Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 1 | //===- GVN.cpp - Eliminate redundant values and loads ------------===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
Chris Lattner | 4ee451d | 2007-12-29 20:36:04 +0000 | [diff] [blame] | 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // This pass performs global value numbering to eliminate fully redundant |
| 11 | // instructions. It also performs simple dead load elimination. |
| 12 | // |
| 13 | //===----------------------------------------------------------------------===// |
| 14 | |
| 15 | #define DEBUG_TYPE "gvn" |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 16 | #include "llvm/Transforms/Scalar.h" |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 17 | #include "llvm/BasicBlock.h" |
Owen Anderson | 4553791 | 2007-07-26 18:26:51 +0000 | [diff] [blame] | 18 | #include "llvm/Constants.h" |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 19 | #include "llvm/DerivedTypes.h" |
Owen Anderson | 4553791 | 2007-07-26 18:26:51 +0000 | [diff] [blame] | 20 | #include "llvm/Function.h" |
Owen Anderson | 30b4bd4 | 2008-02-12 21:15:18 +0000 | [diff] [blame] | 21 | #include "llvm/IntrinsicInst.h" |
Owen Anderson | 4553791 | 2007-07-26 18:26:51 +0000 | [diff] [blame] | 22 | #include "llvm/Instructions.h" |
Owen Anderson | 5aa4f2a | 2008-02-18 09:24:53 +0000 | [diff] [blame] | 23 | #include "llvm/ParameterAttributes.h" |
Owen Anderson | 4553791 | 2007-07-26 18:26:51 +0000 | [diff] [blame] | 24 | #include "llvm/Value.h" |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 25 | #include "llvm/ADT/BitVector.h" |
| 26 | #include "llvm/ADT/DenseMap.h" |
| 27 | #include "llvm/ADT/DepthFirstIterator.h" |
| 28 | #include "llvm/ADT/SmallPtrSet.h" |
| 29 | #include "llvm/ADT/SmallVector.h" |
| 30 | #include "llvm/ADT/Statistic.h" |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 31 | #include "llvm/Analysis/Dominators.h" |
| 32 | #include "llvm/Analysis/AliasAnalysis.h" |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 33 | #include "llvm/Analysis/MemoryDependenceAnalysis.h" |
| 34 | #include "llvm/Support/CFG.h" |
Evan Cheng | 88ffddd | 2008-03-24 05:28:38 +0000 | [diff] [blame] | 35 | #include "llvm/Support/CommandLine.h" |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 36 | #include "llvm/Support/Compiler.h" |
Chris Lattner | 9f8a6a7 | 2008-03-29 04:36:18 +0000 | [diff] [blame] | 37 | #include "llvm/Support/Debug.h" |
Chris Lattner | b017c9e | 2008-03-22 05:37:16 +0000 | [diff] [blame] | 38 | #include "llvm/Support/GetElementPtrTypeIterator.h" |
Owen Anderson | 61c24e9 | 2008-02-19 06:35:43 +0000 | [diff] [blame] | 39 | #include "llvm/Target/TargetData.h" |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 40 | #include <list> |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 41 | using namespace llvm; |
| 42 | |
Chris Lattner | d27290d | 2008-03-22 04:13:49 +0000 | [diff] [blame] | 43 | STATISTIC(NumGVNInstr, "Number of instructions deleted"); |
| 44 | STATISTIC(NumGVNLoad, "Number of loads deleted"); |
| 45 | STATISTIC(NumMemSetInfer, "Number of memsets inferred"); |
| 46 | |
Evan Cheng | 88ffddd | 2008-03-24 05:28:38 +0000 | [diff] [blame] | 47 | namespace { |
| 48 | cl::opt<bool> |
| 49 | FormMemSet("form-memset-from-stores", |
| 50 | cl::desc("Transform straight-line stores to memsets"), |
Chris Lattner | 9f8a6a7 | 2008-03-29 04:36:18 +0000 | [diff] [blame] | 51 | cl::init(true), cl::Hidden); |
Evan Cheng | 88ffddd | 2008-03-24 05:28:38 +0000 | [diff] [blame] | 52 | } |
Chris Lattner | d27290d | 2008-03-22 04:13:49 +0000 | [diff] [blame] | 53 | |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 54 | //===----------------------------------------------------------------------===// |
| 55 | // ValueTable Class |
| 56 | //===----------------------------------------------------------------------===// |
| 57 | |
| 58 | /// This class holds the mapping between values and value numbers. It is used |
| 59 | /// as an efficient mechanism to determine the expression-wise equivalence of |
| 60 | /// two values. |
| 61 | namespace { |
| 62 | struct VISIBILITY_HIDDEN Expression { |
| 63 | enum ExpressionOpcode { ADD, SUB, MUL, UDIV, SDIV, FDIV, UREM, SREM, |
| 64 | FREM, SHL, LSHR, ASHR, AND, OR, XOR, ICMPEQ, |
| 65 | ICMPNE, ICMPUGT, ICMPUGE, ICMPULT, ICMPULE, |
| 66 | ICMPSGT, ICMPSGE, ICMPSLT, ICMPSLE, FCMPOEQ, |
| 67 | FCMPOGT, FCMPOGE, FCMPOLT, FCMPOLE, FCMPONE, |
| 68 | FCMPORD, FCMPUNO, FCMPUEQ, FCMPUGT, FCMPUGE, |
| 69 | FCMPULT, FCMPULE, FCMPUNE, EXTRACT, INSERT, |
| 70 | SHUFFLE, SELECT, TRUNC, ZEXT, SEXT, FPTOUI, |
| 71 | FPTOSI, UITOFP, SITOFP, FPTRUNC, FPEXT, |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 72 | PTRTOINT, INTTOPTR, BITCAST, GEP, CALL, EMPTY, |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 73 | TOMBSTONE }; |
| 74 | |
| 75 | ExpressionOpcode opcode; |
| 76 | const Type* type; |
| 77 | uint32_t firstVN; |
| 78 | uint32_t secondVN; |
| 79 | uint32_t thirdVN; |
| 80 | SmallVector<uint32_t, 4> varargs; |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 81 | Value* function; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 82 | |
| 83 | Expression() { } |
| 84 | Expression(ExpressionOpcode o) : opcode(o) { } |
| 85 | |
| 86 | bool operator==(const Expression &other) const { |
| 87 | if (opcode != other.opcode) |
| 88 | return false; |
| 89 | else if (opcode == EMPTY || opcode == TOMBSTONE) |
| 90 | return true; |
| 91 | else if (type != other.type) |
| 92 | return false; |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 93 | else if (function != other.function) |
| 94 | return false; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 95 | else if (firstVN != other.firstVN) |
| 96 | return false; |
| 97 | else if (secondVN != other.secondVN) |
| 98 | return false; |
| 99 | else if (thirdVN != other.thirdVN) |
| 100 | return false; |
| 101 | else { |
| 102 | if (varargs.size() != other.varargs.size()) |
| 103 | return false; |
| 104 | |
| 105 | for (size_t i = 0; i < varargs.size(); ++i) |
| 106 | if (varargs[i] != other.varargs[i]) |
| 107 | return false; |
| 108 | |
| 109 | return true; |
| 110 | } |
| 111 | } |
| 112 | |
| 113 | bool operator!=(const Expression &other) const { |
| 114 | if (opcode != other.opcode) |
| 115 | return true; |
| 116 | else if (opcode == EMPTY || opcode == TOMBSTONE) |
| 117 | return false; |
| 118 | else if (type != other.type) |
| 119 | return true; |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 120 | else if (function != other.function) |
| 121 | return true; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 122 | else if (firstVN != other.firstVN) |
| 123 | return true; |
| 124 | else if (secondVN != other.secondVN) |
| 125 | return true; |
| 126 | else if (thirdVN != other.thirdVN) |
| 127 | return true; |
| 128 | else { |
| 129 | if (varargs.size() != other.varargs.size()) |
| 130 | return true; |
| 131 | |
| 132 | for (size_t i = 0; i < varargs.size(); ++i) |
| 133 | if (varargs[i] != other.varargs[i]) |
| 134 | return true; |
| 135 | |
| 136 | return false; |
| 137 | } |
| 138 | } |
| 139 | }; |
| 140 | |
| 141 | class VISIBILITY_HIDDEN ValueTable { |
| 142 | private: |
| 143 | DenseMap<Value*, uint32_t> valueNumbering; |
| 144 | DenseMap<Expression, uint32_t> expressionNumbering; |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 145 | AliasAnalysis* AA; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 146 | |
| 147 | uint32_t nextValueNumber; |
| 148 | |
| 149 | Expression::ExpressionOpcode getOpcode(BinaryOperator* BO); |
| 150 | Expression::ExpressionOpcode getOpcode(CmpInst* C); |
| 151 | Expression::ExpressionOpcode getOpcode(CastInst* C); |
| 152 | Expression create_expression(BinaryOperator* BO); |
| 153 | Expression create_expression(CmpInst* C); |
| 154 | Expression create_expression(ShuffleVectorInst* V); |
| 155 | Expression create_expression(ExtractElementInst* C); |
| 156 | Expression create_expression(InsertElementInst* V); |
| 157 | Expression create_expression(SelectInst* V); |
| 158 | Expression create_expression(CastInst* C); |
| 159 | Expression create_expression(GetElementPtrInst* G); |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 160 | Expression create_expression(CallInst* C); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 161 | public: |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 162 | ValueTable() : nextValueNumber(1) { } |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 163 | uint32_t lookup_or_add(Value* V); |
| 164 | uint32_t lookup(Value* V) const; |
| 165 | void add(Value* V, uint32_t num); |
| 166 | void clear(); |
| 167 | void erase(Value* v); |
| 168 | unsigned size(); |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 169 | void setAliasAnalysis(AliasAnalysis* A) { AA = A; } |
Owen Anderson | a16bbc9a | 2007-11-26 07:17:19 +0000 | [diff] [blame] | 170 | uint32_t hash_operand(Value* v); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 171 | }; |
| 172 | } |
| 173 | |
| 174 | namespace llvm { |
Chris Lattner | 76c1b97 | 2007-09-17 18:34:04 +0000 | [diff] [blame] | 175 | template <> struct DenseMapInfo<Expression> { |
Owen Anderson | 830db6a | 2007-08-02 18:16:06 +0000 | [diff] [blame] | 176 | static inline Expression getEmptyKey() { |
| 177 | return Expression(Expression::EMPTY); |
| 178 | } |
| 179 | |
| 180 | static inline Expression getTombstoneKey() { |
| 181 | return Expression(Expression::TOMBSTONE); |
| 182 | } |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 183 | |
| 184 | static unsigned getHashValue(const Expression e) { |
| 185 | unsigned hash = e.opcode; |
| 186 | |
| 187 | hash = e.firstVN + hash * 37; |
| 188 | hash = e.secondVN + hash * 37; |
| 189 | hash = e.thirdVN + hash * 37; |
| 190 | |
Anton Korobeynikov | 07e6e56 | 2008-02-20 11:26:25 +0000 | [diff] [blame] | 191 | hash = ((unsigned)((uintptr_t)e.type >> 4) ^ |
| 192 | (unsigned)((uintptr_t)e.type >> 9)) + |
| 193 | hash * 37; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 194 | |
Owen Anderson | 830db6a | 2007-08-02 18:16:06 +0000 | [diff] [blame] | 195 | for (SmallVector<uint32_t, 4>::const_iterator I = e.varargs.begin(), |
| 196 | E = e.varargs.end(); I != E; ++I) |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 197 | hash = *I + hash * 37; |
| 198 | |
Anton Korobeynikov | 07e6e56 | 2008-02-20 11:26:25 +0000 | [diff] [blame] | 199 | hash = ((unsigned)((uintptr_t)e.function >> 4) ^ |
| 200 | (unsigned)((uintptr_t)e.function >> 9)) + |
| 201 | hash * 37; |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 202 | |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 203 | return hash; |
| 204 | } |
Chris Lattner | 76c1b97 | 2007-09-17 18:34:04 +0000 | [diff] [blame] | 205 | static bool isEqual(const Expression &LHS, const Expression &RHS) { |
| 206 | return LHS == RHS; |
| 207 | } |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 208 | static bool isPod() { return true; } |
| 209 | }; |
| 210 | } |
| 211 | |
| 212 | //===----------------------------------------------------------------------===// |
| 213 | // ValueTable Internal Functions |
| 214 | //===----------------------------------------------------------------------===// |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 215 | Expression::ExpressionOpcode ValueTable::getOpcode(BinaryOperator* BO) { |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 216 | switch(BO->getOpcode()) { |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 217 | default: // THIS SHOULD NEVER HAPPEN |
| 218 | assert(0 && "Binary operator with unknown opcode?"); |
| 219 | case Instruction::Add: return Expression::ADD; |
| 220 | case Instruction::Sub: return Expression::SUB; |
| 221 | case Instruction::Mul: return Expression::MUL; |
| 222 | case Instruction::UDiv: return Expression::UDIV; |
| 223 | case Instruction::SDiv: return Expression::SDIV; |
| 224 | case Instruction::FDiv: return Expression::FDIV; |
| 225 | case Instruction::URem: return Expression::UREM; |
| 226 | case Instruction::SRem: return Expression::SREM; |
| 227 | case Instruction::FRem: return Expression::FREM; |
| 228 | case Instruction::Shl: return Expression::SHL; |
| 229 | case Instruction::LShr: return Expression::LSHR; |
| 230 | case Instruction::AShr: return Expression::ASHR; |
| 231 | case Instruction::And: return Expression::AND; |
| 232 | case Instruction::Or: return Expression::OR; |
| 233 | case Instruction::Xor: return Expression::XOR; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 234 | } |
| 235 | } |
| 236 | |
| 237 | Expression::ExpressionOpcode ValueTable::getOpcode(CmpInst* C) { |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 238 | if (isa<ICmpInst>(C)) { |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 239 | switch (C->getPredicate()) { |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 240 | default: // THIS SHOULD NEVER HAPPEN |
| 241 | assert(0 && "Comparison with unknown predicate?"); |
| 242 | case ICmpInst::ICMP_EQ: return Expression::ICMPEQ; |
| 243 | case ICmpInst::ICMP_NE: return Expression::ICMPNE; |
| 244 | case ICmpInst::ICMP_UGT: return Expression::ICMPUGT; |
| 245 | case ICmpInst::ICMP_UGE: return Expression::ICMPUGE; |
| 246 | case ICmpInst::ICMP_ULT: return Expression::ICMPULT; |
| 247 | case ICmpInst::ICMP_ULE: return Expression::ICMPULE; |
| 248 | case ICmpInst::ICMP_SGT: return Expression::ICMPSGT; |
| 249 | case ICmpInst::ICMP_SGE: return Expression::ICMPSGE; |
| 250 | case ICmpInst::ICMP_SLT: return Expression::ICMPSLT; |
| 251 | case ICmpInst::ICMP_SLE: return Expression::ICMPSLE; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 252 | } |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 253 | } |
| 254 | assert(isa<FCmpInst>(C) && "Unknown compare"); |
| 255 | switch (C->getPredicate()) { |
| 256 | default: // THIS SHOULD NEVER HAPPEN |
| 257 | assert(0 && "Comparison with unknown predicate?"); |
| 258 | case FCmpInst::FCMP_OEQ: return Expression::FCMPOEQ; |
| 259 | case FCmpInst::FCMP_OGT: return Expression::FCMPOGT; |
| 260 | case FCmpInst::FCMP_OGE: return Expression::FCMPOGE; |
| 261 | case FCmpInst::FCMP_OLT: return Expression::FCMPOLT; |
| 262 | case FCmpInst::FCMP_OLE: return Expression::FCMPOLE; |
| 263 | case FCmpInst::FCMP_ONE: return Expression::FCMPONE; |
| 264 | case FCmpInst::FCMP_ORD: return Expression::FCMPORD; |
| 265 | case FCmpInst::FCMP_UNO: return Expression::FCMPUNO; |
| 266 | case FCmpInst::FCMP_UEQ: return Expression::FCMPUEQ; |
| 267 | case FCmpInst::FCMP_UGT: return Expression::FCMPUGT; |
| 268 | case FCmpInst::FCMP_UGE: return Expression::FCMPUGE; |
| 269 | case FCmpInst::FCMP_ULT: return Expression::FCMPULT; |
| 270 | case FCmpInst::FCMP_ULE: return Expression::FCMPULE; |
| 271 | case FCmpInst::FCMP_UNE: return Expression::FCMPUNE; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 272 | } |
| 273 | } |
| 274 | |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 275 | Expression::ExpressionOpcode ValueTable::getOpcode(CastInst* C) { |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 276 | switch(C->getOpcode()) { |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 277 | default: // THIS SHOULD NEVER HAPPEN |
| 278 | assert(0 && "Cast operator with unknown opcode?"); |
| 279 | case Instruction::Trunc: return Expression::TRUNC; |
| 280 | case Instruction::ZExt: return Expression::ZEXT; |
| 281 | case Instruction::SExt: return Expression::SEXT; |
| 282 | case Instruction::FPToUI: return Expression::FPTOUI; |
| 283 | case Instruction::FPToSI: return Expression::FPTOSI; |
| 284 | case Instruction::UIToFP: return Expression::UITOFP; |
| 285 | case Instruction::SIToFP: return Expression::SITOFP; |
| 286 | case Instruction::FPTrunc: return Expression::FPTRUNC; |
| 287 | case Instruction::FPExt: return Expression::FPEXT; |
| 288 | case Instruction::PtrToInt: return Expression::PTRTOINT; |
| 289 | case Instruction::IntToPtr: return Expression::INTTOPTR; |
| 290 | case Instruction::BitCast: return Expression::BITCAST; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 291 | } |
| 292 | } |
| 293 | |
Owen Anderson | a16bbc9a | 2007-11-26 07:17:19 +0000 | [diff] [blame] | 294 | uint32_t ValueTable::hash_operand(Value* v) { |
| 295 | if (CallInst* CI = dyn_cast<CallInst>(v)) |
Duncan Sands | dff6710 | 2007-12-01 07:51:45 +0000 | [diff] [blame] | 296 | if (!AA->doesNotAccessMemory(CI)) |
Owen Anderson | a16bbc9a | 2007-11-26 07:17:19 +0000 | [diff] [blame] | 297 | return nextValueNumber++; |
| 298 | |
| 299 | return lookup_or_add(v); |
| 300 | } |
| 301 | |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 302 | Expression ValueTable::create_expression(CallInst* C) { |
| 303 | Expression e; |
| 304 | |
| 305 | e.type = C->getType(); |
| 306 | e.firstVN = 0; |
| 307 | e.secondVN = 0; |
| 308 | e.thirdVN = 0; |
| 309 | e.function = C->getCalledFunction(); |
| 310 | e.opcode = Expression::CALL; |
| 311 | |
| 312 | for (CallInst::op_iterator I = C->op_begin()+1, E = C->op_end(); |
| 313 | I != E; ++I) |
Owen Anderson | a16bbc9a | 2007-11-26 07:17:19 +0000 | [diff] [blame] | 314 | e.varargs.push_back(hash_operand(*I)); |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 315 | |
| 316 | return e; |
| 317 | } |
| 318 | |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 319 | Expression ValueTable::create_expression(BinaryOperator* BO) { |
| 320 | Expression e; |
| 321 | |
Owen Anderson | a16bbc9a | 2007-11-26 07:17:19 +0000 | [diff] [blame] | 322 | e.firstVN = hash_operand(BO->getOperand(0)); |
| 323 | e.secondVN = hash_operand(BO->getOperand(1)); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 324 | e.thirdVN = 0; |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 325 | e.function = 0; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 326 | e.type = BO->getType(); |
| 327 | e.opcode = getOpcode(BO); |
| 328 | |
| 329 | return e; |
| 330 | } |
| 331 | |
| 332 | Expression ValueTable::create_expression(CmpInst* C) { |
| 333 | Expression e; |
| 334 | |
Owen Anderson | a16bbc9a | 2007-11-26 07:17:19 +0000 | [diff] [blame] | 335 | e.firstVN = hash_operand(C->getOperand(0)); |
| 336 | e.secondVN = hash_operand(C->getOperand(1)); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 337 | e.thirdVN = 0; |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 338 | e.function = 0; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 339 | e.type = C->getType(); |
| 340 | e.opcode = getOpcode(C); |
| 341 | |
| 342 | return e; |
| 343 | } |
| 344 | |
| 345 | Expression ValueTable::create_expression(CastInst* C) { |
| 346 | Expression e; |
| 347 | |
Owen Anderson | a16bbc9a | 2007-11-26 07:17:19 +0000 | [diff] [blame] | 348 | e.firstVN = hash_operand(C->getOperand(0)); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 349 | e.secondVN = 0; |
| 350 | e.thirdVN = 0; |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 351 | e.function = 0; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 352 | e.type = C->getType(); |
| 353 | e.opcode = getOpcode(C); |
| 354 | |
| 355 | return e; |
| 356 | } |
| 357 | |
| 358 | Expression ValueTable::create_expression(ShuffleVectorInst* S) { |
| 359 | Expression e; |
| 360 | |
Owen Anderson | a16bbc9a | 2007-11-26 07:17:19 +0000 | [diff] [blame] | 361 | e.firstVN = hash_operand(S->getOperand(0)); |
| 362 | e.secondVN = hash_operand(S->getOperand(1)); |
| 363 | e.thirdVN = hash_operand(S->getOperand(2)); |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 364 | e.function = 0; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 365 | e.type = S->getType(); |
| 366 | e.opcode = Expression::SHUFFLE; |
| 367 | |
| 368 | return e; |
| 369 | } |
| 370 | |
| 371 | Expression ValueTable::create_expression(ExtractElementInst* E) { |
| 372 | Expression e; |
| 373 | |
Owen Anderson | a16bbc9a | 2007-11-26 07:17:19 +0000 | [diff] [blame] | 374 | e.firstVN = hash_operand(E->getOperand(0)); |
| 375 | e.secondVN = hash_operand(E->getOperand(1)); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 376 | e.thirdVN = 0; |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 377 | e.function = 0; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 378 | e.type = E->getType(); |
| 379 | e.opcode = Expression::EXTRACT; |
| 380 | |
| 381 | return e; |
| 382 | } |
| 383 | |
| 384 | Expression ValueTable::create_expression(InsertElementInst* I) { |
| 385 | Expression e; |
| 386 | |
Owen Anderson | a16bbc9a | 2007-11-26 07:17:19 +0000 | [diff] [blame] | 387 | e.firstVN = hash_operand(I->getOperand(0)); |
| 388 | e.secondVN = hash_operand(I->getOperand(1)); |
| 389 | e.thirdVN = hash_operand(I->getOperand(2)); |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 390 | e.function = 0; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 391 | e.type = I->getType(); |
| 392 | e.opcode = Expression::INSERT; |
| 393 | |
| 394 | return e; |
| 395 | } |
| 396 | |
| 397 | Expression ValueTable::create_expression(SelectInst* I) { |
| 398 | Expression e; |
| 399 | |
Owen Anderson | a16bbc9a | 2007-11-26 07:17:19 +0000 | [diff] [blame] | 400 | e.firstVN = hash_operand(I->getCondition()); |
| 401 | e.secondVN = hash_operand(I->getTrueValue()); |
| 402 | e.thirdVN = hash_operand(I->getFalseValue()); |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 403 | e.function = 0; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 404 | e.type = I->getType(); |
| 405 | e.opcode = Expression::SELECT; |
| 406 | |
| 407 | return e; |
| 408 | } |
| 409 | |
| 410 | Expression ValueTable::create_expression(GetElementPtrInst* G) { |
| 411 | Expression e; |
| 412 | |
Owen Anderson | a16bbc9a | 2007-11-26 07:17:19 +0000 | [diff] [blame] | 413 | e.firstVN = hash_operand(G->getPointerOperand()); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 414 | e.secondVN = 0; |
| 415 | e.thirdVN = 0; |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 416 | e.function = 0; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 417 | e.type = G->getType(); |
| 418 | e.opcode = Expression::GEP; |
| 419 | |
| 420 | for (GetElementPtrInst::op_iterator I = G->idx_begin(), E = G->idx_end(); |
| 421 | I != E; ++I) |
Owen Anderson | a16bbc9a | 2007-11-26 07:17:19 +0000 | [diff] [blame] | 422 | e.varargs.push_back(hash_operand(*I)); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 423 | |
| 424 | return e; |
| 425 | } |
| 426 | |
| 427 | //===----------------------------------------------------------------------===// |
| 428 | // ValueTable External Functions |
| 429 | //===----------------------------------------------------------------------===// |
| 430 | |
| 431 | /// lookup_or_add - Returns the value number for the specified value, assigning |
| 432 | /// it a new number if it did not have one before. |
| 433 | uint32_t ValueTable::lookup_or_add(Value* V) { |
| 434 | DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V); |
| 435 | if (VI != valueNumbering.end()) |
| 436 | return VI->second; |
| 437 | |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 438 | if (CallInst* C = dyn_cast<CallInst>(V)) { |
Duncan Sands | dff6710 | 2007-12-01 07:51:45 +0000 | [diff] [blame] | 439 | if (AA->onlyReadsMemory(C)) { // includes doesNotAccessMemory |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 440 | Expression e = create_expression(C); |
| 441 | |
| 442 | DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e); |
| 443 | if (EI != expressionNumbering.end()) { |
| 444 | valueNumbering.insert(std::make_pair(V, EI->second)); |
| 445 | return EI->second; |
| 446 | } else { |
| 447 | expressionNumbering.insert(std::make_pair(e, nextValueNumber)); |
| 448 | valueNumbering.insert(std::make_pair(V, nextValueNumber)); |
| 449 | |
| 450 | return nextValueNumber++; |
| 451 | } |
| 452 | } else { |
| 453 | valueNumbering.insert(std::make_pair(V, nextValueNumber)); |
| 454 | return nextValueNumber++; |
| 455 | } |
| 456 | } else if (BinaryOperator* BO = dyn_cast<BinaryOperator>(V)) { |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 457 | Expression e = create_expression(BO); |
| 458 | |
| 459 | DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e); |
| 460 | if (EI != expressionNumbering.end()) { |
| 461 | valueNumbering.insert(std::make_pair(V, EI->second)); |
| 462 | return EI->second; |
| 463 | } else { |
| 464 | expressionNumbering.insert(std::make_pair(e, nextValueNumber)); |
| 465 | valueNumbering.insert(std::make_pair(V, nextValueNumber)); |
| 466 | |
| 467 | return nextValueNumber++; |
| 468 | } |
| 469 | } else if (CmpInst* C = dyn_cast<CmpInst>(V)) { |
| 470 | Expression e = create_expression(C); |
| 471 | |
| 472 | DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e); |
| 473 | if (EI != expressionNumbering.end()) { |
| 474 | valueNumbering.insert(std::make_pair(V, EI->second)); |
| 475 | return EI->second; |
| 476 | } else { |
| 477 | expressionNumbering.insert(std::make_pair(e, nextValueNumber)); |
| 478 | valueNumbering.insert(std::make_pair(V, nextValueNumber)); |
| 479 | |
| 480 | return nextValueNumber++; |
| 481 | } |
| 482 | } else if (ShuffleVectorInst* U = dyn_cast<ShuffleVectorInst>(V)) { |
| 483 | Expression e = create_expression(U); |
| 484 | |
| 485 | DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e); |
| 486 | if (EI != expressionNumbering.end()) { |
| 487 | valueNumbering.insert(std::make_pair(V, EI->second)); |
| 488 | return EI->second; |
| 489 | } else { |
| 490 | expressionNumbering.insert(std::make_pair(e, nextValueNumber)); |
| 491 | valueNumbering.insert(std::make_pair(V, nextValueNumber)); |
| 492 | |
| 493 | return nextValueNumber++; |
| 494 | } |
| 495 | } else if (ExtractElementInst* U = dyn_cast<ExtractElementInst>(V)) { |
| 496 | Expression e = create_expression(U); |
| 497 | |
| 498 | DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e); |
| 499 | if (EI != expressionNumbering.end()) { |
| 500 | valueNumbering.insert(std::make_pair(V, EI->second)); |
| 501 | return EI->second; |
| 502 | } else { |
| 503 | expressionNumbering.insert(std::make_pair(e, nextValueNumber)); |
| 504 | valueNumbering.insert(std::make_pair(V, nextValueNumber)); |
| 505 | |
| 506 | return nextValueNumber++; |
| 507 | } |
| 508 | } else if (InsertElementInst* U = dyn_cast<InsertElementInst>(V)) { |
| 509 | Expression e = create_expression(U); |
| 510 | |
| 511 | DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e); |
| 512 | if (EI != expressionNumbering.end()) { |
| 513 | valueNumbering.insert(std::make_pair(V, EI->second)); |
| 514 | return EI->second; |
| 515 | } else { |
| 516 | expressionNumbering.insert(std::make_pair(e, nextValueNumber)); |
| 517 | valueNumbering.insert(std::make_pair(V, nextValueNumber)); |
| 518 | |
| 519 | return nextValueNumber++; |
| 520 | } |
| 521 | } else if (SelectInst* U = dyn_cast<SelectInst>(V)) { |
| 522 | Expression e = create_expression(U); |
| 523 | |
| 524 | DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e); |
| 525 | if (EI != expressionNumbering.end()) { |
| 526 | valueNumbering.insert(std::make_pair(V, EI->second)); |
| 527 | return EI->second; |
| 528 | } else { |
| 529 | expressionNumbering.insert(std::make_pair(e, nextValueNumber)); |
| 530 | valueNumbering.insert(std::make_pair(V, nextValueNumber)); |
| 531 | |
| 532 | return nextValueNumber++; |
| 533 | } |
| 534 | } else if (CastInst* U = dyn_cast<CastInst>(V)) { |
| 535 | Expression e = create_expression(U); |
| 536 | |
| 537 | DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e); |
| 538 | if (EI != expressionNumbering.end()) { |
| 539 | valueNumbering.insert(std::make_pair(V, EI->second)); |
| 540 | return EI->second; |
| 541 | } else { |
| 542 | expressionNumbering.insert(std::make_pair(e, nextValueNumber)); |
| 543 | valueNumbering.insert(std::make_pair(V, nextValueNumber)); |
| 544 | |
| 545 | return nextValueNumber++; |
| 546 | } |
| 547 | } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(V)) { |
| 548 | Expression e = create_expression(U); |
| 549 | |
| 550 | DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e); |
| 551 | if (EI != expressionNumbering.end()) { |
| 552 | valueNumbering.insert(std::make_pair(V, EI->second)); |
| 553 | return EI->second; |
| 554 | } else { |
| 555 | expressionNumbering.insert(std::make_pair(e, nextValueNumber)); |
| 556 | valueNumbering.insert(std::make_pair(V, nextValueNumber)); |
| 557 | |
| 558 | return nextValueNumber++; |
| 559 | } |
| 560 | } else { |
| 561 | valueNumbering.insert(std::make_pair(V, nextValueNumber)); |
| 562 | return nextValueNumber++; |
| 563 | } |
| 564 | } |
| 565 | |
| 566 | /// lookup - Returns the value number of the specified value. Fails if |
| 567 | /// the value has not yet been numbered. |
| 568 | uint32_t ValueTable::lookup(Value* V) const { |
| 569 | DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V); |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 570 | assert(VI != valueNumbering.end() && "Value not numbered?"); |
| 571 | return VI->second; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 572 | } |
| 573 | |
| 574 | /// clear - Remove all entries from the ValueTable |
| 575 | void ValueTable::clear() { |
| 576 | valueNumbering.clear(); |
| 577 | expressionNumbering.clear(); |
| 578 | nextValueNumber = 1; |
| 579 | } |
| 580 | |
Owen Anderson | bf7d0bc | 2007-07-31 23:27:13 +0000 | [diff] [blame] | 581 | /// erase - Remove a value from the value numbering |
| 582 | void ValueTable::erase(Value* V) { |
| 583 | valueNumbering.erase(V); |
| 584 | } |
| 585 | |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 586 | //===----------------------------------------------------------------------===// |
| 587 | // ValueNumberedSet Class |
| 588 | //===----------------------------------------------------------------------===// |
| 589 | namespace { |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 590 | class VISIBILITY_HIDDEN ValueNumberedSet { |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 591 | private: |
| 592 | SmallPtrSet<Value*, 8> contents; |
| 593 | BitVector numbers; |
| 594 | public: |
| 595 | ValueNumberedSet() { numbers.resize(1); } |
| 596 | ValueNumberedSet(const ValueNumberedSet& other) { |
| 597 | numbers = other.numbers; |
| 598 | contents = other.contents; |
| 599 | } |
| 600 | |
| 601 | typedef SmallPtrSet<Value*, 8>::iterator iterator; |
| 602 | |
| 603 | iterator begin() { return contents.begin(); } |
| 604 | iterator end() { return contents.end(); } |
| 605 | |
| 606 | bool insert(Value* v) { return contents.insert(v); } |
| 607 | void insert(iterator I, iterator E) { contents.insert(I, E); } |
| 608 | void erase(Value* v) { contents.erase(v); } |
| 609 | unsigned count(Value* v) { return contents.count(v); } |
| 610 | size_t size() { return contents.size(); } |
| 611 | |
| 612 | void set(unsigned i) { |
| 613 | if (i >= numbers.size()) |
| 614 | numbers.resize(i+1); |
| 615 | |
| 616 | numbers.set(i); |
| 617 | } |
| 618 | |
| 619 | void operator=(const ValueNumberedSet& other) { |
| 620 | contents = other.contents; |
| 621 | numbers = other.numbers; |
| 622 | } |
| 623 | |
| 624 | void reset(unsigned i) { |
| 625 | if (i < numbers.size()) |
| 626 | numbers.reset(i); |
| 627 | } |
| 628 | |
| 629 | bool test(unsigned i) { |
| 630 | if (i >= numbers.size()) |
| 631 | return false; |
| 632 | |
| 633 | return numbers.test(i); |
| 634 | } |
| 635 | |
| 636 | void clear() { |
| 637 | contents.clear(); |
| 638 | numbers.clear(); |
| 639 | } |
| 640 | }; |
| 641 | } |
| 642 | |
| 643 | //===----------------------------------------------------------------------===// |
| 644 | // GVN Pass |
| 645 | //===----------------------------------------------------------------------===// |
| 646 | |
| 647 | namespace { |
| 648 | |
| 649 | class VISIBILITY_HIDDEN GVN : public FunctionPass { |
| 650 | bool runOnFunction(Function &F); |
| 651 | public: |
| 652 | static char ID; // Pass identification, replacement for typeid |
| 653 | GVN() : FunctionPass((intptr_t)&ID) { } |
| 654 | |
| 655 | private: |
| 656 | ValueTable VN; |
| 657 | |
| 658 | DenseMap<BasicBlock*, ValueNumberedSet> availableOut; |
| 659 | |
Owen Anderson | a37226a | 2007-08-07 23:12:31 +0000 | [diff] [blame] | 660 | typedef DenseMap<Value*, SmallPtrSet<Instruction*, 4> > PhiMapType; |
| 661 | PhiMapType phiMap; |
| 662 | |
| 663 | |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 664 | // This transformation requires dominator postdominator info |
| 665 | virtual void getAnalysisUsage(AnalysisUsage &AU) const { |
| 666 | AU.setPreservesCFG(); |
| 667 | AU.addRequired<DominatorTree>(); |
| 668 | AU.addRequired<MemoryDependenceAnalysis>(); |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 669 | AU.addRequired<AliasAnalysis>(); |
Owen Anderson | 61c24e9 | 2008-02-19 06:35:43 +0000 | [diff] [blame] | 670 | AU.addRequired<TargetData>(); |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 671 | AU.addPreserved<AliasAnalysis>(); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 672 | AU.addPreserved<MemoryDependenceAnalysis>(); |
Owen Anderson | 61c24e9 | 2008-02-19 06:35:43 +0000 | [diff] [blame] | 673 | AU.addPreserved<TargetData>(); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 674 | } |
| 675 | |
| 676 | // Helper fuctions |
| 677 | // FIXME: eliminate or document these better |
| 678 | Value* find_leader(ValueNumberedSet& vals, uint32_t v) ; |
| 679 | void val_insert(ValueNumberedSet& s, Value* v); |
| 680 | bool processLoad(LoadInst* L, |
Chris Lattner | 8e1e95c | 2008-03-21 22:01:16 +0000 | [diff] [blame] | 681 | DenseMap<Value*, LoadInst*> &lastLoad, |
| 682 | SmallVectorImpl<Instruction*> &toErase); |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 683 | bool processStore(StoreInst *SI, SmallVectorImpl<Instruction*> &toErase); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 684 | bool processInstruction(Instruction* I, |
| 685 | ValueNumberedSet& currAvail, |
| 686 | DenseMap<Value*, LoadInst*>& lastSeenLoad, |
Chris Lattner | 8e1e95c | 2008-03-21 22:01:16 +0000 | [diff] [blame] | 687 | SmallVectorImpl<Instruction*> &toErase); |
Owen Anderson | 830db6a | 2007-08-02 18:16:06 +0000 | [diff] [blame] | 688 | bool processNonLocalLoad(LoadInst* L, |
Chris Lattner | 8e1e95c | 2008-03-21 22:01:16 +0000 | [diff] [blame] | 689 | SmallVectorImpl<Instruction*> &toErase); |
Owen Anderson | 7acc0af | 2008-02-19 03:09:45 +0000 | [diff] [blame] | 690 | bool processMemCpy(MemCpyInst* M, MemCpyInst* MDep, |
Chris Lattner | 8e1e95c | 2008-03-21 22:01:16 +0000 | [diff] [blame] | 691 | SmallVectorImpl<Instruction*> &toErase); |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 692 | bool performCallSlotOptzn(MemCpyInst* cpy, CallInst* C, |
Chris Lattner | 8e1e95c | 2008-03-21 22:01:16 +0000 | [diff] [blame] | 693 | SmallVectorImpl<Instruction*> &toErase); |
Owen Anderson | 4553791 | 2007-07-26 18:26:51 +0000 | [diff] [blame] | 694 | Value *GetValueForBlock(BasicBlock *BB, LoadInst* orig, |
Owen Anderson | 1c2763d | 2007-08-02 17:56:05 +0000 | [diff] [blame] | 695 | DenseMap<BasicBlock*, Value*> &Phis, |
| 696 | bool top_level = false); |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 697 | void dump(DenseMap<BasicBlock*, Value*>& d); |
Owen Anderson | 3e75a42 | 2007-08-14 18:04:11 +0000 | [diff] [blame] | 698 | bool iterateOnFunction(Function &F); |
Owen Anderson | 1defe2d | 2007-08-16 22:51:56 +0000 | [diff] [blame] | 699 | Value* CollapsePhi(PHINode* p); |
Owen Anderson | 2486686 | 2007-09-16 08:04:16 +0000 | [diff] [blame] | 700 | bool isSafeReplacement(PHINode* p, Instruction* inst); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 701 | }; |
| 702 | |
| 703 | char GVN::ID = 0; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 704 | } |
| 705 | |
| 706 | // createGVNPass - The public interface to this file... |
| 707 | FunctionPass *llvm::createGVNPass() { return new GVN(); } |
| 708 | |
| 709 | static RegisterPass<GVN> X("gvn", |
| 710 | "Global Value Numbering"); |
| 711 | |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 712 | /// find_leader - Given a set and a value number, return the first |
| 713 | /// element of the set with that value number, or 0 if no such element |
| 714 | /// is present |
| 715 | Value* GVN::find_leader(ValueNumberedSet& vals, uint32_t v) { |
| 716 | if (!vals.test(v)) |
| 717 | return 0; |
| 718 | |
| 719 | for (ValueNumberedSet::iterator I = vals.begin(), E = vals.end(); |
| 720 | I != E; ++I) |
| 721 | if (v == VN.lookup(*I)) |
| 722 | return *I; |
| 723 | |
| 724 | assert(0 && "No leader found, but present bit is set?"); |
| 725 | return 0; |
| 726 | } |
| 727 | |
| 728 | /// val_insert - Insert a value into a set only if there is not a value |
| 729 | /// with the same value number already in the set |
| 730 | void GVN::val_insert(ValueNumberedSet& s, Value* v) { |
| 731 | uint32_t num = VN.lookup(v); |
| 732 | if (!s.test(num)) |
| 733 | s.insert(v); |
| 734 | } |
| 735 | |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 736 | void GVN::dump(DenseMap<BasicBlock*, Value*>& d) { |
| 737 | printf("{\n"); |
| 738 | for (DenseMap<BasicBlock*, Value*>::iterator I = d.begin(), |
| 739 | E = d.end(); I != E; ++I) { |
| 740 | if (I->second == MemoryDependenceAnalysis::None) |
| 741 | printf("None\n"); |
| 742 | else |
| 743 | I->second->dump(); |
| 744 | } |
| 745 | printf("}\n"); |
| 746 | } |
| 747 | |
Owen Anderson | 1defe2d | 2007-08-16 22:51:56 +0000 | [diff] [blame] | 748 | Value* GVN::CollapsePhi(PHINode* p) { |
| 749 | DominatorTree &DT = getAnalysis<DominatorTree>(); |
| 750 | Value* constVal = p->hasConstantValue(); |
| 751 | |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 752 | if (!constVal) return 0; |
Owen Anderson | 1defe2d | 2007-08-16 22:51:56 +0000 | [diff] [blame] | 753 | |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 754 | Instruction* inst = dyn_cast<Instruction>(constVal); |
| 755 | if (!inst) |
| 756 | return constVal; |
| 757 | |
| 758 | if (DT.dominates(inst, p)) |
| 759 | if (isSafeReplacement(p, inst)) |
| 760 | return inst; |
Owen Anderson | 1defe2d | 2007-08-16 22:51:56 +0000 | [diff] [blame] | 761 | return 0; |
| 762 | } |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 763 | |
Owen Anderson | 2486686 | 2007-09-16 08:04:16 +0000 | [diff] [blame] | 764 | bool GVN::isSafeReplacement(PHINode* p, Instruction* inst) { |
| 765 | if (!isa<PHINode>(inst)) |
| 766 | return true; |
| 767 | |
| 768 | for (Instruction::use_iterator UI = p->use_begin(), E = p->use_end(); |
| 769 | UI != E; ++UI) |
| 770 | if (PHINode* use_phi = dyn_cast<PHINode>(UI)) |
| 771 | if (use_phi->getParent() == inst->getParent()) |
| 772 | return false; |
| 773 | |
| 774 | return true; |
| 775 | } |
| 776 | |
Owen Anderson | 4553791 | 2007-07-26 18:26:51 +0000 | [diff] [blame] | 777 | /// GetValueForBlock - Get the value to use within the specified basic block. |
| 778 | /// available values are in Phis. |
| 779 | Value *GVN::GetValueForBlock(BasicBlock *BB, LoadInst* orig, |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 780 | DenseMap<BasicBlock*, Value*> &Phis, |
| 781 | bool top_level) { |
Owen Anderson | 4553791 | 2007-07-26 18:26:51 +0000 | [diff] [blame] | 782 | |
| 783 | // If we have already computed this value, return the previously computed val. |
Owen Anderson | ab87027 | 2007-08-03 19:59:35 +0000 | [diff] [blame] | 784 | DenseMap<BasicBlock*, Value*>::iterator V = Phis.find(BB); |
| 785 | if (V != Phis.end() && !top_level) return V->second; |
Owen Anderson | 4553791 | 2007-07-26 18:26:51 +0000 | [diff] [blame] | 786 | |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 787 | BasicBlock* singlePred = BB->getSinglePredecessor(); |
Owen Anderson | 4b55c3b | 2007-08-03 11:03:26 +0000 | [diff] [blame] | 788 | if (singlePred) { |
Owen Anderson | ab87027 | 2007-08-03 19:59:35 +0000 | [diff] [blame] | 789 | Value *ret = GetValueForBlock(singlePred, orig, Phis); |
| 790 | Phis[BB] = ret; |
| 791 | return ret; |
Owen Anderson | 4b55c3b | 2007-08-03 11:03:26 +0000 | [diff] [blame] | 792 | } |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 793 | |
Owen Anderson | 4553791 | 2007-07-26 18:26:51 +0000 | [diff] [blame] | 794 | // Otherwise, the idom is the loop, so we need to insert a PHI node. Do so |
| 795 | // now, then get values to fill in the incoming values for the PHI. |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 796 | PHINode *PN = PHINode::Create(orig->getType(), orig->getName()+".rle", |
| 797 | BB->begin()); |
Owen Anderson | 4553791 | 2007-07-26 18:26:51 +0000 | [diff] [blame] | 798 | PN->reserveOperandSpace(std::distance(pred_begin(BB), pred_end(BB))); |
Owen Anderson | ab87027 | 2007-08-03 19:59:35 +0000 | [diff] [blame] | 799 | |
| 800 | if (Phis.count(BB) == 0) |
| 801 | Phis.insert(std::make_pair(BB, PN)); |
Owen Anderson | 4f9ba7c | 2007-07-30 16:57:08 +0000 | [diff] [blame] | 802 | |
Owen Anderson | 4553791 | 2007-07-26 18:26:51 +0000 | [diff] [blame] | 803 | // Fill in the incoming values for the block. |
Owen Anderson | 054ab94 | 2007-07-31 17:43:14 +0000 | [diff] [blame] | 804 | for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) { |
| 805 | Value* val = GetValueForBlock(*PI, orig, Phis); |
Owen Anderson | 054ab94 | 2007-07-31 17:43:14 +0000 | [diff] [blame] | 806 | PN->addIncoming(val, *PI); |
| 807 | } |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 808 | |
Nick Lewycky | 95f0ba2 | 2008-02-14 07:11:24 +0000 | [diff] [blame] | 809 | AliasAnalysis& AA = getAnalysis<AliasAnalysis>(); |
| 810 | AA.copyValue(orig, PN); |
Owen Anderson | 054ab94 | 2007-07-31 17:43:14 +0000 | [diff] [blame] | 811 | |
Owen Anderson | 62bc33c | 2007-08-16 22:02:55 +0000 | [diff] [blame] | 812 | // Attempt to collapse PHI nodes that are trivially redundant |
Owen Anderson | 1defe2d | 2007-08-16 22:51:56 +0000 | [diff] [blame] | 813 | Value* v = CollapsePhi(PN); |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 814 | if (!v) { |
| 815 | // Cache our phi construction results |
| 816 | phiMap[orig->getPointerOperand()].insert(PN); |
| 817 | return PN; |
Owen Anderson | 054ab94 | 2007-07-31 17:43:14 +0000 | [diff] [blame] | 818 | } |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 819 | |
| 820 | MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>(); |
Owen Anderson | 054ab94 | 2007-07-31 17:43:14 +0000 | [diff] [blame] | 821 | |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 822 | MD.removeInstruction(PN); |
| 823 | PN->replaceAllUsesWith(v); |
| 824 | |
| 825 | for (DenseMap<BasicBlock*, Value*>::iterator I = Phis.begin(), |
| 826 | E = Phis.end(); I != E; ++I) |
| 827 | if (I->second == PN) |
| 828 | I->second = v; |
| 829 | |
| 830 | PN->eraseFromParent(); |
| 831 | |
| 832 | Phis[BB] = v; |
| 833 | return v; |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 834 | } |
| 835 | |
Owen Anderson | 62bc33c | 2007-08-16 22:02:55 +0000 | [diff] [blame] | 836 | /// processNonLocalLoad - Attempt to eliminate a load whose dependencies are |
| 837 | /// non-local by performing PHI construction. |
Owen Anderson | 830db6a | 2007-08-02 18:16:06 +0000 | [diff] [blame] | 838 | bool GVN::processNonLocalLoad(LoadInst* L, |
Chris Lattner | 8e1e95c | 2008-03-21 22:01:16 +0000 | [diff] [blame] | 839 | SmallVectorImpl<Instruction*> &toErase) { |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 840 | MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>(); |
| 841 | |
Owen Anderson | 62bc33c | 2007-08-16 22:02:55 +0000 | [diff] [blame] | 842 | // Find the non-local dependencies of the load |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 843 | DenseMap<BasicBlock*, Value*> deps; |
Owen Anderson | 9066020 | 2007-08-01 22:01:54 +0000 | [diff] [blame] | 844 | MD.getNonLocalDependency(L, deps); |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 845 | |
| 846 | DenseMap<BasicBlock*, Value*> repl; |
Owen Anderson | a37226a | 2007-08-07 23:12:31 +0000 | [diff] [blame] | 847 | |
Owen Anderson | 62bc33c | 2007-08-16 22:02:55 +0000 | [diff] [blame] | 848 | // Filter out useless results (non-locals, etc) |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 849 | for (DenseMap<BasicBlock*, Value*>::iterator I = deps.begin(), E = deps.end(); |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 850 | I != E; ++I) { |
| 851 | if (I->second == MemoryDependenceAnalysis::None) |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 852 | return false; |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 853 | |
| 854 | if (I->second == MemoryDependenceAnalysis::NonLocal) |
Owen Anderson | 45c8388 | 2007-07-30 17:29:24 +0000 | [diff] [blame] | 855 | continue; |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 856 | |
| 857 | if (StoreInst* S = dyn_cast<StoreInst>(I->second)) { |
| 858 | if (S->getPointerOperand() != L->getPointerOperand()) |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 859 | return false; |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 860 | repl[I->first] = S->getOperand(0); |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 861 | } else if (LoadInst* LD = dyn_cast<LoadInst>(I->second)) { |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 862 | if (LD->getPointerOperand() != L->getPointerOperand()) |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 863 | return false; |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 864 | repl[I->first] = LD; |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 865 | } else { |
| 866 | return false; |
| 867 | } |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 868 | } |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 869 | |
Owen Anderson | 62bc33c | 2007-08-16 22:02:55 +0000 | [diff] [blame] | 870 | // Use cached PHI construction information from previous runs |
Owen Anderson | a37226a | 2007-08-07 23:12:31 +0000 | [diff] [blame] | 871 | SmallPtrSet<Instruction*, 4>& p = phiMap[L->getPointerOperand()]; |
| 872 | for (SmallPtrSet<Instruction*, 4>::iterator I = p.begin(), E = p.end(); |
| 873 | I != E; ++I) { |
| 874 | if ((*I)->getParent() == L->getParent()) { |
| 875 | MD.removeInstruction(L); |
| 876 | L->replaceAllUsesWith(*I); |
| 877 | toErase.push_back(L); |
| 878 | NumGVNLoad++; |
Owen Anderson | a37226a | 2007-08-07 23:12:31 +0000 | [diff] [blame] | 879 | return true; |
Owen Anderson | a37226a | 2007-08-07 23:12:31 +0000 | [diff] [blame] | 880 | } |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 881 | |
| 882 | repl.insert(std::make_pair((*I)->getParent(), *I)); |
Owen Anderson | a37226a | 2007-08-07 23:12:31 +0000 | [diff] [blame] | 883 | } |
| 884 | |
Owen Anderson | 62bc33c | 2007-08-16 22:02:55 +0000 | [diff] [blame] | 885 | // Perform PHI construction |
Owen Anderson | 0d16988 | 2007-07-25 22:03:06 +0000 | [diff] [blame] | 886 | SmallPtrSet<BasicBlock*, 4> visited; |
Owen Anderson | 1c2763d | 2007-08-02 17:56:05 +0000 | [diff] [blame] | 887 | Value* v = GetValueForBlock(L->getParent(), L, repl, true); |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 888 | |
| 889 | MD.removeInstruction(L); |
| 890 | L->replaceAllUsesWith(v); |
| 891 | toErase.push_back(L); |
Owen Anderson | a37226a | 2007-08-07 23:12:31 +0000 | [diff] [blame] | 892 | NumGVNLoad++; |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 893 | |
| 894 | return true; |
| 895 | } |
| 896 | |
Owen Anderson | 62bc33c | 2007-08-16 22:02:55 +0000 | [diff] [blame] | 897 | /// processLoad - Attempt to eliminate a load, first by eliminating it |
| 898 | /// locally, and then attempting non-local elimination if that fails. |
Chris Lattner | 8e1e95c | 2008-03-21 22:01:16 +0000 | [diff] [blame] | 899 | bool GVN::processLoad(LoadInst *L, DenseMap<Value*, LoadInst*> &lastLoad, |
| 900 | SmallVectorImpl<Instruction*> &toErase) { |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 901 | if (L->isVolatile()) { |
| 902 | lastLoad[L->getPointerOperand()] = L; |
| 903 | return false; |
| 904 | } |
| 905 | |
| 906 | Value* pointer = L->getPointerOperand(); |
| 907 | LoadInst*& last = lastLoad[pointer]; |
| 908 | |
| 909 | // ... to a pointer that has been loaded from before... |
| 910 | MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>(); |
Owen Anderson | 8e8278e | 2007-08-14 17:59:48 +0000 | [diff] [blame] | 911 | bool removedNonLocal = false; |
Owen Anderson | 9528f11 | 2007-08-09 04:42:44 +0000 | [diff] [blame] | 912 | Instruction* dep = MD.getDependency(L); |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 913 | if (dep == MemoryDependenceAnalysis::NonLocal && |
Owen Anderson | 8e8278e | 2007-08-14 17:59:48 +0000 | [diff] [blame] | 914 | L->getParent() != &L->getParent()->getParent()->getEntryBlock()) { |
| 915 | removedNonLocal = processNonLocalLoad(L, toErase); |
| 916 | |
| 917 | if (!removedNonLocal) |
| 918 | last = L; |
| 919 | |
| 920 | return removedNonLocal; |
| 921 | } |
| 922 | |
| 923 | |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 924 | bool deletedLoad = false; |
| 925 | |
Owen Anderson | 62bc33c | 2007-08-16 22:02:55 +0000 | [diff] [blame] | 926 | // Walk up the dependency chain until we either find |
| 927 | // a dependency we can use, or we can't walk any further |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 928 | while (dep != MemoryDependenceAnalysis::None && |
| 929 | dep != MemoryDependenceAnalysis::NonLocal && |
| 930 | (isa<LoadInst>(dep) || isa<StoreInst>(dep))) { |
| 931 | // ... that depends on a store ... |
| 932 | if (StoreInst* S = dyn_cast<StoreInst>(dep)) { |
| 933 | if (S->getPointerOperand() == pointer) { |
| 934 | // Remove it! |
| 935 | MD.removeInstruction(L); |
| 936 | |
| 937 | L->replaceAllUsesWith(S->getOperand(0)); |
| 938 | toErase.push_back(L); |
| 939 | deletedLoad = true; |
| 940 | NumGVNLoad++; |
| 941 | } |
| 942 | |
| 943 | // Whether we removed it or not, we can't |
| 944 | // go any further |
| 945 | break; |
| 946 | } else if (!last) { |
| 947 | // If we don't depend on a store, and we haven't |
| 948 | // been loaded before, bail. |
| 949 | break; |
| 950 | } else if (dep == last) { |
| 951 | // Remove it! |
| 952 | MD.removeInstruction(L); |
| 953 | |
| 954 | L->replaceAllUsesWith(last); |
| 955 | toErase.push_back(L); |
| 956 | deletedLoad = true; |
| 957 | NumGVNLoad++; |
| 958 | |
| 959 | break; |
| 960 | } else { |
Owen Anderson | 9528f11 | 2007-08-09 04:42:44 +0000 | [diff] [blame] | 961 | dep = MD.getDependency(L, dep); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 962 | } |
| 963 | } |
Eli Friedman | b6c36e4 | 2008-02-12 12:08:14 +0000 | [diff] [blame] | 964 | |
| 965 | if (dep != MemoryDependenceAnalysis::None && |
| 966 | dep != MemoryDependenceAnalysis::NonLocal && |
| 967 | isa<AllocationInst>(dep)) { |
| 968 | // Check that this load is actually from the |
| 969 | // allocation we found |
| 970 | Value* v = L->getOperand(0); |
| 971 | while (true) { |
| 972 | if (BitCastInst *BC = dyn_cast<BitCastInst>(v)) |
| 973 | v = BC->getOperand(0); |
| 974 | else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(v)) |
| 975 | v = GEP->getOperand(0); |
| 976 | else |
| 977 | break; |
| 978 | } |
| 979 | if (v == dep) { |
| 980 | // If this load depends directly on an allocation, there isn't |
| 981 | // anything stored there; therefore, we can optimize this load |
| 982 | // to undef. |
| 983 | MD.removeInstruction(L); |
| 984 | |
| 985 | L->replaceAllUsesWith(UndefValue::get(L->getType())); |
| 986 | toErase.push_back(L); |
| 987 | deletedLoad = true; |
| 988 | NumGVNLoad++; |
| 989 | } |
| 990 | } |
| 991 | |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 992 | if (!deletedLoad) |
| 993 | last = L; |
| 994 | |
| 995 | return deletedLoad; |
| 996 | } |
| 997 | |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 998 | /// isBytewiseValue - If the specified value can be set by repeating the same |
| 999 | /// byte in memory, return the i8 value that it is represented with. This is |
| 1000 | /// true for all i8 values obviously, but is also true for i32 0, i32 -1, |
| 1001 | /// i16 0xF0F0, double 0.0 etc. If the value can't be handled with a repeated |
| 1002 | /// byte store (e.g. i16 0x1234), return null. |
| 1003 | static Value *isBytewiseValue(Value *V) { |
| 1004 | // All byte-wide stores are splatable, even of arbitrary variables. |
| 1005 | if (V->getType() == Type::Int8Ty) return V; |
| 1006 | |
| 1007 | // Constant float and double values can be handled as integer values if the |
| 1008 | // corresponding integer value is "byteable". An important case is 0.0. |
| 1009 | if (ConstantFP *CFP = dyn_cast<ConstantFP>(V)) { |
| 1010 | if (CFP->getType() == Type::FloatTy) |
| 1011 | V = ConstantExpr::getBitCast(CFP, Type::Int32Ty); |
| 1012 | if (CFP->getType() == Type::DoubleTy) |
| 1013 | V = ConstantExpr::getBitCast(CFP, Type::Int64Ty); |
| 1014 | // Don't handle long double formats, which have strange constraints. |
| 1015 | } |
| 1016 | |
| 1017 | // We can handle constant integers that are power of two in size and a |
| 1018 | // multiple of 8 bits. |
| 1019 | if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) { |
| 1020 | unsigned Width = CI->getBitWidth(); |
| 1021 | if (isPowerOf2_32(Width) && Width > 8) { |
| 1022 | // We can handle this value if the recursive binary decomposition is the |
| 1023 | // same at all levels. |
| 1024 | APInt Val = CI->getValue(); |
| 1025 | APInt Val2; |
| 1026 | while (Val.getBitWidth() != 8) { |
| 1027 | unsigned NextWidth = Val.getBitWidth()/2; |
| 1028 | Val2 = Val.lshr(NextWidth); |
| 1029 | Val2.trunc(Val.getBitWidth()/2); |
| 1030 | Val.trunc(Val.getBitWidth()/2); |
| 1031 | |
| 1032 | // If the top/bottom halves aren't the same, reject it. |
| 1033 | if (Val != Val2) |
| 1034 | return 0; |
| 1035 | } |
| 1036 | return ConstantInt::get(Val); |
| 1037 | } |
| 1038 | } |
| 1039 | |
| 1040 | // Conceptually, we could handle things like: |
| 1041 | // %a = zext i8 %X to i16 |
| 1042 | // %b = shl i16 %a, 8 |
| 1043 | // %c = or i16 %a, %b |
| 1044 | // but until there is an example that actually needs this, it doesn't seem |
| 1045 | // worth worrying about. |
| 1046 | return 0; |
| 1047 | } |
| 1048 | |
Chris Lattner | b017c9e | 2008-03-22 05:37:16 +0000 | [diff] [blame] | 1049 | static int64_t GetOffsetFromIndex(const GetElementPtrInst *GEP, unsigned Idx, |
| 1050 | bool &VariableIdxFound, TargetData &TD) { |
| 1051 | // Skip over the first indices. |
| 1052 | gep_type_iterator GTI = gep_type_begin(GEP); |
| 1053 | for (unsigned i = 1; i != Idx; ++i, ++GTI) |
| 1054 | /*skip along*/; |
| 1055 | |
| 1056 | // Compute the offset implied by the rest of the indices. |
| 1057 | int64_t Offset = 0; |
| 1058 | for (unsigned i = Idx, e = GEP->getNumOperands(); i != e; ++i, ++GTI) { |
| 1059 | ConstantInt *OpC = dyn_cast<ConstantInt>(GEP->getOperand(i)); |
| 1060 | if (OpC == 0) |
| 1061 | return VariableIdxFound = true; |
| 1062 | if (OpC->isZero()) continue; // No offset. |
| 1063 | |
| 1064 | // Handle struct indices, which add their field offset to the pointer. |
| 1065 | if (const StructType *STy = dyn_cast<StructType>(*GTI)) { |
| 1066 | Offset += TD.getStructLayout(STy)->getElementOffset(OpC->getZExtValue()); |
| 1067 | continue; |
| 1068 | } |
| 1069 | |
| 1070 | // Otherwise, we have a sequential type like an array or vector. Multiply |
| 1071 | // the index by the ElementSize. |
| 1072 | uint64_t Size = TD.getABITypeSize(GTI.getIndexedType()); |
| 1073 | Offset += Size*OpC->getSExtValue(); |
| 1074 | } |
| 1075 | |
| 1076 | return Offset; |
| 1077 | } |
| 1078 | |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1079 | /// IsPointerOffset - Return true if Ptr1 is provably equal to Ptr2 plus a |
| 1080 | /// constant offset, and return that constant offset. For example, Ptr1 might |
| 1081 | /// be &A[42], and Ptr2 might be &A[40]. In this case offset would be -8. |
| 1082 | static bool IsPointerOffset(Value *Ptr1, Value *Ptr2, int64_t &Offset, |
| 1083 | TargetData &TD) { |
Chris Lattner | b017c9e | 2008-03-22 05:37:16 +0000 | [diff] [blame] | 1084 | // Right now we handle the case when Ptr1/Ptr2 are both GEPs with an identical |
| 1085 | // base. After that base, they may have some number of common (and |
| 1086 | // potentially variable) indices. After that they handle some constant |
| 1087 | // offset, which determines their offset from each other. At this point, we |
| 1088 | // handle no other case. |
| 1089 | GetElementPtrInst *GEP1 = dyn_cast<GetElementPtrInst>(Ptr1); |
| 1090 | GetElementPtrInst *GEP2 = dyn_cast<GetElementPtrInst>(Ptr2); |
| 1091 | if (!GEP1 || !GEP2 || GEP1->getOperand(0) != GEP2->getOperand(0)) |
| 1092 | return false; |
| 1093 | |
| 1094 | // Skip any common indices and track the GEP types. |
| 1095 | unsigned Idx = 1; |
| 1096 | for (; Idx != GEP1->getNumOperands() && Idx != GEP2->getNumOperands(); ++Idx) |
| 1097 | if (GEP1->getOperand(Idx) != GEP2->getOperand(Idx)) |
| 1098 | break; |
| 1099 | |
| 1100 | bool VariableIdxFound = false; |
| 1101 | int64_t Offset1 = GetOffsetFromIndex(GEP1, Idx, VariableIdxFound, TD); |
| 1102 | int64_t Offset2 = GetOffsetFromIndex(GEP2, Idx, VariableIdxFound, TD); |
| 1103 | if (VariableIdxFound) return false; |
| 1104 | |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1105 | Offset = Offset2-Offset1; |
| 1106 | return true; |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1107 | } |
| 1108 | |
| 1109 | |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1110 | /// MemsetRange - Represents a range of memset'd bytes with the ByteVal value. |
| 1111 | /// This allows us to analyze stores like: |
| 1112 | /// store 0 -> P+1 |
| 1113 | /// store 0 -> P+0 |
| 1114 | /// store 0 -> P+3 |
| 1115 | /// store 0 -> P+2 |
| 1116 | /// which sometimes happens with stores to arrays of structs etc. When we see |
| 1117 | /// the first store, we make a range [1, 2). The second store extends the range |
| 1118 | /// to [0, 2). The third makes a new range [2, 3). The fourth store joins the |
| 1119 | /// two ranges into [0, 3) which is memset'able. |
| 1120 | namespace { |
| 1121 | struct MemsetRange { |
| 1122 | // Start/End - A semi range that describes the span that this range covers. |
| 1123 | // The range is closed at the start and open at the end: [Start, End). |
| 1124 | int64_t Start, End; |
| 1125 | |
| 1126 | /// StartPtr - The getelementptr instruction that points to the start of the |
| 1127 | /// range. |
| 1128 | Value *StartPtr; |
| 1129 | |
| 1130 | /// Alignment - The known alignment of the first store. |
| 1131 | unsigned Alignment; |
| 1132 | |
| 1133 | /// TheStores - The actual stores that make up this range. |
| 1134 | SmallVector<StoreInst*, 16> TheStores; |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1135 | |
Chris Lattner | 9f8a6a7 | 2008-03-29 04:36:18 +0000 | [diff] [blame] | 1136 | bool isProfitableToUseMemset(const TargetData &TD) const; |
| 1137 | |
| 1138 | }; |
| 1139 | } // end anon namespace |
| 1140 | |
| 1141 | bool MemsetRange::isProfitableToUseMemset(const TargetData &TD) const { |
| 1142 | // If we found more than 8 stores to merge or 64 bytes, use memset. |
| 1143 | if (TheStores.size() >= 8 || End-Start >= 64) return true; |
| 1144 | |
| 1145 | // Assume that the code generator is capable of merging pairs of stores |
| 1146 | // together if it wants to. |
| 1147 | if (TheStores.size() <= 2) return false; |
| 1148 | |
| 1149 | // If we have fewer than 8 stores, it can still be worthwhile to do this. |
| 1150 | // For example, merging 4 i8 stores into an i32 store is useful almost always. |
| 1151 | // However, merging 2 32-bit stores isn't useful on a 32-bit architecture (the |
| 1152 | // memset will be split into 2 32-bit stores anyway) and doing so can |
| 1153 | // pessimize the llvm optimizer. |
| 1154 | // |
| 1155 | // Since we don't have perfect knowledge here, make some assumptions: assume |
| 1156 | // the maximum GPR width is the same size as the pointer size and assume that |
| 1157 | // this width can be stored. If so, check to see whether we will end up |
| 1158 | // actually reducing the number of stores used. |
| 1159 | unsigned Bytes = unsigned(End-Start); |
| 1160 | unsigned NumPointerStores = Bytes/TD.getPointerSize(); |
| 1161 | |
| 1162 | // Assume the remaining bytes if any are done a byte at a time. |
| 1163 | unsigned NumByteStores = Bytes - NumPointerStores*TD.getPointerSize(); |
| 1164 | |
| 1165 | // If we will reduce the # stores (according to this heuristic), do the |
| 1166 | // transformation. This encourages merging 4 x i8 -> i32 and 2 x i16 -> i32 |
| 1167 | // etc. |
| 1168 | return TheStores.size() > NumPointerStores+NumByteStores; |
| 1169 | } |
| 1170 | |
| 1171 | |
| 1172 | namespace { |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1173 | class MemsetRanges { |
| 1174 | /// Ranges - A sorted list of the memset ranges. We use std::list here |
| 1175 | /// because each element is relatively large and expensive to copy. |
| 1176 | std::list<MemsetRange> Ranges; |
| 1177 | typedef std::list<MemsetRange>::iterator range_iterator; |
| 1178 | TargetData &TD; |
| 1179 | public: |
| 1180 | MemsetRanges(TargetData &td) : TD(td) {} |
| 1181 | |
| 1182 | typedef std::list<MemsetRange>::const_iterator const_iterator; |
| 1183 | const_iterator begin() const { return Ranges.begin(); } |
| 1184 | const_iterator end() const { return Ranges.end(); } |
Chris Lattner | d22fe2b | 2008-03-29 04:52:12 +0000 | [diff] [blame] | 1185 | bool empty() const { return Ranges.empty(); } |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1186 | |
| 1187 | void addStore(int64_t OffsetFromFirst, StoreInst *SI); |
| 1188 | }; |
| 1189 | |
Chris Lattner | 9f8a6a7 | 2008-03-29 04:36:18 +0000 | [diff] [blame] | 1190 | } // end anon namespace |
| 1191 | |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1192 | |
| 1193 | /// addStore - Add a new store to the MemsetRanges data structure. This adds a |
| 1194 | /// new range for the specified store at the specified offset, merging into |
| 1195 | /// existing ranges as appropriate. |
| 1196 | void MemsetRanges::addStore(int64_t Start, StoreInst *SI) { |
| 1197 | int64_t End = Start+TD.getTypeStoreSize(SI->getOperand(0)->getType()); |
| 1198 | |
| 1199 | // Do a linear search of the ranges to see if this can be joined and/or to |
| 1200 | // find the insertion point in the list. We keep the ranges sorted for |
| 1201 | // simplicity here. This is a linear search of a linked list, which is ugly, |
| 1202 | // however the number of ranges is limited, so this won't get crazy slow. |
| 1203 | range_iterator I = Ranges.begin(), E = Ranges.end(); |
| 1204 | |
| 1205 | while (I != E && Start > I->End) |
| 1206 | ++I; |
| 1207 | |
| 1208 | // We now know that I == E, in which case we didn't find anything to merge |
| 1209 | // with, or that Start <= I->End. If End < I->Start or I == E, then we need |
| 1210 | // to insert a new range. Handle this now. |
| 1211 | if (I == E || End < I->Start) { |
| 1212 | MemsetRange &R = *Ranges.insert(I, MemsetRange()); |
| 1213 | R.Start = Start; |
| 1214 | R.End = End; |
| 1215 | R.StartPtr = SI->getPointerOperand(); |
| 1216 | R.Alignment = SI->getAlignment(); |
| 1217 | R.TheStores.push_back(SI); |
| 1218 | return; |
| 1219 | } |
| 1220 | |
| 1221 | // This store overlaps with I, add it. |
| 1222 | I->TheStores.push_back(SI); |
| 1223 | |
| 1224 | // At this point, we may have an interval that completely contains our store. |
| 1225 | // If so, just add it to the interval and return. |
| 1226 | if (I->Start <= Start && I->End >= End) |
| 1227 | return; |
| 1228 | |
| 1229 | // Now we know that Start <= I->End and End >= I->Start so the range overlaps |
| 1230 | // but is not entirely contained within the range. |
| 1231 | |
| 1232 | // See if the range extends the start of the range. In this case, it couldn't |
| 1233 | // possibly cause it to join the prior range, because otherwise we would have |
| 1234 | // stopped on *it*. |
Chris Lattner | 97ae12a | 2008-03-29 05:15:47 +0000 | [diff] [blame] | 1235 | if (Start < I->Start) { |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1236 | I->Start = Start; |
Chris Lattner | 97ae12a | 2008-03-29 05:15:47 +0000 | [diff] [blame] | 1237 | I->StartPtr = SI->getPointerOperand(); |
| 1238 | } |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1239 | |
| 1240 | // Now we know that Start <= I->End and Start >= I->Start (so the startpoint |
| 1241 | // is in or right at the end of I), and that End >= I->Start. Extend I out to |
| 1242 | // End. |
| 1243 | if (End > I->End) { |
| 1244 | I->End = End; |
| 1245 | range_iterator NextI = I;; |
| 1246 | while (++NextI != E && End >= NextI->Start) { |
| 1247 | // Merge the range in. |
| 1248 | I->TheStores.append(NextI->TheStores.begin(), NextI->TheStores.end()); |
| 1249 | if (NextI->End > I->End) |
| 1250 | I->End = NextI->End; |
| 1251 | Ranges.erase(NextI); |
| 1252 | NextI = I; |
| 1253 | } |
| 1254 | } |
| 1255 | } |
| 1256 | |
| 1257 | |
| 1258 | |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1259 | /// processStore - When GVN is scanning forward over instructions, we look for |
| 1260 | /// some other patterns to fold away. In particular, this looks for stores to |
| 1261 | /// neighboring locations of memory. If it sees enough consequtive ones |
| 1262 | /// (currently 4) it attempts to merge them together into a memcpy/memset. |
| 1263 | bool GVN::processStore(StoreInst *SI, SmallVectorImpl<Instruction*> &toErase) { |
Evan Cheng | 88ffddd | 2008-03-24 05:28:38 +0000 | [diff] [blame] | 1264 | if (!FormMemSet) return false; |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1265 | if (SI->isVolatile()) return false; |
| 1266 | |
| 1267 | // There are two cases that are interesting for this code to handle: memcpy |
| 1268 | // and memset. Right now we only handle memset. |
| 1269 | |
| 1270 | // Ensure that the value being stored is something that can be memset'able a |
| 1271 | // byte at a time like "0" or "-1" or any width, as well as things like |
| 1272 | // 0xA0A0A0A0 and 0.0. |
| 1273 | Value *ByteVal = isBytewiseValue(SI->getOperand(0)); |
| 1274 | if (!ByteVal) |
| 1275 | return false; |
| 1276 | |
| 1277 | TargetData &TD = getAnalysis<TargetData>(); |
| 1278 | AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); |
| 1279 | |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1280 | // Okay, so we now have a single store that can be splatable. Scan to find |
| 1281 | // all subsequent stores of the same value to offset from the same pointer. |
| 1282 | // Join these together into ranges, so we can decide whether contiguous blocks |
| 1283 | // are stored. |
| 1284 | MemsetRanges Ranges(TD); |
| 1285 | |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1286 | Value *StartPtr = SI->getPointerOperand(); |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1287 | |
Chris Lattner | b017c9e | 2008-03-22 05:37:16 +0000 | [diff] [blame] | 1288 | BasicBlock::iterator BI = SI; |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1289 | for (++BI; !isa<TerminatorInst>(BI); ++BI) { |
| 1290 | if (isa<CallInst>(BI) || isa<InvokeInst>(BI)) { |
| 1291 | // If the call is readnone, ignore it, otherwise bail out. We don't even |
| 1292 | // allow readonly here because we don't want something like: |
| 1293 | // A[1] = 2; strlen(A); A[2] = 2; -> memcpy(A, ...); strlen(A). |
| 1294 | if (AA.getModRefBehavior(CallSite::get(BI)) == |
| 1295 | AliasAnalysis::DoesNotAccessMemory) |
| 1296 | continue; |
Chris Lattner | d27290d | 2008-03-22 04:13:49 +0000 | [diff] [blame] | 1297 | |
| 1298 | // TODO: If this is a memset, try to join it in. |
| 1299 | |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1300 | break; |
| 1301 | } else if (isa<VAArgInst>(BI) || isa<LoadInst>(BI)) |
| 1302 | break; |
| 1303 | |
| 1304 | // If this is a non-store instruction it is fine, ignore it. |
| 1305 | StoreInst *NextStore = dyn_cast<StoreInst>(BI); |
| 1306 | if (NextStore == 0) continue; |
| 1307 | |
| 1308 | // If this is a store, see if we can merge it in. |
| 1309 | if (NextStore->isVolatile()) break; |
| 1310 | |
| 1311 | // Check to see if this stored value is of the same byte-splattable value. |
| 1312 | if (ByteVal != isBytewiseValue(NextStore->getOperand(0))) |
| 1313 | break; |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1314 | |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1315 | // Check to see if this store is to a constant offset from the start ptr. |
| 1316 | int64_t Offset; |
| 1317 | if (!IsPointerOffset(StartPtr, NextStore->getPointerOperand(), Offset, TD)) |
| 1318 | break; |
| 1319 | |
| 1320 | Ranges.addStore(Offset, NextStore); |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1321 | } |
Chris Lattner | d22fe2b | 2008-03-29 04:52:12 +0000 | [diff] [blame] | 1322 | |
| 1323 | // If we have no ranges, then we just had a single store with nothing that |
| 1324 | // could be merged in. This is a very common case of course. |
| 1325 | if (Ranges.empty()) |
| 1326 | return false; |
| 1327 | |
| 1328 | // If we had at least one store that could be merged in, add the starting |
| 1329 | // store as well. We try to avoid this unless there is at least something |
| 1330 | // interesting as a small compile-time optimization. |
| 1331 | Ranges.addStore(0, SI); |
| 1332 | |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1333 | |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1334 | Function *MemSetF = 0; |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1335 | |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1336 | // Now that we have full information about ranges, loop over the ranges and |
| 1337 | // emit memset's for anything big enough to be worthwhile. |
| 1338 | bool MadeChange = false; |
| 1339 | for (MemsetRanges::const_iterator I = Ranges.begin(), E = Ranges.end(); |
| 1340 | I != E; ++I) { |
| 1341 | const MemsetRange &Range = *I; |
| 1342 | |
Chris Lattner | 9f8a6a7 | 2008-03-29 04:36:18 +0000 | [diff] [blame] | 1343 | if (Range.TheStores.size() == 1) continue; |
| 1344 | |
| 1345 | // If it is profitable to lower this range to memset, do so now. |
| 1346 | if (!Range.isProfitableToUseMemset(TD)) |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1347 | continue; |
| 1348 | |
| 1349 | // Otherwise, we do want to transform this! Create a new memset. We put |
Chris Lattner | 97ae12a | 2008-03-29 05:15:47 +0000 | [diff] [blame] | 1350 | // the memset right before the first instruction that isn't part of this |
| 1351 | // memset block. This ensure that the memset is dominated by any addressing |
| 1352 | // instruction needed by the start of the block. |
| 1353 | BasicBlock::iterator InsertPt = BI; |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1354 | |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1355 | if (MemSetF == 0) |
| 1356 | MemSetF = Intrinsic::getDeclaration(SI->getParent()->getParent() |
Chris Lattner | d27290d | 2008-03-22 04:13:49 +0000 | [diff] [blame] | 1357 | ->getParent(), Intrinsic::memset_i64); |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1358 | |
Chris Lattner | 97ae12a | 2008-03-29 05:15:47 +0000 | [diff] [blame] | 1359 | // Get the starting pointer of the block. |
| 1360 | StartPtr = Range.StartPtr; |
Chris Lattner | d27290d | 2008-03-22 04:13:49 +0000 | [diff] [blame] | 1361 | |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1362 | // Cast the start ptr to be i8* as memset requires. |
| 1363 | const Type *i8Ptr = PointerType::getUnqual(Type::Int8Ty); |
| 1364 | if (StartPtr->getType() != i8Ptr) |
| 1365 | StartPtr = new BitCastInst(StartPtr, i8Ptr, StartPtr->getNameStart(), |
| 1366 | InsertPt); |
Chris Lattner | d27290d | 2008-03-22 04:13:49 +0000 | [diff] [blame] | 1367 | |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1368 | Value *Ops[] = { |
| 1369 | StartPtr, ByteVal, // Start, value |
| 1370 | ConstantInt::get(Type::Int64Ty, Range.End-Range.Start), // size |
| 1371 | ConstantInt::get(Type::Int32Ty, Range.Alignment) // align |
| 1372 | }; |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 1373 | Value *C = CallInst::Create(MemSetF, Ops, Ops+4, "", InsertPt); |
Chris Lattner | 9f8a6a7 | 2008-03-29 04:36:18 +0000 | [diff] [blame] | 1374 | DEBUG(cerr << "Replace stores:\n"; |
| 1375 | for (unsigned i = 0, e = Range.TheStores.size(); i != e; ++i) |
| 1376 | cerr << *Range.TheStores[i]; |
| 1377 | cerr << "With: " << *C); C=C; |
Chris Lattner | d27290d | 2008-03-22 04:13:49 +0000 | [diff] [blame] | 1378 | |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1379 | // Zap all the stores. |
| 1380 | toErase.append(Range.TheStores.begin(), Range.TheStores.end()); |
| 1381 | ++NumMemSetInfer; |
| 1382 | MadeChange = true; |
| 1383 | } |
Chris Lattner | d27290d | 2008-03-22 04:13:49 +0000 | [diff] [blame] | 1384 | |
Chris Lattner | 7f0965e | 2008-03-28 06:45:13 +0000 | [diff] [blame] | 1385 | return MadeChange; |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1386 | } |
| 1387 | |
| 1388 | |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1389 | /// performCallSlotOptzn - takes a memcpy and a call that it depends on, |
| 1390 | /// and checks for the possibility of a call slot optimization by having |
| 1391 | /// the call write its result directly into the destination of the memcpy. |
Chris Lattner | 8e1e95c | 2008-03-21 22:01:16 +0000 | [diff] [blame] | 1392 | bool GVN::performCallSlotOptzn(MemCpyInst *cpy, CallInst *C, |
| 1393 | SmallVectorImpl<Instruction*> &toErase) { |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1394 | // The general transformation to keep in mind is |
| 1395 | // |
| 1396 | // call @func(..., src, ...) |
| 1397 | // memcpy(dest, src, ...) |
| 1398 | // |
| 1399 | // -> |
| 1400 | // |
| 1401 | // memcpy(dest, src, ...) |
| 1402 | // call @func(..., dest, ...) |
| 1403 | // |
| 1404 | // Since moving the memcpy is technically awkward, we additionally check that |
| 1405 | // src only holds uninitialized values at the moment of the call, meaning that |
| 1406 | // the memcpy can be discarded rather than moved. |
Owen Anderson | fa113f8 | 2008-02-19 03:27:34 +0000 | [diff] [blame] | 1407 | |
Owen Anderson | 967552e | 2008-02-19 07:07:51 +0000 | [diff] [blame] | 1408 | // Deliberately get the source and destination with bitcasts stripped away, |
| 1409 | // because we'll need to do type comparisons based on the underlying type. |
Owen Anderson | 5aa4f2a | 2008-02-18 09:24:53 +0000 | [diff] [blame] | 1410 | Value* cpyDest = cpy->getDest(); |
Owen Anderson | 61c24e9 | 2008-02-19 06:35:43 +0000 | [diff] [blame] | 1411 | Value* cpySrc = cpy->getSource(); |
| 1412 | CallSite CS = CallSite::get(C); |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1413 | |
| 1414 | // We need to be able to reason about the size of the memcpy, so we require |
| 1415 | // that it be a constant. |
| 1416 | ConstantInt* cpyLength = dyn_cast<ConstantInt>(cpy->getLength()); |
| 1417 | if (!cpyLength) |
Owen Anderson | 5aa4f2a | 2008-02-18 09:24:53 +0000 | [diff] [blame] | 1418 | return false; |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1419 | |
| 1420 | // Require that src be an alloca. This simplifies the reasoning considerably. |
| 1421 | AllocaInst* srcAlloca = dyn_cast<AllocaInst>(cpySrc); |
| 1422 | if (!srcAlloca) |
| 1423 | return false; |
| 1424 | |
| 1425 | // Check that all of src is copied to dest. |
| 1426 | TargetData& TD = getAnalysis<TargetData>(); |
| 1427 | |
| 1428 | ConstantInt* srcArraySize = dyn_cast<ConstantInt>(srcAlloca->getArraySize()); |
| 1429 | if (!srcArraySize) |
| 1430 | return false; |
| 1431 | |
| 1432 | uint64_t srcSize = TD.getABITypeSize(srcAlloca->getAllocatedType()) * |
| 1433 | srcArraySize->getZExtValue(); |
| 1434 | |
| 1435 | if (cpyLength->getZExtValue() < srcSize) |
| 1436 | return false; |
| 1437 | |
| 1438 | // Check that accessing the first srcSize bytes of dest will not cause a |
| 1439 | // trap. Otherwise the transform is invalid since it might cause a trap |
| 1440 | // to occur earlier than it otherwise would. |
| 1441 | if (AllocaInst* A = dyn_cast<AllocaInst>(cpyDest)) { |
| 1442 | // The destination is an alloca. Check it is larger than srcSize. |
| 1443 | ConstantInt* destArraySize = dyn_cast<ConstantInt>(A->getArraySize()); |
| 1444 | if (!destArraySize) |
| 1445 | return false; |
| 1446 | |
| 1447 | uint64_t destSize = TD.getABITypeSize(A->getAllocatedType()) * |
| 1448 | destArraySize->getZExtValue(); |
| 1449 | |
| 1450 | if (destSize < srcSize) |
| 1451 | return false; |
| 1452 | } else if (Argument* A = dyn_cast<Argument>(cpyDest)) { |
| 1453 | // If the destination is an sret parameter then only accesses that are |
| 1454 | // outside of the returned struct type can trap. |
| 1455 | if (!A->hasStructRetAttr()) |
| 1456 | return false; |
| 1457 | |
| 1458 | const Type* StructTy = cast<PointerType>(A->getType())->getElementType(); |
| 1459 | uint64_t destSize = TD.getABITypeSize(StructTy); |
| 1460 | |
| 1461 | if (destSize < srcSize) |
| 1462 | return false; |
| 1463 | } else { |
| 1464 | return false; |
| 1465 | } |
| 1466 | |
| 1467 | // Check that src is not accessed except via the call and the memcpy. This |
| 1468 | // guarantees that it holds only undefined values when passed in (so the final |
| 1469 | // memcpy can be dropped), that it is not read or written between the call and |
| 1470 | // the memcpy, and that writing beyond the end of it is undefined. |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1471 | SmallVector<User*, 8> srcUseList(srcAlloca->use_begin(), |
| 1472 | srcAlloca->use_end()); |
| 1473 | while (!srcUseList.empty()) { |
| 1474 | User* UI = srcUseList.back(); |
| 1475 | srcUseList.pop_back(); |
| 1476 | |
| 1477 | if (isa<GetElementPtrInst>(UI) || isa<BitCastInst>(UI)) { |
| 1478 | for (User::use_iterator I = UI->use_begin(), E = UI->use_end(); |
| 1479 | I != E; ++I) |
| 1480 | srcUseList.push_back(*I); |
| 1481 | } else if (UI != C && UI != cpy) { |
| 1482 | return false; |
| 1483 | } |
| 1484 | } |
| 1485 | |
Owen Anderson | 0f7ea1a | 2008-02-25 00:40:41 +0000 | [diff] [blame] | 1486 | // Since we're changing the parameter to the callsite, we need to make sure |
| 1487 | // that what would be the new parameter dominates the callsite. |
| 1488 | DominatorTree& DT = getAnalysis<DominatorTree>(); |
| 1489 | if (Instruction* cpyDestInst = dyn_cast<Instruction>(cpyDest)) |
| 1490 | if (!DT.dominates(cpyDestInst, C)) |
| 1491 | return false; |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1492 | |
| 1493 | // In addition to knowing that the call does not access src in some |
| 1494 | // unexpected manner, for example via a global, which we deduce from |
| 1495 | // the use analysis, we also need to know that it does not sneakily |
| 1496 | // access dest. We rely on AA to figure this out for us. |
Owen Anderson | 61c24e9 | 2008-02-19 06:35:43 +0000 | [diff] [blame] | 1497 | AliasAnalysis& AA = getAnalysis<AliasAnalysis>(); |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1498 | if (AA.getModRefInfo(C, cpy->getRawDest(), srcSize) != |
Owen Anderson | 61c24e9 | 2008-02-19 06:35:43 +0000 | [diff] [blame] | 1499 | AliasAnalysis::NoModRef) |
| 1500 | return false; |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1501 | |
| 1502 | // All the checks have passed, so do the transformation. |
| 1503 | for (unsigned i = 0; i < CS.arg_size(); ++i) |
Owen Anderson | 8a97fdd | 2008-03-13 22:07:10 +0000 | [diff] [blame] | 1504 | if (CS.getArgument(i) == cpySrc) { |
| 1505 | if (cpySrc->getType() != cpyDest->getType()) |
| 1506 | cpyDest = CastInst::createPointerCast(cpyDest, cpySrc->getType(), |
| 1507 | cpyDest->getName(), C); |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1508 | CS.setArgument(i, cpyDest); |
Owen Anderson | 8a97fdd | 2008-03-13 22:07:10 +0000 | [diff] [blame] | 1509 | } |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1510 | |
Owen Anderson | 61c24e9 | 2008-02-19 06:35:43 +0000 | [diff] [blame] | 1511 | // Drop any cached information about the call, because we may have changed |
| 1512 | // its dependence information by changing its parameter. |
Owen Anderson | 5aa4f2a | 2008-02-18 09:24:53 +0000 | [diff] [blame] | 1513 | MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>(); |
| 1514 | MD.dropInstruction(C); |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1515 | |
Owen Anderson | 5aa4f2a | 2008-02-18 09:24:53 +0000 | [diff] [blame] | 1516 | // Remove the memcpy |
Owen Anderson | 61d30a8 | 2008-02-20 08:23:02 +0000 | [diff] [blame] | 1517 | MD.removeInstruction(cpy); |
Owen Anderson | 5aa4f2a | 2008-02-18 09:24:53 +0000 | [diff] [blame] | 1518 | toErase.push_back(cpy); |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1519 | |
Owen Anderson | 5aa4f2a | 2008-02-18 09:24:53 +0000 | [diff] [blame] | 1520 | return true; |
| 1521 | } |
| 1522 | |
Owen Anderson | 30b4bd4 | 2008-02-12 21:15:18 +0000 | [diff] [blame] | 1523 | /// processMemCpy - perform simplication of memcpy's. If we have memcpy A which |
| 1524 | /// copies X to Y, and memcpy B which copies Y to Z, then we can rewrite B to be |
| 1525 | /// a memcpy from X to Z (or potentially a memmove, depending on circumstances). |
| 1526 | /// This allows later passes to remove the first memcpy altogether. |
Owen Anderson | 7acc0af | 2008-02-19 03:09:45 +0000 | [diff] [blame] | 1527 | bool GVN::processMemCpy(MemCpyInst* M, MemCpyInst* MDep, |
Chris Lattner | 8e1e95c | 2008-03-21 22:01:16 +0000 | [diff] [blame] | 1528 | SmallVectorImpl<Instruction*> &toErase) { |
Owen Anderson | 30b4bd4 | 2008-02-12 21:15:18 +0000 | [diff] [blame] | 1529 | // We can only transforms memcpy's where the dest of one is the source of the |
| 1530 | // other |
Owen Anderson | 30b4bd4 | 2008-02-12 21:15:18 +0000 | [diff] [blame] | 1531 | if (M->getSource() != MDep->getDest()) |
| 1532 | return false; |
| 1533 | |
| 1534 | // Second, the length of the memcpy's must be the same, or the preceeding one |
| 1535 | // must be larger than the following one. |
| 1536 | ConstantInt* C1 = dyn_cast<ConstantInt>(MDep->getLength()); |
| 1537 | ConstantInt* C2 = dyn_cast<ConstantInt>(M->getLength()); |
| 1538 | if (!C1 || !C2) |
| 1539 | return false; |
| 1540 | |
Owen Anderson | 77db50f | 2008-02-26 23:06:17 +0000 | [diff] [blame] | 1541 | uint64_t DepSize = C1->getValue().getZExtValue(); |
| 1542 | uint64_t CpySize = C2->getValue().getZExtValue(); |
Owen Anderson | 30b4bd4 | 2008-02-12 21:15:18 +0000 | [diff] [blame] | 1543 | |
| 1544 | if (DepSize < CpySize) |
| 1545 | return false; |
| 1546 | |
| 1547 | // Finally, we have to make sure that the dest of the second does not |
| 1548 | // alias the source of the first |
| 1549 | AliasAnalysis& AA = getAnalysis<AliasAnalysis>(); |
| 1550 | if (AA.alias(M->getRawDest(), CpySize, MDep->getRawSource(), DepSize) != |
| 1551 | AliasAnalysis::NoAlias) |
| 1552 | return false; |
| 1553 | else if (AA.alias(M->getRawDest(), CpySize, M->getRawSource(), CpySize) != |
| 1554 | AliasAnalysis::NoAlias) |
| 1555 | return false; |
| 1556 | else if (AA.alias(MDep->getRawDest(), DepSize, MDep->getRawSource(), DepSize) |
| 1557 | != AliasAnalysis::NoAlias) |
| 1558 | return false; |
| 1559 | |
| 1560 | // If all checks passed, then we can transform these memcpy's |
Owen Anderson | 7acc0af | 2008-02-19 03:09:45 +0000 | [diff] [blame] | 1561 | Function* MemCpyFun = Intrinsic::getDeclaration( |
Owen Anderson | 30b4bd4 | 2008-02-12 21:15:18 +0000 | [diff] [blame] | 1562 | M->getParent()->getParent()->getParent(), |
Owen Anderson | 7acc0af | 2008-02-19 03:09:45 +0000 | [diff] [blame] | 1563 | M->getIntrinsicID()); |
Owen Anderson | 30b4bd4 | 2008-02-12 21:15:18 +0000 | [diff] [blame] | 1564 | |
| 1565 | std::vector<Value*> args; |
| 1566 | args.push_back(M->getRawDest()); |
| 1567 | args.push_back(MDep->getRawSource()); |
| 1568 | args.push_back(M->getLength()); |
| 1569 | args.push_back(M->getAlignment()); |
| 1570 | |
Gabor Greif | 051a950 | 2008-04-06 20:25:17 +0000 | [diff] [blame^] | 1571 | CallInst* C = CallInst::Create(MemCpyFun, args.begin(), args.end(), "", M); |
Owen Anderson | 30b4bd4 | 2008-02-12 21:15:18 +0000 | [diff] [blame] | 1572 | |
Owen Anderson | 7acc0af | 2008-02-19 03:09:45 +0000 | [diff] [blame] | 1573 | MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>(); |
Owen Anderson | 30b4bd4 | 2008-02-12 21:15:18 +0000 | [diff] [blame] | 1574 | if (MD.getDependency(C) == MDep) { |
| 1575 | MD.dropInstruction(M); |
| 1576 | toErase.push_back(M); |
| 1577 | return true; |
Owen Anderson | 30b4bd4 | 2008-02-12 21:15:18 +0000 | [diff] [blame] | 1578 | } |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 1579 | |
| 1580 | MD.removeInstruction(C); |
| 1581 | toErase.push_back(C); |
| 1582 | return false; |
Owen Anderson | 30b4bd4 | 2008-02-12 21:15:18 +0000 | [diff] [blame] | 1583 | } |
| 1584 | |
Owen Anderson | 36057c7 | 2007-08-14 18:16:29 +0000 | [diff] [blame] | 1585 | /// processInstruction - When calculating availability, handle an instruction |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 1586 | /// by inserting it into the appropriate sets |
Chris Lattner | 8e1e95c | 2008-03-21 22:01:16 +0000 | [diff] [blame] | 1587 | bool GVN::processInstruction(Instruction *I, ValueNumberedSet &currAvail, |
| 1588 | DenseMap<Value*, LoadInst*> &lastSeenLoad, |
| 1589 | SmallVectorImpl<Instruction*> &toErase) { |
| 1590 | if (LoadInst* L = dyn_cast<LoadInst>(I)) |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 1591 | return processLoad(L, lastSeenLoad, toErase); |
Chris Lattner | 8e1e95c | 2008-03-21 22:01:16 +0000 | [diff] [blame] | 1592 | |
Chris Lattner | 641dae1 | 2008-03-22 00:31:52 +0000 | [diff] [blame] | 1593 | if (StoreInst *SI = dyn_cast<StoreInst>(I)) |
| 1594 | return processStore(SI, toErase); |
| 1595 | |
Chris Lattner | 8e1e95c | 2008-03-21 22:01:16 +0000 | [diff] [blame] | 1596 | if (MemCpyInst* M = dyn_cast<MemCpyInst>(I)) { |
Owen Anderson | 7acc0af | 2008-02-19 03:09:45 +0000 | [diff] [blame] | 1597 | MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>(); |
| 1598 | |
| 1599 | // The are two possible optimizations we can do for memcpy: |
| 1600 | // a) memcpy-memcpy xform which exposes redundance for DSE |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1601 | // b) call-memcpy xform for return slot optimization |
Owen Anderson | 7acc0af | 2008-02-19 03:09:45 +0000 | [diff] [blame] | 1602 | Instruction* dep = MD.getDependency(M); |
| 1603 | if (dep == MemoryDependenceAnalysis::None || |
| 1604 | dep == MemoryDependenceAnalysis::NonLocal) |
| 1605 | return false; |
Chris Lattner | e42ce73 | 2008-02-19 06:53:20 +0000 | [diff] [blame] | 1606 | if (MemCpyInst *MemCpy = dyn_cast<MemCpyInst>(dep)) |
| 1607 | return processMemCpy(M, MemCpy, toErase); |
Chris Lattner | 0a76a62 | 2008-02-19 06:52:38 +0000 | [diff] [blame] | 1608 | if (CallInst* C = dyn_cast<CallInst>(dep)) |
Owen Anderson | 6bb0bd5 | 2008-03-12 07:37:44 +0000 | [diff] [blame] | 1609 | return performCallSlotOptzn(M, C, toErase); |
Chris Lattner | 0a76a62 | 2008-02-19 06:52:38 +0000 | [diff] [blame] | 1610 | return false; |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 1611 | } |
| 1612 | |
| 1613 | unsigned num = VN.lookup_or_add(I); |
| 1614 | |
Owen Anderson | 62bc33c | 2007-08-16 22:02:55 +0000 | [diff] [blame] | 1615 | // Collapse PHI nodes |
Owen Anderson | 31f4967 | 2007-08-14 18:33:27 +0000 | [diff] [blame] | 1616 | if (PHINode* p = dyn_cast<PHINode>(I)) { |
Owen Anderson | 1defe2d | 2007-08-16 22:51:56 +0000 | [diff] [blame] | 1617 | Value* constVal = CollapsePhi(p); |
Owen Anderson | 31f4967 | 2007-08-14 18:33:27 +0000 | [diff] [blame] | 1618 | |
| 1619 | if (constVal) { |
Owen Anderson | 1defe2d | 2007-08-16 22:51:56 +0000 | [diff] [blame] | 1620 | for (PhiMapType::iterator PI = phiMap.begin(), PE = phiMap.end(); |
| 1621 | PI != PE; ++PI) |
| 1622 | if (PI->second.count(p)) |
| 1623 | PI->second.erase(p); |
Owen Anderson | 31f4967 | 2007-08-14 18:33:27 +0000 | [diff] [blame] | 1624 | |
Owen Anderson | 1defe2d | 2007-08-16 22:51:56 +0000 | [diff] [blame] | 1625 | p->replaceAllUsesWith(constVal); |
| 1626 | toErase.push_back(p); |
Owen Anderson | 31f4967 | 2007-08-14 18:33:27 +0000 | [diff] [blame] | 1627 | } |
Owen Anderson | 62bc33c | 2007-08-16 22:02:55 +0000 | [diff] [blame] | 1628 | // Perform value-number based elimination |
Owen Anderson | 31f4967 | 2007-08-14 18:33:27 +0000 | [diff] [blame] | 1629 | } else if (currAvail.test(num)) { |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 1630 | Value* repl = find_leader(currAvail, num); |
| 1631 | |
Owen Anderson | 00a6d14 | 2007-11-26 02:26:36 +0000 | [diff] [blame] | 1632 | if (CallInst* CI = dyn_cast<CallInst>(I)) { |
| 1633 | AliasAnalysis& AA = getAnalysis<AliasAnalysis>(); |
Duncan Sands | dff6710 | 2007-12-01 07:51:45 +0000 | [diff] [blame] | 1634 | if (!AA.doesNotAccessMemory(CI)) { |
Owen Anderson | 00a6d14 | 2007-11-26 02:26:36 +0000 | [diff] [blame] | 1635 | MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>(); |
Owen Anderson | 1fb1364 | 2007-11-29 18:02:22 +0000 | [diff] [blame] | 1636 | if (cast<Instruction>(repl)->getParent() != CI->getParent() || |
| 1637 | MD.getDependency(CI) != MD.getDependency(cast<CallInst>(repl))) { |
Owen Anderson | 00a6d14 | 2007-11-26 02:26:36 +0000 | [diff] [blame] | 1638 | // There must be an intervening may-alias store, so nothing from |
| 1639 | // this point on will be able to be replaced with the preceding call |
| 1640 | currAvail.erase(repl); |
| 1641 | currAvail.insert(I); |
| 1642 | |
| 1643 | return false; |
| 1644 | } |
| 1645 | } |
| 1646 | } |
| 1647 | |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 1648 | // Remove it! |
| 1649 | MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>(); |
| 1650 | MD.removeInstruction(I); |
| 1651 | |
Owen Anderson | bf7d0bc | 2007-07-31 23:27:13 +0000 | [diff] [blame] | 1652 | VN.erase(I); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 1653 | I->replaceAllUsesWith(repl); |
| 1654 | toErase.push_back(I); |
| 1655 | return true; |
| 1656 | } else if (!I->isTerminator()) { |
| 1657 | currAvail.set(num); |
| 1658 | currAvail.insert(I); |
| 1659 | } |
| 1660 | |
| 1661 | return false; |
| 1662 | } |
| 1663 | |
| 1664 | // GVN::runOnFunction - This is the main transformation entry point for a |
| 1665 | // function. |
| 1666 | // |
Owen Anderson | 3e75a42 | 2007-08-14 18:04:11 +0000 | [diff] [blame] | 1667 | bool GVN::runOnFunction(Function& F) { |
Owen Anderson | b388ca9 | 2007-10-18 19:39:33 +0000 | [diff] [blame] | 1668 | VN.setAliasAnalysis(&getAnalysis<AliasAnalysis>()); |
| 1669 | |
Owen Anderson | 3e75a42 | 2007-08-14 18:04:11 +0000 | [diff] [blame] | 1670 | bool changed = false; |
| 1671 | bool shouldContinue = true; |
| 1672 | |
| 1673 | while (shouldContinue) { |
| 1674 | shouldContinue = iterateOnFunction(F); |
| 1675 | changed |= shouldContinue; |
| 1676 | } |
| 1677 | |
| 1678 | return changed; |
| 1679 | } |
| 1680 | |
| 1681 | |
| 1682 | // GVN::iterateOnFunction - Executes one iteration of GVN |
| 1683 | bool GVN::iterateOnFunction(Function &F) { |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 1684 | // Clean out global sets from any previous functions |
| 1685 | VN.clear(); |
| 1686 | availableOut.clear(); |
Owen Anderson | a37226a | 2007-08-07 23:12:31 +0000 | [diff] [blame] | 1687 | phiMap.clear(); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 1688 | |
| 1689 | bool changed_function = false; |
| 1690 | |
| 1691 | DominatorTree &DT = getAnalysis<DominatorTree>(); |
| 1692 | |
Chris Lattner | 97ae12a | 2008-03-29 05:15:47 +0000 | [diff] [blame] | 1693 | SmallVector<Instruction*, 8> toErase; |
Chris Lattner | 2e60701 | 2008-03-21 21:33:23 +0000 | [diff] [blame] | 1694 | DenseMap<Value*, LoadInst*> lastSeenLoad; |
| 1695 | |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 1696 | // Top-down walk of the dominator tree |
| 1697 | for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()), |
| 1698 | E = df_end(DT.getRootNode()); DI != E; ++DI) { |
| 1699 | |
| 1700 | // Get the set to update for this block |
| 1701 | ValueNumberedSet& currAvail = availableOut[DI->getBlock()]; |
Chris Lattner | 2e60701 | 2008-03-21 21:33:23 +0000 | [diff] [blame] | 1702 | lastSeenLoad.clear(); |
| 1703 | |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 1704 | BasicBlock* BB = DI->getBlock(); |
| 1705 | |
| 1706 | // A block inherits AVAIL_OUT from its dominator |
| 1707 | if (DI->getIDom() != 0) |
| 1708 | currAvail = availableOut[DI->getIDom()->getBlock()]; |
| 1709 | |
| 1710 | for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); |
Chris Lattner | 97ae12a | 2008-03-29 05:15:47 +0000 | [diff] [blame] | 1711 | BI != BE;) { |
Owen Anderson | 830db6a | 2007-08-02 18:16:06 +0000 | [diff] [blame] | 1712 | changed_function |= processInstruction(BI, currAvail, |
| 1713 | lastSeenLoad, toErase); |
Chris Lattner | 97ae12a | 2008-03-29 05:15:47 +0000 | [diff] [blame] | 1714 | if (toErase.empty()) { |
| 1715 | ++BI; |
| 1716 | continue; |
| 1717 | } |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 1718 | |
Chris Lattner | 97ae12a | 2008-03-29 05:15:47 +0000 | [diff] [blame] | 1719 | // If we need some instructions deleted, do it now. |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 1720 | NumGVNInstr += toErase.size(); |
| 1721 | |
Chris Lattner | 97ae12a | 2008-03-29 05:15:47 +0000 | [diff] [blame] | 1722 | // Avoid iterator invalidation. |
| 1723 | bool AtStart = BI == BB->begin(); |
| 1724 | if (!AtStart) |
| 1725 | --BI; |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 1726 | |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 1727 | for (SmallVector<Instruction*, 4>::iterator I = toErase.begin(), |
Chris Lattner | 88365bb | 2008-03-21 21:14:38 +0000 | [diff] [blame] | 1728 | E = toErase.end(); I != E; ++I) |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 1729 | (*I)->eraseFromParent(); |
Owen Anderson | 5fc4aba | 2007-12-08 01:37:09 +0000 | [diff] [blame] | 1730 | |
Chris Lattner | 97ae12a | 2008-03-29 05:15:47 +0000 | [diff] [blame] | 1731 | if (AtStart) |
| 1732 | BI = BB->begin(); |
| 1733 | else |
| 1734 | ++BI; |
| 1735 | |
Owen Anderson | 0cd3203 | 2007-07-25 19:57:03 +0000 | [diff] [blame] | 1736 | toErase.clear(); |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 1737 | } |
| 1738 | } |
| 1739 | |
Owen Anderson | 1ad2cb7 | 2007-07-24 17:55:58 +0000 | [diff] [blame] | 1740 | return changed_function; |
| 1741 | } |