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Owen Anderson5fba6c12007-05-29 21:53:49 +00001//===- GVNPRE.cpp - Eliminate redundant values and expressions ------------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file was developed by the Owen Anderson and is distributed under
6// the University of Illinois Open Source License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This pass performs a hybrid of global value numbering and partial redundancy
11// elimination, known as GVN-PRE. It performs partial redundancy elimination on
12// values, rather than lexical expressions, allowing a more comprehensive view
13// the optimization. It replaces redundant values with uses of earlier
14// occurences of the same value. While this is beneficial in that it eliminates
15// unneeded computation, it also increases register pressure by creating large
Owen Andersonb232efa2007-06-08 20:57:08 +000016// live ranges, and should be used with caution on platforms that are very
Owen Anderson5fba6c12007-05-29 21:53:49 +000017// sensitive to register pressure.
18//
19//===----------------------------------------------------------------------===//
20
21#define DEBUG_TYPE "gvnpre"
22#include "llvm/Value.h"
23#include "llvm/Transforms/Scalar.h"
24#include "llvm/Instructions.h"
25#include "llvm/Function.h"
26#include "llvm/Analysis/Dominators.h"
Owen Anderson28a2d442007-06-22 00:20:30 +000027#include "llvm/ADT/BitVector.h"
Owen Anderson1ad2c102007-06-19 23:23:54 +000028#include "llvm/ADT/DenseMap.h"
Owen Anderson5fba6c12007-05-29 21:53:49 +000029#include "llvm/ADT/DepthFirstIterator.h"
Owen Anderson43ca4b42007-06-25 18:25:31 +000030#include "llvm/ADT/PostOrderIterator.h"
Owen Anderson2ff912b2007-06-21 17:57:53 +000031#include "llvm/ADT/SmallPtrSet.h"
Owen Anderson5fba6c12007-05-29 21:53:49 +000032#include "llvm/ADT/Statistic.h"
Owen Andersonbe802402007-06-08 01:03:01 +000033#include "llvm/Support/CFG.h"
Owen Anderson5fba6c12007-05-29 21:53:49 +000034#include "llvm/Support/Compiler.h"
Owen Anderson4a6ec8f2007-05-29 23:15:21 +000035#include "llvm/Support/Debug.h"
Owen Anderson5fba6c12007-05-29 21:53:49 +000036#include <algorithm>
Owen Anderson331bf6a2007-05-31 22:44:11 +000037#include <deque>
Owen Anderson5fba6c12007-05-29 21:53:49 +000038#include <map>
Owen Anderson331bf6a2007-05-31 22:44:11 +000039#include <vector>
Owen Anderson5fba6c12007-05-29 21:53:49 +000040#include <set>
Owen Anderson5fba6c12007-05-29 21:53:49 +000041using namespace llvm;
42
Owen Andersonb56fba02007-06-19 03:31:41 +000043//===----------------------------------------------------------------------===//
44// ValueTable Class
45//===----------------------------------------------------------------------===//
46
Owen Andersonfd5683a2007-06-21 00:19:05 +000047/// This class holds the mapping between values and value numbers. It is used
48/// as an efficient mechanism to determine the expression-wise equivalence of
49/// two values.
Owen Andersonb56fba02007-06-19 03:31:41 +000050
51namespace {
52 class VISIBILITY_HIDDEN ValueTable {
53 public:
54 struct Expression {
55 enum ExpressionOpcode { ADD, SUB, MUL, UDIV, SDIV, FDIV, UREM, SREM,
56 FREM, SHL, LSHR, ASHR, AND, OR, XOR, ICMPEQ,
57 ICMPNE, ICMPUGT, ICMPUGE, ICMPULT, ICMPULE,
58 ICMPSGT, ICMPSGE, ICMPSLT, ICMPSLE, FCMPOEQ,
59 FCMPOGT, FCMPOGE, FCMPOLT, FCMPOLE, FCMPONE,
60 FCMPORD, FCMPUNO, FCMPUEQ, FCMPUGT, FCMPUGE,
Owen Andersonb6a39fc2007-06-27 04:10:46 +000061 FCMPULT, FCMPULE, FCMPUNE, EXTRACT, INSERT,
Owen Anderson8a9fa5d2007-06-28 23:51:21 +000062 SHUFFLE, SELECT };
Owen Andersonb56fba02007-06-19 03:31:41 +000063
64 ExpressionOpcode opcode;
Owen Andersonb6a39fc2007-06-27 04:10:46 +000065 uint32_t firstVN;
66 uint32_t secondVN;
67 uint32_t thirdVN;
Owen Andersonb56fba02007-06-19 03:31:41 +000068
69 bool operator< (const Expression& other) const {
70 if (opcode < other.opcode)
71 return true;
72 else if (opcode > other.opcode)
73 return false;
Owen Andersonb6a39fc2007-06-27 04:10:46 +000074 else if (firstVN < other.firstVN)
Owen Andersonb56fba02007-06-19 03:31:41 +000075 return true;
Owen Andersonb6a39fc2007-06-27 04:10:46 +000076 else if (firstVN > other.firstVN)
Owen Andersonb56fba02007-06-19 03:31:41 +000077 return false;
Owen Andersonb6a39fc2007-06-27 04:10:46 +000078 else if (secondVN < other.secondVN)
Owen Andersonb56fba02007-06-19 03:31:41 +000079 return true;
Owen Andersonb6a39fc2007-06-27 04:10:46 +000080 else if (secondVN > other.secondVN)
81 return false;
82 else if (thirdVN < other.thirdVN)
83 return true;
84 else if (thirdVN > other.thirdVN)
Owen Andersonb56fba02007-06-19 03:31:41 +000085 return false;
86 else
87 return false;
Owen Andersona75dd4d2007-06-12 00:50:47 +000088 }
Owen Andersonb56fba02007-06-19 03:31:41 +000089 };
90
91 private:
Owen Anderson1ad2c102007-06-19 23:23:54 +000092 DenseMap<Value*, uint32_t> valueNumbering;
Owen Andersonb56fba02007-06-19 03:31:41 +000093 std::map<Expression, uint32_t> expressionNumbering;
94
Owen Andersonb56fba02007-06-19 03:31:41 +000095 uint32_t nextValueNumber;
96
97 Expression::ExpressionOpcode getOpcode(BinaryOperator* BO);
98 Expression::ExpressionOpcode getOpcode(CmpInst* C);
Owen Andersonfd5683a2007-06-21 00:19:05 +000099 Expression create_expression(BinaryOperator* BO);
100 Expression create_expression(CmpInst* C);
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000101 Expression create_expression(ShuffleVectorInst* V);
102 Expression create_expression(ExtractElementInst* C);
103 Expression create_expression(InsertElementInst* V);
Owen Anderson8a9fa5d2007-06-28 23:51:21 +0000104 Expression create_expression(SelectInst* V);
Owen Andersonb56fba02007-06-19 03:31:41 +0000105 public:
106 ValueTable() { nextValueNumber = 1; }
107 uint32_t lookup_or_add(Value* V);
Owen Anderson8a9fa5d2007-06-28 23:51:21 +0000108 uint32_t lookup(Value* V) const;
Owen Andersonb56fba02007-06-19 03:31:41 +0000109 void add(Value* V, uint32_t num);
110 void clear();
Owen Anderson91c54952007-06-19 05:37:32 +0000111 void erase(Value* v);
Owen Anderson28a2d442007-06-22 00:20:30 +0000112 unsigned size();
Owen Andersonb56fba02007-06-19 03:31:41 +0000113 };
114}
115
Owen Andersonfd5683a2007-06-21 00:19:05 +0000116//===----------------------------------------------------------------------===//
117// ValueTable Internal Functions
118//===----------------------------------------------------------------------===//
Owen Andersonb56fba02007-06-19 03:31:41 +0000119ValueTable::Expression::ExpressionOpcode
Owen Andersonfd5683a2007-06-21 00:19:05 +0000120 ValueTable::getOpcode(BinaryOperator* BO) {
Owen Andersonb56fba02007-06-19 03:31:41 +0000121 switch(BO->getOpcode()) {
122 case Instruction::Add:
123 return Expression::ADD;
124 case Instruction::Sub:
125 return Expression::SUB;
126 case Instruction::Mul:
127 return Expression::MUL;
128 case Instruction::UDiv:
129 return Expression::UDIV;
130 case Instruction::SDiv:
131 return Expression::SDIV;
132 case Instruction::FDiv:
133 return Expression::FDIV;
134 case Instruction::URem:
135 return Expression::UREM;
136 case Instruction::SRem:
137 return Expression::SREM;
138 case Instruction::FRem:
139 return Expression::FREM;
140 case Instruction::Shl:
141 return Expression::SHL;
142 case Instruction::LShr:
143 return Expression::LSHR;
144 case Instruction::AShr:
145 return Expression::ASHR;
146 case Instruction::And:
147 return Expression::AND;
148 case Instruction::Or:
149 return Expression::OR;
150 case Instruction::Xor:
151 return Expression::XOR;
152
153 // THIS SHOULD NEVER HAPPEN
154 default:
155 assert(0 && "Binary operator with unknown opcode?");
156 return Expression::ADD;
157 }
158}
159
160ValueTable::Expression::ExpressionOpcode ValueTable::getOpcode(CmpInst* C) {
161 if (C->getOpcode() == Instruction::ICmp) {
162 switch (C->getPredicate()) {
163 case ICmpInst::ICMP_EQ:
164 return Expression::ICMPEQ;
165 case ICmpInst::ICMP_NE:
166 return Expression::ICMPNE;
167 case ICmpInst::ICMP_UGT:
168 return Expression::ICMPUGT;
169 case ICmpInst::ICMP_UGE:
170 return Expression::ICMPUGE;
171 case ICmpInst::ICMP_ULT:
172 return Expression::ICMPULT;
173 case ICmpInst::ICMP_ULE:
174 return Expression::ICMPULE;
175 case ICmpInst::ICMP_SGT:
176 return Expression::ICMPSGT;
177 case ICmpInst::ICMP_SGE:
178 return Expression::ICMPSGE;
179 case ICmpInst::ICMP_SLT:
180 return Expression::ICMPSLT;
181 case ICmpInst::ICMP_SLE:
182 return Expression::ICMPSLE;
183
184 // THIS SHOULD NEVER HAPPEN
185 default:
186 assert(0 && "Comparison with unknown predicate?");
187 return Expression::ICMPEQ;
188 }
189 } else {
190 switch (C->getPredicate()) {
191 case FCmpInst::FCMP_OEQ:
192 return Expression::FCMPOEQ;
193 case FCmpInst::FCMP_OGT:
194 return Expression::FCMPOGT;
195 case FCmpInst::FCMP_OGE:
196 return Expression::FCMPOGE;
197 case FCmpInst::FCMP_OLT:
198 return Expression::FCMPOLT;
199 case FCmpInst::FCMP_OLE:
200 return Expression::FCMPOLE;
201 case FCmpInst::FCMP_ONE:
202 return Expression::FCMPONE;
203 case FCmpInst::FCMP_ORD:
204 return Expression::FCMPORD;
205 case FCmpInst::FCMP_UNO:
206 return Expression::FCMPUNO;
207 case FCmpInst::FCMP_UEQ:
208 return Expression::FCMPUEQ;
209 case FCmpInst::FCMP_UGT:
210 return Expression::FCMPUGT;
211 case FCmpInst::FCMP_UGE:
212 return Expression::FCMPUGE;
213 case FCmpInst::FCMP_ULT:
214 return Expression::FCMPULT;
215 case FCmpInst::FCMP_ULE:
216 return Expression::FCMPULE;
217 case FCmpInst::FCMP_UNE:
218 return Expression::FCMPUNE;
219
220 // THIS SHOULD NEVER HAPPEN
221 default:
222 assert(0 && "Comparison with unknown predicate?");
223 return Expression::FCMPOEQ;
Owen Anderson223718c2007-06-09 18:35:31 +0000224 }
225 }
Owen Andersonb56fba02007-06-19 03:31:41 +0000226}
227
Owen Andersonfd5683a2007-06-21 00:19:05 +0000228ValueTable::Expression ValueTable::create_expression(BinaryOperator* BO) {
229 Expression e;
230
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000231 e.firstVN = lookup_or_add(BO->getOperand(0));
232 e.secondVN = lookup_or_add(BO->getOperand(1));
233 e.thirdVN = 0;
Owen Andersonfd5683a2007-06-21 00:19:05 +0000234 e.opcode = getOpcode(BO);
235
Owen Andersonfd5683a2007-06-21 00:19:05 +0000236 return e;
237}
238
239ValueTable::Expression ValueTable::create_expression(CmpInst* C) {
240 Expression e;
241
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000242 e.firstVN = lookup_or_add(C->getOperand(0));
243 e.secondVN = lookup_or_add(C->getOperand(1));
244 e.thirdVN = 0;
Owen Andersonfd5683a2007-06-21 00:19:05 +0000245 e.opcode = getOpcode(C);
246
Owen Andersonfd5683a2007-06-21 00:19:05 +0000247 return e;
248}
249
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000250ValueTable::Expression ValueTable::create_expression(ShuffleVectorInst* S) {
251 Expression e;
252
253 e.firstVN = lookup_or_add(S->getOperand(0));
254 e.secondVN = lookup_or_add(S->getOperand(1));
255 e.thirdVN = lookup_or_add(S->getOperand(2));
256 e.opcode = Expression::SHUFFLE;
257
258 return e;
259}
260
261ValueTable::Expression ValueTable::create_expression(ExtractElementInst* E) {
262 Expression e;
263
264 e.firstVN = lookup_or_add(E->getOperand(0));
265 e.secondVN = lookup_or_add(E->getOperand(1));
266 e.thirdVN = 0;
267 e.opcode = Expression::EXTRACT;
268
269 return e;
270}
271
272ValueTable::Expression ValueTable::create_expression(InsertElementInst* I) {
273 Expression e;
274
275 e.firstVN = lookup_or_add(I->getOperand(0));
276 e.secondVN = lookup_or_add(I->getOperand(1));
277 e.thirdVN = lookup_or_add(I->getOperand(2));
278 e.opcode = Expression::INSERT;
279
280 return e;
281}
282
Owen Anderson8a9fa5d2007-06-28 23:51:21 +0000283ValueTable::Expression ValueTable::create_expression(SelectInst* I) {
284 Expression e;
285
286 e.firstVN = lookup_or_add(I->getCondition());
287 e.secondVN = lookup_or_add(I->getTrueValue());
288 e.thirdVN = lookup_or_add(I->getFalseValue());
289 e.opcode = Expression::SELECT;
290
291 return e;
292}
293
Owen Andersonfd5683a2007-06-21 00:19:05 +0000294//===----------------------------------------------------------------------===//
295// ValueTable External Functions
296//===----------------------------------------------------------------------===//
297
298/// lookup_or_add - Returns the value number for the specified value, assigning
299/// it a new number if it did not have one before.
Owen Andersonb56fba02007-06-19 03:31:41 +0000300uint32_t ValueTable::lookup_or_add(Value* V) {
Owen Anderson1ad2c102007-06-19 23:23:54 +0000301 DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
Owen Andersonb56fba02007-06-19 03:31:41 +0000302 if (VI != valueNumbering.end())
303 return VI->second;
Owen Anderson223718c2007-06-09 18:35:31 +0000304
Owen Anderson223718c2007-06-09 18:35:31 +0000305
Owen Andersonb56fba02007-06-19 03:31:41 +0000306 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(V)) {
307 Expression e = create_expression(BO);
308
309 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
310 if (EI != expressionNumbering.end()) {
311 valueNumbering.insert(std::make_pair(V, EI->second));
312 return EI->second;
313 } else {
314 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
315 valueNumbering.insert(std::make_pair(V, nextValueNumber));
316
317 return nextValueNumber++;
318 }
319 } else if (CmpInst* C = dyn_cast<CmpInst>(V)) {
320 Expression e = create_expression(C);
321
322 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
323 if (EI != expressionNumbering.end()) {
324 valueNumbering.insert(std::make_pair(V, EI->second));
325 return EI->second;
326 } else {
327 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
328 valueNumbering.insert(std::make_pair(V, nextValueNumber));
329
330 return nextValueNumber++;
331 }
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000332 } else if (ShuffleVectorInst* U = dyn_cast<ShuffleVectorInst>(V)) {
333 Expression e = create_expression(U);
334
335 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
336 if (EI != expressionNumbering.end()) {
337 valueNumbering.insert(std::make_pair(V, EI->second));
338 return EI->second;
339 } else {
340 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
341 valueNumbering.insert(std::make_pair(V, nextValueNumber));
342
343 return nextValueNumber++;
344 }
345 } else if (ExtractElementInst* U = dyn_cast<ExtractElementInst>(V)) {
346 Expression e = create_expression(U);
347
348 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
349 if (EI != expressionNumbering.end()) {
350 valueNumbering.insert(std::make_pair(V, EI->second));
351 return EI->second;
352 } else {
353 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
354 valueNumbering.insert(std::make_pair(V, nextValueNumber));
355
356 return nextValueNumber++;
357 }
358 } else if (InsertElementInst* U = dyn_cast<InsertElementInst>(V)) {
359 Expression e = create_expression(U);
360
361 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
362 if (EI != expressionNumbering.end()) {
363 valueNumbering.insert(std::make_pair(V, EI->second));
364 return EI->second;
365 } else {
366 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
367 valueNumbering.insert(std::make_pair(V, nextValueNumber));
368
369 return nextValueNumber++;
370 }
Owen Anderson8a9fa5d2007-06-28 23:51:21 +0000371 } else if (SelectInst* U = dyn_cast<SelectInst>(V)) {
372 Expression e = create_expression(U);
373
374 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
375 if (EI != expressionNumbering.end()) {
376 valueNumbering.insert(std::make_pair(V, EI->second));
377 return EI->second;
378 } else {
379 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
380 valueNumbering.insert(std::make_pair(V, nextValueNumber));
381
382 return nextValueNumber++;
383 }
Owen Andersonb56fba02007-06-19 03:31:41 +0000384 } else {
385 valueNumbering.insert(std::make_pair(V, nextValueNumber));
386 return nextValueNumber++;
Owen Anderson0b68cda2007-06-03 05:55:58 +0000387 }
Owen Andersonb56fba02007-06-19 03:31:41 +0000388}
389
Owen Andersonfd5683a2007-06-21 00:19:05 +0000390/// lookup - Returns the value number of the specified value. Fails if
391/// the value has not yet been numbered.
Owen Anderson8a9fa5d2007-06-28 23:51:21 +0000392uint32_t ValueTable::lookup(Value* V) const {
Owen Anderson1ad2c102007-06-19 23:23:54 +0000393 DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
Owen Andersonb56fba02007-06-19 03:31:41 +0000394 if (VI != valueNumbering.end())
395 return VI->second;
396 else
397 assert(0 && "Value not numbered?");
398
399 return 0;
400}
401
Owen Andersonfd5683a2007-06-21 00:19:05 +0000402/// add - Add the specified value with the given value number, removing
403/// its old number, if any
Owen Andersonb56fba02007-06-19 03:31:41 +0000404void ValueTable::add(Value* V, uint32_t num) {
Owen Anderson1ad2c102007-06-19 23:23:54 +0000405 DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
Owen Andersonb56fba02007-06-19 03:31:41 +0000406 if (VI != valueNumbering.end())
407 valueNumbering.erase(VI);
408 valueNumbering.insert(std::make_pair(V, num));
409}
410
Owen Anderson191eb062007-06-25 05:41:12 +0000411/// clear - Remove all entries from the ValueTable
Owen Andersonb56fba02007-06-19 03:31:41 +0000412void ValueTable::clear() {
413 valueNumbering.clear();
414 expressionNumbering.clear();
415 nextValueNumber = 1;
416}
Owen Anderson0b68cda2007-06-03 05:55:58 +0000417
Owen Anderson191eb062007-06-25 05:41:12 +0000418/// erase - Remove a value from the value numbering
Owen Anderson91c54952007-06-19 05:37:32 +0000419void ValueTable::erase(Value* V) {
Owen Anderson91c54952007-06-19 05:37:32 +0000420 valueNumbering.erase(V);
Owen Anderson91c54952007-06-19 05:37:32 +0000421}
422
Owen Anderson28a2d442007-06-22 00:20:30 +0000423/// size - Return the number of assigned value numbers
424unsigned ValueTable::size() {
425 // NOTE: zero is never assigned
426 return nextValueNumber;
427}
428
Owen Andersonfd5683a2007-06-21 00:19:05 +0000429//===----------------------------------------------------------------------===//
430// GVNPRE Pass
431//===----------------------------------------------------------------------===//
432
Owen Anderson5fba6c12007-05-29 21:53:49 +0000433namespace {
434
435 class VISIBILITY_HIDDEN GVNPRE : public FunctionPass {
436 bool runOnFunction(Function &F);
437 public:
438 static char ID; // Pass identification, replacement for typeid
Owen Andersonb9cbaed2007-06-19 04:32:55 +0000439 GVNPRE() : FunctionPass((intptr_t)&ID) { }
Owen Anderson5fba6c12007-05-29 21:53:49 +0000440
441 private:
Owen Andersonbe802402007-06-08 01:03:01 +0000442 ValueTable VN;
Owen Andersona75dd4d2007-06-12 00:50:47 +0000443 std::vector<Instruction*> createdExpressions;
Owen Anderson81d156e2007-05-31 00:42:15 +0000444
Owen Andersone02da552007-06-28 00:34:34 +0000445 std::map<BasicBlock*, SmallPtrSet<Value*, 16> > availableOut;
446 std::map<BasicBlock*, SmallPtrSet<Value*, 16> > anticipatedIn;
Owen Anderson4036ad42007-06-12 22:43:57 +0000447
Owen Andersonfd5683a2007-06-21 00:19:05 +0000448 // This transformation requires dominator postdominator info
Owen Anderson5fba6c12007-05-29 21:53:49 +0000449 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
450 AU.setPreservesCFG();
451 AU.addRequired<DominatorTree>();
Owen Anderson5fba6c12007-05-29 21:53:49 +0000452 }
453
454 // Helper fuctions
455 // FIXME: eliminate or document these better
Owen Andersone02da552007-06-28 00:34:34 +0000456 void dump(const SmallPtrSet<Value*, 16>& s) const;
457 void clean(SmallPtrSet<Value*, 16>& set, BitVector& presentInSet);
458 Value* find_leader(SmallPtrSet<Value*, 16>& vals,
Owen Anderson92c7b222007-06-22 17:04:40 +0000459 uint32_t v);
460 Value* phi_translate(Value* V, BasicBlock* pred, BasicBlock* succ);
Owen Andersone02da552007-06-28 00:34:34 +0000461 void phi_translate_set(SmallPtrSet<Value*, 16>& anticIn, BasicBlock* pred,
462 BasicBlock* succ, SmallPtrSet<Value*, 16>& out);
Owen Anderson5fba6c12007-05-29 21:53:49 +0000463
Owen Andersone02da552007-06-28 00:34:34 +0000464 void topo_sort(SmallPtrSet<Value*, 16>& set,
Owen Anderson92c7b222007-06-22 17:04:40 +0000465 std::vector<Value*>& vec);
Owen Anderson331bf6a2007-05-31 22:44:11 +0000466
Owen Anderson92c7b222007-06-22 17:04:40 +0000467 void cleanup();
468 bool elimination();
Owen Andersondd998e12007-06-18 04:42:29 +0000469
Owen Andersone02da552007-06-28 00:34:34 +0000470 void val_insert(SmallPtrSet<Value*, 16>& s, Value* v);
471 void val_replace(SmallPtrSet<Value*, 16>& s, Value* v);
Owen Anderson92c7b222007-06-22 17:04:40 +0000472 bool dependsOnInvoke(Value* V);
Owen Anderson06c1e582007-06-20 22:10:02 +0000473 void buildsets_availout(BasicBlock::iterator I,
Owen Andersone02da552007-06-28 00:34:34 +0000474 SmallPtrSet<Value*, 16>& currAvail,
475 SmallPtrSet<PHINode*, 16>& currPhis,
476 SmallPtrSet<Value*, 16>& currExps,
477 SmallPtrSet<Value*, 16>& currTemps,
Owen Andersonf6e21872007-06-22 03:14:03 +0000478 BitVector& availNumbers,
Owen Anderson92c7b222007-06-22 17:04:40 +0000479 BitVector& expNumbers);
Owen Anderson28a2d442007-06-22 00:20:30 +0000480 bool buildsets_anticout(BasicBlock* BB,
Owen Andersone02da552007-06-28 00:34:34 +0000481 SmallPtrSet<Value*, 16>& anticOut,
Owen Anderson92c7b222007-06-22 17:04:40 +0000482 std::set<BasicBlock*>& visited);
Owen Anderson28a2d442007-06-22 00:20:30 +0000483 unsigned buildsets_anticin(BasicBlock* BB,
Owen Andersone02da552007-06-28 00:34:34 +0000484 SmallPtrSet<Value*, 16>& anticOut,
485 SmallPtrSet<Value*, 16>& currExps,
486 SmallPtrSet<Value*, 16>& currTemps,
Owen Anderson92c7b222007-06-22 17:04:40 +0000487 std::set<BasicBlock*>& visited);
Owen Anderson5477c542007-06-26 23:29:41 +0000488 void buildsets(Function& F);
Owen Anderson06c1e582007-06-20 22:10:02 +0000489
490 void insertion_pre(Value* e, BasicBlock* BB,
491 std::map<BasicBlock*, Value*>& avail,
Owen Andersone02da552007-06-28 00:34:34 +0000492 SmallPtrSet<Value*, 16>& new_set);
Owen Anderson06c1e582007-06-20 22:10:02 +0000493 unsigned insertion_mergepoint(std::vector<Value*>& workList,
Owen Anderson28a2d442007-06-22 00:20:30 +0000494 df_iterator<DomTreeNode*>& D,
Owen Andersone02da552007-06-28 00:34:34 +0000495 SmallPtrSet<Value*, 16>& new_set);
Owen Anderson92c7b222007-06-22 17:04:40 +0000496 bool insertion(Function& F);
Owen Anderson5fba6c12007-05-29 21:53:49 +0000497
498 };
499
500 char GVNPRE::ID = 0;
501
502}
503
Owen Andersonfd5683a2007-06-21 00:19:05 +0000504// createGVNPREPass - The public interface to this file...
Owen Anderson5fba6c12007-05-29 21:53:49 +0000505FunctionPass *llvm::createGVNPREPass() { return new GVNPRE(); }
506
507RegisterPass<GVNPRE> X("gvnpre",
508 "Global Value Numbering/Partial Redundancy Elimination");
509
Owen Anderson5fba6c12007-05-29 21:53:49 +0000510
Owen Anderson7d76b2a2007-06-08 22:02:36 +0000511STATISTIC(NumInsertedVals, "Number of values inserted");
512STATISTIC(NumInsertedPhis, "Number of PHI nodes inserted");
513STATISTIC(NumEliminated, "Number of redundant instructions eliminated");
514
Owen Andersonfd5683a2007-06-21 00:19:05 +0000515/// find_leader - Given a set and a value number, return the first
516/// element of the set with that value number, or 0 if no such element
517/// is present
Owen Andersone02da552007-06-28 00:34:34 +0000518Value* GVNPRE::find_leader(SmallPtrSet<Value*, 16>& vals, uint32_t v) {
519 for (SmallPtrSet<Value*, 16>::iterator I = vals.begin(), E = vals.end();
Owen Andersonb56fba02007-06-19 03:31:41 +0000520 I != E; ++I)
521 if (v == VN.lookup(*I))
Owen Anderson0b68cda2007-06-03 05:55:58 +0000522 return *I;
Owen Anderson5fba6c12007-05-29 21:53:49 +0000523
Owen Anderson0b68cda2007-06-03 05:55:58 +0000524 return 0;
Owen Anderson5fba6c12007-05-29 21:53:49 +0000525}
526
Owen Andersonfd5683a2007-06-21 00:19:05 +0000527/// val_insert - Insert a value into a set only if there is not a value
528/// with the same value number already in the set
Owen Andersone02da552007-06-28 00:34:34 +0000529void GVNPRE::val_insert(SmallPtrSet<Value*, 16>& s, Value* v) {
Owen Andersonb56fba02007-06-19 03:31:41 +0000530 uint32_t num = VN.lookup(v);
531 Value* leader = find_leader(s, num);
532 if (leader == 0)
533 s.insert(v);
534}
535
Owen Andersonfd5683a2007-06-21 00:19:05 +0000536/// val_replace - Insert a value into a set, replacing any values already in
537/// the set that have the same value number
Owen Andersone02da552007-06-28 00:34:34 +0000538void GVNPRE::val_replace(SmallPtrSet<Value*, 16>& s, Value* v) {
Owen Andersonb56fba02007-06-19 03:31:41 +0000539 uint32_t num = VN.lookup(v);
540 Value* leader = find_leader(s, num);
541 while (leader != 0) {
542 s.erase(leader);
543 leader = find_leader(s, num);
544 }
545 s.insert(v);
546}
547
Owen Andersonfd5683a2007-06-21 00:19:05 +0000548/// phi_translate - Given a value, its parent block, and a predecessor of its
549/// parent, translate the value into legal for the predecessor block. This
550/// means translating its operands (and recursively, their operands) through
551/// any phi nodes in the parent into values available in the predecessor
Owen Anderson4036ad42007-06-12 22:43:57 +0000552Value* GVNPRE::phi_translate(Value* V, BasicBlock* pred, BasicBlock* succ) {
Owen Anderson38b6b222007-06-04 18:05:26 +0000553 if (V == 0)
554 return 0;
555
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000556 // Binary Operations
557 if (isa<BinaryOperator>(V) || isa<CmpInst>(V) ||
558 isa<ExtractElementInst>(V)) {
Owen Anderson191eb062007-06-25 05:41:12 +0000559 User* U = cast<User>(V);
560
Owen Andersonb56fba02007-06-19 03:31:41 +0000561 Value* newOp1 = 0;
Owen Anderson191eb062007-06-25 05:41:12 +0000562 if (isa<Instruction>(U->getOperand(0)))
563 newOp1 = phi_translate(U->getOperand(0), pred, succ);
Owen Andersonb56fba02007-06-19 03:31:41 +0000564 else
Owen Anderson191eb062007-06-25 05:41:12 +0000565 newOp1 = U->getOperand(0);
Owen Andersonb56fba02007-06-19 03:31:41 +0000566
Owen Anderson38b6b222007-06-04 18:05:26 +0000567 if (newOp1 == 0)
568 return 0;
569
Owen Andersonb56fba02007-06-19 03:31:41 +0000570 Value* newOp2 = 0;
Owen Anderson191eb062007-06-25 05:41:12 +0000571 if (isa<Instruction>(U->getOperand(1)))
572 newOp2 = phi_translate(U->getOperand(1), pred, succ);
Owen Andersonb56fba02007-06-19 03:31:41 +0000573 else
Owen Anderson191eb062007-06-25 05:41:12 +0000574 newOp2 = U->getOperand(1);
Owen Andersonb56fba02007-06-19 03:31:41 +0000575
Owen Anderson38b6b222007-06-04 18:05:26 +0000576 if (newOp2 == 0)
577 return 0;
578
Owen Anderson191eb062007-06-25 05:41:12 +0000579 if (newOp1 != U->getOperand(0) || newOp2 != U->getOperand(1)) {
580 Instruction* newVal = 0;
581 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(U))
582 newVal = BinaryOperator::create(BO->getOpcode(),
583 newOp1, newOp2,
584 BO->getName()+".expr");
585 else if (CmpInst* C = dyn_cast<CmpInst>(U))
586 newVal = CmpInst::create(C->getOpcode(),
587 C->getPredicate(),
588 newOp1, newOp2,
589 C->getName()+".expr");
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000590 else if (ExtractElementInst* E = dyn_cast<ExtractElementInst>(U))
591 newVal = new ExtractElementInst(newOp1, newOp2, E->getName()+".expr");
Owen Anderson55994f22007-06-08 20:44:02 +0000592
Owen Andersonb56fba02007-06-19 03:31:41 +0000593 uint32_t v = VN.lookup_or_add(newVal);
Owen Anderson4036ad42007-06-12 22:43:57 +0000594
Owen Andersonb56fba02007-06-19 03:31:41 +0000595 Value* leader = find_leader(availableOut[pred], v);
Owen Anderson4036ad42007-06-12 22:43:57 +0000596 if (leader == 0) {
Owen Andersona75dd4d2007-06-12 00:50:47 +0000597 createdExpressions.push_back(newVal);
Owen Anderson38b6b222007-06-04 18:05:26 +0000598 return newVal;
Owen Andersonc8472092007-06-05 22:11:49 +0000599 } else {
Owen Anderson91c54952007-06-19 05:37:32 +0000600 VN.erase(newVal);
Owen Andersonc8472092007-06-05 22:11:49 +0000601 delete newVal;
Owen Anderson4036ad42007-06-12 22:43:57 +0000602 return leader;
Owen Andersonc8472092007-06-05 22:11:49 +0000603 }
Owen Anderson38b6b222007-06-04 18:05:26 +0000604 }
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000605
606 // Ternary Operations
Owen Anderson8a9fa5d2007-06-28 23:51:21 +0000607 } else if (isa<ShuffleVectorInst>(V) || isa<InsertElementInst>(V) ||
608 isa<SelectInst>(V)) {
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000609 User* U = cast<User>(V);
610
611 Value* newOp1 = 0;
612 if (isa<Instruction>(U->getOperand(0)))
613 newOp1 = phi_translate(U->getOperand(0), pred, succ);
614 else
615 newOp1 = U->getOperand(0);
616
617 if (newOp1 == 0)
618 return 0;
619
620 Value* newOp2 = 0;
621 if (isa<Instruction>(U->getOperand(1)))
622 newOp2 = phi_translate(U->getOperand(1), pred, succ);
623 else
624 newOp2 = U->getOperand(1);
625
626 if (newOp2 == 0)
627 return 0;
628
629 Value* newOp3 = 0;
630 if (isa<Instruction>(U->getOperand(2)))
631 newOp3 = phi_translate(U->getOperand(2), pred, succ);
632 else
633 newOp3 = U->getOperand(2);
634
635 if (newOp3 == 0)
636 return 0;
637
638 if (newOp1 != U->getOperand(0) ||
639 newOp2 != U->getOperand(1) ||
640 newOp3 != U->getOperand(2)) {
641 Instruction* newVal = 0;
642 if (ShuffleVectorInst* S = dyn_cast<ShuffleVectorInst>(U))
643 newVal = new ShuffleVectorInst(newOp1, newOp2, newOp3,
644 S->getName()+".expr");
645 else if (InsertElementInst* I = dyn_cast<InsertElementInst>(U))
646 newVal = new InsertElementInst(newOp1, newOp2, newOp3,
647 I->getName()+".expr");
Owen Anderson8a9fa5d2007-06-28 23:51:21 +0000648 else if (SelectInst* I = dyn_cast<SelectInst>(U))
649 newVal = new SelectInst(newOp1, newOp2, newOp3, I->getName()+".expr");
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000650
651 uint32_t v = VN.lookup_or_add(newVal);
652
653 Value* leader = find_leader(availableOut[pred], v);
654 if (leader == 0) {
655 createdExpressions.push_back(newVal);
656 return newVal;
657 } else {
658 VN.erase(newVal);
659 delete newVal;
660 return leader;
661 }
662 }
663
664 // PHI Nodes
Owen Anderson38b6b222007-06-04 18:05:26 +0000665 } else if (PHINode* P = dyn_cast<PHINode>(V)) {
Owen Andersona75dd4d2007-06-12 00:50:47 +0000666 if (P->getParent() == succ)
Owen Anderson38b6b222007-06-04 18:05:26 +0000667 return P->getIncomingValueForBlock(pred);
668 }
669
670 return V;
671}
672
Owen Andersonfd5683a2007-06-21 00:19:05 +0000673/// phi_translate_set - Perform phi translation on every element of a set
Owen Andersone02da552007-06-28 00:34:34 +0000674void GVNPRE::phi_translate_set(SmallPtrSet<Value*, 16>& anticIn,
Owen Andersona75dd4d2007-06-12 00:50:47 +0000675 BasicBlock* pred, BasicBlock* succ,
Owen Andersone02da552007-06-28 00:34:34 +0000676 SmallPtrSet<Value*, 16>& out) {
677 for (SmallPtrSet<Value*, 16>::iterator I = anticIn.begin(),
Owen Anderson38b6b222007-06-04 18:05:26 +0000678 E = anticIn.end(); I != E; ++I) {
Owen Anderson4036ad42007-06-12 22:43:57 +0000679 Value* V = phi_translate(*I, pred, succ);
Owen Anderson38b6b222007-06-04 18:05:26 +0000680 if (V != 0)
681 out.insert(V);
Owen Anderson5fba6c12007-05-29 21:53:49 +0000682 }
683}
684
Owen Andersonfd5683a2007-06-21 00:19:05 +0000685/// dependsOnInvoke - Test if a value has an phi node as an operand, any of
686/// whose inputs is an invoke instruction. If this is true, we cannot safely
687/// PRE the instruction or anything that depends on it.
Owen Andersondd998e12007-06-18 04:42:29 +0000688bool GVNPRE::dependsOnInvoke(Value* V) {
Owen Anderson2320d432007-06-19 23:07:16 +0000689 if (PHINode* p = dyn_cast<PHINode>(V)) {
690 for (PHINode::op_iterator I = p->op_begin(), E = p->op_end(); I != E; ++I)
691 if (isa<InvokeInst>(*I))
Owen Andersondd998e12007-06-18 04:42:29 +0000692 return true;
Owen Anderson2320d432007-06-19 23:07:16 +0000693 return false;
694 } else {
695 return false;
Owen Anderson658f2c42007-06-16 00:26:54 +0000696 }
Owen Anderson658f2c42007-06-16 00:26:54 +0000697}
698
Owen Andersonfd5683a2007-06-21 00:19:05 +0000699/// clean - Remove all non-opaque values from the set whose operands are not
700/// themselves in the set, as well as all values that depend on invokes (see
701/// above)
Owen Andersone02da552007-06-28 00:34:34 +0000702void GVNPRE::clean(SmallPtrSet<Value*, 16>& set, BitVector& presentInSet) {
Owen Anderson0b68cda2007-06-03 05:55:58 +0000703 std::vector<Value*> worklist;
Owen Andersond50a29d2007-06-22 00:43:22 +0000704 worklist.reserve(set.size());
Owen Andersonbe802402007-06-08 01:03:01 +0000705 topo_sort(set, worklist);
Owen Anderson5fba6c12007-05-29 21:53:49 +0000706
Owen Andersonbe802402007-06-08 01:03:01 +0000707 for (unsigned i = 0; i < worklist.size(); ++i) {
708 Value* v = worklist[i];
Owen Anderson5fba6c12007-05-29 21:53:49 +0000709
Owen Anderson0eb26572007-06-27 17:03:03 +0000710 // Handle binary ops
711 if (isa<BinaryOperator>(v) || isa<CmpInst>(v) ||
712 isa<ExtractElementInst>(v)) {
713 User* U = cast<User>(v);
714
715 bool lhsValid = !isa<Instruction>(U->getOperand(0));
Owen Anderson7dae8ef2007-06-27 17:38:29 +0000716 lhsValid |= presentInSet.test(VN.lookup(U->getOperand(0)));
Owen Andersonb364b412007-06-18 04:30:44 +0000717 if (lhsValid)
Owen Anderson0eb26572007-06-27 17:03:03 +0000718 lhsValid = !dependsOnInvoke(U->getOperand(0));
Owen Anderson0b68cda2007-06-03 05:55:58 +0000719
Owen Anderson0eb26572007-06-27 17:03:03 +0000720 bool rhsValid = !isa<Instruction>(U->getOperand(1));
Owen Anderson7dae8ef2007-06-27 17:38:29 +0000721 rhsValid |= presentInSet.test(VN.lookup(U->getOperand(1)));
Owen Andersonb364b412007-06-18 04:30:44 +0000722 if (rhsValid)
Owen Anderson0eb26572007-06-27 17:03:03 +0000723 rhsValid = !dependsOnInvoke(U->getOperand(1));
Owen Anderson5fba6c12007-05-29 21:53:49 +0000724
Owen Anderson7dae8ef2007-06-27 17:38:29 +0000725 if (!lhsValid || !rhsValid) {
Owen Anderson0eb26572007-06-27 17:03:03 +0000726 set.erase(U);
Owen Anderson7dae8ef2007-06-27 17:38:29 +0000727 presentInSet.flip(VN.lookup(U));
728 }
Owen Anderson223718c2007-06-09 18:35:31 +0000729
Owen Anderson0eb26572007-06-27 17:03:03 +0000730 // Handle ternary ops
Owen Anderson8a9fa5d2007-06-28 23:51:21 +0000731 } else if (isa<ShuffleVectorInst>(v) || isa<InsertElementInst>(v) ||
732 isa<SelectInst>(v)) {
Owen Anderson0eb26572007-06-27 17:03:03 +0000733 User* U = cast<User>(v);
734
735 bool lhsValid = !isa<Instruction>(U->getOperand(0));
Owen Anderson7dae8ef2007-06-27 17:38:29 +0000736 lhsValid |= presentInSet.test(VN.lookup(U->getOperand(0)));
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000737 if (lhsValid)
Owen Anderson0eb26572007-06-27 17:03:03 +0000738 lhsValid = !dependsOnInvoke(U->getOperand(0));
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000739
Owen Anderson0eb26572007-06-27 17:03:03 +0000740 bool rhsValid = !isa<Instruction>(U->getOperand(1));
Owen Anderson7dae8ef2007-06-27 17:38:29 +0000741 rhsValid |= presentInSet.test(VN.lookup(U->getOperand(1)));
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000742 if (rhsValid)
Owen Anderson0eb26572007-06-27 17:03:03 +0000743 rhsValid = !dependsOnInvoke(U->getOperand(1));
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000744
Owen Anderson0eb26572007-06-27 17:03:03 +0000745 bool thirdValid = !isa<Instruction>(U->getOperand(2));
Owen Anderson7dae8ef2007-06-27 17:38:29 +0000746 thirdValid |= presentInSet.test(VN.lookup(U->getOperand(2)));
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000747 if (thirdValid)
Owen Anderson0eb26572007-06-27 17:03:03 +0000748 thirdValid = !dependsOnInvoke(U->getOperand(2));
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000749
Owen Anderson7dae8ef2007-06-27 17:38:29 +0000750 if (!lhsValid || !rhsValid || !thirdValid) {
Owen Anderson0eb26572007-06-27 17:03:03 +0000751 set.erase(U);
Owen Anderson7dae8ef2007-06-27 17:38:29 +0000752 presentInSet.flip(VN.lookup(U));
753 }
Owen Anderson0b68cda2007-06-03 05:55:58 +0000754 }
Owen Anderson5fba6c12007-05-29 21:53:49 +0000755 }
756}
757
Owen Andersonfd5683a2007-06-21 00:19:05 +0000758/// topo_sort - Given a set of values, sort them by topological
759/// order into the provided vector.
Owen Andersone02da552007-06-28 00:34:34 +0000760void GVNPRE::topo_sort(SmallPtrSet<Value*, 16>& set, std::vector<Value*>& vec) {
761 SmallPtrSet<Value*, 16> visited;
Owen Anderson49409f62007-06-22 21:31:16 +0000762 std::vector<Value*> stack;
Owen Andersone02da552007-06-28 00:34:34 +0000763 for (SmallPtrSet<Value*, 16>::iterator I = set.begin(), E = set.end();
Owen Anderson49409f62007-06-22 21:31:16 +0000764 I != E; ++I) {
765 if (visited.count(*I) == 0)
766 stack.push_back(*I);
767
768 while (!stack.empty()) {
769 Value* e = stack.back();
Owen Anderson0b68cda2007-06-03 05:55:58 +0000770
Owen Anderson0eb26572007-06-27 17:03:03 +0000771 // Handle binary ops
772 if (isa<BinaryOperator>(e) || isa<CmpInst>(e) ||
773 isa<ExtractElementInst>(e)) {
774 User* U = cast<User>(e);
775 Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
776 Value* r = find_leader(set, VN.lookup(U->getOperand(1)));
Owen Anderson49409f62007-06-22 21:31:16 +0000777
778 if (l != 0 && isa<Instruction>(l) &&
779 visited.count(l) == 0)
780 stack.push_back(l);
781 else if (r != 0 && isa<Instruction>(r) &&
782 visited.count(r) == 0)
783 stack.push_back(r);
784 else {
785 vec.push_back(e);
786 visited.insert(e);
787 stack.pop_back();
788 }
Owen Anderson0b68cda2007-06-03 05:55:58 +0000789
Owen Anderson0eb26572007-06-27 17:03:03 +0000790 // Handle ternary ops
Owen Anderson8a9fa5d2007-06-28 23:51:21 +0000791 } else if (isa<InsertElementInst>(e) || isa<ShuffleVectorInst>(e) ||
792 isa<SelectInst>(e)) {
Owen Anderson0eb26572007-06-27 17:03:03 +0000793 User* U = cast<User>(e);
794 Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
795 Value* r = find_leader(set, VN.lookup(U->getOperand(1)));
796 Value* m = find_leader(set, VN.lookup(U->getOperand(2)));
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000797
798 if (l != 0 && isa<Instruction>(l) &&
799 visited.count(l) == 0)
800 stack.push_back(l);
801 else if (r != 0 && isa<Instruction>(r) &&
802 visited.count(r) == 0)
803 stack.push_back(r);
804 else if (m != 0 && isa<Instruction>(m) &&
805 visited.count(m) == 0)
806 stack.push_back(r);
807 else {
808 vec.push_back(e);
809 visited.insert(e);
810 stack.pop_back();
811 }
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000812
Owen Anderson0eb26572007-06-27 17:03:03 +0000813 // Handle opaque ops
Owen Anderson49409f62007-06-22 21:31:16 +0000814 } else {
Owen Anderson0b68cda2007-06-03 05:55:58 +0000815 visited.insert(e);
Owen Anderson223718c2007-06-09 18:35:31 +0000816 vec.push_back(e);
Owen Anderson49409f62007-06-22 21:31:16 +0000817 stack.pop_back();
Owen Anderson223718c2007-06-09 18:35:31 +0000818 }
Owen Anderson331bf6a2007-05-31 22:44:11 +0000819 }
Owen Anderson49409f62007-06-22 21:31:16 +0000820
821 stack.clear();
Owen Anderson331bf6a2007-05-31 22:44:11 +0000822 }
823}
824
Owen Andersonfd5683a2007-06-21 00:19:05 +0000825/// dump - Dump a set of values to standard error
Owen Andersone02da552007-06-28 00:34:34 +0000826void GVNPRE::dump(const SmallPtrSet<Value*, 16>& s) const {
Owen Anderson4a6ec8f2007-05-29 23:15:21 +0000827 DOUT << "{ ";
Owen Andersone02da552007-06-28 00:34:34 +0000828 for (SmallPtrSet<Value*, 16>::iterator I = s.begin(), E = s.end();
Owen Anderson0eca9aa2007-06-03 22:02:14 +0000829 I != E; ++I) {
Owen Anderson8a9fa5d2007-06-28 23:51:21 +0000830 DOUT << "" << VN.lookup(*I) << ": ";
Owen Anderson0eca9aa2007-06-03 22:02:14 +0000831 DEBUG((*I)->dump());
832 }
833 DOUT << "}\n\n";
834}
835
Owen Andersonfd5683a2007-06-21 00:19:05 +0000836/// elimination - Phase 3 of the main algorithm. Perform full redundancy
837/// elimination by walking the dominator tree and removing any instruction that
838/// is dominated by another instruction with the same value number.
Owen Anderson06c1e582007-06-20 22:10:02 +0000839bool GVNPRE::elimination() {
Owen Anderson42769842007-06-12 16:57:50 +0000840 DOUT << "\n\nPhase 3: Elimination\n\n";
841
Owen Anderson06c1e582007-06-20 22:10:02 +0000842 bool changed_function = false;
843
Owen Anderson42769842007-06-12 16:57:50 +0000844 std::vector<std::pair<Instruction*, Value*> > replace;
845 std::vector<Instruction*> erase;
846
847 DominatorTree& DT = getAnalysis<DominatorTree>();
848
849 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
850 E = df_end(DT.getRootNode()); DI != E; ++DI) {
851 BasicBlock* BB = DI->getBlock();
852
Owen Anderson191eb062007-06-25 05:41:12 +0000853 //DOUT << "Block: " << BB->getName() << "\n";
854 //dump(availableOut[BB]);
855 //DOUT << "\n\n";
Owen Anderson42769842007-06-12 16:57:50 +0000856
857 for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
858 BI != BE; ++BI) {
859
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000860 if (isa<BinaryOperator>(BI) || isa<CmpInst>(BI) ||
861 isa<ShuffleVectorInst>(BI) || isa<InsertElementInst>(BI) ||
Owen Anderson8a9fa5d2007-06-28 23:51:21 +0000862 isa<ExtractElementInst>(BI) || isa<SelectInst>(BI)) {
Owen Andersonb56fba02007-06-19 03:31:41 +0000863 Value *leader = find_leader(availableOut[BB], VN.lookup(BI));
Owen Anderson42769842007-06-12 16:57:50 +0000864
865 if (leader != 0)
866 if (Instruction* Instr = dyn_cast<Instruction>(leader))
867 if (Instr->getParent() != 0 && Instr != BI) {
868 replace.push_back(std::make_pair(BI, leader));
869 erase.push_back(BI);
870 ++NumEliminated;
871 }
872 }
873 }
874 }
875
876 while (!replace.empty()) {
877 std::pair<Instruction*, Value*> rep = replace.back();
878 replace.pop_back();
879 rep.first->replaceAllUsesWith(rep.second);
Owen Andersonb0714bb2007-06-20 18:30:20 +0000880 changed_function = true;
Owen Anderson42769842007-06-12 16:57:50 +0000881 }
882
883 for (std::vector<Instruction*>::iterator I = erase.begin(), E = erase.end();
884 I != E; ++I)
885 (*I)->eraseFromParent();
Owen Anderson06c1e582007-06-20 22:10:02 +0000886
887 return changed_function;
Owen Anderson42769842007-06-12 16:57:50 +0000888}
889
Owen Andersonfd5683a2007-06-21 00:19:05 +0000890/// cleanup - Delete any extraneous values that were created to represent
891/// expressions without leaders.
Owen Anderson42769842007-06-12 16:57:50 +0000892void GVNPRE::cleanup() {
893 while (!createdExpressions.empty()) {
894 Instruction* I = createdExpressions.back();
895 createdExpressions.pop_back();
896
897 delete I;
898 }
899}
900
Owen Andersonfd5683a2007-06-21 00:19:05 +0000901/// buildsets_availout - When calculating availability, handle an instruction
902/// by inserting it into the appropriate sets
Owen Anderson06c1e582007-06-20 22:10:02 +0000903void GVNPRE::buildsets_availout(BasicBlock::iterator I,
Owen Andersone02da552007-06-28 00:34:34 +0000904 SmallPtrSet<Value*, 16>& currAvail,
905 SmallPtrSet<PHINode*, 16>& currPhis,
906 SmallPtrSet<Value*, 16>& currExps,
907 SmallPtrSet<Value*, 16>& currTemps,
Owen Andersonf6e21872007-06-22 03:14:03 +0000908 BitVector& availNumbers,
909 BitVector& expNumbers) {
Owen Anderson0eb26572007-06-27 17:03:03 +0000910 // Handle PHI nodes
Owen Anderson06c1e582007-06-20 22:10:02 +0000911 if (PHINode* p = dyn_cast<PHINode>(I)) {
912 VN.lookup_or_add(p);
Owen Andersonf6e21872007-06-22 03:14:03 +0000913 expNumbers.resize(VN.size());
914 availNumbers.resize(VN.size());
915
Owen Anderson06c1e582007-06-20 22:10:02 +0000916 currPhis.insert(p);
917
Owen Anderson0eb26572007-06-27 17:03:03 +0000918 // Handle binary ops
919 } else if (isa<BinaryOperator>(I) || isa<CmpInst>(I) ||
920 isa<ExtractElementInst>(I)) {
921 User* U = cast<User>(I);
922 Value* leftValue = U->getOperand(0);
923 Value* rightValue = U->getOperand(1);
Owen Anderson06c1e582007-06-20 22:10:02 +0000924
Owen Anderson0eb26572007-06-27 17:03:03 +0000925 unsigned num = VN.lookup_or_add(U);
Owen Andersonf6e21872007-06-22 03:14:03 +0000926 expNumbers.resize(VN.size());
927 availNumbers.resize(VN.size());
Owen Anderson06c1e582007-06-20 22:10:02 +0000928
929 if (isa<Instruction>(leftValue))
Owen Anderson21a11312007-06-22 18:27:04 +0000930 if (!expNumbers.test(VN.lookup(leftValue))) {
Owen Andersonf6e21872007-06-22 03:14:03 +0000931 currExps.insert(leftValue);
Owen Anderson21a11312007-06-22 18:27:04 +0000932 expNumbers.set(VN.lookup(leftValue));
Owen Andersonf6e21872007-06-22 03:14:03 +0000933 }
934
Owen Anderson06c1e582007-06-20 22:10:02 +0000935 if (isa<Instruction>(rightValue))
Owen Anderson21a11312007-06-22 18:27:04 +0000936 if (!expNumbers.test(VN.lookup(rightValue))) {
Owen Andersonf6e21872007-06-22 03:14:03 +0000937 currExps.insert(rightValue);
Owen Anderson21a11312007-06-22 18:27:04 +0000938 expNumbers.set(VN.lookup(rightValue));
Owen Andersonf6e21872007-06-22 03:14:03 +0000939 }
940
Owen Anderson0eb26572007-06-27 17:03:03 +0000941 if (!expNumbers.test(VN.lookup(U))) {
942 currExps.insert(U);
Owen Anderson21a11312007-06-22 18:27:04 +0000943 expNumbers.set(num);
Owen Andersonf6e21872007-06-22 03:14:03 +0000944 }
Owen Anderson06c1e582007-06-20 22:10:02 +0000945
Owen Anderson0eb26572007-06-27 17:03:03 +0000946 // Handle ternary ops
Owen Anderson8a9fa5d2007-06-28 23:51:21 +0000947 } else if (isa<InsertElementInst>(I) || isa<ShuffleVectorInst>(I) ||
948 isa<SelectInst>(I)) {
Owen Anderson0eb26572007-06-27 17:03:03 +0000949 User* U = cast<User>(I);
950 Value* leftValue = U->getOperand(0);
951 Value* rightValue = U->getOperand(1);
952 Value* thirdValue = U->getOperand(2);
Owen Anderson06c1e582007-06-20 22:10:02 +0000953
Owen Anderson0eb26572007-06-27 17:03:03 +0000954 VN.lookup_or_add(U);
Owen Andersonf6e21872007-06-22 03:14:03 +0000955
Owen Anderson0eb26572007-06-27 17:03:03 +0000956 unsigned num = VN.lookup_or_add(U);
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000957 expNumbers.resize(VN.size());
958 availNumbers.resize(VN.size());
959
960 if (isa<Instruction>(leftValue))
961 if (!expNumbers.test(VN.lookup(leftValue))) {
962 currExps.insert(leftValue);
963 expNumbers.set(VN.lookup(leftValue));
964 }
965 if (isa<Instruction>(rightValue))
966 if (!expNumbers.test(VN.lookup(rightValue))) {
967 currExps.insert(rightValue);
968 expNumbers.set(VN.lookup(rightValue));
969 }
970 if (isa<Instruction>(thirdValue))
971 if (!expNumbers.test(VN.lookup(thirdValue))) {
972 currExps.insert(thirdValue);
973 expNumbers.set(VN.lookup(thirdValue));
974 }
975
Owen Anderson0eb26572007-06-27 17:03:03 +0000976 if (!expNumbers.test(VN.lookup(U))) {
977 currExps.insert(U);
Owen Andersonb6a39fc2007-06-27 04:10:46 +0000978 expNumbers.set(num);
979 }
980
Owen Anderson0eb26572007-06-27 17:03:03 +0000981 // Handle opaque ops
982 } else if (!I->isTerminator()){
Owen Anderson06c1e582007-06-20 22:10:02 +0000983 VN.lookup_or_add(I);
Owen Andersonf6e21872007-06-22 03:14:03 +0000984 expNumbers.resize(VN.size());
985 availNumbers.resize(VN.size());
986
Owen Anderson06c1e582007-06-20 22:10:02 +0000987 currTemps.insert(I);
988 }
989
990 if (!I->isTerminator())
Owen Anderson21a11312007-06-22 18:27:04 +0000991 if (!availNumbers.test(VN.lookup(I))) {
Owen Andersonf6e21872007-06-22 03:14:03 +0000992 currAvail.insert(I);
Owen Anderson21a11312007-06-22 18:27:04 +0000993 availNumbers.set(VN.lookup(I));
Owen Andersonf6e21872007-06-22 03:14:03 +0000994 }
Owen Anderson06c1e582007-06-20 22:10:02 +0000995}
Owen Anderson5fba6c12007-05-29 21:53:49 +0000996
Owen Andersonfd5683a2007-06-21 00:19:05 +0000997/// buildsets_anticout - When walking the postdom tree, calculate the ANTIC_OUT
998/// set as a function of the ANTIC_IN set of the block's predecessors
Owen Anderson28a2d442007-06-22 00:20:30 +0000999bool GVNPRE::buildsets_anticout(BasicBlock* BB,
Owen Andersone02da552007-06-28 00:34:34 +00001000 SmallPtrSet<Value*, 16>& anticOut,
Owen Anderson06c1e582007-06-20 22:10:02 +00001001 std::set<BasicBlock*>& visited) {
1002 if (BB->getTerminator()->getNumSuccessors() == 1) {
Owen Anderson191eb062007-06-25 05:41:12 +00001003 if (BB->getTerminator()->getSuccessor(0) != BB &&
1004 visited.count(BB->getTerminator()->getSuccessor(0)) == 0) {
1005 DOUT << "DEFER: " << BB->getName() << "\n";
Owen Anderson28a2d442007-06-22 00:20:30 +00001006 return true;
Owen Anderson191eb062007-06-25 05:41:12 +00001007 }
1008 else {
Owen Anderson06c1e582007-06-20 22:10:02 +00001009 phi_translate_set(anticipatedIn[BB->getTerminator()->getSuccessor(0)],
1010 BB, BB->getTerminator()->getSuccessor(0), anticOut);
Owen Anderson191eb062007-06-25 05:41:12 +00001011 }
Owen Anderson06c1e582007-06-20 22:10:02 +00001012 } else if (BB->getTerminator()->getNumSuccessors() > 1) {
1013 BasicBlock* first = BB->getTerminator()->getSuccessor(0);
1014 anticOut.insert(anticipatedIn[first].begin(), anticipatedIn[first].end());
1015
1016 for (unsigned i = 1; i < BB->getTerminator()->getNumSuccessors(); ++i) {
1017 BasicBlock* currSucc = BB->getTerminator()->getSuccessor(i);
Owen Andersone02da552007-06-28 00:34:34 +00001018 SmallPtrSet<Value*, 16>& succAnticIn = anticipatedIn[currSucc];
Owen Anderson06c1e582007-06-20 22:10:02 +00001019
Owen Anderson2ff912b2007-06-21 17:57:53 +00001020 std::vector<Value*> temp;
1021
Owen Andersone02da552007-06-28 00:34:34 +00001022 for (SmallPtrSet<Value*, 16>::iterator I = anticOut.begin(),
Owen Anderson2ff912b2007-06-21 17:57:53 +00001023 E = anticOut.end(); I != E; ++I)
1024 if (succAnticIn.count(*I) == 0)
1025 temp.push_back(*I);
1026
1027 for (std::vector<Value*>::iterator I = temp.begin(), E = temp.end();
1028 I != E; ++I)
1029 anticOut.erase(*I);
Owen Anderson06c1e582007-06-20 22:10:02 +00001030 }
1031 }
Owen Anderson28a2d442007-06-22 00:20:30 +00001032
1033 return false;
Owen Anderson06c1e582007-06-20 22:10:02 +00001034}
1035
Owen Andersonfd5683a2007-06-21 00:19:05 +00001036/// buildsets_anticin - Walk the postdom tree, calculating ANTIC_OUT for
1037/// each block. ANTIC_IN is then a function of ANTIC_OUT and the GEN
1038/// sets populated in buildsets_availout
Owen Anderson28a2d442007-06-22 00:20:30 +00001039unsigned GVNPRE::buildsets_anticin(BasicBlock* BB,
Owen Andersone02da552007-06-28 00:34:34 +00001040 SmallPtrSet<Value*, 16>& anticOut,
1041 SmallPtrSet<Value*, 16>& currExps,
1042 SmallPtrSet<Value*, 16>& currTemps,
Owen Anderson06c1e582007-06-20 22:10:02 +00001043 std::set<BasicBlock*>& visited) {
Owen Andersone02da552007-06-28 00:34:34 +00001044 SmallPtrSet<Value*, 16>& anticIn = anticipatedIn[BB];
Owen Anderson21a11312007-06-22 18:27:04 +00001045 unsigned old = anticIn.size();
Owen Anderson06c1e582007-06-20 22:10:02 +00001046
Owen Anderson28a2d442007-06-22 00:20:30 +00001047 bool defer = buildsets_anticout(BB, anticOut, visited);
1048 if (defer)
1049 return 0;
Owen Anderson2ff912b2007-06-21 17:57:53 +00001050
Owen Anderson06c1e582007-06-20 22:10:02 +00001051 anticIn.clear();
Owen Anderson2ff912b2007-06-21 17:57:53 +00001052
Owen Anderson28a2d442007-06-22 00:20:30 +00001053 BitVector numbers(VN.size());
Owen Andersone02da552007-06-28 00:34:34 +00001054 for (SmallPtrSet<Value*, 16>::iterator I = anticOut.begin(),
Owen Anderson21a11312007-06-22 18:27:04 +00001055 E = anticOut.end(); I != E; ++I) {
Owen Anderson191eb062007-06-25 05:41:12 +00001056 unsigned num = VN.lookup_or_add(*I);
1057 numbers.resize(VN.size());
Owen Anderson7dae8ef2007-06-27 17:38:29 +00001058
1059 if (isa<Instruction>(*I)) {
1060 anticIn.insert(*I);
1061 numbers.set(num);
1062 }
Owen Anderson06c1e582007-06-20 22:10:02 +00001063 }
Owen Andersone02da552007-06-28 00:34:34 +00001064 for (SmallPtrSet<Value*, 16>::iterator I = currExps.begin(),
Owen Anderson21a11312007-06-22 18:27:04 +00001065 E = currExps.end(); I != E; ++I) {
1066 if (!numbers.test(VN.lookup_or_add(*I))) {
1067 anticIn.insert(*I);
1068 numbers.set(VN.lookup(*I));
1069 }
1070 }
1071
Owen Andersone02da552007-06-28 00:34:34 +00001072 for (SmallPtrSet<Value*, 16>::iterator I = currTemps.begin(),
Owen Anderson7dae8ef2007-06-27 17:38:29 +00001073 E = currTemps.end(); I != E; ++I) {
Owen Anderson21a11312007-06-22 18:27:04 +00001074 anticIn.erase(*I);
Owen Anderson7dae8ef2007-06-27 17:38:29 +00001075 numbers.flip(VN.lookup(*I));
1076 }
Owen Anderson21a11312007-06-22 18:27:04 +00001077
Owen Anderson7dae8ef2007-06-27 17:38:29 +00001078 clean(anticIn, numbers);
1079 anticOut.clear();
Owen Anderson06c1e582007-06-20 22:10:02 +00001080
Owen Anderson7dae8ef2007-06-27 17:38:29 +00001081 if (old != anticIn.size())
Owen Anderson28a2d442007-06-22 00:20:30 +00001082 return 2;
Owen Anderson7dae8ef2007-06-27 17:38:29 +00001083 else
Owen Anderson28a2d442007-06-22 00:20:30 +00001084 return 1;
Owen Anderson06c1e582007-06-20 22:10:02 +00001085}
1086
Owen Andersonfd5683a2007-06-21 00:19:05 +00001087/// buildsets - Phase 1 of the main algorithm. Construct the AVAIL_OUT
1088/// and the ANTIC_IN sets.
Owen Anderson5477c542007-06-26 23:29:41 +00001089void GVNPRE::buildsets(Function& F) {
Owen Andersone02da552007-06-28 00:34:34 +00001090 std::map<BasicBlock*, SmallPtrSet<Value*, 16> > generatedExpressions;
1091 std::map<BasicBlock*, SmallPtrSet<PHINode*, 16> > generatedPhis;
1092 std::map<BasicBlock*, SmallPtrSet<Value*, 16> > generatedTemporaries;
Owen Anderson06c1e582007-06-20 22:10:02 +00001093
Owen Anderson5fba6c12007-05-29 21:53:49 +00001094 DominatorTree &DT = getAnalysis<DominatorTree>();
1095
Owen Anderson634a0632007-06-06 01:27:49 +00001096 // Phase 1, Part 1: calculate AVAIL_OUT
Owen Anderson5fba6c12007-05-29 21:53:49 +00001097
1098 // Top-down walk of the dominator tree
Devang Patelbdd1aae2007-06-04 00:32:22 +00001099 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
Owen Anderson5fba6c12007-05-29 21:53:49 +00001100 E = df_end(DT.getRootNode()); DI != E; ++DI) {
1101
1102 // Get the sets to update for this block
Owen Andersone02da552007-06-28 00:34:34 +00001103 SmallPtrSet<Value*, 16>& currExps = generatedExpressions[DI->getBlock()];
1104 SmallPtrSet<PHINode*, 16>& currPhis = generatedPhis[DI->getBlock()];
1105 SmallPtrSet<Value*, 16>& currTemps = generatedTemporaries[DI->getBlock()];
1106 SmallPtrSet<Value*, 16>& currAvail = availableOut[DI->getBlock()];
Owen Anderson5fba6c12007-05-29 21:53:49 +00001107
Owen Andersonb56fba02007-06-19 03:31:41 +00001108 BasicBlock* BB = DI->getBlock();
1109
1110 // A block inherits AVAIL_OUT from its dominator
1111 if (DI->getIDom() != 0)
1112 currAvail.insert(availableOut[DI->getIDom()->getBlock()].begin(),
1113 availableOut[DI->getIDom()->getBlock()].end());
1114
Owen Andersonf6e21872007-06-22 03:14:03 +00001115 BitVector availNumbers(VN.size());
Owen Andersone02da552007-06-28 00:34:34 +00001116 for (SmallPtrSet<Value*, 16>::iterator I = currAvail.begin(),
Owen Andersonf6e21872007-06-22 03:14:03 +00001117 E = currAvail.end(); I != E; ++I)
1118 availNumbers.set(VN.lookup(*I));
Owen Andersonb56fba02007-06-19 03:31:41 +00001119
Owen Andersonf6e21872007-06-22 03:14:03 +00001120 BitVector expNumbers(VN.size());
Owen Andersonb56fba02007-06-19 03:31:41 +00001121 for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
Owen Anderson06c1e582007-06-20 22:10:02 +00001122 BI != BE; ++BI)
Owen Andersonf6e21872007-06-22 03:14:03 +00001123 buildsets_availout(BI, currAvail, currPhis, currExps,
1124 currTemps, availNumbers, expNumbers);
Owen Andersonb56fba02007-06-19 03:31:41 +00001125
Owen Anderson5fba6c12007-05-29 21:53:49 +00001126 }
Owen Anderson191eb062007-06-25 05:41:12 +00001127
1128 // Phase 1, Part 2: calculate ANTIC_IN
Owen Anderson5fba6c12007-05-29 21:53:49 +00001129
Owen Anderson0c423072007-05-29 23:26:30 +00001130 std::set<BasicBlock*> visited;
Owen Anderson5477c542007-06-26 23:29:41 +00001131 SmallPtrSet<BasicBlock*, 4> block_changed;
1132 for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
1133 block_changed.insert(FI);
Owen Anderson0c423072007-05-29 23:26:30 +00001134
Owen Anderson5fba6c12007-05-29 21:53:49 +00001135 bool changed = true;
1136 unsigned iterations = 0;
Owen Anderson5477c542007-06-26 23:29:41 +00001137
Owen Anderson5fba6c12007-05-29 21:53:49 +00001138 while (changed) {
1139 changed = false;
Owen Andersone02da552007-06-28 00:34:34 +00001140 SmallPtrSet<Value*, 16> anticOut;
Owen Anderson5fba6c12007-05-29 21:53:49 +00001141
Owen Anderson5477c542007-06-26 23:29:41 +00001142 // Postorder walk of the CFG
Owen Anderson43ca4b42007-06-25 18:25:31 +00001143 for (po_iterator<BasicBlock*> BBI = po_begin(&F.getEntryBlock()),
1144 BBE = po_end(&F.getEntryBlock()); BBI != BBE; ++BBI) {
Owen Anderson191eb062007-06-25 05:41:12 +00001145 BasicBlock* BB = *BBI;
Owen Andersond184c182007-06-11 16:25:17 +00001146
Owen Anderson5477c542007-06-26 23:29:41 +00001147 if (block_changed.count(BB) != 0) {
1148 unsigned ret = buildsets_anticin(BB, anticOut,generatedExpressions[BB],
1149 generatedTemporaries[BB], visited);
Owen Anderson28a2d442007-06-22 00:20:30 +00001150
Owen Anderson5477c542007-06-26 23:29:41 +00001151 if (ret == 0) {
1152 changed = true;
1153 continue;
1154 } else {
1155 visited.insert(BB);
1156
1157 if (ret == 2)
1158 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
1159 PI != PE; ++PI) {
1160 block_changed.insert(*PI);
1161 }
1162 else
1163 block_changed.erase(BB);
1164
1165 changed |= (ret == 2);
Owen Anderson191eb062007-06-25 05:41:12 +00001166 }
Owen Anderson28a2d442007-06-22 00:20:30 +00001167 }
Owen Anderson5fba6c12007-05-29 21:53:49 +00001168 }
Owen Anderson38b6b222007-06-04 18:05:26 +00001169
Owen Anderson5fba6c12007-05-29 21:53:49 +00001170 iterations++;
1171 }
1172
Owen Anderson191eb062007-06-25 05:41:12 +00001173 DOUT << "ITERATIONS: " << iterations << "\n";
Owen Anderson06c1e582007-06-20 22:10:02 +00001174}
1175
Owen Andersonfd5683a2007-06-21 00:19:05 +00001176/// insertion_pre - When a partial redundancy has been identified, eliminate it
1177/// by inserting appropriate values into the predecessors and a phi node in
1178/// the main block
Owen Anderson06c1e582007-06-20 22:10:02 +00001179void GVNPRE::insertion_pre(Value* e, BasicBlock* BB,
1180 std::map<BasicBlock*, Value*>& avail,
Owen Andersone02da552007-06-28 00:34:34 +00001181 SmallPtrSet<Value*, 16>& new_set) {
Owen Anderson06c1e582007-06-20 22:10:02 +00001182 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
1183 Value* e2 = avail[*PI];
1184 if (!find_leader(availableOut[*PI], VN.lookup(e2))) {
1185 User* U = cast<User>(e2);
1186
1187 Value* s1 = 0;
1188 if (isa<BinaryOperator>(U->getOperand(0)) ||
Owen Andersonb6a39fc2007-06-27 04:10:46 +00001189 isa<CmpInst>(U->getOperand(0)) ||
1190 isa<ShuffleVectorInst>(U->getOperand(0)) ||
1191 isa<ExtractElementInst>(U->getOperand(0)) ||
Owen Anderson8a9fa5d2007-06-28 23:51:21 +00001192 isa<InsertElementInst>(U->getOperand(0)) ||
1193 isa<SelectInst>(U->getOperand(0)))
Owen Anderson06c1e582007-06-20 22:10:02 +00001194 s1 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(0)));
1195 else
1196 s1 = U->getOperand(0);
1197
1198 Value* s2 = 0;
Owen Andersonb6a39fc2007-06-27 04:10:46 +00001199 if (isa<BinaryOperator>(U->getOperand(1)) ||
1200 isa<CmpInst>(U->getOperand(1)) ||
1201 isa<ShuffleVectorInst>(U->getOperand(1)) ||
1202 isa<ExtractElementInst>(U->getOperand(1)) ||
Owen Anderson8a9fa5d2007-06-28 23:51:21 +00001203 isa<InsertElementInst>(U->getOperand(1)) ||
1204 isa<SelectInst>(U->getOperand(1)))
Owen Anderson06c1e582007-06-20 22:10:02 +00001205 s2 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(1)));
1206 else
1207 s2 = U->getOperand(1);
Owen Anderson0eb26572007-06-27 17:03:03 +00001208
1209 // Ternary Operators
Owen Andersonb6a39fc2007-06-27 04:10:46 +00001210 Value* s3 = 0;
1211 if (isa<ShuffleVectorInst>(U) ||
Owen Anderson8a9fa5d2007-06-28 23:51:21 +00001212 isa<InsertElementInst>(U) ||
1213 isa<SelectInst>(U))
Owen Andersonb6a39fc2007-06-27 04:10:46 +00001214 if (isa<BinaryOperator>(U->getOperand(2)) ||
1215 isa<CmpInst>(U->getOperand(2)) ||
1216 isa<ShuffleVectorInst>(U->getOperand(2)) ||
1217 isa<ExtractElementInst>(U->getOperand(2)) ||
Owen Anderson8a9fa5d2007-06-28 23:51:21 +00001218 isa<InsertElementInst>(U->getOperand(2)) ||
1219 isa<SelectInst>(U->getOperand(2)))
Owen Andersonb6a39fc2007-06-27 04:10:46 +00001220 s3 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(2)));
1221 else
1222 s3 = U->getOperand(2);
Owen Anderson06c1e582007-06-20 22:10:02 +00001223
1224 Value* newVal = 0;
1225 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(U))
1226 newVal = BinaryOperator::create(BO->getOpcode(), s1, s2,
1227 BO->getName()+".gvnpre",
1228 (*PI)->getTerminator());
1229 else if (CmpInst* C = dyn_cast<CmpInst>(U))
1230 newVal = CmpInst::create(C->getOpcode(), C->getPredicate(), s1, s2,
1231 C->getName()+".gvnpre",
1232 (*PI)->getTerminator());
Owen Andersonb6a39fc2007-06-27 04:10:46 +00001233 else if (ShuffleVectorInst* S = dyn_cast<ShuffleVectorInst>(U))
1234 newVal = new ShuffleVectorInst(s1, s2, s3, S->getName()+".gvnpre",
1235 (*PI)->getTerminator());
1236 else if (InsertElementInst* S = dyn_cast<InsertElementInst>(U))
1237 newVal = new InsertElementInst(s1, s2, s3, S->getName()+".gvnpre",
1238 (*PI)->getTerminator());
1239 else if (ExtractElementInst* S = dyn_cast<ExtractElementInst>(U))
1240 newVal = new ExtractElementInst(s1, s2, S->getName()+".gvnpre",
1241 (*PI)->getTerminator());
Owen Anderson8a9fa5d2007-06-28 23:51:21 +00001242 else if (SelectInst* S = dyn_cast<SelectInst>(U))
1243 newVal = new SelectInst(S->getCondition(), S->getTrueValue(),
1244 S->getFalseValue(), S->getName()+".gvnpre",
1245 (*PI)->getTerminator());
1246
Owen Anderson06c1e582007-06-20 22:10:02 +00001247
1248 VN.add(newVal, VN.lookup(U));
1249
Owen Andersone02da552007-06-28 00:34:34 +00001250 SmallPtrSet<Value*, 16>& predAvail = availableOut[*PI];
Owen Anderson06c1e582007-06-20 22:10:02 +00001251 val_replace(predAvail, newVal);
Owen Andersonfd5683a2007-06-21 00:19:05 +00001252
Owen Anderson06c1e582007-06-20 22:10:02 +00001253 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1254 if (av != avail.end())
1255 avail.erase(av);
1256 avail.insert(std::make_pair(*PI, newVal));
1257
1258 ++NumInsertedVals;
1259 }
1260 }
1261
1262 PHINode* p = 0;
1263
1264 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
1265 if (p == 0)
1266 p = new PHINode(avail[*PI]->getType(), "gvnpre-join", BB->begin());
1267
1268 p->addIncoming(avail[*PI], *PI);
1269 }
1270
1271 VN.add(p, VN.lookup(e));
Owen Anderson06c1e582007-06-20 22:10:02 +00001272 val_replace(availableOut[BB], p);
Owen Anderson06c1e582007-06-20 22:10:02 +00001273 new_set.insert(p);
1274
1275 ++NumInsertedPhis;
1276}
1277
Owen Andersonfd5683a2007-06-21 00:19:05 +00001278/// insertion_mergepoint - When walking the dom tree, check at each merge
1279/// block for the possibility of a partial redundancy. If present, eliminate it
Owen Anderson06c1e582007-06-20 22:10:02 +00001280unsigned GVNPRE::insertion_mergepoint(std::vector<Value*>& workList,
Owen Anderson28a2d442007-06-22 00:20:30 +00001281 df_iterator<DomTreeNode*>& D,
Owen Andersone02da552007-06-28 00:34:34 +00001282 SmallPtrSet<Value*, 16>& new_set) {
Owen Anderson06c1e582007-06-20 22:10:02 +00001283 bool changed_function = false;
1284 bool new_stuff = false;
1285
1286 BasicBlock* BB = D->getBlock();
1287 for (unsigned i = 0; i < workList.size(); ++i) {
1288 Value* e = workList[i];
1289
Owen Andersonb6a39fc2007-06-27 04:10:46 +00001290 if (isa<BinaryOperator>(e) || isa<CmpInst>(e) ||
1291 isa<ExtractElementInst>(e) || isa<InsertElementInst>(e) ||
Owen Anderson8a9fa5d2007-06-28 23:51:21 +00001292 isa<ShuffleVectorInst>(e) || isa<SelectInst>(e)) {
Owen Anderson06c1e582007-06-20 22:10:02 +00001293 if (find_leader(availableOut[D->getIDom()->getBlock()],
1294 VN.lookup(e)) != 0)
1295 continue;
1296
1297 std::map<BasicBlock*, Value*> avail;
1298 bool by_some = false;
1299 int num_avail = 0;
1300
1301 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE;
1302 ++PI) {
1303 Value *e2 = phi_translate(e, *PI, BB);
1304 Value *e3 = find_leader(availableOut[*PI], VN.lookup(e2));
1305
1306 if (e3 == 0) {
1307 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1308 if (av != avail.end())
1309 avail.erase(av);
1310 avail.insert(std::make_pair(*PI, e2));
1311 } else {
1312 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1313 if (av != avail.end())
1314 avail.erase(av);
1315 avail.insert(std::make_pair(*PI, e3));
1316
1317 by_some = true;
1318 num_avail++;
1319 }
1320 }
1321
1322 if (by_some && num_avail < std::distance(pred_begin(BB), pred_end(BB))) {
1323 insertion_pre(e, BB, avail, new_set);
1324
1325 changed_function = true;
1326 new_stuff = true;
1327 }
1328 }
1329 }
1330
1331 unsigned retval = 0;
1332 if (changed_function)
1333 retval += 1;
1334 if (new_stuff)
1335 retval += 2;
1336
1337 return retval;
1338}
1339
Owen Andersonfd5683a2007-06-21 00:19:05 +00001340/// insert - Phase 2 of the main algorithm. Walk the dominator tree looking for
1341/// merge points. When one is found, check for a partial redundancy. If one is
1342/// present, eliminate it. Repeat this walk until no changes are made.
Owen Anderson06c1e582007-06-20 22:10:02 +00001343bool GVNPRE::insertion(Function& F) {
1344 bool changed_function = false;
1345
1346 DominatorTree &DT = getAnalysis<DominatorTree>();
Owen Andersonbe802402007-06-08 01:03:01 +00001347
Owen Andersone02da552007-06-28 00:34:34 +00001348 std::map<BasicBlock*, SmallPtrSet<Value*, 16> > new_sets;
Owen Andersonbe802402007-06-08 01:03:01 +00001349 bool new_stuff = true;
1350 while (new_stuff) {
1351 new_stuff = false;
Owen Andersonbe802402007-06-08 01:03:01 +00001352 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
1353 E = df_end(DT.getRootNode()); DI != E; ++DI) {
1354 BasicBlock* BB = DI->getBlock();
1355
Owen Andersond184c182007-06-11 16:25:17 +00001356 if (BB == 0)
1357 continue;
1358
Owen Andersone02da552007-06-28 00:34:34 +00001359 SmallPtrSet<Value*, 16>& new_set = new_sets[BB];
1360 SmallPtrSet<Value*, 16>& availOut = availableOut[BB];
1361 SmallPtrSet<Value*, 16>& anticIn = anticipatedIn[BB];
Owen Andersonbe802402007-06-08 01:03:01 +00001362
Owen Anderson55994f22007-06-08 20:44:02 +00001363 new_set.clear();
1364
Owen Andersonbe802402007-06-08 01:03:01 +00001365 // Replace leaders with leaders inherited from dominator
1366 if (DI->getIDom() != 0) {
Owen Andersone02da552007-06-28 00:34:34 +00001367 SmallPtrSet<Value*, 16>& dom_set = new_sets[DI->getIDom()->getBlock()];
1368 for (SmallPtrSet<Value*, 16>::iterator I = dom_set.begin(),
Owen Andersonbe802402007-06-08 01:03:01 +00001369 E = dom_set.end(); I != E; ++I) {
1370 new_set.insert(*I);
Owen Andersonb56fba02007-06-19 03:31:41 +00001371 val_replace(availOut, *I);
Owen Andersonbe802402007-06-08 01:03:01 +00001372 }
1373 }
1374
1375 // If there is more than one predecessor...
1376 if (pred_begin(BB) != pred_end(BB) && ++pred_begin(BB) != pred_end(BB)) {
1377 std::vector<Value*> workList;
Owen Andersond50a29d2007-06-22 00:43:22 +00001378 workList.reserve(anticIn.size());
Owen Andersonbe802402007-06-08 01:03:01 +00001379 topo_sort(anticIn, workList);
1380
Owen Anderson06c1e582007-06-20 22:10:02 +00001381 unsigned result = insertion_mergepoint(workList, DI, new_set);
1382 if (result & 1)
1383 changed_function = true;
1384 if (result & 2)
1385 new_stuff = true;
Owen Andersonbe802402007-06-08 01:03:01 +00001386 }
1387 }
Owen Andersonbe802402007-06-08 01:03:01 +00001388 }
Owen Anderson634a0632007-06-06 01:27:49 +00001389
Owen Anderson06c1e582007-06-20 22:10:02 +00001390 return changed_function;
1391}
1392
Owen Andersonfd5683a2007-06-21 00:19:05 +00001393// GVNPRE::runOnFunction - This is the main transformation entry point for a
1394// function.
1395//
Owen Anderson06c1e582007-06-20 22:10:02 +00001396bool GVNPRE::runOnFunction(Function &F) {
Owen Andersonfd5683a2007-06-21 00:19:05 +00001397 // Clean out global sets from any previous functions
Owen Anderson06c1e582007-06-20 22:10:02 +00001398 VN.clear();
1399 createdExpressions.clear();
1400 availableOut.clear();
1401 anticipatedIn.clear();
1402
1403 bool changed_function = false;
1404
1405 // Phase 1: BuildSets
Owen Andersonfd5683a2007-06-21 00:19:05 +00001406 // This phase calculates the AVAIL_OUT and ANTIC_IN sets
Owen Anderson5477c542007-06-26 23:29:41 +00001407 buildsets(F);
Owen Anderson06c1e582007-06-20 22:10:02 +00001408
Owen Anderson7dae8ef2007-06-27 17:38:29 +00001409 for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI) {
Owen Anderson8a9fa5d2007-06-28 23:51:21 +00001410 DOUT << "AVAIL_OUT: " << FI->getName() << "\n";
1411 dump(availableOut[FI]);
1412 DOUT << "\n";
Owen Anderson7dae8ef2007-06-27 17:38:29 +00001413 DOUT << "ANTIC_IN: " << FI->getName() << "\n";
1414 dump(anticipatedIn[FI]);
1415 DOUT << "\n\n";
1416 }
1417
Owen Anderson06c1e582007-06-20 22:10:02 +00001418 // Phase 2: Insert
Owen Andersonfd5683a2007-06-21 00:19:05 +00001419 // This phase inserts values to make partially redundant values
1420 // fully redundant
Owen Anderson06c1e582007-06-20 22:10:02 +00001421 changed_function |= insertion(F);
1422
Owen Anderson634a0632007-06-06 01:27:49 +00001423 // Phase 3: Eliminate
Owen Andersonfd5683a2007-06-21 00:19:05 +00001424 // This phase performs trivial full redundancy elimination
Owen Anderson06c1e582007-06-20 22:10:02 +00001425 changed_function |= elimination();
Owen Anderson55994f22007-06-08 20:44:02 +00001426
Owen Andersonbe802402007-06-08 01:03:01 +00001427 // Phase 4: Cleanup
Owen Andersonfd5683a2007-06-21 00:19:05 +00001428 // This phase cleans up values that were created solely
1429 // as leaders for expressions
Owen Anderson42769842007-06-12 16:57:50 +00001430 cleanup();
Owen Andersonbe802402007-06-08 01:03:01 +00001431
Owen Andersonb0714bb2007-06-20 18:30:20 +00001432 return changed_function;
Owen Anderson5fba6c12007-05-29 21:53:49 +00001433}