TargetTransformInfo.cpp revision 263508 
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
20using namespace llvm;
21
22// Setup the analysis group to manage the TargetTransformInfo passes.
23INITIALIZE_ANALYSIS_GROUP(TargetTransformInfo, "Target Information", NoTTI)
24char TargetTransformInfo::ID = 0;
25
26TargetTransformInfo::~TargetTransformInfo() {
27}
28
29void 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
38void 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
48void TargetTransformInfo::getAnalysisUsage(AnalysisUsage &AU) const {
49  AU.addRequired<TargetTransformInfo>();
50}
51
52unsigned TargetTransformInfo::getOperationCost(unsigned Opcode, Type *Ty,
53                                               Type *OpTy) const {
54  return PrevTTI->getOperationCost(Opcode, Ty, OpTy);
55}
56
57unsigned TargetTransformInfo::getGEPCost(
58    const Value *Ptr, ArrayRef<const Value *> Operands) const {
59  return PrevTTI->getGEPCost(Ptr, Operands);
60}
61
62unsigned TargetTransformInfo::getCallCost(FunctionType *FTy,
63                                          int NumArgs) const {
64  return PrevTTI->getCallCost(FTy, NumArgs);
65}
66
67unsigned TargetTransformInfo::getCallCost(const Function *F,
68                                          int NumArgs) const {
69  return PrevTTI->getCallCost(F, NumArgs);
70}
71
72unsigned TargetTransformInfo::getCallCost(
73    const Function *F, ArrayRef<const Value *> Arguments) const {
74  return PrevTTI->getCallCost(F, Arguments);
75}
76
77unsigned TargetTransformInfo::getIntrinsicCost(
78    Intrinsic::ID IID, Type *RetTy, ArrayRef<Type *> ParamTys) const {
79  return PrevTTI->getIntrinsicCost(IID, RetTy, ParamTys);
80}
81
82unsigned TargetTransformInfo::getIntrinsicCost(
83    Intrinsic::ID IID, Type *RetTy, ArrayRef<const Value *> Arguments) const {
84  return PrevTTI->getIntrinsicCost(IID, RetTy, Arguments);
85}
86
87unsigned TargetTransformInfo::getUserCost(const User *U) const {
88  return PrevTTI->getUserCost(U);
89}
90
91bool TargetTransformInfo::hasBranchDivergence() const {
92  return PrevTTI->hasBranchDivergence();
93}
94
95bool TargetTransformInfo::isLoweredToCall(const Function *F) const {
96  return PrevTTI->isLoweredToCall(F);
97}
98
99void TargetTransformInfo::getUnrollingPreferences(Loop *L,
100                            UnrollingPreferences &UP) const {
101  PrevTTI->getUnrollingPreferences(L, UP);
102}
103
104bool TargetTransformInfo::isLegalAddImmediate(int64_t Imm) const {
105  return PrevTTI->isLegalAddImmediate(Imm);
106}
107
108bool TargetTransformInfo::isLegalICmpImmediate(int64_t Imm) const {
109  return PrevTTI->isLegalICmpImmediate(Imm);
110}
111
112bool TargetTransformInfo::isLegalAddressingMode(Type *Ty, GlobalValue *BaseGV,
113                                                int64_t BaseOffset,
114                                                bool HasBaseReg,
115                                                int64_t Scale) const {
116  return PrevTTI->isLegalAddressingMode(Ty, BaseGV, BaseOffset, HasBaseReg,
117                                        Scale);
118}
119
120int TargetTransformInfo::getScalingFactorCost(Type *Ty, GlobalValue *BaseGV,
121                                              int64_t BaseOffset,
122                                              bool HasBaseReg,
123                                              int64_t Scale) const {
124  return PrevTTI->getScalingFactorCost(Ty, BaseGV, BaseOffset, HasBaseReg,
125                                       Scale);
126}
127
128bool TargetTransformInfo::isTruncateFree(Type *Ty1, Type *Ty2) const {
129  return PrevTTI->isTruncateFree(Ty1, Ty2);
130}
131
132bool TargetTransformInfo::isTypeLegal(Type *Ty) const {
133  return PrevTTI->isTypeLegal(Ty);
134}
135
136unsigned TargetTransformInfo::getJumpBufAlignment() const {
137  return PrevTTI->getJumpBufAlignment();
138}
139
140unsigned TargetTransformInfo::getJumpBufSize() const {
141  return PrevTTI->getJumpBufSize();
142}
143
144bool TargetTransformInfo::shouldBuildLookupTables() const {
145  return PrevTTI->shouldBuildLookupTables();
146}
147
148TargetTransformInfo::PopcntSupportKind
149TargetTransformInfo::getPopcntSupport(unsigned IntTyWidthInBit) const {
150  return PrevTTI->getPopcntSupport(IntTyWidthInBit);
151}
152
153bool TargetTransformInfo::haveFastSqrt(Type *Ty) const {
154  return PrevTTI->haveFastSqrt(Ty);
155}
156
157unsigned TargetTransformInfo::getIntImmCost(const APInt &Imm, Type *Ty) const {
158  return PrevTTI->getIntImmCost(Imm, Ty);
159}
160
161unsigned TargetTransformInfo::getNumberOfRegisters(bool Vector) const {
162  return PrevTTI->getNumberOfRegisters(Vector);
163}
164
165unsigned TargetTransformInfo::getRegisterBitWidth(bool Vector) const {
166  return PrevTTI->getRegisterBitWidth(Vector);
167}
168
169unsigned TargetTransformInfo::getMaximumUnrollFactor() const {
170  return PrevTTI->getMaximumUnrollFactor();
171}
172
173unsigned TargetTransformInfo::getArithmeticInstrCost(unsigned Opcode,
174                                                Type *Ty,
175                                                OperandValueKind Op1Info,
176                                                OperandValueKind Op2Info) const {
177  return PrevTTI->getArithmeticInstrCost(Opcode, Ty, Op1Info, Op2Info);
178}
179
180unsigned TargetTransformInfo::getShuffleCost(ShuffleKind Kind, Type *Tp,
181                                             int Index, Type *SubTp) const {
182  return PrevTTI->getShuffleCost(Kind, Tp, Index, SubTp);
183}
184
185unsigned TargetTransformInfo::getCastInstrCost(unsigned Opcode, Type *Dst,
186                                               Type *Src) const {
187  return PrevTTI->getCastInstrCost(Opcode, Dst, Src);
188}
189
190unsigned TargetTransformInfo::getCFInstrCost(unsigned Opcode) const {
191  return PrevTTI->getCFInstrCost(Opcode);
192}
193
194unsigned TargetTransformInfo::getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
195                                                 Type *CondTy) const {
196  return PrevTTI->getCmpSelInstrCost(Opcode, ValTy, CondTy);
197}
198
199unsigned TargetTransformInfo::getVectorInstrCost(unsigned Opcode, Type *Val,
200                                                 unsigned Index) const {
201  return PrevTTI->getVectorInstrCost(Opcode, Val, Index);
202}
203
204unsigned TargetTransformInfo::getMemoryOpCost(unsigned Opcode, Type *Src,
205                                              unsigned Alignment,
206                                              unsigned AddressSpace) const {
207  return PrevTTI->getMemoryOpCost(Opcode, Src, Alignment, AddressSpace);
208  ;
209}
210
211unsigned
212TargetTransformInfo::getIntrinsicInstrCost(Intrinsic::ID ID,
213                                           Type *RetTy,
214                                           ArrayRef<Type *> Tys) const {
215  return PrevTTI->getIntrinsicInstrCost(ID, RetTy, Tys);
216}
217
218unsigned TargetTransformInfo::getNumberOfParts(Type *Tp) const {
219  return PrevTTI->getNumberOfParts(Tp);
220}
221
222unsigned TargetTransformInfo::getAddressComputationCost(Type *Tp,
223                                                        bool IsComplex) const {
224  return PrevTTI->getAddressComputationCost(Tp, IsComplex);
225}
226
227unsigned TargetTransformInfo::getReductionCost(unsigned Opcode, Type *Ty,
228                                               bool IsPairwise) const {
229  return PrevTTI->getReductionCost(Opcode, Ty, IsPairwise);
230}
231
232namespace {
233
234struct NoTTI : ImmutablePass, TargetTransformInfo {
235  const DataLayout *DL;
236
237  NoTTI() : ImmutablePass(ID), DL(0) {
238    initializeNoTTIPass(*PassRegistry::getPassRegistry());
239  }
240
241  virtual void initializePass() {
242    // Note that this subclass is special, and must *not* call initializeTTI as
243    // it does not chain.
244    TopTTI = this;
245    PrevTTI = 0;
246    DL = getAnalysisIfAvailable<DataLayout>();
247  }
248
249  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
250    // Note that this subclass is special, and must *not* call
251    // TTI::getAnalysisUsage as it breaks the recursion.
252  }
253
254  /// Pass identification.
255  static char ID;
256
257  /// Provide necessary pointer adjustments for the two base classes.
258  virtual void *getAdjustedAnalysisPointer(const void *ID) {
259    if (ID == &TargetTransformInfo::ID)
260      return (TargetTransformInfo*)this;
261    return this;
262  }
263
264  unsigned getOperationCost(unsigned Opcode, Type *Ty, Type *OpTy) const {
265    switch (Opcode) {
266    default:
267      // By default, just classify everything as 'basic'.
268      return TCC_Basic;
269
270    case Instruction::GetElementPtr:
271      llvm_unreachable("Use getGEPCost for GEP operations!");
272
273    case Instruction::BitCast:
274      assert(OpTy && "Cast instructions must provide the operand type");
275      if (Ty == OpTy || (Ty->isPointerTy() && OpTy->isPointerTy()))
276        // Identity and pointer-to-pointer casts are free.
277        return TCC_Free;
278
279      // Otherwise, the default basic cost is used.
280      return TCC_Basic;
281
282    case Instruction::IntToPtr: {
283      if (!DL)
284        return TCC_Basic;
285
286      // An inttoptr cast is free so long as the input is a legal integer type
287      // which doesn't contain values outside the range of a pointer.
288      unsigned OpSize = OpTy->getScalarSizeInBits();
289      if (DL->isLegalInteger(OpSize) &&
290          OpSize <= DL->getPointerTypeSizeInBits(Ty))
291        return TCC_Free;
292
293      // Otherwise it's not a no-op.
294      return TCC_Basic;
295    }
296    case Instruction::PtrToInt: {
297      if (!DL)
298        return TCC_Basic;
299
300      // A ptrtoint cast is free so long as the result is large enough to store
301      // the pointer, and a legal integer type.
302      unsigned DestSize = Ty->getScalarSizeInBits();
303      if (DL->isLegalInteger(DestSize) &&
304          DestSize >= DL->getPointerTypeSizeInBits(OpTy))
305        return TCC_Free;
306
307      // Otherwise it's not a no-op.
308      return TCC_Basic;
309    }
310    case Instruction::Trunc:
311      // trunc to a native type is free (assuming the target has compare and
312      // shift-right of the same width).
313      if (DL && DL->isLegalInteger(DL->getTypeSizeInBits(Ty)))
314        return TCC_Free;
315
316      return TCC_Basic;
317    }
318  }
319
320  unsigned getGEPCost(const Value *Ptr,
321                      ArrayRef<const Value *> Operands) const {
322    // In the basic model, we just assume that all-constant GEPs will be folded
323    // into their uses via addressing modes.
324    for (unsigned Idx = 0, Size = Operands.size(); Idx != Size; ++Idx)
325      if (!isa<Constant>(Operands[Idx]))
326        return TCC_Basic;
327
328    return TCC_Free;
329  }
330
331  unsigned getCallCost(FunctionType *FTy, int NumArgs = -1) const {
332    assert(FTy && "FunctionType must be provided to this routine.");
333
334    // The target-independent implementation just measures the size of the
335    // function by approximating that each argument will take on average one
336    // instruction to prepare.
337
338    if (NumArgs < 0)
339      // Set the argument number to the number of explicit arguments in the
340      // function.
341      NumArgs = FTy->getNumParams();
342
343    return TCC_Basic * (NumArgs + 1);
344  }
345
346  unsigned getCallCost(const Function *F, int NumArgs = -1) const {
347    assert(F && "A concrete function must be provided to this routine.");
348
349    if (NumArgs < 0)
350      // Set the argument number to the number of explicit arguments in the
351      // function.
352      NumArgs = F->arg_size();
353
354    if (Intrinsic::ID IID = (Intrinsic::ID)F->getIntrinsicID()) {
355      FunctionType *FTy = F->getFunctionType();
356      SmallVector<Type *, 8> ParamTys(FTy->param_begin(), FTy->param_end());
357      return TopTTI->getIntrinsicCost(IID, FTy->getReturnType(), ParamTys);
358    }
359
360    if (!TopTTI->isLoweredToCall(F))
361      return TCC_Basic; // Give a basic cost if it will be lowered directly.
362
363    return TopTTI->getCallCost(F->getFunctionType(), NumArgs);
364  }
365
366  unsigned getCallCost(const Function *F,
367                       ArrayRef<const Value *> Arguments) const {
368    // Simply delegate to generic handling of the call.
369    // FIXME: We should use instsimplify or something else to catch calls which
370    // will constant fold with these arguments.
371    return TopTTI->getCallCost(F, Arguments.size());
372  }
373
374  unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy,
375                            ArrayRef<Type *> ParamTys) const {
376    switch (IID) {
377    default:
378      // Intrinsics rarely (if ever) have normal argument setup constraints.
379      // Model them as having a basic instruction cost.
380      // FIXME: This is wrong for libc intrinsics.
381      return TCC_Basic;
382
383    case Intrinsic::dbg_declare:
384    case Intrinsic::dbg_value:
385    case Intrinsic::invariant_start:
386    case Intrinsic::invariant_end:
387    case Intrinsic::lifetime_start:
388    case Intrinsic::lifetime_end:
389    case Intrinsic::objectsize:
390    case Intrinsic::ptr_annotation:
391    case Intrinsic::var_annotation:
392      // These intrinsics don't actually represent code after lowering.
393      return TCC_Free;
394    }
395  }
396
397  unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy,
398                            ArrayRef<const Value *> Arguments) const {
399    // Delegate to the generic intrinsic handling code. This mostly provides an
400    // opportunity for targets to (for example) special case the cost of
401    // certain intrinsics based on constants used as arguments.
402    SmallVector<Type *, 8> ParamTys;
403    ParamTys.reserve(Arguments.size());
404    for (unsigned Idx = 0, Size = Arguments.size(); Idx != Size; ++Idx)
405      ParamTys.push_back(Arguments[Idx]->getType());
406    return TopTTI->getIntrinsicCost(IID, RetTy, ParamTys);
407  }
408
409  unsigned getUserCost(const User *U) const {
410    if (isa<PHINode>(U))
411      return TCC_Free; // Model all PHI nodes as free.
412
413    if (const GEPOperator *GEP = dyn_cast<GEPOperator>(U))
414      // In the basic model we just assume that all-constant GEPs will be
415      // folded into their uses via addressing modes.
416      return GEP->hasAllConstantIndices() ? TCC_Free : TCC_Basic;
417
418    if (ImmutableCallSite CS = U) {
419      const Function *F = CS.getCalledFunction();
420      if (!F) {
421        // Just use the called value type.
422        Type *FTy = CS.getCalledValue()->getType()->getPointerElementType();
423        return TopTTI->getCallCost(cast<FunctionType>(FTy), CS.arg_size());
424      }
425
426      SmallVector<const Value *, 8> Arguments;
427      for (ImmutableCallSite::arg_iterator AI = CS.arg_begin(),
428                                           AE = CS.arg_end();
429           AI != AE; ++AI)
430        Arguments.push_back(*AI);
431
432      return TopTTI->getCallCost(F, Arguments);
433    }
434
435    if (const CastInst *CI = dyn_cast<CastInst>(U)) {
436      // Result of a cmp instruction is often extended (to be used by other
437      // cmp instructions, logical or return instructions). These are usually
438      // nop on most sane targets.
439      if (isa<CmpInst>(CI->getOperand(0)))
440        return TCC_Free;
441    }
442
443    // Otherwise delegate to the fully generic implementations.
444    return getOperationCost(Operator::getOpcode(U), U->getType(),
445                            U->getNumOperands() == 1 ?
446                                U->getOperand(0)->getType() : 0);
447  }
448
449  bool hasBranchDivergence() const { return false; }
450
451  bool isLoweredToCall(const Function *F) const {
452    // FIXME: These should almost certainly not be handled here, and instead
453    // handled with the help of TLI or the target itself. This was largely
454    // ported from existing analysis heuristics here so that such refactorings
455    // can take place in the future.
456
457    if (F->isIntrinsic())
458      return false;
459
460    if (F->hasLocalLinkage() || !F->hasName())
461      return true;
462
463    StringRef Name = F->getName();
464
465    // These will all likely lower to a single selection DAG node.
466    if (Name == "copysign" || Name == "copysignf" || Name == "copysignl" ||
467        Name == "fabs" || Name == "fabsf" || Name == "fabsl" || Name == "sin" ||
468        Name == "sinf" || Name == "sinl" || Name == "cos" || Name == "cosf" ||
469        Name == "cosl" || Name == "sqrt" || Name == "sqrtf" || Name == "sqrtl")
470      return false;
471
472    // These are all likely to be optimized into something smaller.
473    if (Name == "pow" || Name == "powf" || Name == "powl" || Name == "exp2" ||
474        Name == "exp2l" || Name == "exp2f" || Name == "floor" || Name ==
475        "floorf" || Name == "ceil" || Name == "round" || Name == "ffs" ||
476        Name == "ffsl" || Name == "abs" || Name == "labs" || Name == "llabs")
477      return false;
478
479    return true;
480  }
481
482  void getUnrollingPreferences(Loop *, UnrollingPreferences &) const { }
483
484  bool isLegalAddImmediate(int64_t Imm) const {
485    return false;
486  }
487
488  bool isLegalICmpImmediate(int64_t Imm) const {
489    return false;
490  }
491
492  bool isLegalAddressingMode(Type *Ty, GlobalValue *BaseGV, int64_t BaseOffset,
493                             bool HasBaseReg, int64_t Scale) const {
494    // Guess that reg+reg addressing is allowed. This heuristic is taken from
495    // the implementation of LSR.
496    return !BaseGV && BaseOffset == 0 && Scale <= 1;
497  }
498
499  int getScalingFactorCost(Type *Ty, GlobalValue *BaseGV, int64_t BaseOffset,
500                           bool HasBaseReg, int64_t Scale) const {
501    // Guess that all legal addressing mode are free.
502    if(isLegalAddressingMode(Ty, BaseGV, BaseOffset, HasBaseReg, Scale))
503      return 0;
504    return -1;
505  }
506
507
508  bool isTruncateFree(Type *Ty1, Type *Ty2) const {
509    return false;
510  }
511
512  bool isTypeLegal(Type *Ty) const {
513    return false;
514  }
515
516  unsigned getJumpBufAlignment() const {
517    return 0;
518  }
519
520  unsigned getJumpBufSize() const {
521    return 0;
522  }
523
524  bool shouldBuildLookupTables() const {
525    return true;
526  }
527
528  PopcntSupportKind getPopcntSupport(unsigned IntTyWidthInBit) const {
529    return PSK_Software;
530  }
531
532  bool haveFastSqrt(Type *Ty) const {
533    return false;
534  }
535
536  unsigned getIntImmCost(const APInt &Imm, Type *Ty) const {
537    return 1;
538  }
539
540  unsigned getNumberOfRegisters(bool Vector) const {
541    return 8;
542  }
543
544  unsigned  getRegisterBitWidth(bool Vector) const {
545    return 32;
546  }
547
548  unsigned getMaximumUnrollFactor() const {
549    return 1;
550  }
551
552  unsigned getArithmeticInstrCost(unsigned Opcode, Type *Ty, OperandValueKind,
553                                  OperandValueKind) const {
554    return 1;
555  }
556
557  unsigned getShuffleCost(ShuffleKind Kind, Type *Tp,
558                          int Index = 0, Type *SubTp = 0) const {
559    return 1;
560  }
561
562  unsigned getCastInstrCost(unsigned Opcode, Type *Dst,
563                            Type *Src) const {
564    return 1;
565  }
566
567  unsigned getCFInstrCost(unsigned Opcode) const {
568    return 1;
569  }
570
571  unsigned getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
572                              Type *CondTy = 0) const {
573    return 1;
574  }
575
576  unsigned getVectorInstrCost(unsigned Opcode, Type *Val,
577                              unsigned Index = -1) const {
578    return 1;
579  }
580
581  unsigned getMemoryOpCost(unsigned Opcode, Type *Src,
582                           unsigned Alignment,
583                           unsigned AddressSpace) const {
584    return 1;
585  }
586
587  unsigned getIntrinsicInstrCost(Intrinsic::ID ID,
588                                 Type *RetTy,
589                                 ArrayRef<Type*> Tys) const {
590    return 1;
591  }
592
593  unsigned getNumberOfParts(Type *Tp) const {
594    return 0;
595  }
596
597  unsigned getAddressComputationCost(Type *Tp, bool) const {
598    return 0;
599  }
600
601  unsigned getReductionCost(unsigned, Type *, bool) const {
602    return 1;
603  }
604};
605
606} // end anonymous namespace
607
608INITIALIZE_AG_PASS(NoTTI, TargetTransformInfo, "notti",
609                   "No target information", true, true, true)
610char NoTTI::ID = 0;
611
612ImmutablePass *llvm::createNoTargetTransformInfoPass() {
613  return new NoTTI();
614}
615