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Chris Lattner084a1b52009-11-09 22:57:59 +00001//===- InstructionSimplify.cpp - Fold instruction operands ----------------===//
2//
Chandler Carruth2946cd72019-01-19 08:50:56 +00003// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
Chris Lattner084a1b52009-11-09 22:57:59 +00006//
7//===----------------------------------------------------------------------===//
8//
9// This file implements routines for folding instructions into simpler forms
Duncan Sandsa0219882010-11-23 10:50:08 +000010// that do not require creating new instructions. This does constant folding
11// ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
12// returning a constant ("and i32 %x, 0" -> "0") or an already existing value
Duncan Sandsed6d6c32010-12-20 14:47:04 +000013// ("and i32 %x, %x" -> "%x"). All operands are assumed to have already been
14// simplified: This is usually true and assuming it simplifies the logic (if
15// they have not been simplified then results are correct but maybe suboptimal).
Chris Lattner084a1b52009-11-09 22:57:59 +000016//
17//===----------------------------------------------------------------------===//
18
19#include "llvm/Analysis/InstructionSimplify.h"
Chandler Carruthed0881b2012-12-03 16:50:05 +000020#include "llvm/ADT/SetVector.h"
21#include "llvm/ADT/Statistic.h"
Hal Finkelafcd8db2014-12-01 23:38:06 +000022#include "llvm/Analysis/AliasAnalysis.h"
Daniel Berlin4d0fe642017-04-28 19:55:38 +000023#include "llvm/Analysis/AssumptionCache.h"
Anna Thomas43d7e1c2016-05-03 14:58:21 +000024#include "llvm/Analysis/CaptureTracking.h"
Craig Topper0aa3a192017-08-14 21:39:51 +000025#include "llvm/Analysis/CmpInstAnalysis.h"
Chris Lattner084a1b52009-11-09 22:57:59 +000026#include "llvm/Analysis/ConstantFolding.h"
Daniel Berlin4d0fe642017-04-28 19:55:38 +000027#include "llvm/Analysis/LoopAnalysisManager.h"
Dan Gohmanb3e2d3a2013-02-01 00:11:13 +000028#include "llvm/Analysis/MemoryBuiltins.h"
Chandler Carruth8a8cd2b2014-01-07 11:48:04 +000029#include "llvm/Analysis/ValueTracking.h"
David Majnemer599ca442015-07-13 01:15:53 +000030#include "llvm/Analysis/VectorUtils.h"
Chandler Carruth8cd041e2014-03-04 12:24:34 +000031#include "llvm/IR/ConstantRange.h"
Chandler Carruth9fb823b2013-01-02 11:36:10 +000032#include "llvm/IR/DataLayout.h"
Chandler Carruth5ad5f152014-01-13 09:26:24 +000033#include "llvm/IR/Dominators.h"
Chandler Carruth03eb0de2014-03-04 10:40:04 +000034#include "llvm/IR/GetElementPtrTypeIterator.h"
Chandler Carruth9fb823b2013-01-02 11:36:10 +000035#include "llvm/IR/GlobalAlias.h"
Chandler Carruthdac20a82019-02-11 07:54:10 +000036#include "llvm/IR/InstrTypes.h"
37#include "llvm/IR/Instructions.h"
Chandler Carruth9fb823b2013-01-02 11:36:10 +000038#include "llvm/IR/Operator.h"
Chandler Carruth820a9082014-03-04 11:08:18 +000039#include "llvm/IR/PatternMatch.h"
Chandler Carruth4220e9c2014-03-04 11:17:44 +000040#include "llvm/IR/ValueHandle.h"
Craig Topperb45eabc2017-04-26 16:39:58 +000041#include "llvm/Support/KnownBits.h"
Hal Finkelafcd8db2014-12-01 23:38:06 +000042#include <algorithm>
Chris Lattner084a1b52009-11-09 22:57:59 +000043using namespace llvm;
Chris Lattnera71e9d62009-11-10 00:55:12 +000044using namespace llvm::PatternMatch;
Chris Lattner084a1b52009-11-09 22:57:59 +000045
Chandler Carruthf1221bd2014-04-22 02:48:03 +000046#define DEBUG_TYPE "instsimplify"
47
Chris Lattner9e4aa022011-02-09 17:15:04 +000048enum { RecursionLimit = 3 };
Duncan Sandsf3b1bf12010-11-10 18:23:01 +000049
Duncan Sands3547d2e2010-12-22 09:40:51 +000050STATISTIC(NumExpand, "Number of expansions");
Duncan Sands3547d2e2010-12-22 09:40:51 +000051STATISTIC(NumReassoc, "Number of reassociations");
52
Daniel Berlin5e3fcb12017-04-26 04:09:56 +000053static Value *SimplifyAndInst(Value *, Value *, const SimplifyQuery &, unsigned);
Cameron McInallyc3167692019-05-06 16:05:10 +000054static Value *simplifyUnOp(unsigned, Value *, const SimplifyQuery &, unsigned);
55static Value *simplifyFPUnOp(unsigned, Value *, const FastMathFlags &,
56 const SimplifyQuery &, unsigned);
Daniel Berlin5e3fcb12017-04-26 04:09:56 +000057static Value *SimplifyBinOp(unsigned, Value *, Value *, const SimplifyQuery &,
Chad Rosierc24b86f2011-12-01 03:08:23 +000058 unsigned);
Jay Foad565c5432019-07-24 12:50:10 +000059static Value *SimplifyBinOp(unsigned, Value *, Value *, const FastMathFlags &,
60 const SimplifyQuery &, unsigned);
Daniel Berlin5e3fcb12017-04-26 04:09:56 +000061static Value *SimplifyCmpInst(unsigned, Value *, Value *, const SimplifyQuery &,
Chad Rosierc24b86f2011-12-01 03:08:23 +000062 unsigned);
Sanjay Patel9d5b5e32016-12-03 18:03:53 +000063static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +000064 const SimplifyQuery &Q, unsigned MaxRecurse);
65static Value *SimplifyOrInst(Value *, Value *, const SimplifyQuery &, unsigned);
66static Value *SimplifyXorInst(Value *, Value *, const SimplifyQuery &, unsigned);
David Majnemer6774d612016-07-26 17:58:05 +000067static Value *SimplifyCastInst(unsigned, Value *, Type *,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +000068 const SimplifyQuery &, unsigned);
George Burgess IV8e807bf2018-04-24 00:25:01 +000069static Value *SimplifyGEPInst(Type *, ArrayRef<Value *>, const SimplifyQuery &,
70 unsigned);
Duncan Sands5ffc2982010-11-16 12:16:38 +000071
David Bolvanskyf9476082018-07-28 06:55:51 +000072static Value *foldSelectWithBinaryOp(Value *Cond, Value *TrueVal,
73 Value *FalseVal) {
74 BinaryOperator::BinaryOps BinOpCode;
75 if (auto *BO = dyn_cast<BinaryOperator>(Cond))
76 BinOpCode = BO->getOpcode();
77 else
78 return nullptr;
79
David Bolvansky16d8a692018-07-31 14:17:15 +000080 CmpInst::Predicate ExpectedPred, Pred1, Pred2;
David Bolvanskyf9476082018-07-28 06:55:51 +000081 if (BinOpCode == BinaryOperator::Or) {
82 ExpectedPred = ICmpInst::ICMP_NE;
83 } else if (BinOpCode == BinaryOperator::And) {
84 ExpectedPred = ICmpInst::ICMP_EQ;
85 } else
86 return nullptr;
87
David Bolvansky16d8a692018-07-31 14:17:15 +000088 // %A = icmp eq %TV, %FV
89 // %B = icmp eq %X, %Y (and one of these is a select operand)
90 // %C = and %A, %B
91 // %D = select %C, %TV, %FV
92 // -->
93 // %FV
94
95 // %A = icmp ne %TV, %FV
96 // %B = icmp ne %X, %Y (and one of these is a select operand)
97 // %C = or %A, %B
98 // %D = select %C, %TV, %FV
99 // -->
100 // %TV
101 Value *X, *Y;
102 if (!match(Cond, m_c_BinOp(m_c_ICmp(Pred1, m_Specific(TrueVal),
103 m_Specific(FalseVal)),
104 m_ICmp(Pred2, m_Value(X), m_Value(Y)))) ||
David Bolvanskyf9476082018-07-28 06:55:51 +0000105 Pred1 != Pred2 || Pred1 != ExpectedPred)
106 return nullptr;
107
David Bolvansky16d8a692018-07-31 14:17:15 +0000108 if (X == TrueVal || X == FalseVal || Y == TrueVal || Y == FalseVal)
109 return BinOpCode == BinaryOperator::Or ? TrueVal : FalseVal;
110
111 return nullptr;
David Bolvanskyf9476082018-07-28 06:55:51 +0000112}
113
Sanjay Patel35ed2412017-04-16 17:43:11 +0000114/// For a boolean type or a vector of boolean type, return false or a vector
115/// with every element false.
Duncan Sandsc1c92712011-07-26 15:03:53 +0000116static Constant *getFalse(Type *Ty) {
Sanjay Patel35ed2412017-04-16 17:43:11 +0000117 return ConstantInt::getFalse(Ty);
Duncan Sandsc1c92712011-07-26 15:03:53 +0000118}
119
Sanjay Patel35ed2412017-04-16 17:43:11 +0000120/// For a boolean type or a vector of boolean type, return true or a vector
121/// with every element true.
Duncan Sandsc1c92712011-07-26 15:03:53 +0000122static Constant *getTrue(Type *Ty) {
Sanjay Patel35ed2412017-04-16 17:43:11 +0000123 return ConstantInt::getTrue(Ty);
Duncan Sandsc1c92712011-07-26 15:03:53 +0000124}
125
Duncan Sands3d5692a2011-10-30 19:56:36 +0000126/// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
127static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
128 Value *RHS) {
129 CmpInst *Cmp = dyn_cast<CmpInst>(V);
130 if (!Cmp)
131 return false;
132 CmpInst::Predicate CPred = Cmp->getPredicate();
133 Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
134 if (CPred == Pred && CLHS == LHS && CRHS == RHS)
135 return true;
136 return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
137 CRHS == LHS;
138}
139
Sanjay Patel472cc782016-01-11 22:14:42 +0000140/// Does the given value dominate the specified phi node?
Sanjay Patel5da361a2018-04-10 18:38:19 +0000141static bool valueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
Duncan Sands5ffc2982010-11-16 12:16:38 +0000142 Instruction *I = dyn_cast<Instruction>(V);
143 if (!I)
144 // Arguments and constants dominate all instructions.
145 return true;
146
Chandler Carruth3ffccb32012-03-21 10:58:47 +0000147 // If we are processing instructions (and/or basic blocks) that have not been
148 // fully added to a function, the parent nodes may still be null. Simply
149 // return the conservative answer in these cases.
Sanjay Patel5da361a2018-04-10 18:38:19 +0000150 if (!I->getParent() || !P->getParent() || !I->getFunction())
Chandler Carruth3ffccb32012-03-21 10:58:47 +0000151 return false;
152
Duncan Sands5ffc2982010-11-16 12:16:38 +0000153 // If we have a DominatorTree then do a precise test.
Daniel Berlin71ff6632017-05-31 01:47:24 +0000154 if (DT)
Eli Friedmanc8cbd062012-03-13 01:06:07 +0000155 return DT->dominates(I, P);
Duncan Sands5ffc2982010-11-16 12:16:38 +0000156
David Majnemer8a1c45d2015-12-12 05:38:55 +0000157 // Otherwise, if the instruction is in the entry block and is not an invoke,
158 // then it obviously dominates all phi nodes.
Sanjay Patel5da361a2018-04-10 18:38:19 +0000159 if (I->getParent() == &I->getFunction()->getEntryBlock() &&
David Majnemer8a1c45d2015-12-12 05:38:55 +0000160 !isa<InvokeInst>(I))
Duncan Sands5ffc2982010-11-16 12:16:38 +0000161 return true;
162
163 return false;
164}
Duncan Sandsf3b1bf12010-11-10 18:23:01 +0000165
Sanjay Patel472cc782016-01-11 22:14:42 +0000166/// Simplify "A op (B op' C)" by distributing op over op', turning it into
167/// "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000168/// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
169/// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
170/// Returns the simplified value, or null if no simplification was performed.
Craig Topper60dd9cd2017-04-07 05:57:51 +0000171static Value *ExpandBinOp(Instruction::BinaryOps Opcode, Value *LHS, Value *RHS,
Craig Topper9c913bf2017-05-19 16:56:53 +0000172 Instruction::BinaryOps OpcodeToExpand,
173 const SimplifyQuery &Q, unsigned MaxRecurse) {
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000174 // Recursion is always used, so bail out at once if we already hit the limit.
175 if (!MaxRecurse--)
Craig Topper9f008862014-04-15 04:59:12 +0000176 return nullptr;
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000177
178 // Check whether the expression has the form "(A op' B) op C".
179 if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
180 if (Op0->getOpcode() == OpcodeToExpand) {
181 // It does! Try turning it into "(A op C) op' (B op C)".
182 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
183 // Do "A op C" and "B op C" both simplify?
Duncan Sandsb8cee002012-03-13 11:42:19 +0000184 if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
185 if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000186 // They do! Return "L op' R" if it simplifies or is already available.
187 // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
Duncan Sands772749a2011-01-01 20:08:02 +0000188 if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
189 && L == B && R == A)) {
Duncan Sands3547d2e2010-12-22 09:40:51 +0000190 ++NumExpand;
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000191 return LHS;
Duncan Sands3547d2e2010-12-22 09:40:51 +0000192 }
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000193 // Otherwise return "L op' R" if it simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000194 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
Duncan Sands3547d2e2010-12-22 09:40:51 +0000195 ++NumExpand;
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000196 return V;
Duncan Sands3547d2e2010-12-22 09:40:51 +0000197 }
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000198 }
199 }
200
201 // Check whether the expression has the form "A op (B op' C)".
202 if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
203 if (Op1->getOpcode() == OpcodeToExpand) {
204 // It does! Try turning it into "(A op B) op' (A op C)".
205 Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
206 // Do "A op B" and "A op C" both simplify?
Duncan Sandsb8cee002012-03-13 11:42:19 +0000207 if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
208 if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000209 // They do! Return "L op' R" if it simplifies or is already available.
210 // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
Duncan Sands772749a2011-01-01 20:08:02 +0000211 if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
212 && L == C && R == B)) {
Duncan Sands3547d2e2010-12-22 09:40:51 +0000213 ++NumExpand;
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000214 return RHS;
Duncan Sands3547d2e2010-12-22 09:40:51 +0000215 }
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000216 // Otherwise return "L op' R" if it simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000217 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
Duncan Sands3547d2e2010-12-22 09:40:51 +0000218 ++NumExpand;
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000219 return V;
Duncan Sands3547d2e2010-12-22 09:40:51 +0000220 }
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000221 }
222 }
223
Craig Topper9f008862014-04-15 04:59:12 +0000224 return nullptr;
Duncan Sandsee3ec6e2010-12-21 13:32:22 +0000225}
226
Sanjay Patel472cc782016-01-11 22:14:42 +0000227/// Generic simplifications for associative binary operations.
228/// Returns the simpler value, or null if none was found.
Craig Topper60dd9cd2017-04-07 05:57:51 +0000229static Value *SimplifyAssociativeBinOp(Instruction::BinaryOps Opcode,
Craig Topper9c913bf2017-05-19 16:56:53 +0000230 Value *LHS, Value *RHS,
231 const SimplifyQuery &Q,
Craig Topper60dd9cd2017-04-07 05:57:51 +0000232 unsigned MaxRecurse) {
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000233 assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
234
235 // Recursion is always used, so bail out at once if we already hit the limit.
236 if (!MaxRecurse--)
Craig Topper9f008862014-04-15 04:59:12 +0000237 return nullptr;
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000238
239 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
240 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
241
242 // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
243 if (Op0 && Op0->getOpcode() == Opcode) {
244 Value *A = Op0->getOperand(0);
245 Value *B = Op0->getOperand(1);
246 Value *C = RHS;
247
248 // Does "B op C" simplify?
Duncan Sandsb8cee002012-03-13 11:42:19 +0000249 if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000250 // It does! Return "A op V" if it simplifies or is already available.
251 // If V equals B then "A op V" is just the LHS.
Duncan Sands772749a2011-01-01 20:08:02 +0000252 if (V == B) return LHS;
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000253 // Otherwise return "A op V" if it simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000254 if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
Duncan Sands3547d2e2010-12-22 09:40:51 +0000255 ++NumReassoc;
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000256 return W;
Duncan Sands3547d2e2010-12-22 09:40:51 +0000257 }
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000258 }
259 }
260
261 // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
262 if (Op1 && Op1->getOpcode() == Opcode) {
263 Value *A = LHS;
264 Value *B = Op1->getOperand(0);
265 Value *C = Op1->getOperand(1);
266
267 // Does "A op B" simplify?
Duncan Sandsb8cee002012-03-13 11:42:19 +0000268 if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000269 // It does! Return "V op C" if it simplifies or is already available.
270 // If V equals B then "V op C" is just the RHS.
Duncan Sands772749a2011-01-01 20:08:02 +0000271 if (V == B) return RHS;
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000272 // Otherwise return "V op C" if it simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000273 if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
Duncan Sands3547d2e2010-12-22 09:40:51 +0000274 ++NumReassoc;
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000275 return W;
Duncan Sands3547d2e2010-12-22 09:40:51 +0000276 }
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000277 }
278 }
279
280 // The remaining transforms require commutativity as well as associativity.
281 if (!Instruction::isCommutative(Opcode))
Craig Topper9f008862014-04-15 04:59:12 +0000282 return nullptr;
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000283
284 // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
285 if (Op0 && Op0->getOpcode() == Opcode) {
286 Value *A = Op0->getOperand(0);
287 Value *B = Op0->getOperand(1);
288 Value *C = RHS;
289
290 // Does "C op A" simplify?
Duncan Sandsb8cee002012-03-13 11:42:19 +0000291 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000292 // It does! Return "V op B" if it simplifies or is already available.
293 // If V equals A then "V op B" is just the LHS.
Duncan Sands772749a2011-01-01 20:08:02 +0000294 if (V == A) return LHS;
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000295 // Otherwise return "V op B" if it simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000296 if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
Duncan Sands3547d2e2010-12-22 09:40:51 +0000297 ++NumReassoc;
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000298 return W;
Duncan Sands3547d2e2010-12-22 09:40:51 +0000299 }
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000300 }
301 }
302
303 // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
304 if (Op1 && Op1->getOpcode() == Opcode) {
305 Value *A = LHS;
306 Value *B = Op1->getOperand(0);
307 Value *C = Op1->getOperand(1);
308
309 // Does "C op A" simplify?
Duncan Sandsb8cee002012-03-13 11:42:19 +0000310 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000311 // It does! Return "B op V" if it simplifies or is already available.
312 // If V equals C then "B op V" is just the RHS.
Duncan Sands772749a2011-01-01 20:08:02 +0000313 if (V == C) return RHS;
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000314 // Otherwise return "B op V" if it simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000315 if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
Duncan Sands3547d2e2010-12-22 09:40:51 +0000316 ++NumReassoc;
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000317 return W;
Duncan Sands3547d2e2010-12-22 09:40:51 +0000318 }
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000319 }
320 }
321
Craig Topper9f008862014-04-15 04:59:12 +0000322 return nullptr;
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000323}
324
Sanjay Patel472cc782016-01-11 22:14:42 +0000325/// In the case of a binary operation with a select instruction as an operand,
326/// try to simplify the binop by seeing whether evaluating it on both branches
327/// of the select results in the same value. Returns the common value if so,
328/// otherwise returns null.
Craig Topper60dd9cd2017-04-07 05:57:51 +0000329static Value *ThreadBinOpOverSelect(Instruction::BinaryOps Opcode, Value *LHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +0000330 Value *RHS, const SimplifyQuery &Q,
Craig Topper60dd9cd2017-04-07 05:57:51 +0000331 unsigned MaxRecurse) {
Duncan Sandsf64e6902010-12-21 09:09:15 +0000332 // Recursion is always used, so bail out at once if we already hit the limit.
333 if (!MaxRecurse--)
Craig Topper9f008862014-04-15 04:59:12 +0000334 return nullptr;
Duncan Sandsf64e6902010-12-21 09:09:15 +0000335
Duncan Sandsb0579e92010-11-10 13:00:08 +0000336 SelectInst *SI;
337 if (isa<SelectInst>(LHS)) {
338 SI = cast<SelectInst>(LHS);
339 } else {
340 assert(isa<SelectInst>(RHS) && "No select instruction operand!");
341 SI = cast<SelectInst>(RHS);
342 }
343
344 // Evaluate the BinOp on the true and false branches of the select.
345 Value *TV;
346 Value *FV;
347 if (SI == LHS) {
Duncan Sandsb8cee002012-03-13 11:42:19 +0000348 TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
349 FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
Duncan Sandsb0579e92010-11-10 13:00:08 +0000350 } else {
Duncan Sandsb8cee002012-03-13 11:42:19 +0000351 TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
352 FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
Duncan Sandsb0579e92010-11-10 13:00:08 +0000353 }
354
Duncan Sandse3c53952011-01-01 16:12:09 +0000355 // If they simplified to the same value, then return the common value.
Duncan Sands772749a2011-01-01 20:08:02 +0000356 // If they both failed to simplify then return null.
357 if (TV == FV)
Duncan Sandsb0579e92010-11-10 13:00:08 +0000358 return TV;
359
360 // If one branch simplified to undef, return the other one.
361 if (TV && isa<UndefValue>(TV))
362 return FV;
363 if (FV && isa<UndefValue>(FV))
364 return TV;
365
366 // If applying the operation did not change the true and false select values,
367 // then the result of the binop is the select itself.
Duncan Sands772749a2011-01-01 20:08:02 +0000368 if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
Duncan Sandsb0579e92010-11-10 13:00:08 +0000369 return SI;
370
371 // If one branch simplified and the other did not, and the simplified
372 // value is equal to the unsimplified one, return the simplified value.
373 // For example, select (cond, X, X & Z) & Z -> X & Z.
374 if ((FV && !TV) || (TV && !FV)) {
375 // Check that the simplified value has the form "X op Y" where "op" is the
376 // same as the original operation.
377 Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
Zachary Turner260fe3e2017-12-14 22:07:03 +0000378 if (Simplified && Simplified->getOpcode() == unsigned(Opcode)) {
Duncan Sandsb0579e92010-11-10 13:00:08 +0000379 // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
380 // We already know that "op" is the same as for the simplified value. See
381 // if the operands match too. If so, return the simplified value.
382 Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
383 Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
384 Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
Duncan Sands772749a2011-01-01 20:08:02 +0000385 if (Simplified->getOperand(0) == UnsimplifiedLHS &&
386 Simplified->getOperand(1) == UnsimplifiedRHS)
Duncan Sandsb0579e92010-11-10 13:00:08 +0000387 return Simplified;
388 if (Simplified->isCommutative() &&
Duncan Sands772749a2011-01-01 20:08:02 +0000389 Simplified->getOperand(1) == UnsimplifiedLHS &&
390 Simplified->getOperand(0) == UnsimplifiedRHS)
Duncan Sandsb0579e92010-11-10 13:00:08 +0000391 return Simplified;
392 }
393 }
394
Craig Topper9f008862014-04-15 04:59:12 +0000395 return nullptr;
Duncan Sandsb0579e92010-11-10 13:00:08 +0000396}
397
Sanjay Patel472cc782016-01-11 22:14:42 +0000398/// In the case of a comparison with a select instruction, try to simplify the
399/// comparison by seeing whether both branches of the select result in the same
400/// value. Returns the common value if so, otherwise returns null.
Duncan Sandsb0579e92010-11-10 13:00:08 +0000401static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +0000402 Value *RHS, const SimplifyQuery &Q,
Duncan Sandsf3b1bf12010-11-10 18:23:01 +0000403 unsigned MaxRecurse) {
Duncan Sandsf64e6902010-12-21 09:09:15 +0000404 // Recursion is always used, so bail out at once if we already hit the limit.
405 if (!MaxRecurse--)
Craig Topper9f008862014-04-15 04:59:12 +0000406 return nullptr;
Duncan Sandsf64e6902010-12-21 09:09:15 +0000407
Duncan Sandsb0579e92010-11-10 13:00:08 +0000408 // Make sure the select is on the LHS.
409 if (!isa<SelectInst>(LHS)) {
410 std::swap(LHS, RHS);
411 Pred = CmpInst::getSwappedPredicate(Pred);
412 }
413 assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
414 SelectInst *SI = cast<SelectInst>(LHS);
Duncan Sands3d5692a2011-10-30 19:56:36 +0000415 Value *Cond = SI->getCondition();
416 Value *TV = SI->getTrueValue();
417 Value *FV = SI->getFalseValue();
Duncan Sandsb0579e92010-11-10 13:00:08 +0000418
Duncan Sands06504022011-02-03 09:37:39 +0000419 // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
Duncan Sandsb0579e92010-11-10 13:00:08 +0000420 // Does "cmp TV, RHS" simplify?
Duncan Sandsb8cee002012-03-13 11:42:19 +0000421 Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
Duncan Sands3d5692a2011-10-30 19:56:36 +0000422 if (TCmp == Cond) {
423 // It not only simplified, it simplified to the select condition. Replace
424 // it with 'true'.
425 TCmp = getTrue(Cond->getType());
426 } else if (!TCmp) {
427 // It didn't simplify. However if "cmp TV, RHS" is equal to the select
428 // condition then we can replace it with 'true'. Otherwise give up.
429 if (!isSameCompare(Cond, Pred, TV, RHS))
Craig Topper9f008862014-04-15 04:59:12 +0000430 return nullptr;
Duncan Sands3d5692a2011-10-30 19:56:36 +0000431 TCmp = getTrue(Cond->getType());
Duncan Sands06504022011-02-03 09:37:39 +0000432 }
433
Duncan Sands3d5692a2011-10-30 19:56:36 +0000434 // Does "cmp FV, RHS" simplify?
Duncan Sandsb8cee002012-03-13 11:42:19 +0000435 Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
Duncan Sands3d5692a2011-10-30 19:56:36 +0000436 if (FCmp == Cond) {
437 // It not only simplified, it simplified to the select condition. Replace
438 // it with 'false'.
439 FCmp = getFalse(Cond->getType());
440 } else if (!FCmp) {
441 // It didn't simplify. However if "cmp FV, RHS" is equal to the select
442 // condition then we can replace it with 'false'. Otherwise give up.
443 if (!isSameCompare(Cond, Pred, FV, RHS))
Craig Topper9f008862014-04-15 04:59:12 +0000444 return nullptr;
Duncan Sands3d5692a2011-10-30 19:56:36 +0000445 FCmp = getFalse(Cond->getType());
446 }
447
448 // If both sides simplified to the same value, then use it as the result of
449 // the original comparison.
450 if (TCmp == FCmp)
451 return TCmp;
Duncan Sands26641d72012-02-10 14:31:24 +0000452
453 // The remaining cases only make sense if the select condition has the same
454 // type as the result of the comparison, so bail out if this is not so.
455 if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
Craig Topper9f008862014-04-15 04:59:12 +0000456 return nullptr;
Duncan Sands3d5692a2011-10-30 19:56:36 +0000457 // If the false value simplified to false, then the result of the compare
458 // is equal to "Cond && TCmp". This also catches the case when the false
459 // value simplified to false and the true value to true, returning "Cond".
460 if (match(FCmp, m_Zero()))
Duncan Sandsb8cee002012-03-13 11:42:19 +0000461 if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
Duncan Sands3d5692a2011-10-30 19:56:36 +0000462 return V;
463 // If the true value simplified to true, then the result of the compare
464 // is equal to "Cond || FCmp".
465 if (match(TCmp, m_One()))
Duncan Sandsb8cee002012-03-13 11:42:19 +0000466 if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
Duncan Sands3d5692a2011-10-30 19:56:36 +0000467 return V;
468 // Finally, if the false value simplified to true and the true value to
469 // false, then the result of the compare is equal to "!Cond".
470 if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
471 if (Value *V =
472 SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
Duncan Sandsb8cee002012-03-13 11:42:19 +0000473 Q, MaxRecurse))
Duncan Sands3d5692a2011-10-30 19:56:36 +0000474 return V;
475
Craig Topper9f008862014-04-15 04:59:12 +0000476 return nullptr;
Duncan Sandsb0579e92010-11-10 13:00:08 +0000477}
478
Sanjay Patel472cc782016-01-11 22:14:42 +0000479/// In the case of a binary operation with an operand that is a PHI instruction,
480/// try to simplify the binop by seeing whether evaluating it on the incoming
481/// phi values yields the same result for every value. If so returns the common
482/// value, otherwise returns null.
Craig Topper60dd9cd2017-04-07 05:57:51 +0000483static Value *ThreadBinOpOverPHI(Instruction::BinaryOps Opcode, Value *LHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +0000484 Value *RHS, const SimplifyQuery &Q,
Craig Topper60dd9cd2017-04-07 05:57:51 +0000485 unsigned MaxRecurse) {
Duncan Sandsf64e6902010-12-21 09:09:15 +0000486 // Recursion is always used, so bail out at once if we already hit the limit.
487 if (!MaxRecurse--)
Craig Topper9f008862014-04-15 04:59:12 +0000488 return nullptr;
Duncan Sandsf64e6902010-12-21 09:09:15 +0000489
Duncan Sandsf3b1bf12010-11-10 18:23:01 +0000490 PHINode *PI;
491 if (isa<PHINode>(LHS)) {
492 PI = cast<PHINode>(LHS);
Duncan Sands5ffc2982010-11-16 12:16:38 +0000493 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
Sanjay Patel5da361a2018-04-10 18:38:19 +0000494 if (!valueDominatesPHI(RHS, PI, Q.DT))
Craig Topper9f008862014-04-15 04:59:12 +0000495 return nullptr;
Duncan Sandsf3b1bf12010-11-10 18:23:01 +0000496 } else {
497 assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
498 PI = cast<PHINode>(RHS);
Duncan Sands5ffc2982010-11-16 12:16:38 +0000499 // Bail out if LHS and the phi may be mutually interdependent due to a loop.
Sanjay Patel5da361a2018-04-10 18:38:19 +0000500 if (!valueDominatesPHI(LHS, PI, Q.DT))
Craig Topper9f008862014-04-15 04:59:12 +0000501 return nullptr;
Duncan Sandsf3b1bf12010-11-10 18:23:01 +0000502 }
503
504 // Evaluate the BinOp on the incoming phi values.
Craig Topper9f008862014-04-15 04:59:12 +0000505 Value *CommonValue = nullptr;
Pete Cooper833f34d2015-05-12 20:05:31 +0000506 for (Value *Incoming : PI->incoming_values()) {
Duncan Sands7412f6e2010-11-17 04:30:22 +0000507 // If the incoming value is the phi node itself, it can safely be skipped.
Duncan Sandsf12ba1d2010-11-15 17:52:45 +0000508 if (Incoming == PI) continue;
Duncan Sandsf3b1bf12010-11-10 18:23:01 +0000509 Value *V = PI == LHS ?
Duncan Sandsb8cee002012-03-13 11:42:19 +0000510 SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
511 SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
Duncan Sandsf3b1bf12010-11-10 18:23:01 +0000512 // If the operation failed to simplify, or simplified to a different value
513 // to previously, then give up.
514 if (!V || (CommonValue && V != CommonValue))
Craig Topper9f008862014-04-15 04:59:12 +0000515 return nullptr;
Duncan Sandsf3b1bf12010-11-10 18:23:01 +0000516 CommonValue = V;
517 }
518
519 return CommonValue;
520}
521
Sanjay Patel472cc782016-01-11 22:14:42 +0000522/// In the case of a comparison with a PHI instruction, try to simplify the
523/// comparison by seeing whether comparing with all of the incoming phi values
524/// yields the same result every time. If so returns the common result,
525/// otherwise returns null.
Duncan Sandsf3b1bf12010-11-10 18:23:01 +0000526static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +0000527 const SimplifyQuery &Q, unsigned MaxRecurse) {
Duncan Sandsf64e6902010-12-21 09:09:15 +0000528 // Recursion is always used, so bail out at once if we already hit the limit.
529 if (!MaxRecurse--)
Craig Topper9f008862014-04-15 04:59:12 +0000530 return nullptr;
Duncan Sandsf64e6902010-12-21 09:09:15 +0000531
Duncan Sandsf3b1bf12010-11-10 18:23:01 +0000532 // Make sure the phi is on the LHS.
533 if (!isa<PHINode>(LHS)) {
534 std::swap(LHS, RHS);
535 Pred = CmpInst::getSwappedPredicate(Pred);
536 }
537 assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
538 PHINode *PI = cast<PHINode>(LHS);
539
Duncan Sands5ffc2982010-11-16 12:16:38 +0000540 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
Sanjay Patel5da361a2018-04-10 18:38:19 +0000541 if (!valueDominatesPHI(RHS, PI, Q.DT))
Craig Topper9f008862014-04-15 04:59:12 +0000542 return nullptr;
Duncan Sands5ffc2982010-11-16 12:16:38 +0000543
Duncan Sandsf3b1bf12010-11-10 18:23:01 +0000544 // Evaluate the BinOp on the incoming phi values.
Craig Topper9f008862014-04-15 04:59:12 +0000545 Value *CommonValue = nullptr;
Pete Cooper833f34d2015-05-12 20:05:31 +0000546 for (Value *Incoming : PI->incoming_values()) {
Duncan Sands7412f6e2010-11-17 04:30:22 +0000547 // If the incoming value is the phi node itself, it can safely be skipped.
Duncan Sandsf12ba1d2010-11-15 17:52:45 +0000548 if (Incoming == PI) continue;
Duncan Sandsb8cee002012-03-13 11:42:19 +0000549 Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
Duncan Sandsf3b1bf12010-11-10 18:23:01 +0000550 // If the operation failed to simplify, or simplified to a different value
551 // to previously, then give up.
552 if (!V || (CommonValue && V != CommonValue))
Craig Topper9f008862014-04-15 04:59:12 +0000553 return nullptr;
Duncan Sandsf3b1bf12010-11-10 18:23:01 +0000554 CommonValue = V;
555 }
556
557 return CommonValue;
558}
559
Sanjay Patel8b5ad3f2017-04-01 19:05:11 +0000560static Constant *foldOrCommuteConstant(Instruction::BinaryOps Opcode,
561 Value *&Op0, Value *&Op1,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +0000562 const SimplifyQuery &Q) {
Sanjay Patel8b5ad3f2017-04-01 19:05:11 +0000563 if (auto *CLHS = dyn_cast<Constant>(Op0)) {
564 if (auto *CRHS = dyn_cast<Constant>(Op1))
565 return ConstantFoldBinaryOpOperands(Opcode, CLHS, CRHS, Q.DL);
566
567 // Canonicalize the constant to the RHS if this is a commutative operation.
568 if (Instruction::isCommutative(Opcode))
569 std::swap(Op0, Op1);
570 }
571 return nullptr;
572}
573
Sanjay Patel472cc782016-01-11 22:14:42 +0000574/// Given operands for an Add, see if we can fold the result.
575/// If not, this returns null.
Roman Lebedevf87321a2018-06-08 15:44:53 +0000576static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool IsNSW, bool IsNUW,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +0000577 const SimplifyQuery &Q, unsigned MaxRecurse) {
Sanjay Patel8b5ad3f2017-04-01 19:05:11 +0000578 if (Constant *C = foldOrCommuteConstant(Instruction::Add, Op0, Op1, Q))
579 return C;
Duncan Sands7e800d62010-11-14 11:23:23 +0000580
Duncan Sands0a2c41682010-12-15 14:07:39 +0000581 // X + undef -> undef
Duncan Sandsa29ea9a2011-02-01 09:06:20 +0000582 if (match(Op1, m_Undef()))
Duncan Sands0a2c41682010-12-15 14:07:39 +0000583 return Op1;
Duncan Sands7e800d62010-11-14 11:23:23 +0000584
Duncan Sands0a2c41682010-12-15 14:07:39 +0000585 // X + 0 -> X
586 if (match(Op1, m_Zero()))
587 return Op0;
Duncan Sands7e800d62010-11-14 11:23:23 +0000588
Chen Zhengfdf13ef2018-07-12 03:06:04 +0000589 // If two operands are negative, return 0.
590 if (isKnownNegation(Op0, Op1))
591 return Constant::getNullValue(Op0->getType());
592
Duncan Sands0a2c41682010-12-15 14:07:39 +0000593 // X + (Y - X) -> Y
594 // (Y - X) + X -> Y
Duncan Sandsed6d6c32010-12-20 14:47:04 +0000595 // Eg: X + -X -> 0
Craig Topper9f008862014-04-15 04:59:12 +0000596 Value *Y = nullptr;
Duncan Sands772749a2011-01-01 20:08:02 +0000597 if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
598 match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
Duncan Sands0a2c41682010-12-15 14:07:39 +0000599 return Y;
600
601 // X + ~X -> -1 since ~X = -X-1
Sanjay Patelfe672552017-02-18 21:59:09 +0000602 Type *Ty = Op0->getType();
Duncan Sands772749a2011-01-01 20:08:02 +0000603 if (match(Op0, m_Not(m_Specific(Op1))) ||
604 match(Op1, m_Not(m_Specific(Op0))))
Sanjay Patelfe672552017-02-18 21:59:09 +0000605 return Constant::getAllOnesValue(Ty);
606
Craig Topperbcfd2d12017-04-20 16:56:25 +0000607 // add nsw/nuw (xor Y, signmask), signmask --> Y
Sanjay Patelfe672552017-02-18 21:59:09 +0000608 // The no-wrapping add guarantees that the top bit will be set by the add.
609 // Therefore, the xor must be clearing the already set sign bit of Y.
Roman Lebedevf87321a2018-06-08 15:44:53 +0000610 if ((IsNSW || IsNUW) && match(Op1, m_SignMask()) &&
Craig Topperbcfd2d12017-04-20 16:56:25 +0000611 match(Op0, m_Xor(m_Value(Y), m_SignMask())))
Sanjay Patelfe672552017-02-18 21:59:09 +0000612 return Y;
Duncan Sandsb238de02010-11-19 09:20:39 +0000613
Roman Lebedevb060ce42018-06-08 15:44:47 +0000614 // add nuw %x, -1 -> -1, because %x can only be 0.
Roman Lebedevf87321a2018-06-08 15:44:53 +0000615 if (IsNUW && match(Op1, m_AllOnes()))
Roman Lebedevb060ce42018-06-08 15:44:47 +0000616 return Op1; // Which is -1.
617
Duncan Sandsd0eb6d32010-12-21 14:00:22 +0000618 /// i1 add -> xor.
Craig Topperfde47232017-07-09 07:04:03 +0000619 if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
Duncan Sandsb8cee002012-03-13 11:42:19 +0000620 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
Duncan Sandsfecc6422010-12-21 15:03:43 +0000621 return V;
Duncan Sandsd0eb6d32010-12-21 14:00:22 +0000622
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000623 // Try some generic simplifications for associative operations.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000624 if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
Duncan Sands6c7a52c2010-12-21 08:49:00 +0000625 MaxRecurse))
626 return V;
627
Duncan Sandsb238de02010-11-19 09:20:39 +0000628 // Threading Add over selects and phi nodes is pointless, so don't bother.
629 // Threading over the select in "A + select(cond, B, C)" means evaluating
630 // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
631 // only if B and C are equal. If B and C are equal then (since we assume
632 // that operands have already been simplified) "select(cond, B, C)" should
633 // have been simplified to the common value of B and C already. Analysing
634 // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
635 // for threading over phi nodes.
636
Craig Topper9f008862014-04-15 04:59:12 +0000637 return nullptr;
Chris Lattner3d9823b2009-11-27 17:42:22 +0000638}
639
Roman Lebedevf87321a2018-06-08 15:44:53 +0000640Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool IsNSW, bool IsNUW,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +0000641 const SimplifyQuery &Query) {
Roman Lebedevf87321a2018-06-08 15:44:53 +0000642 return ::SimplifyAddInst(Op0, Op1, IsNSW, IsNUW, Query, RecursionLimit);
Daniel Berlin5e3fcb12017-04-26 04:09:56 +0000643}
644
Adrian Prantl5f8f34e42018-05-01 15:54:18 +0000645/// Compute the base pointer and cumulative constant offsets for V.
Chandler Carrutha0796552012-03-12 11:19:31 +0000646///
647/// This strips all constant offsets off of V, leaving it the base pointer, and
648/// accumulates the total constant offset applied in the returned constant. It
649/// returns 0 if V is not a pointer, and returns the constant '0' if there are
650/// no constant offsets applied.
Dan Gohman36fa8392013-01-31 02:45:26 +0000651///
652/// This is very similar to GetPointerBaseWithConstantOffset except it doesn't
653/// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc.
654/// folding.
Mehdi Aminia28d91d2015-03-10 02:37:25 +0000655static Constant *stripAndComputeConstantOffsets(const DataLayout &DL, Value *&V,
Benjamin Kramer942dfe62013-09-23 14:16:38 +0000656 bool AllowNonInbounds = false) {
Craig Topper95d23472017-07-09 07:04:00 +0000657 assert(V->getType()->isPtrOrPtrVectorTy());
Chandler Carrutha0796552012-03-12 11:19:31 +0000658
Mehdi Aminia28d91d2015-03-10 02:37:25 +0000659 Type *IntPtrTy = DL.getIntPtrType(V->getType())->getScalarType();
Matt Arsenault2f9cce22013-08-03 01:03:12 +0000660 APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());
Chandler Carrutha0796552012-03-12 11:19:31 +0000661
Johannes Doerfert3ed286a2019-07-11 01:14:48 +0000662 V = V->stripAndAccumulateConstantOffsets(DL, Offset, AllowNonInbounds);
Michael Liao543ba4e2019-07-16 01:03:06 +0000663 // As that strip may trace through `addrspacecast`, need to sext or trunc
664 // the offset calculated.
665 IntPtrTy = DL.getIntPtrType(V->getType())->getScalarType();
666 Offset = Offset.sextOrTrunc(IntPtrTy->getIntegerBitWidth());
Chandler Carrutha0796552012-03-12 11:19:31 +0000667
Benjamin Kramerc05aa952013-02-01 15:21:10 +0000668 Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
669 if (V->getType()->isVectorTy())
670 return ConstantVector::getSplat(V->getType()->getVectorNumElements(),
671 OffsetIntPtr);
672 return OffsetIntPtr;
Chandler Carrutha0796552012-03-12 11:19:31 +0000673}
674
Adrian Prantl5f8f34e42018-05-01 15:54:18 +0000675/// Compute the constant difference between two pointer values.
Chandler Carrutha0796552012-03-12 11:19:31 +0000676/// If the difference is not a constant, returns zero.
Mehdi Aminia28d91d2015-03-10 02:37:25 +0000677static Constant *computePointerDifference(const DataLayout &DL, Value *LHS,
678 Value *RHS) {
Rafael Espindola37dc9e12014-02-21 00:06:31 +0000679 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
680 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
Chandler Carrutha0796552012-03-12 11:19:31 +0000681
682 // If LHS and RHS are not related via constant offsets to the same base
683 // value, there is nothing we can do here.
684 if (LHS != RHS)
Craig Topper9f008862014-04-15 04:59:12 +0000685 return nullptr;
Chandler Carrutha0796552012-03-12 11:19:31 +0000686
687 // Otherwise, the difference of LHS - RHS can be computed as:
688 // LHS - RHS
689 // = (LHSOffset + Base) - (RHSOffset + Base)
690 // = LHSOffset - RHSOffset
691 return ConstantExpr::getSub(LHSOffset, RHSOffset);
692}
693
Sanjay Patel472cc782016-01-11 22:14:42 +0000694/// Given operands for a Sub, see if we can fold the result.
695/// If not, this returns null.
Duncan Sandsed6d6c32010-12-20 14:47:04 +0000696static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +0000697 const SimplifyQuery &Q, unsigned MaxRecurse) {
Sanjay Patel8b5ad3f2017-04-01 19:05:11 +0000698 if (Constant *C = foldOrCommuteConstant(Instruction::Sub, Op0, Op1, Q))
699 return C;
Duncan Sands0a2c41682010-12-15 14:07:39 +0000700
701 // X - undef -> undef
702 // undef - X -> undef
Duncan Sandsa29ea9a2011-02-01 09:06:20 +0000703 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
Duncan Sands0a2c41682010-12-15 14:07:39 +0000704 return UndefValue::get(Op0->getType());
705
706 // X - 0 -> X
707 if (match(Op1, m_Zero()))
708 return Op0;
709
710 // X - X -> 0
Duncan Sands772749a2011-01-01 20:08:02 +0000711 if (Op0 == Op1)
Duncan Sands0a2c41682010-12-15 14:07:39 +0000712 return Constant::getNullValue(Op0->getType());
713
Sanjay Patelefd88852016-10-19 21:23:45 +0000714 // Is this a negation?
715 if (match(Op0, m_Zero())) {
716 // 0 - X -> 0 if the sub is NUW.
717 if (isNUW)
Sanjay Patel30be6652018-04-22 17:07:44 +0000718 return Constant::getNullValue(Op0->getType());
Sanjay Patelefd88852016-10-19 21:23:45 +0000719
Craig Topper8205a1a2017-05-24 16:53:07 +0000720 KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
Craig Topperb45eabc2017-04-26 16:39:58 +0000721 if (Known.Zero.isMaxSignedValue()) {
Sanjay Patelefd88852016-10-19 21:23:45 +0000722 // Op1 is either 0 or the minimum signed value. If the sub is NSW, then
723 // Op1 must be 0 because negating the minimum signed value is undefined.
724 if (isNSW)
Sanjay Patel30be6652018-04-22 17:07:44 +0000725 return Constant::getNullValue(Op0->getType());
Sanjay Patelefd88852016-10-19 21:23:45 +0000726
727 // 0 - X -> X if X is 0 or the minimum signed value.
728 return Op1;
729 }
730 }
David Majnemercd4fbcd2014-07-31 04:49:18 +0000731
Duncan Sands99589d02011-01-18 11:50:19 +0000732 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
733 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
Dinesh Dwivedi99281a02014-06-26 08:57:33 +0000734 Value *X = nullptr, *Y = nullptr, *Z = Op1;
Duncan Sands99589d02011-01-18 11:50:19 +0000735 if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
736 // See if "V === Y - Z" simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000737 if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
Duncan Sands99589d02011-01-18 11:50:19 +0000738 // It does! Now see if "X + V" simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000739 if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
Duncan Sands99589d02011-01-18 11:50:19 +0000740 // It does, we successfully reassociated!
741 ++NumReassoc;
742 return W;
743 }
744 // See if "V === X - Z" simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000745 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
Duncan Sands99589d02011-01-18 11:50:19 +0000746 // It does! Now see if "Y + V" simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000747 if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
Duncan Sands99589d02011-01-18 11:50:19 +0000748 // It does, we successfully reassociated!
749 ++NumReassoc;
750 return W;
751 }
752 }
Duncan Sandsd0eb6d32010-12-21 14:00:22 +0000753
Duncan Sands99589d02011-01-18 11:50:19 +0000754 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
755 // For example, X - (X + 1) -> -1
756 X = Op0;
757 if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
758 // See if "V === X - Y" simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000759 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
Duncan Sands99589d02011-01-18 11:50:19 +0000760 // It does! Now see if "V - Z" simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000761 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
Duncan Sands99589d02011-01-18 11:50:19 +0000762 // It does, we successfully reassociated!
763 ++NumReassoc;
764 return W;
765 }
766 // See if "V === X - Z" simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000767 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
Duncan Sands99589d02011-01-18 11:50:19 +0000768 // It does! Now see if "V - Y" simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000769 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
Duncan Sands99589d02011-01-18 11:50:19 +0000770 // It does, we successfully reassociated!
771 ++NumReassoc;
772 return W;
773 }
774 }
775
776 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
777 // For example, X - (X - Y) -> Y.
778 Z = Op0;
Duncan Sandsd6f1a952011-01-14 15:26:10 +0000779 if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
780 // See if "V === Z - X" simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000781 if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
Duncan Sands99589d02011-01-18 11:50:19 +0000782 // It does! Now see if "V + Y" simplifies.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000783 if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
Duncan Sandsd6f1a952011-01-14 15:26:10 +0000784 // It does, we successfully reassociated!
785 ++NumReassoc;
786 return W;
787 }
788
Duncan Sands395ac42d2012-03-13 14:07:05 +0000789 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
790 if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
791 match(Op1, m_Trunc(m_Value(Y))))
792 if (X->getType() == Y->getType())
793 // See if "V === X - Y" simplifies.
794 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
795 // It does! Now see if "trunc V" simplifies.
David Majnemer6774d612016-07-26 17:58:05 +0000796 if (Value *W = SimplifyCastInst(Instruction::Trunc, V, Op0->getType(),
797 Q, MaxRecurse - 1))
Duncan Sands395ac42d2012-03-13 14:07:05 +0000798 // It does, return the simplified "trunc V".
799 return W;
800
801 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
Dan Gohman18c77a12013-01-31 02:50:36 +0000802 if (match(Op0, m_PtrToInt(m_Value(X))) &&
Duncan Sands395ac42d2012-03-13 14:07:05 +0000803 match(Op1, m_PtrToInt(m_Value(Y))))
Rafael Espindola37dc9e12014-02-21 00:06:31 +0000804 if (Constant *Result = computePointerDifference(Q.DL, X, Y))
Duncan Sands395ac42d2012-03-13 14:07:05 +0000805 return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
806
Duncan Sands99589d02011-01-18 11:50:19 +0000807 // i1 sub -> xor.
Craig Topperfde47232017-07-09 07:04:03 +0000808 if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
Duncan Sandsb8cee002012-03-13 11:42:19 +0000809 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
Duncan Sands99589d02011-01-18 11:50:19 +0000810 return V;
811
Duncan Sands0a2c41682010-12-15 14:07:39 +0000812 // Threading Sub over selects and phi nodes is pointless, so don't bother.
813 // Threading over the select in "A - select(cond, B, C)" means evaluating
814 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
815 // only if B and C are equal. If B and C are equal then (since we assume
816 // that operands have already been simplified) "select(cond, B, C)" should
817 // have been simplified to the common value of B and C already. Analysing
818 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
819 // for threading over phi nodes.
820
Craig Topper9f008862014-04-15 04:59:12 +0000821 return nullptr;
Duncan Sands0a2c41682010-12-15 14:07:39 +0000822}
823
Duncan Sandsed6d6c32010-12-20 14:47:04 +0000824Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +0000825 const SimplifyQuery &Q) {
826 return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit);
827}
828
Sanjay Patel472cc782016-01-11 22:14:42 +0000829/// Given operands for a Mul, see if we can fold the result.
830/// If not, this returns null.
Daniel Berlin5e3fcb12017-04-26 04:09:56 +0000831static Value *SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
Duncan Sandsb8cee002012-03-13 11:42:19 +0000832 unsigned MaxRecurse) {
Sanjay Patel8b5ad3f2017-04-01 19:05:11 +0000833 if (Constant *C = foldOrCommuteConstant(Instruction::Mul, Op0, Op1, Q))
834 return C;
Duncan Sandsd0eb6d32010-12-21 14:00:22 +0000835
836 // X * undef -> 0
Duncan Sandsd0eb6d32010-12-21 14:00:22 +0000837 // X * 0 -> 0
Sanjay Patel30be6652018-04-22 17:07:44 +0000838 if (match(Op1, m_CombineOr(m_Undef(), m_Zero())))
839 return Constant::getNullValue(Op0->getType());
Duncan Sandsd0eb6d32010-12-21 14:00:22 +0000840
841 // X * 1 -> X
842 if (match(Op1, m_One()))
843 return Op0;
844
Duncan Sandsb67edc62011-01-30 18:03:50 +0000845 // (X / Y) * Y -> X if the division is exact.
Craig Topper9f008862014-04-15 04:59:12 +0000846 Value *X = nullptr;
Florian Hahn19f9e322018-08-17 14:39:04 +0000847 if (Q.IIQ.UseInstrInfo &&
848 (match(Op0,
849 m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
850 match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0)))))) // Y * (X / Y)
Benjamin Kramer9442cd02012-01-01 17:55:30 +0000851 return X;
Duncan Sandsb67edc62011-01-30 18:03:50 +0000852
Nick Lewyckyb89d9a42011-01-29 19:55:23 +0000853 // i1 mul -> and.
Craig Topperfde47232017-07-09 07:04:03 +0000854 if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
Duncan Sandsb8cee002012-03-13 11:42:19 +0000855 if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
Duncan Sandsfecc6422010-12-21 15:03:43 +0000856 return V;
Duncan Sandsd0eb6d32010-12-21 14:00:22 +0000857
858 // Try some generic simplifications for associative operations.
Duncan Sandsb8cee002012-03-13 11:42:19 +0000859 if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
Duncan Sandsd0eb6d32010-12-21 14:00:22 +0000860 MaxRecurse))
861 return V;
862
Dmitry Venikovd2257be2018-01-02 05:47:42 +0000863 // Mul distributes over Add. Try some generic simplifications based on this.
Duncan Sandsd0eb6d32010-12-21 14:00:22 +0000864 if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
Duncan Sandsb8cee002012-03-13 11:42:19 +0000865 Q, MaxRecurse))
Duncan Sandsd0eb6d32010-12-21 14:00:22 +0000866 return V;
867
868 // If the operation is with the result of a select instruction, check whether
869 // operating on either branch of the select always yields the same value.
870 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
Duncan Sandsb8cee002012-03-13 11:42:19 +0000871 if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
Duncan Sandsd0eb6d32010-12-21 14:00:22 +0000872 MaxRecurse))
873 return V;
874
875 // If the operation is with the result of a phi instruction, check whether
876 // operating on all incoming values of the phi always yields the same value.
877 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
Duncan Sandsb8cee002012-03-13 11:42:19 +0000878 if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
Duncan Sandsd0eb6d32010-12-21 14:00:22 +0000879 MaxRecurse))
880 return V;
881
Craig Topper9f008862014-04-15 04:59:12 +0000882 return nullptr;
Duncan Sandsd0eb6d32010-12-21 14:00:22 +0000883}
884
Daniel Berlin5e3fcb12017-04-26 04:09:56 +0000885Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
886 return ::SimplifyMulInst(Op0, Op1, Q, RecursionLimit);
887}
888
Sanjay Patel0cb2ee92017-03-06 19:08:35 +0000889/// Check for common or similar folds of integer division or integer remainder.
Sanjay Patelfa877fd2017-09-11 13:34:27 +0000890/// This applies to all 4 opcodes (sdiv/udiv/srem/urem).
Sanjay Patel0cb2ee92017-03-06 19:08:35 +0000891static Value *simplifyDivRem(Value *Op0, Value *Op1, bool IsDiv) {
892 Type *Ty = Op0->getType();
893
894 // X / undef -> undef
895 // X % undef -> undef
896 if (match(Op1, m_Undef()))
897 return Op1;
898
899 // X / 0 -> undef
900 // X % 0 -> undef
901 // We don't need to preserve faults!
902 if (match(Op1, m_Zero()))
903 return UndefValue::get(Ty);
904
Zvi Rackover51f0d642018-01-24 17:22:00 +0000905 // If any element of a constant divisor vector is zero or undef, the whole op
906 // is undef.
Sanjay Patel2b1f6f42017-03-09 16:20:52 +0000907 auto *Op1C = dyn_cast<Constant>(Op1);
908 if (Op1C && Ty->isVectorTy()) {
909 unsigned NumElts = Ty->getVectorNumElements();
910 for (unsigned i = 0; i != NumElts; ++i) {
911 Constant *Elt = Op1C->getAggregateElement(i);
Zvi Rackover51f0d642018-01-24 17:22:00 +0000912 if (Elt && (Elt->isNullValue() || isa<UndefValue>(Elt)))
Sanjay Patel2b1f6f42017-03-09 16:20:52 +0000913 return UndefValue::get(Ty);
914 }
915 }
916
Sanjay Patel0cb2ee92017-03-06 19:08:35 +0000917 // undef / X -> 0
918 // undef % X -> 0
919 if (match(Op0, m_Undef()))
920 return Constant::getNullValue(Ty);
921
922 // 0 / X -> 0
923 // 0 % X -> 0
924 if (match(Op0, m_Zero()))
Sanjay Patel30be6652018-04-22 17:07:44 +0000925 return Constant::getNullValue(Op0->getType());
Sanjay Patel0cb2ee92017-03-06 19:08:35 +0000926
927 // X / X -> 1
928 // X % X -> 0
929 if (Op0 == Op1)
930 return IsDiv ? ConstantInt::get(Ty, 1) : Constant::getNullValue(Ty);
931
932 // X / 1 -> X
933 // X % 1 -> 0
Sanjay Patel962a8432017-03-09 21:56:03 +0000934 // If this is a boolean op (single-bit element type), we can't have
935 // division-by-zero or remainder-by-zero, so assume the divisor is 1.
Sanjay Patel1e911fa2018-06-25 18:51:21 +0000936 // Similarly, if we're zero-extending a boolean divisor, then assume it's a 1.
937 Value *X;
938 if (match(Op1, m_One()) || Ty->isIntOrIntVectorTy(1) ||
939 (match(Op1, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)))
Sanjay Patel0cb2ee92017-03-06 19:08:35 +0000940 return IsDiv ? Op0 : Constant::getNullValue(Ty);
941
942 return nullptr;
943}
944
Sanjay Patelcca8f782017-09-14 14:09:11 +0000945/// Given a predicate and two operands, return true if the comparison is true.
946/// This is a helper for div/rem simplification where we return some other value
947/// when we can prove a relationship between the operands.
948static bool isICmpTrue(ICmpInst::Predicate Pred, Value *LHS, Value *RHS,
949 const SimplifyQuery &Q, unsigned MaxRecurse) {
950 Value *V = SimplifyICmpInst(Pred, LHS, RHS, Q, MaxRecurse);
951 Constant *C = dyn_cast_or_null<Constant>(V);
952 return (C && C->isAllOnesValue());
953}
954
955/// Return true if we can simplify X / Y to 0. Remainder can adapt that answer
956/// to simplify X % Y to X.
Sanjay Patel0d4fd5b2017-09-14 14:59:07 +0000957static bool isDivZero(Value *X, Value *Y, const SimplifyQuery &Q,
Sanjay Patelcca8f782017-09-14 14:09:11 +0000958 unsigned MaxRecurse, bool IsSigned) {
959 // Recursion is always used, so bail out at once if we already hit the limit.
960 if (!MaxRecurse--)
961 return false;
962
963 if (IsSigned) {
Sanjay Patel0d4fd5b2017-09-14 14:59:07 +0000964 // |X| / |Y| --> 0
965 //
966 // We require that 1 operand is a simple constant. That could be extended to
967 // 2 variables if we computed the sign bit for each.
968 //
969 // Make sure that a constant is not the minimum signed value because taking
970 // the abs() of that is undefined.
971 Type *Ty = X->getType();
972 const APInt *C;
973 if (match(X, m_APInt(C)) && !C->isMinSignedValue()) {
974 // Is the variable divisor magnitude always greater than the constant
975 // dividend magnitude?
976 // |Y| > |C| --> Y < -abs(C) or Y > abs(C)
977 Constant *PosDividendC = ConstantInt::get(Ty, C->abs());
978 Constant *NegDividendC = ConstantInt::get(Ty, -C->abs());
979 if (isICmpTrue(CmpInst::ICMP_SLT, Y, NegDividendC, Q, MaxRecurse) ||
980 isICmpTrue(CmpInst::ICMP_SGT, Y, PosDividendC, Q, MaxRecurse))
981 return true;
982 }
983 if (match(Y, m_APInt(C))) {
984 // Special-case: we can't take the abs() of a minimum signed value. If
985 // that's the divisor, then all we have to do is prove that the dividend
986 // is also not the minimum signed value.
987 if (C->isMinSignedValue())
988 return isICmpTrue(CmpInst::ICMP_NE, X, Y, Q, MaxRecurse);
989
990 // Is the variable dividend magnitude always less than the constant
991 // divisor magnitude?
992 // |X| < |C| --> X > -abs(C) and X < abs(C)
993 Constant *PosDivisorC = ConstantInt::get(Ty, C->abs());
994 Constant *NegDivisorC = ConstantInt::get(Ty, -C->abs());
995 if (isICmpTrue(CmpInst::ICMP_SGT, X, NegDivisorC, Q, MaxRecurse) &&
996 isICmpTrue(CmpInst::ICMP_SLT, X, PosDivisorC, Q, MaxRecurse))
997 return true;
998 }
Sanjay Patelcca8f782017-09-14 14:09:11 +0000999 return false;
1000 }
1001
1002 // IsSigned == false.
Sanjay Patel0d4fd5b2017-09-14 14:59:07 +00001003 // Is the dividend unsigned less than the divisor?
1004 return isICmpTrue(ICmpInst::ICMP_ULT, X, Y, Q, MaxRecurse);
Sanjay Patelcca8f782017-09-14 14:09:11 +00001005}
1006
Sanjay Patelfa877fd2017-09-11 13:34:27 +00001007/// These are simplifications common to SDiv and UDiv.
1008static Value *simplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001009 const SimplifyQuery &Q, unsigned MaxRecurse) {
Sanjay Patel8b5ad3f2017-04-01 19:05:11 +00001010 if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1011 return C;
Duncan Sands771e82a2011-01-28 16:51:11 +00001012
Sanjay Patel0cb2ee92017-03-06 19:08:35 +00001013 if (Value *V = simplifyDivRem(Op0, Op1, true))
1014 return V;
1015
Sanjay Patelcca8f782017-09-14 14:09:11 +00001016 bool IsSigned = Opcode == Instruction::SDiv;
Duncan Sands65995fa2011-01-28 18:50:50 +00001017
Duncan Sands771e82a2011-01-28 16:51:11 +00001018 // (X * Y) / Y -> X if the multiplication does not overflow.
Sanjay Patel33cb8452018-01-19 16:12:55 +00001019 Value *X;
1020 if (match(Op0, m_c_Mul(m_Value(X), m_Specific(Op1)))) {
1021 auto *Mul = cast<OverflowingBinaryOperator>(Op0);
1022 // If the Mul does not overflow, then we are good to go.
Florian Hahn19f9e322018-08-17 14:39:04 +00001023 if ((IsSigned && Q.IIQ.hasNoSignedWrap(Mul)) ||
1024 (!IsSigned && Q.IIQ.hasNoUnsignedWrap(Mul)))
Duncan Sands5747aba2011-02-02 20:52:00 +00001025 return X;
Sanjay Patel33cb8452018-01-19 16:12:55 +00001026 // If X has the form X = A / Y, then X * Y cannot overflow.
1027 if ((IsSigned && match(X, m_SDiv(m_Value(), m_Specific(Op1)))) ||
1028 (!IsSigned && match(X, m_UDiv(m_Value(), m_Specific(Op1)))))
1029 return X;
Duncan Sands771e82a2011-01-28 16:51:11 +00001030 }
1031
Duncan Sands65995fa2011-01-28 18:50:50 +00001032 // (X rem Y) / Y -> 0
Sanjay Patelcca8f782017-09-14 14:09:11 +00001033 if ((IsSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1034 (!IsSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
Duncan Sands65995fa2011-01-28 18:50:50 +00001035 return Constant::getNullValue(Op0->getType());
1036
David Majnemercb9d5962014-10-11 10:20:01 +00001037 // (X /u C1) /u C2 -> 0 if C1 * C2 overflow
1038 ConstantInt *C1, *C2;
Sanjay Patelcca8f782017-09-14 14:09:11 +00001039 if (!IsSigned && match(Op0, m_UDiv(m_Value(X), m_ConstantInt(C1))) &&
David Majnemercb9d5962014-10-11 10:20:01 +00001040 match(Op1, m_ConstantInt(C2))) {
1041 bool Overflow;
Craig Topper9b71a402017-04-19 21:09:45 +00001042 (void)C1->getValue().umul_ov(C2->getValue(), Overflow);
David Majnemercb9d5962014-10-11 10:20:01 +00001043 if (Overflow)
1044 return Constant::getNullValue(Op0->getType());
1045 }
1046
Duncan Sands65995fa2011-01-28 18:50:50 +00001047 // If the operation is with the result of a select instruction, check whether
1048 // operating on either branch of the select always yields the same value.
1049 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
Duncan Sandsb8cee002012-03-13 11:42:19 +00001050 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
Duncan Sands65995fa2011-01-28 18:50:50 +00001051 return V;
1052
1053 // If the operation is with the result of a phi instruction, check whether
1054 // operating on all incoming values of the phi always yields the same value.
1055 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
Duncan Sandsb8cee002012-03-13 11:42:19 +00001056 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
Duncan Sands65995fa2011-01-28 18:50:50 +00001057 return V;
1058
Sanjay Patelcca8f782017-09-14 14:09:11 +00001059 if (isDivZero(Op0, Op1, Q, MaxRecurse, IsSigned))
1060 return Constant::getNullValue(Op0->getType());
1061
Craig Topper9f008862014-04-15 04:59:12 +00001062 return nullptr;
Duncan Sands771e82a2011-01-28 16:51:11 +00001063}
1064
Sanjay Patelfa877fd2017-09-11 13:34:27 +00001065/// These are simplifications common to SRem and URem.
1066static Value *simplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001067 const SimplifyQuery &Q, unsigned MaxRecurse) {
Sanjay Patel8b5ad3f2017-04-01 19:05:11 +00001068 if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1069 return C;
Duncan Sandsa3e36992011-05-02 16:27:02 +00001070
Sanjay Patel0cb2ee92017-03-06 19:08:35 +00001071 if (Value *V = simplifyDivRem(Op0, Op1, false))
1072 return V;
Duncan Sandsa3e36992011-05-02 16:27:02 +00001073
David Majnemerb435a422014-09-17 04:16:35 +00001074 // (X % Y) % Y -> X % Y
1075 if ((Opcode == Instruction::SRem &&
1076 match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1077 (Opcode == Instruction::URem &&
1078 match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
David Majnemerac717f02014-09-17 03:34:34 +00001079 return Op0;
David Majnemerac717f02014-09-17 03:34:34 +00001080
Anton Bikineev82f61152018-01-23 09:27:47 +00001081 // (X << Y) % X -> 0
Florian Hahn19f9e322018-08-17 14:39:04 +00001082 if (Q.IIQ.UseInstrInfo &&
1083 ((Opcode == Instruction::SRem &&
1084 match(Op0, m_NSWShl(m_Specific(Op1), m_Value()))) ||
1085 (Opcode == Instruction::URem &&
1086 match(Op0, m_NUWShl(m_Specific(Op1), m_Value())))))
Anton Bikineev82f61152018-01-23 09:27:47 +00001087 return Constant::getNullValue(Op0->getType());
1088
Duncan Sandsa3e36992011-05-02 16:27:02 +00001089 // If the operation is with the result of a select instruction, check whether
1090 // operating on either branch of the select always yields the same value.
1091 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
Duncan Sandsb8cee002012-03-13 11:42:19 +00001092 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
Duncan Sandsa3e36992011-05-02 16:27:02 +00001093 return V;
1094
1095 // If the operation is with the result of a phi instruction, check whether
1096 // operating on all incoming values of the phi always yields the same value.
1097 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
Duncan Sandsb8cee002012-03-13 11:42:19 +00001098 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
Duncan Sandsa3e36992011-05-02 16:27:02 +00001099 return V;
1100
Sanjay Patelcca8f782017-09-14 14:09:11 +00001101 // If X / Y == 0, then X % Y == X.
1102 if (isDivZero(Op0, Op1, Q, MaxRecurse, Opcode == Instruction::SRem))
1103 return Op0;
Sanjay Patelfa877fd2017-09-11 13:34:27 +00001104
1105 return nullptr;
1106}
1107
1108/// Given operands for an SDiv, see if we can fold the result.
1109/// If not, this returns null.
1110static Value *SimplifySDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1111 unsigned MaxRecurse) {
Chen Zheng69bb0642018-07-21 12:27:54 +00001112 // If two operands are negated and no signed overflow, return -1.
1113 if (isKnownNegation(Op0, Op1, /*NeedNSW=*/true))
1114 return Constant::getAllOnesValue(Op0->getType());
1115
Sanjay Patelcca8f782017-09-14 14:09:11 +00001116 return simplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse);
Sanjay Patelfa877fd2017-09-11 13:34:27 +00001117}
1118
1119Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
1120 return ::SimplifySDivInst(Op0, Op1, Q, RecursionLimit);
1121}
1122
1123/// Given operands for a UDiv, see if we can fold the result.
1124/// If not, this returns null.
1125static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1126 unsigned MaxRecurse) {
Sanjay Patelcca8f782017-09-14 14:09:11 +00001127 return simplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse);
Sanjay Patelfa877fd2017-09-11 13:34:27 +00001128}
1129
1130Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
1131 return ::SimplifyUDivInst(Op0, Op1, Q, RecursionLimit);
1132}
1133
Sanjay Patel472cc782016-01-11 22:14:42 +00001134/// Given operands for an SRem, see if we can fold the result.
1135/// If not, this returns null.
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001136static Value *SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
Duncan Sandsb8cee002012-03-13 11:42:19 +00001137 unsigned MaxRecurse) {
Sanjay Patel2b7e3102018-06-26 15:32:54 +00001138 // If the divisor is 0, the result is undefined, so assume the divisor is -1.
1139 // srem Op0, (sext i1 X) --> srem Op0, -1 --> 0
1140 Value *X;
1141 if (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1))
1142 return ConstantInt::getNullValue(Op0->getType());
1143
Chen Zhengf801d0f2018-07-20 13:00:47 +00001144 // If the two operands are negated, return 0.
1145 if (isKnownNegation(Op0, Op1))
Chen Zheng69bb0642018-07-21 12:27:54 +00001146 return ConstantInt::getNullValue(Op0->getType());
Chen Zhengf801d0f2018-07-20 13:00:47 +00001147
Sanjay Patelcca8f782017-09-14 14:09:11 +00001148 return simplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse);
Duncan Sandsa3e36992011-05-02 16:27:02 +00001149}
1150
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001151Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
1152 return ::SimplifySRemInst(Op0, Op1, Q, RecursionLimit);
1153}
1154
Sanjay Patel472cc782016-01-11 22:14:42 +00001155/// Given operands for a URem, see if we can fold the result.
1156/// If not, this returns null.
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001157static Value *SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
Chad Rosierc24b86f2011-12-01 03:08:23 +00001158 unsigned MaxRecurse) {
Sanjay Patelcca8f782017-09-14 14:09:11 +00001159 return simplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse);
Duncan Sandsa3e36992011-05-02 16:27:02 +00001160}
1161
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001162Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
1163 return ::SimplifyURemInst(Op0, Op1, Q, RecursionLimit);
1164}
1165
Sanjay Patel472cc782016-01-11 22:14:42 +00001166/// Returns true if a shift by \c Amount always yields undef.
Benjamin Kramer5e1794e2014-01-24 17:09:53 +00001167static bool isUndefShift(Value *Amount) {
1168 Constant *C = dyn_cast<Constant>(Amount);
1169 if (!C)
1170 return false;
1171
1172 // X shift by undef -> undef because it may shift by the bitwidth.
1173 if (isa<UndefValue>(C))
1174 return true;
1175
1176 // Shifting by the bitwidth or more is undefined.
1177 if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
1178 if (CI->getValue().getLimitedValue() >=
1179 CI->getType()->getScalarSizeInBits())
1180 return true;
1181
1182 // If all lanes of a vector shift are undefined the whole shift is.
1183 if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) {
1184 for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I)
1185 if (!isUndefShift(C->getAggregateElement(I)))
1186 return false;
1187 return true;
1188 }
1189
1190 return false;
1191}
1192
Sanjay Patel472cc782016-01-11 22:14:42 +00001193/// Given operands for an Shl, LShr or AShr, see if we can fold the result.
1194/// If not, this returns null.
Sanjay Patel8b5ad3f2017-04-01 19:05:11 +00001195static Value *SimplifyShift(Instruction::BinaryOps Opcode, Value *Op0,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001196 Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse) {
Sanjay Patel8b5ad3f2017-04-01 19:05:11 +00001197 if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1198 return C;
Duncan Sands7f60dc12011-01-14 00:37:45 +00001199
Duncan Sands571fd9a2011-01-14 14:44:12 +00001200 // 0 shift by X -> 0
Duncan Sands7f60dc12011-01-14 00:37:45 +00001201 if (match(Op0, m_Zero()))
Sanjay Patel30be6652018-04-22 17:07:44 +00001202 return Constant::getNullValue(Op0->getType());
Duncan Sands7f60dc12011-01-14 00:37:45 +00001203
Duncan Sands571fd9a2011-01-14 14:44:12 +00001204 // X shift by 0 -> X
Sanjay Patelad0bfb82018-06-26 17:31:38 +00001205 // Shift-by-sign-extended bool must be shift-by-0 because shift-by-all-ones
1206 // would be poison.
1207 Value *X;
1208 if (match(Op1, m_Zero()) ||
1209 (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)))
Duncan Sands7f60dc12011-01-14 00:37:45 +00001210 return Op0;
1211
Benjamin Kramer5e1794e2014-01-24 17:09:53 +00001212 // Fold undefined shifts.
1213 if (isUndefShift(Op1))
1214 return UndefValue::get(Op0->getType());
Duncan Sands7f60dc12011-01-14 00:37:45 +00001215
Duncan Sands571fd9a2011-01-14 14:44:12 +00001216 // If the operation is with the result of a select instruction, check whether
1217 // operating on either branch of the select always yields the same value.
1218 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
Duncan Sandsb8cee002012-03-13 11:42:19 +00001219 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
Duncan Sands571fd9a2011-01-14 14:44:12 +00001220 return V;
1221
1222 // If the operation is with the result of a phi instruction, check whether
1223 // operating on all incoming values of the phi always yields the same value.
1224 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
Duncan Sandsb8cee002012-03-13 11:42:19 +00001225 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
Duncan Sands571fd9a2011-01-14 14:44:12 +00001226 return V;
1227
Sanjay Patel6786bc52016-05-10 20:46:54 +00001228 // If any bits in the shift amount make that value greater than or equal to
1229 // the number of bits in the type, the shift is undefined.
Craig Topper8205a1a2017-05-24 16:53:07 +00001230 KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1231 if (Known.One.getLimitedValue() >= Known.getBitWidth())
Sanjay Patel6786bc52016-05-10 20:46:54 +00001232 return UndefValue::get(Op0->getType());
1233
1234 // If all valid bits in the shift amount are known zero, the first operand is
1235 // unchanged.
Craig Topper8205a1a2017-05-24 16:53:07 +00001236 unsigned NumValidShiftBits = Log2_32_Ceil(Known.getBitWidth());
Craig Topper8df66c62017-05-12 17:20:30 +00001237 if (Known.countMinTrailingZeros() >= NumValidShiftBits)
Sanjay Patel6786bc52016-05-10 20:46:54 +00001238 return Op0;
1239
Craig Topper9f008862014-04-15 04:59:12 +00001240 return nullptr;
Duncan Sands571fd9a2011-01-14 14:44:12 +00001241}
1242
Adrian Prantl5f8f34e42018-05-01 15:54:18 +00001243/// Given operands for an Shl, LShr or AShr, see if we can
David Majnemerbf7550e2014-11-05 00:59:59 +00001244/// fold the result. If not, this returns null.
Sanjay Patel8b5ad3f2017-04-01 19:05:11 +00001245static Value *SimplifyRightShift(Instruction::BinaryOps Opcode, Value *Op0,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001246 Value *Op1, bool isExact, const SimplifyQuery &Q,
David Majnemerbf7550e2014-11-05 00:59:59 +00001247 unsigned MaxRecurse) {
1248 if (Value *V = SimplifyShift(Opcode, Op0, Op1, Q, MaxRecurse))
1249 return V;
1250
1251 // X >> X -> 0
1252 if (Op0 == Op1)
1253 return Constant::getNullValue(Op0->getType());
1254
David Majnemer65c52ae2014-12-17 01:54:33 +00001255 // undef >> X -> 0
1256 // undef >> X -> undef (if it's exact)
1257 if (match(Op0, m_Undef()))
1258 return isExact ? Op0 : Constant::getNullValue(Op0->getType());
1259
David Majnemerbf7550e2014-11-05 00:59:59 +00001260 // The low bit cannot be shifted out of an exact shift if it is set.
1261 if (isExact) {
Craig Topper8205a1a2017-05-24 16:53:07 +00001262 KnownBits Op0Known = computeKnownBits(Op0, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT);
Craig Topperb45eabc2017-04-26 16:39:58 +00001263 if (Op0Known.One[0])
David Majnemerbf7550e2014-11-05 00:59:59 +00001264 return Op0;
1265 }
1266
1267 return nullptr;
1268}
1269
Sanjay Patel472cc782016-01-11 22:14:42 +00001270/// Given operands for an Shl, see if we can fold the result.
1271/// If not, this returns null.
Chris Lattner9e4aa022011-02-09 17:15:04 +00001272static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001273 const SimplifyQuery &Q, unsigned MaxRecurse) {
Duncan Sandsb8cee002012-03-13 11:42:19 +00001274 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
Duncan Sands571fd9a2011-01-14 14:44:12 +00001275 return V;
1276
1277 // undef << X -> 0
David Majnemer65c52ae2014-12-17 01:54:33 +00001278 // undef << X -> undef if (if it's NSW/NUW)
Duncan Sandsa29ea9a2011-02-01 09:06:20 +00001279 if (match(Op0, m_Undef()))
David Majnemer65c52ae2014-12-17 01:54:33 +00001280 return isNSW || isNUW ? Op0 : Constant::getNullValue(Op0->getType());
Duncan Sands571fd9a2011-01-14 14:44:12 +00001281
Chris Lattner9e4aa022011-02-09 17:15:04 +00001282 // (X >> A) << A -> X
1283 Value *X;
Florian Hahn19f9e322018-08-17 14:39:04 +00001284 if (Q.IIQ.UseInstrInfo &&
1285 match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
Chris Lattner9e4aa022011-02-09 17:15:04 +00001286 return X;
Roman Lebedev26838022018-06-07 20:03:45 +00001287
1288 // shl nuw i8 C, %x -> C iff C has sign bit set.
1289 if (isNUW && match(Op0, m_Negative()))
1290 return Op0;
1291 // NOTE: could use computeKnownBits() / LazyValueInfo,
1292 // but the cost-benefit analysis suggests it isn't worth it.
1293
Craig Topper9f008862014-04-15 04:59:12 +00001294 return nullptr;
Duncan Sands7f60dc12011-01-14 00:37:45 +00001295}
1296
Chris Lattner9e4aa022011-02-09 17:15:04 +00001297Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001298 const SimplifyQuery &Q) {
1299 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit);
1300}
1301
Sanjay Patel472cc782016-01-11 22:14:42 +00001302/// Given operands for an LShr, see if we can fold the result.
1303/// If not, this returns null.
Chris Lattner9e4aa022011-02-09 17:15:04 +00001304static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001305 const SimplifyQuery &Q, unsigned MaxRecurse) {
David Majnemerbf7550e2014-11-05 00:59:59 +00001306 if (Value *V = SimplifyRightShift(Instruction::LShr, Op0, Op1, isExact, Q,
1307 MaxRecurse))
1308 return V;
David Majnemera80fed72013-07-09 22:01:22 +00001309
Chris Lattner9e4aa022011-02-09 17:15:04 +00001310 // (X << A) >> A -> X
1311 Value *X;
David Majnemer4f438372014-11-04 17:38:50 +00001312 if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1))))
Chris Lattner9e4aa022011-02-09 17:15:04 +00001313 return X;
Duncan Sandsd114ab32011-02-13 17:15:40 +00001314
Hiroshi Inoue02f79ea2018-08-01 04:40:32 +00001315 // ((X << A) | Y) >> A -> X if effective width of Y is not larger than A.
1316 // We can return X as we do in the above case since OR alters no bits in X.
1317 // SimplifyDemandedBits in InstCombine can do more general optimization for
1318 // bit manipulation. This pattern aims to provide opportunities for other
1319 // optimizers by supporting a simple but common case in InstSimplify.
1320 Value *Y;
1321 const APInt *ShRAmt, *ShLAmt;
1322 if (match(Op1, m_APInt(ShRAmt)) &&
1323 match(Op0, m_c_Or(m_NUWShl(m_Value(X), m_APInt(ShLAmt)), m_Value(Y))) &&
1324 *ShRAmt == *ShLAmt) {
1325 const KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1326 const unsigned Width = Op0->getType()->getScalarSizeInBits();
1327 const unsigned EffWidthY = Width - YKnown.countMinLeadingZeros();
Benjamin Kramerbae6aab2018-08-12 11:43:03 +00001328 if (ShRAmt->uge(EffWidthY))
Hiroshi Inoue02f79ea2018-08-01 04:40:32 +00001329 return X;
1330 }
1331
Craig Topper9f008862014-04-15 04:59:12 +00001332 return nullptr;
Duncan Sands7f60dc12011-01-14 00:37:45 +00001333}
1334
Chris Lattner9e4aa022011-02-09 17:15:04 +00001335Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001336 const SimplifyQuery &Q) {
1337 return ::SimplifyLShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1338}
1339
Sanjay Patel472cc782016-01-11 22:14:42 +00001340/// Given operands for an AShr, see if we can fold the result.
1341/// If not, this returns null.
Chris Lattner9e4aa022011-02-09 17:15:04 +00001342static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001343 const SimplifyQuery &Q, unsigned MaxRecurse) {
David Majnemerbf7550e2014-11-05 00:59:59 +00001344 if (Value *V = SimplifyRightShift(Instruction::AShr, Op0, Op1, isExact, Q,
1345 MaxRecurse))
Duncan Sands571fd9a2011-01-14 14:44:12 +00001346 return V;
Duncan Sands7f60dc12011-01-14 00:37:45 +00001347
Sanjay Pateladf6e882018-02-18 18:05:08 +00001348 // all ones >>a X -> -1
1349 // Do not return Op0 because it may contain undef elements if it's a vector.
Duncan Sands7f60dc12011-01-14 00:37:45 +00001350 if (match(Op0, m_AllOnes()))
Sanjay Pateladf6e882018-02-18 18:05:08 +00001351 return Constant::getAllOnesValue(Op0->getType());
Duncan Sands7f60dc12011-01-14 00:37:45 +00001352
Chris Lattner9e4aa022011-02-09 17:15:04 +00001353 // (X << A) >> A -> X
1354 Value *X;
Florian Hahn19f9e322018-08-17 14:39:04 +00001355 if (Q.IIQ.UseInstrInfo && match(Op0, m_NSWShl(m_Value(X), m_Specific(Op1))))
Chris Lattner9e4aa022011-02-09 17:15:04 +00001356 return X;
Duncan Sandsd114ab32011-02-13 17:15:40 +00001357
Suyog Sarda68862412014-07-17 06:28:15 +00001358 // Arithmetic shifting an all-sign-bit value is a no-op.
Daniel Jasperaec2fa32016-12-19 08:22:17 +00001359 unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
Suyog Sarda68862412014-07-17 06:28:15 +00001360 if (NumSignBits == Op0->getType()->getScalarSizeInBits())
1361 return Op0;
1362
Craig Topper9f008862014-04-15 04:59:12 +00001363 return nullptr;
Duncan Sands7f60dc12011-01-14 00:37:45 +00001364}
1365
Chris Lattner9e4aa022011-02-09 17:15:04 +00001366Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001367 const SimplifyQuery &Q) {
1368 return ::SimplifyAShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1369}
1370
Craig Topper348314d2017-05-26 22:42:34 +00001371/// Commuted variants are assumed to be handled by calling this function again
1372/// with the parameters swapped.
David Majnemer1af36e52014-12-06 10:51:40 +00001373static Value *simplifyUnsignedRangeCheck(ICmpInst *ZeroICmp,
Roman Lebedev6e2c5c82019-09-08 20:14:15 +00001374 ICmpInst *UnsignedICmp, bool IsAnd,
1375 const DataLayout &DL) {
David Majnemer1af36e52014-12-06 10:51:40 +00001376 Value *X, *Y;
1377
1378 ICmpInst::Predicate EqPred;
David Majnemerd5b3aa42014-12-08 18:30:43 +00001379 if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) ||
1380 !ICmpInst::isEquality(EqPred))
David Majnemer1af36e52014-12-06 10:51:40 +00001381 return nullptr;
1382
1383 ICmpInst::Predicate UnsignedPred;
1384 if (match(UnsignedICmp, m_ICmp(UnsignedPred, m_Value(X), m_Specific(Y))) &&
1385 ICmpInst::isUnsigned(UnsignedPred))
1386 ;
1387 else if (match(UnsignedICmp,
Sanjay Patel0c57de42018-06-20 14:22:49 +00001388 m_ICmp(UnsignedPred, m_Specific(Y), m_Value(X))) &&
David Majnemer1af36e52014-12-06 10:51:40 +00001389 ICmpInst::isUnsigned(UnsignedPred))
1390 UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred);
1391 else
1392 return nullptr;
1393
1394 // X < Y && Y != 0 --> X < Y
1395 // X < Y || Y != 0 --> Y != 0
1396 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE)
1397 return IsAnd ? UnsignedICmp : ZeroICmp;
1398
Roman Lebedev6e2c5c82019-09-08 20:14:15 +00001399 // X <= Y && Y != 0 --> X <= Y iff X != 0
1400 // X <= Y || Y != 0 --> Y != 0 iff X != 0
1401 if (UnsignedPred == ICmpInst::ICMP_ULE && EqPred == ICmpInst::ICMP_NE &&
1402 isKnownNonZero(X, DL))
1403 return IsAnd ? UnsignedICmp : ZeroICmp;
1404
1405 // X > Y && Y == 0 --> Y == 0 iff X != 0
1406 // X > Y || Y == 0 --> X > Y iff X != 0
1407 if (UnsignedPred == ICmpInst::ICMP_UGT && EqPred == ICmpInst::ICMP_EQ &&
1408 isKnownNonZero(X, DL))
1409 return IsAnd ? ZeroICmp : UnsignedICmp;
1410
David Majnemer1af36e52014-12-06 10:51:40 +00001411 // X >= Y || Y != 0 --> true
1412 // X >= Y || Y == 0 --> X >= Y
1413 if (UnsignedPred == ICmpInst::ICMP_UGE && !IsAnd) {
1414 if (EqPred == ICmpInst::ICMP_NE)
1415 return getTrue(UnsignedICmp->getType());
1416 return UnsignedICmp;
1417 }
1418
David Majnemerd5b3aa42014-12-08 18:30:43 +00001419 // X < Y && Y == 0 --> false
1420 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
1421 IsAnd)
1422 return getFalse(UnsignedICmp->getType());
1423
David Majnemer1af36e52014-12-06 10:51:40 +00001424 return nullptr;
1425}
1426
Sanjay Patel9b1b2de2016-12-06 19:05:46 +00001427/// Commuted variants are assumed to be handled by calling this function again
1428/// with the parameters swapped.
1429static Value *simplifyAndOfICmpsWithSameOperands(ICmpInst *Op0, ICmpInst *Op1) {
1430 ICmpInst::Predicate Pred0, Pred1;
1431 Value *A ,*B;
Sanjay Patel53697752016-12-06 22:09:52 +00001432 if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
1433 !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
Sanjay Patel9b1b2de2016-12-06 19:05:46 +00001434 return nullptr;
1435
1436 // We have (icmp Pred0, A, B) & (icmp Pred1, A, B).
1437 // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1438 // can eliminate Op1 from this 'and'.
1439 if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
1440 return Op0;
1441
1442 // Check for any combination of predicates that are guaranteed to be disjoint.
1443 if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
1444 (Pred0 == ICmpInst::ICMP_EQ && ICmpInst::isFalseWhenEqual(Pred1)) ||
1445 (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT) ||
1446 (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT))
1447 return getFalse(Op0->getType());
1448
1449 return nullptr;
1450}
1451
1452/// Commuted variants are assumed to be handled by calling this function again
1453/// with the parameters swapped.
Sanjay Patel142cb832017-05-04 18:19:17 +00001454static Value *simplifyOrOfICmpsWithSameOperands(ICmpInst *Op0, ICmpInst *Op1) {
1455 ICmpInst::Predicate Pred0, Pred1;
1456 Value *A ,*B;
1457 if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
1458 !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
1459 return nullptr;
1460
1461 // We have (icmp Pred0, A, B) | (icmp Pred1, A, B).
1462 // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1463 // can eliminate Op0 from this 'or'.
1464 if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
1465 return Op1;
1466
1467 // Check for any combination of predicates that cover the entire range of
1468 // possibilities.
1469 if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
1470 (Pred0 == ICmpInst::ICMP_NE && ICmpInst::isTrueWhenEqual(Pred1)) ||
1471 (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGE) ||
1472 (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGE))
1473 return getTrue(Op0->getType());
1474
1475 return nullptr;
1476}
1477
Sanjay Patel599e65b2017-05-07 15:11:40 +00001478/// Test if a pair of compares with a shared operand and 2 constants has an
1479/// empty set intersection, full set union, or if one compare is a superset of
1480/// the other.
1481static Value *simplifyAndOrOfICmpsWithConstants(ICmpInst *Cmp0, ICmpInst *Cmp1,
1482 bool IsAnd) {
1483 // Look for this pattern: {and/or} (icmp X, C0), (icmp X, C1)).
1484 if (Cmp0->getOperand(0) != Cmp1->getOperand(0))
1485 return nullptr;
1486
1487 const APInt *C0, *C1;
1488 if (!match(Cmp0->getOperand(1), m_APInt(C0)) ||
1489 !match(Cmp1->getOperand(1), m_APInt(C1)))
1490 return nullptr;
1491
1492 auto Range0 = ConstantRange::makeExactICmpRegion(Cmp0->getPredicate(), *C0);
1493 auto Range1 = ConstantRange::makeExactICmpRegion(Cmp1->getPredicate(), *C1);
1494
Sanjay Patel67454472017-05-08 16:35:02 +00001495 // For and-of-compares, check if the intersection is empty:
Sanjay Patel599e65b2017-05-07 15:11:40 +00001496 // (icmp X, C0) && (icmp X, C1) --> empty set --> false
1497 if (IsAnd && Range0.intersectWith(Range1).isEmptySet())
1498 return getFalse(Cmp0->getType());
1499
1500 // For or-of-compares, check if the union is full:
1501 // (icmp X, C0) || (icmp X, C1) --> full set --> true
1502 if (!IsAnd && Range0.unionWith(Range1).isFullSet())
1503 return getTrue(Cmp0->getType());
1504
1505 // Is one range a superset of the other?
1506 // If this is and-of-compares, take the smaller set:
1507 // (icmp sgt X, 4) && (icmp sgt X, 42) --> icmp sgt X, 42
1508 // If this is or-of-compares, take the larger set:
1509 // (icmp sgt X, 4) || (icmp sgt X, 42) --> icmp sgt X, 4
1510 if (Range0.contains(Range1))
1511 return IsAnd ? Cmp1 : Cmp0;
1512 if (Range1.contains(Range0))
1513 return IsAnd ? Cmp0 : Cmp1;
1514
1515 return nullptr;
1516}
1517
Sanjay Patel6ef6aa92018-01-11 23:27:37 +00001518static Value *simplifyAndOrOfICmpsWithZero(ICmpInst *Cmp0, ICmpInst *Cmp1,
1519 bool IsAnd) {
1520 ICmpInst::Predicate P0 = Cmp0->getPredicate(), P1 = Cmp1->getPredicate();
1521 if (!match(Cmp0->getOperand(1), m_Zero()) ||
1522 !match(Cmp1->getOperand(1), m_Zero()) || P0 != P1)
1523 return nullptr;
1524
1525 if ((IsAnd && P0 != ICmpInst::ICMP_NE) || (!IsAnd && P1 != ICmpInst::ICMP_EQ))
1526 return nullptr;
1527
Sanjay Patel4158eff2018-01-13 15:44:44 +00001528 // We have either "(X == 0 || Y == 0)" or "(X != 0 && Y != 0)".
Sanjay Patel6ef6aa92018-01-11 23:27:37 +00001529 Value *X = Cmp0->getOperand(0);
1530 Value *Y = Cmp1->getOperand(0);
1531
1532 // If one of the compares is a masked version of a (not) null check, then
Sanjay Patel4158eff2018-01-13 15:44:44 +00001533 // that compare implies the other, so we eliminate the other. Optionally, look
1534 // through a pointer-to-int cast to match a null check of a pointer type.
Sanjay Patel6ef6aa92018-01-11 23:27:37 +00001535
Sanjay Patel9568f422018-01-14 15:58:18 +00001536 // (X == 0) || (([ptrtoint] X & ?) == 0) --> ([ptrtoint] X & ?) == 0
1537 // (X == 0) || ((? & [ptrtoint] X) == 0) --> (? & [ptrtoint] X) == 0
1538 // (X != 0) && (([ptrtoint] X & ?) != 0) --> ([ptrtoint] X & ?) != 0
1539 // (X != 0) && ((? & [ptrtoint] X) != 0) --> (? & [ptrtoint] X) != 0
Sanjay Patel4158eff2018-01-13 15:44:44 +00001540 if (match(Y, m_c_And(m_Specific(X), m_Value())) ||
1541 match(Y, m_c_And(m_PtrToInt(m_Specific(X)), m_Value())))
Sanjay Patel6ef6aa92018-01-11 23:27:37 +00001542 return Cmp1;
1543
Sanjay Patel9568f422018-01-14 15:58:18 +00001544 // (([ptrtoint] Y & ?) == 0) || (Y == 0) --> ([ptrtoint] Y & ?) == 0
1545 // ((? & [ptrtoint] Y) == 0) || (Y == 0) --> (? & [ptrtoint] Y) == 0
1546 // (([ptrtoint] Y & ?) != 0) && (Y != 0) --> ([ptrtoint] Y & ?) != 0
1547 // ((? & [ptrtoint] Y) != 0) && (Y != 0) --> (? & [ptrtoint] Y) != 0
Sanjay Patel4158eff2018-01-13 15:44:44 +00001548 if (match(X, m_c_And(m_Specific(Y), m_Value())) ||
1549 match(X, m_c_And(m_PtrToInt(m_Specific(Y)), m_Value())))
Sanjay Patel6ef6aa92018-01-11 23:27:37 +00001550 return Cmp0;
1551
1552 return nullptr;
1553}
1554
Florian Hahn19f9e322018-08-17 14:39:04 +00001555static Value *simplifyAndOfICmpsWithAdd(ICmpInst *Op0, ICmpInst *Op1,
1556 const InstrInfoQuery &IIQ) {
Sanjay Patel599e65b2017-05-07 15:11:40 +00001557 // (icmp (add V, C0), C1) & (icmp V, C0)
Sanjay Patelb2332e12016-09-20 14:36:14 +00001558 ICmpInst::Predicate Pred0, Pred1;
Sanjay Patel9ad8fb62016-06-20 20:59:59 +00001559 const APInt *C0, *C1;
Sanjay Patelb2332e12016-09-20 14:36:14 +00001560 Value *V;
Sanjay Patel1b312ad2016-09-28 13:53:13 +00001561 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
Sanjay Patelf8ee0e02016-06-19 17:20:27 +00001562 return nullptr;
David Majnemera315bd82014-09-15 08:15:28 +00001563
Sanjay Patel1b312ad2016-09-28 13:53:13 +00001564 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
David Majnemera315bd82014-09-15 08:15:28 +00001565 return nullptr;
1566
Florian Hahn19f9e322018-08-17 14:39:04 +00001567 auto *AddInst = cast<OverflowingBinaryOperator>(Op0->getOperand(0));
Sanjay Patel1b312ad2016-09-28 13:53:13 +00001568 if (AddInst->getOperand(1) != Op1->getOperand(1))
1569 return nullptr;
1570
Craig Topper9bce1ad2017-05-26 19:04:02 +00001571 Type *ITy = Op0->getType();
Florian Hahn19f9e322018-08-17 14:39:04 +00001572 bool isNSW = IIQ.hasNoSignedWrap(AddInst);
1573 bool isNUW = IIQ.hasNoUnsignedWrap(AddInst);
David Majnemera315bd82014-09-15 08:15:28 +00001574
Sanjay Patel1b312ad2016-09-28 13:53:13 +00001575 const APInt Delta = *C1 - *C0;
1576 if (C0->isStrictlyPositive()) {
David Majnemera315bd82014-09-15 08:15:28 +00001577 if (Delta == 2) {
1578 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
1579 return getFalse(ITy);
1580 if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1581 return getFalse(ITy);
1582 }
1583 if (Delta == 1) {
1584 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
1585 return getFalse(ITy);
1586 if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1587 return getFalse(ITy);
1588 }
1589 }
Sanjay Patel1b312ad2016-09-28 13:53:13 +00001590 if (C0->getBoolValue() && isNUW) {
David Majnemera315bd82014-09-15 08:15:28 +00001591 if (Delta == 2)
1592 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
1593 return getFalse(ITy);
1594 if (Delta == 1)
1595 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
1596 return getFalse(ITy);
1597 }
1598
1599 return nullptr;
1600}
1601
Florian Hahn19f9e322018-08-17 14:39:04 +00001602static Value *simplifyAndOfICmps(ICmpInst *Op0, ICmpInst *Op1,
Roman Lebedev6e2c5c82019-09-08 20:14:15 +00001603 const InstrInfoQuery &IIQ,
1604 const DataLayout &DL) {
1605 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/true, DL))
Craig Topper348314d2017-05-26 22:42:34 +00001606 return X;
Roman Lebedev6e2c5c82019-09-08 20:14:15 +00001607 if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/true, DL))
Sanjay Patel142cb832017-05-04 18:19:17 +00001608 return X;
1609
Craig Topper348314d2017-05-26 22:42:34 +00001610 if (Value *X = simplifyAndOfICmpsWithSameOperands(Op0, Op1))
1611 return X;
1612 if (Value *X = simplifyAndOfICmpsWithSameOperands(Op1, Op0))
Sanjay Patel142cb832017-05-04 18:19:17 +00001613 return X;
1614
Craig Topper348314d2017-05-26 22:42:34 +00001615 if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, true))
Sanjay Patel599e65b2017-05-07 15:11:40 +00001616 return X;
1617
Sanjay Patel6ef6aa92018-01-11 23:27:37 +00001618 if (Value *X = simplifyAndOrOfICmpsWithZero(Op0, Op1, true))
1619 return X;
1620
Florian Hahn19f9e322018-08-17 14:39:04 +00001621 if (Value *X = simplifyAndOfICmpsWithAdd(Op0, Op1, IIQ))
Craig Topper348314d2017-05-26 22:42:34 +00001622 return X;
Florian Hahn19f9e322018-08-17 14:39:04 +00001623 if (Value *X = simplifyAndOfICmpsWithAdd(Op1, Op0, IIQ))
Craig Topper348314d2017-05-26 22:42:34 +00001624 return X;
1625
1626 return nullptr;
1627}
1628
Florian Hahn19f9e322018-08-17 14:39:04 +00001629static Value *simplifyOrOfICmpsWithAdd(ICmpInst *Op0, ICmpInst *Op1,
1630 const InstrInfoQuery &IIQ) {
Sanjay Patel142cb832017-05-04 18:19:17 +00001631 // (icmp (add V, C0), C1) | (icmp V, C0)
1632 ICmpInst::Predicate Pred0, Pred1;
1633 const APInt *C0, *C1;
1634 Value *V;
1635 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
1636 return nullptr;
1637
1638 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
1639 return nullptr;
1640
1641 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1642 if (AddInst->getOperand(1) != Op1->getOperand(1))
1643 return nullptr;
1644
1645 Type *ITy = Op0->getType();
Florian Hahn19f9e322018-08-17 14:39:04 +00001646 bool isNSW = IIQ.hasNoSignedWrap(AddInst);
1647 bool isNUW = IIQ.hasNoUnsignedWrap(AddInst);
Sanjay Patel142cb832017-05-04 18:19:17 +00001648
1649 const APInt Delta = *C1 - *C0;
1650 if (C0->isStrictlyPositive()) {
1651 if (Delta == 2) {
1652 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE)
1653 return getTrue(ITy);
1654 if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1655 return getTrue(ITy);
1656 }
1657 if (Delta == 1) {
1658 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE)
1659 return getTrue(ITy);
1660 if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1661 return getTrue(ITy);
1662 }
1663 }
1664 if (C0->getBoolValue() && isNUW) {
1665 if (Delta == 2)
1666 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE)
1667 return getTrue(ITy);
1668 if (Delta == 1)
1669 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE)
1670 return getTrue(ITy);
1671 }
1672
1673 return nullptr;
1674}
1675
Florian Hahn19f9e322018-08-17 14:39:04 +00001676static Value *simplifyOrOfICmps(ICmpInst *Op0, ICmpInst *Op1,
Roman Lebedev6e2c5c82019-09-08 20:14:15 +00001677 const InstrInfoQuery &IIQ,
1678 const DataLayout &DL) {
1679 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/false, DL))
Craig Topper348314d2017-05-26 22:42:34 +00001680 return X;
Roman Lebedev6e2c5c82019-09-08 20:14:15 +00001681 if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/false, DL))
Craig Topper348314d2017-05-26 22:42:34 +00001682 return X;
Sanjay Patele42b4d52017-05-04 19:51:34 +00001683
Craig Topper348314d2017-05-26 22:42:34 +00001684 if (Value *X = simplifyOrOfICmpsWithSameOperands(Op0, Op1))
1685 return X;
1686 if (Value *X = simplifyOrOfICmpsWithSameOperands(Op1, Op0))
1687 return X;
1688
1689 if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, false))
1690 return X;
1691
Sanjay Patel6ef6aa92018-01-11 23:27:37 +00001692 if (Value *X = simplifyAndOrOfICmpsWithZero(Op0, Op1, false))
1693 return X;
1694
Florian Hahn19f9e322018-08-17 14:39:04 +00001695 if (Value *X = simplifyOrOfICmpsWithAdd(Op0, Op1, IIQ))
Craig Topper348314d2017-05-26 22:42:34 +00001696 return X;
Florian Hahn19f9e322018-08-17 14:39:04 +00001697 if (Value *X = simplifyOrOfICmpsWithAdd(Op1, Op0, IIQ))
Craig Topper348314d2017-05-26 22:42:34 +00001698 return X;
Sanjay Patele42b4d52017-05-04 19:51:34 +00001699
1700 return nullptr;
1701}
1702
Matt Arsenaultd54b7f02018-08-09 22:40:08 +00001703static Value *simplifyAndOrOfFCmps(const TargetLibraryInfo *TLI,
1704 FCmpInst *LHS, FCmpInst *RHS, bool IsAnd) {
Sanjay Pateleb731b02017-11-19 15:34:27 +00001705 Value *LHS0 = LHS->getOperand(0), *LHS1 = LHS->getOperand(1);
1706 Value *RHS0 = RHS->getOperand(0), *RHS1 = RHS->getOperand(1);
1707 if (LHS0->getType() != RHS0->getType())
1708 return nullptr;
1709
1710 FCmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
1711 if ((PredL == FCmpInst::FCMP_ORD && PredR == FCmpInst::FCMP_ORD && IsAnd) ||
1712 (PredL == FCmpInst::FCMP_UNO && PredR == FCmpInst::FCMP_UNO && !IsAnd)) {
1713 // (fcmp ord NNAN, X) & (fcmp ord X, Y) --> fcmp ord X, Y
1714 // (fcmp ord NNAN, X) & (fcmp ord Y, X) --> fcmp ord Y, X
1715 // (fcmp ord X, NNAN) & (fcmp ord X, Y) --> fcmp ord X, Y
1716 // (fcmp ord X, NNAN) & (fcmp ord Y, X) --> fcmp ord Y, X
1717 // (fcmp uno NNAN, X) | (fcmp uno X, Y) --> fcmp uno X, Y
1718 // (fcmp uno NNAN, X) | (fcmp uno Y, X) --> fcmp uno Y, X
1719 // (fcmp uno X, NNAN) | (fcmp uno X, Y) --> fcmp uno X, Y
1720 // (fcmp uno X, NNAN) | (fcmp uno Y, X) --> fcmp uno Y, X
Matt Arsenaultd54b7f02018-08-09 22:40:08 +00001721 if ((isKnownNeverNaN(LHS0, TLI) && (LHS1 == RHS0 || LHS1 == RHS1)) ||
1722 (isKnownNeverNaN(LHS1, TLI) && (LHS0 == RHS0 || LHS0 == RHS1)))
Sanjay Pateleb731b02017-11-19 15:34:27 +00001723 return RHS;
1724
1725 // (fcmp ord X, Y) & (fcmp ord NNAN, X) --> fcmp ord X, Y
1726 // (fcmp ord Y, X) & (fcmp ord NNAN, X) --> fcmp ord Y, X
1727 // (fcmp ord X, Y) & (fcmp ord X, NNAN) --> fcmp ord X, Y
1728 // (fcmp ord Y, X) & (fcmp ord X, NNAN) --> fcmp ord Y, X
1729 // (fcmp uno X, Y) | (fcmp uno NNAN, X) --> fcmp uno X, Y
1730 // (fcmp uno Y, X) | (fcmp uno NNAN, X) --> fcmp uno Y, X
1731 // (fcmp uno X, Y) | (fcmp uno X, NNAN) --> fcmp uno X, Y
1732 // (fcmp uno Y, X) | (fcmp uno X, NNAN) --> fcmp uno Y, X
Matt Arsenaultd54b7f02018-08-09 22:40:08 +00001733 if ((isKnownNeverNaN(RHS0, TLI) && (RHS1 == LHS0 || RHS1 == LHS1)) ||
1734 (isKnownNeverNaN(RHS1, TLI) && (RHS0 == LHS0 || RHS0 == LHS1)))
Sanjay Pateleb731b02017-11-19 15:34:27 +00001735 return LHS;
1736 }
1737
1738 return nullptr;
1739}
1740
Florian Hahn19f9e322018-08-17 14:39:04 +00001741static Value *simplifyAndOrOfCmps(const SimplifyQuery &Q,
Matt Arsenaultd54b7f02018-08-09 22:40:08 +00001742 Value *Op0, Value *Op1, bool IsAnd) {
Sanjay Patele42b4d52017-05-04 19:51:34 +00001743 // Look through casts of the 'and' operands to find compares.
1744 auto *Cast0 = dyn_cast<CastInst>(Op0);
1745 auto *Cast1 = dyn_cast<CastInst>(Op1);
1746 if (Cast0 && Cast1 && Cast0->getOpcode() == Cast1->getOpcode() &&
1747 Cast0->getSrcTy() == Cast1->getSrcTy()) {
1748 Op0 = Cast0->getOperand(0);
1749 Op1 = Cast1->getOperand(0);
1750 }
1751
Sanjay Pateleb731b02017-11-19 15:34:27 +00001752 Value *V = nullptr;
1753 auto *ICmp0 = dyn_cast<ICmpInst>(Op0);
1754 auto *ICmp1 = dyn_cast<ICmpInst>(Op1);
1755 if (ICmp0 && ICmp1)
Roman Lebedev6e2c5c82019-09-08 20:14:15 +00001756 V = IsAnd ? simplifyAndOfICmps(ICmp0, ICmp1, Q.IIQ, Q.DL)
1757 : simplifyOrOfICmps(ICmp0, ICmp1, Q.IIQ, Q.DL);
Sanjay Patele42b4d52017-05-04 19:51:34 +00001758
Sanjay Pateleb731b02017-11-19 15:34:27 +00001759 auto *FCmp0 = dyn_cast<FCmpInst>(Op0);
1760 auto *FCmp1 = dyn_cast<FCmpInst>(Op1);
1761 if (FCmp0 && FCmp1)
Florian Hahn19f9e322018-08-17 14:39:04 +00001762 V = simplifyAndOrOfFCmps(Q.TLI, FCmp0, FCmp1, IsAnd);
Sanjay Pateleb731b02017-11-19 15:34:27 +00001763
Craig Topper348314d2017-05-26 22:42:34 +00001764 if (!V)
1765 return nullptr;
1766 if (!Cast0)
Sanjay Patele42b4d52017-05-04 19:51:34 +00001767 return V;
Craig Topper348314d2017-05-26 22:42:34 +00001768
1769 // If we looked through casts, we can only handle a constant simplification
1770 // because we are not allowed to create a cast instruction here.
1771 if (auto *C = dyn_cast<Constant>(V))
1772 return ConstantExpr::getCast(Cast0->getOpcode(), C, Cast0->getType());
Sanjay Patele42b4d52017-05-04 19:51:34 +00001773
1774 return nullptr;
1775}
1776
Roman Lebedevc5847862019-08-29 12:48:04 +00001777/// Check that the Op1 is in expected form, i.e.:
1778/// %Agg = tail call { i4, i1 } @llvm.[us]mul.with.overflow.i4(i4 %X, i4 %???)
1779/// %Op1 = extractvalue { i4, i1 } %Agg, 1
1780static bool omitCheckForZeroBeforeMulWithOverflowInternal(Value *Op1,
1781 Value *X) {
1782 auto *Extract = dyn_cast<ExtractValueInst>(Op1);
1783 // We should only be extracting the overflow bit.
1784 if (!Extract || !Extract->getIndices().equals(1))
1785 return false;
1786 Value *Agg = Extract->getAggregateOperand();
1787 // This should be a multiplication-with-overflow intrinsic.
1788 if (!match(Agg, m_CombineOr(m_Intrinsic<Intrinsic::umul_with_overflow>(),
1789 m_Intrinsic<Intrinsic::smul_with_overflow>())))
1790 return false;
1791 // One of its multipliers should be the value we checked for zero before.
1792 if (!match(Agg, m_CombineOr(m_Argument<0>(m_Specific(X)),
1793 m_Argument<1>(m_Specific(X)))))
1794 return false;
1795 return true;
1796}
1797
Roman Lebedevaaf6ab42019-08-29 12:47:50 +00001798/// The @llvm.[us]mul.with.overflow intrinsic could have been folded from some
1799/// other form of check, e.g. one that was using division; it may have been
1800/// guarded against division-by-zero. We can drop that check now.
1801/// Look for:
1802/// %Op0 = icmp ne i4 %X, 0
1803/// %Agg = tail call { i4, i1 } @llvm.[us]mul.with.overflow.i4(i4 %X, i4 %???)
1804/// %Op1 = extractvalue { i4, i1 } %Agg, 1
1805/// %??? = and i1 %Op0, %Op1
1806/// We can just return %Op1
1807static Value *omitCheckForZeroBeforeMulWithOverflow(Value *Op0, Value *Op1) {
1808 ICmpInst::Predicate Pred;
1809 Value *X;
1810 if (!match(Op0, m_ICmp(Pred, m_Value(X), m_Zero())) ||
1811 Pred != ICmpInst::Predicate::ICMP_NE)
1812 return nullptr;
Roman Lebedevc5847862019-08-29 12:48:04 +00001813 // Is Op1 in expected form?
1814 if (!omitCheckForZeroBeforeMulWithOverflowInternal(Op1, X))
Roman Lebedevaaf6ab42019-08-29 12:47:50 +00001815 return nullptr;
1816 // Can omit 'and', and just return the overflow bit.
1817 return Op1;
1818}
1819
Roman Lebedevc5847862019-08-29 12:48:04 +00001820/// The @llvm.[us]mul.with.overflow intrinsic could have been folded from some
1821/// other form of check, e.g. one that was using division; it may have been
1822/// guarded against division-by-zero. We can drop that check now.
1823/// Look for:
1824/// %Op0 = icmp eq i4 %X, 0
1825/// %Agg = tail call { i4, i1 } @llvm.[us]mul.with.overflow.i4(i4 %X, i4 %???)
1826/// %Op1 = extractvalue { i4, i1 } %Agg, 1
1827/// %NotOp1 = xor i1 %Op1, true
1828/// %or = or i1 %Op0, %NotOp1
1829/// We can just return %NotOp1
1830static Value *omitCheckForZeroBeforeInvertedMulWithOverflow(Value *Op0,
1831 Value *NotOp1) {
1832 ICmpInst::Predicate Pred;
1833 Value *X;
1834 if (!match(Op0, m_ICmp(Pred, m_Value(X), m_Zero())) ||
1835 Pred != ICmpInst::Predicate::ICMP_EQ)
1836 return nullptr;
1837 // We expect the other hand of an 'or' to be a 'not'.
1838 Value *Op1;
1839 if (!match(NotOp1, m_Not(m_Value(Op1))))
1840 return nullptr;
1841 // Is Op1 in expected form?
1842 if (!omitCheckForZeroBeforeMulWithOverflowInternal(Op1, X))
1843 return nullptr;
1844 // Can omit 'and', and just return the inverted overflow bit.
1845 return NotOp1;
1846}
1847
Sanjay Patel472cc782016-01-11 22:14:42 +00001848/// Given operands for an And, see if we can fold the result.
1849/// If not, this returns null.
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00001850static Value *SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
Chad Rosierc24b86f2011-12-01 03:08:23 +00001851 unsigned MaxRecurse) {
Sanjay Patel8b5ad3f2017-04-01 19:05:11 +00001852 if (Constant *C = foldOrCommuteConstant(Instruction::And, Op0, Op1, Q))
1853 return C;
Duncan Sands7e800d62010-11-14 11:23:23 +00001854
Chris Lattnera71e9d62009-11-10 00:55:12 +00001855 // X & undef -> 0
Duncan Sandsa29ea9a2011-02-01 09:06:20 +00001856 if (match(Op1, m_Undef()))
Chris Lattnera71e9d62009-11-10 00:55:12 +00001857 return Constant::getNullValue(Op0->getType());
Duncan Sands7e800d62010-11-14 11:23:23 +00001858
Chris Lattnera71e9d62009-11-10 00:55:12 +00001859 // X & X = X
Duncan Sands772749a2011-01-01 20:08:02 +00001860 if (Op0 == Op1)
Chris Lattnera71e9d62009-11-10 00:55:12 +00001861 return Op0;
Duncan Sands7e800d62010-11-14 11:23:23 +00001862
Duncan Sandsc89ac072010-11-17 18:52:15 +00001863 // X & 0 = 0
1864 if (match(Op1, m_Zero()))
Sanjay Patel30be6652018-04-22 17:07:44 +00001865 return Constant::getNullValue(Op0->getType());
Duncan Sands7e800d62010-11-14 11:23:23 +00001866
Duncan Sandsc89ac072010-11-17 18:52:15 +00001867 // X & -1 = X
1868 if (match(Op1, m_AllOnes()))
1869 return Op0;
Duncan Sands7e800d62010-11-14 11:23:23 +00001870
Chris Lattnera71e9d62009-11-10 00:55:12 +00001871 // A & ~A = ~A & A = 0
Chris Lattner9e4aa022011-02-09 17:15:04 +00001872 if (match(Op0, m_Not(m_Specific(Op1))) ||
1873 match(Op1, m_Not(m_Specific(Op0))))
Chris Lattnera71e9d62009-11-10 00:55:12 +00001874 return Constant::getNullValue(Op0->getType());
Duncan Sands7e800d62010-11-14 11:23:23 +00001875
Chris Lattnera71e9d62009-11-10 00:55:12 +00001876 // (A | ?) & A = A
Craig Topperdad7d8d2017-07-16 06:57:41 +00001877 if (match(Op0, m_c_Or(m_Specific(Op1), m_Value())))
Chris Lattnera71e9d62009-11-10 00:55:12 +00001878 return Op1;
Duncan Sands7e800d62010-11-14 11:23:23 +00001879
Chris Lattnera71e9d62009-11-10 00:55:12 +00001880 // A & (A | ?) = A
Craig Topperdad7d8d2017-07-16 06:57:41 +00001881 if (match(Op1, m_c_Or(m_Specific(Op0), m_Value())))
Chris Lattnera71e9d62009-11-10 00:55:12 +00001882 return Op0;
Duncan Sands7e800d62010-11-14 11:23:23 +00001883
Sanjay Patel877364f2017-05-16 21:51:04 +00001884 // A mask that only clears known zeros of a shifted value is a no-op.
1885 Value *X;
1886 const APInt *Mask;
1887 const APInt *ShAmt;
1888 if (match(Op1, m_APInt(Mask))) {
1889 // If all bits in the inverted and shifted mask are clear:
1890 // and (shl X, ShAmt), Mask --> shl X, ShAmt
1891 if (match(Op0, m_Shl(m_Value(X), m_APInt(ShAmt))) &&
1892 (~(*Mask)).lshr(*ShAmt).isNullValue())
1893 return Op0;
1894
1895 // If all bits in the inverted and shifted mask are clear:
1896 // and (lshr X, ShAmt), Mask --> lshr X, ShAmt
1897 if (match(Op0, m_LShr(m_Value(X), m_APInt(ShAmt))) &&
1898 (~(*Mask)).shl(*ShAmt).isNullValue())
1899 return Op0;
1900 }
1901
Roman Lebedevaaf6ab42019-08-29 12:47:50 +00001902 // If we have a multiplication overflow check that is being 'and'ed with a
1903 // check that one of the multipliers is not zero, we can omit the 'and', and
1904 // only keep the overflow check.
1905 if (Value *V = omitCheckForZeroBeforeMulWithOverflow(Op0, Op1))
1906 return V;
1907 if (Value *V = omitCheckForZeroBeforeMulWithOverflow(Op1, Op0))
1908 return V;
1909
Duncan Sandsba286d72011-10-26 20:55:21 +00001910 // A & (-A) = A if A is a power of two or zero.
1911 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1912 match(Op1, m_Neg(m_Specific(Op0)))) {
Daniel Jasperaec2fa32016-12-19 08:22:17 +00001913 if (isKnownToBeAPowerOfTwo(Op0, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1914 Q.DT))
Duncan Sandsba286d72011-10-26 20:55:21 +00001915 return Op0;
Daniel Jasperaec2fa32016-12-19 08:22:17 +00001916 if (isKnownToBeAPowerOfTwo(Op1, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1917 Q.DT))
Duncan Sandsba286d72011-10-26 20:55:21 +00001918 return Op1;
1919 }
1920
Sanjay Patelb342f022019-06-20 22:55:28 +00001921 // This is a similar pattern used for checking if a value is a power-of-2:
1922 // (A - 1) & A --> 0 (if A is a power-of-2 or 0)
1923 // A & (A - 1) --> 0 (if A is a power-of-2 or 0)
1924 if (match(Op0, m_Add(m_Specific(Op1), m_AllOnes())) &&
1925 isKnownToBeAPowerOfTwo(Op1, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI, Q.DT))
1926 return Constant::getNullValue(Op1->getType());
1927 if (match(Op1, m_Add(m_Specific(Op0), m_AllOnes())) &&
1928 isKnownToBeAPowerOfTwo(Op0, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI, Q.DT))
1929 return Constant::getNullValue(Op0->getType());
1930
Florian Hahn19f9e322018-08-17 14:39:04 +00001931 if (Value *V = simplifyAndOrOfCmps(Q, Op0, Op1, true))
Sanjay Patele42b4d52017-05-04 19:51:34 +00001932 return V;
Sanjay Patel9ad8fb62016-06-20 20:59:59 +00001933
Duncan Sands6c7a52c2010-12-21 08:49:00 +00001934 // Try some generic simplifications for associative operations.
Duncan Sandsb8cee002012-03-13 11:42:19 +00001935 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1936 MaxRecurse))
Duncan Sands6c7a52c2010-12-21 08:49:00 +00001937 return V;
Benjamin Kramer8c35fb02010-09-10 22:39:55 +00001938
Duncan Sandsee3ec6e2010-12-21 13:32:22 +00001939 // And distributes over Or. Try some generic simplifications based on this.
1940 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
Duncan Sandsb8cee002012-03-13 11:42:19 +00001941 Q, MaxRecurse))
Duncan Sandsee3ec6e2010-12-21 13:32:22 +00001942 return V;
1943
1944 // And distributes over Xor. Try some generic simplifications based on this.
1945 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
Duncan Sandsb8cee002012-03-13 11:42:19 +00001946 Q, MaxRecurse))
Duncan Sandsee3ec6e2010-12-21 13:32:22 +00001947 return V;
1948
Duncan Sandsb0579e92010-11-10 13:00:08 +00001949 // If the operation is with the result of a select instruction, check whether
1950 // operating on either branch of the select always yields the same value.
Duncan Sandsf64e6902010-12-21 09:09:15 +00001951 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
Duncan Sandsb8cee002012-03-13 11:42:19 +00001952 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1953 MaxRecurse))
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00001954 return V;
1955
1956 // If the operation is with the result of a phi instruction, check whether
1957 // operating on all incoming values of the phi always yields the same value.
Duncan Sandsf64e6902010-12-21 09:09:15 +00001958 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
Duncan Sandsb8cee002012-03-13 11:42:19 +00001959 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
Duncan Sandsf64e6902010-12-21 09:09:15 +00001960 MaxRecurse))
Duncan Sandsb0579e92010-11-10 13:00:08 +00001961 return V;
1962
Hiroshi Inoue73f8b252018-08-03 05:39:48 +00001963 // Assuming the effective width of Y is not larger than A, i.e. all bits
1964 // from X and Y are disjoint in (X << A) | Y,
1965 // if the mask of this AND op covers all bits of X or Y, while it covers
1966 // no bits from the other, we can bypass this AND op. E.g.,
1967 // ((X << A) | Y) & Mask -> Y,
1968 // if Mask = ((1 << effective_width_of(Y)) - 1)
1969 // ((X << A) | Y) & Mask -> X << A,
1970 // if Mask = ((1 << effective_width_of(X)) - 1) << A
1971 // SimplifyDemandedBits in InstCombine can optimize the general case.
1972 // This pattern aims to help other passes for a common case.
1973 Value *Y, *XShifted;
1974 if (match(Op1, m_APInt(Mask)) &&
1975 match(Op0, m_c_Or(m_CombineAnd(m_NUWShl(m_Value(X), m_APInt(ShAmt)),
1976 m_Value(XShifted)),
1977 m_Value(Y)))) {
Hiroshi Inoue73f8b252018-08-03 05:39:48 +00001978 const unsigned Width = Op0->getType()->getScalarSizeInBits();
Benjamin Kramerbae6aab2018-08-12 11:43:03 +00001979 const unsigned ShftCnt = ShAmt->getLimitedValue(Width);
1980 const KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
Hiroshi Inoue73f8b252018-08-03 05:39:48 +00001981 const unsigned EffWidthY = Width - YKnown.countMinLeadingZeros();
1982 if (EffWidthY <= ShftCnt) {
1983 const KnownBits XKnown = computeKnownBits(X, Q.DL, 0, Q.AC, Q.CxtI,
1984 Q.DT);
1985 const unsigned EffWidthX = Width - XKnown.countMinLeadingZeros();
1986 const APInt EffBitsY = APInt::getLowBitsSet(Width, EffWidthY);
1987 const APInt EffBitsX = APInt::getLowBitsSet(Width, EffWidthX) << ShftCnt;
1988 // If the mask is extracting all bits from X or Y as is, we can skip
1989 // this AND op.
1990 if (EffBitsY.isSubsetOf(*Mask) && !EffBitsX.intersects(*Mask))
1991 return Y;
1992 if (EffBitsX.isSubsetOf(*Mask) && !EffBitsY.intersects(*Mask))
1993 return XShifted;
1994 }
1995 }
1996
Craig Topper9f008862014-04-15 04:59:12 +00001997 return nullptr;
Chris Lattner084a1b52009-11-09 22:57:59 +00001998}
1999
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00002000Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
2001 return ::SimplifyAndInst(Op0, Op1, Q, RecursionLimit);
2002}
2003
Sanjay Patel472cc782016-01-11 22:14:42 +00002004/// Given operands for an Or, see if we can fold the result.
2005/// If not, this returns null.
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00002006static Value *SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
Duncan Sandsb8cee002012-03-13 11:42:19 +00002007 unsigned MaxRecurse) {
Sanjay Patel8b5ad3f2017-04-01 19:05:11 +00002008 if (Constant *C = foldOrCommuteConstant(Instruction::Or, Op0, Op1, Q))
2009 return C;
Duncan Sands7e800d62010-11-14 11:23:23 +00002010
Chris Lattnera71e9d62009-11-10 00:55:12 +00002011 // X | undef -> -1
Sanjay Pateladf6e882018-02-18 18:05:08 +00002012 // X | -1 = -1
2013 // Do not return Op1 because it may contain undef elements if it's a vector.
2014 if (match(Op1, m_Undef()) || match(Op1, m_AllOnes()))
Chris Lattnera71e9d62009-11-10 00:55:12 +00002015 return Constant::getAllOnesValue(Op0->getType());
Duncan Sands7e800d62010-11-14 11:23:23 +00002016
Chris Lattnera71e9d62009-11-10 00:55:12 +00002017 // X | X = X
Duncan Sandsc89ac072010-11-17 18:52:15 +00002018 // X | 0 = X
Sanjay Pateladf6e882018-02-18 18:05:08 +00002019 if (Op0 == Op1 || match(Op1, m_Zero()))
Chris Lattnera71e9d62009-11-10 00:55:12 +00002020 return Op0;
Duncan Sands7e800d62010-11-14 11:23:23 +00002021
Chris Lattnera71e9d62009-11-10 00:55:12 +00002022 // A | ~A = ~A | A = -1
Chris Lattner9e4aa022011-02-09 17:15:04 +00002023 if (match(Op0, m_Not(m_Specific(Op1))) ||
2024 match(Op1, m_Not(m_Specific(Op0))))
Chris Lattnera71e9d62009-11-10 00:55:12 +00002025 return Constant::getAllOnesValue(Op0->getType());
Duncan Sands7e800d62010-11-14 11:23:23 +00002026
Chris Lattnera71e9d62009-11-10 00:55:12 +00002027 // (A & ?) | A = A
Craig Topperdad7d8d2017-07-16 06:57:41 +00002028 if (match(Op0, m_c_And(m_Specific(Op1), m_Value())))
Chris Lattnera71e9d62009-11-10 00:55:12 +00002029 return Op1;
Duncan Sands7e800d62010-11-14 11:23:23 +00002030
Chris Lattnera71e9d62009-11-10 00:55:12 +00002031 // A | (A & ?) = A
Craig Topperdad7d8d2017-07-16 06:57:41 +00002032 if (match(Op1, m_c_And(m_Specific(Op0), m_Value())))
Chris Lattnera71e9d62009-11-10 00:55:12 +00002033 return Op0;
Duncan Sands7e800d62010-11-14 11:23:23 +00002034
Benjamin Kramer5b7a4e02011-02-20 15:20:01 +00002035 // ~(A & ?) | A = -1
Craig Topperdad7d8d2017-07-16 06:57:41 +00002036 if (match(Op0, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
Benjamin Kramer5b7a4e02011-02-20 15:20:01 +00002037 return Constant::getAllOnesValue(Op1->getType());
2038
2039 // A | ~(A & ?) = -1
Craig Topperdad7d8d2017-07-16 06:57:41 +00002040 if (match(Op1, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
Benjamin Kramer5b7a4e02011-02-20 15:20:01 +00002041 return Constant::getAllOnesValue(Op0->getType());
2042
Craig Topperdad7d8d2017-07-16 06:57:41 +00002043 Value *A, *B;
Sanjay Patel08892252017-04-24 18:24:36 +00002044 // (A & ~B) | (A ^ B) -> (A ^ B)
2045 // (~B & A) | (A ^ B) -> (A ^ B)
Craig Topper0b650d32017-04-25 17:01:32 +00002046 // (A & ~B) | (B ^ A) -> (B ^ A)
2047 // (~B & A) | (B ^ A) -> (B ^ A)
2048 if (match(Op1, m_Xor(m_Value(A), m_Value(B))) &&
2049 (match(Op0, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
2050 match(Op0, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
Sanjay Patel08892252017-04-24 18:24:36 +00002051 return Op1;
2052
2053 // Commute the 'or' operands.
2054 // (A ^ B) | (A & ~B) -> (A ^ B)
2055 // (A ^ B) | (~B & A) -> (A ^ B)
Craig Topper0b650d32017-04-25 17:01:32 +00002056 // (B ^ A) | (A & ~B) -> (B ^ A)
2057 // (B ^ A) | (~B & A) -> (B ^ A)
2058 if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
2059 (match(Op1, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
2060 match(Op1, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
Sanjay Patel08892252017-04-24 18:24:36 +00002061 return Op0;
2062
Craig Topper479daaf2017-05-14 07:54:43 +00002063 // (A & B) | (~A ^ B) -> (~A ^ B)
2064 // (B & A) | (~A ^ B) -> (~A ^ B)
2065 // (A & B) | (B ^ ~A) -> (B ^ ~A)
2066 // (B & A) | (B ^ ~A) -> (B ^ ~A)
2067 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
2068 (match(Op1, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
2069 match(Op1, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
2070 return Op1;
2071
2072 // (~A ^ B) | (A & B) -> (~A ^ B)
2073 // (~A ^ B) | (B & A) -> (~A ^ B)
2074 // (B ^ ~A) | (A & B) -> (B ^ ~A)
2075 // (B ^ ~A) | (B & A) -> (B ^ ~A)
2076 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
2077 (match(Op0, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
2078 match(Op0, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
2079 return Op0;
2080
Florian Hahn19f9e322018-08-17 14:39:04 +00002081 if (Value *V = simplifyAndOrOfCmps(Q, Op0, Op1, false))
Sanjay Patele42b4d52017-05-04 19:51:34 +00002082 return V;
David Majnemera315bd82014-09-15 08:15:28 +00002083
Roman Lebedevc5847862019-08-29 12:48:04 +00002084 // If we have a multiplication overflow check that is being 'and'ed with a
2085 // check that one of the multipliers is not zero, we can omit the 'and', and
2086 // only keep the overflow check.
2087 if (Value *V = omitCheckForZeroBeforeInvertedMulWithOverflow(Op0, Op1))
2088 return V;
2089 if (Value *V = omitCheckForZeroBeforeInvertedMulWithOverflow(Op1, Op0))
2090 return V;
2091
Duncan Sands6c7a52c2010-12-21 08:49:00 +00002092 // Try some generic simplifications for associative operations.
Duncan Sandsb8cee002012-03-13 11:42:19 +00002093 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
2094 MaxRecurse))
Duncan Sands6c7a52c2010-12-21 08:49:00 +00002095 return V;
Benjamin Kramer8c35fb02010-09-10 22:39:55 +00002096
Duncan Sandsee3ec6e2010-12-21 13:32:22 +00002097 // Or distributes over And. Try some generic simplifications based on this.
Duncan Sandsb8cee002012-03-13 11:42:19 +00002098 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
2099 MaxRecurse))
Duncan Sandsee3ec6e2010-12-21 13:32:22 +00002100 return V;
2101
Duncan Sandsb0579e92010-11-10 13:00:08 +00002102 // If the operation is with the result of a select instruction, check whether
2103 // operating on either branch of the select always yields the same value.
Duncan Sandsf64e6902010-12-21 09:09:15 +00002104 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
Duncan Sandsb8cee002012-03-13 11:42:19 +00002105 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
Duncan Sandsf64e6902010-12-21 09:09:15 +00002106 MaxRecurse))
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00002107 return V;
2108
Craig Topper50500d52017-05-26 05:16:20 +00002109 // (A & C1)|(B & C2)
Craig Topper1da22c32017-05-26 19:03:53 +00002110 const APInt *C1, *C2;
2111 if (match(Op0, m_And(m_Value(A), m_APInt(C1))) &&
2112 match(Op1, m_And(m_Value(B), m_APInt(C2)))) {
2113 if (*C1 == ~*C2) {
Nick Lewycky8561a492014-06-19 03:51:46 +00002114 // (A & C1)|(B & C2)
2115 // If we have: ((V + N) & C1) | (V & C2)
2116 // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
2117 // replace with V+N.
Craig Topperc8bebb12017-05-26 19:03:59 +00002118 Value *N;
Craig Topper1da22c32017-05-26 19:03:53 +00002119 if (C2->isMask() && // C2 == 0+1+
Craig Topperc8bebb12017-05-26 19:03:59 +00002120 match(A, m_c_Add(m_Specific(B), m_Value(N)))) {
Nick Lewycky8561a492014-06-19 03:51:46 +00002121 // Add commutes, try both ways.
Craig Topperc8bebb12017-05-26 19:03:59 +00002122 if (MaskedValueIsZero(N, *C2, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
Nick Lewycky8561a492014-06-19 03:51:46 +00002123 return A;
2124 }
2125 // Or commutes, try both ways.
Craig Topper1da22c32017-05-26 19:03:53 +00002126 if (C1->isMask() &&
Craig Topperc8bebb12017-05-26 19:03:59 +00002127 match(B, m_c_Add(m_Specific(A), m_Value(N)))) {
Nick Lewycky8561a492014-06-19 03:51:46 +00002128 // Add commutes, try both ways.
Craig Topperc8bebb12017-05-26 19:03:59 +00002129 if (MaskedValueIsZero(N, *C1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
Nick Lewycky8561a492014-06-19 03:51:46 +00002130 return B;
2131 }
2132 }
2133 }
2134
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00002135 // If the operation is with the result of a phi instruction, check whether
2136 // operating on all incoming values of the phi always yields the same value.
Duncan Sandsf64e6902010-12-21 09:09:15 +00002137 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
Duncan Sandsb8cee002012-03-13 11:42:19 +00002138 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
Duncan Sandsb0579e92010-11-10 13:00:08 +00002139 return V;
2140
Craig Topper9f008862014-04-15 04:59:12 +00002141 return nullptr;
Chris Lattnera71e9d62009-11-10 00:55:12 +00002142}
2143
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00002144Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
2145 return ::SimplifyOrInst(Op0, Op1, Q, RecursionLimit);
2146}
2147
Sanjay Patel472cc782016-01-11 22:14:42 +00002148/// Given operands for a Xor, see if we can fold the result.
2149/// If not, this returns null.
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00002150static Value *SimplifyXorInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
Duncan Sandsb8cee002012-03-13 11:42:19 +00002151 unsigned MaxRecurse) {
Sanjay Patel8b5ad3f2017-04-01 19:05:11 +00002152 if (Constant *C = foldOrCommuteConstant(Instruction::Xor, Op0, Op1, Q))
2153 return C;
Duncan Sandsc89ac072010-11-17 18:52:15 +00002154
2155 // A ^ undef -> undef
Duncan Sandsa29ea9a2011-02-01 09:06:20 +00002156 if (match(Op1, m_Undef()))
Duncan Sands019a4182010-12-15 11:02:22 +00002157 return Op1;
Duncan Sandsc89ac072010-11-17 18:52:15 +00002158
2159 // A ^ 0 = A
2160 if (match(Op1, m_Zero()))
2161 return Op0;
2162
Eli Friedmanad3cfe72011-08-17 19:31:49 +00002163 // A ^ A = 0
2164 if (Op0 == Op1)
2165 return Constant::getNullValue(Op0->getType());
2166
Duncan Sandsc89ac072010-11-17 18:52:15 +00002167 // A ^ ~A = ~A ^ A = -1
Chris Lattner9e4aa022011-02-09 17:15:04 +00002168 if (match(Op0, m_Not(m_Specific(Op1))) ||
2169 match(Op1, m_Not(m_Specific(Op0))))
Duncan Sandsc89ac072010-11-17 18:52:15 +00002170 return Constant::getAllOnesValue(Op0->getType());
2171
Duncan Sands6c7a52c2010-12-21 08:49:00 +00002172 // Try some generic simplifications for associative operations.
Duncan Sandsb8cee002012-03-13 11:42:19 +00002173 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
2174 MaxRecurse))
Duncan Sands6c7a52c2010-12-21 08:49:00 +00002175 return V;
Duncan Sandsc89ac072010-11-17 18:52:15 +00002176
Duncan Sandsb238de02010-11-19 09:20:39 +00002177 // Threading Xor over selects and phi nodes is pointless, so don't bother.
2178 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
2179 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
2180 // only if B and C are equal. If B and C are equal then (since we assume
2181 // that operands have already been simplified) "select(cond, B, C)" should
2182 // have been simplified to the common value of B and C already. Analysing
2183 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
2184 // for threading over phi nodes.
Duncan Sandsc89ac072010-11-17 18:52:15 +00002185
Craig Topper9f008862014-04-15 04:59:12 +00002186 return nullptr;
Duncan Sandsc89ac072010-11-17 18:52:15 +00002187}
2188
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00002189Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
2190 return ::SimplifyXorInst(Op0, Op1, Q, RecursionLimit);
2191}
2192
2193
Chris Lattner229907c2011-07-18 04:54:35 +00002194static Type *GetCompareTy(Value *Op) {
Chris Lattnerccfdceb2009-11-09 23:55:12 +00002195 return CmpInst::makeCmpResultType(Op->getType());
2196}
2197
Sanjay Patel472cc782016-01-11 22:14:42 +00002198/// Rummage around inside V looking for something equivalent to the comparison
2199/// "LHS Pred RHS". Return such a value if found, otherwise return null.
2200/// Helper function for analyzing max/min idioms.
Duncan Sandsaf327282011-05-07 16:56:49 +00002201static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
2202 Value *LHS, Value *RHS) {
2203 SelectInst *SI = dyn_cast<SelectInst>(V);
2204 if (!SI)
Craig Topper9f008862014-04-15 04:59:12 +00002205 return nullptr;
Duncan Sandsaf327282011-05-07 16:56:49 +00002206 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
2207 if (!Cmp)
Craig Topper9f008862014-04-15 04:59:12 +00002208 return nullptr;
Duncan Sandsaf327282011-05-07 16:56:49 +00002209 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
2210 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
2211 return Cmp;
2212 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
2213 LHS == CmpRHS && RHS == CmpLHS)
2214 return Cmp;
Craig Topper9f008862014-04-15 04:59:12 +00002215 return nullptr;
Duncan Sandsaf327282011-05-07 16:56:49 +00002216}
2217
Dan Gohman9631d902013-02-01 00:49:06 +00002218// A significant optimization not implemented here is assuming that alloca
2219// addresses are not equal to incoming argument values. They don't *alias*,
2220// as we say, but that doesn't mean they aren't equal, so we take a
2221// conservative approach.
2222//
2223// This is inspired in part by C++11 5.10p1:
2224// "Two pointers of the same type compare equal if and only if they are both
2225// null, both point to the same function, or both represent the same
2226// address."
2227//
2228// This is pretty permissive.
2229//
2230// It's also partly due to C11 6.5.9p6:
2231// "Two pointers compare equal if and only if both are null pointers, both are
2232// pointers to the same object (including a pointer to an object and a
2233// subobject at its beginning) or function, both are pointers to one past the
2234// last element of the same array object, or one is a pointer to one past the
2235// end of one array object and the other is a pointer to the start of a
NAKAMURA Takumi065fd352013-04-08 23:05:21 +00002236// different array object that happens to immediately follow the first array
Dan Gohman9631d902013-02-01 00:49:06 +00002237// object in the address space.)
2238//
2239// C11's version is more restrictive, however there's no reason why an argument
2240// couldn't be a one-past-the-end value for a stack object in the caller and be
2241// equal to the beginning of a stack object in the callee.
2242//
2243// If the C and C++ standards are ever made sufficiently restrictive in this
2244// area, it may be possible to update LLVM's semantics accordingly and reinstate
2245// this optimization.
Anna Thomas43d7e1c2016-05-03 14:58:21 +00002246static Constant *
2247computePointerICmp(const DataLayout &DL, const TargetLibraryInfo *TLI,
2248 const DominatorTree *DT, CmpInst::Predicate Pred,
Nuno Lopes404f1062017-09-09 18:23:11 +00002249 AssumptionCache *AC, const Instruction *CxtI,
Florian Hahn19f9e322018-08-17 14:39:04 +00002250 const InstrInfoQuery &IIQ, Value *LHS, Value *RHS) {
Dan Gohmanb3e2d3a2013-02-01 00:11:13 +00002251 // First, skip past any trivial no-ops.
2252 LHS = LHS->stripPointerCasts();
2253 RHS = RHS->stripPointerCasts();
2254
2255 // A non-null pointer is not equal to a null pointer.
Florian Hahn19f9e322018-08-17 14:39:04 +00002256 if (llvm::isKnownNonZero(LHS, DL, 0, nullptr, nullptr, nullptr,
2257 IIQ.UseInstrInfo) &&
2258 isa<ConstantPointerNull>(RHS) &&
Dan Gohmanb3e2d3a2013-02-01 00:11:13 +00002259 (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
2260 return ConstantInt::get(GetCompareTy(LHS),
2261 !CmpInst::isTrueWhenEqual(Pred));
2262
Chandler Carruth8059c842012-03-25 21:28:14 +00002263 // We can only fold certain predicates on pointer comparisons.
2264 switch (Pred) {
2265 default:
Craig Topper9f008862014-04-15 04:59:12 +00002266 return nullptr;
Chandler Carruth8059c842012-03-25 21:28:14 +00002267
2268 // Equality comaprisons are easy to fold.
2269 case CmpInst::ICMP_EQ:
2270 case CmpInst::ICMP_NE:
2271 break;
2272
2273 // We can only handle unsigned relational comparisons because 'inbounds' on
2274 // a GEP only protects against unsigned wrapping.
2275 case CmpInst::ICMP_UGT:
2276 case CmpInst::ICMP_UGE:
2277 case CmpInst::ICMP_ULT:
2278 case CmpInst::ICMP_ULE:
2279 // However, we have to switch them to their signed variants to handle
2280 // negative indices from the base pointer.
2281 Pred = ICmpInst::getSignedPredicate(Pred);
2282 break;
2283 }
2284
Dan Gohmanb3e2d3a2013-02-01 00:11:13 +00002285 // Strip off any constant offsets so that we can reason about them.
2286 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
2287 // here and compare base addresses like AliasAnalysis does, however there are
2288 // numerous hazards. AliasAnalysis and its utilities rely on special rules
2289 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
2290 // doesn't need to guarantee pointer inequality when it says NoAlias.
Rafael Espindola37dc9e12014-02-21 00:06:31 +00002291 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
2292 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
Chandler Carruth8059c842012-03-25 21:28:14 +00002293
Dan Gohmanb3e2d3a2013-02-01 00:11:13 +00002294 // If LHS and RHS are related via constant offsets to the same base
2295 // value, we can replace it with an icmp which just compares the offsets.
2296 if (LHS == RHS)
2297 return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
Chandler Carruth8059c842012-03-25 21:28:14 +00002298
Dan Gohmanb3e2d3a2013-02-01 00:11:13 +00002299 // Various optimizations for (in)equality comparisons.
2300 if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
2301 // Different non-empty allocations that exist at the same time have
2302 // different addresses (if the program can tell). Global variables always
2303 // exist, so they always exist during the lifetime of each other and all
2304 // allocas. Two different allocas usually have different addresses...
2305 //
2306 // However, if there's an @llvm.stackrestore dynamically in between two
2307 // allocas, they may have the same address. It's tempting to reduce the
2308 // scope of the problem by only looking at *static* allocas here. That would
2309 // cover the majority of allocas while significantly reducing the likelihood
2310 // of having an @llvm.stackrestore pop up in the middle. However, it's not
2311 // actually impossible for an @llvm.stackrestore to pop up in the middle of
2312 // an entry block. Also, if we have a block that's not attached to a
2313 // function, we can't tell if it's "static" under the current definition.
2314 // Theoretically, this problem could be fixed by creating a new kind of
2315 // instruction kind specifically for static allocas. Such a new instruction
2316 // could be required to be at the top of the entry block, thus preventing it
2317 // from being subject to a @llvm.stackrestore. Instcombine could even
2318 // convert regular allocas into these special allocas. It'd be nifty.
2319 // However, until then, this problem remains open.
2320 //
2321 // So, we'll assume that two non-empty allocas have different addresses
2322 // for now.
2323 //
2324 // With all that, if the offsets are within the bounds of their allocations
2325 // (and not one-past-the-end! so we can't use inbounds!), and their
2326 // allocations aren't the same, the pointers are not equal.
2327 //
2328 // Note that it's not necessary to check for LHS being a global variable
2329 // address, due to canonicalization and constant folding.
2330 if (isa<AllocaInst>(LHS) &&
2331 (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
Benjamin Kramerc05aa952013-02-01 15:21:10 +00002332 ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
2333 ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
Dan Gohmanb3e2d3a2013-02-01 00:11:13 +00002334 uint64_t LHSSize, RHSSize;
Manoj Gupta77eeac32018-07-09 22:27:23 +00002335 ObjectSizeOpts Opts;
2336 Opts.NullIsUnknownSize =
2337 NullPointerIsDefined(cast<AllocaInst>(LHS)->getFunction());
Benjamin Kramerc05aa952013-02-01 15:21:10 +00002338 if (LHSOffsetCI && RHSOffsetCI &&
Manoj Gupta77eeac32018-07-09 22:27:23 +00002339 getObjectSize(LHS, LHSSize, DL, TLI, Opts) &&
2340 getObjectSize(RHS, RHSSize, DL, TLI, Opts)) {
Benjamin Kramerc05aa952013-02-01 15:21:10 +00002341 const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
2342 const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
Dan Gohmanb3e2d3a2013-02-01 00:11:13 +00002343 if (!LHSOffsetValue.isNegative() &&
2344 !RHSOffsetValue.isNegative() &&
2345 LHSOffsetValue.ult(LHSSize) &&
2346 RHSOffsetValue.ult(RHSSize)) {
2347 return ConstantInt::get(GetCompareTy(LHS),
2348 !CmpInst::isTrueWhenEqual(Pred));
2349 }
2350 }
2351
2352 // Repeat the above check but this time without depending on DataLayout
2353 // or being able to compute a precise size.
2354 if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
2355 !cast<PointerType>(RHS->getType())->isEmptyTy() &&
2356 LHSOffset->isNullValue() &&
2357 RHSOffset->isNullValue())
2358 return ConstantInt::get(GetCompareTy(LHS),
2359 !CmpInst::isTrueWhenEqual(Pred));
2360 }
Benjamin Kramer942dfe62013-09-23 14:16:38 +00002361
2362 // Even if an non-inbounds GEP occurs along the path we can still optimize
2363 // equality comparisons concerning the result. We avoid walking the whole
2364 // chain again by starting where the last calls to
2365 // stripAndComputeConstantOffsets left off and accumulate the offsets.
Rafael Espindola37dc9e12014-02-21 00:06:31 +00002366 Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
2367 Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
Benjamin Kramer942dfe62013-09-23 14:16:38 +00002368 if (LHS == RHS)
2369 return ConstantExpr::getICmp(Pred,
2370 ConstantExpr::getAdd(LHSOffset, LHSNoBound),
2371 ConstantExpr::getAdd(RHSOffset, RHSNoBound));
Hal Finkelafcd8db2014-12-01 23:38:06 +00002372
2373 // If one side of the equality comparison must come from a noalias call
2374 // (meaning a system memory allocation function), and the other side must
2375 // come from a pointer that cannot overlap with dynamically-allocated
2376 // memory within the lifetime of the current function (allocas, byval
2377 // arguments, globals), then determine the comparison result here.
Bjorn Pettersson71e8c6f2019-04-24 06:55:50 +00002378 SmallVector<const Value *, 8> LHSUObjs, RHSUObjs;
Hal Finkelafcd8db2014-12-01 23:38:06 +00002379 GetUnderlyingObjects(LHS, LHSUObjs, DL);
2380 GetUnderlyingObjects(RHS, RHSUObjs, DL);
2381
2382 // Is the set of underlying objects all noalias calls?
Bjorn Pettersson71e8c6f2019-04-24 06:55:50 +00002383 auto IsNAC = [](ArrayRef<const Value *> Objects) {
David Majnemer0a16c222016-08-11 21:15:00 +00002384 return all_of(Objects, isNoAliasCall);
Hal Finkelafcd8db2014-12-01 23:38:06 +00002385 };
2386
2387 // Is the set of underlying objects all things which must be disjoint from
Hal Finkelaa19baf2014-12-04 17:45:19 +00002388 // noalias calls. For allocas, we consider only static ones (dynamic
2389 // allocas might be transformed into calls to malloc not simultaneously
2390 // live with the compared-to allocation). For globals, we exclude symbols
2391 // that might be resolve lazily to symbols in another dynamically-loaded
2392 // library (and, thus, could be malloc'ed by the implementation).
Bjorn Pettersson71e8c6f2019-04-24 06:55:50 +00002393 auto IsAllocDisjoint = [](ArrayRef<const Value *> Objects) {
2394 return all_of(Objects, [](const Value *V) {
Sanjay Patel34ea70a2016-01-11 22:24:35 +00002395 if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
2396 return AI->getParent() && AI->getFunction() && AI->isStaticAlloca();
2397 if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
2398 return (GV->hasLocalLinkage() || GV->hasHiddenVisibility() ||
Peter Collingbourne96efdd62016-06-14 21:01:22 +00002399 GV->hasProtectedVisibility() || GV->hasGlobalUnnamedAddr()) &&
Sanjay Patel34ea70a2016-01-11 22:24:35 +00002400 !GV->isThreadLocal();
2401 if (const Argument *A = dyn_cast<Argument>(V))
2402 return A->hasByValAttr();
2403 return false;
2404 });
Hal Finkelafcd8db2014-12-01 23:38:06 +00002405 };
2406
2407 if ((IsNAC(LHSUObjs) && IsAllocDisjoint(RHSUObjs)) ||
2408 (IsNAC(RHSUObjs) && IsAllocDisjoint(LHSUObjs)))
2409 return ConstantInt::get(GetCompareTy(LHS),
2410 !CmpInst::isTrueWhenEqual(Pred));
Anna Thomas43d7e1c2016-05-03 14:58:21 +00002411
2412 // Fold comparisons for non-escaping pointer even if the allocation call
2413 // cannot be elided. We cannot fold malloc comparison to null. Also, the
2414 // dynamic allocation call could be either of the operands.
2415 Value *MI = nullptr;
Nuno Lopes404f1062017-09-09 18:23:11 +00002416 if (isAllocLikeFn(LHS, TLI) &&
2417 llvm::isKnownNonZero(RHS, DL, 0, nullptr, CxtI, DT))
Anna Thomas43d7e1c2016-05-03 14:58:21 +00002418 MI = LHS;
Nuno Lopes404f1062017-09-09 18:23:11 +00002419 else if (isAllocLikeFn(RHS, TLI) &&
2420 llvm::isKnownNonZero(LHS, DL, 0, nullptr, CxtI, DT))
Anna Thomas43d7e1c2016-05-03 14:58:21 +00002421 MI = RHS;
2422 // FIXME: We should also fold the compare when the pointer escapes, but the
2423 // compare dominates the pointer escape
2424 if (MI && !PointerMayBeCaptured(MI, true, true))
2425 return ConstantInt::get(GetCompareTy(LHS),
2426 CmpInst::isFalseWhenEqual(Pred));
Dan Gohmanb3e2d3a2013-02-01 00:11:13 +00002427 }
2428
2429 // Otherwise, fail.
Craig Topper9f008862014-04-15 04:59:12 +00002430 return nullptr;
Chandler Carruth8059c842012-03-25 21:28:14 +00002431}
Chris Lattner01990f02012-02-24 19:01:58 +00002432
Sanjay Pateldc65a272016-12-03 17:30:22 +00002433/// Fold an icmp when its operands have i1 scalar type.
2434static Value *simplifyICmpOfBools(CmpInst::Predicate Pred, Value *LHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00002435 Value *RHS, const SimplifyQuery &Q) {
Sanjay Pateldc65a272016-12-03 17:30:22 +00002436 Type *ITy = GetCompareTy(LHS); // The return type.
2437 Type *OpTy = LHS->getType(); // The operand type.
Craig Topperfde47232017-07-09 07:04:03 +00002438 if (!OpTy->isIntOrIntVectorTy(1))
Sanjay Pateldc65a272016-12-03 17:30:22 +00002439 return nullptr;
2440
Sanjay Patele2787b92017-05-17 20:27:55 +00002441 // A boolean compared to true/false can be simplified in 14 out of the 20
2442 // (10 predicates * 2 constants) possible combinations. Cases not handled here
2443 // require a 'not' of the LHS, so those must be transformed in InstCombine.
2444 if (match(RHS, m_Zero())) {
2445 switch (Pred) {
2446 case CmpInst::ICMP_NE: // X != 0 -> X
2447 case CmpInst::ICMP_UGT: // X >u 0 -> X
2448 case CmpInst::ICMP_SLT: // X <s 0 -> X
2449 return LHS;
2450
2451 case CmpInst::ICMP_ULT: // X <u 0 -> false
2452 case CmpInst::ICMP_SGT: // X >s 0 -> false
2453 return getFalse(ITy);
2454
2455 case CmpInst::ICMP_UGE: // X >=u 0 -> true
2456 case CmpInst::ICMP_SLE: // X <=s 0 -> true
2457 return getTrue(ITy);
2458
2459 default: break;
2460 }
2461 } else if (match(RHS, m_One())) {
2462 switch (Pred) {
2463 case CmpInst::ICMP_EQ: // X == 1 -> X
2464 case CmpInst::ICMP_UGE: // X >=u 1 -> X
2465 case CmpInst::ICMP_SLE: // X <=s -1 -> X
2466 return LHS;
2467
2468 case CmpInst::ICMP_UGT: // X >u 1 -> false
2469 case CmpInst::ICMP_SLT: // X <s -1 -> false
2470 return getFalse(ITy);
2471
2472 case CmpInst::ICMP_ULE: // X <=u 1 -> true
2473 case CmpInst::ICMP_SGE: // X >=s -1 -> true
2474 return getTrue(ITy);
2475
2476 default: break;
2477 }
2478 }
2479
Sanjay Pateldc65a272016-12-03 17:30:22 +00002480 switch (Pred) {
2481 default:
2482 break;
Sanjay Pateldc65a272016-12-03 17:30:22 +00002483 case ICmpInst::ICMP_UGE:
Sanjay Pateldc65a272016-12-03 17:30:22 +00002484 if (isImpliedCondition(RHS, LHS, Q.DL).getValueOr(false))
2485 return getTrue(ITy);
2486 break;
2487 case ICmpInst::ICMP_SGE:
2488 /// For signed comparison, the values for an i1 are 0 and -1
2489 /// respectively. This maps into a truth table of:
2490 /// LHS | RHS | LHS >=s RHS | LHS implies RHS
2491 /// 0 | 0 | 1 (0 >= 0) | 1
2492 /// 0 | 1 | 1 (0 >= -1) | 1
2493 /// 1 | 0 | 0 (-1 >= 0) | 0
2494 /// 1 | 1 | 1 (-1 >= -1) | 1
2495 if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2496 return getTrue(ITy);
2497 break;
Sanjay Pateldc65a272016-12-03 17:30:22 +00002498 case ICmpInst::ICMP_ULE:
2499 if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2500 return getTrue(ITy);
2501 break;
2502 }
2503
2504 return nullptr;
2505}
2506
2507/// Try hard to fold icmp with zero RHS because this is a common case.
2508static Value *simplifyICmpWithZero(CmpInst::Predicate Pred, Value *LHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00002509 Value *RHS, const SimplifyQuery &Q) {
Sanjay Pateldc65a272016-12-03 17:30:22 +00002510 if (!match(RHS, m_Zero()))
2511 return nullptr;
2512
2513 Type *ITy = GetCompareTy(LHS); // The return type.
Sanjay Pateldc65a272016-12-03 17:30:22 +00002514 switch (Pred) {
2515 default:
2516 llvm_unreachable("Unknown ICmp predicate!");
2517 case ICmpInst::ICMP_ULT:
2518 return getFalse(ITy);
2519 case ICmpInst::ICMP_UGE:
2520 return getTrue(ITy);
2521 case ICmpInst::ICMP_EQ:
2522 case ICmpInst::ICMP_ULE:
Florian Hahn19f9e322018-08-17 14:39:04 +00002523 if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT, Q.IIQ.UseInstrInfo))
Sanjay Pateldc65a272016-12-03 17:30:22 +00002524 return getFalse(ITy);
2525 break;
2526 case ICmpInst::ICMP_NE:
2527 case ICmpInst::ICMP_UGT:
Florian Hahn19f9e322018-08-17 14:39:04 +00002528 if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT, Q.IIQ.UseInstrInfo))
Sanjay Pateldc65a272016-12-03 17:30:22 +00002529 return getTrue(ITy);
2530 break;
Craig Topper1a36b7d2017-05-15 06:39:41 +00002531 case ICmpInst::ICMP_SLT: {
2532 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2533 if (LHSKnown.isNegative())
Sanjay Pateldc65a272016-12-03 17:30:22 +00002534 return getTrue(ITy);
Craig Topper1a36b7d2017-05-15 06:39:41 +00002535 if (LHSKnown.isNonNegative())
Sanjay Pateldc65a272016-12-03 17:30:22 +00002536 return getFalse(ITy);
2537 break;
Craig Topper1a36b7d2017-05-15 06:39:41 +00002538 }
2539 case ICmpInst::ICMP_SLE: {
2540 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2541 if (LHSKnown.isNegative())
Sanjay Pateldc65a272016-12-03 17:30:22 +00002542 return getTrue(ITy);
Craig Topper1a36b7d2017-05-15 06:39:41 +00002543 if (LHSKnown.isNonNegative() &&
2544 isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
Sanjay Pateldc65a272016-12-03 17:30:22 +00002545 return getFalse(ITy);
2546 break;
Craig Topper1a36b7d2017-05-15 06:39:41 +00002547 }
2548 case ICmpInst::ICMP_SGE: {
2549 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2550 if (LHSKnown.isNegative())
Sanjay Pateldc65a272016-12-03 17:30:22 +00002551 return getFalse(ITy);
Craig Topper1a36b7d2017-05-15 06:39:41 +00002552 if (LHSKnown.isNonNegative())
Sanjay Pateldc65a272016-12-03 17:30:22 +00002553 return getTrue(ITy);
2554 break;
Craig Topper1a36b7d2017-05-15 06:39:41 +00002555 }
2556 case ICmpInst::ICMP_SGT: {
2557 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2558 if (LHSKnown.isNegative())
Sanjay Pateldc65a272016-12-03 17:30:22 +00002559 return getFalse(ITy);
Craig Topper1a36b7d2017-05-15 06:39:41 +00002560 if (LHSKnown.isNonNegative() &&
2561 isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
Sanjay Pateldc65a272016-12-03 17:30:22 +00002562 return getTrue(ITy);
2563 break;
2564 }
Craig Topper1a36b7d2017-05-15 06:39:41 +00002565 }
Sanjay Pateldc65a272016-12-03 17:30:22 +00002566
2567 return nullptr;
2568}
2569
Sanjay Patel67bde282016-08-22 23:12:02 +00002570static Value *simplifyICmpWithConstant(CmpInst::Predicate Pred, Value *LHS,
Florian Hahn19f9e322018-08-17 14:39:04 +00002571 Value *RHS, const InstrInfoQuery &IIQ) {
Roman Lebedev0c43d722018-03-15 16:17:40 +00002572 Type *ITy = GetCompareTy(RHS); // The return type.
2573
Roman Lebedev6aca3352018-03-15 16:17:46 +00002574 Value *X;
2575 // Sign-bit checks can be optimized to true/false after unsigned
2576 // floating-point casts:
2577 // icmp slt (bitcast (uitofp X)), 0 --> false
2578 // icmp sgt (bitcast (uitofp X)), -1 --> true
2579 if (match(LHS, m_BitCast(m_UIToFP(m_Value(X))))) {
2580 if (Pred == ICmpInst::ICMP_SLT && match(RHS, m_Zero()))
2581 return ConstantInt::getFalse(ITy);
2582 if (Pred == ICmpInst::ICMP_SGT && match(RHS, m_AllOnes()))
2583 return ConstantInt::getTrue(ITy);
2584 }
2585
Sanjay Patel200e3cb2016-08-23 17:30:56 +00002586 const APInt *C;
2587 if (!match(RHS, m_APInt(C)))
Sanjay Patel67bde282016-08-22 23:12:02 +00002588 return nullptr;
2589
2590 // Rule out tautological comparisons (eg., ult 0 or uge 0).
Sanjoy Das1f7b8132016-10-02 00:09:57 +00002591 ConstantRange RHS_CR = ConstantRange::makeExactICmpRegion(Pred, *C);
Sanjay Patel67bde282016-08-22 23:12:02 +00002592 if (RHS_CR.isEmptySet())
Roman Lebedev0c43d722018-03-15 16:17:40 +00002593 return ConstantInt::getFalse(ITy);
Sanjay Patel67bde282016-08-22 23:12:02 +00002594 if (RHS_CR.isFullSet())
Roman Lebedev0c43d722018-03-15 16:17:40 +00002595 return ConstantInt::getTrue(ITy);
Sanjay Patel200e3cb2016-08-23 17:30:56 +00002596
Nikita Popov49097592019-03-09 21:17:42 +00002597 ConstantRange LHS_CR = computeConstantRange(LHS, IIQ.UseInstrInfo);
Sanjay Patel67bde282016-08-22 23:12:02 +00002598 if (!LHS_CR.isFullSet()) {
2599 if (RHS_CR.contains(LHS_CR))
Roman Lebedev0c43d722018-03-15 16:17:40 +00002600 return ConstantInt::getTrue(ITy);
Sanjay Patel67bde282016-08-22 23:12:02 +00002601 if (RHS_CR.inverse().contains(LHS_CR))
Roman Lebedev0c43d722018-03-15 16:17:40 +00002602 return ConstantInt::getFalse(ITy);
Sanjay Patel67bde282016-08-22 23:12:02 +00002603 }
2604
2605 return nullptr;
2606}
2607
Sanjay Patel2df38a82017-05-08 16:21:55 +00002608/// TODO: A large part of this logic is duplicated in InstCombine's
2609/// foldICmpBinOp(). We should be able to share that and avoid the code
2610/// duplication.
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002611static Value *simplifyICmpWithBinOp(CmpInst::Predicate Pred, Value *LHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00002612 Value *RHS, const SimplifyQuery &Q,
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002613 unsigned MaxRecurse) {
2614 Type *ITy = GetCompareTy(LHS); // The return type.
2615
2616 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2617 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2618 if (MaxRecurse && (LBO || RBO)) {
2619 // Analyze the case when either LHS or RHS is an add instruction.
2620 Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
2621 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2622 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2623 if (LBO && LBO->getOpcode() == Instruction::Add) {
2624 A = LBO->getOperand(0);
2625 B = LBO->getOperand(1);
2626 NoLHSWrapProblem =
2627 ICmpInst::isEquality(Pred) ||
Florian Hahn19f9e322018-08-17 14:39:04 +00002628 (CmpInst::isUnsigned(Pred) &&
2629 Q.IIQ.hasNoUnsignedWrap(cast<OverflowingBinaryOperator>(LBO))) ||
2630 (CmpInst::isSigned(Pred) &&
2631 Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(LBO)));
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002632 }
2633 if (RBO && RBO->getOpcode() == Instruction::Add) {
2634 C = RBO->getOperand(0);
2635 D = RBO->getOperand(1);
2636 NoRHSWrapProblem =
2637 ICmpInst::isEquality(Pred) ||
Florian Hahn19f9e322018-08-17 14:39:04 +00002638 (CmpInst::isUnsigned(Pred) &&
2639 Q.IIQ.hasNoUnsignedWrap(cast<OverflowingBinaryOperator>(RBO))) ||
2640 (CmpInst::isSigned(Pred) &&
2641 Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(RBO)));
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002642 }
2643
2644 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2645 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2646 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2647 Constant::getNullValue(RHS->getType()), Q,
2648 MaxRecurse - 1))
2649 return V;
2650
2651 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2652 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2653 if (Value *V =
2654 SimplifyICmpInst(Pred, Constant::getNullValue(LHS->getType()),
2655 C == LHS ? D : C, Q, MaxRecurse - 1))
2656 return V;
2657
2658 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2659 if (A && C && (A == C || A == D || B == C || B == D) && NoLHSWrapProblem &&
2660 NoRHSWrapProblem) {
2661 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2662 Value *Y, *Z;
2663 if (A == C) {
2664 // C + B == C + D -> B == D
2665 Y = B;
2666 Z = D;
2667 } else if (A == D) {
2668 // D + B == C + D -> B == C
2669 Y = B;
2670 Z = C;
2671 } else if (B == C) {
2672 // A + C == C + D -> A == D
2673 Y = A;
2674 Z = D;
2675 } else {
2676 assert(B == D);
2677 // A + D == C + D -> A == C
2678 Y = A;
2679 Z = C;
2680 }
2681 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse - 1))
2682 return V;
2683 }
2684 }
2685
2686 {
2687 Value *Y = nullptr;
2688 // icmp pred (or X, Y), X
2689 if (LBO && match(LBO, m_c_Or(m_Value(Y), m_Specific(RHS)))) {
2690 if (Pred == ICmpInst::ICMP_ULT)
2691 return getFalse(ITy);
2692 if (Pred == ICmpInst::ICMP_UGE)
2693 return getTrue(ITy);
2694
2695 if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SGE) {
Craig Topper1a36b7d2017-05-15 06:39:41 +00002696 KnownBits RHSKnown = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2697 KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2698 if (RHSKnown.isNonNegative() && YKnown.isNegative())
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002699 return Pred == ICmpInst::ICMP_SLT ? getTrue(ITy) : getFalse(ITy);
Craig Topper1a36b7d2017-05-15 06:39:41 +00002700 if (RHSKnown.isNegative() || YKnown.isNonNegative())
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002701 return Pred == ICmpInst::ICMP_SLT ? getFalse(ITy) : getTrue(ITy);
2702 }
2703 }
2704 // icmp pred X, (or X, Y)
2705 if (RBO && match(RBO, m_c_Or(m_Value(Y), m_Specific(LHS)))) {
2706 if (Pred == ICmpInst::ICMP_ULE)
2707 return getTrue(ITy);
2708 if (Pred == ICmpInst::ICMP_UGT)
2709 return getFalse(ITy);
2710
2711 if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SLE) {
Craig Topper1a36b7d2017-05-15 06:39:41 +00002712 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2713 KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2714 if (LHSKnown.isNonNegative() && YKnown.isNegative())
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002715 return Pred == ICmpInst::ICMP_SGT ? getTrue(ITy) : getFalse(ITy);
Craig Topper1a36b7d2017-05-15 06:39:41 +00002716 if (LHSKnown.isNegative() || YKnown.isNonNegative())
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002717 return Pred == ICmpInst::ICMP_SGT ? getFalse(ITy) : getTrue(ITy);
2718 }
2719 }
2720 }
2721
2722 // icmp pred (and X, Y), X
Craig Topper72ee6942017-06-24 06:24:01 +00002723 if (LBO && match(LBO, m_c_And(m_Value(), m_Specific(RHS)))) {
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002724 if (Pred == ICmpInst::ICMP_UGT)
2725 return getFalse(ITy);
2726 if (Pred == ICmpInst::ICMP_ULE)
2727 return getTrue(ITy);
2728 }
2729 // icmp pred X, (and X, Y)
Craig Topper72ee6942017-06-24 06:24:01 +00002730 if (RBO && match(RBO, m_c_And(m_Value(), m_Specific(LHS)))) {
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002731 if (Pred == ICmpInst::ICMP_UGE)
2732 return getTrue(ITy);
2733 if (Pred == ICmpInst::ICMP_ULT)
2734 return getFalse(ITy);
2735 }
2736
2737 // 0 - (zext X) pred C
2738 if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
2739 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
2740 if (RHSC->getValue().isStrictlyPositive()) {
2741 if (Pred == ICmpInst::ICMP_SLT)
2742 return ConstantInt::getTrue(RHSC->getContext());
2743 if (Pred == ICmpInst::ICMP_SGE)
2744 return ConstantInt::getFalse(RHSC->getContext());
2745 if (Pred == ICmpInst::ICMP_EQ)
2746 return ConstantInt::getFalse(RHSC->getContext());
2747 if (Pred == ICmpInst::ICMP_NE)
2748 return ConstantInt::getTrue(RHSC->getContext());
2749 }
2750 if (RHSC->getValue().isNonNegative()) {
2751 if (Pred == ICmpInst::ICMP_SLE)
2752 return ConstantInt::getTrue(RHSC->getContext());
2753 if (Pred == ICmpInst::ICMP_SGT)
2754 return ConstantInt::getFalse(RHSC->getContext());
2755 }
2756 }
2757 }
2758
2759 // icmp pred (urem X, Y), Y
2760 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002761 switch (Pred) {
2762 default:
2763 break;
2764 case ICmpInst::ICMP_SGT:
Craig Topper1a36b7d2017-05-15 06:39:41 +00002765 case ICmpInst::ICMP_SGE: {
2766 KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2767 if (!Known.isNonNegative())
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002768 break;
2769 LLVM_FALLTHROUGH;
Craig Topper1a36b7d2017-05-15 06:39:41 +00002770 }
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002771 case ICmpInst::ICMP_EQ:
2772 case ICmpInst::ICMP_UGT:
2773 case ICmpInst::ICMP_UGE:
2774 return getFalse(ITy);
2775 case ICmpInst::ICMP_SLT:
Craig Topper1a36b7d2017-05-15 06:39:41 +00002776 case ICmpInst::ICMP_SLE: {
2777 KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2778 if (!Known.isNonNegative())
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002779 break;
2780 LLVM_FALLTHROUGH;
Craig Topper1a36b7d2017-05-15 06:39:41 +00002781 }
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002782 case ICmpInst::ICMP_NE:
2783 case ICmpInst::ICMP_ULT:
2784 case ICmpInst::ICMP_ULE:
2785 return getTrue(ITy);
2786 }
2787 }
2788
2789 // icmp pred X, (urem Y, X)
2790 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002791 switch (Pred) {
2792 default:
2793 break;
2794 case ICmpInst::ICMP_SGT:
Craig Topper1a36b7d2017-05-15 06:39:41 +00002795 case ICmpInst::ICMP_SGE: {
2796 KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2797 if (!Known.isNonNegative())
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002798 break;
2799 LLVM_FALLTHROUGH;
Craig Topper1a36b7d2017-05-15 06:39:41 +00002800 }
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002801 case ICmpInst::ICMP_NE:
2802 case ICmpInst::ICMP_UGT:
2803 case ICmpInst::ICMP_UGE:
2804 return getTrue(ITy);
2805 case ICmpInst::ICMP_SLT:
Craig Topper1a36b7d2017-05-15 06:39:41 +00002806 case ICmpInst::ICMP_SLE: {
2807 KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2808 if (!Known.isNonNegative())
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002809 break;
2810 LLVM_FALLTHROUGH;
Craig Topper1a36b7d2017-05-15 06:39:41 +00002811 }
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002812 case ICmpInst::ICMP_EQ:
2813 case ICmpInst::ICMP_ULT:
2814 case ICmpInst::ICMP_ULE:
2815 return getFalse(ITy);
2816 }
2817 }
2818
2819 // x >> y <=u x
2820 // x udiv y <=u x.
2821 if (LBO && (match(LBO, m_LShr(m_Specific(RHS), m_Value())) ||
2822 match(LBO, m_UDiv(m_Specific(RHS), m_Value())))) {
2823 // icmp pred (X op Y), X
2824 if (Pred == ICmpInst::ICMP_UGT)
2825 return getFalse(ITy);
2826 if (Pred == ICmpInst::ICMP_ULE)
2827 return getTrue(ITy);
2828 }
2829
2830 // x >=u x >> y
2831 // x >=u x udiv y.
2832 if (RBO && (match(RBO, m_LShr(m_Specific(LHS), m_Value())) ||
2833 match(RBO, m_UDiv(m_Specific(LHS), m_Value())))) {
2834 // icmp pred X, (X op Y)
2835 if (Pred == ICmpInst::ICMP_ULT)
2836 return getFalse(ITy);
2837 if (Pred == ICmpInst::ICMP_UGE)
2838 return getTrue(ITy);
2839 }
2840
2841 // handle:
2842 // CI2 << X == CI
2843 // CI2 << X != CI
2844 //
2845 // where CI2 is a power of 2 and CI isn't
2846 if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
2847 const APInt *CI2Val, *CIVal = &CI->getValue();
2848 if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
2849 CI2Val->isPowerOf2()) {
2850 if (!CIVal->isPowerOf2()) {
2851 // CI2 << X can equal zero in some circumstances,
2852 // this simplification is unsafe if CI is zero.
2853 //
2854 // We know it is safe if:
2855 // - The shift is nsw, we can't shift out the one bit.
2856 // - The shift is nuw, we can't shift out the one bit.
2857 // - CI2 is one
2858 // - CI isn't zero
Florian Hahn19f9e322018-08-17 14:39:04 +00002859 if (Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(LBO)) ||
2860 Q.IIQ.hasNoUnsignedWrap(cast<OverflowingBinaryOperator>(LBO)) ||
Craig Topper73ba1c82017-06-07 07:40:37 +00002861 CI2Val->isOneValue() || !CI->isZero()) {
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002862 if (Pred == ICmpInst::ICMP_EQ)
2863 return ConstantInt::getFalse(RHS->getContext());
2864 if (Pred == ICmpInst::ICMP_NE)
2865 return ConstantInt::getTrue(RHS->getContext());
2866 }
2867 }
Craig Topper73ba1c82017-06-07 07:40:37 +00002868 if (CIVal->isSignMask() && CI2Val->isOneValue()) {
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002869 if (Pred == ICmpInst::ICMP_UGT)
2870 return ConstantInt::getFalse(RHS->getContext());
2871 if (Pred == ICmpInst::ICMP_ULE)
2872 return ConstantInt::getTrue(RHS->getContext());
2873 }
2874 }
2875 }
2876
2877 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2878 LBO->getOperand(1) == RBO->getOperand(1)) {
2879 switch (LBO->getOpcode()) {
2880 default:
2881 break;
2882 case Instruction::UDiv:
2883 case Instruction::LShr:
Florian Hahn19f9e322018-08-17 14:39:04 +00002884 if (ICmpInst::isSigned(Pred) || !Q.IIQ.isExact(LBO) ||
2885 !Q.IIQ.isExact(RBO))
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002886 break;
Sanjay Patela23b1412017-05-15 19:16:49 +00002887 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2888 RBO->getOperand(0), Q, MaxRecurse - 1))
2889 return V;
2890 break;
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002891 case Instruction::SDiv:
Florian Hahn19f9e322018-08-17 14:39:04 +00002892 if (!ICmpInst::isEquality(Pred) || !Q.IIQ.isExact(LBO) ||
2893 !Q.IIQ.isExact(RBO))
Sanjay Patela23b1412017-05-15 19:16:49 +00002894 break;
2895 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2896 RBO->getOperand(0), Q, MaxRecurse - 1))
2897 return V;
2898 break;
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002899 case Instruction::AShr:
Florian Hahn19f9e322018-08-17 14:39:04 +00002900 if (!Q.IIQ.isExact(LBO) || !Q.IIQ.isExact(RBO))
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002901 break;
2902 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2903 RBO->getOperand(0), Q, MaxRecurse - 1))
2904 return V;
2905 break;
2906 case Instruction::Shl: {
Florian Hahn19f9e322018-08-17 14:39:04 +00002907 bool NUW = Q.IIQ.hasNoUnsignedWrap(LBO) && Q.IIQ.hasNoUnsignedWrap(RBO);
2908 bool NSW = Q.IIQ.hasNoSignedWrap(LBO) && Q.IIQ.hasNoSignedWrap(RBO);
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002909 if (!NUW && !NSW)
2910 break;
2911 if (!NSW && ICmpInst::isSigned(Pred))
2912 break;
2913 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2914 RBO->getOperand(0), Q, MaxRecurse - 1))
2915 return V;
2916 break;
2917 }
2918 }
2919 }
2920 return nullptr;
2921}
2922
Sanjay Patel35289c62016-12-10 17:40:47 +00002923/// Simplify integer comparisons where at least one operand of the compare
2924/// matches an integer min/max idiom.
2925static Value *simplifyICmpWithMinMax(CmpInst::Predicate Pred, Value *LHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00002926 Value *RHS, const SimplifyQuery &Q,
Sanjay Patel35289c62016-12-10 17:40:47 +00002927 unsigned MaxRecurse) {
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00002928 Type *ITy = GetCompareTy(LHS); // The return type.
2929 Value *A, *B;
2930 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
2931 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2932
2933 // Signed variants on "max(a,b)>=a -> true".
2934 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2935 if (A != RHS)
2936 std::swap(A, B); // smax(A, B) pred A.
2937 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2938 // We analyze this as smax(A, B) pred A.
2939 P = Pred;
2940 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2941 (A == LHS || B == LHS)) {
2942 if (A != LHS)
2943 std::swap(A, B); // A pred smax(A, B).
2944 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2945 // We analyze this as smax(A, B) swapped-pred A.
2946 P = CmpInst::getSwappedPredicate(Pred);
2947 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2948 (A == RHS || B == RHS)) {
2949 if (A != RHS)
2950 std::swap(A, B); // smin(A, B) pred A.
2951 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2952 // We analyze this as smax(-A, -B) swapped-pred -A.
2953 // Note that we do not need to actually form -A or -B thanks to EqP.
2954 P = CmpInst::getSwappedPredicate(Pred);
2955 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2956 (A == LHS || B == LHS)) {
2957 if (A != LHS)
2958 std::swap(A, B); // A pred smin(A, B).
2959 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2960 // We analyze this as smax(-A, -B) pred -A.
2961 // Note that we do not need to actually form -A or -B thanks to EqP.
2962 P = Pred;
2963 }
2964 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2965 // Cases correspond to "max(A, B) p A".
2966 switch (P) {
2967 default:
2968 break;
2969 case CmpInst::ICMP_EQ:
2970 case CmpInst::ICMP_SLE:
2971 // Equivalent to "A EqP B". This may be the same as the condition tested
2972 // in the max/min; if so, we can just return that.
2973 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2974 return V;
2975 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2976 return V;
2977 // Otherwise, see if "A EqP B" simplifies.
2978 if (MaxRecurse)
2979 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
2980 return V;
2981 break;
2982 case CmpInst::ICMP_NE:
2983 case CmpInst::ICMP_SGT: {
2984 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2985 // Equivalent to "A InvEqP B". This may be the same as the condition
2986 // tested in the max/min; if so, we can just return that.
2987 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2988 return V;
2989 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2990 return V;
2991 // Otherwise, see if "A InvEqP B" simplifies.
2992 if (MaxRecurse)
2993 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
2994 return V;
2995 break;
2996 }
2997 case CmpInst::ICMP_SGE:
2998 // Always true.
2999 return getTrue(ITy);
3000 case CmpInst::ICMP_SLT:
3001 // Always false.
3002 return getFalse(ITy);
3003 }
3004 }
3005
3006 // Unsigned variants on "max(a,b)>=a -> true".
3007 P = CmpInst::BAD_ICMP_PREDICATE;
3008 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
3009 if (A != RHS)
3010 std::swap(A, B); // umax(A, B) pred A.
3011 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
3012 // We analyze this as umax(A, B) pred A.
3013 P = Pred;
3014 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
3015 (A == LHS || B == LHS)) {
3016 if (A != LHS)
3017 std::swap(A, B); // A pred umax(A, B).
3018 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
3019 // We analyze this as umax(A, B) swapped-pred A.
3020 P = CmpInst::getSwappedPredicate(Pred);
3021 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
3022 (A == RHS || B == RHS)) {
3023 if (A != RHS)
3024 std::swap(A, B); // umin(A, B) pred A.
3025 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
3026 // We analyze this as umax(-A, -B) swapped-pred -A.
3027 // Note that we do not need to actually form -A or -B thanks to EqP.
3028 P = CmpInst::getSwappedPredicate(Pred);
3029 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
3030 (A == LHS || B == LHS)) {
3031 if (A != LHS)
3032 std::swap(A, B); // A pred umin(A, B).
3033 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
3034 // We analyze this as umax(-A, -B) pred -A.
3035 // Note that we do not need to actually form -A or -B thanks to EqP.
3036 P = Pred;
3037 }
3038 if (P != CmpInst::BAD_ICMP_PREDICATE) {
3039 // Cases correspond to "max(A, B) p A".
3040 switch (P) {
3041 default:
3042 break;
3043 case CmpInst::ICMP_EQ:
3044 case CmpInst::ICMP_ULE:
3045 // Equivalent to "A EqP B". This may be the same as the condition tested
3046 // in the max/min; if so, we can just return that.
3047 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
3048 return V;
3049 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
3050 return V;
3051 // Otherwise, see if "A EqP B" simplifies.
3052 if (MaxRecurse)
3053 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
3054 return V;
3055 break;
3056 case CmpInst::ICMP_NE:
3057 case CmpInst::ICMP_UGT: {
3058 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
3059 // Equivalent to "A InvEqP B". This may be the same as the condition
3060 // tested in the max/min; if so, we can just return that.
3061 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
3062 return V;
3063 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
3064 return V;
3065 // Otherwise, see if "A InvEqP B" simplifies.
3066 if (MaxRecurse)
3067 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
3068 return V;
3069 break;
3070 }
3071 case CmpInst::ICMP_UGE:
3072 // Always true.
3073 return getTrue(ITy);
3074 case CmpInst::ICMP_ULT:
3075 // Always false.
3076 return getFalse(ITy);
3077 }
3078 }
3079
3080 // Variants on "max(x,y) >= min(x,z)".
3081 Value *C, *D;
3082 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
3083 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
3084 (A == C || A == D || B == C || B == D)) {
3085 // max(x, ?) pred min(x, ?).
3086 if (Pred == CmpInst::ICMP_SGE)
3087 // Always true.
3088 return getTrue(ITy);
3089 if (Pred == CmpInst::ICMP_SLT)
3090 // Always false.
3091 return getFalse(ITy);
3092 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
3093 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
3094 (A == C || A == D || B == C || B == D)) {
3095 // min(x, ?) pred max(x, ?).
3096 if (Pred == CmpInst::ICMP_SLE)
3097 // Always true.
3098 return getTrue(ITy);
3099 if (Pred == CmpInst::ICMP_SGT)
3100 // Always false.
3101 return getFalse(ITy);
3102 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
3103 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
3104 (A == C || A == D || B == C || B == D)) {
3105 // max(x, ?) pred min(x, ?).
3106 if (Pred == CmpInst::ICMP_UGE)
3107 // Always true.
3108 return getTrue(ITy);
3109 if (Pred == CmpInst::ICMP_ULT)
3110 // Always false.
3111 return getFalse(ITy);
3112 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
3113 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
3114 (A == C || A == D || B == C || B == D)) {
3115 // min(x, ?) pred max(x, ?).
3116 if (Pred == CmpInst::ICMP_ULE)
3117 // Always true.
3118 return getTrue(ITy);
3119 if (Pred == CmpInst::ICMP_UGT)
3120 // Always false.
3121 return getFalse(ITy);
3122 }
3123
3124 return nullptr;
3125}
3126
Sanjay Patel472cc782016-01-11 22:14:42 +00003127/// Given operands for an ICmpInst, see if we can fold the result.
3128/// If not, this returns null.
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00003129static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00003130 const SimplifyQuery &Q, unsigned MaxRecurse) {
Chris Lattner084a1b52009-11-09 22:57:59 +00003131 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
Chris Lattnerc1f19072009-11-09 23:28:39 +00003132 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
Duncan Sands7e800d62010-11-14 11:23:23 +00003133
Chris Lattnera71e9d62009-11-10 00:55:12 +00003134 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
Chris Lattnercdfb80d2009-11-09 23:06:58 +00003135 if (Constant *CRHS = dyn_cast<Constant>(RHS))
Rafael Espindola37dc9e12014-02-21 00:06:31 +00003136 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
Chris Lattnera71e9d62009-11-10 00:55:12 +00003137
3138 // If we have a constant, make sure it is on the RHS.
3139 std::swap(LHS, RHS);
3140 Pred = CmpInst::getSwappedPredicate(Pred);
3141 }
Simon Pilgrim8ee477a2019-03-19 14:08:23 +00003142 assert(!isa<UndefValue>(LHS) && "Unexpected icmp undef,%X");
Duncan Sands7e800d62010-11-14 11:23:23 +00003143
Chris Lattner229907c2011-07-18 04:54:35 +00003144 Type *ITy = GetCompareTy(LHS); // The return type.
Duncan Sands7e800d62010-11-14 11:23:23 +00003145
Simon Pilgrim8ee477a2019-03-19 14:08:23 +00003146 // For EQ and NE, we can always pick a value for the undef to make the
3147 // predicate pass or fail, so we can return undef.
3148 // Matches behavior in llvm::ConstantFoldCompareInstruction.
3149 if (isa<UndefValue>(RHS) && ICmpInst::isEquality(Pred))
3150 return UndefValue::get(ITy);
3151
Chris Lattnerccfdceb2009-11-09 23:55:12 +00003152 // icmp X, X -> true/false
Sanjay Patel30be6652018-04-22 17:07:44 +00003153 // icmp X, undef -> true/false because undef could be X.
Duncan Sands772749a2011-01-01 20:08:02 +00003154 if (LHS == RHS || isa<UndefValue>(RHS))
Chris Lattnerccfdceb2009-11-09 23:55:12 +00003155 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
Duncan Sands7e800d62010-11-14 11:23:23 +00003156
Sanjay Pateldc65a272016-12-03 17:30:22 +00003157 if (Value *V = simplifyICmpOfBools(Pred, LHS, RHS, Q))
3158 return V;
Duncan Sands8d25a7c2011-01-13 08:56:29 +00003159
Sanjay Pateldc65a272016-12-03 17:30:22 +00003160 if (Value *V = simplifyICmpWithZero(Pred, LHS, RHS, Q))
3161 return V;
Duncan Sandsd3951082011-01-25 09:38:29 +00003162
Florian Hahn19f9e322018-08-17 14:39:04 +00003163 if (Value *V = simplifyICmpWithConstant(Pred, LHS, RHS, Q.IIQ))
Sanjay Patel67bde282016-08-22 23:12:02 +00003164 return V;
Duncan Sands8d25a7c2011-01-13 08:56:29 +00003165
Chen Li7452d952015-09-26 03:26:47 +00003166 // If both operands have range metadata, use the metadata
3167 // to simplify the comparison.
3168 if (isa<Instruction>(RHS) && isa<Instruction>(LHS)) {
Craig Topper0c198612017-04-10 19:37:10 +00003169 auto RHS_Instr = cast<Instruction>(RHS);
3170 auto LHS_Instr = cast<Instruction>(LHS);
Chen Li7452d952015-09-26 03:26:47 +00003171
Florian Hahn19f9e322018-08-17 14:39:04 +00003172 if (Q.IIQ.getMetadata(RHS_Instr, LLVMContext::MD_range) &&
3173 Q.IIQ.getMetadata(LHS_Instr, LLVMContext::MD_range)) {
Sanjoy Dasa7e13782015-10-24 05:37:35 +00003174 auto RHS_CR = getConstantRangeFromMetadata(
3175 *RHS_Instr->getMetadata(LLVMContext::MD_range));
3176 auto LHS_CR = getConstantRangeFromMetadata(
3177 *LHS_Instr->getMetadata(LLVMContext::MD_range));
Chen Li7452d952015-09-26 03:26:47 +00003178
3179 auto Satisfied_CR = ConstantRange::makeSatisfyingICmpRegion(Pred, RHS_CR);
3180 if (Satisfied_CR.contains(LHS_CR))
3181 return ConstantInt::getTrue(RHS->getContext());
3182
3183 auto InversedSatisfied_CR = ConstantRange::makeSatisfyingICmpRegion(
3184 CmpInst::getInversePredicate(Pred), RHS_CR);
3185 if (InversedSatisfied_CR.contains(LHS_CR))
3186 return ConstantInt::getFalse(RHS->getContext());
3187 }
3188 }
3189
Duncan Sands8fb2c382011-01-20 13:21:55 +00003190 // Compare of cast, for example (zext X) != 0 -> X != 0
3191 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
3192 Instruction *LI = cast<CastInst>(LHS);
3193 Value *SrcOp = LI->getOperand(0);
Chris Lattner229907c2011-07-18 04:54:35 +00003194 Type *SrcTy = SrcOp->getType();
3195 Type *DstTy = LI->getType();
Duncan Sands8fb2c382011-01-20 13:21:55 +00003196
3197 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
3198 // if the integer type is the same size as the pointer type.
Mehdi Aminia28d91d2015-03-10 02:37:25 +00003199 if (MaxRecurse && isa<PtrToIntInst>(LI) &&
3200 Q.DL.getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
Duncan Sands8fb2c382011-01-20 13:21:55 +00003201 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
3202 // Transfer the cast to the constant.
3203 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
3204 ConstantExpr::getIntToPtr(RHSC, SrcTy),
Duncan Sandsb8cee002012-03-13 11:42:19 +00003205 Q, MaxRecurse-1))
Duncan Sands8fb2c382011-01-20 13:21:55 +00003206 return V;
3207 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
3208 if (RI->getOperand(0)->getType() == SrcTy)
3209 // Compare without the cast.
3210 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
Duncan Sandsb8cee002012-03-13 11:42:19 +00003211 Q, MaxRecurse-1))
Duncan Sands8fb2c382011-01-20 13:21:55 +00003212 return V;
3213 }
3214 }
3215
3216 if (isa<ZExtInst>(LHS)) {
3217 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
3218 // same type.
3219 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
3220 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3221 // Compare X and Y. Note that signed predicates become unsigned.
3222 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
Duncan Sandsb8cee002012-03-13 11:42:19 +00003223 SrcOp, RI->getOperand(0), Q,
Duncan Sands8fb2c382011-01-20 13:21:55 +00003224 MaxRecurse-1))
3225 return V;
3226 }
3227 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
3228 // too. If not, then try to deduce the result of the comparison.
3229 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3230 // Compute the constant that would happen if we truncated to SrcTy then
3231 // reextended to DstTy.
3232 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3233 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
3234
3235 // If the re-extended constant didn't change then this is effectively
3236 // also a case of comparing two zero-extended values.
3237 if (RExt == CI && MaxRecurse)
3238 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
Duncan Sandsb8cee002012-03-13 11:42:19 +00003239 SrcOp, Trunc, Q, MaxRecurse-1))
Duncan Sands8fb2c382011-01-20 13:21:55 +00003240 return V;
3241
3242 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
3243 // there. Use this to work out the result of the comparison.
3244 if (RExt != CI) {
3245 switch (Pred) {
Craig Toppera2886c22012-02-07 05:05:23 +00003246 default: llvm_unreachable("Unknown ICmp predicate!");
Duncan Sands8fb2c382011-01-20 13:21:55 +00003247 // LHS <u RHS.
3248 case ICmpInst::ICMP_EQ:
3249 case ICmpInst::ICMP_UGT:
3250 case ICmpInst::ICMP_UGE:
3251 return ConstantInt::getFalse(CI->getContext());
3252
3253 case ICmpInst::ICMP_NE:
3254 case ICmpInst::ICMP_ULT:
3255 case ICmpInst::ICMP_ULE:
3256 return ConstantInt::getTrue(CI->getContext());
3257
3258 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
3259 // is non-negative then LHS <s RHS.
3260 case ICmpInst::ICMP_SGT:
3261 case ICmpInst::ICMP_SGE:
3262 return CI->getValue().isNegative() ?
3263 ConstantInt::getTrue(CI->getContext()) :
3264 ConstantInt::getFalse(CI->getContext());
3265
3266 case ICmpInst::ICMP_SLT:
3267 case ICmpInst::ICMP_SLE:
3268 return CI->getValue().isNegative() ?
3269 ConstantInt::getFalse(CI->getContext()) :
3270 ConstantInt::getTrue(CI->getContext());
3271 }
3272 }
3273 }
3274 }
3275
3276 if (isa<SExtInst>(LHS)) {
3277 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
3278 // same type.
3279 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
3280 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3281 // Compare X and Y. Note that the predicate does not change.
3282 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
Duncan Sandsb8cee002012-03-13 11:42:19 +00003283 Q, MaxRecurse-1))
Duncan Sands8fb2c382011-01-20 13:21:55 +00003284 return V;
3285 }
3286 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
3287 // too. If not, then try to deduce the result of the comparison.
3288 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3289 // Compute the constant that would happen if we truncated to SrcTy then
3290 // reextended to DstTy.
3291 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3292 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
3293
3294 // If the re-extended constant didn't change then this is effectively
3295 // also a case of comparing two sign-extended values.
3296 if (RExt == CI && MaxRecurse)
Duncan Sandsb8cee002012-03-13 11:42:19 +00003297 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
Duncan Sands8fb2c382011-01-20 13:21:55 +00003298 return V;
3299
3300 // Otherwise the upper bits of LHS are all equal, while RHS has varying
3301 // bits there. Use this to work out the result of the comparison.
3302 if (RExt != CI) {
3303 switch (Pred) {
Craig Toppera2886c22012-02-07 05:05:23 +00003304 default: llvm_unreachable("Unknown ICmp predicate!");
Duncan Sands8fb2c382011-01-20 13:21:55 +00003305 case ICmpInst::ICMP_EQ:
3306 return ConstantInt::getFalse(CI->getContext());
3307 case ICmpInst::ICMP_NE:
3308 return ConstantInt::getTrue(CI->getContext());
3309
3310 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
3311 // LHS >s RHS.
3312 case ICmpInst::ICMP_SGT:
3313 case ICmpInst::ICMP_SGE:
3314 return CI->getValue().isNegative() ?
3315 ConstantInt::getTrue(CI->getContext()) :
3316 ConstantInt::getFalse(CI->getContext());
3317 case ICmpInst::ICMP_SLT:
3318 case ICmpInst::ICMP_SLE:
3319 return CI->getValue().isNegative() ?
3320 ConstantInt::getFalse(CI->getContext()) :
3321 ConstantInt::getTrue(CI->getContext());
3322
3323 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
3324 // LHS >u RHS.
3325 case ICmpInst::ICMP_UGT:
3326 case ICmpInst::ICMP_UGE:
Sylvestre Ledru91ce36c2012-09-27 10:14:43 +00003327 // Comparison is true iff the LHS <s 0.
Duncan Sands8fb2c382011-01-20 13:21:55 +00003328 if (MaxRecurse)
3329 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
3330 Constant::getNullValue(SrcTy),
Duncan Sandsb8cee002012-03-13 11:42:19 +00003331 Q, MaxRecurse-1))
Duncan Sands8fb2c382011-01-20 13:21:55 +00003332 return V;
3333 break;
3334 case ICmpInst::ICMP_ULT:
3335 case ICmpInst::ICMP_ULE:
Sylvestre Ledru91ce36c2012-09-27 10:14:43 +00003336 // Comparison is true iff the LHS >=s 0.
Duncan Sands8fb2c382011-01-20 13:21:55 +00003337 if (MaxRecurse)
3338 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
3339 Constant::getNullValue(SrcTy),
Duncan Sandsb8cee002012-03-13 11:42:19 +00003340 Q, MaxRecurse-1))
Duncan Sands8fb2c382011-01-20 13:21:55 +00003341 return V;
3342 break;
3343 }
3344 }
3345 }
3346 }
3347 }
3348
James Molloy1d88d6f2015-10-22 13:18:42 +00003349 // icmp eq|ne X, Y -> false|true if X != Y
Craig Topperc2790ec2017-06-06 07:13:04 +00003350 if (ICmpInst::isEquality(Pred) &&
Florian Hahn19f9e322018-08-17 14:39:04 +00003351 isKnownNonEqual(LHS, RHS, Q.DL, Q.AC, Q.CxtI, Q.DT, Q.IIQ.UseInstrInfo)) {
Craig Topper2dfb4802017-06-06 07:13:13 +00003352 return Pred == ICmpInst::ICMP_NE ? getTrue(ITy) : getFalse(ITy);
James Molloy1d88d6f2015-10-22 13:18:42 +00003353 }
Junmo Park53470fc2016-04-05 21:14:31 +00003354
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00003355 if (Value *V = simplifyICmpWithBinOp(Pred, LHS, RHS, Q, MaxRecurse))
3356 return V;
Duncan Sandsd114ab32011-02-13 17:15:40 +00003357
Sanjay Patel35289c62016-12-10 17:40:47 +00003358 if (Value *V = simplifyICmpWithMinMax(Pred, LHS, RHS, Q, MaxRecurse))
Sanjay Patel9d5b5e32016-12-03 18:03:53 +00003359 return V;
Duncan Sandsa2287852011-05-04 16:05:05 +00003360
Chandler Carruth8059c842012-03-25 21:28:14 +00003361 // Simplify comparisons of related pointers using a powerful, recursive
3362 // GEP-walk when we have target data available..
Dan Gohman18c77a12013-01-31 02:50:36 +00003363 if (LHS->getType()->isPointerTy())
Florian Hahn19f9e322018-08-17 14:39:04 +00003364 if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI,
3365 Q.IIQ, LHS, RHS))
Chandler Carruth8059c842012-03-25 21:28:14 +00003366 return C;
David Majnemerdc8767a2016-08-07 07:58:10 +00003367 if (auto *CLHS = dyn_cast<PtrToIntOperator>(LHS))
3368 if (auto *CRHS = dyn_cast<PtrToIntOperator>(RHS))
3369 if (Q.DL.getTypeSizeInBits(CLHS->getPointerOperandType()) ==
3370 Q.DL.getTypeSizeInBits(CLHS->getType()) &&
3371 Q.DL.getTypeSizeInBits(CRHS->getPointerOperandType()) ==
3372 Q.DL.getTypeSizeInBits(CRHS->getType()))
Nuno Lopes404f1062017-09-09 18:23:11 +00003373 if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI,
Florian Hahn19f9e322018-08-17 14:39:04 +00003374 Q.IIQ, CLHS->getPointerOperand(),
David Majnemerdc8767a2016-08-07 07:58:10 +00003375 CRHS->getPointerOperand()))
3376 return C;
Chandler Carruth8059c842012-03-25 21:28:14 +00003377
Nick Lewycky3db143e2012-02-26 02:09:49 +00003378 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
3379 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
3380 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
3381 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
3382 (ICmpInst::isEquality(Pred) ||
3383 (GLHS->isInBounds() && GRHS->isInBounds() &&
3384 Pred == ICmpInst::getSignedPredicate(Pred)))) {
3385 // The bases are equal and the indices are constant. Build a constant
3386 // expression GEP with the same indices and a null base pointer to see
3387 // what constant folding can make out of it.
3388 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
3389 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
David Blaikie4a2e73b2015-04-02 18:55:32 +00003390 Constant *NewLHS = ConstantExpr::getGetElementPtr(
3391 GLHS->getSourceElementType(), Null, IndicesLHS);
Nick Lewycky3db143e2012-02-26 02:09:49 +00003392
3393 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
David Blaikie4a2e73b2015-04-02 18:55:32 +00003394 Constant *NewRHS = ConstantExpr::getGetElementPtr(
3395 GLHS->getSourceElementType(), Null, IndicesRHS);
Nick Lewycky3db143e2012-02-26 02:09:49 +00003396 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
3397 }
3398 }
3399 }
3400
Duncan Sandsf532d312010-11-07 16:12:23 +00003401 // If the comparison is with the result of a select instruction, check whether
3402 // comparing with either branch of the select always yields the same value.
Duncan Sandsf64e6902010-12-21 09:09:15 +00003403 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
Duncan Sandsb8cee002012-03-13 11:42:19 +00003404 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00003405 return V;
3406
3407 // If the comparison is with the result of a phi instruction, check whether
3408 // doing the compare with each incoming phi value yields a common result.
Duncan Sandsf64e6902010-12-21 09:09:15 +00003409 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
Duncan Sandsb8cee002012-03-13 11:42:19 +00003410 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
Duncan Sandsfc5ad3f02010-11-09 17:25:51 +00003411 return V;
Duncan Sandsf532d312010-11-07 16:12:23 +00003412
Craig Topper9f008862014-04-15 04:59:12 +00003413 return nullptr;
Chris Lattner084a1b52009-11-09 22:57:59 +00003414}
3415
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00003416Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00003417 const SimplifyQuery &Q) {
3418 return ::SimplifyICmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
3419}
3420
Sanjay Patel472cc782016-01-11 22:14:42 +00003421/// Given operands for an FCmpInst, see if we can fold the result.
3422/// If not, this returns null.
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00003423static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00003424 FastMathFlags FMF, const SimplifyQuery &Q,
Benjamin Kramerf4ebfa32015-07-10 14:02:02 +00003425 unsigned MaxRecurse) {
Chris Lattnerc1f19072009-11-09 23:28:39 +00003426 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3427 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
3428
Chris Lattnera71e9d62009-11-10 00:55:12 +00003429 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
Chris Lattnerc1f19072009-11-09 23:28:39 +00003430 if (Constant *CRHS = dyn_cast<Constant>(RHS))
Rafael Espindola37dc9e12014-02-21 00:06:31 +00003431 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
Duncan Sands7e800d62010-11-14 11:23:23 +00003432
Chris Lattnera71e9d62009-11-10 00:55:12 +00003433 // If we have a constant, make sure it is on the RHS.
3434 std::swap(LHS, RHS);
3435 Pred = CmpInst::getSwappedPredicate(Pred);
3436 }
Duncan Sands7e800d62010-11-14 11:23:23 +00003437
Chris Lattnerccfdceb2009-11-09 23:55:12 +00003438 // Fold trivial predicates.
Andrea Di Biagiobff3fd62016-09-02 15:55:25 +00003439 Type *RetTy = GetCompareTy(LHS);
Chris Lattnerccfdceb2009-11-09 23:55:12 +00003440 if (Pred == FCmpInst::FCMP_FALSE)
Andrea Di Biagiobff3fd62016-09-02 15:55:25 +00003441 return getFalse(RetTy);
Chris Lattnerccfdceb2009-11-09 23:55:12 +00003442 if (Pred == FCmpInst::FCMP_TRUE)
Andrea Di Biagiobff3fd62016-09-02 15:55:25 +00003443 return getTrue(RetTy);
Chris Lattnerccfdceb2009-11-09 23:55:12 +00003444
Sanjay Patelf3ae9cc2018-08-21 14:45:13 +00003445 // Fold (un)ordered comparison if we can determine there are no NaNs.
3446 if (Pred == FCmpInst::FCMP_UNO || Pred == FCmpInst::FCMP_ORD)
3447 if (FMF.noNaNs() ||
3448 (isKnownNeverNaN(LHS, Q.TLI) && isKnownNeverNaN(RHS, Q.TLI)))
3449 return ConstantInt::get(RetTy, Pred == FCmpInst::FCMP_ORD);
Benjamin Kramerf4ebfa32015-07-10 14:02:02 +00003450
Sanjay Patel46b083e2018-03-02 18:36:08 +00003451 // NaN is unordered; NaN is not ordered.
3452 assert((FCmpInst::isOrdered(Pred) || FCmpInst::isUnordered(Pred)) &&
3453 "Comparison must be either ordered or unordered");
3454 if (match(RHS, m_NaN()))
3455 return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred));
3456
Mehdi Aminieb242a52015-03-09 03:20:25 +00003457 // fcmp pred x, undef and fcmp pred undef, x
3458 // fold to true if unordered, false if ordered
3459 if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS)) {
3460 // Choosing NaN for the undef will always make unordered comparison succeed
3461 // and ordered comparison fail.
Andrea Di Biagiobff3fd62016-09-02 15:55:25 +00003462 return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred));
Mehdi Aminieb242a52015-03-09 03:20:25 +00003463 }
Chris Lattnerccfdceb2009-11-09 23:55:12 +00003464
3465 // fcmp x,x -> true/false. Not all compares are foldable.
Duncan Sands772749a2011-01-01 20:08:02 +00003466 if (LHS == RHS) {
Chris Lattnerccfdceb2009-11-09 23:55:12 +00003467 if (CmpInst::isTrueWhenEqual(Pred))
Andrea Di Biagiobff3fd62016-09-02 15:55:25 +00003468 return getTrue(RetTy);
Chris Lattnerccfdceb2009-11-09 23:55:12 +00003469 if (CmpInst::isFalseWhenEqual(Pred))
Andrea Di Biagiobff3fd62016-09-02 15:55:25 +00003470 return getFalse(RetTy);
Chris Lattnerccfdceb2009-11-09 23:55:12 +00003471 }
Duncan Sands7e800d62010-11-14 11:23:23 +00003472
Sanjay Patel4ca99682017-11-27 16:37:09 +00003473 // Handle fcmp with constant RHS.
Sanjay Patel68171e32019-02-20 14:34:00 +00003474 // TODO: Use match with a specific FP value, so these work with vectors with
3475 // undef lanes.
Sanjay Patel4ca99682017-11-27 16:37:09 +00003476 const APFloat *C;
3477 if (match(RHS, m_APFloat(C))) {
Mehdi Amini383d7ae2015-02-13 07:38:04 +00003478 // Check whether the constant is an infinity.
Sanjay Patel4ca99682017-11-27 16:37:09 +00003479 if (C->isInfinity()) {
3480 if (C->isNegative()) {
Elena Demikhovsky45f04482015-01-28 08:03:58 +00003481 switch (Pred) {
Elena Demikhovsky45f04482015-01-28 08:03:58 +00003482 case FCmpInst::FCMP_OLT:
Mehdi Amini383d7ae2015-02-13 07:38:04 +00003483 // No value is ordered and less than negative infinity.
Andrea Di Biagiobff3fd62016-09-02 15:55:25 +00003484 return getFalse(RetTy);
Mehdi Amini383d7ae2015-02-13 07:38:04 +00003485 case FCmpInst::FCMP_UGE:
3486 // All values are unordered with or at least negative infinity.
Andrea Di Biagiobff3fd62016-09-02 15:55:25 +00003487 return getTrue(RetTy);
Elena Demikhovsky45f04482015-01-28 08:03:58 +00003488 default:
3489 break;
3490 }
Mehdi Amini383d7ae2015-02-13 07:38:04 +00003491 } else {
3492 switch (Pred) {
3493 case FCmpInst::FCMP_OGT:
3494 // No value is ordered and greater than infinity.
Andrea Di Biagiobff3fd62016-09-02 15:55:25 +00003495 return getFalse(RetTy);
Mehdi Amini383d7ae2015-02-13 07:38:04 +00003496 case FCmpInst::FCMP_ULE:
3497 // All values are unordered with and at most infinity.
Andrea Di Biagiobff3fd62016-09-02 15:55:25 +00003498 return getTrue(RetTy);
Mehdi Amini383d7ae2015-02-13 07:38:04 +00003499 default:
3500 break;
3501 }
3502 }
Sanjay Patel49f97392019-02-20 00:20:38 +00003503 }
Sanjay Patel68171e32019-02-20 14:34:00 +00003504 if (C->isNegative() && !C->isNegZero()) {
Florian Hahn30932a32017-12-01 12:34:16 +00003505 assert(!C->isNaN() && "Unexpected NaN constant!");
3506 // TODO: We can catch more cases by using a range check rather than
3507 // relying on CannotBeOrderedLessThanZero.
3508 switch (Pred) {
3509 case FCmpInst::FCMP_UGE:
3510 case FCmpInst::FCMP_UGT:
3511 case FCmpInst::FCMP_UNE:
3512 // (X >= 0) implies (X > C) when (C < 0)
3513 if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3514 return getTrue(RetTy);
3515 break;
3516 case FCmpInst::FCMP_OEQ:
3517 case FCmpInst::FCMP_OLE:
3518 case FCmpInst::FCMP_OLT:
3519 // (X >= 0) implies !(X < C) when (C < 0)
3520 if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3521 return getFalse(RetTy);
3522 break;
3523 default:
3524 break;
3525 }
Chris Lattnerccfdceb2009-11-09 23:55:12 +00003526 }
Sanjay Patel152f81f2019-05-16 14:03:10 +00003527
Sanjay Patel63fa6902019-05-20 17:52:18 +00003528 // Check comparison of [minnum/maxnum with constant] with other constant.
Sanjay Patel9ef99b42019-05-19 14:26:39 +00003529 const APFloat *C2;
3530 if ((match(LHS, m_Intrinsic<Intrinsic::minnum>(m_Value(), m_APFloat(C2))) &&
3531 C2->compare(*C) == APFloat::cmpLessThan) ||
3532 (match(LHS, m_Intrinsic<Intrinsic::maxnum>(m_Value(), m_APFloat(C2))) &&
3533 C2->compare(*C) == APFloat::cmpGreaterThan)) {
3534 bool IsMaxNum =
3535 cast<IntrinsicInst>(LHS)->getIntrinsicID() == Intrinsic::maxnum;
3536 // The ordered relationship and minnum/maxnum guarantee that we do not
3537 // have NaN constants, so ordered/unordered preds are handled the same.
Sanjay Patel152f81f2019-05-16 14:03:10 +00003538 switch (Pred) {
3539 case FCmpInst::FCMP_OEQ: case FCmpInst::FCMP_UEQ:
Sanjay Patel9ef99b42019-05-19 14:26:39 +00003540 // minnum(X, LesserC) == C --> false
3541 // maxnum(X, GreaterC) == C --> false
Sanjay Patel152f81f2019-05-16 14:03:10 +00003542 return getFalse(RetTy);
3543 case FCmpInst::FCMP_ONE: case FCmpInst::FCMP_UNE:
Sanjay Patel9ef99b42019-05-19 14:26:39 +00003544 // minnum(X, LesserC) != C --> true
3545 // maxnum(X, GreaterC) != C --> true
3546 return getTrue(RetTy);
3547 case FCmpInst::FCMP_OGE: case FCmpInst::FCMP_UGE:
3548 case FCmpInst::FCMP_OGT: case FCmpInst::FCMP_UGT:
3549 // minnum(X, LesserC) >= C --> false
3550 // minnum(X, LesserC) > C --> false
3551 // maxnum(X, GreaterC) >= C --> true
3552 // maxnum(X, GreaterC) > C --> true
3553 return ConstantInt::get(RetTy, IsMaxNum);
Sanjay Patel152f81f2019-05-16 14:03:10 +00003554 case FCmpInst::FCMP_OLE: case FCmpInst::FCMP_ULE:
3555 case FCmpInst::FCMP_OLT: case FCmpInst::FCMP_ULT:
Sanjay Patel9ef99b42019-05-19 14:26:39 +00003556 // minnum(X, LesserC) <= C --> true
3557 // minnum(X, LesserC) < C --> true
3558 // maxnum(X, GreaterC) <= C --> false
3559 // maxnum(X, GreaterC) < C --> false
3560 return ConstantInt::get(RetTy, !IsMaxNum);
Sanjay Patel152f81f2019-05-16 14:03:10 +00003561 default:
3562 // TRUE/FALSE/ORD/UNO should be handled before this.
3563 llvm_unreachable("Unexpected fcmp predicate");
3564 }
3565 }
Chris Lattnerccfdceb2009-11-09 23:55:12 +00003566 }
Sanjay Patel152f81f2019-05-16 14:03:10 +00003567
Sanjay Patel68171e32019-02-20 14:34:00 +00003568 if (match(RHS, m_AnyZeroFP())) {
3569 switch (Pred) {
3570 case FCmpInst::FCMP_OGE:
Sanjay Patel866db102019-06-09 13:58:46 +00003571 case FCmpInst::FCMP_ULT:
3572 // Positive or zero X >= 0.0 --> true
3573 // Positive or zero X < 0.0 --> false
Sanjay Patel4329c152019-06-08 15:12:33 +00003574 if ((FMF.noNaNs() || isKnownNeverNaN(LHS, Q.TLI)) &&
3575 CannotBeOrderedLessThanZero(LHS, Q.TLI))
Sanjay Patel866db102019-06-09 13:58:46 +00003576 return Pred == FCmpInst::FCMP_OGE ? getTrue(RetTy) : getFalse(RetTy);
Sanjay Patel68171e32019-02-20 14:34:00 +00003577 break;
3578 case FCmpInst::FCMP_UGE:
Sanjay Patel68171e32019-02-20 14:34:00 +00003579 case FCmpInst::FCMP_OLT:
Sanjay Patel866db102019-06-09 13:58:46 +00003580 // Positive or zero or nan X >= 0.0 --> true
3581 // Positive or zero or nan X < 0.0 --> false
Sanjay Patel68171e32019-02-20 14:34:00 +00003582 if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
Sanjay Patel866db102019-06-09 13:58:46 +00003583 return Pred == FCmpInst::FCMP_UGE ? getTrue(RetTy) : getFalse(RetTy);
Sanjay Patel68171e32019-02-20 14:34:00 +00003584 break;
3585 default:
3586 break;
3587 }
3588 }
Duncan Sands7e800d62010-11-14 11:23:23 +00003589
Duncan Sandsa620bd12010-11-07 16:46:25 +00003590 // If the comparison is with the result of a select instruction, check whether
3591 // comparing with either branch of the select always yields the same value.
Duncan Sandsf64e6902010-12-21 09:09:15 +00003592 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
Duncan Sandsb8cee002012-03-13 11:42:19 +00003593 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00003594 return V;
3595
3596 // If the comparison is with the result of a phi instruction, check whether
3597 // doing the compare with each incoming phi value yields a common result.
Duncan Sandsf64e6902010-12-21 09:09:15 +00003598 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
Duncan Sandsb8cee002012-03-13 11:42:19 +00003599 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
Duncan Sandsfc5ad3f02010-11-09 17:25:51 +00003600 return V;
Duncan Sandsa620bd12010-11-07 16:46:25 +00003601
Craig Topper9f008862014-04-15 04:59:12 +00003602 return nullptr;
Chris Lattnerc1f19072009-11-09 23:28:39 +00003603}
3604
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00003605Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00003606 FastMathFlags FMF, const SimplifyQuery &Q) {
3607 return ::SimplifyFCmpInst(Predicate, LHS, RHS, FMF, Q, RecursionLimit);
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00003608}
3609
Sanjay Patel472cc782016-01-11 22:14:42 +00003610/// See if V simplifies when its operand Op is replaced with RepOp.
David Majnemer3f0fb982015-06-06 22:40:21 +00003611static const Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00003612 const SimplifyQuery &Q,
David Majnemer3f0fb982015-06-06 22:40:21 +00003613 unsigned MaxRecurse) {
3614 // Trivial replacement.
3615 if (V == Op)
3616 return RepOp;
3617
Tim Northover997f5f12017-05-22 21:28:08 +00003618 // We cannot replace a constant, and shouldn't even try.
3619 if (isa<Constant>(Op))
3620 return nullptr;
3621
David Majnemer3f0fb982015-06-06 22:40:21 +00003622 auto *I = dyn_cast<Instruction>(V);
3623 if (!I)
3624 return nullptr;
3625
3626 // If this is a binary operator, try to simplify it with the replaced op.
3627 if (auto *B = dyn_cast<BinaryOperator>(I)) {
3628 // Consider:
3629 // %cmp = icmp eq i32 %x, 2147483647
3630 // %add = add nsw i32 %x, 1
3631 // %sel = select i1 %cmp, i32 -2147483648, i32 %add
3632 //
3633 // We can't replace %sel with %add unless we strip away the flags.
Sanjay Patel9ce5f412019-08-02 17:39:32 +00003634 // TODO: This is an unusual limitation because better analysis results in
3635 // worse simplification. InstCombine can do this fold more generally
3636 // by dropping the flags. Remove this fold to save compile-time?
David Majnemer3f0fb982015-06-06 22:40:21 +00003637 if (isa<OverflowingBinaryOperator>(B))
Florian Hahn19f9e322018-08-17 14:39:04 +00003638 if (Q.IIQ.hasNoSignedWrap(B) || Q.IIQ.hasNoUnsignedWrap(B))
David Majnemer3f0fb982015-06-06 22:40:21 +00003639 return nullptr;
Florian Hahn19f9e322018-08-17 14:39:04 +00003640 if (isa<PossiblyExactOperator>(B) && Q.IIQ.isExact(B))
3641 return nullptr;
David Majnemer3f0fb982015-06-06 22:40:21 +00003642
3643 if (MaxRecurse) {
3644 if (B->getOperand(0) == Op)
3645 return SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), Q,
3646 MaxRecurse - 1);
3647 if (B->getOperand(1) == Op)
3648 return SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, Q,
3649 MaxRecurse - 1);
3650 }
3651 }
3652
3653 // Same for CmpInsts.
3654 if (CmpInst *C = dyn_cast<CmpInst>(I)) {
3655 if (MaxRecurse) {
3656 if (C->getOperand(0) == Op)
3657 return SimplifyCmpInst(C->getPredicate(), RepOp, C->getOperand(1), Q,
3658 MaxRecurse - 1);
3659 if (C->getOperand(1) == Op)
3660 return SimplifyCmpInst(C->getPredicate(), C->getOperand(0), RepOp, Q,
3661 MaxRecurse - 1);
3662 }
3663 }
3664
George Burgess IV8e807bf2018-04-24 00:25:01 +00003665 // Same for GEPs.
3666 if (auto *GEP = dyn_cast<GetElementPtrInst>(I)) {
3667 if (MaxRecurse) {
3668 SmallVector<Value *, 8> NewOps(GEP->getNumOperands());
3669 transform(GEP->operands(), NewOps.begin(),
3670 [&](Value *V) { return V == Op ? RepOp : V; });
3671 return SimplifyGEPInst(GEP->getSourceElementType(), NewOps, Q,
3672 MaxRecurse - 1);
3673 }
3674 }
3675
David Majnemer3f0fb982015-06-06 22:40:21 +00003676 // TODO: We could hand off more cases to instsimplify here.
3677
3678 // If all operands are constant after substituting Op for RepOp then we can
3679 // constant fold the instruction.
3680 if (Constant *CRepOp = dyn_cast<Constant>(RepOp)) {
3681 // Build a list of all constant operands.
3682 SmallVector<Constant *, 8> ConstOps;
3683 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
3684 if (I->getOperand(i) == Op)
3685 ConstOps.push_back(CRepOp);
3686 else if (Constant *COp = dyn_cast<Constant>(I->getOperand(i)))
3687 ConstOps.push_back(COp);
3688 else
3689 break;
3690 }
3691
3692 // All operands were constants, fold it.
3693 if (ConstOps.size() == I->getNumOperands()) {
3694 if (CmpInst *C = dyn_cast<CmpInst>(I))
3695 return ConstantFoldCompareInstOperands(C->getPredicate(), ConstOps[0],
3696 ConstOps[1], Q.DL, Q.TLI);
3697
3698 if (LoadInst *LI = dyn_cast<LoadInst>(I))
3699 if (!LI->isVolatile())
Eduard Burtescu14239212016-01-22 01:17:26 +00003700 return ConstantFoldLoadFromConstPtr(ConstOps[0], LI->getType(), Q.DL);
David Majnemer3f0fb982015-06-06 22:40:21 +00003701
Manuel Jacobe9024592016-01-21 06:33:22 +00003702 return ConstantFoldInstOperands(I, ConstOps, Q.DL, Q.TLI);
David Majnemer3f0fb982015-06-06 22:40:21 +00003703 }
3704 }
3705
3706 return nullptr;
3707}
3708
Sanjay Patel5f5eb582016-07-18 20:56:53 +00003709/// Try to simplify a select instruction when its condition operand is an
3710/// integer comparison where one operand of the compare is a constant.
3711static Value *simplifySelectBitTest(Value *TrueVal, Value *FalseVal, Value *X,
3712 const APInt *Y, bool TrueWhenUnset) {
3713 const APInt *C;
3714
3715 // (X & Y) == 0 ? X & ~Y : X --> X
3716 // (X & Y) != 0 ? X & ~Y : X --> X & ~Y
3717 if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) &&
3718 *Y == ~*C)
3719 return TrueWhenUnset ? FalseVal : TrueVal;
3720
3721 // (X & Y) == 0 ? X : X & ~Y --> X & ~Y
3722 // (X & Y) != 0 ? X : X & ~Y --> X
3723 if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) &&
3724 *Y == ~*C)
3725 return TrueWhenUnset ? FalseVal : TrueVal;
3726
3727 if (Y->isPowerOf2()) {
3728 // (X & Y) == 0 ? X | Y : X --> X | Y
3729 // (X & Y) != 0 ? X | Y : X --> X
3730 if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) &&
3731 *Y == *C)
3732 return TrueWhenUnset ? TrueVal : FalseVal;
3733
3734 // (X & Y) == 0 ? X : X | Y --> X
3735 // (X & Y) != 0 ? X : X | Y --> X | Y
3736 if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) &&
3737 *Y == *C)
3738 return TrueWhenUnset ? TrueVal : FalseVal;
3739 }
Matt Arsenault82606662017-01-11 00:57:54 +00003740
Sanjay Patel5f5eb582016-07-18 20:56:53 +00003741 return nullptr;
3742}
3743
Sanjay Patela3bfb4e2016-07-21 21:26:45 +00003744/// An alternative way to test if a bit is set or not uses sgt/slt instead of
3745/// eq/ne.
Craig Topper0aa3a192017-08-14 21:39:51 +00003746static Value *simplifySelectWithFakeICmpEq(Value *CmpLHS, Value *CmpRHS,
3747 ICmpInst::Predicate Pred,
3748 Value *TrueVal, Value *FalseVal) {
3749 Value *X;
3750 APInt Mask;
3751 if (!decomposeBitTestICmp(CmpLHS, CmpRHS, Pred, X, Mask))
3752 return nullptr;
3753
Craig Topper0aa3a192017-08-14 21:39:51 +00003754 return simplifySelectBitTest(TrueVal, FalseVal, X, &Mask,
3755 Pred == ICmpInst::ICMP_EQ);
Sanjay Patela3bfb4e2016-07-21 21:26:45 +00003756}
3757
Sanjay Patel5f5eb582016-07-18 20:56:53 +00003758/// Try to simplify a select instruction when its condition operand is an
3759/// integer comparison.
3760static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00003761 Value *FalseVal, const SimplifyQuery &Q,
Sanjay Patel5f5eb582016-07-18 20:56:53 +00003762 unsigned MaxRecurse) {
3763 ICmpInst::Predicate Pred;
3764 Value *CmpLHS, *CmpRHS;
3765 if (!match(CondVal, m_ICmp(Pred, m_Value(CmpLHS), m_Value(CmpRHS))))
3766 return nullptr;
3767
Sanjay Patel5f5eb582016-07-18 20:56:53 +00003768 if (ICmpInst::isEquality(Pred) && match(CmpRHS, m_Zero())) {
3769 Value *X;
3770 const APInt *Y;
3771 if (match(CmpLHS, m_And(m_Value(X), m_APInt(Y))))
3772 if (Value *V = simplifySelectBitTest(TrueVal, FalseVal, X, Y,
3773 Pred == ICmpInst::ICMP_EQ))
3774 return V;
Sanjay Patele98ec772018-11-15 14:53:37 +00003775
Sanjay Patel9dada832019-02-26 18:26:56 +00003776 // Test for a bogus zero-shift-guard-op around funnel-shift or rotate.
Sanjay Patele98ec772018-11-15 14:53:37 +00003777 Value *ShAmt;
3778 auto isFsh = m_CombineOr(m_Intrinsic<Intrinsic::fshl>(m_Value(X), m_Value(),
3779 m_Value(ShAmt)),
3780 m_Intrinsic<Intrinsic::fshr>(m_Value(), m_Value(X),
3781 m_Value(ShAmt)));
Sanjay Patele98ec772018-11-15 14:53:37 +00003782 // (ShAmt == 0) ? fshl(X, *, ShAmt) : X --> X
3783 // (ShAmt == 0) ? fshr(*, X, ShAmt) : X --> X
Sanjay Patel9dada832019-02-26 18:26:56 +00003784 if (match(TrueVal, isFsh) && FalseVal == X && CmpLHS == ShAmt &&
3785 Pred == ICmpInst::ICMP_EQ)
3786 return X;
Sanjay Patele98ec772018-11-15 14:53:37 +00003787 // (ShAmt != 0) ? X : fshl(X, *, ShAmt) --> X
3788 // (ShAmt != 0) ? X : fshr(*, X, ShAmt) --> X
Sanjay Patel9dada832019-02-26 18:26:56 +00003789 if (match(FalseVal, isFsh) && TrueVal == X && CmpLHS == ShAmt &&
3790 Pred == ICmpInst::ICMP_NE)
3791 return X;
3792
3793 // Test for a zero-shift-guard-op around rotates. These are used to
3794 // avoid UB from oversized shifts in raw IR rotate patterns, but the
3795 // intrinsics do not have that problem.
3796 // We do not allow this transform for the general funnel shift case because
3797 // that would not preserve the poison safety of the original code.
3798 auto isRotate = m_CombineOr(m_Intrinsic<Intrinsic::fshl>(m_Value(X),
3799 m_Deferred(X),
3800 m_Value(ShAmt)),
3801 m_Intrinsic<Intrinsic::fshr>(m_Value(X),
3802 m_Deferred(X),
3803 m_Value(ShAmt)));
3804 // (ShAmt != 0) ? fshl(X, X, ShAmt) : X --> fshl(X, X, ShAmt)
3805 // (ShAmt != 0) ? fshr(X, X, ShAmt) : X --> fshr(X, X, ShAmt)
3806 if (match(TrueVal, isRotate) && FalseVal == X && CmpLHS == ShAmt &&
3807 Pred == ICmpInst::ICMP_NE)
3808 return TrueVal;
3809 // (ShAmt == 0) ? X : fshl(X, X, ShAmt) --> fshl(X, X, ShAmt)
3810 // (ShAmt == 0) ? X : fshr(X, X, ShAmt) --> fshr(X, X, ShAmt)
3811 if (match(FalseVal, isRotate) && TrueVal == X && CmpLHS == ShAmt &&
3812 Pred == ICmpInst::ICMP_EQ)
3813 return FalseVal;
Sanjay Patel5f5eb582016-07-18 20:56:53 +00003814 }
3815
Craig Topper0aa3a192017-08-14 21:39:51 +00003816 // Check for other compares that behave like bit test.
3817 if (Value *V = simplifySelectWithFakeICmpEq(CmpLHS, CmpRHS, Pred,
3818 TrueVal, FalseVal))
3819 return V;
3820
Sanjay Patel5f5eb582016-07-18 20:56:53 +00003821 // If we have an equality comparison, then we know the value in one of the
3822 // arms of the select. See if substituting this value into the arm and
3823 // simplifying the result yields the same value as the other arm.
3824 if (Pred == ICmpInst::ICMP_EQ) {
3825 if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3826 TrueVal ||
3827 SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3828 TrueVal)
3829 return FalseVal;
3830 if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3831 FalseVal ||
3832 SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3833 FalseVal)
3834 return FalseVal;
3835 } else if (Pred == ICmpInst::ICMP_NE) {
3836 if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3837 FalseVal ||
3838 SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3839 FalseVal)
3840 return TrueVal;
3841 if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3842 TrueVal ||
3843 SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3844 TrueVal)
3845 return TrueVal;
3846 }
3847
3848 return nullptr;
3849}
3850
Sanjay Patel14401072018-11-05 21:51:39 +00003851/// Try to simplify a select instruction when its condition operand is a
3852/// floating-point comparison.
3853static Value *simplifySelectWithFCmp(Value *Cond, Value *T, Value *F) {
3854 FCmpInst::Predicate Pred;
3855 if (!match(Cond, m_FCmp(Pred, m_Specific(T), m_Specific(F))) &&
3856 !match(Cond, m_FCmp(Pred, m_Specific(F), m_Specific(T))))
3857 return nullptr;
3858
3859 // TODO: The transform may not be valid with -0.0. An incomplete way of
3860 // testing for that possibility is to check if at least one operand is a
3861 // non-zero constant.
3862 const APFloat *C;
3863 if ((match(T, m_APFloat(C)) && C->isNonZero()) ||
3864 (match(F, m_APFloat(C)) && C->isNonZero())) {
3865 // (T == F) ? T : F --> F
3866 // (F == T) ? T : F --> F
3867 if (Pred == FCmpInst::FCMP_OEQ)
3868 return F;
3869
3870 // (T != F) ? T : F --> T
3871 // (F != T) ? T : F --> T
3872 if (Pred == FCmpInst::FCMP_UNE)
3873 return T;
3874 }
3875
3876 return nullptr;
3877}
3878
Sanjay Patel472cc782016-01-11 22:14:42 +00003879/// Given operands for a SelectInst, see if we can fold the result.
3880/// If not, this returns null.
Sanjay Patelac395202018-02-17 14:50:13 +00003881static Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3882 const SimplifyQuery &Q, unsigned MaxRecurse) {
3883 if (auto *CondC = dyn_cast<Constant>(Cond)) {
3884 if (auto *TrueC = dyn_cast<Constant>(TrueVal))
3885 if (auto *FalseC = dyn_cast<Constant>(FalseVal))
3886 return ConstantFoldSelectInstruction(CondC, TrueC, FalseC);
3887
3888 // select undef, X, Y -> X or Y
3889 if (isa<UndefValue>(CondC))
3890 return isa<Constant>(FalseVal) ? FalseVal : TrueVal;
3891
3892 // TODO: Vector constants with undef elements don't simplify.
3893
3894 // select true, X, Y -> X
3895 if (CondC->isAllOnesValue())
Benjamin Kramer5e1794e2014-01-24 17:09:53 +00003896 return TrueVal;
Sanjay Patelac395202018-02-17 14:50:13 +00003897 // select false, X, Y -> Y
3898 if (CondC->isNullValue())
Benjamin Kramer5e1794e2014-01-24 17:09:53 +00003899 return FalseVal;
3900 }
Duncan Sands7e800d62010-11-14 11:23:23 +00003901
Sanjay Patelac395202018-02-17 14:50:13 +00003902 // select ?, X, X -> X
Duncan Sands772749a2011-01-01 20:08:02 +00003903 if (TrueVal == FalseVal)
Chris Lattnerc707fa92010-04-20 05:32:14 +00003904 return TrueVal;
Duncan Sands7e800d62010-11-14 11:23:23 +00003905
Sanjay Patelac395202018-02-17 14:50:13 +00003906 if (isa<UndefValue>(TrueVal)) // select ?, undef, X -> X
Dan Gohman54664ed2011-07-01 01:03:43 +00003907 return FalseVal;
Sanjay Patelac395202018-02-17 14:50:13 +00003908 if (isa<UndefValue>(FalseVal)) // select ?, X, undef -> X
Dan Gohman54664ed2011-07-01 01:03:43 +00003909 return TrueVal;
Duncan Sands7e800d62010-11-14 11:23:23 +00003910
Sanjay Patel5f5eb582016-07-18 20:56:53 +00003911 if (Value *V =
Sanjay Patelac395202018-02-17 14:50:13 +00003912 simplifySelectWithICmpCond(Cond, TrueVal, FalseVal, Q, MaxRecurse))
Sanjay Patel5f5eb582016-07-18 20:56:53 +00003913 return V;
David Majnemerc6a5e1d2014-11-27 06:32:46 +00003914
Sanjay Patel14401072018-11-05 21:51:39 +00003915 if (Value *V = simplifySelectWithFCmp(Cond, TrueVal, FalseVal))
3916 return V;
3917
David Bolvanskyf9476082018-07-28 06:55:51 +00003918 if (Value *V = foldSelectWithBinaryOp(Cond, TrueVal, FalseVal))
3919 return V;
3920
Sanjay Patel7d82d372018-12-02 13:26:03 +00003921 Optional<bool> Imp = isImpliedByDomCondition(Cond, Q.CxtI, Q.DL);
3922 if (Imp)
3923 return *Imp ? TrueVal : FalseVal;
Sanjay Pateld8022702018-11-29 18:44:39 +00003924
Craig Topper9f008862014-04-15 04:59:12 +00003925 return nullptr;
Chris Lattnerc707fa92010-04-20 05:32:14 +00003926}
3927
Duncan Sandsb8cee002012-03-13 11:42:19 +00003928Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00003929 const SimplifyQuery &Q) {
3930 return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Q, RecursionLimit);
Duncan Sandsb8cee002012-03-13 11:42:19 +00003931}
3932
Sanjay Patel472cc782016-01-11 22:14:42 +00003933/// Given operands for an GetElementPtrInst, see if we can fold the result.
3934/// If not, this returns null.
David Blaikie4a2e73b2015-04-02 18:55:32 +00003935static Value *SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00003936 const SimplifyQuery &Q, unsigned) {
Duncan Sands8a0f4862010-11-22 13:42:49 +00003937 // The type of the GEP pointer operand.
David Blaikie4a2e73b2015-04-02 18:55:32 +00003938 unsigned AS =
3939 cast<PointerType>(Ops[0]->getType()->getScalarType())->getAddressSpace();
Duncan Sands8a0f4862010-11-22 13:42:49 +00003940
Chris Lattner8574aba2009-11-27 00:29:05 +00003941 // getelementptr P -> P.
Jay Foadb992a632011-07-19 15:07:52 +00003942 if (Ops.size() == 1)
Chris Lattner8574aba2009-11-27 00:29:05 +00003943 return Ops[0];
3944
Nico Weber48c82402014-08-27 20:06:19 +00003945 // Compute the (pointer) type returned by the GEP instruction.
David Blaikie4a2e73b2015-04-02 18:55:32 +00003946 Type *LastType = GetElementPtrInst::getIndexedType(SrcTy, Ops.slice(1));
Nico Weber48c82402014-08-27 20:06:19 +00003947 Type *GEPTy = PointerType::get(LastType, AS);
3948 if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
3949 GEPTy = VectorType::get(GEPTy, VT->getNumElements());
Davide Italianoa9f047a2017-04-19 14:23:42 +00003950 else if (VectorType *VT = dyn_cast<VectorType>(Ops[1]->getType()))
3951 GEPTy = VectorType::get(GEPTy, VT->getNumElements());
Nico Weber48c82402014-08-27 20:06:19 +00003952
3953 if (isa<UndefValue>(Ops[0]))
Duncan Sands8a0f4862010-11-22 13:42:49 +00003954 return UndefValue::get(GEPTy);
Chris Lattner8574aba2009-11-27 00:29:05 +00003955
Jay Foadb992a632011-07-19 15:07:52 +00003956 if (Ops.size() == 2) {
Duncan Sandscf4bceb2010-11-21 13:53:09 +00003957 // getelementptr P, 0 -> P.
Matthew Simpsonc1c4ad62018-03-15 16:00:29 +00003958 if (match(Ops[1], m_Zero()) && Ops[0]->getType() == GEPTy)
Benjamin Kramer5e1794e2014-01-24 17:09:53 +00003959 return Ops[0];
Nico Weber48c82402014-08-27 20:06:19 +00003960
David Blaikie4a2e73b2015-04-02 18:55:32 +00003961 Type *Ty = SrcTy;
Mehdi Aminia28d91d2015-03-10 02:37:25 +00003962 if (Ty->isSized()) {
Nico Weber48c82402014-08-27 20:06:19 +00003963 Value *P;
3964 uint64_t C;
Mehdi Aminia28d91d2015-03-10 02:37:25 +00003965 uint64_t TyAllocSize = Q.DL.getTypeAllocSize(Ty);
Nico Weber48c82402014-08-27 20:06:19 +00003966 // getelementptr P, N -> P if P points to a type of zero size.
Matthew Simpsonc1c4ad62018-03-15 16:00:29 +00003967 if (TyAllocSize == 0 && Ops[0]->getType() == GEPTy)
Duncan Sandscf4bceb2010-11-21 13:53:09 +00003968 return Ops[0];
Nico Weber48c82402014-08-27 20:06:19 +00003969
3970 // The following transforms are only safe if the ptrtoint cast
3971 // doesn't truncate the pointers.
3972 if (Ops[1]->getType()->getScalarSizeInBits() ==
Elena Demikhovsky945b7e52018-02-14 06:58:08 +00003973 Q.DL.getIndexSizeInBits(AS)) {
Nico Weber48c82402014-08-27 20:06:19 +00003974 auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
3975 if (match(P, m_Zero()))
3976 return Constant::getNullValue(GEPTy);
3977 Value *Temp;
3978 if (match(P, m_PtrToInt(m_Value(Temp))))
David Majnemer11ca2972014-08-27 20:08:34 +00003979 if (Temp->getType() == GEPTy)
3980 return Temp;
Nico Weber48c82402014-08-27 20:06:19 +00003981 return nullptr;
3982 };
3983
3984 // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
3985 if (TyAllocSize == 1 &&
3986 match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
3987 if (Value *R = PtrToIntOrZero(P))
3988 return R;
3989
3990 // getelementptr V, (ashr (sub P, V), C) -> Q
3991 // if P points to a type of size 1 << C.
3992 if (match(Ops[1],
3993 m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3994 m_ConstantInt(C))) &&
3995 TyAllocSize == 1ULL << C)
3996 if (Value *R = PtrToIntOrZero(P))
3997 return R;
3998
3999 // getelementptr V, (sdiv (sub P, V), C) -> Q
4000 // if P points to a type of size C.
4001 if (match(Ops[1],
4002 m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
4003 m_SpecificInt(TyAllocSize))))
4004 if (Value *R = PtrToIntOrZero(P))
4005 return R;
4006 }
Duncan Sandscf4bceb2010-11-21 13:53:09 +00004007 }
4008 }
Duncan Sands7e800d62010-11-14 11:23:23 +00004009
David Majnemerd1501372016-08-07 07:58:12 +00004010 if (Q.DL.getTypeAllocSize(LastType) == 1 &&
4011 all_of(Ops.slice(1).drop_back(1),
4012 [](Value *Idx) { return match(Idx, m_Zero()); })) {
Elena Demikhovsky945b7e52018-02-14 06:58:08 +00004013 unsigned IdxWidth =
4014 Q.DL.getIndexSizeInBits(Ops[0]->getType()->getPointerAddressSpace());
4015 if (Q.DL.getTypeSizeInBits(Ops.back()->getType()) == IdxWidth) {
4016 APInt BasePtrOffset(IdxWidth, 0);
David Majnemerd1501372016-08-07 07:58:12 +00004017 Value *StrippedBasePtr =
4018 Ops[0]->stripAndAccumulateInBoundsConstantOffsets(Q.DL,
4019 BasePtrOffset);
4020
David Majnemer5c5df622016-08-16 06:13:46 +00004021 // gep (gep V, C), (sub 0, V) -> C
David Majnemerd1501372016-08-07 07:58:12 +00004022 if (match(Ops.back(),
4023 m_Sub(m_Zero(), m_PtrToInt(m_Specific(StrippedBasePtr))))) {
4024 auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset);
4025 return ConstantExpr::getIntToPtr(CI, GEPTy);
4026 }
David Majnemer5c5df622016-08-16 06:13:46 +00004027 // gep (gep V, C), (xor V, -1) -> C-1
4028 if (match(Ops.back(),
4029 m_Xor(m_PtrToInt(m_Specific(StrippedBasePtr)), m_AllOnes()))) {
4030 auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset - 1);
4031 return ConstantExpr::getIntToPtr(CI, GEPTy);
4032 }
David Majnemerd1501372016-08-07 07:58:12 +00004033 }
4034 }
4035
Chris Lattner8574aba2009-11-27 00:29:05 +00004036 // Check to see if this is constant foldable.
Craig Topperda8037f2017-06-04 22:41:56 +00004037 if (!all_of(Ops, [](Value *V) { return isa<Constant>(V); }))
4038 return nullptr;
Duncan Sands7e800d62010-11-14 11:23:23 +00004039
Joey Gouly61eaa632017-06-06 10:17:14 +00004040 auto *CE = ConstantExpr::getGetElementPtr(SrcTy, cast<Constant>(Ops[0]),
4041 Ops.slice(1));
4042 if (auto *CEFolded = ConstantFoldConstant(CE, Q.DL))
4043 return CEFolded;
4044 return CE;
Chris Lattner8574aba2009-11-27 00:29:05 +00004045}
4046
Manuel Jacob20c6d5b2016-01-17 22:46:43 +00004047Value *llvm::SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004048 const SimplifyQuery &Q) {
4049 return ::SimplifyGEPInst(SrcTy, Ops, Q, RecursionLimit);
Duncan Sandsb8cee002012-03-13 11:42:19 +00004050}
4051
Sanjay Patel472cc782016-01-11 22:14:42 +00004052/// Given operands for an InsertValueInst, see if we can fold the result.
4053/// If not, this returns null.
Duncan Sandsb8cee002012-03-13 11:42:19 +00004054static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004055 ArrayRef<unsigned> Idxs, const SimplifyQuery &Q,
Duncan Sandsb8cee002012-03-13 11:42:19 +00004056 unsigned) {
Duncan Sandsfd26a952011-09-05 06:52:48 +00004057 if (Constant *CAgg = dyn_cast<Constant>(Agg))
4058 if (Constant *CVal = dyn_cast<Constant>(Val))
4059 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
4060
4061 // insertvalue x, undef, n -> x
4062 if (match(Val, m_Undef()))
4063 return Agg;
4064
4065 // insertvalue x, (extractvalue y, n), n
4066 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
Benjamin Kramer4b79c212011-09-05 18:16:19 +00004067 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
4068 EV->getIndices() == Idxs) {
Duncan Sandsfd26a952011-09-05 06:52:48 +00004069 // insertvalue undef, (extractvalue y, n), n -> y
4070 if (match(Agg, m_Undef()))
4071 return EV->getAggregateOperand();
4072
4073 // insertvalue y, (extractvalue y, n), n -> y
4074 if (Agg == EV->getAggregateOperand())
4075 return Agg;
4076 }
4077
Craig Topper9f008862014-04-15 04:59:12 +00004078 return nullptr;
Duncan Sandsfd26a952011-09-05 06:52:48 +00004079}
4080
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004081Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
4082 ArrayRef<unsigned> Idxs,
4083 const SimplifyQuery &Q) {
4084 return ::SimplifyInsertValueInst(Agg, Val, Idxs, Q, RecursionLimit);
4085}
4086
Igor Laevskye0edb662017-12-13 11:21:18 +00004087Value *llvm::SimplifyInsertElementInst(Value *Vec, Value *Val, Value *Idx,
4088 const SimplifyQuery &Q) {
4089 // Try to constant fold.
4090 auto *VecC = dyn_cast<Constant>(Vec);
4091 auto *ValC = dyn_cast<Constant>(Val);
4092 auto *IdxC = dyn_cast<Constant>(Idx);
4093 if (VecC && ValC && IdxC)
4094 return ConstantFoldInsertElementInstruction(VecC, ValC, IdxC);
4095
4096 // Fold into undef if index is out of bounds.
4097 if (auto *CI = dyn_cast<ConstantInt>(Idx)) {
4098 uint64_t NumElements = cast<VectorType>(Vec->getType())->getNumElements();
Igor Laevskye0edb662017-12-13 11:21:18 +00004099 if (CI->uge(NumElements))
4100 return UndefValue::get(Vec->getType());
4101 }
4102
Philip Reamese499bc32017-12-30 05:54:22 +00004103 // If index is undef, it might be out of bounds (see above case)
4104 if (isa<UndefValue>(Idx))
4105 return UndefValue::get(Vec->getType());
Igor Laevskye0edb662017-12-13 11:21:18 +00004106
Sanjay Patele60cb7d2019-05-23 21:49:47 +00004107 // Inserting an undef scalar? Assume it is the same value as the existing
4108 // vector element.
4109 if (isa<UndefValue>(Val))
4110 return Vec;
4111
Sanjay Patel8869a982019-05-24 00:13:58 +00004112 // If we are extracting a value from a vector, then inserting it into the same
4113 // place, that's the input vector:
4114 // insertelt Vec, (extractelt Vec, Idx), Idx --> Vec
4115 if (match(Val, m_ExtractElement(m_Specific(Vec), m_Specific(Idx))))
4116 return Vec;
4117
Igor Laevskye0edb662017-12-13 11:21:18 +00004118 return nullptr;
4119}
4120
Sanjay Patel472cc782016-01-11 22:14:42 +00004121/// Given operands for an ExtractValueInst, see if we can fold the result.
4122/// If not, this returns null.
David Majnemer25a796e2015-07-13 01:15:46 +00004123static Value *SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004124 const SimplifyQuery &, unsigned) {
David Majnemer25a796e2015-07-13 01:15:46 +00004125 if (auto *CAgg = dyn_cast<Constant>(Agg))
4126 return ConstantFoldExtractValueInstruction(CAgg, Idxs);
4127
4128 // extractvalue x, (insertvalue y, elt, n), n -> elt
4129 unsigned NumIdxs = Idxs.size();
4130 for (auto *IVI = dyn_cast<InsertValueInst>(Agg); IVI != nullptr;
4131 IVI = dyn_cast<InsertValueInst>(IVI->getAggregateOperand())) {
4132 ArrayRef<unsigned> InsertValueIdxs = IVI->getIndices();
4133 unsigned NumInsertValueIdxs = InsertValueIdxs.size();
4134 unsigned NumCommonIdxs = std::min(NumInsertValueIdxs, NumIdxs);
4135 if (InsertValueIdxs.slice(0, NumCommonIdxs) ==
4136 Idxs.slice(0, NumCommonIdxs)) {
4137 if (NumIdxs == NumInsertValueIdxs)
4138 return IVI->getInsertedValueOperand();
4139 break;
4140 }
4141 }
4142
4143 return nullptr;
4144}
4145
4146Value *llvm::SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004147 const SimplifyQuery &Q) {
4148 return ::SimplifyExtractValueInst(Agg, Idxs, Q, RecursionLimit);
4149}
4150
Sanjay Patel472cc782016-01-11 22:14:42 +00004151/// Given operands for an ExtractElementInst, see if we can fold the result.
4152/// If not, this returns null.
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004153static Value *SimplifyExtractElementInst(Value *Vec, Value *Idx, const SimplifyQuery &,
David Majnemer599ca442015-07-13 01:15:53 +00004154 unsigned) {
4155 if (auto *CVec = dyn_cast<Constant>(Vec)) {
4156 if (auto *CIdx = dyn_cast<Constant>(Idx))
4157 return ConstantFoldExtractElementInstruction(CVec, CIdx);
4158
4159 // The index is not relevant if our vector is a splat.
4160 if (auto *Splat = CVec->getSplatValue())
4161 return Splat;
4162
4163 if (isa<UndefValue>(Vec))
4164 return UndefValue::get(Vec->getType()->getVectorElementType());
4165 }
4166
4167 // If extracting a specified index from the vector, see if we can recursively
4168 // find a previously computed scalar that was inserted into the vector.
Philip Reamese499bc32017-12-30 05:54:22 +00004169 if (auto *IdxC = dyn_cast<ConstantInt>(Idx)) {
4170 if (IdxC->getValue().uge(Vec->getType()->getVectorNumElements()))
4171 // definitely out of bounds, thus undefined result
4172 return UndefValue::get(Vec->getType()->getVectorElementType());
4173 if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue()))
4174 return Elt;
4175 }
David Majnemer599ca442015-07-13 01:15:53 +00004176
Zvi Rackover2e6e88f2017-12-06 17:51:46 +00004177 // An undef extract index can be arbitrarily chosen to be an out-of-range
4178 // index value, which would result in the instruction being undef.
4179 if (isa<UndefValue>(Idx))
4180 return UndefValue::get(Vec->getType()->getVectorElementType());
4181
David Majnemer599ca442015-07-13 01:15:53 +00004182 return nullptr;
4183}
4184
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004185Value *llvm::SimplifyExtractElementInst(Value *Vec, Value *Idx,
4186 const SimplifyQuery &Q) {
4187 return ::SimplifyExtractElementInst(Vec, Idx, Q, RecursionLimit);
4188}
4189
Sanjay Patel472cc782016-01-11 22:14:42 +00004190/// See if we can fold the given phi. If not, returns null.
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004191static Value *SimplifyPHINode(PHINode *PN, const SimplifyQuery &Q) {
Duncan Sands7412f6e2010-11-17 04:30:22 +00004192 // If all of the PHI's incoming values are the same then replace the PHI node
4193 // with the common value.
Craig Topper9f008862014-04-15 04:59:12 +00004194 Value *CommonValue = nullptr;
Duncan Sands7412f6e2010-11-17 04:30:22 +00004195 bool HasUndefInput = false;
Pete Cooper833f34d2015-05-12 20:05:31 +00004196 for (Value *Incoming : PN->incoming_values()) {
Duncan Sands7412f6e2010-11-17 04:30:22 +00004197 // If the incoming value is the phi node itself, it can safely be skipped.
4198 if (Incoming == PN) continue;
4199 if (isa<UndefValue>(Incoming)) {
4200 // Remember that we saw an undef value, but otherwise ignore them.
4201 HasUndefInput = true;
4202 continue;
4203 }
4204 if (CommonValue && Incoming != CommonValue)
Craig Topper9f008862014-04-15 04:59:12 +00004205 return nullptr; // Not the same, bail out.
Duncan Sands7412f6e2010-11-17 04:30:22 +00004206 CommonValue = Incoming;
4207 }
4208
4209 // If CommonValue is null then all of the incoming values were either undef or
4210 // equal to the phi node itself.
4211 if (!CommonValue)
4212 return UndefValue::get(PN->getType());
4213
4214 // If we have a PHI node like phi(X, undef, X), where X is defined by some
4215 // instruction, we cannot return X as the result of the PHI node unless it
4216 // dominates the PHI block.
4217 if (HasUndefInput)
Sanjay Patel5da361a2018-04-10 18:38:19 +00004218 return valueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
Duncan Sands7412f6e2010-11-17 04:30:22 +00004219
4220 return CommonValue;
4221}
4222
David Majnemer6774d612016-07-26 17:58:05 +00004223static Value *SimplifyCastInst(unsigned CastOpc, Value *Op,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004224 Type *Ty, const SimplifyQuery &Q, unsigned MaxRecurse) {
David Majnemer126de5d2016-07-25 03:39:21 +00004225 if (auto *C = dyn_cast<Constant>(Op))
David Majnemer6774d612016-07-26 17:58:05 +00004226 return ConstantFoldCastOperand(CastOpc, C, Ty, Q.DL);
Duncan Sands395ac42d2012-03-13 14:07:05 +00004227
David Majnemer6774d612016-07-26 17:58:05 +00004228 if (auto *CI = dyn_cast<CastInst>(Op)) {
4229 auto *Src = CI->getOperand(0);
4230 Type *SrcTy = Src->getType();
4231 Type *MidTy = CI->getType();
4232 Type *DstTy = Ty;
4233 if (Src->getType() == Ty) {
4234 auto FirstOp = static_cast<Instruction::CastOps>(CI->getOpcode());
4235 auto SecondOp = static_cast<Instruction::CastOps>(CastOpc);
4236 Type *SrcIntPtrTy =
4237 SrcTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(SrcTy) : nullptr;
4238 Type *MidIntPtrTy =
4239 MidTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(MidTy) : nullptr;
4240 Type *DstIntPtrTy =
4241 DstTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(DstTy) : nullptr;
4242 if (CastInst::isEliminableCastPair(FirstOp, SecondOp, SrcTy, MidTy, DstTy,
4243 SrcIntPtrTy, MidIntPtrTy,
4244 DstIntPtrTy) == Instruction::BitCast)
4245 return Src;
4246 }
4247 }
David Majnemera90a6212016-07-26 05:52:29 +00004248
4249 // bitcast x -> x
David Majnemer6774d612016-07-26 17:58:05 +00004250 if (CastOpc == Instruction::BitCast)
4251 if (Op->getType() == Ty)
4252 return Op;
David Majnemera90a6212016-07-26 05:52:29 +00004253
4254 return nullptr;
4255}
4256
David Majnemer6774d612016-07-26 17:58:05 +00004257Value *llvm::SimplifyCastInst(unsigned CastOpc, Value *Op, Type *Ty,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004258 const SimplifyQuery &Q) {
4259 return ::SimplifyCastInst(CastOpc, Op, Ty, Q, RecursionLimit);
4260}
4261
Sanjay Patela3c297d2017-04-19 16:48:22 +00004262/// For the given destination element of a shuffle, peek through shuffles to
4263/// match a root vector source operand that contains that element in the same
4264/// vector lane (ie, the same mask index), so we can eliminate the shuffle(s).
4265static Value *foldIdentityShuffles(int DestElt, Value *Op0, Value *Op1,
Zvi Rackover558f86b2017-05-08 15:46:58 +00004266 int MaskVal, Value *RootVec,
Sanjay Patela3c297d2017-04-19 16:48:22 +00004267 unsigned MaxRecurse) {
4268 if (!MaxRecurse--)
4269 return nullptr;
4270
4271 // Bail out if any mask value is undefined. That kind of shuffle may be
4272 // simplified further based on demanded bits or other folds.
Sanjay Patela3c297d2017-04-19 16:48:22 +00004273 if (MaskVal == -1)
4274 return nullptr;
4275
4276 // The mask value chooses which source operand we need to look at next.
Sanjay Patela3c297d2017-04-19 16:48:22 +00004277 int InVecNumElts = Op0->getType()->getVectorNumElements();
Zvi Rackover558f86b2017-05-08 15:46:58 +00004278 int RootElt = MaskVal;
4279 Value *SourceOp = Op0;
4280 if (MaskVal >= InVecNumElts) {
Sanjay Patela3c297d2017-04-19 16:48:22 +00004281 RootElt = MaskVal - InVecNumElts;
4282 SourceOp = Op1;
4283 }
4284
4285 // If the source operand is a shuffle itself, look through it to find the
4286 // matching root vector.
4287 if (auto *SourceShuf = dyn_cast<ShuffleVectorInst>(SourceOp)) {
4288 return foldIdentityShuffles(
4289 DestElt, SourceShuf->getOperand(0), SourceShuf->getOperand(1),
Zvi Rackover558f86b2017-05-08 15:46:58 +00004290 SourceShuf->getMaskValue(RootElt), RootVec, MaxRecurse);
Sanjay Patela3c297d2017-04-19 16:48:22 +00004291 }
4292
4293 // TODO: Look through bitcasts? What if the bitcast changes the vector element
4294 // size?
4295
4296 // The source operand is not a shuffle. Initialize the root vector value for
4297 // this shuffle if that has not been done yet.
4298 if (!RootVec)
4299 RootVec = SourceOp;
4300
4301 // Give up as soon as a source operand does not match the existing root value.
4302 if (RootVec != SourceOp)
4303 return nullptr;
4304
4305 // The element must be coming from the same lane in the source vector
4306 // (although it may have crossed lanes in intermediate shuffles).
4307 if (RootElt != DestElt)
4308 return nullptr;
4309
4310 return RootVec;
4311}
4312
Zvi Rackover8f460652017-04-03 22:05:30 +00004313static Value *SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004314 Type *RetTy, const SimplifyQuery &Q,
Zvi Rackover8f460652017-04-03 22:05:30 +00004315 unsigned MaxRecurse) {
Zvi Rackover4086e132017-04-30 06:06:26 +00004316 if (isa<UndefValue>(Mask))
4317 return UndefValue::get(RetTy);
4318
Zvi Rackover30efd24d2017-04-11 21:37:02 +00004319 Type *InVecTy = Op0->getType();
Zvi Rackover8f460652017-04-03 22:05:30 +00004320 unsigned MaskNumElts = Mask->getType()->getVectorNumElements();
Zvi Rackover30efd24d2017-04-11 21:37:02 +00004321 unsigned InVecNumElts = InVecTy->getVectorNumElements();
Zvi Rackover8f460652017-04-03 22:05:30 +00004322
Zvi Rackover0411e462017-04-30 06:10:54 +00004323 SmallVector<int, 32> Indices;
4324 ShuffleVectorInst::getShuffleMask(Mask, Indices);
4325 assert(MaskNumElts == Indices.size() &&
4326 "Size of Indices not same as number of mask elements?");
4327
Zvi Rackover973ff7c2017-05-07 18:16:37 +00004328 // Canonicalization: If mask does not select elements from an input vector,
4329 // replace that input vector with undef.
Zvi Rackover8f460652017-04-03 22:05:30 +00004330 bool MaskSelects0 = false, MaskSelects1 = false;
4331 for (unsigned i = 0; i != MaskNumElts; ++i) {
Zvi Rackover0411e462017-04-30 06:10:54 +00004332 if (Indices[i] == -1)
Zvi Rackover8f460652017-04-03 22:05:30 +00004333 continue;
Zvi Rackover0411e462017-04-30 06:10:54 +00004334 if ((unsigned)Indices[i] < InVecNumElts)
Zvi Rackover8f460652017-04-03 22:05:30 +00004335 MaskSelects0 = true;
4336 else
4337 MaskSelects1 = true;
4338 }
Zvi Rackover973ff7c2017-05-07 18:16:37 +00004339 if (!MaskSelects0)
4340 Op0 = UndefValue::get(InVecTy);
4341 if (!MaskSelects1)
4342 Op1 = UndefValue::get(InVecTy);
4343
4344 auto *Op0Const = dyn_cast<Constant>(Op0);
4345 auto *Op1Const = dyn_cast<Constant>(Op1);
4346
4347 // If all operands are constant, constant fold the shuffle.
4348 if (Op0Const && Op1Const)
4349 return ConstantFoldShuffleVectorInstruction(Op0Const, Op1Const, Mask);
4350
4351 // Canonicalization: if only one input vector is constant, it shall be the
4352 // second one.
4353 if (Op0Const && !Op1Const) {
4354 std::swap(Op0, Op1);
Zvi Rackoverdfbd3d72017-05-08 12:40:18 +00004355 ShuffleVectorInst::commuteShuffleMask(Indices, InVecNumElts);
Zvi Rackover973ff7c2017-05-07 18:16:37 +00004356 }
Zvi Rackover30efd24d2017-04-11 21:37:02 +00004357
4358 // A shuffle of a splat is always the splat itself. Legal if the shuffle's
4359 // value type is same as the input vectors' type.
4360 if (auto *OpShuf = dyn_cast<ShuffleVectorInst>(Op0))
Zvi Rackover973ff7c2017-05-07 18:16:37 +00004361 if (isa<UndefValue>(Op1) && RetTy == InVecTy &&
Zvi Rackover30efd24d2017-04-11 21:37:02 +00004362 OpShuf->getMask()->getSplatValue())
4363 return Op0;
Zvi Rackover8f460652017-04-03 22:05:30 +00004364
Sanjay Patela3c297d2017-04-19 16:48:22 +00004365 // Don't fold a shuffle with undef mask elements. This may get folded in a
4366 // better way using demanded bits or other analysis.
4367 // TODO: Should we allow this?
Zvi Rackover0411e462017-04-30 06:10:54 +00004368 if (find(Indices, -1) != Indices.end())
4369 return nullptr;
Sanjay Patela3c297d2017-04-19 16:48:22 +00004370
4371 // Check if every element of this shuffle can be mapped back to the
4372 // corresponding element of a single root vector. If so, we don't need this
4373 // shuffle. This handles simple identity shuffles as well as chains of
4374 // shuffles that may widen/narrow and/or move elements across lanes and back.
4375 Value *RootVec = nullptr;
4376 for (unsigned i = 0; i != MaskNumElts; ++i) {
4377 // Note that recursion is limited for each vector element, so if any element
4378 // exceeds the limit, this will fail to simplify.
Zvi Rackover558f86b2017-05-08 15:46:58 +00004379 RootVec =
4380 foldIdentityShuffles(i, Op0, Op1, Indices[i], RootVec, MaxRecurse);
Sanjay Patela3c297d2017-04-19 16:48:22 +00004381
4382 // We can't replace a widening/narrowing shuffle with one of its operands.
4383 if (!RootVec || RootVec->getType() != RetTy)
4384 return nullptr;
4385 }
4386 return RootVec;
Zvi Rackover8f460652017-04-03 22:05:30 +00004387}
4388
4389/// Given operands for a ShuffleVectorInst, fold the result or return null.
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004390Value *llvm::SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask,
4391 Type *RetTy, const SimplifyQuery &Q) {
4392 return ::SimplifyShuffleVectorInst(Op0, Op1, Mask, RetTy, Q, RecursionLimit);
Zvi Rackover8f460652017-04-03 22:05:30 +00004393}
4394
Cameron McInallyc3167692019-05-06 16:05:10 +00004395static Constant *foldConstant(Instruction::UnaryOps Opcode,
4396 Value *&Op, const SimplifyQuery &Q) {
4397 if (auto *C = dyn_cast<Constant>(Op))
4398 return ConstantFoldUnaryOpOperand(Opcode, C, Q.DL);
4399 return nullptr;
4400}
4401
4402/// Given the operand for an FNeg, see if we can fold the result. If not, this
4403/// returns null.
4404static Value *simplifyFNegInst(Value *Op, FastMathFlags FMF,
4405 const SimplifyQuery &Q, unsigned MaxRecurse) {
4406 if (Constant *C = foldConstant(Instruction::FNeg, Op, Q))
4407 return C;
4408
4409 Value *X;
4410 // fneg (fneg X) ==> X
4411 if (match(Op, m_FNeg(m_Value(X))))
4412 return X;
4413
4414 return nullptr;
4415}
4416
4417Value *llvm::SimplifyFNegInst(Value *Op, FastMathFlags FMF,
4418 const SimplifyQuery &Q) {
4419 return ::simplifyFNegInst(Op, FMF, Q, RecursionLimit);
4420}
4421
Sanjay Patele2359422018-03-21 19:31:53 +00004422static Constant *propagateNaN(Constant *In) {
4423 // If the input is a vector with undef elements, just return a default NaN.
4424 if (!In->isNaN())
4425 return ConstantFP::getNaN(In->getType());
4426
4427 // Propagate the existing NaN constant when possible.
4428 // TODO: Should we quiet a signaling NaN?
4429 return In;
4430}
4431
4432static Constant *simplifyFPBinop(Value *Op0, Value *Op1) {
4433 if (isa<UndefValue>(Op0) || isa<UndefValue>(Op1))
4434 return ConstantFP::getNaN(Op0->getType());
4435
4436 if (match(Op0, m_NaN()))
4437 return propagateNaN(cast<Constant>(Op0));
4438 if (match(Op1, m_NaN()))
4439 return propagateNaN(cast<Constant>(Op1));
4440
4441 return nullptr;
4442}
4443
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004444/// Given operands for an FAdd, see if we can fold the result. If not, this
4445/// returns null.
4446static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4447 const SimplifyQuery &Q, unsigned MaxRecurse) {
4448 if (Constant *C = foldOrCommuteConstant(Instruction::FAdd, Op0, Op1, Q))
4449 return C;
4450
Sanjay Patele2359422018-03-21 19:31:53 +00004451 if (Constant *C = simplifyFPBinop(Op0, Op1))
4452 return C;
Sanjay Patel42227162018-03-10 16:51:28 +00004453
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004454 // fadd X, -0 ==> X
Sanjay Patel93e64dd2018-03-25 21:16:33 +00004455 if (match(Op1, m_NegZeroFP()))
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004456 return Op0;
4457
4458 // fadd X, 0 ==> X, when we know X is not -0
Sanjay Patel93e64dd2018-03-25 21:16:33 +00004459 if (match(Op1, m_PosZeroFP()) &&
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004460 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
4461 return Op0;
4462
Cameron McInally0c82d9b2019-05-15 14:31:33 +00004463 // With nnan: -X + X --> 0.0 (and commuted variant)
Sanjay Patel11f7f992018-03-14 21:23:27 +00004464 // We don't have to explicitly exclude infinities (ninf): INF + -INF == NaN.
4465 // Negative zeros are allowed because we always end up with positive zero:
4466 // X = -0.0: (-0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
4467 // X = -0.0: ( 0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
4468 // X = 0.0: (-0.0 - ( 0.0)) + ( 0.0) == (-0.0) + ( 0.0) == 0.0
4469 // X = 0.0: ( 0.0 - ( 0.0)) + ( 0.0) == ( 0.0) + ( 0.0) == 0.0
Cameron McInally0c82d9b2019-05-15 14:31:33 +00004470 if (FMF.noNaNs()) {
4471 if (match(Op0, m_FSub(m_AnyZeroFP(), m_Specific(Op1))) ||
4472 match(Op1, m_FSub(m_AnyZeroFP(), m_Specific(Op0))))
4473 return ConstantFP::getNullValue(Op0->getType());
4474
4475 if (match(Op0, m_FNeg(m_Specific(Op1))) ||
4476 match(Op1, m_FNeg(m_Specific(Op0))))
4477 return ConstantFP::getNullValue(Op0->getType());
4478 }
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004479
Sanjay Patel9b073472018-08-07 20:32:55 +00004480 // (X - Y) + Y --> X
4481 // Y + (X - Y) --> X
4482 Value *X;
4483 if (FMF.noSignedZeros() && FMF.allowReassoc() &&
4484 (match(Op0, m_FSub(m_Value(X), m_Specific(Op1))) ||
4485 match(Op1, m_FSub(m_Value(X), m_Specific(Op0)))))
4486 return X;
4487
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004488 return nullptr;
4489}
4490
4491/// Given operands for an FSub, see if we can fold the result. If not, this
4492/// returns null.
4493static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4494 const SimplifyQuery &Q, unsigned MaxRecurse) {
4495 if (Constant *C = foldOrCommuteConstant(Instruction::FSub, Op0, Op1, Q))
4496 return C;
4497
Sanjay Patele2359422018-03-21 19:31:53 +00004498 if (Constant *C = simplifyFPBinop(Op0, Op1))
4499 return C;
Sanjay Patel42227162018-03-10 16:51:28 +00004500
Sanjay Patel93e64dd2018-03-25 21:16:33 +00004501 // fsub X, +0 ==> X
4502 if (match(Op1, m_PosZeroFP()))
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004503 return Op0;
4504
4505 // fsub X, -0 ==> X, when we know X is not -0
Sanjay Patel93e64dd2018-03-25 21:16:33 +00004506 if (match(Op1, m_NegZeroFP()) &&
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004507 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
4508 return Op0;
4509
4510 // fsub -0.0, (fsub -0.0, X) ==> X
Cameron McInally2d2a46d2019-05-20 13:13:35 +00004511 // fsub -0.0, (fneg X) ==> X
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004512 Value *X;
Sanjay Patel93e64dd2018-03-25 21:16:33 +00004513 if (match(Op0, m_NegZeroFP()) &&
Cameron McInally2d2a46d2019-05-20 13:13:35 +00004514 match(Op1, m_FNeg(m_Value(X))))
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004515 return X;
4516
4517 // fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored.
Cameron McInally067e9462019-05-17 16:47:00 +00004518 // fsub 0.0, (fneg X) ==> X if signed zeros are ignored.
Sanjay Patela4f42f22018-03-15 14:29:27 +00004519 if (FMF.noSignedZeros() && match(Op0, m_AnyZeroFP()) &&
Cameron McInally067e9462019-05-17 16:47:00 +00004520 (match(Op1, m_FSub(m_AnyZeroFP(), m_Value(X))) ||
4521 match(Op1, m_FNeg(m_Value(X)))))
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004522 return X;
4523
4524 // fsub nnan x, x ==> 0.0
4525 if (FMF.noNaNs() && Op0 == Op1)
4526 return Constant::getNullValue(Op0->getType());
4527
Sanjay Patelf7a8fb22018-08-07 20:14:27 +00004528 // Y - (Y - X) --> X
Sanjay Patel4364d602018-08-07 20:23:49 +00004529 // (X + Y) - Y --> X
Sanjay Patelf7a8fb22018-08-07 20:14:27 +00004530 if (FMF.noSignedZeros() && FMF.allowReassoc() &&
Sanjay Patel4364d602018-08-07 20:23:49 +00004531 (match(Op1, m_FSub(m_Specific(Op0), m_Value(X))) ||
4532 match(Op0, m_c_FAdd(m_Specific(Op1), m_Value(X)))))
Sanjay Patelf7a8fb22018-08-07 20:14:27 +00004533 return X;
4534
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004535 return nullptr;
4536}
4537
4538/// Given the operands for an FMul, see if we can fold the result
4539static Value *SimplifyFMulInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4540 const SimplifyQuery &Q, unsigned MaxRecurse) {
4541 if (Constant *C = foldOrCommuteConstant(Instruction::FMul, Op0, Op1, Q))
4542 return C;
4543
Sanjay Patele2359422018-03-21 19:31:53 +00004544 if (Constant *C = simplifyFPBinop(Op0, Op1))
4545 return C;
Sanjay Patel42227162018-03-10 16:51:28 +00004546
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004547 // fmul X, 1.0 ==> X
4548 if (match(Op1, m_FPOne()))
4549 return Op0;
4550
4551 // fmul nnan nsz X, 0 ==> 0
Sanjay Patela4f42f22018-03-15 14:29:27 +00004552 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZeroFP()))
4553 return ConstantFP::getNullValue(Op0->getType());
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004554
Sanjay Patel95ec4a42018-03-18 14:12:25 +00004555 // sqrt(X) * sqrt(X) --> X, if we can:
4556 // 1. Remove the intermediate rounding (reassociate).
4557 // 2. Ignore non-zero negative numbers because sqrt would produce NAN.
4558 // 3. Ignore -0.0 because sqrt(-0.0) == -0.0, but -0.0 * -0.0 == 0.0.
Sanjay Pateldb53d182018-02-23 22:20:13 +00004559 Value *X;
Sanjay Patel95ec4a42018-03-18 14:12:25 +00004560 if (Op0 == Op1 && match(Op0, m_Intrinsic<Intrinsic::sqrt>(m_Value(X))) &&
4561 FMF.allowReassoc() && FMF.noNaNs() && FMF.noSignedZeros())
Sanjay Pateldb53d182018-02-23 22:20:13 +00004562 return X;
4563
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004564 return nullptr;
4565}
4566
4567Value *llvm::SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4568 const SimplifyQuery &Q) {
4569 return ::SimplifyFAddInst(Op0, Op1, FMF, Q, RecursionLimit);
4570}
4571
4572
4573Value *llvm::SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4574 const SimplifyQuery &Q) {
4575 return ::SimplifyFSubInst(Op0, Op1, FMF, Q, RecursionLimit);
4576}
4577
4578Value *llvm::SimplifyFMulInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4579 const SimplifyQuery &Q) {
4580 return ::SimplifyFMulInst(Op0, Op1, FMF, Q, RecursionLimit);
4581}
4582
4583static Value *SimplifyFDivInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4584 const SimplifyQuery &Q, unsigned) {
4585 if (Constant *C = foldOrCommuteConstant(Instruction::FDiv, Op0, Op1, Q))
4586 return C;
4587
Sanjay Patele2359422018-03-21 19:31:53 +00004588 if (Constant *C = simplifyFPBinop(Op0, Op1))
4589 return C;
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004590
4591 // X / 1.0 -> X
4592 if (match(Op1, m_FPOne()))
4593 return Op0;
4594
4595 // 0 / X -> 0
4596 // Requires that NaNs are off (X could be zero) and signed zeroes are
4597 // ignored (X could be positive or negative, so the output sign is unknown).
Sanjay Patela4f42f22018-03-15 14:29:27 +00004598 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZeroFP()))
4599 return ConstantFP::getNullValue(Op0->getType());
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004600
4601 if (FMF.noNaNs()) {
4602 // X / X -> 1.0 is legal when NaNs are ignored.
Sanjay Patel83f05662018-01-30 00:18:37 +00004603 // We can ignore infinities because INF/INF is NaN.
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004604 if (Op0 == Op1)
4605 return ConstantFP::get(Op0->getType(), 1.0);
4606
Sanjay Patel83f05662018-01-30 00:18:37 +00004607 // (X * Y) / Y --> X if we can reassociate to the above form.
4608 Value *X;
4609 if (FMF.allowReassoc() && match(Op0, m_c_FMul(m_Value(X), m_Specific(Op1))))
4610 return X;
4611
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004612 // -X / X -> -1.0 and
4613 // X / -X -> -1.0 are legal when NaNs are ignored.
4614 // We can ignore signed zeros because +-0.0/+-0.0 is NaN and ignored.
Cameron McInallybea59672018-10-09 21:48:00 +00004615 if (match(Op0, m_FNegNSZ(m_Specific(Op1))) ||
4616 match(Op1, m_FNegNSZ(m_Specific(Op0))))
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004617 return ConstantFP::get(Op0->getType(), -1.0);
4618 }
4619
4620 return nullptr;
4621}
4622
4623Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4624 const SimplifyQuery &Q) {
4625 return ::SimplifyFDivInst(Op0, Op1, FMF, Q, RecursionLimit);
4626}
4627
4628static Value *SimplifyFRemInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4629 const SimplifyQuery &Q, unsigned) {
4630 if (Constant *C = foldOrCommuteConstant(Instruction::FRem, Op0, Op1, Q))
4631 return C;
4632
Sanjay Patele2359422018-03-21 19:31:53 +00004633 if (Constant *C = simplifyFPBinop(Op0, Op1))
4634 return C;
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004635
Sanjay Patel8f063d02018-03-15 14:04:31 +00004636 // Unlike fdiv, the result of frem always matches the sign of the dividend.
4637 // The constant match may include undef elements in a vector, so return a full
4638 // zero constant as the result.
4639 if (FMF.noNaNs()) {
Sanjay Patel93e64dd2018-03-25 21:16:33 +00004640 // +0 % X -> 0
4641 if (match(Op0, m_PosZeroFP()))
Sanjay Patel8f063d02018-03-15 14:04:31 +00004642 return ConstantFP::getNullValue(Op0->getType());
4643 // -0 % X -> -0
Sanjay Patel93e64dd2018-03-25 21:16:33 +00004644 if (match(Op0, m_NegZeroFP()))
Sanjay Patel8f063d02018-03-15 14:04:31 +00004645 return ConstantFP::getNegativeZero(Op0->getType());
4646 }
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004647
4648 return nullptr;
4649}
4650
4651Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4652 const SimplifyQuery &Q) {
4653 return ::SimplifyFRemInst(Op0, Op1, FMF, Q, RecursionLimit);
4654}
4655
Chris Lattnera71e9d62009-11-10 00:55:12 +00004656//=== Helper functions for higher up the class hierarchy.
Chris Lattnerc1f19072009-11-09 23:28:39 +00004657
Cameron McInallyc3167692019-05-06 16:05:10 +00004658/// Given the operand for a UnaryOperator, see if we can fold the result.
4659/// If not, this returns null.
4660static Value *simplifyUnOp(unsigned Opcode, Value *Op, const SimplifyQuery &Q,
4661 unsigned MaxRecurse) {
4662 switch (Opcode) {
4663 case Instruction::FNeg:
4664 return simplifyFNegInst(Op, FastMathFlags(), Q, MaxRecurse);
4665 default:
4666 llvm_unreachable("Unexpected opcode");
4667 }
4668}
4669
4670/// Given the operand for a UnaryOperator, see if we can fold the result.
4671/// If not, this returns null.
Jay Foad565c5432019-07-24 12:50:10 +00004672/// Try to use FastMathFlags when folding the result.
Cameron McInallyc3167692019-05-06 16:05:10 +00004673static Value *simplifyFPUnOp(unsigned Opcode, Value *Op,
4674 const FastMathFlags &FMF,
4675 const SimplifyQuery &Q, unsigned MaxRecurse) {
4676 switch (Opcode) {
4677 case Instruction::FNeg:
4678 return simplifyFNegInst(Op, FMF, Q, MaxRecurse);
4679 default:
4680 return simplifyUnOp(Opcode, Op, Q, MaxRecurse);
4681 }
4682}
4683
Craig Topperb457e432019-05-31 08:10:23 +00004684Value *llvm::SimplifyUnOp(unsigned Opcode, Value *Op, const SimplifyQuery &Q) {
4685 return ::simplifyUnOp(Opcode, Op, Q, RecursionLimit);
4686}
4687
Jay Foad565c5432019-07-24 12:50:10 +00004688Value *llvm::SimplifyUnOp(unsigned Opcode, Value *Op, FastMathFlags FMF,
4689 const SimplifyQuery &Q) {
Cameron McInallyc3167692019-05-06 16:05:10 +00004690 return ::simplifyFPUnOp(Opcode, Op, FMF, Q, RecursionLimit);
4691}
4692
Sanjay Patel472cc782016-01-11 22:14:42 +00004693/// Given operands for a BinaryOperator, see if we can fold the result.
4694/// If not, this returns null.
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00004695static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004696 const SimplifyQuery &Q, unsigned MaxRecurse) {
Chris Lattnera71e9d62009-11-10 00:55:12 +00004697 switch (Opcode) {
Chris Lattner9e4aa022011-02-09 17:15:04 +00004698 case Instruction::Add:
Sanjay Patel1fd16f02017-04-01 18:40:30 +00004699 return SimplifyAddInst(LHS, RHS, false, false, Q, MaxRecurse);
Chris Lattner9e4aa022011-02-09 17:15:04 +00004700 case Instruction::Sub:
Sanjay Patel1fd16f02017-04-01 18:40:30 +00004701 return SimplifySubInst(LHS, RHS, false, false, Q, MaxRecurse);
Sanjay Patel1fd16f02017-04-01 18:40:30 +00004702 case Instruction::Mul:
4703 return SimplifyMulInst(LHS, RHS, Q, MaxRecurse);
Sanjay Patel1fd16f02017-04-01 18:40:30 +00004704 case Instruction::SDiv:
4705 return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
4706 case Instruction::UDiv:
4707 return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
Sanjay Patel1fd16f02017-04-01 18:40:30 +00004708 case Instruction::SRem:
4709 return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
4710 case Instruction::URem:
4711 return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
Chris Lattner9e4aa022011-02-09 17:15:04 +00004712 case Instruction::Shl:
Sanjay Patel1fd16f02017-04-01 18:40:30 +00004713 return SimplifyShlInst(LHS, RHS, false, false, Q, MaxRecurse);
Chris Lattner9e4aa022011-02-09 17:15:04 +00004714 case Instruction::LShr:
Sanjay Patel1fd16f02017-04-01 18:40:30 +00004715 return SimplifyLShrInst(LHS, RHS, false, Q, MaxRecurse);
Chris Lattner9e4aa022011-02-09 17:15:04 +00004716 case Instruction::AShr:
Sanjay Patel1fd16f02017-04-01 18:40:30 +00004717 return SimplifyAShrInst(LHS, RHS, false, Q, MaxRecurse);
4718 case Instruction::And:
4719 return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
4720 case Instruction::Or:
4721 return SimplifyOrInst(LHS, RHS, Q, MaxRecurse);
4722 case Instruction::Xor:
4723 return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
Sanjay Patelfa877fd2017-09-11 13:34:27 +00004724 case Instruction::FAdd:
4725 return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4726 case Instruction::FSub:
4727 return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4728 case Instruction::FMul:
4729 return SimplifyFMulInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4730 case Instruction::FDiv:
4731 return SimplifyFDivInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4732 case Instruction::FRem:
4733 return SimplifyFRemInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
Chris Lattnera71e9d62009-11-10 00:55:12 +00004734 default:
Craig Topper8ef20ea2017-04-06 18:59:08 +00004735 llvm_unreachable("Unexpected opcode");
Chris Lattnera71e9d62009-11-10 00:55:12 +00004736 }
4737}
Chris Lattnerc1f19072009-11-09 23:28:39 +00004738
Sanjay Patel472cc782016-01-11 22:14:42 +00004739/// Given operands for a BinaryOperator, see if we can fold the result.
4740/// If not, this returns null.
Jay Foad565c5432019-07-24 12:50:10 +00004741/// Try to use FastMathFlags when folding the result.
4742static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4743 const FastMathFlags &FMF, const SimplifyQuery &Q,
4744 unsigned MaxRecurse) {
Michael Zolotukhin4e8598e2015-02-06 20:02:51 +00004745 switch (Opcode) {
4746 case Instruction::FAdd:
4747 return SimplifyFAddInst(LHS, RHS, FMF, Q, MaxRecurse);
4748 case Instruction::FSub:
4749 return SimplifyFSubInst(LHS, RHS, FMF, Q, MaxRecurse);
4750 case Instruction::FMul:
4751 return SimplifyFMulInst(LHS, RHS, FMF, Q, MaxRecurse);
Zia Ansari394cef82016-12-08 23:27:40 +00004752 case Instruction::FDiv:
4753 return SimplifyFDivInst(LHS, RHS, FMF, Q, MaxRecurse);
Michael Zolotukhin4e8598e2015-02-06 20:02:51 +00004754 default:
4755 return SimplifyBinOp(Opcode, LHS, RHS, Q, MaxRecurse);
4756 }
4757}
4758
Duncan Sands7e800d62010-11-14 11:23:23 +00004759Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004760 const SimplifyQuery &Q) {
4761 return ::SimplifyBinOp(Opcode, LHS, RHS, Q, RecursionLimit);
4762}
4763
Jay Foad565c5432019-07-24 12:50:10 +00004764Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4765 FastMathFlags FMF, const SimplifyQuery &Q) {
4766 return ::SimplifyBinOp(Opcode, LHS, RHS, FMF, Q, RecursionLimit);
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004767}
4768
Sanjay Patel472cc782016-01-11 22:14:42 +00004769/// Given operands for a CmpInst, see if we can fold the result.
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00004770static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004771 const SimplifyQuery &Q, unsigned MaxRecurse) {
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00004772 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
Duncan Sandsb8cee002012-03-13 11:42:19 +00004773 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
Benjamin Kramerf4ebfa32015-07-10 14:02:02 +00004774 return SimplifyFCmpInst(Predicate, LHS, RHS, FastMathFlags(), Q, MaxRecurse);
Duncan Sandsf3b1bf12010-11-10 18:23:01 +00004775}
4776
4777Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00004778 const SimplifyQuery &Q) {
4779 return ::SimplifyCmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
4780}
4781
Michael Ilseman54857292013-02-07 19:26:05 +00004782static bool IsIdempotent(Intrinsic::ID ID) {
4783 switch (ID) {
4784 default: return false;
4785
4786 // Unary idempotent: f(f(x)) = f(x)
4787 case Intrinsic::fabs:
4788 case Intrinsic::floor:
4789 case Intrinsic::ceil:
4790 case Intrinsic::trunc:
4791 case Intrinsic::rint:
4792 case Intrinsic::nearbyint:
Hal Finkel171817e2013-08-07 22:49:12 +00004793 case Intrinsic::round:
Matt Arsenault3ced3d92017-09-07 01:21:43 +00004794 case Intrinsic::canonicalize:
Michael Ilseman54857292013-02-07 19:26:05 +00004795 return true;
4796 }
4797}
4798
Peter Collingbourne7dd8dbf2016-04-22 21:18:02 +00004799static Value *SimplifyRelativeLoad(Constant *Ptr, Constant *Offset,
4800 const DataLayout &DL) {
4801 GlobalValue *PtrSym;
4802 APInt PtrOffset;
4803 if (!IsConstantOffsetFromGlobal(Ptr, PtrSym, PtrOffset, DL))
4804 return nullptr;
4805
4806 Type *Int8PtrTy = Type::getInt8PtrTy(Ptr->getContext());
4807 Type *Int32Ty = Type::getInt32Ty(Ptr->getContext());
4808 Type *Int32PtrTy = Int32Ty->getPointerTo();
4809 Type *Int64Ty = Type::getInt64Ty(Ptr->getContext());
4810
4811 auto *OffsetConstInt = dyn_cast<ConstantInt>(Offset);
4812 if (!OffsetConstInt || OffsetConstInt->getType()->getBitWidth() > 64)
4813 return nullptr;
4814
4815 uint64_t OffsetInt = OffsetConstInt->getSExtValue();
4816 if (OffsetInt % 4 != 0)
4817 return nullptr;
4818
4819 Constant *C = ConstantExpr::getGetElementPtr(
4820 Int32Ty, ConstantExpr::getBitCast(Ptr, Int32PtrTy),
4821 ConstantInt::get(Int64Ty, OffsetInt / 4));
4822 Constant *Loaded = ConstantFoldLoadFromConstPtr(C, Int32Ty, DL);
4823 if (!Loaded)
4824 return nullptr;
4825
4826 auto *LoadedCE = dyn_cast<ConstantExpr>(Loaded);
4827 if (!LoadedCE)
4828 return nullptr;
4829
4830 if (LoadedCE->getOpcode() == Instruction::Trunc) {
4831 LoadedCE = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4832 if (!LoadedCE)
4833 return nullptr;
4834 }
4835
4836 if (LoadedCE->getOpcode() != Instruction::Sub)
4837 return nullptr;
4838
4839 auto *LoadedLHS = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4840 if (!LoadedLHS || LoadedLHS->getOpcode() != Instruction::PtrToInt)
4841 return nullptr;
4842 auto *LoadedLHSPtr = LoadedLHS->getOperand(0);
4843
4844 Constant *LoadedRHS = LoadedCE->getOperand(1);
4845 GlobalValue *LoadedRHSSym;
4846 APInt LoadedRHSOffset;
4847 if (!IsConstantOffsetFromGlobal(LoadedRHS, LoadedRHSSym, LoadedRHSOffset,
4848 DL) ||
4849 PtrSym != LoadedRHSSym || PtrOffset != LoadedRHSOffset)
4850 return nullptr;
4851
4852 return ConstantExpr::getBitCast(LoadedLHSPtr, Int8PtrTy);
4853}
4854
Sanjay Patelf52eeb12018-07-29 14:42:08 +00004855static Value *simplifyUnaryIntrinsic(Function *F, Value *Op0,
4856 const SimplifyQuery &Q) {
4857 // Idempotent functions return the same result when called repeatedly.
David Majnemer15032582015-05-22 03:56:46 +00004858 Intrinsic::ID IID = F->getIntrinsicID();
Sanjay Patelf52eeb12018-07-29 14:42:08 +00004859 if (IsIdempotent(IID))
4860 if (auto *II = dyn_cast<IntrinsicInst>(Op0))
4861 if (II->getIntrinsicID() == IID)
4862 return II;
Michael Ilseman54857292013-02-07 19:26:05 +00004863
Sanjay Patelf52eeb12018-07-29 14:42:08 +00004864 Value *X;
4865 switch (IID) {
4866 case Intrinsic::fabs:
4867 if (SignBitMustBeZero(Op0, Q.TLI)) return Op0;
4868 break;
4869 case Intrinsic::bswap:
4870 // bswap(bswap(x)) -> x
4871 if (match(Op0, m_BSwap(m_Value(X)))) return X;
4872 break;
4873 case Intrinsic::bitreverse:
4874 // bitreverse(bitreverse(x)) -> x
4875 if (match(Op0, m_BitReverse(m_Value(X)))) return X;
4876 break;
4877 case Intrinsic::exp:
4878 // exp(log(x)) -> x
4879 if (Q.CxtI->hasAllowReassoc() &&
4880 match(Op0, m_Intrinsic<Intrinsic::log>(m_Value(X)))) return X;
4881 break;
4882 case Intrinsic::exp2:
4883 // exp2(log2(x)) -> x
4884 if (Q.CxtI->hasAllowReassoc() &&
4885 match(Op0, m_Intrinsic<Intrinsic::log2>(m_Value(X)))) return X;
4886 break;
4887 case Intrinsic::log:
4888 // log(exp(x)) -> x
4889 if (Q.CxtI->hasAllowReassoc() &&
4890 match(Op0, m_Intrinsic<Intrinsic::exp>(m_Value(X)))) return X;
4891 break;
4892 case Intrinsic::log2:
4893 // log2(exp2(x)) -> x
4894 if (Q.CxtI->hasAllowReassoc() &&
Dmitry Venikovaaa709f2019-02-03 03:48:30 +00004895 (match(Op0, m_Intrinsic<Intrinsic::exp2>(m_Value(X))) ||
4896 match(Op0, m_Intrinsic<Intrinsic::pow>(m_SpecificFP(2.0),
4897 m_Value(X))))) return X;
4898 break;
4899 case Intrinsic::log10:
4900 // log10(pow(10.0, x)) -> x
4901 if (Q.CxtI->hasAllowReassoc() &&
4902 match(Op0, m_Intrinsic<Intrinsic::pow>(m_SpecificFP(10.0),
4903 m_Value(X)))) return X;
Sanjay Patelf52eeb12018-07-29 14:42:08 +00004904 break;
Matt Arsenault03e749282019-04-03 00:25:06 +00004905 case Intrinsic::floor:
4906 case Intrinsic::trunc:
4907 case Intrinsic::ceil:
4908 case Intrinsic::round:
4909 case Intrinsic::nearbyint:
4910 case Intrinsic::rint: {
4911 // floor (sitofp x) -> sitofp x
4912 // floor (uitofp x) -> uitofp x
4913 //
4914 // Converting from int always results in a finite integral number or
4915 // infinity. For either of those inputs, these rounding functions always
4916 // return the same value, so the rounding can be eliminated.
4917 if (match(Op0, m_SIToFP(m_Value())) || match(Op0, m_UIToFP(m_Value())))
4918 return Op0;
4919 break;
4920 }
Sanjay Patelf52eeb12018-07-29 14:42:08 +00004921 default:
4922 break;
Matt Arsenault1e0edbf2017-01-11 00:33:24 +00004923 }
Michael Ilseman54857292013-02-07 19:26:05 +00004924
Sanjay Patelf52eeb12018-07-29 14:42:08 +00004925 return nullptr;
4926}
Matt Arsenault82606662017-01-11 00:57:54 +00004927
Sanjay Patelf52eeb12018-07-29 14:42:08 +00004928static Value *simplifyBinaryIntrinsic(Function *F, Value *Op0, Value *Op1,
4929 const SimplifyQuery &Q) {
4930 Intrinsic::ID IID = F->getIntrinsicID();
4931 Type *ReturnType = F->getReturnType();
4932 switch (IID) {
4933 case Intrinsic::usub_with_overflow:
4934 case Intrinsic::ssub_with_overflow:
4935 // X - X -> { 0, false }
4936 if (Op0 == Op1)
4937 return Constant::getNullValue(ReturnType);
Roman Lebedev5a663bd2019-06-16 20:39:45 +00004938 LLVM_FALLTHROUGH;
Sanjay Patelf52eeb12018-07-29 14:42:08 +00004939 case Intrinsic::uadd_with_overflow:
4940 case Intrinsic::sadd_with_overflow:
Roman Lebedev5a663bd2019-06-16 20:39:45 +00004941 // X - undef -> { undef, false }
4942 // undef - X -> { undef, false }
4943 // X + undef -> { undef, false }
4944 // undef + x -> { undef, false }
4945 if (isa<UndefValue>(Op0) || isa<UndefValue>(Op1)) {
4946 return ConstantStruct::get(
4947 cast<StructType>(ReturnType),
4948 {UndefValue::get(ReturnType->getStructElementType(0)),
4949 Constant::getNullValue(ReturnType->getStructElementType(1))});
4950 }
Sanjay Patelf52eeb12018-07-29 14:42:08 +00004951 break;
4952 case Intrinsic::umul_with_overflow:
4953 case Intrinsic::smul_with_overflow:
4954 // 0 * X -> { 0, false }
4955 // X * 0 -> { 0, false }
4956 if (match(Op0, m_Zero()) || match(Op1, m_Zero()))
4957 return Constant::getNullValue(ReturnType);
4958 // undef * X -> { 0, false }
4959 // X * undef -> { 0, false }
4960 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
4961 return Constant::getNullValue(ReturnType);
4962 break;
Sanjay Pateleea21da2018-11-20 17:20:26 +00004963 case Intrinsic::uadd_sat:
4964 // sat(MAX + X) -> MAX
4965 // sat(X + MAX) -> MAX
4966 if (match(Op0, m_AllOnes()) || match(Op1, m_AllOnes()))
4967 return Constant::getAllOnesValue(ReturnType);
4968 LLVM_FALLTHROUGH;
4969 case Intrinsic::sadd_sat:
4970 // sat(X + undef) -> -1
4971 // sat(undef + X) -> -1
4972 // For unsigned: Assume undef is MAX, thus we saturate to MAX (-1).
4973 // For signed: Assume undef is ~X, in which case X + ~X = -1.
4974 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
4975 return Constant::getAllOnesValue(ReturnType);
4976
4977 // X + 0 -> X
4978 if (match(Op1, m_Zero()))
4979 return Op0;
4980 // 0 + X -> X
4981 if (match(Op0, m_Zero()))
4982 return Op1;
4983 break;
4984 case Intrinsic::usub_sat:
4985 // sat(0 - X) -> 0, sat(X - MAX) -> 0
4986 if (match(Op0, m_Zero()) || match(Op1, m_AllOnes()))
4987 return Constant::getNullValue(ReturnType);
4988 LLVM_FALLTHROUGH;
4989 case Intrinsic::ssub_sat:
4990 // X - X -> 0, X - undef -> 0, undef - X -> 0
4991 if (Op0 == Op1 || match(Op0, m_Undef()) || match(Op1, m_Undef()))
4992 return Constant::getNullValue(ReturnType);
4993 // X - 0 -> X
4994 if (match(Op1, m_Zero()))
4995 return Op0;
4996 break;
Sanjay Patelf52eeb12018-07-29 14:42:08 +00004997 case Intrinsic::load_relative:
4998 if (auto *C0 = dyn_cast<Constant>(Op0))
4999 if (auto *C1 = dyn_cast<Constant>(Op1))
Matt Arsenault82606662017-01-11 00:57:54 +00005000 return SimplifyRelativeLoad(C0, C1, Q.DL);
Sanjay Patelf52eeb12018-07-29 14:42:08 +00005001 break;
5002 case Intrinsic::powi:
5003 if (auto *Power = dyn_cast<ConstantInt>(Op1)) {
5004 // powi(x, 0) -> 1.0
5005 if (Power->isZero())
5006 return ConstantFP::get(Op0->getType(), 1.0);
5007 // powi(x, 1) -> x
5008 if (Power->isOne())
5009 return Op0;
Matt Arsenault82606662017-01-11 00:57:54 +00005010 }
Sanjay Patelf52eeb12018-07-29 14:42:08 +00005011 break;
5012 case Intrinsic::maxnum:
Thomas Livelyc3392502018-10-19 19:01:26 +00005013 case Intrinsic::minnum:
5014 case Intrinsic::maximum:
5015 case Intrinsic::minimum: {
Sanjay Patel28c7e412018-08-01 23:05:55 +00005016 // If the arguments are the same, this is a no-op.
5017 if (Op0 == Op1) return Op0;
5018
Thomas Livelyc3392502018-10-19 19:01:26 +00005019 // If one argument is undef, return the other argument.
5020 if (match(Op0, m_Undef()))
5021 return Op1;
5022 if (match(Op1, m_Undef()))
5023 return Op0;
5024
5025 // If one argument is NaN, return other or NaN appropriately.
5026 bool PropagateNaN = IID == Intrinsic::minimum || IID == Intrinsic::maximum;
5027 if (match(Op0, m_NaN()))
5028 return PropagateNaN ? Op0 : Op1;
5029 if (match(Op1, m_NaN()))
5030 return PropagateNaN ? Op1 : Op0;
Sanjay Patel3f6e9a72018-08-02 14:33:40 +00005031
Sanjay Patel948ff872018-08-07 14:36:27 +00005032 // Min/max of the same operation with common operand:
5033 // m(m(X, Y)), X --> m(X, Y) (4 commuted variants)
5034 if (auto *M0 = dyn_cast<IntrinsicInst>(Op0))
5035 if (M0->getIntrinsicID() == IID &&
5036 (M0->getOperand(0) == Op1 || M0->getOperand(1) == Op1))
5037 return Op0;
5038 if (auto *M1 = dyn_cast<IntrinsicInst>(Op1))
5039 if (M1->getIntrinsicID() == IID &&
5040 (M1->getOperand(0) == Op0 || M1->getOperand(1) == Op0))
5041 return Op1;
5042
Thomas Livelyc3392502018-10-19 19:01:26 +00005043 // min(X, -Inf) --> -Inf (and commuted variant)
5044 // max(X, +Inf) --> +Inf (and commuted variant)
5045 bool UseNegInf = IID == Intrinsic::minnum || IID == Intrinsic::minimum;
Sanjay Patelc6944f72018-08-09 22:20:44 +00005046 const APFloat *C;
5047 if ((match(Op0, m_APFloat(C)) && C->isInfinity() &&
5048 C->isNegative() == UseNegInf) ||
5049 (match(Op1, m_APFloat(C)) && C->isInfinity() &&
5050 C->isNegative() == UseNegInf))
5051 return ConstantFP::getInfinity(ReturnType, UseNegInf);
5052
5053 // TODO: minnum(nnan x, inf) -> x
5054 // TODO: minnum(nnan ninf x, flt_max) -> x
5055 // TODO: maxnum(nnan x, -inf) -> x
5056 // TODO: maxnum(nnan ninf x, -flt_max) -> x
Sanjay Patelf52eeb12018-07-29 14:42:08 +00005057 break;
Sanjay Patelc6944f72018-08-09 22:20:44 +00005058 }
Sanjay Patelf52eeb12018-07-29 14:42:08 +00005059 default:
5060 break;
Matt Arsenault82606662017-01-11 00:57:54 +00005061 }
5062
Sanjay Patelf52eeb12018-07-29 14:42:08 +00005063 return nullptr;
5064}
5065
Tim Northover030bb3d2019-07-11 13:11:44 +00005066static Value *simplifyIntrinsic(CallBase *Call, const SimplifyQuery &Q) {
5067
Sanjay Patelf52eeb12018-07-29 14:42:08 +00005068 // Intrinsics with no operands have some kind of side effect. Don't simplify.
Tim Northover030bb3d2019-07-11 13:11:44 +00005069 unsigned NumOperands = Call->getNumArgOperands();
5070 if (!NumOperands)
Sanjay Patelf52eeb12018-07-29 14:42:08 +00005071 return nullptr;
5072
Tim Northover030bb3d2019-07-11 13:11:44 +00005073 Function *F = cast<Function>(Call->getCalledFunction());
Sanjay Patelf52eeb12018-07-29 14:42:08 +00005074 Intrinsic::ID IID = F->getIntrinsicID();
5075 if (NumOperands == 1)
Tim Northover030bb3d2019-07-11 13:11:44 +00005076 return simplifyUnaryIntrinsic(F, Call->getArgOperand(0), Q);
Sanjay Patelf52eeb12018-07-29 14:42:08 +00005077
5078 if (NumOperands == 2)
Tim Northover030bb3d2019-07-11 13:11:44 +00005079 return simplifyBinaryIntrinsic(F, Call->getArgOperand(0),
5080 Call->getArgOperand(1), Q);
Sanjay Patelf52eeb12018-07-29 14:42:08 +00005081
5082 // Handle intrinsics with 3 or more arguments.
Matt Arsenault82606662017-01-11 00:57:54 +00005083 switch (IID) {
Philip Reamesd8d9b7b2019-04-22 19:30:01 +00005084 case Intrinsic::masked_load:
5085 case Intrinsic::masked_gather: {
Tim Northover030bb3d2019-07-11 13:11:44 +00005086 Value *MaskArg = Call->getArgOperand(2);
5087 Value *PassthruArg = Call->getArgOperand(3);
Matt Arsenault82606662017-01-11 00:57:54 +00005088 // If the mask is all zeros or undef, the "passthru" argument is the result.
5089 if (maskIsAllZeroOrUndef(MaskArg))
5090 return PassthruArg;
5091 return nullptr;
5092 }
Sanjay Patel54421ce2018-07-29 16:36:38 +00005093 case Intrinsic::fshl:
5094 case Intrinsic::fshr: {
Tim Northover030bb3d2019-07-11 13:11:44 +00005095 Value *Op0 = Call->getArgOperand(0), *Op1 = Call->getArgOperand(1),
5096 *ShAmtArg = Call->getArgOperand(2);
Sanjay Patel14ab9172018-11-20 17:34:59 +00005097
5098 // If both operands are undef, the result is undef.
5099 if (match(Op0, m_Undef()) && match(Op1, m_Undef()))
5100 return UndefValue::get(F->getReturnType());
5101
5102 // If shift amount is undef, assume it is zero.
5103 if (match(ShAmtArg, m_Undef()))
Tim Northover030bb3d2019-07-11 13:11:44 +00005104 return Call->getArgOperand(IID == Intrinsic::fshl ? 0 : 1);
Sanjay Patel14ab9172018-11-20 17:34:59 +00005105
Sanjay Patel54421ce2018-07-29 16:36:38 +00005106 const APInt *ShAmtC;
5107 if (match(ShAmtArg, m_APInt(ShAmtC))) {
5108 // If there's effectively no shift, return the 1st arg or 2nd arg.
Sanjay Patel54421ce2018-07-29 16:36:38 +00005109 APInt BitWidth = APInt(ShAmtC->getBitWidth(), ShAmtC->getBitWidth());
5110 if (ShAmtC->urem(BitWidth).isNullValue())
Tim Northover030bb3d2019-07-11 13:11:44 +00005111 return Call->getArgOperand(IID == Intrinsic::fshl ? 0 : 1);
Sanjay Patel54421ce2018-07-29 16:36:38 +00005112 }
5113 return nullptr;
5114 }
Matt Arsenault82606662017-01-11 00:57:54 +00005115 default:
5116 return nullptr;
5117 }
Michael Ilseman54857292013-02-07 19:26:05 +00005118}
5119
Tim Northover030bb3d2019-07-11 13:11:44 +00005120Value *llvm::SimplifyCall(CallBase *Call, const SimplifyQuery &Q) {
5121 Value *Callee = Call->getCalledValue();
Chandler Carruth9dc35582012-12-28 11:30:55 +00005122
Dan Gohman85977e62011-11-04 18:32:42 +00005123 // call undef -> undef
David Majnemerbb53d232016-06-25 07:37:30 +00005124 // call null -> undef
Tim Northover030bb3d2019-07-11 13:11:44 +00005125 if (isa<UndefValue>(Callee) || isa<ConstantPointerNull>(Callee))
5126 return UndefValue::get(Call->getType());
Dan Gohman85977e62011-11-04 18:32:42 +00005127
Tim Northover030bb3d2019-07-11 13:11:44 +00005128 Function *F = dyn_cast<Function>(Callee);
Chandler Carruthf6182152012-12-28 14:23:29 +00005129 if (!F)
Craig Topper9f008862014-04-15 04:59:12 +00005130 return nullptr;
Chandler Carruthf6182152012-12-28 14:23:29 +00005131
David Majnemer15032582015-05-22 03:56:46 +00005132 if (F->isIntrinsic())
Tim Northover030bb3d2019-07-11 13:11:44 +00005133 if (Value *Ret = simplifyIntrinsic(Call, Q))
Michael Ilseman54857292013-02-07 19:26:05 +00005134 return Ret;
5135
Chandler Carruthdac20a82019-02-11 07:54:10 +00005136 if (!canConstantFoldCallTo(Call, F))
Craig Topper9f008862014-04-15 04:59:12 +00005137 return nullptr;
Chandler Carruthf6182152012-12-28 14:23:29 +00005138
5139 SmallVector<Constant *, 4> ConstantArgs;
Tim Northover030bb3d2019-07-11 13:11:44 +00005140 unsigned NumArgs = Call->getNumArgOperands();
5141 ConstantArgs.reserve(NumArgs);
5142 for (auto &Arg : Call->args()) {
5143 Constant *C = dyn_cast<Constant>(&Arg);
Chandler Carruthf6182152012-12-28 14:23:29 +00005144 if (!C)
Craig Topper9f008862014-04-15 04:59:12 +00005145 return nullptr;
Chandler Carruthf6182152012-12-28 14:23:29 +00005146 ConstantArgs.push_back(C);
5147 }
5148
Chandler Carruthdac20a82019-02-11 07:54:10 +00005149 return ConstantFoldCall(Call, F, ConstantArgs, Q.TLI);
Dan Gohman85977e62011-11-04 18:32:42 +00005150}
5151
Sanjay Patel472cc782016-01-11 22:14:42 +00005152/// See if we can compute a simplified version of this instruction.
5153/// If not, this returns null.
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005154
Daniel Berlin4d0fe642017-04-28 19:55:38 +00005155Value *llvm::SimplifyInstruction(Instruction *I, const SimplifyQuery &SQ,
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005156 OptimizationRemarkEmitter *ORE) {
Daniel Berlin4d0fe642017-04-28 19:55:38 +00005157 const SimplifyQuery Q = SQ.CxtI ? SQ : SQ.getWithInstruction(I);
Duncan Sands64e41cf2010-11-17 08:35:29 +00005158 Value *Result;
5159
Chris Lattnerfb7f87d2009-11-10 01:08:51 +00005160 switch (I->getOpcode()) {
5161 default:
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005162 Result = ConstantFoldInstruction(I, Q.DL, Q.TLI);
Duncan Sands64e41cf2010-11-17 08:35:29 +00005163 break;
Cameron McInallyc3167692019-05-06 16:05:10 +00005164 case Instruction::FNeg:
5165 Result = SimplifyFNegInst(I->getOperand(0), I->getFastMathFlags(), Q);
5166 break;
Michael Ilsemanbb6f6912012-12-12 00:27:46 +00005167 case Instruction::FAdd:
5168 Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005169 I->getFastMathFlags(), Q);
Michael Ilsemanbb6f6912012-12-12 00:27:46 +00005170 break;
Chris Lattner3d9823b2009-11-27 17:42:22 +00005171 case Instruction::Add:
Florian Hahn19f9e322018-08-17 14:39:04 +00005172 Result =
5173 SimplifyAddInst(I->getOperand(0), I->getOperand(1),
5174 Q.IIQ.hasNoSignedWrap(cast<BinaryOperator>(I)),
5175 Q.IIQ.hasNoUnsignedWrap(cast<BinaryOperator>(I)), Q);
Duncan Sands64e41cf2010-11-17 08:35:29 +00005176 break;
Michael Ilsemanbb6f6912012-12-12 00:27:46 +00005177 case Instruction::FSub:
5178 Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005179 I->getFastMathFlags(), Q);
Michael Ilsemanbb6f6912012-12-12 00:27:46 +00005180 break;
Duncan Sands0a2c41682010-12-15 14:07:39 +00005181 case Instruction::Sub:
Florian Hahn19f9e322018-08-17 14:39:04 +00005182 Result =
5183 SimplifySubInst(I->getOperand(0), I->getOperand(1),
5184 Q.IIQ.hasNoSignedWrap(cast<BinaryOperator>(I)),
5185 Q.IIQ.hasNoUnsignedWrap(cast<BinaryOperator>(I)), Q);
Duncan Sands0a2c41682010-12-15 14:07:39 +00005186 break;
Michael Ilsemanbe9137a2012-11-27 00:46:26 +00005187 case Instruction::FMul:
5188 Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005189 I->getFastMathFlags(), Q);
Michael Ilsemanbe9137a2012-11-27 00:46:26 +00005190 break;
Duncan Sandsd0eb6d32010-12-21 14:00:22 +00005191 case Instruction::Mul:
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005192 Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), Q);
Duncan Sandsd0eb6d32010-12-21 14:00:22 +00005193 break;
Duncan Sands771e82a2011-01-28 16:51:11 +00005194 case Instruction::SDiv:
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005195 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), Q);
Duncan Sands771e82a2011-01-28 16:51:11 +00005196 break;
5197 case Instruction::UDiv:
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005198 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), Q);
Duncan Sands771e82a2011-01-28 16:51:11 +00005199 break;
Frits van Bommelc2549662011-01-29 15:26:31 +00005200 case Instruction::FDiv:
Mehdi Aminicd3ca6f2015-02-23 18:30:25 +00005201 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1),
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005202 I->getFastMathFlags(), Q);
Frits van Bommelc2549662011-01-29 15:26:31 +00005203 break;
Duncan Sandsa3e36992011-05-02 16:27:02 +00005204 case Instruction::SRem:
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005205 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), Q);
Duncan Sandsa3e36992011-05-02 16:27:02 +00005206 break;
5207 case Instruction::URem:
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005208 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), Q);
Duncan Sandsa3e36992011-05-02 16:27:02 +00005209 break;
5210 case Instruction::FRem:
Mehdi Aminicd3ca6f2015-02-23 18:30:25 +00005211 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1),
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005212 I->getFastMathFlags(), Q);
Duncan Sandsa3e36992011-05-02 16:27:02 +00005213 break;
Duncan Sands7f60dc12011-01-14 00:37:45 +00005214 case Instruction::Shl:
Florian Hahn19f9e322018-08-17 14:39:04 +00005215 Result =
5216 SimplifyShlInst(I->getOperand(0), I->getOperand(1),
5217 Q.IIQ.hasNoSignedWrap(cast<BinaryOperator>(I)),
5218 Q.IIQ.hasNoUnsignedWrap(cast<BinaryOperator>(I)), Q);
Duncan Sands7f60dc12011-01-14 00:37:45 +00005219 break;
5220 case Instruction::LShr:
Chris Lattner9e4aa022011-02-09 17:15:04 +00005221 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
Florian Hahn19f9e322018-08-17 14:39:04 +00005222 Q.IIQ.isExact(cast<BinaryOperator>(I)), Q);
Duncan Sands7f60dc12011-01-14 00:37:45 +00005223 break;
5224 case Instruction::AShr:
Chris Lattner9e4aa022011-02-09 17:15:04 +00005225 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
Florian Hahn19f9e322018-08-17 14:39:04 +00005226 Q.IIQ.isExact(cast<BinaryOperator>(I)), Q);
Duncan Sands7f60dc12011-01-14 00:37:45 +00005227 break;
Chris Lattnerfb7f87d2009-11-10 01:08:51 +00005228 case Instruction::And:
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005229 Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), Q);
Duncan Sands64e41cf2010-11-17 08:35:29 +00005230 break;
Chris Lattnerfb7f87d2009-11-10 01:08:51 +00005231 case Instruction::Or:
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005232 Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), Q);
Duncan Sands64e41cf2010-11-17 08:35:29 +00005233 break;
Duncan Sandsc89ac072010-11-17 18:52:15 +00005234 case Instruction::Xor:
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005235 Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), Q);
Duncan Sandsc89ac072010-11-17 18:52:15 +00005236 break;
Chris Lattnerfb7f87d2009-11-10 01:08:51 +00005237 case Instruction::ICmp:
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005238 Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
5239 I->getOperand(0), I->getOperand(1), Q);
Duncan Sands64e41cf2010-11-17 08:35:29 +00005240 break;
Chris Lattnerfb7f87d2009-11-10 01:08:51 +00005241 case Instruction::FCmp:
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005242 Result =
5243 SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(), I->getOperand(0),
5244 I->getOperand(1), I->getFastMathFlags(), Q);
Duncan Sands64e41cf2010-11-17 08:35:29 +00005245 break;
Chris Lattnerc707fa92010-04-20 05:32:14 +00005246 case Instruction::Select:
Duncan Sands64e41cf2010-11-17 08:35:29 +00005247 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005248 I->getOperand(2), Q);
Duncan Sands64e41cf2010-11-17 08:35:29 +00005249 break;
Chris Lattner8574aba2009-11-27 00:29:05 +00005250 case Instruction::GetElementPtr: {
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005251 SmallVector<Value *, 8> Ops(I->op_begin(), I->op_end());
Manuel Jacob20c6d5b2016-01-17 22:46:43 +00005252 Result = SimplifyGEPInst(cast<GetElementPtrInst>(I)->getSourceElementType(),
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005253 Ops, Q);
Duncan Sands64e41cf2010-11-17 08:35:29 +00005254 break;
Chris Lattner8574aba2009-11-27 00:29:05 +00005255 }
Duncan Sandsfd26a952011-09-05 06:52:48 +00005256 case Instruction::InsertValue: {
5257 InsertValueInst *IV = cast<InsertValueInst>(I);
5258 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
5259 IV->getInsertedValueOperand(),
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005260 IV->getIndices(), Q);
Duncan Sandsfd26a952011-09-05 06:52:48 +00005261 break;
5262 }
Igor Laevskye0edb662017-12-13 11:21:18 +00005263 case Instruction::InsertElement: {
5264 auto *IE = cast<InsertElementInst>(I);
5265 Result = SimplifyInsertElementInst(IE->getOperand(0), IE->getOperand(1),
5266 IE->getOperand(2), Q);
5267 break;
5268 }
David Majnemer25a796e2015-07-13 01:15:46 +00005269 case Instruction::ExtractValue: {
5270 auto *EVI = cast<ExtractValueInst>(I);
5271 Result = SimplifyExtractValueInst(EVI->getAggregateOperand(),
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005272 EVI->getIndices(), Q);
David Majnemer25a796e2015-07-13 01:15:46 +00005273 break;
5274 }
David Majnemer599ca442015-07-13 01:15:53 +00005275 case Instruction::ExtractElement: {
5276 auto *EEI = cast<ExtractElementInst>(I);
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005277 Result = SimplifyExtractElementInst(EEI->getVectorOperand(),
5278 EEI->getIndexOperand(), Q);
David Majnemer599ca442015-07-13 01:15:53 +00005279 break;
5280 }
Zvi Rackover8f460652017-04-03 22:05:30 +00005281 case Instruction::ShuffleVector: {
5282 auto *SVI = cast<ShuffleVectorInst>(I);
5283 Result = SimplifyShuffleVectorInst(SVI->getOperand(0), SVI->getOperand(1),
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005284 SVI->getMask(), SVI->getType(), Q);
Zvi Rackover8f460652017-04-03 22:05:30 +00005285 break;
5286 }
Duncan Sands4581ddc2010-11-14 13:30:18 +00005287 case Instruction::PHI:
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005288 Result = SimplifyPHINode(cast<PHINode>(I), Q);
Duncan Sands64e41cf2010-11-17 08:35:29 +00005289 break;
Chandler Carruth9dc35582012-12-28 11:30:55 +00005290 case Instruction::Call: {
Chandler Carruthdac20a82019-02-11 07:54:10 +00005291 Result = SimplifyCall(cast<CallInst>(I), Q);
Dan Gohman85977e62011-11-04 18:32:42 +00005292 break;
Chandler Carruth9dc35582012-12-28 11:30:55 +00005293 }
David Majnemer6774d612016-07-26 17:58:05 +00005294#define HANDLE_CAST_INST(num, opc, clas) case Instruction::opc:
5295#include "llvm/IR/Instruction.def"
5296#undef HANDLE_CAST_INST
Daniel Berlin5e3fcb12017-04-26 04:09:56 +00005297 Result =
5298 SimplifyCastInst(I->getOpcode(), I->getOperand(0), I->getType(), Q);
David Majnemera90a6212016-07-26 05:52:29 +00005299 break;
Craig Topper81c03a72017-04-12 22:54:24 +00005300 case Instruction::Alloca:
5301 // No simplifications for Alloca and it can't be constant folded.
5302 Result = nullptr;
5303 break;
Chris Lattnerfb7f87d2009-11-10 01:08:51 +00005304 }
Duncan Sands64e41cf2010-11-17 08:35:29 +00005305
Hal Finkelf2199b22015-10-23 20:37:08 +00005306 // In general, it is possible for computeKnownBits to determine all bits in a
5307 // value even when the operands are not all constants.
Sanjay Patel8ca30ab2016-11-27 21:07:28 +00005308 if (!Result && I->getType()->isIntOrIntVectorTy()) {
Craig Topper8205a1a2017-05-24 16:53:07 +00005309 KnownBits Known = computeKnownBits(I, Q.DL, /*Depth*/ 0, Q.AC, I, Q.DT, ORE);
Craig Topper8189a872017-05-03 23:12:29 +00005310 if (Known.isConstant())
5311 Result = ConstantInt::get(I->getType(), Known.getConstant());
Hal Finkelf2199b22015-10-23 20:37:08 +00005312 }
5313
Duncan Sands64e41cf2010-11-17 08:35:29 +00005314 /// If called on unreachable code, the above logic may report that the
5315 /// instruction simplified to itself. Make life easier for users by
Duncan Sands019a4182010-12-15 11:02:22 +00005316 /// detecting that case here, returning a safe value instead.
5317 return Result == I ? UndefValue::get(I->getType()) : Result;
Chris Lattnerfb7f87d2009-11-10 01:08:51 +00005318}
5319
Adrian Prantl5f8f34e42018-05-01 15:54:18 +00005320/// Implementation of recursive simplification through an instruction's
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005321/// uses.
Chris Lattner852d6d62009-11-10 22:26:15 +00005322///
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005323/// This is the common implementation of the recursive simplification routines.
5324/// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
5325/// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
5326/// instructions to process and attempt to simplify it using
Joerg Sonnenberger799c9662019-08-29 13:22:30 +00005327/// InstructionSimplify. Recursively visited users which could not be
5328/// simplified themselves are to the optional UnsimplifiedUsers set for
5329/// further processing by the caller.
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005330///
5331/// This routine returns 'true' only when *it* simplifies something. The passed
5332/// in simplified value does not count toward this.
Joerg Sonnenberger799c9662019-08-29 13:22:30 +00005333static bool replaceAndRecursivelySimplifyImpl(
5334 Instruction *I, Value *SimpleV, const TargetLibraryInfo *TLI,
5335 const DominatorTree *DT, AssumptionCache *AC,
5336 SmallSetVector<Instruction *, 8> *UnsimplifiedUsers = nullptr) {
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005337 bool Simplified = false;
Chandler Carruth77e8bfb2012-03-24 22:34:26 +00005338 SmallSetVector<Instruction *, 8> Worklist;
Mehdi Aminia28d91d2015-03-10 02:37:25 +00005339 const DataLayout &DL = I->getModule()->getDataLayout();
Duncan Sands7e800d62010-11-14 11:23:23 +00005340
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005341 // If we have an explicit value to collapse to, do that round of the
5342 // simplification loop by hand initially.
5343 if (SimpleV) {
Chandler Carruthcdf47882014-03-09 03:16:01 +00005344 for (User *U : I->users())
5345 if (U != I)
5346 Worklist.insert(cast<Instruction>(U));
Duncan Sands7e800d62010-11-14 11:23:23 +00005347
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005348 // Replace the instruction with its simplified value.
5349 I->replaceAllUsesWith(SimpleV);
Chris Lattner19eff2a2010-07-15 06:36:08 +00005350
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005351 // Gracefully handle edge cases where the instruction is not wired into any
5352 // parent block.
Chandler Carruth9ae926b2018-08-26 09:51:22 +00005353 if (I->getParent() && !I->isEHPad() && !I->isTerminator() &&
David Majnemer909793f2016-08-04 04:24:02 +00005354 !I->mayHaveSideEffects())
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005355 I->eraseFromParent();
5356 } else {
Chandler Carruth77e8bfb2012-03-24 22:34:26 +00005357 Worklist.insert(I);
Chris Lattner852d6d62009-11-10 22:26:15 +00005358 }
Duncan Sands7e800d62010-11-14 11:23:23 +00005359
Chandler Carruth77e8bfb2012-03-24 22:34:26 +00005360 // Note that we must test the size on each iteration, the worklist can grow.
5361 for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
5362 I = Worklist[Idx];
Duncan Sands7e800d62010-11-14 11:23:23 +00005363
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005364 // See if this instruction simplifies.
Daniel Berlin4d0fe642017-04-28 19:55:38 +00005365 SimpleV = SimplifyInstruction(I, {DL, TLI, DT, AC});
Joerg Sonnenberger799c9662019-08-29 13:22:30 +00005366 if (!SimpleV) {
5367 if (UnsimplifiedUsers)
5368 UnsimplifiedUsers->insert(I);
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005369 continue;
Joerg Sonnenberger799c9662019-08-29 13:22:30 +00005370 }
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005371
5372 Simplified = true;
5373
5374 // Stash away all the uses of the old instruction so we can check them for
5375 // recursive simplifications after a RAUW. This is cheaper than checking all
5376 // uses of To on the recursive step in most cases.
Chandler Carruthcdf47882014-03-09 03:16:01 +00005377 for (User *U : I->users())
5378 Worklist.insert(cast<Instruction>(U));
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005379
5380 // Replace the instruction with its simplified value.
5381 I->replaceAllUsesWith(SimpleV);
5382
5383 // Gracefully handle edge cases where the instruction is not wired into any
5384 // parent block.
Chandler Carruth9ae926b2018-08-26 09:51:22 +00005385 if (I->getParent() && !I->isEHPad() && !I->isTerminator() &&
David Majnemer909793f2016-08-04 04:24:02 +00005386 !I->mayHaveSideEffects())
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005387 I->eraseFromParent();
5388 }
5389 return Simplified;
5390}
5391
Mehdi Aminia28d91d2015-03-10 02:37:25 +00005392bool llvm::recursivelySimplifyInstruction(Instruction *I,
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005393 const TargetLibraryInfo *TLI,
Daniel Jasperaec2fa32016-12-19 08:22:17 +00005394 const DominatorTree *DT,
5395 AssumptionCache *AC) {
Joerg Sonnenberger799c9662019-08-29 13:22:30 +00005396 return replaceAndRecursivelySimplifyImpl(I, nullptr, TLI, DT, AC, nullptr);
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005397}
5398
Joerg Sonnenberger799c9662019-08-29 13:22:30 +00005399bool llvm::replaceAndRecursivelySimplify(
5400 Instruction *I, Value *SimpleV, const TargetLibraryInfo *TLI,
5401 const DominatorTree *DT, AssumptionCache *AC,
5402 SmallSetVector<Instruction *, 8> *UnsimplifiedUsers) {
Chandler Carruthcf1b5852012-03-24 21:11:24 +00005403 assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
5404 assert(SimpleV && "Must provide a simplified value.");
Joerg Sonnenberger799c9662019-08-29 13:22:30 +00005405 return replaceAndRecursivelySimplifyImpl(I, SimpleV, TLI, DT, AC,
5406 UnsimplifiedUsers);
Chris Lattner852d6d62009-11-10 22:26:15 +00005407}
Daniel Berlin4d0fe642017-04-28 19:55:38 +00005408
5409namespace llvm {
5410const SimplifyQuery getBestSimplifyQuery(Pass &P, Function &F) {
5411 auto *DTWP = P.getAnalysisIfAvailable<DominatorTreeWrapperPass>();
5412 auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
5413 auto *TLIWP = P.getAnalysisIfAvailable<TargetLibraryInfoWrapperPass>();
Teresa Johnson9c27b592019-09-07 03:09:36 +00005414 auto *TLI = TLIWP ? &TLIWP->getTLI(F) : nullptr;
Daniel Berlin4d0fe642017-04-28 19:55:38 +00005415 auto *ACWP = P.getAnalysisIfAvailable<AssumptionCacheTracker>();
5416 auto *AC = ACWP ? &ACWP->getAssumptionCache(F) : nullptr;
5417 return {F.getParent()->getDataLayout(), TLI, DT, AC};
5418}
5419
5420const SimplifyQuery getBestSimplifyQuery(LoopStandardAnalysisResults &AR,
5421 const DataLayout &DL) {
5422 return {DL, &AR.TLI, &AR.DT, &AR.AC};
5423}
5424
5425template <class T, class... TArgs>
5426const SimplifyQuery getBestSimplifyQuery(AnalysisManager<T, TArgs...> &AM,
5427 Function &F) {
5428 auto *DT = AM.template getCachedResult<DominatorTreeAnalysis>(F);
5429 auto *TLI = AM.template getCachedResult<TargetLibraryAnalysis>(F);
5430 auto *AC = AM.template getCachedResult<AssumptionAnalysis>(F);
5431 return {F.getParent()->getDataLayout(), TLI, DT, AC};
5432}
5433template const SimplifyQuery getBestSimplifyQuery(AnalysisManager<Function> &,
5434 Function &);
5435}