BasicTargetTransformInfo.cpp revision 6bf4f676413b8f7d97aaff289997aab344180957
1//===- BasicTargetTransformInfo.cpp - Basic target-independent TTI impl ---===// 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/// \file 10/// This file provides the implementation of a basic TargetTransformInfo pass 11/// predicated on the target abstractions present in the target independent 12/// code generator. It uses these (primarily TargetLowering) to model as much 13/// of the TTI query interface as possible. It is included by most targets so 14/// that they can specialize only a small subset of the query space. 15/// 16//===----------------------------------------------------------------------===// 17 18#define DEBUG_TYPE "basictti" 19#include "llvm/CodeGen/Passes.h" 20#include "llvm/Analysis/TargetTransformInfo.h" 21#include "llvm/Target/TargetLowering.h" 22#include <utility> 23 24using namespace llvm; 25 26namespace { 27 28class BasicTTI : public ImmutablePass, public TargetTransformInfo { 29 const TargetLoweringBase *TLI; 30 31 /// Estimate the overhead of scalarizing an instruction. Insert and Extract 32 /// are set if the result needs to be inserted and/or extracted from vectors. 33 unsigned getScalarizationOverhead(Type *Ty, bool Insert, bool Extract) const; 34 35public: 36 BasicTTI() : ImmutablePass(ID), TLI(0) { 37 llvm_unreachable("This pass cannot be directly constructed"); 38 } 39 40 BasicTTI(const TargetLoweringBase *TLI) : ImmutablePass(ID), TLI(TLI) { 41 initializeBasicTTIPass(*PassRegistry::getPassRegistry()); 42 } 43 44 virtual void initializePass() { 45 pushTTIStack(this); 46 } 47 48 virtual void finalizePass() { 49 popTTIStack(); 50 } 51 52 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 53 TargetTransformInfo::getAnalysisUsage(AU); 54 } 55 56 /// Pass identification. 57 static char ID; 58 59 /// Provide necessary pointer adjustments for the two base classes. 60 virtual void *getAdjustedAnalysisPointer(const void *ID) { 61 if (ID == &TargetTransformInfo::ID) 62 return (TargetTransformInfo*)this; 63 return this; 64 } 65 66 /// \name Scalar TTI Implementations 67 /// @{ 68 69 virtual bool isLegalAddImmediate(int64_t imm) const; 70 virtual bool isLegalICmpImmediate(int64_t imm) const; 71 virtual bool isLegalAddressingMode(Type *Ty, GlobalValue *BaseGV, 72 int64_t BaseOffset, bool HasBaseReg, 73 int64_t Scale) const; 74 virtual bool isTruncateFree(Type *Ty1, Type *Ty2) const; 75 virtual bool isTypeLegal(Type *Ty) const; 76 virtual unsigned getJumpBufAlignment() const; 77 virtual unsigned getJumpBufSize() const; 78 virtual bool shouldBuildLookupTables() const; 79 80 /// @} 81 82 /// \name Vector TTI Implementations 83 /// @{ 84 85 virtual unsigned getNumberOfRegisters(bool Vector) const; 86 virtual unsigned getMaximumUnrollFactor() const; 87 virtual unsigned getRegisterBitWidth(bool Vector) const; 88 virtual unsigned getArithmeticInstrCost(unsigned Opcode, Type *Ty, 89 OperandValueKind, 90 OperandValueKind) const; 91 virtual unsigned getShuffleCost(ShuffleKind Kind, Type *Tp, 92 int Index, Type *SubTp) const; 93 virtual unsigned getCastInstrCost(unsigned Opcode, Type *Dst, 94 Type *Src) const; 95 virtual unsigned getCFInstrCost(unsigned Opcode) const; 96 virtual unsigned getCmpSelInstrCost(unsigned Opcode, Type *ValTy, 97 Type *CondTy) const; 98 virtual unsigned getVectorInstrCost(unsigned Opcode, Type *Val, 99 unsigned Index) const; 100 virtual unsigned getMemoryOpCost(unsigned Opcode, Type *Src, 101 unsigned Alignment, 102 unsigned AddressSpace) const; 103 virtual unsigned getIntrinsicInstrCost(Intrinsic::ID, Type *RetTy, 104 ArrayRef<Type*> Tys) const; 105 virtual unsigned getNumberOfParts(Type *Tp) const; 106 virtual unsigned getAddressComputationCost(Type *Ty) const; 107 108 /// @} 109}; 110 111} 112 113INITIALIZE_AG_PASS(BasicTTI, TargetTransformInfo, "basictti", 114 "Target independent code generator's TTI", true, true, false) 115char BasicTTI::ID = 0; 116 117ImmutablePass * 118llvm::createBasicTargetTransformInfoPass(const TargetLoweringBase *TLI) { 119 return new BasicTTI(TLI); 120} 121 122 123bool BasicTTI::isLegalAddImmediate(int64_t imm) const { 124 return TLI->isLegalAddImmediate(imm); 125} 126 127bool BasicTTI::isLegalICmpImmediate(int64_t imm) const { 128 return TLI->isLegalICmpImmediate(imm); 129} 130 131bool BasicTTI::isLegalAddressingMode(Type *Ty, GlobalValue *BaseGV, 132 int64_t BaseOffset, bool HasBaseReg, 133 int64_t Scale) const { 134 TargetLoweringBase::AddrMode AM; 135 AM.BaseGV = BaseGV; 136 AM.BaseOffs = BaseOffset; 137 AM.HasBaseReg = HasBaseReg; 138 AM.Scale = Scale; 139 return TLI->isLegalAddressingMode(AM, Ty); 140} 141 142bool BasicTTI::isTruncateFree(Type *Ty1, Type *Ty2) const { 143 return TLI->isTruncateFree(Ty1, Ty2); 144} 145 146bool BasicTTI::isTypeLegal(Type *Ty) const { 147 EVT T = TLI->getValueType(Ty); 148 return TLI->isTypeLegal(T); 149} 150 151unsigned BasicTTI::getJumpBufAlignment() const { 152 return TLI->getJumpBufAlignment(); 153} 154 155unsigned BasicTTI::getJumpBufSize() const { 156 return TLI->getJumpBufSize(); 157} 158 159bool BasicTTI::shouldBuildLookupTables() const { 160 return TLI->supportJumpTables() && 161 (TLI->isOperationLegalOrCustom(ISD::BR_JT, MVT::Other) || 162 TLI->isOperationLegalOrCustom(ISD::BRIND, MVT::Other)); 163} 164 165//===----------------------------------------------------------------------===// 166// 167// Calls used by the vectorizers. 168// 169//===----------------------------------------------------------------------===// 170 171unsigned BasicTTI::getScalarizationOverhead(Type *Ty, bool Insert, 172 bool Extract) const { 173 assert (Ty->isVectorTy() && "Can only scalarize vectors"); 174 unsigned Cost = 0; 175 176 for (int i = 0, e = Ty->getVectorNumElements(); i < e; ++i) { 177 if (Insert) 178 Cost += TopTTI->getVectorInstrCost(Instruction::InsertElement, Ty, i); 179 if (Extract) 180 Cost += TopTTI->getVectorInstrCost(Instruction::ExtractElement, Ty, i); 181 } 182 183 return Cost; 184} 185 186unsigned BasicTTI::getNumberOfRegisters(bool Vector) const { 187 return 1; 188} 189 190unsigned BasicTTI::getRegisterBitWidth(bool Vector) const { 191 return 32; 192} 193 194unsigned BasicTTI::getMaximumUnrollFactor() const { 195 return 1; 196} 197 198unsigned BasicTTI::getArithmeticInstrCost(unsigned Opcode, Type *Ty, 199 OperandValueKind, 200 OperandValueKind) const { 201 // Check if any of the operands are vector operands. 202 int ISD = TLI->InstructionOpcodeToISD(Opcode); 203 assert(ISD && "Invalid opcode"); 204 205 std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Ty); 206 207 if (TLI->isOperationLegalOrPromote(ISD, LT.second)) { 208 // The operation is legal. Assume it costs 1. 209 // If the type is split to multiple registers, assume that thre is some 210 // overhead to this. 211 // TODO: Once we have extract/insert subvector cost we need to use them. 212 if (LT.first > 1) 213 return LT.first * 2; 214 return LT.first * 1; 215 } 216 217 if (!TLI->isOperationExpand(ISD, LT.second)) { 218 // If the operation is custom lowered then assume 219 // thare the code is twice as expensive. 220 return LT.first * 2; 221 } 222 223 // Else, assume that we need to scalarize this op. 224 if (Ty->isVectorTy()) { 225 unsigned Num = Ty->getVectorNumElements(); 226 unsigned Cost = TopTTI->getArithmeticInstrCost(Opcode, Ty->getScalarType()); 227 // return the cost of multiple scalar invocation plus the cost of inserting 228 // and extracting the values. 229 return getScalarizationOverhead(Ty, true, true) + Num * Cost; 230 } 231 232 // We don't know anything about this scalar instruction. 233 return 1; 234} 235 236unsigned BasicTTI::getShuffleCost(ShuffleKind Kind, Type *Tp, int Index, 237 Type *SubTp) const { 238 return 1; 239} 240 241unsigned BasicTTI::getCastInstrCost(unsigned Opcode, Type *Dst, 242 Type *Src) const { 243 int ISD = TLI->InstructionOpcodeToISD(Opcode); 244 assert(ISD && "Invalid opcode"); 245 246 std::pair<unsigned, MVT> SrcLT = TLI->getTypeLegalizationCost(Src); 247 std::pair<unsigned, MVT> DstLT = TLI->getTypeLegalizationCost(Dst); 248 249 // Check for NOOP conversions. 250 if (SrcLT.first == DstLT.first && 251 SrcLT.second.getSizeInBits() == DstLT.second.getSizeInBits()) { 252 253 // Bitcast between types that are legalized to the same type are free. 254 if (Opcode == Instruction::BitCast || Opcode == Instruction::Trunc) 255 return 0; 256 } 257 258 if (Opcode == Instruction::Trunc && 259 TLI->isTruncateFree(SrcLT.second, DstLT.second)) 260 return 0; 261 262 if (Opcode == Instruction::ZExt && 263 TLI->isZExtFree(SrcLT.second, DstLT.second)) 264 return 0; 265 266 // If the cast is marked as legal (or promote) then assume low cost. 267 if (TLI->isOperationLegalOrPromote(ISD, DstLT.second)) 268 return 1; 269 270 // Handle scalar conversions. 271 if (!Src->isVectorTy() && !Dst->isVectorTy()) { 272 273 // Scalar bitcasts are usually free. 274 if (Opcode == Instruction::BitCast) 275 return 0; 276 277 // Just check the op cost. If the operation is legal then assume it costs 1. 278 if (!TLI->isOperationExpand(ISD, DstLT.second)) 279 return 1; 280 281 // Assume that illegal scalar instruction are expensive. 282 return 4; 283 } 284 285 // Check vector-to-vector casts. 286 if (Dst->isVectorTy() && Src->isVectorTy()) { 287 288 // If the cast is between same-sized registers, then the check is simple. 289 if (SrcLT.first == DstLT.first && 290 SrcLT.second.getSizeInBits() == DstLT.second.getSizeInBits()) { 291 292 // Assume that Zext is done using AND. 293 if (Opcode == Instruction::ZExt) 294 return 1; 295 296 // Assume that sext is done using SHL and SRA. 297 if (Opcode == Instruction::SExt) 298 return 2; 299 300 // Just check the op cost. If the operation is legal then assume it costs 301 // 1 and multiply by the type-legalization overhead. 302 if (!TLI->isOperationExpand(ISD, DstLT.second)) 303 return SrcLT.first * 1; 304 } 305 306 // If we are converting vectors and the operation is illegal, or 307 // if the vectors are legalized to different types, estimate the 308 // scalarization costs. 309 unsigned Num = Dst->getVectorNumElements(); 310 unsigned Cost = TopTTI->getCastInstrCost(Opcode, Dst->getScalarType(), 311 Src->getScalarType()); 312 313 // Return the cost of multiple scalar invocation plus the cost of 314 // inserting and extracting the values. 315 return getScalarizationOverhead(Dst, true, true) + Num * Cost; 316 } 317 318 // We already handled vector-to-vector and scalar-to-scalar conversions. This 319 // is where we handle bitcast between vectors and scalars. We need to assume 320 // that the conversion is scalarized in one way or another. 321 if (Opcode == Instruction::BitCast) 322 // Illegal bitcasts are done by storing and loading from a stack slot. 323 return (Src->isVectorTy()? getScalarizationOverhead(Src, false, true):0) + 324 (Dst->isVectorTy()? getScalarizationOverhead(Dst, true, false):0); 325 326 llvm_unreachable("Unhandled cast"); 327 } 328 329unsigned BasicTTI::getCFInstrCost(unsigned Opcode) const { 330 // Branches are assumed to be predicted. 331 return 0; 332} 333 334unsigned BasicTTI::getCmpSelInstrCost(unsigned Opcode, Type *ValTy, 335 Type *CondTy) const { 336 int ISD = TLI->InstructionOpcodeToISD(Opcode); 337 assert(ISD && "Invalid opcode"); 338 339 // Selects on vectors are actually vector selects. 340 if (ISD == ISD::SELECT) { 341 assert(CondTy && "CondTy must exist"); 342 if (CondTy->isVectorTy()) 343 ISD = ISD::VSELECT; 344 } 345 346 std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(ValTy); 347 348 if (!TLI->isOperationExpand(ISD, LT.second)) { 349 // The operation is legal. Assume it costs 1. Multiply 350 // by the type-legalization overhead. 351 return LT.first * 1; 352 } 353 354 // Otherwise, assume that the cast is scalarized. 355 if (ValTy->isVectorTy()) { 356 unsigned Num = ValTy->getVectorNumElements(); 357 if (CondTy) 358 CondTy = CondTy->getScalarType(); 359 unsigned Cost = TopTTI->getCmpSelInstrCost(Opcode, ValTy->getScalarType(), 360 CondTy); 361 362 // Return the cost of multiple scalar invocation plus the cost of inserting 363 // and extracting the values. 364 return getScalarizationOverhead(ValTy, true, false) + Num * Cost; 365 } 366 367 // Unknown scalar opcode. 368 return 1; 369} 370 371unsigned BasicTTI::getVectorInstrCost(unsigned Opcode, Type *Val, 372 unsigned Index) const { 373 return 1; 374} 375 376unsigned BasicTTI::getMemoryOpCost(unsigned Opcode, Type *Src, 377 unsigned Alignment, 378 unsigned AddressSpace) const { 379 assert(!Src->isVoidTy() && "Invalid type"); 380 std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Src); 381 382 // Assume that all loads of legal types cost 1. 383 return LT.first; 384} 385 386unsigned BasicTTI::getIntrinsicInstrCost(Intrinsic::ID IID, Type *RetTy, 387 ArrayRef<Type *> Tys) const { 388 unsigned ISD = 0; 389 switch (IID) { 390 default: { 391 // Assume that we need to scalarize this intrinsic. 392 unsigned ScalarizationCost = 0; 393 unsigned ScalarCalls = 1; 394 if (RetTy->isVectorTy()) { 395 ScalarizationCost = getScalarizationOverhead(RetTy, true, false); 396 ScalarCalls = std::max(ScalarCalls, RetTy->getVectorNumElements()); 397 } 398 for (unsigned i = 0, ie = Tys.size(); i != ie; ++i) { 399 if (Tys[i]->isVectorTy()) { 400 ScalarizationCost += getScalarizationOverhead(Tys[i], false, true); 401 ScalarCalls = std::max(ScalarCalls, RetTy->getVectorNumElements()); 402 } 403 } 404 405 return ScalarCalls + ScalarizationCost; 406 } 407 // Look for intrinsics that can be lowered directly or turned into a scalar 408 // intrinsic call. 409 case Intrinsic::sqrt: ISD = ISD::FSQRT; break; 410 case Intrinsic::sin: ISD = ISD::FSIN; break; 411 case Intrinsic::cos: ISD = ISD::FCOS; break; 412 case Intrinsic::exp: ISD = ISD::FEXP; break; 413 case Intrinsic::exp2: ISD = ISD::FEXP2; break; 414 case Intrinsic::log: ISD = ISD::FLOG; break; 415 case Intrinsic::log10: ISD = ISD::FLOG10; break; 416 case Intrinsic::log2: ISD = ISD::FLOG2; break; 417 case Intrinsic::fabs: ISD = ISD::FABS; break; 418 case Intrinsic::floor: ISD = ISD::FFLOOR; break; 419 case Intrinsic::ceil: ISD = ISD::FCEIL; break; 420 case Intrinsic::trunc: ISD = ISD::FTRUNC; break; 421 case Intrinsic::rint: ISD = ISD::FRINT; break; 422 case Intrinsic::pow: ISD = ISD::FPOW; break; 423 case Intrinsic::fma: ISD = ISD::FMA; break; 424 case Intrinsic::fmuladd: ISD = ISD::FMA; break; // FIXME: mul + add? 425 } 426 427 std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(RetTy); 428 429 if (TLI->isOperationLegalOrPromote(ISD, LT.second)) { 430 // The operation is legal. Assume it costs 1. 431 // If the type is split to multiple registers, assume that thre is some 432 // overhead to this. 433 // TODO: Once we have extract/insert subvector cost we need to use them. 434 if (LT.first > 1) 435 return LT.first * 2; 436 return LT.first * 1; 437 } 438 439 if (!TLI->isOperationExpand(ISD, LT.second)) { 440 // If the operation is custom lowered then assume 441 // thare the code is twice as expensive. 442 return LT.first * 2; 443 } 444 445 // Else, assume that we need to scalarize this intrinsic. For math builtins 446 // this will emit a costly libcall, adding call overhead and spills. Make it 447 // very expensive. 448 if (RetTy->isVectorTy()) { 449 unsigned Num = RetTy->getVectorNumElements(); 450 unsigned Cost = TopTTI->getIntrinsicInstrCost(IID, RetTy->getScalarType(), 451 Tys); 452 return 10 * Cost * Num; 453 } 454 455 // This is going to be turned into a library call, make it expensive. 456 return 10; 457} 458 459unsigned BasicTTI::getNumberOfParts(Type *Tp) const { 460 std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Tp); 461 return LT.first; 462} 463 464unsigned BasicTTI::getAddressComputationCost(Type *Ty) const { 465 return 0; 466} 467