InstCombineCalls.cpp revision dce4a407a24b04eebc6a376f8e62b41aaa7b071f 
1//===- InstCombineCalls.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// This file implements the visitCall and visitInvoke functions.
11//
12//===----------------------------------------------------------------------===//
13
14#include "InstCombine.h"
15#include "llvm/ADT/Statistic.h"
16#include "llvm/Analysis/MemoryBuiltins.h"
17#include "llvm/IR/CallSite.h"
18#include "llvm/IR/DataLayout.h"
19#include "llvm/IR/PatternMatch.h"
20#include "llvm/Transforms/Utils/BuildLibCalls.h"
21#include "llvm/Transforms/Utils/Local.h"
22using namespace llvm;
23using namespace PatternMatch;
24
25#define DEBUG_TYPE "instcombine"
26
27STATISTIC(NumSimplified, "Number of library calls simplified");
28
29/// getPromotedType - Return the specified type promoted as it would be to pass
30/// though a va_arg area.
31static Type *getPromotedType(Type *Ty) {
32  if (IntegerType* ITy = dyn_cast<IntegerType>(Ty)) {
33    if (ITy->getBitWidth() < 32)
34      return Type::getInt32Ty(Ty->getContext());
35  }
36  return Ty;
37}
38
39/// reduceToSingleValueType - Given an aggregate type which ultimately holds a
40/// single scalar element, like {{{type}}} or [1 x type], return type.
41static Type *reduceToSingleValueType(Type *T) {
42  while (!T->isSingleValueType()) {
43    if (StructType *STy = dyn_cast<StructType>(T)) {
44      if (STy->getNumElements() == 1)
45        T = STy->getElementType(0);
46      else
47        break;
48    } else if (ArrayType *ATy = dyn_cast<ArrayType>(T)) {
49      if (ATy->getNumElements() == 1)
50        T = ATy->getElementType();
51      else
52        break;
53    } else
54      break;
55  }
56
57  return T;
58}
59
60Instruction *InstCombiner::SimplifyMemTransfer(MemIntrinsic *MI) {
61  unsigned DstAlign = getKnownAlignment(MI->getArgOperand(0), DL);
62  unsigned SrcAlign = getKnownAlignment(MI->getArgOperand(1), DL);
63  unsigned MinAlign = std::min(DstAlign, SrcAlign);
64  unsigned CopyAlign = MI->getAlignment();
65
66  if (CopyAlign < MinAlign) {
67    MI->setAlignment(ConstantInt::get(MI->getAlignmentType(),
68                                             MinAlign, false));
69    return MI;
70  }
71
72  // If MemCpyInst length is 1/2/4/8 bytes then replace memcpy with
73  // load/store.
74  ConstantInt *MemOpLength = dyn_cast<ConstantInt>(MI->getArgOperand(2));
75  if (!MemOpLength) return nullptr;
76
77  // Source and destination pointer types are always "i8*" for intrinsic.  See
78  // if the size is something we can handle with a single primitive load/store.
79  // A single load+store correctly handles overlapping memory in the memmove
80  // case.
81  uint64_t Size = MemOpLength->getLimitedValue();
82  assert(Size && "0-sized memory transferring should be removed already.");
83
84  if (Size > 8 || (Size&(Size-1)))
85    return nullptr;  // If not 1/2/4/8 bytes, exit.
86
87  // Use an integer load+store unless we can find something better.
88  unsigned SrcAddrSp =
89    cast<PointerType>(MI->getArgOperand(1)->getType())->getAddressSpace();
90  unsigned DstAddrSp =
91    cast<PointerType>(MI->getArgOperand(0)->getType())->getAddressSpace();
92
93  IntegerType* IntType = IntegerType::get(MI->getContext(), Size<<3);
94  Type *NewSrcPtrTy = PointerType::get(IntType, SrcAddrSp);
95  Type *NewDstPtrTy = PointerType::get(IntType, DstAddrSp);
96
97  // Memcpy forces the use of i8* for the source and destination.  That means
98  // that if you're using memcpy to move one double around, you'll get a cast
99  // from double* to i8*.  We'd much rather use a double load+store rather than
100  // an i64 load+store, here because this improves the odds that the source or
101  // dest address will be promotable.  See if we can find a better type than the
102  // integer datatype.
103  Value *StrippedDest = MI->getArgOperand(0)->stripPointerCasts();
104  MDNode *CopyMD = nullptr;
105  if (StrippedDest != MI->getArgOperand(0)) {
106    Type *SrcETy = cast<PointerType>(StrippedDest->getType())
107                                    ->getElementType();
108    if (DL && SrcETy->isSized() && DL->getTypeStoreSize(SrcETy) == Size) {
109      // The SrcETy might be something like {{{double}}} or [1 x double].  Rip
110      // down through these levels if so.
111      SrcETy = reduceToSingleValueType(SrcETy);
112
113      if (SrcETy->isSingleValueType()) {
114        NewSrcPtrTy = PointerType::get(SrcETy, SrcAddrSp);
115        NewDstPtrTy = PointerType::get(SrcETy, DstAddrSp);
116
117        // If the memcpy has metadata describing the members, see if we can
118        // get the TBAA tag describing our copy.
119        if (MDNode *M = MI->getMetadata(LLVMContext::MD_tbaa_struct)) {
120          if (M->getNumOperands() == 3 &&
121              M->getOperand(0) &&
122              isa<ConstantInt>(M->getOperand(0)) &&
123              cast<ConstantInt>(M->getOperand(0))->isNullValue() &&
124              M->getOperand(1) &&
125              isa<ConstantInt>(M->getOperand(1)) &&
126              cast<ConstantInt>(M->getOperand(1))->getValue() == Size &&
127              M->getOperand(2) &&
128              isa<MDNode>(M->getOperand(2)))
129            CopyMD = cast<MDNode>(M->getOperand(2));
130        }
131      }
132    }
133  }
134
135  // If the memcpy/memmove provides better alignment info than we can
136  // infer, use it.
137  SrcAlign = std::max(SrcAlign, CopyAlign);
138  DstAlign = std::max(DstAlign, CopyAlign);
139
140  Value *Src = Builder->CreateBitCast(MI->getArgOperand(1), NewSrcPtrTy);
141  Value *Dest = Builder->CreateBitCast(MI->getArgOperand(0), NewDstPtrTy);
142  LoadInst *L = Builder->CreateLoad(Src, MI->isVolatile());
143  L->setAlignment(SrcAlign);
144  if (CopyMD)
145    L->setMetadata(LLVMContext::MD_tbaa, CopyMD);
146  StoreInst *S = Builder->CreateStore(L, Dest, MI->isVolatile());
147  S->setAlignment(DstAlign);
148  if (CopyMD)
149    S->setMetadata(LLVMContext::MD_tbaa, CopyMD);
150
151  // Set the size of the copy to 0, it will be deleted on the next iteration.
152  MI->setArgOperand(2, Constant::getNullValue(MemOpLength->getType()));
153  return MI;
154}
155
156Instruction *InstCombiner::SimplifyMemSet(MemSetInst *MI) {
157  unsigned Alignment = getKnownAlignment(MI->getDest(), DL);
158  if (MI->getAlignment() < Alignment) {
159    MI->setAlignment(ConstantInt::get(MI->getAlignmentType(),
160                                             Alignment, false));
161    return MI;
162  }
163
164  // Extract the length and alignment and fill if they are constant.
165  ConstantInt *LenC = dyn_cast<ConstantInt>(MI->getLength());
166  ConstantInt *FillC = dyn_cast<ConstantInt>(MI->getValue());
167  if (!LenC || !FillC || !FillC->getType()->isIntegerTy(8))
168    return nullptr;
169  uint64_t Len = LenC->getLimitedValue();
170  Alignment = MI->getAlignment();
171  assert(Len && "0-sized memory setting should be removed already.");
172
173  // memset(s,c,n) -> store s, c (for n=1,2,4,8)
174  if (Len <= 8 && isPowerOf2_32((uint32_t)Len)) {
175    Type *ITy = IntegerType::get(MI->getContext(), Len*8);  // n=1 -> i8.
176
177    Value *Dest = MI->getDest();
178    unsigned DstAddrSp = cast<PointerType>(Dest->getType())->getAddressSpace();
179    Type *NewDstPtrTy = PointerType::get(ITy, DstAddrSp);
180    Dest = Builder->CreateBitCast(Dest, NewDstPtrTy);
181
182    // Alignment 0 is identity for alignment 1 for memset, but not store.
183    if (Alignment == 0) Alignment = 1;
184
185    // Extract the fill value and store.
186    uint64_t Fill = FillC->getZExtValue()*0x0101010101010101ULL;
187    StoreInst *S = Builder->CreateStore(ConstantInt::get(ITy, Fill), Dest,
188                                        MI->isVolatile());
189    S->setAlignment(Alignment);
190
191    // Set the size of the copy to 0, it will be deleted on the next iteration.
192    MI->setLength(Constant::getNullValue(LenC->getType()));
193    return MI;
194  }
195
196  return nullptr;
197}
198
199/// visitCallInst - CallInst simplification.  This mostly only handles folding
200/// of intrinsic instructions.  For normal calls, it allows visitCallSite to do
201/// the heavy lifting.
202///
203Instruction *InstCombiner::visitCallInst(CallInst &CI) {
204  if (isFreeCall(&CI, TLI))
205    return visitFree(CI);
206
207  // If the caller function is nounwind, mark the call as nounwind, even if the
208  // callee isn't.
209  if (CI.getParent()->getParent()->doesNotThrow() &&
210      !CI.doesNotThrow()) {
211    CI.setDoesNotThrow();
212    return &CI;
213  }
214
215  IntrinsicInst *II = dyn_cast<IntrinsicInst>(&CI);
216  if (!II) return visitCallSite(&CI);
217
218  // Intrinsics cannot occur in an invoke, so handle them here instead of in
219  // visitCallSite.
220  if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(II)) {
221    bool Changed = false;
222
223    // memmove/cpy/set of zero bytes is a noop.
224    if (Constant *NumBytes = dyn_cast<Constant>(MI->getLength())) {
225      if (NumBytes->isNullValue())
226        return EraseInstFromFunction(CI);
227
228      if (ConstantInt *CI = dyn_cast<ConstantInt>(NumBytes))
229        if (CI->getZExtValue() == 1) {
230          // Replace the instruction with just byte operations.  We would
231          // transform other cases to loads/stores, but we don't know if
232          // alignment is sufficient.
233        }
234    }
235
236    // No other transformations apply to volatile transfers.
237    if (MI->isVolatile())
238      return nullptr;
239
240    // If we have a memmove and the source operation is a constant global,
241    // then the source and dest pointers can't alias, so we can change this
242    // into a call to memcpy.
243    if (MemMoveInst *MMI = dyn_cast<MemMoveInst>(MI)) {
244      if (GlobalVariable *GVSrc = dyn_cast<GlobalVariable>(MMI->getSource()))
245        if (GVSrc->isConstant()) {
246          Module *M = CI.getParent()->getParent()->getParent();
247          Intrinsic::ID MemCpyID = Intrinsic::memcpy;
248          Type *Tys[3] = { CI.getArgOperand(0)->getType(),
249                           CI.getArgOperand(1)->getType(),
250                           CI.getArgOperand(2)->getType() };
251          CI.setCalledFunction(Intrinsic::getDeclaration(M, MemCpyID, Tys));
252          Changed = true;
253        }
254    }
255
256    if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) {
257      // memmove(x,x,size) -> noop.
258      if (MTI->getSource() == MTI->getDest())
259        return EraseInstFromFunction(CI);
260    }
261
262    // If we can determine a pointer alignment that is bigger than currently
263    // set, update the alignment.
264    if (isa<MemTransferInst>(MI)) {
265      if (Instruction *I = SimplifyMemTransfer(MI))
266        return I;
267    } else if (MemSetInst *MSI = dyn_cast<MemSetInst>(MI)) {
268      if (Instruction *I = SimplifyMemSet(MSI))
269        return I;
270    }
271
272    if (Changed) return II;
273  }
274
275  switch (II->getIntrinsicID()) {
276  default: break;
277  case Intrinsic::objectsize: {
278    uint64_t Size;
279    if (getObjectSize(II->getArgOperand(0), Size, DL, TLI))
280      return ReplaceInstUsesWith(CI, ConstantInt::get(CI.getType(), Size));
281    return nullptr;
282  }
283  case Intrinsic::bswap: {
284    Value *IIOperand = II->getArgOperand(0);
285    Value *X = nullptr;
286
287    // bswap(bswap(x)) -> x
288    if (match(IIOperand, m_BSwap(m_Value(X))))
289        return ReplaceInstUsesWith(CI, X);
290
291    // bswap(trunc(bswap(x))) -> trunc(lshr(x, c))
292    if (match(IIOperand, m_Trunc(m_BSwap(m_Value(X))))) {
293      unsigned C = X->getType()->getPrimitiveSizeInBits() -
294        IIOperand->getType()->getPrimitiveSizeInBits();
295      Value *CV = ConstantInt::get(X->getType(), C);
296      Value *V = Builder->CreateLShr(X, CV);
297      return new TruncInst(V, IIOperand->getType());
298    }
299    break;
300  }
301
302  case Intrinsic::powi:
303    if (ConstantInt *Power = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
304      // powi(x, 0) -> 1.0
305      if (Power->isZero())
306        return ReplaceInstUsesWith(CI, ConstantFP::get(CI.getType(), 1.0));
307      // powi(x, 1) -> x
308      if (Power->isOne())
309        return ReplaceInstUsesWith(CI, II->getArgOperand(0));
310      // powi(x, -1) -> 1/x
311      if (Power->isAllOnesValue())
312        return BinaryOperator::CreateFDiv(ConstantFP::get(CI.getType(), 1.0),
313                                          II->getArgOperand(0));
314    }
315    break;
316  case Intrinsic::cttz: {
317    // If all bits below the first known one are known zero,
318    // this value is constant.
319    IntegerType *IT = dyn_cast<IntegerType>(II->getArgOperand(0)->getType());
320    // FIXME: Try to simplify vectors of integers.
321    if (!IT) break;
322    uint32_t BitWidth = IT->getBitWidth();
323    APInt KnownZero(BitWidth, 0);
324    APInt KnownOne(BitWidth, 0);
325    computeKnownBits(II->getArgOperand(0), KnownZero, KnownOne);
326    unsigned TrailingZeros = KnownOne.countTrailingZeros();
327    APInt Mask(APInt::getLowBitsSet(BitWidth, TrailingZeros));
328    if ((Mask & KnownZero) == Mask)
329      return ReplaceInstUsesWith(CI, ConstantInt::get(IT,
330                                 APInt(BitWidth, TrailingZeros)));
331
332    }
333    break;
334  case Intrinsic::ctlz: {
335    // If all bits above the first known one are known zero,
336    // this value is constant.
337    IntegerType *IT = dyn_cast<IntegerType>(II->getArgOperand(0)->getType());
338    // FIXME: Try to simplify vectors of integers.
339    if (!IT) break;
340    uint32_t BitWidth = IT->getBitWidth();
341    APInt KnownZero(BitWidth, 0);
342    APInt KnownOne(BitWidth, 0);
343    computeKnownBits(II->getArgOperand(0), KnownZero, KnownOne);
344    unsigned LeadingZeros = KnownOne.countLeadingZeros();
345    APInt Mask(APInt::getHighBitsSet(BitWidth, LeadingZeros));
346    if ((Mask & KnownZero) == Mask)
347      return ReplaceInstUsesWith(CI, ConstantInt::get(IT,
348                                 APInt(BitWidth, LeadingZeros)));
349
350    }
351    break;
352  case Intrinsic::uadd_with_overflow: {
353    Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1);
354    IntegerType *IT = cast<IntegerType>(II->getArgOperand(0)->getType());
355    uint32_t BitWidth = IT->getBitWidth();
356    APInt LHSKnownZero(BitWidth, 0);
357    APInt LHSKnownOne(BitWidth, 0);
358    computeKnownBits(LHS, LHSKnownZero, LHSKnownOne);
359    bool LHSKnownNegative = LHSKnownOne[BitWidth - 1];
360    bool LHSKnownPositive = LHSKnownZero[BitWidth - 1];
361
362    if (LHSKnownNegative || LHSKnownPositive) {
363      APInt RHSKnownZero(BitWidth, 0);
364      APInt RHSKnownOne(BitWidth, 0);
365      computeKnownBits(RHS, RHSKnownZero, RHSKnownOne);
366      bool RHSKnownNegative = RHSKnownOne[BitWidth - 1];
367      bool RHSKnownPositive = RHSKnownZero[BitWidth - 1];
368      if (LHSKnownNegative && RHSKnownNegative) {
369        // The sign bit is set in both cases: this MUST overflow.
370        // Create a simple add instruction, and insert it into the struct.
371        Value *Add = Builder->CreateAdd(LHS, RHS);
372        Add->takeName(&CI);
373        Constant *V[] = {
374          UndefValue::get(LHS->getType()),
375          ConstantInt::getTrue(II->getContext())
376        };
377        StructType *ST = cast<StructType>(II->getType());
378        Constant *Struct = ConstantStruct::get(ST, V);
379        return InsertValueInst::Create(Struct, Add, 0);
380      }
381
382      if (LHSKnownPositive && RHSKnownPositive) {
383        // The sign bit is clear in both cases: this CANNOT overflow.
384        // Create a simple add instruction, and insert it into the struct.
385        Value *Add = Builder->CreateNUWAdd(LHS, RHS);
386        Add->takeName(&CI);
387        Constant *V[] = {
388          UndefValue::get(LHS->getType()),
389          ConstantInt::getFalse(II->getContext())
390        };
391        StructType *ST = cast<StructType>(II->getType());
392        Constant *Struct = ConstantStruct::get(ST, V);
393        return InsertValueInst::Create(Struct, Add, 0);
394      }
395    }
396  }
397  // FALL THROUGH uadd into sadd
398  case Intrinsic::sadd_with_overflow:
399    // Canonicalize constants into the RHS.
400    if (isa<Constant>(II->getArgOperand(0)) &&
401        !isa<Constant>(II->getArgOperand(1))) {
402      Value *LHS = II->getArgOperand(0);
403      II->setArgOperand(0, II->getArgOperand(1));
404      II->setArgOperand(1, LHS);
405      return II;
406    }
407
408    // X + undef -> undef
409    if (isa<UndefValue>(II->getArgOperand(1)))
410      return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
411
412    if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
413      // X + 0 -> {X, false}
414      if (RHS->isZero()) {
415        Constant *V[] = {
416          UndefValue::get(II->getArgOperand(0)->getType()),
417          ConstantInt::getFalse(II->getContext())
418        };
419        Constant *Struct =
420          ConstantStruct::get(cast<StructType>(II->getType()), V);
421        return InsertValueInst::Create(Struct, II->getArgOperand(0), 0);
422      }
423    }
424    break;
425  case Intrinsic::usub_with_overflow:
426  case Intrinsic::ssub_with_overflow:
427    // undef - X -> undef
428    // X - undef -> undef
429    if (isa<UndefValue>(II->getArgOperand(0)) ||
430        isa<UndefValue>(II->getArgOperand(1)))
431      return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
432
433    if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
434      // X - 0 -> {X, false}
435      if (RHS->isZero()) {
436        Constant *V[] = {
437          UndefValue::get(II->getArgOperand(0)->getType()),
438          ConstantInt::getFalse(II->getContext())
439        };
440        Constant *Struct =
441          ConstantStruct::get(cast<StructType>(II->getType()), V);
442        return InsertValueInst::Create(Struct, II->getArgOperand(0), 0);
443      }
444    }
445    break;
446  case Intrinsic::umul_with_overflow: {
447    Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1);
448    unsigned BitWidth = cast<IntegerType>(LHS->getType())->getBitWidth();
449
450    APInt LHSKnownZero(BitWidth, 0);
451    APInt LHSKnownOne(BitWidth, 0);
452    computeKnownBits(LHS, LHSKnownZero, LHSKnownOne);
453    APInt RHSKnownZero(BitWidth, 0);
454    APInt RHSKnownOne(BitWidth, 0);
455    computeKnownBits(RHS, RHSKnownZero, RHSKnownOne);
456
457    // Get the largest possible values for each operand.
458    APInt LHSMax = ~LHSKnownZero;
459    APInt RHSMax = ~RHSKnownZero;
460
461    // If multiplying the maximum values does not overflow then we can turn
462    // this into a plain NUW mul.
463    bool Overflow;
464    LHSMax.umul_ov(RHSMax, Overflow);
465    if (!Overflow) {
466      Value *Mul = Builder->CreateNUWMul(LHS, RHS, "umul_with_overflow");
467      Constant *V[] = {
468        UndefValue::get(LHS->getType()),
469        Builder->getFalse()
470      };
471      Constant *Struct = ConstantStruct::get(cast<StructType>(II->getType()),V);
472      return InsertValueInst::Create(Struct, Mul, 0);
473    }
474  } // FALL THROUGH
475  case Intrinsic::smul_with_overflow:
476    // Canonicalize constants into the RHS.
477    if (isa<Constant>(II->getArgOperand(0)) &&
478        !isa<Constant>(II->getArgOperand(1))) {
479      Value *LHS = II->getArgOperand(0);
480      II->setArgOperand(0, II->getArgOperand(1));
481      II->setArgOperand(1, LHS);
482      return II;
483    }
484
485    // X * undef -> undef
486    if (isa<UndefValue>(II->getArgOperand(1)))
487      return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
488
489    if (ConstantInt *RHSI = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
490      // X*0 -> {0, false}
491      if (RHSI->isZero())
492        return ReplaceInstUsesWith(CI, Constant::getNullValue(II->getType()));
493
494      // X * 1 -> {X, false}
495      if (RHSI->equalsInt(1)) {
496        Constant *V[] = {
497          UndefValue::get(II->getArgOperand(0)->getType()),
498          ConstantInt::getFalse(II->getContext())
499        };
500        Constant *Struct =
501          ConstantStruct::get(cast<StructType>(II->getType()), V);
502        return InsertValueInst::Create(Struct, II->getArgOperand(0), 0);
503      }
504    }
505    break;
506  case Intrinsic::ppc_altivec_lvx:
507  case Intrinsic::ppc_altivec_lvxl:
508    // Turn PPC lvx -> load if the pointer is known aligned.
509    if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, DL) >= 16) {
510      Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0),
511                                         PointerType::getUnqual(II->getType()));
512      return new LoadInst(Ptr);
513    }
514    break;
515  case Intrinsic::ppc_altivec_stvx:
516  case Intrinsic::ppc_altivec_stvxl:
517    // Turn stvx -> store if the pointer is known aligned.
518    if (getOrEnforceKnownAlignment(II->getArgOperand(1), 16, DL) >= 16) {
519      Type *OpPtrTy =
520        PointerType::getUnqual(II->getArgOperand(0)->getType());
521      Value *Ptr = Builder->CreateBitCast(II->getArgOperand(1), OpPtrTy);
522      return new StoreInst(II->getArgOperand(0), Ptr);
523    }
524    break;
525  case Intrinsic::x86_sse_storeu_ps:
526  case Intrinsic::x86_sse2_storeu_pd:
527  case Intrinsic::x86_sse2_storeu_dq:
528    // Turn X86 storeu -> store if the pointer is known aligned.
529    if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, DL) >= 16) {
530      Type *OpPtrTy =
531        PointerType::getUnqual(II->getArgOperand(1)->getType());
532      Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), OpPtrTy);
533      return new StoreInst(II->getArgOperand(1), Ptr);
534    }
535    break;
536
537  case Intrinsic::x86_sse_cvtss2si:
538  case Intrinsic::x86_sse_cvtss2si64:
539  case Intrinsic::x86_sse_cvttss2si:
540  case Intrinsic::x86_sse_cvttss2si64:
541  case Intrinsic::x86_sse2_cvtsd2si:
542  case Intrinsic::x86_sse2_cvtsd2si64:
543  case Intrinsic::x86_sse2_cvttsd2si:
544  case Intrinsic::x86_sse2_cvttsd2si64: {
545    // These intrinsics only demand the 0th element of their input vectors. If
546    // we can simplify the input based on that, do so now.
547    unsigned VWidth =
548      cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements();
549    APInt DemandedElts(VWidth, 1);
550    APInt UndefElts(VWidth, 0);
551    if (Value *V = SimplifyDemandedVectorElts(II->getArgOperand(0),
552                                              DemandedElts, UndefElts)) {
553      II->setArgOperand(0, V);
554      return II;
555    }
556    break;
557  }
558
559  // Constant fold <A x Bi> << Ci.
560  // FIXME: We don't handle _dq because it's a shift of an i128, but is
561  // represented in the IR as <2 x i64>. A per element shift is wrong.
562  case Intrinsic::x86_sse2_psll_d:
563  case Intrinsic::x86_sse2_psll_q:
564  case Intrinsic::x86_sse2_psll_w:
565  case Intrinsic::x86_sse2_pslli_d:
566  case Intrinsic::x86_sse2_pslli_q:
567  case Intrinsic::x86_sse2_pslli_w:
568  case Intrinsic::x86_avx2_psll_d:
569  case Intrinsic::x86_avx2_psll_q:
570  case Intrinsic::x86_avx2_psll_w:
571  case Intrinsic::x86_avx2_pslli_d:
572  case Intrinsic::x86_avx2_pslli_q:
573  case Intrinsic::x86_avx2_pslli_w:
574  case Intrinsic::x86_sse2_psrl_d:
575  case Intrinsic::x86_sse2_psrl_q:
576  case Intrinsic::x86_sse2_psrl_w:
577  case Intrinsic::x86_sse2_psrli_d:
578  case Intrinsic::x86_sse2_psrli_q:
579  case Intrinsic::x86_sse2_psrli_w:
580  case Intrinsic::x86_avx2_psrl_d:
581  case Intrinsic::x86_avx2_psrl_q:
582  case Intrinsic::x86_avx2_psrl_w:
583  case Intrinsic::x86_avx2_psrli_d:
584  case Intrinsic::x86_avx2_psrli_q:
585  case Intrinsic::x86_avx2_psrli_w: {
586    // Simplify if count is constant. To 0 if >= BitWidth,
587    // otherwise to shl/lshr.
588    auto CDV = dyn_cast<ConstantDataVector>(II->getArgOperand(1));
589    auto CInt = dyn_cast<ConstantInt>(II->getArgOperand(1));
590    if (!CDV && !CInt)
591      break;
592    ConstantInt *Count;
593    if (CDV)
594      Count = cast<ConstantInt>(CDV->getElementAsConstant(0));
595    else
596      Count = CInt;
597
598    auto Vec = II->getArgOperand(0);
599    auto VT = cast<VectorType>(Vec->getType());
600    if (Count->getZExtValue() >
601        VT->getElementType()->getPrimitiveSizeInBits() - 1)
602      return ReplaceInstUsesWith(
603          CI, ConstantAggregateZero::get(Vec->getType()));
604
605    bool isPackedShiftLeft = true;
606    switch (II->getIntrinsicID()) {
607    default : break;
608    case Intrinsic::x86_sse2_psrl_d:
609    case Intrinsic::x86_sse2_psrl_q:
610    case Intrinsic::x86_sse2_psrl_w:
611    case Intrinsic::x86_sse2_psrli_d:
612    case Intrinsic::x86_sse2_psrli_q:
613    case Intrinsic::x86_sse2_psrli_w:
614    case Intrinsic::x86_avx2_psrl_d:
615    case Intrinsic::x86_avx2_psrl_q:
616    case Intrinsic::x86_avx2_psrl_w:
617    case Intrinsic::x86_avx2_psrli_d:
618    case Intrinsic::x86_avx2_psrli_q:
619    case Intrinsic::x86_avx2_psrli_w: isPackedShiftLeft = false; break;
620    }
621
622    unsigned VWidth = VT->getNumElements();
623    // Get a constant vector of the same type as the first operand.
624    auto VTCI = ConstantInt::get(VT->getElementType(), Count->getZExtValue());
625    if (isPackedShiftLeft)
626      return BinaryOperator::CreateShl(Vec,
627          Builder->CreateVectorSplat(VWidth, VTCI));
628
629    return BinaryOperator::CreateLShr(Vec,
630        Builder->CreateVectorSplat(VWidth, VTCI));
631  }
632
633  case Intrinsic::x86_sse41_pmovsxbw:
634  case Intrinsic::x86_sse41_pmovsxwd:
635  case Intrinsic::x86_sse41_pmovsxdq:
636  case Intrinsic::x86_sse41_pmovzxbw:
637  case Intrinsic::x86_sse41_pmovzxwd:
638  case Intrinsic::x86_sse41_pmovzxdq: {
639    // pmov{s|z}x ignores the upper half of their input vectors.
640    unsigned VWidth =
641      cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements();
642    unsigned LowHalfElts = VWidth / 2;
643    APInt InputDemandedElts(APInt::getBitsSet(VWidth, 0, LowHalfElts));
644    APInt UndefElts(VWidth, 0);
645    if (Value *TmpV = SimplifyDemandedVectorElts(II->getArgOperand(0),
646                                                 InputDemandedElts,
647                                                 UndefElts)) {
648      II->setArgOperand(0, TmpV);
649      return II;
650    }
651    break;
652  }
653
654  case Intrinsic::x86_sse4a_insertqi: {
655    // insertqi x, y, 64, 0 can just copy y's lower bits and leave the top
656    // ones undef
657    // TODO: eventually we should lower this intrinsic to IR
658    if (auto CIWidth = dyn_cast<ConstantInt>(II->getArgOperand(2))) {
659      if (auto CIStart = dyn_cast<ConstantInt>(II->getArgOperand(3))) {
660        if (CIWidth->equalsInt(64) && CIStart->isZero()) {
661          Value *Vec = II->getArgOperand(1);
662          Value *Undef = UndefValue::get(Vec->getType());
663          const uint32_t Mask[] = { 0, 2 };
664          return ReplaceInstUsesWith(
665              CI,
666              Builder->CreateShuffleVector(
667                  Vec, Undef, ConstantDataVector::get(
668                                  II->getContext(), ArrayRef<uint32_t>(Mask))));
669
670        } else if (auto Source =
671                       dyn_cast<IntrinsicInst>(II->getArgOperand(0))) {
672          if (Source->hasOneUse() &&
673              Source->getArgOperand(1) == II->getArgOperand(1)) {
674            // If the source of the insert has only one use and it's another
675            // insert (and they're both inserting from the same vector), try to
676            // bundle both together.
677            auto CISourceWidth =
678                dyn_cast<ConstantInt>(Source->getArgOperand(2));
679            auto CISourceStart =
680                dyn_cast<ConstantInt>(Source->getArgOperand(3));
681            if (CISourceStart && CISourceWidth) {
682              unsigned Start = CIStart->getZExtValue();
683              unsigned Width = CIWidth->getZExtValue();
684              unsigned End = Start + Width;
685              unsigned SourceStart = CISourceStart->getZExtValue();
686              unsigned SourceWidth = CISourceWidth->getZExtValue();
687              unsigned SourceEnd = SourceStart + SourceWidth;
688              unsigned NewStart, NewWidth;
689              bool ShouldReplace = false;
690              if (Start <= SourceStart && SourceStart <= End) {
691                NewStart = Start;
692                NewWidth = std::max(End, SourceEnd) - NewStart;
693                ShouldReplace = true;
694              } else if (SourceStart <= Start && Start <= SourceEnd) {
695                NewStart = SourceStart;
696                NewWidth = std::max(SourceEnd, End) - NewStart;
697                ShouldReplace = true;
698              }
699
700              if (ShouldReplace) {
701                Constant *ConstantWidth = ConstantInt::get(
702                    II->getArgOperand(2)->getType(), NewWidth, false);
703                Constant *ConstantStart = ConstantInt::get(
704                    II->getArgOperand(3)->getType(), NewStart, false);
705                Value *Args[4] = { Source->getArgOperand(0),
706                                   II->getArgOperand(1), ConstantWidth,
707                                   ConstantStart };
708                Module *M = CI.getParent()->getParent()->getParent();
709                Value *F =
710                    Intrinsic::getDeclaration(M, Intrinsic::x86_sse4a_insertqi);
711                return ReplaceInstUsesWith(CI, Builder->CreateCall(F, Args));
712              }
713            }
714          }
715        }
716      }
717    }
718    break;
719  }
720
721  case Intrinsic::x86_sse41_pblendvb:
722  case Intrinsic::x86_sse41_blendvps:
723  case Intrinsic::x86_sse41_blendvpd:
724  case Intrinsic::x86_avx_blendv_ps_256:
725  case Intrinsic::x86_avx_blendv_pd_256:
726  case Intrinsic::x86_avx2_pblendvb: {
727    // Convert blendv* to vector selects if the mask is constant.
728    // This optimization is convoluted because the intrinsic is defined as
729    // getting a vector of floats or doubles for the ps and pd versions.
730    // FIXME: That should be changed.
731    Value *Mask = II->getArgOperand(2);
732    if (auto C = dyn_cast<ConstantDataVector>(Mask)) {
733      auto Tyi1 = Builder->getInt1Ty();
734      auto SelectorType = cast<VectorType>(Mask->getType());
735      auto EltTy = SelectorType->getElementType();
736      unsigned Size = SelectorType->getNumElements();
737      unsigned BitWidth =
738          EltTy->isFloatTy()
739              ? 32
740              : (EltTy->isDoubleTy() ? 64 : EltTy->getIntegerBitWidth());
741      assert((BitWidth == 64 || BitWidth == 32 || BitWidth == 8) &&
742             "Wrong arguments for variable blend intrinsic");
743      SmallVector<Constant *, 32> Selectors;
744      for (unsigned I = 0; I < Size; ++I) {
745        // The intrinsics only read the top bit
746        uint64_t Selector;
747        if (BitWidth == 8)
748          Selector = C->getElementAsInteger(I);
749        else
750          Selector = C->getElementAsAPFloat(I).bitcastToAPInt().getZExtValue();
751        Selectors.push_back(ConstantInt::get(Tyi1, Selector >> (BitWidth - 1)));
752      }
753      auto NewSelector = ConstantVector::get(Selectors);
754      return SelectInst::Create(NewSelector, II->getArgOperand(1),
755                                II->getArgOperand(0), "blendv");
756    } else {
757      break;
758    }
759  }
760
761  case Intrinsic::x86_avx_vpermilvar_ps:
762  case Intrinsic::x86_avx_vpermilvar_ps_256:
763  case Intrinsic::x86_avx_vpermilvar_pd:
764  case Intrinsic::x86_avx_vpermilvar_pd_256: {
765    // Convert vpermil* to shufflevector if the mask is constant.
766    Value *V = II->getArgOperand(1);
767    unsigned Size = cast<VectorType>(V->getType())->getNumElements();
768    assert(Size == 8 || Size == 4 || Size == 2);
769    uint32_t Indexes[8];
770    if (auto C = dyn_cast<ConstantDataVector>(V)) {
771      // The intrinsics only read one or two bits, clear the rest.
772      for (unsigned I = 0; I < Size; ++I) {
773        uint32_t Index = C->getElementAsInteger(I) & 0x3;
774        if (II->getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_pd ||
775            II->getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_pd_256)
776          Index >>= 1;
777        Indexes[I] = Index;
778      }
779    } else if (isa<ConstantAggregateZero>(V)) {
780      for (unsigned I = 0; I < Size; ++I)
781        Indexes[I] = 0;
782    } else {
783      break;
784    }
785    // The _256 variants are a bit trickier since the mask bits always index
786    // into the corresponding 128 half. In order to convert to a generic
787    // shuffle, we have to make that explicit.
788    if (II->getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_ps_256 ||
789        II->getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_pd_256) {
790      for (unsigned I = Size / 2; I < Size; ++I)
791        Indexes[I] += Size / 2;
792    }
793    auto NewC =
794        ConstantDataVector::get(V->getContext(), makeArrayRef(Indexes, Size));
795    auto V1 = II->getArgOperand(0);
796    auto V2 = UndefValue::get(V1->getType());
797    auto Shuffle = Builder->CreateShuffleVector(V1, V2, NewC);
798    return ReplaceInstUsesWith(CI, Shuffle);
799  }
800
801  case Intrinsic::ppc_altivec_vperm:
802    // Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant.
803    if (Constant *Mask = dyn_cast<Constant>(II->getArgOperand(2))) {
804      assert(Mask->getType()->getVectorNumElements() == 16 &&
805             "Bad type for intrinsic!");
806
807      // Check that all of the elements are integer constants or undefs.
808      bool AllEltsOk = true;
809      for (unsigned i = 0; i != 16; ++i) {
810        Constant *Elt = Mask->getAggregateElement(i);
811        if (!Elt || !(isa<ConstantInt>(Elt) || isa<UndefValue>(Elt))) {
812          AllEltsOk = false;
813          break;
814        }
815      }
816
817      if (AllEltsOk) {
818        // Cast the input vectors to byte vectors.
819        Value *Op0 = Builder->CreateBitCast(II->getArgOperand(0),
820                                            Mask->getType());
821        Value *Op1 = Builder->CreateBitCast(II->getArgOperand(1),
822                                            Mask->getType());
823        Value *Result = UndefValue::get(Op0->getType());
824
825        // Only extract each element once.
826        Value *ExtractedElts[32];
827        memset(ExtractedElts, 0, sizeof(ExtractedElts));
828
829        for (unsigned i = 0; i != 16; ++i) {
830          if (isa<UndefValue>(Mask->getAggregateElement(i)))
831            continue;
832          unsigned Idx =
833            cast<ConstantInt>(Mask->getAggregateElement(i))->getZExtValue();
834          Idx &= 31;  // Match the hardware behavior.
835
836          if (!ExtractedElts[Idx]) {
837            ExtractedElts[Idx] =
838              Builder->CreateExtractElement(Idx < 16 ? Op0 : Op1,
839                                            Builder->getInt32(Idx&15));
840          }
841
842          // Insert this value into the result vector.
843          Result = Builder->CreateInsertElement(Result, ExtractedElts[Idx],
844                                                Builder->getInt32(i));
845        }
846        return CastInst::Create(Instruction::BitCast, Result, CI.getType());
847      }
848    }
849    break;
850
851  case Intrinsic::arm_neon_vld1:
852  case Intrinsic::arm_neon_vld2:
853  case Intrinsic::arm_neon_vld3:
854  case Intrinsic::arm_neon_vld4:
855  case Intrinsic::arm_neon_vld2lane:
856  case Intrinsic::arm_neon_vld3lane:
857  case Intrinsic::arm_neon_vld4lane:
858  case Intrinsic::arm_neon_vst1:
859  case Intrinsic::arm_neon_vst2:
860  case Intrinsic::arm_neon_vst3:
861  case Intrinsic::arm_neon_vst4:
862  case Intrinsic::arm_neon_vst2lane:
863  case Intrinsic::arm_neon_vst3lane:
864  case Intrinsic::arm_neon_vst4lane: {
865    unsigned MemAlign = getKnownAlignment(II->getArgOperand(0), DL);
866    unsigned AlignArg = II->getNumArgOperands() - 1;
867    ConstantInt *IntrAlign = dyn_cast<ConstantInt>(II->getArgOperand(AlignArg));
868    if (IntrAlign && IntrAlign->getZExtValue() < MemAlign) {
869      II->setArgOperand(AlignArg,
870                        ConstantInt::get(Type::getInt32Ty(II->getContext()),
871                                         MemAlign, false));
872      return II;
873    }
874    break;
875  }
876
877  case Intrinsic::arm_neon_vmulls:
878  case Intrinsic::arm_neon_vmullu:
879  case Intrinsic::aarch64_neon_smull:
880  case Intrinsic::aarch64_neon_umull: {
881    Value *Arg0 = II->getArgOperand(0);
882    Value *Arg1 = II->getArgOperand(1);
883
884    // Handle mul by zero first:
885    if (isa<ConstantAggregateZero>(Arg0) || isa<ConstantAggregateZero>(Arg1)) {
886      return ReplaceInstUsesWith(CI, ConstantAggregateZero::get(II->getType()));
887    }
888
889    // Check for constant LHS & RHS - in this case we just simplify.
890    bool Zext = (II->getIntrinsicID() == Intrinsic::arm_neon_vmullu ||
891                 II->getIntrinsicID() == Intrinsic::aarch64_neon_umull);
892    VectorType *NewVT = cast<VectorType>(II->getType());
893    if (Constant *CV0 = dyn_cast<Constant>(Arg0)) {
894      if (Constant *CV1 = dyn_cast<Constant>(Arg1)) {
895        CV0 = ConstantExpr::getIntegerCast(CV0, NewVT, /*isSigned=*/!Zext);
896        CV1 = ConstantExpr::getIntegerCast(CV1, NewVT, /*isSigned=*/!Zext);
897
898        return ReplaceInstUsesWith(CI, ConstantExpr::getMul(CV0, CV1));
899      }
900
901      // Couldn't simplify - canonicalize constant to the RHS.
902      std::swap(Arg0, Arg1);
903    }
904
905    // Handle mul by one:
906    if (Constant *CV1 = dyn_cast<Constant>(Arg1))
907      if (ConstantInt *Splat =
908              dyn_cast_or_null<ConstantInt>(CV1->getSplatValue()))
909        if (Splat->isOne())
910          return CastInst::CreateIntegerCast(Arg0, II->getType(),
911                                             /*isSigned=*/!Zext);
912
913    break;
914  }
915
916  case Intrinsic::stackrestore: {
917    // If the save is right next to the restore, remove the restore.  This can
918    // happen when variable allocas are DCE'd.
919    if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) {
920      if (SS->getIntrinsicID() == Intrinsic::stacksave) {
921        BasicBlock::iterator BI = SS;
922        if (&*++BI == II)
923          return EraseInstFromFunction(CI);
924      }
925    }
926
927    // Scan down this block to see if there is another stack restore in the
928    // same block without an intervening call/alloca.
929    BasicBlock::iterator BI = II;
930    TerminatorInst *TI = II->getParent()->getTerminator();
931    bool CannotRemove = false;
932    for (++BI; &*BI != TI; ++BI) {
933      if (isa<AllocaInst>(BI)) {
934        CannotRemove = true;
935        break;
936      }
937      if (CallInst *BCI = dyn_cast<CallInst>(BI)) {
938        if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BCI)) {
939          // If there is a stackrestore below this one, remove this one.
940          if (II->getIntrinsicID() == Intrinsic::stackrestore)
941            return EraseInstFromFunction(CI);
942          // Otherwise, ignore the intrinsic.
943        } else {
944          // If we found a non-intrinsic call, we can't remove the stack
945          // restore.
946          CannotRemove = true;
947          break;
948        }
949      }
950    }
951
952    // If the stack restore is in a return, resume, or unwind block and if there
953    // are no allocas or calls between the restore and the return, nuke the
954    // restore.
955    if (!CannotRemove && (isa<ReturnInst>(TI) || isa<ResumeInst>(TI)))
956      return EraseInstFromFunction(CI);
957    break;
958  }
959  }
960
961  return visitCallSite(II);
962}
963
964// InvokeInst simplification
965//
966Instruction *InstCombiner::visitInvokeInst(InvokeInst &II) {
967  return visitCallSite(&II);
968}
969
970/// isSafeToEliminateVarargsCast - If this cast does not affect the value
971/// passed through the varargs area, we can eliminate the use of the cast.
972static bool isSafeToEliminateVarargsCast(const CallSite CS,
973                                         const CastInst * const CI,
974                                         const DataLayout * const DL,
975                                         const int ix) {
976  if (!CI->isLosslessCast())
977    return false;
978
979  // The size of ByVal or InAlloca arguments is derived from the type, so we
980  // can't change to a type with a different size.  If the size were
981  // passed explicitly we could avoid this check.
982  if (!CS.isByValOrInAllocaArgument(ix))
983    return true;
984
985  Type* SrcTy =
986            cast<PointerType>(CI->getOperand(0)->getType())->getElementType();
987  Type* DstTy = cast<PointerType>(CI->getType())->getElementType();
988  if (!SrcTy->isSized() || !DstTy->isSized())
989    return false;
990  if (!DL || DL->getTypeAllocSize(SrcTy) != DL->getTypeAllocSize(DstTy))
991    return false;
992  return true;
993}
994
995// Try to fold some different type of calls here.
996// Currently we're only working with the checking functions, memcpy_chk,
997// mempcpy_chk, memmove_chk, memset_chk, strcpy_chk, stpcpy_chk, strncpy_chk,
998// strcat_chk and strncat_chk.
999Instruction *InstCombiner::tryOptimizeCall(CallInst *CI, const DataLayout *DL) {
1000  if (!CI->getCalledFunction()) return nullptr;
1001
1002  if (Value *With = Simplifier->optimizeCall(CI)) {
1003    ++NumSimplified;
1004    return CI->use_empty() ? CI : ReplaceInstUsesWith(*CI, With);
1005  }
1006
1007  return nullptr;
1008}
1009
1010static IntrinsicInst *FindInitTrampolineFromAlloca(Value *TrampMem) {
1011  // Strip off at most one level of pointer casts, looking for an alloca.  This
1012  // is good enough in practice and simpler than handling any number of casts.
1013  Value *Underlying = TrampMem->stripPointerCasts();
1014  if (Underlying != TrampMem &&
1015      (!Underlying->hasOneUse() || Underlying->user_back() != TrampMem))
1016    return nullptr;
1017  if (!isa<AllocaInst>(Underlying))
1018    return nullptr;
1019
1020  IntrinsicInst *InitTrampoline = nullptr;
1021  for (User *U : TrampMem->users()) {
1022    IntrinsicInst *II = dyn_cast<IntrinsicInst>(U);
1023    if (!II)
1024      return nullptr;
1025    if (II->getIntrinsicID() == Intrinsic::init_trampoline) {
1026      if (InitTrampoline)
1027        // More than one init_trampoline writes to this value.  Give up.
1028        return nullptr;
1029      InitTrampoline = II;
1030      continue;
1031    }
1032    if (II->getIntrinsicID() == Intrinsic::adjust_trampoline)
1033      // Allow any number of calls to adjust.trampoline.
1034      continue;
1035    return nullptr;
1036  }
1037
1038  // No call to init.trampoline found.
1039  if (!InitTrampoline)
1040    return nullptr;
1041
1042  // Check that the alloca is being used in the expected way.
1043  if (InitTrampoline->getOperand(0) != TrampMem)
1044    return nullptr;
1045
1046  return InitTrampoline;
1047}
1048
1049static IntrinsicInst *FindInitTrampolineFromBB(IntrinsicInst *AdjustTramp,
1050                                               Value *TrampMem) {
1051  // Visit all the previous instructions in the basic block, and try to find a
1052  // init.trampoline which has a direct path to the adjust.trampoline.
1053  for (BasicBlock::iterator I = AdjustTramp,
1054       E = AdjustTramp->getParent()->begin(); I != E; ) {
1055    Instruction *Inst = --I;
1056    if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I))
1057      if (II->getIntrinsicID() == Intrinsic::init_trampoline &&
1058          II->getOperand(0) == TrampMem)
1059        return II;
1060    if (Inst->mayWriteToMemory())
1061      return nullptr;
1062  }
1063  return nullptr;
1064}
1065
1066// Given a call to llvm.adjust.trampoline, find and return the corresponding
1067// call to llvm.init.trampoline if the call to the trampoline can be optimized
1068// to a direct call to a function.  Otherwise return NULL.
1069//
1070static IntrinsicInst *FindInitTrampoline(Value *Callee) {
1071  Callee = Callee->stripPointerCasts();
1072  IntrinsicInst *AdjustTramp = dyn_cast<IntrinsicInst>(Callee);
1073  if (!AdjustTramp ||
1074      AdjustTramp->getIntrinsicID() != Intrinsic::adjust_trampoline)
1075    return nullptr;
1076
1077  Value *TrampMem = AdjustTramp->getOperand(0);
1078
1079  if (IntrinsicInst *IT = FindInitTrampolineFromAlloca(TrampMem))
1080    return IT;
1081  if (IntrinsicInst *IT = FindInitTrampolineFromBB(AdjustTramp, TrampMem))
1082    return IT;
1083  return nullptr;
1084}
1085
1086// visitCallSite - Improvements for call and invoke instructions.
1087//
1088Instruction *InstCombiner::visitCallSite(CallSite CS) {
1089  if (isAllocLikeFn(CS.getInstruction(), TLI))
1090    return visitAllocSite(*CS.getInstruction());
1091
1092  bool Changed = false;
1093
1094  // If the callee is a pointer to a function, attempt to move any casts to the
1095  // arguments of the call/invoke.
1096  Value *Callee = CS.getCalledValue();
1097  if (!isa<Function>(Callee) && transformConstExprCastCall(CS))
1098    return nullptr;
1099
1100  if (Function *CalleeF = dyn_cast<Function>(Callee))
1101    // If the call and callee calling conventions don't match, this call must
1102    // be unreachable, as the call is undefined.
1103    if (CalleeF->getCallingConv() != CS.getCallingConv() &&
1104        // Only do this for calls to a function with a body.  A prototype may
1105        // not actually end up matching the implementation's calling conv for a
1106        // variety of reasons (e.g. it may be written in assembly).
1107        !CalleeF->isDeclaration()) {
1108      Instruction *OldCall = CS.getInstruction();
1109      new StoreInst(ConstantInt::getTrue(Callee->getContext()),
1110                UndefValue::get(Type::getInt1PtrTy(Callee->getContext())),
1111                                  OldCall);
1112      // If OldCall does not return void then replaceAllUsesWith undef.
1113      // This allows ValueHandlers and custom metadata to adjust itself.
1114      if (!OldCall->getType()->isVoidTy())
1115        ReplaceInstUsesWith(*OldCall, UndefValue::get(OldCall->getType()));
1116      if (isa<CallInst>(OldCall))
1117        return EraseInstFromFunction(*OldCall);
1118
1119      // We cannot remove an invoke, because it would change the CFG, just
1120      // change the callee to a null pointer.
1121      cast<InvokeInst>(OldCall)->setCalledFunction(
1122                                    Constant::getNullValue(CalleeF->getType()));
1123      return nullptr;
1124    }
1125
1126  if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) {
1127    // If CS does not return void then replaceAllUsesWith undef.
1128    // This allows ValueHandlers and custom metadata to adjust itself.
1129    if (!CS.getInstruction()->getType()->isVoidTy())
1130      ReplaceInstUsesWith(*CS.getInstruction(),
1131                          UndefValue::get(CS.getInstruction()->getType()));
1132
1133    if (isa<InvokeInst>(CS.getInstruction())) {
1134      // Can't remove an invoke because we cannot change the CFG.
1135      return nullptr;
1136    }
1137
1138    // This instruction is not reachable, just remove it.  We insert a store to
1139    // undef so that we know that this code is not reachable, despite the fact
1140    // that we can't modify the CFG here.
1141    new StoreInst(ConstantInt::getTrue(Callee->getContext()),
1142                  UndefValue::get(Type::getInt1PtrTy(Callee->getContext())),
1143                  CS.getInstruction());
1144
1145    return EraseInstFromFunction(*CS.getInstruction());
1146  }
1147
1148  if (IntrinsicInst *II = FindInitTrampoline(Callee))
1149    return transformCallThroughTrampoline(CS, II);
1150
1151  PointerType *PTy = cast<PointerType>(Callee->getType());
1152  FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1153  if (FTy->isVarArg()) {
1154    int ix = FTy->getNumParams();
1155    // See if we can optimize any arguments passed through the varargs area of
1156    // the call.
1157    for (CallSite::arg_iterator I = CS.arg_begin() + FTy->getNumParams(),
1158           E = CS.arg_end(); I != E; ++I, ++ix) {
1159      CastInst *CI = dyn_cast<CastInst>(*I);
1160      if (CI && isSafeToEliminateVarargsCast(CS, CI, DL, ix)) {
1161        *I = CI->getOperand(0);
1162        Changed = true;
1163      }
1164    }
1165  }
1166
1167  if (isa<InlineAsm>(Callee) && !CS.doesNotThrow()) {
1168    // Inline asm calls cannot throw - mark them 'nounwind'.
1169    CS.setDoesNotThrow();
1170    Changed = true;
1171  }
1172
1173  // Try to optimize the call if possible, we require DataLayout for most of
1174  // this.  None of these calls are seen as possibly dead so go ahead and
1175  // delete the instruction now.
1176  if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction())) {
1177    Instruction *I = tryOptimizeCall(CI, DL);
1178    // If we changed something return the result, etc. Otherwise let
1179    // the fallthrough check.
1180    if (I) return EraseInstFromFunction(*I);
1181  }
1182
1183  return Changed ? CS.getInstruction() : nullptr;
1184}
1185
1186// transformConstExprCastCall - If the callee is a constexpr cast of a function,
1187// attempt to move the cast to the arguments of the call/invoke.
1188//
1189bool InstCombiner::transformConstExprCastCall(CallSite CS) {
1190  Function *Callee =
1191    dyn_cast<Function>(CS.getCalledValue()->stripPointerCasts());
1192  if (!Callee)
1193    return false;
1194  Instruction *Caller = CS.getInstruction();
1195  const AttributeSet &CallerPAL = CS.getAttributes();
1196
1197  // Okay, this is a cast from a function to a different type.  Unless doing so
1198  // would cause a type conversion of one of our arguments, change this call to
1199  // be a direct call with arguments casted to the appropriate types.
1200  //
1201  FunctionType *FT = Callee->getFunctionType();
1202  Type *OldRetTy = Caller->getType();
1203  Type *NewRetTy = FT->getReturnType();
1204
1205  // Check to see if we are changing the return type...
1206  if (OldRetTy != NewRetTy) {
1207
1208    if (NewRetTy->isStructTy())
1209      return false; // TODO: Handle multiple return values.
1210
1211    if (!CastInst::isBitCastable(NewRetTy, OldRetTy)) {
1212      if (Callee->isDeclaration())
1213        return false;   // Cannot transform this return value.
1214
1215      if (!Caller->use_empty() &&
1216          // void -> non-void is handled specially
1217          !NewRetTy->isVoidTy())
1218      return false;   // Cannot transform this return value.
1219    }
1220
1221    if (!CallerPAL.isEmpty() && !Caller->use_empty()) {
1222      AttrBuilder RAttrs(CallerPAL, AttributeSet::ReturnIndex);
1223      if (RAttrs.
1224          hasAttributes(AttributeFuncs::
1225                        typeIncompatible(NewRetTy, AttributeSet::ReturnIndex),
1226                        AttributeSet::ReturnIndex))
1227        return false;   // Attribute not compatible with transformed value.
1228    }
1229
1230    // If the callsite is an invoke instruction, and the return value is used by
1231    // a PHI node in a successor, we cannot change the return type of the call
1232    // because there is no place to put the cast instruction (without breaking
1233    // the critical edge).  Bail out in this case.
1234    if (!Caller->use_empty())
1235      if (InvokeInst *II = dyn_cast<InvokeInst>(Caller))
1236        for (User *U : II->users())
1237          if (PHINode *PN = dyn_cast<PHINode>(U))
1238            if (PN->getParent() == II->getNormalDest() ||
1239                PN->getParent() == II->getUnwindDest())
1240              return false;
1241  }
1242
1243  unsigned NumActualArgs = CS.arg_size();
1244  unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs);
1245
1246  CallSite::arg_iterator AI = CS.arg_begin();
1247  for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) {
1248    Type *ParamTy = FT->getParamType(i);
1249    Type *ActTy = (*AI)->getType();
1250
1251    if (!CastInst::isBitCastable(ActTy, ParamTy))
1252      return false;   // Cannot transform this parameter value.
1253
1254    if (AttrBuilder(CallerPAL.getParamAttributes(i + 1), i + 1).
1255          hasAttributes(AttributeFuncs::
1256                        typeIncompatible(ParamTy, i + 1), i + 1))
1257      return false;   // Attribute not compatible with transformed value.
1258
1259    if (CS.isInAllocaArgument(i))
1260      return false;   // Cannot transform to and from inalloca.
1261
1262    // If the parameter is passed as a byval argument, then we have to have a
1263    // sized type and the sized type has to have the same size as the old type.
1264    if (ParamTy != ActTy &&
1265        CallerPAL.getParamAttributes(i + 1).hasAttribute(i + 1,
1266                                                         Attribute::ByVal)) {
1267      PointerType *ParamPTy = dyn_cast<PointerType>(ParamTy);
1268      if (!ParamPTy || !ParamPTy->getElementType()->isSized() || !DL)
1269        return false;
1270
1271      Type *CurElTy = ActTy->getPointerElementType();
1272      if (DL->getTypeAllocSize(CurElTy) !=
1273          DL->getTypeAllocSize(ParamPTy->getElementType()))
1274        return false;
1275    }
1276  }
1277
1278  if (Callee->isDeclaration()) {
1279    // Do not delete arguments unless we have a function body.
1280    if (FT->getNumParams() < NumActualArgs && !FT->isVarArg())
1281      return false;
1282
1283    // If the callee is just a declaration, don't change the varargsness of the
1284    // call.  We don't want to introduce a varargs call where one doesn't
1285    // already exist.
1286    PointerType *APTy = cast<PointerType>(CS.getCalledValue()->getType());
1287    if (FT->isVarArg()!=cast<FunctionType>(APTy->getElementType())->isVarArg())
1288      return false;
1289
1290    // If both the callee and the cast type are varargs, we still have to make
1291    // sure the number of fixed parameters are the same or we have the same
1292    // ABI issues as if we introduce a varargs call.
1293    if (FT->isVarArg() &&
1294        cast<FunctionType>(APTy->getElementType())->isVarArg() &&
1295        FT->getNumParams() !=
1296        cast<FunctionType>(APTy->getElementType())->getNumParams())
1297      return false;
1298  }
1299
1300  if (FT->getNumParams() < NumActualArgs && FT->isVarArg() &&
1301      !CallerPAL.isEmpty())
1302    // In this case we have more arguments than the new function type, but we
1303    // won't be dropping them.  Check that these extra arguments have attributes
1304    // that are compatible with being a vararg call argument.
1305    for (unsigned i = CallerPAL.getNumSlots(); i; --i) {
1306      unsigned Index = CallerPAL.getSlotIndex(i - 1);
1307      if (Index <= FT->getNumParams())
1308        break;
1309
1310      // Check if it has an attribute that's incompatible with varargs.
1311      AttributeSet PAttrs = CallerPAL.getSlotAttributes(i - 1);
1312      if (PAttrs.hasAttribute(Index, Attribute::StructRet))
1313        return false;
1314    }
1315
1316
1317  // Okay, we decided that this is a safe thing to do: go ahead and start
1318  // inserting cast instructions as necessary.
1319  std::vector<Value*> Args;
1320  Args.reserve(NumActualArgs);
1321  SmallVector<AttributeSet, 8> attrVec;
1322  attrVec.reserve(NumCommonArgs);
1323
1324  // Get any return attributes.
1325  AttrBuilder RAttrs(CallerPAL, AttributeSet::ReturnIndex);
1326
1327  // If the return value is not being used, the type may not be compatible
1328  // with the existing attributes.  Wipe out any problematic attributes.
1329  RAttrs.
1330    removeAttributes(AttributeFuncs::
1331                     typeIncompatible(NewRetTy, AttributeSet::ReturnIndex),
1332                     AttributeSet::ReturnIndex);
1333
1334  // Add the new return attributes.
1335  if (RAttrs.hasAttributes())
1336    attrVec.push_back(AttributeSet::get(Caller->getContext(),
1337                                        AttributeSet::ReturnIndex, RAttrs));
1338
1339  AI = CS.arg_begin();
1340  for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) {
1341    Type *ParamTy = FT->getParamType(i);
1342
1343    if ((*AI)->getType() == ParamTy) {
1344      Args.push_back(*AI);
1345    } else {
1346      Args.push_back(Builder->CreateBitCast(*AI, ParamTy));
1347    }
1348
1349    // Add any parameter attributes.
1350    AttrBuilder PAttrs(CallerPAL.getParamAttributes(i + 1), i + 1);
1351    if (PAttrs.hasAttributes())
1352      attrVec.push_back(AttributeSet::get(Caller->getContext(), i + 1,
1353                                          PAttrs));
1354  }
1355
1356  // If the function takes more arguments than the call was taking, add them
1357  // now.
1358  for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i)
1359    Args.push_back(Constant::getNullValue(FT->getParamType(i)));
1360
1361  // If we are removing arguments to the function, emit an obnoxious warning.
1362  if (FT->getNumParams() < NumActualArgs) {
1363    // TODO: if (!FT->isVarArg()) this call may be unreachable. PR14722
1364    if (FT->isVarArg()) {
1365      // Add all of the arguments in their promoted form to the arg list.
1366      for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) {
1367        Type *PTy = getPromotedType((*AI)->getType());
1368        if (PTy != (*AI)->getType()) {
1369          // Must promote to pass through va_arg area!
1370          Instruction::CastOps opcode =
1371            CastInst::getCastOpcode(*AI, false, PTy, false);
1372          Args.push_back(Builder->CreateCast(opcode, *AI, PTy));
1373        } else {
1374          Args.push_back(*AI);
1375        }
1376
1377        // Add any parameter attributes.
1378        AttrBuilder PAttrs(CallerPAL.getParamAttributes(i + 1), i + 1);
1379        if (PAttrs.hasAttributes())
1380          attrVec.push_back(AttributeSet::get(FT->getContext(), i + 1,
1381                                              PAttrs));
1382      }
1383    }
1384  }
1385
1386  AttributeSet FnAttrs = CallerPAL.getFnAttributes();
1387  if (CallerPAL.hasAttributes(AttributeSet::FunctionIndex))
1388    attrVec.push_back(AttributeSet::get(Callee->getContext(), FnAttrs));
1389
1390  if (NewRetTy->isVoidTy())
1391    Caller->setName("");   // Void type should not have a name.
1392
1393  const AttributeSet &NewCallerPAL = AttributeSet::get(Callee->getContext(),
1394                                                       attrVec);
1395
1396  Instruction *NC;
1397  if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
1398    NC = Builder->CreateInvoke(Callee, II->getNormalDest(),
1399                               II->getUnwindDest(), Args);
1400    NC->takeName(II);
1401    cast<InvokeInst>(NC)->setCallingConv(II->getCallingConv());
1402    cast<InvokeInst>(NC)->setAttributes(NewCallerPAL);
1403  } else {
1404    CallInst *CI = cast<CallInst>(Caller);
1405    NC = Builder->CreateCall(Callee, Args);
1406    NC->takeName(CI);
1407    if (CI->isTailCall())
1408      cast<CallInst>(NC)->setTailCall();
1409    cast<CallInst>(NC)->setCallingConv(CI->getCallingConv());
1410    cast<CallInst>(NC)->setAttributes(NewCallerPAL);
1411  }
1412
1413  // Insert a cast of the return type as necessary.
1414  Value *NV = NC;
1415  if (OldRetTy != NV->getType() && !Caller->use_empty()) {
1416    if (!NV->getType()->isVoidTy()) {
1417      NV = NC = CastInst::Create(CastInst::BitCast, NC, OldRetTy);
1418      NC->setDebugLoc(Caller->getDebugLoc());
1419
1420      // If this is an invoke instruction, we should insert it after the first
1421      // non-phi, instruction in the normal successor block.
1422      if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
1423        BasicBlock::iterator I = II->getNormalDest()->getFirstInsertionPt();
1424        InsertNewInstBefore(NC, *I);
1425      } else {
1426        // Otherwise, it's a call, just insert cast right after the call.
1427        InsertNewInstBefore(NC, *Caller);
1428      }
1429      Worklist.AddUsersToWorkList(*Caller);
1430    } else {
1431      NV = UndefValue::get(Caller->getType());
1432    }
1433  }
1434
1435  if (!Caller->use_empty())
1436    ReplaceInstUsesWith(*Caller, NV);
1437  else if (Caller->hasValueHandle())
1438    ValueHandleBase::ValueIsRAUWd(Caller, NV);
1439
1440  EraseInstFromFunction(*Caller);
1441  return true;
1442}
1443
1444// transformCallThroughTrampoline - Turn a call to a function created by
1445// init_trampoline / adjust_trampoline intrinsic pair into a direct call to the
1446// underlying function.
1447//
1448Instruction *
1449InstCombiner::transformCallThroughTrampoline(CallSite CS,
1450                                             IntrinsicInst *Tramp) {
1451  Value *Callee = CS.getCalledValue();
1452  PointerType *PTy = cast<PointerType>(Callee->getType());
1453  FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1454  const AttributeSet &Attrs = CS.getAttributes();
1455
1456  // If the call already has the 'nest' attribute somewhere then give up -
1457  // otherwise 'nest' would occur twice after splicing in the chain.
1458  if (Attrs.hasAttrSomewhere(Attribute::Nest))
1459    return nullptr;
1460
1461  assert(Tramp &&
1462         "transformCallThroughTrampoline called with incorrect CallSite.");
1463
1464  Function *NestF =cast<Function>(Tramp->getArgOperand(1)->stripPointerCasts());
1465  PointerType *NestFPTy = cast<PointerType>(NestF->getType());
1466  FunctionType *NestFTy = cast<FunctionType>(NestFPTy->getElementType());
1467
1468  const AttributeSet &NestAttrs = NestF->getAttributes();
1469  if (!NestAttrs.isEmpty()) {
1470    unsigned NestIdx = 1;
1471    Type *NestTy = nullptr;
1472    AttributeSet NestAttr;
1473
1474    // Look for a parameter marked with the 'nest' attribute.
1475    for (FunctionType::param_iterator I = NestFTy->param_begin(),
1476         E = NestFTy->param_end(); I != E; ++NestIdx, ++I)
1477      if (NestAttrs.hasAttribute(NestIdx, Attribute::Nest)) {
1478        // Record the parameter type and any other attributes.
1479        NestTy = *I;
1480        NestAttr = NestAttrs.getParamAttributes(NestIdx);
1481        break;
1482      }
1483
1484    if (NestTy) {
1485      Instruction *Caller = CS.getInstruction();
1486      std::vector<Value*> NewArgs;
1487      NewArgs.reserve(CS.arg_size() + 1);
1488
1489      SmallVector<AttributeSet, 8> NewAttrs;
1490      NewAttrs.reserve(Attrs.getNumSlots() + 1);
1491
1492      // Insert the nest argument into the call argument list, which may
1493      // mean appending it.  Likewise for attributes.
1494
1495      // Add any result attributes.
1496      if (Attrs.hasAttributes(AttributeSet::ReturnIndex))
1497        NewAttrs.push_back(AttributeSet::get(Caller->getContext(),
1498                                             Attrs.getRetAttributes()));
1499
1500      {
1501        unsigned Idx = 1;
1502        CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
1503        do {
1504          if (Idx == NestIdx) {
1505            // Add the chain argument and attributes.
1506            Value *NestVal = Tramp->getArgOperand(2);
1507            if (NestVal->getType() != NestTy)
1508              NestVal = Builder->CreateBitCast(NestVal, NestTy, "nest");
1509            NewArgs.push_back(NestVal);
1510            NewAttrs.push_back(AttributeSet::get(Caller->getContext(),
1511                                                 NestAttr));
1512          }
1513
1514          if (I == E)
1515            break;
1516
1517          // Add the original argument and attributes.
1518          NewArgs.push_back(*I);
1519          AttributeSet Attr = Attrs.getParamAttributes(Idx);
1520          if (Attr.hasAttributes(Idx)) {
1521            AttrBuilder B(Attr, Idx);
1522            NewAttrs.push_back(AttributeSet::get(Caller->getContext(),
1523                                                 Idx + (Idx >= NestIdx), B));
1524          }
1525
1526          ++Idx, ++I;
1527        } while (1);
1528      }
1529
1530      // Add any function attributes.
1531      if (Attrs.hasAttributes(AttributeSet::FunctionIndex))
1532        NewAttrs.push_back(AttributeSet::get(FTy->getContext(),
1533                                             Attrs.getFnAttributes()));
1534
1535      // The trampoline may have been bitcast to a bogus type (FTy).
1536      // Handle this by synthesizing a new function type, equal to FTy
1537      // with the chain parameter inserted.
1538
1539      std::vector<Type*> NewTypes;
1540      NewTypes.reserve(FTy->getNumParams()+1);
1541
1542      // Insert the chain's type into the list of parameter types, which may
1543      // mean appending it.
1544      {
1545        unsigned Idx = 1;
1546        FunctionType::param_iterator I = FTy->param_begin(),
1547          E = FTy->param_end();
1548
1549        do {
1550          if (Idx == NestIdx)
1551            // Add the chain's type.
1552            NewTypes.push_back(NestTy);
1553
1554          if (I == E)
1555            break;
1556
1557          // Add the original type.
1558          NewTypes.push_back(*I);
1559
1560          ++Idx, ++I;
1561        } while (1);
1562      }
1563
1564      // Replace the trampoline call with a direct call.  Let the generic
1565      // code sort out any function type mismatches.
1566      FunctionType *NewFTy = FunctionType::get(FTy->getReturnType(), NewTypes,
1567                                                FTy->isVarArg());
1568      Constant *NewCallee =
1569        NestF->getType() == PointerType::getUnqual(NewFTy) ?
1570        NestF : ConstantExpr::getBitCast(NestF,
1571                                         PointerType::getUnqual(NewFTy));
1572      const AttributeSet &NewPAL =
1573          AttributeSet::get(FTy->getContext(), NewAttrs);
1574
1575      Instruction *NewCaller;
1576      if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
1577        NewCaller = InvokeInst::Create(NewCallee,
1578                                       II->getNormalDest(), II->getUnwindDest(),
1579                                       NewArgs);
1580        cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv());
1581        cast<InvokeInst>(NewCaller)->setAttributes(NewPAL);
1582      } else {
1583        NewCaller = CallInst::Create(NewCallee, NewArgs);
1584        if (cast<CallInst>(Caller)->isTailCall())
1585          cast<CallInst>(NewCaller)->setTailCall();
1586        cast<CallInst>(NewCaller)->
1587          setCallingConv(cast<CallInst>(Caller)->getCallingConv());
1588        cast<CallInst>(NewCaller)->setAttributes(NewPAL);
1589      }
1590
1591      return NewCaller;
1592    }
1593  }
1594
1595  // Replace the trampoline call with a direct call.  Since there is no 'nest'
1596  // parameter, there is no need to adjust the argument list.  Let the generic
1597  // code sort out any function type mismatches.
1598  Constant *NewCallee =
1599    NestF->getType() == PTy ? NestF :
1600                              ConstantExpr::getBitCast(NestF, PTy);
1601  CS.setCalledFunction(NewCallee);
1602  return CS.getInstruction();
1603}
1604