1 //===- llvm/Analysis/TargetTransformInfo.cpp ------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #define DEBUG_TYPE "tti" 11 #include "llvm/Analysis/TargetTransformInfo.h" 12 #include "llvm/IR/DataLayout.h" 13 #include "llvm/IR/Operator.h" 14 #include "llvm/IR/Instruction.h" 15 #include "llvm/IR/IntrinsicInst.h" 16 #include "llvm/IR/Instructions.h" 17 #include "llvm/Support/CallSite.h" 18 #include "llvm/Support/ErrorHandling.h" 19 20 using namespace llvm; 21 22 // Setup the analysis group to manage the TargetTransformInfo passes. 23 INITIALIZE_ANALYSIS_GROUP(TargetTransformInfo, "Target Information", NoTTI) 24 char TargetTransformInfo::ID = 0; 25 26 TargetTransformInfo::~TargetTransformInfo() { 27 } 28 29 void TargetTransformInfo::pushTTIStack(Pass *P) { 30 TopTTI = this; 31 PrevTTI = &P->getAnalysis<TargetTransformInfo>(); 32 33 // Walk up the chain and update the top TTI pointer. 34 for (TargetTransformInfo *PTTI = PrevTTI; PTTI; PTTI = PTTI->PrevTTI) 35 PTTI->TopTTI = this; 36 } 37 38 void TargetTransformInfo::popTTIStack() { 39 TopTTI = 0; 40 41 // Walk up the chain and update the top TTI pointer. 42 for (TargetTransformInfo *PTTI = PrevTTI; PTTI; PTTI = PTTI->PrevTTI) 43 PTTI->TopTTI = PrevTTI; 44 45 PrevTTI = 0; 46 } 47 48 void TargetTransformInfo::getAnalysisUsage(AnalysisUsage &AU) const { 49 AU.addRequired<TargetTransformInfo>(); 50 } 51 52 unsigned TargetTransformInfo::getOperationCost(unsigned Opcode, Type *Ty, 53 Type *OpTy) const { 54 return PrevTTI->getOperationCost(Opcode, Ty, OpTy); 55 } 56 57 unsigned TargetTransformInfo::getGEPCost( 58 const Value *Ptr, ArrayRef<const Value *> Operands) const { 59 return PrevTTI->getGEPCost(Ptr, Operands); 60 } 61 62 unsigned TargetTransformInfo::getCallCost(FunctionType *FTy, 63 int NumArgs) const { 64 return PrevTTI->getCallCost(FTy, NumArgs); 65 } 66 67 unsigned TargetTransformInfo::getCallCost(const Function *F, 68 int NumArgs) const { 69 return PrevTTI->getCallCost(F, NumArgs); 70 } 71 72 unsigned TargetTransformInfo::getCallCost( 73 const Function *F, ArrayRef<const Value *> Arguments) const { 74 return PrevTTI->getCallCost(F, Arguments); 75 } 76 77 unsigned TargetTransformInfo::getIntrinsicCost( 78 Intrinsic::ID IID, Type *RetTy, ArrayRef<Type *> ParamTys) const { 79 return PrevTTI->getIntrinsicCost(IID, RetTy, ParamTys); 80 } 81 82 unsigned TargetTransformInfo::getIntrinsicCost( 83 Intrinsic::ID IID, Type *RetTy, ArrayRef<const Value *> Arguments) const { 84 return PrevTTI->getIntrinsicCost(IID, RetTy, Arguments); 85 } 86 87 unsigned TargetTransformInfo::getUserCost(const User *U) const { 88 return PrevTTI->getUserCost(U); 89 } 90 91 bool TargetTransformInfo::isLoweredToCall(const Function *F) const { 92 return PrevTTI->isLoweredToCall(F); 93 } 94 95 bool TargetTransformInfo::isLegalAddImmediate(int64_t Imm) const { 96 return PrevTTI->isLegalAddImmediate(Imm); 97 } 98 99 bool TargetTransformInfo::isLegalICmpImmediate(int64_t Imm) const { 100 return PrevTTI->isLegalICmpImmediate(Imm); 101 } 102 103 bool TargetTransformInfo::isLegalAddressingMode(Type *Ty, GlobalValue *BaseGV, 104 int64_t BaseOffset, 105 bool HasBaseReg, 106 int64_t Scale) const { 107 return PrevTTI->isLegalAddressingMode(Ty, BaseGV, BaseOffset, HasBaseReg, 108 Scale); 109 } 110 111 bool TargetTransformInfo::isTruncateFree(Type *Ty1, Type *Ty2) const { 112 return PrevTTI->isTruncateFree(Ty1, Ty2); 113 } 114 115 bool TargetTransformInfo::isTypeLegal(Type *Ty) const { 116 return PrevTTI->isTypeLegal(Ty); 117 } 118 119 unsigned TargetTransformInfo::getJumpBufAlignment() const { 120 return PrevTTI->getJumpBufAlignment(); 121 } 122 123 unsigned TargetTransformInfo::getJumpBufSize() const { 124 return PrevTTI->getJumpBufSize(); 125 } 126 127 bool TargetTransformInfo::shouldBuildLookupTables() const { 128 return PrevTTI->shouldBuildLookupTables(); 129 } 130 131 TargetTransformInfo::PopcntSupportKind 132 TargetTransformInfo::getPopcntSupport(unsigned IntTyWidthInBit) const { 133 return PrevTTI->getPopcntSupport(IntTyWidthInBit); 134 } 135 136 unsigned TargetTransformInfo::getIntImmCost(const APInt &Imm, Type *Ty) const { 137 return PrevTTI->getIntImmCost(Imm, Ty); 138 } 139 140 unsigned TargetTransformInfo::getNumberOfRegisters(bool Vector) const { 141 return PrevTTI->getNumberOfRegisters(Vector); 142 } 143 144 unsigned TargetTransformInfo::getRegisterBitWidth(bool Vector) const { 145 return PrevTTI->getRegisterBitWidth(Vector); 146 } 147 148 unsigned TargetTransformInfo::getMaximumUnrollFactor() const { 149 return PrevTTI->getMaximumUnrollFactor(); 150 } 151 152 unsigned TargetTransformInfo::getArithmeticInstrCost(unsigned Opcode, 153 Type *Ty) const { 154 return PrevTTI->getArithmeticInstrCost(Opcode, Ty); 155 } 156 157 unsigned TargetTransformInfo::getShuffleCost(ShuffleKind Kind, Type *Tp, 158 int Index, Type *SubTp) const { 159 return PrevTTI->getShuffleCost(Kind, Tp, Index, SubTp); 160 } 161 162 unsigned TargetTransformInfo::getCastInstrCost(unsigned Opcode, Type *Dst, 163 Type *Src) const { 164 return PrevTTI->getCastInstrCost(Opcode, Dst, Src); 165 } 166 167 unsigned TargetTransformInfo::getCFInstrCost(unsigned Opcode) const { 168 return PrevTTI->getCFInstrCost(Opcode); 169 } 170 171 unsigned TargetTransformInfo::getCmpSelInstrCost(unsigned Opcode, Type *ValTy, 172 Type *CondTy) const { 173 return PrevTTI->getCmpSelInstrCost(Opcode, ValTy, CondTy); 174 } 175 176 unsigned TargetTransformInfo::getVectorInstrCost(unsigned Opcode, Type *Val, 177 unsigned Index) const { 178 return PrevTTI->getVectorInstrCost(Opcode, Val, Index); 179 } 180 181 unsigned TargetTransformInfo::getMemoryOpCost(unsigned Opcode, Type *Src, 182 unsigned Alignment, 183 unsigned AddressSpace) const { 184 return PrevTTI->getMemoryOpCost(Opcode, Src, Alignment, AddressSpace); 185 ; 186 } 187 188 unsigned 189 TargetTransformInfo::getIntrinsicInstrCost(Intrinsic::ID ID, 190 Type *RetTy, 191 ArrayRef<Type *> Tys) const { 192 return PrevTTI->getIntrinsicInstrCost(ID, RetTy, Tys); 193 } 194 195 unsigned TargetTransformInfo::getNumberOfParts(Type *Tp) const { 196 return PrevTTI->getNumberOfParts(Tp); 197 } 198 199 unsigned TargetTransformInfo::getAddressComputationCost(Type *Tp) const { 200 return PrevTTI->getAddressComputationCost(Tp); 201 } 202 203 namespace { 204 205 struct NoTTI : ImmutablePass, TargetTransformInfo { 206 const DataLayout *DL; 207 208 NoTTI() : ImmutablePass(ID), DL(0) { 209 initializeNoTTIPass(*PassRegistry::getPassRegistry()); 210 } 211 212 virtual void initializePass() { 213 // Note that this subclass is special, and must *not* call initializeTTI as 214 // it does not chain. 215 TopTTI = this; 216 PrevTTI = 0; 217 DL = getAnalysisIfAvailable<DataLayout>(); 218 } 219 220 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 221 // Note that this subclass is special, and must *not* call 222 // TTI::getAnalysisUsage as it breaks the recursion. 223 } 224 225 /// Pass identification. 226 static char ID; 227 228 /// Provide necessary pointer adjustments for the two base classes. 229 virtual void *getAdjustedAnalysisPointer(const void *ID) { 230 if (ID == &TargetTransformInfo::ID) 231 return (TargetTransformInfo*)this; 232 return this; 233 } 234 235 unsigned getOperationCost(unsigned Opcode, Type *Ty, Type *OpTy) const { 236 switch (Opcode) { 237 default: 238 // By default, just classify everything as 'basic'. 239 return TCC_Basic; 240 241 case Instruction::GetElementPtr: 242 llvm_unreachable("Use getGEPCost for GEP operations!"); 243 244 case Instruction::BitCast: 245 assert(OpTy && "Cast instructions must provide the operand type"); 246 if (Ty == OpTy || (Ty->isPointerTy() && OpTy->isPointerTy())) 247 // Identity and pointer-to-pointer casts are free. 248 return TCC_Free; 249 250 // Otherwise, the default basic cost is used. 251 return TCC_Basic; 252 253 case Instruction::IntToPtr: 254 // An inttoptr cast is free so long as the input is a legal integer type 255 // which doesn't contain values outside the range of a pointer. 256 if (DL && DL->isLegalInteger(OpTy->getScalarSizeInBits()) && 257 OpTy->getScalarSizeInBits() <= DL->getPointerSizeInBits()) 258 return TCC_Free; 259 260 // Otherwise it's not a no-op. 261 return TCC_Basic; 262 263 case Instruction::PtrToInt: 264 // A ptrtoint cast is free so long as the result is large enough to store 265 // the pointer, and a legal integer type. 266 if (DL && DL->isLegalInteger(Ty->getScalarSizeInBits()) && 267 Ty->getScalarSizeInBits() >= DL->getPointerSizeInBits()) 268 return TCC_Free; 269 270 // Otherwise it's not a no-op. 271 return TCC_Basic; 272 273 case Instruction::Trunc: 274 // trunc to a native type is free (assuming the target has compare and 275 // shift-right of the same width). 276 if (DL && DL->isLegalInteger(DL->getTypeSizeInBits(Ty))) 277 return TCC_Free; 278 279 return TCC_Basic; 280 } 281 } 282 283 unsigned getGEPCost(const Value *Ptr, 284 ArrayRef<const Value *> Operands) const { 285 // In the basic model, we just assume that all-constant GEPs will be folded 286 // into their uses via addressing modes. 287 for (unsigned Idx = 0, Size = Operands.size(); Idx != Size; ++Idx) 288 if (!isa<Constant>(Operands[Idx])) 289 return TCC_Basic; 290 291 return TCC_Free; 292 } 293 294 unsigned getCallCost(FunctionType *FTy, int NumArgs = -1) const { 295 assert(FTy && "FunctionType must be provided to this routine."); 296 297 // The target-independent implementation just measures the size of the 298 // function by approximating that each argument will take on average one 299 // instruction to prepare. 300 301 if (NumArgs < 0) 302 // Set the argument number to the number of explicit arguments in the 303 // function. 304 NumArgs = FTy->getNumParams(); 305 306 return TCC_Basic * (NumArgs + 1); 307 } 308 309 unsigned getCallCost(const Function *F, int NumArgs = -1) const { 310 assert(F && "A concrete function must be provided to this routine."); 311 312 if (NumArgs < 0) 313 // Set the argument number to the number of explicit arguments in the 314 // function. 315 NumArgs = F->arg_size(); 316 317 if (Intrinsic::ID IID = (Intrinsic::ID)F->getIntrinsicID()) { 318 FunctionType *FTy = F->getFunctionType(); 319 SmallVector<Type *, 8> ParamTys(FTy->param_begin(), FTy->param_end()); 320 return TopTTI->getIntrinsicCost(IID, FTy->getReturnType(), ParamTys); 321 } 322 323 if (!TopTTI->isLoweredToCall(F)) 324 return TCC_Basic; // Give a basic cost if it will be lowered directly. 325 326 return TopTTI->getCallCost(F->getFunctionType(), NumArgs); 327 } 328 329 unsigned getCallCost(const Function *F, 330 ArrayRef<const Value *> Arguments) const { 331 // Simply delegate to generic handling of the call. 332 // FIXME: We should use instsimplify or something else to catch calls which 333 // will constant fold with these arguments. 334 return TopTTI->getCallCost(F, Arguments.size()); 335 } 336 337 unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy, 338 ArrayRef<Type *> ParamTys) const { 339 switch (IID) { 340 default: 341 // Intrinsics rarely (if ever) have normal argument setup constraints. 342 // Model them as having a basic instruction cost. 343 // FIXME: This is wrong for libc intrinsics. 344 return TCC_Basic; 345 346 case Intrinsic::dbg_declare: 347 case Intrinsic::dbg_value: 348 case Intrinsic::invariant_start: 349 case Intrinsic::invariant_end: 350 case Intrinsic::lifetime_start: 351 case Intrinsic::lifetime_end: 352 case Intrinsic::objectsize: 353 case Intrinsic::ptr_annotation: 354 case Intrinsic::var_annotation: 355 // These intrinsics don't actually represent code after lowering. 356 return TCC_Free; 357 } 358 } 359 360 unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy, 361 ArrayRef<const Value *> Arguments) const { 362 // Delegate to the generic intrinsic handling code. This mostly provides an 363 // opportunity for targets to (for example) special case the cost of 364 // certain intrinsics based on constants used as arguments. 365 SmallVector<Type *, 8> ParamTys; 366 ParamTys.reserve(Arguments.size()); 367 for (unsigned Idx = 0, Size = Arguments.size(); Idx != Size; ++Idx) 368 ParamTys.push_back(Arguments[Idx]->getType()); 369 return TopTTI->getIntrinsicCost(IID, RetTy, ParamTys); 370 } 371 372 unsigned getUserCost(const User *U) const { 373 if (isa<PHINode>(U)) 374 return TCC_Free; // Model all PHI nodes as free. 375 376 if (const GEPOperator *GEP = dyn_cast<GEPOperator>(U)) 377 // In the basic model we just assume that all-constant GEPs will be 378 // folded into their uses via addressing modes. 379 return GEP->hasAllConstantIndices() ? TCC_Free : TCC_Basic; 380 381 if (ImmutableCallSite CS = U) { 382 const Function *F = CS.getCalledFunction(); 383 if (!F) { 384 // Just use the called value type. 385 Type *FTy = CS.getCalledValue()->getType()->getPointerElementType(); 386 return TopTTI->getCallCost(cast<FunctionType>(FTy), CS.arg_size()); 387 } 388 389 SmallVector<const Value *, 8> Arguments; 390 for (ImmutableCallSite::arg_iterator AI = CS.arg_begin(), 391 AE = CS.arg_end(); 392 AI != AE; ++AI) 393 Arguments.push_back(*AI); 394 395 return TopTTI->getCallCost(F, Arguments); 396 } 397 398 if (const CastInst *CI = dyn_cast<CastInst>(U)) { 399 // Result of a cmp instruction is often extended (to be used by other 400 // cmp instructions, logical or return instructions). These are usually 401 // nop on most sane targets. 402 if (isa<CmpInst>(CI->getOperand(0))) 403 return TCC_Free; 404 } 405 406 // Otherwise delegate to the fully generic implementations. 407 return getOperationCost(Operator::getOpcode(U), U->getType(), 408 U->getNumOperands() == 1 ? 409 U->getOperand(0)->getType() : 0); 410 } 411 412 bool isLoweredToCall(const Function *F) const { 413 // FIXME: These should almost certainly not be handled here, and instead 414 // handled with the help of TLI or the target itself. This was largely 415 // ported from existing analysis heuristics here so that such refactorings 416 // can take place in the future. 417 418 if (F->isIntrinsic()) 419 return false; 420 421 if (F->hasLocalLinkage() || !F->hasName()) 422 return true; 423 424 StringRef Name = F->getName(); 425 426 // These will all likely lower to a single selection DAG node. 427 if (Name == "copysign" || Name == "copysignf" || Name == "copysignl" || 428 Name == "fabs" || Name == "fabsf" || Name == "fabsl" || Name == "sin" || 429 Name == "sinf" || Name == "sinl" || Name == "cos" || Name == "cosf" || 430 Name == "cosl" || Name == "sqrt" || Name == "sqrtf" || Name == "sqrtl") 431 return false; 432 433 // These are all likely to be optimized into something smaller. 434 if (Name == "pow" || Name == "powf" || Name == "powl" || Name == "exp2" || 435 Name == "exp2l" || Name == "exp2f" || Name == "floor" || Name == 436 "floorf" || Name == "ceil" || Name == "round" || Name == "ffs" || 437 Name == "ffsl" || Name == "abs" || Name == "labs" || Name == "llabs") 438 return false; 439 440 return true; 441 } 442 443 bool isLegalAddImmediate(int64_t Imm) const { 444 return false; 445 } 446 447 bool isLegalICmpImmediate(int64_t Imm) const { 448 return false; 449 } 450 451 bool isLegalAddressingMode(Type *Ty, GlobalValue *BaseGV, int64_t BaseOffset, 452 bool HasBaseReg, int64_t Scale) const { 453 // Guess that reg+reg addressing is allowed. This heuristic is taken from 454 // the implementation of LSR. 455 return !BaseGV && BaseOffset == 0 && Scale <= 1; 456 } 457 458 bool isTruncateFree(Type *Ty1, Type *Ty2) const { 459 return false; 460 } 461 462 bool isTypeLegal(Type *Ty) const { 463 return false; 464 } 465 466 unsigned getJumpBufAlignment() const { 467 return 0; 468 } 469 470 unsigned getJumpBufSize() const { 471 return 0; 472 } 473 474 bool shouldBuildLookupTables() const { 475 return true; 476 } 477 478 PopcntSupportKind getPopcntSupport(unsigned IntTyWidthInBit) const { 479 return PSK_Software; 480 } 481 482 unsigned getIntImmCost(const APInt &Imm, Type *Ty) const { 483 return 1; 484 } 485 486 unsigned getNumberOfRegisters(bool Vector) const { 487 return 8; 488 } 489 490 unsigned getRegisterBitWidth(bool Vector) const { 491 return 32; 492 } 493 494 unsigned getMaximumUnrollFactor() const { 495 return 1; 496 } 497 498 unsigned getArithmeticInstrCost(unsigned Opcode, Type *Ty) const { 499 return 1; 500 } 501 502 unsigned getShuffleCost(ShuffleKind Kind, Type *Tp, 503 int Index = 0, Type *SubTp = 0) const { 504 return 1; 505 } 506 507 unsigned getCastInstrCost(unsigned Opcode, Type *Dst, 508 Type *Src) const { 509 return 1; 510 } 511 512 unsigned getCFInstrCost(unsigned Opcode) const { 513 return 1; 514 } 515 516 unsigned getCmpSelInstrCost(unsigned Opcode, Type *ValTy, 517 Type *CondTy = 0) const { 518 return 1; 519 } 520 521 unsigned getVectorInstrCost(unsigned Opcode, Type *Val, 522 unsigned Index = -1) const { 523 return 1; 524 } 525 526 unsigned getMemoryOpCost(unsigned Opcode, Type *Src, 527 unsigned Alignment, 528 unsigned AddressSpace) const { 529 return 1; 530 } 531 532 unsigned getIntrinsicInstrCost(Intrinsic::ID ID, 533 Type *RetTy, 534 ArrayRef<Type*> Tys) const { 535 return 1; 536 } 537 538 unsigned getNumberOfParts(Type *Tp) const { 539 return 0; 540 } 541 542 unsigned getAddressComputationCost(Type *Tp) const { 543 return 0; 544 } 545 }; 546 547 } // end anonymous namespace 548 549 INITIALIZE_AG_PASS(NoTTI, TargetTransformInfo, "notti", 550 "No target information", true, true, true) 551 char NoTTI::ID = 0; 552 553 ImmutablePass *llvm::createNoTargetTransformInfoPass() { 554 return new NoTTI(); 555 } 556