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::isLoweredToCall(const Function *F) const {
92  return PrevTTI->isLoweredToCall(F);
93}
94
95bool TargetTransformInfo::isLegalAddImmediate(int64_t Imm) const {
96  return PrevTTI->isLegalAddImmediate(Imm);
97}
98
99bool TargetTransformInfo::isLegalICmpImmediate(int64_t Imm) const {
100  return PrevTTI->isLegalICmpImmediate(Imm);
101}
102
103bool 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
111bool TargetTransformInfo::isTruncateFree(Type *Ty1, Type *Ty2) const {
112  return PrevTTI->isTruncateFree(Ty1, Ty2);
113}
114
115bool TargetTransformInfo::isTypeLegal(Type *Ty) const {
116  return PrevTTI->isTypeLegal(Ty);
117}
118
119unsigned TargetTransformInfo::getJumpBufAlignment() const {
120  return PrevTTI->getJumpBufAlignment();
121}
122
123unsigned TargetTransformInfo::getJumpBufSize() const {
124  return PrevTTI->getJumpBufSize();
125}
126
127bool TargetTransformInfo::shouldBuildLookupTables() const {
128  return PrevTTI->shouldBuildLookupTables();
129}
130
131TargetTransformInfo::PopcntSupportKind
132TargetTransformInfo::getPopcntSupport(unsigned IntTyWidthInBit) const {
133  return PrevTTI->getPopcntSupport(IntTyWidthInBit);
134}
135
136unsigned TargetTransformInfo::getIntImmCost(const APInt &Imm, Type *Ty) const {
137  return PrevTTI->getIntImmCost(Imm, Ty);
138}
139
140unsigned TargetTransformInfo::getNumberOfRegisters(bool Vector) const {
141  return PrevTTI->getNumberOfRegisters(Vector);
142}
143
144unsigned TargetTransformInfo::getRegisterBitWidth(bool Vector) const {
145  return PrevTTI->getRegisterBitWidth(Vector);
146}
147
148unsigned TargetTransformInfo::getMaximumUnrollFactor() const {
149  return PrevTTI->getMaximumUnrollFactor();
150}
151
152unsigned TargetTransformInfo::getArithmeticInstrCost(unsigned Opcode,
153                                                     Type *Ty) const {
154  return PrevTTI->getArithmeticInstrCost(Opcode, Ty);
155}
156
157unsigned TargetTransformInfo::getShuffleCost(ShuffleKind Kind, Type *Tp,
158                                             int Index, Type *SubTp) const {
159  return PrevTTI->getShuffleCost(Kind, Tp, Index, SubTp);
160}
161
162unsigned TargetTransformInfo::getCastInstrCost(unsigned Opcode, Type *Dst,
163                                               Type *Src) const {
164  return PrevTTI->getCastInstrCost(Opcode, Dst, Src);
165}
166
167unsigned TargetTransformInfo::getCFInstrCost(unsigned Opcode) const {
168  return PrevTTI->getCFInstrCost(Opcode);
169}
170
171unsigned TargetTransformInfo::getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
172                                                 Type *CondTy) const {
173  return PrevTTI->getCmpSelInstrCost(Opcode, ValTy, CondTy);
174}
175
176unsigned TargetTransformInfo::getVectorInstrCost(unsigned Opcode, Type *Val,
177                                                 unsigned Index) const {
178  return PrevTTI->getVectorInstrCost(Opcode, Val, Index);
179}
180
181unsigned TargetTransformInfo::getMemoryOpCost(unsigned Opcode, Type *Src,
182                                              unsigned Alignment,
183                                              unsigned AddressSpace) const {
184  return PrevTTI->getMemoryOpCost(Opcode, Src, Alignment, AddressSpace);
185  ;
186}
187
188unsigned
189TargetTransformInfo::getIntrinsicInstrCost(Intrinsic::ID ID,
190                                           Type *RetTy,
191                                           ArrayRef<Type *> Tys) const {
192  return PrevTTI->getIntrinsicInstrCost(ID, RetTy, Tys);
193}
194
195unsigned TargetTransformInfo::getNumberOfParts(Type *Tp) const {
196  return PrevTTI->getNumberOfParts(Tp);
197}
198
199unsigned TargetTransformInfo::getAddressComputationCost(Type *Tp) const {
200  return PrevTTI->getAddressComputationCost(Tp);
201}
202
203namespace {
204
205struct 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
549INITIALIZE_AG_PASS(NoTTI, TargetTransformInfo, "notti",
550                   "No target information", true, true, true)
551char NoTTI::ID = 0;
552
553ImmutablePass *llvm::createNoTargetTransformInfoPass() {
554  return new NoTTI();
555}
556