LLVM  16.0.0git
ArgumentPromotion.cpp
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1 //===- ArgumentPromotion.cpp - Promote by-reference arguments -------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This pass promotes "by reference" arguments to be "by value" arguments. In
10 // practice, this means looking for internal functions that have pointer
11 // arguments. If it can prove, through the use of alias analysis, that an
12 // argument is *only* loaded, then it can pass the value into the function
13 // instead of the address of the value. This can cause recursive simplification
14 // of code and lead to the elimination of allocas (especially in C++ template
15 // code like the STL).
16 //
17 // This pass also handles aggregate arguments that are passed into a function,
18 // scalarizing them if the elements of the aggregate are only loaded. Note that
19 // by default it refuses to scalarize aggregates which would require passing in
20 // more than three operands to the function, because passing thousands of
21 // operands for a large array or structure is unprofitable! This limit can be
22 // configured or disabled, however.
23 //
24 // Note that this transformation could also be done for arguments that are only
25 // stored to (returning the value instead), but does not currently. This case
26 // would be best handled when and if LLVM begins supporting multiple return
27 // values from functions.
28 //
29 //===----------------------------------------------------------------------===//
30 
32 
34 #include "llvm/ADT/STLExtras.h"
35 #include "llvm/ADT/ScopeExit.h"
36 #include "llvm/ADT/SmallPtrSet.h"
37 #include "llvm/ADT/SmallVector.h"
38 #include "llvm/ADT/Statistic.h"
39 #include "llvm/ADT/Twine.h"
43 #include "llvm/Analysis/Loads.h"
47 #include "llvm/IR/Argument.h"
48 #include "llvm/IR/Attributes.h"
49 #include "llvm/IR/BasicBlock.h"
50 #include "llvm/IR/CFG.h"
51 #include "llvm/IR/Constants.h"
52 #include "llvm/IR/DataLayout.h"
53 #include "llvm/IR/DerivedTypes.h"
54 #include "llvm/IR/Dominators.h"
55 #include "llvm/IR/Function.h"
56 #include "llvm/IR/IRBuilder.h"
57 #include "llvm/IR/InstrTypes.h"
58 #include "llvm/IR/Instruction.h"
59 #include "llvm/IR/Instructions.h"
60 #include "llvm/IR/Metadata.h"
61 #include "llvm/IR/NoFolder.h"
62 #include "llvm/IR/PassManager.h"
63 #include "llvm/IR/Type.h"
64 #include "llvm/IR/Use.h"
65 #include "llvm/IR/User.h"
66 #include "llvm/IR/Value.h"
67 #include "llvm/Support/Casting.h"
68 #include "llvm/Support/Debug.h"
71 #include <algorithm>
72 #include <cassert>
73 #include <cstdint>
74 #include <utility>
75 #include <vector>
76 
77 using namespace llvm;
78 
79 #define DEBUG_TYPE "argpromotion"
80 
81 STATISTIC(NumArgumentsPromoted, "Number of pointer arguments promoted");
82 STATISTIC(NumArgumentsDead, "Number of dead pointer args eliminated");
83 
84 namespace {
85 
86 struct ArgPart {
87  Type *Ty;
88  Align Alignment;
89  /// A representative guaranteed-executed load or store instruction for use by
90  /// metadata transfer.
91  Instruction *MustExecInstr;
92 };
93 
94 using OffsetAndArgPart = std::pair<int64_t, ArgPart>;
95 
96 } // end anonymous namespace
97 
99  Value *Ptr, Type *ResElemTy, int64_t Offset) {
100  // For non-opaque pointers, try to create a "nice" GEP if possible, otherwise
101  // fall back to an i8 GEP to a specific offset.
102  unsigned AddrSpace = Ptr->getType()->getPointerAddressSpace();
103  APInt OrigOffset(DL.getIndexTypeSizeInBits(Ptr->getType()), Offset);
104  if (!Ptr->getType()->isOpaquePointerTy()) {
105  Type *OrigElemTy = Ptr->getType()->getNonOpaquePointerElementType();
106  if (OrigOffset == 0 && OrigElemTy == ResElemTy)
107  return Ptr;
108 
109  if (OrigElemTy->isSized()) {
110  APInt TmpOffset = OrigOffset;
111  Type *TmpTy = OrigElemTy;
112  SmallVector<APInt> IntIndices =
113  DL.getGEPIndicesForOffset(TmpTy, TmpOffset);
114  if (TmpOffset == 0) {
115  // Try to add trailing zero indices to reach the right type.
116  while (TmpTy != ResElemTy) {
117  Type *NextTy = GetElementPtrInst::getTypeAtIndex(TmpTy, (uint64_t)0);
118  if (!NextTy)
119  break;
120 
121  IntIndices.push_back(APInt::getZero(
122  isa<StructType>(TmpTy) ? 32 : OrigOffset.getBitWidth()));
123  TmpTy = NextTy;
124  }
125 
126  SmallVector<Value *> Indices;
127  for (const APInt &Index : IntIndices)
128  Indices.push_back(IRB.getInt(Index));
129 
130  if (OrigOffset != 0 || TmpTy == ResElemTy) {
131  Ptr = IRB.CreateGEP(OrigElemTy, Ptr, Indices);
132  return IRB.CreateBitCast(Ptr, ResElemTy->getPointerTo(AddrSpace));
133  }
134  }
135  }
136  }
137 
138  if (OrigOffset != 0) {
139  Ptr = IRB.CreateBitCast(Ptr, IRB.getInt8PtrTy(AddrSpace));
140  Ptr = IRB.CreateGEP(IRB.getInt8Ty(), Ptr, IRB.getInt(OrigOffset));
141  }
142  return IRB.CreateBitCast(Ptr, ResElemTy->getPointerTo(AddrSpace));
143 }
144 
145 /// DoPromotion - This method actually performs the promotion of the specified
146 /// arguments, and returns the new function. At this point, we know that it's
147 /// safe to do so.
148 static Function *
151  &ArgsToPromote) {
152  // Start by computing a new prototype for the function, which is the same as
153  // the old function, but has modified arguments.
154  FunctionType *FTy = F->getFunctionType();
155  std::vector<Type *> Params;
156 
157  // Attribute - Keep track of the parameter attributes for the arguments
158  // that we are *not* promoting. For the ones that we do promote, the parameter
159  // attributes are lost
160  SmallVector<AttributeSet, 8> ArgAttrVec;
161  AttributeList PAL = F->getAttributes();
162 
163  // First, determine the new argument list
164  unsigned ArgNo = 0;
165  for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E;
166  ++I, ++ArgNo) {
167  if (!ArgsToPromote.count(&*I)) {
168  // Unchanged argument
169  Params.push_back(I->getType());
170  ArgAttrVec.push_back(PAL.getParamAttrs(ArgNo));
171  } else if (I->use_empty()) {
172  // Dead argument (which are always marked as promotable)
173  ++NumArgumentsDead;
174  } else {
175  const auto &ArgParts = ArgsToPromote.find(&*I)->second;
176  for (const auto &Pair : ArgParts) {
177  Params.push_back(Pair.second.Ty);
178  ArgAttrVec.push_back(AttributeSet());
179  }
180  ++NumArgumentsPromoted;
181  }
182  }
183 
184  Type *RetTy = FTy->getReturnType();
185 
186  // Construct the new function type using the new arguments.
187  FunctionType *NFTy = FunctionType::get(RetTy, Params, FTy->isVarArg());
188 
189  // Create the new function body and insert it into the module.
190  Function *NF = Function::Create(NFTy, F->getLinkage(), F->getAddressSpace(),
191  F->getName());
192  NF->copyAttributesFrom(F);
193  NF->copyMetadata(F, 0);
194 
195  // The new function will have the !dbg metadata copied from the original
196  // function. The original function may not be deleted, and dbg metadata need
197  // to be unique, so we need to drop it.
198  F->setSubprogram(nullptr);
199 
200  LLVM_DEBUG(dbgs() << "ARG PROMOTION: Promoting to:" << *NF << "\n"
201  << "From: " << *F);
202 
203  uint64_t LargestVectorWidth = 0;
204  for (auto *I : Params)
205  if (auto *VT = dyn_cast<llvm::VectorType>(I))
206  LargestVectorWidth = std::max(
207  LargestVectorWidth, VT->getPrimitiveSizeInBits().getKnownMinSize());
208 
209  // Recompute the parameter attributes list based on the new arguments for
210  // the function.
211  NF->setAttributes(AttributeList::get(F->getContext(), PAL.getFnAttrs(),
212  PAL.getRetAttrs(), ArgAttrVec));
213  AttributeFuncs::updateMinLegalVectorWidthAttr(*NF, LargestVectorWidth);
214  ArgAttrVec.clear();
215 
216  F->getParent()->getFunctionList().insert(F->getIterator(), NF);
217  NF->takeName(F);
218 
219  // Loop over all the callers of the function, transforming the call sites to
220  // pass in the loaded pointers.
222  const DataLayout &DL = F->getParent()->getDataLayout();
223  while (!F->use_empty()) {
224  CallBase &CB = cast<CallBase>(*F->user_back());
225  assert(CB.getCalledFunction() == F);
226  const AttributeList &CallPAL = CB.getAttributes();
227  IRBuilder<NoFolder> IRB(&CB);
228 
229  // Loop over the operands, inserting GEP and loads in the caller as
230  // appropriate.
231  auto *AI = CB.arg_begin();
232  ArgNo = 0;
233  for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E;
234  ++I, ++AI, ++ArgNo) {
235  if (!ArgsToPromote.count(&*I)) {
236  Args.push_back(*AI); // Unmodified argument
237  ArgAttrVec.push_back(CallPAL.getParamAttrs(ArgNo));
238  } else if (!I->use_empty()) {
239  Value *V = *AI;
240  const auto &ArgParts = ArgsToPromote.find(&*I)->second;
241  for (const auto &Pair : ArgParts) {
242  LoadInst *LI = IRB.CreateAlignedLoad(
243  Pair.second.Ty,
244  createByteGEP(IRB, DL, V, Pair.second.Ty, Pair.first),
245  Pair.second.Alignment, V->getName() + ".val");
246  if (Pair.second.MustExecInstr) {
247  LI->setAAMetadata(Pair.second.MustExecInstr->getAAMetadata());
248  LI->copyMetadata(*Pair.second.MustExecInstr,
249  {LLVMContext::MD_range, LLVMContext::MD_nonnull,
250  LLVMContext::MD_dereferenceable,
251  LLVMContext::MD_dereferenceable_or_null,
252  LLVMContext::MD_align, LLVMContext::MD_noundef,
253  LLVMContext::MD_nontemporal});
254  }
255  Args.push_back(LI);
256  ArgAttrVec.push_back(AttributeSet());
257  }
258  }
259  }
260 
261  // Push any varargs arguments on the list.
262  for (; AI != CB.arg_end(); ++AI, ++ArgNo) {
263  Args.push_back(*AI);
264  ArgAttrVec.push_back(CallPAL.getParamAttrs(ArgNo));
265  }
266 
268  CB.getOperandBundlesAsDefs(OpBundles);
269 
270  CallBase *NewCS = nullptr;
271  if (InvokeInst *II = dyn_cast<InvokeInst>(&CB)) {
272  NewCS = InvokeInst::Create(NF, II->getNormalDest(), II->getUnwindDest(),
273  Args, OpBundles, "", &CB);
274  } else {
275  auto *NewCall = CallInst::Create(NF, Args, OpBundles, "", &CB);
276  NewCall->setTailCallKind(cast<CallInst>(&CB)->getTailCallKind());
277  NewCS = NewCall;
278  }
279  NewCS->setCallingConv(CB.getCallingConv());
280  NewCS->setAttributes(AttributeList::get(F->getContext(),
281  CallPAL.getFnAttrs(),
282  CallPAL.getRetAttrs(), ArgAttrVec));
283  NewCS->copyMetadata(CB, {LLVMContext::MD_prof, LLVMContext::MD_dbg});
284  Args.clear();
285  ArgAttrVec.clear();
286 
288  LargestVectorWidth);
289 
290  if (!CB.use_empty()) {
291  CB.replaceAllUsesWith(NewCS);
292  NewCS->takeName(&CB);
293  }
294 
295  // Finally, remove the old call from the program, reducing the use-count of
296  // F.
297  CB.eraseFromParent();
298  }
299 
300  // Since we have now created the new function, splice the body of the old
301  // function right into the new function, leaving the old rotting hulk of the
302  // function empty.
303  NF->getBasicBlockList().splice(NF->begin(), F->getBasicBlockList());
304 
305  // We will collect all the new created allocas to promote them into registers
306  // after the following loop
308 
309  // Loop over the argument list, transferring uses of the old arguments over to
310  // the new arguments, also transferring over the names as well.
312  for (Argument &Arg : F->args()) {
313  if (!ArgsToPromote.count(&Arg)) {
314  // If this is an unmodified argument, move the name and users over to the
315  // new version.
316  Arg.replaceAllUsesWith(&*I2);
317  I2->takeName(&Arg);
318  ++I2;
319  continue;
320  }
321 
322  // There potentially are metadata uses for things like llvm.dbg.value.
323  // Replace them with undef, after handling the other regular uses.
324  auto RauwUndefMetadata = make_scope_exit(
325  [&]() { Arg.replaceAllUsesWith(UndefValue::get(Arg.getType())); });
326 
327  if (Arg.use_empty())
328  continue;
329 
330  // Otherwise, if we promoted this argument, we have to create an alloca in
331  // the callee for every promotable part and store each of the new incoming
332  // arguments into the corresponding alloca, what lets the old code (the
333  // store instructions if they are allowed especially) a chance to work as
334  // before.
335  assert(Arg.getType()->isPointerTy() &&
336  "Only arguments with a pointer type are promotable");
337 
338  IRBuilder<NoFolder> IRB(&NF->begin()->front());
339 
340  // Add only the promoted elements, so parts from ArgsToPromote
342  for (const auto &Pair : ArgsToPromote.find(&Arg)->second) {
343  int64_t Offset = Pair.first;
344  const ArgPart &Part = Pair.second;
345 
346  Argument *NewArg = I2++;
347  NewArg->setName(Arg.getName() + "." + Twine(Offset) + ".val");
348 
349  AllocaInst *NewAlloca = IRB.CreateAlloca(
350  Part.Ty, nullptr, Arg.getName() + "." + Twine(Offset) + ".allc");
351  NewAlloca->setAlignment(Pair.second.Alignment);
352  IRB.CreateAlignedStore(NewArg, NewAlloca, Pair.second.Alignment);
353 
354  // Collect the alloca to retarget the users to
355  OffsetToAlloca.insert({Offset, NewAlloca});
356  }
357 
358  auto GetAlloca = [&](Value *Ptr) {
359  APInt Offset(DL.getIndexTypeSizeInBits(Ptr->getType()), 0);
360  Ptr = Ptr->stripAndAccumulateConstantOffsets(DL, Offset,
361  /* AllowNonInbounds */ true);
362  assert(Ptr == &Arg && "Not constant offset from arg?");
363  return OffsetToAlloca.lookup(Offset.getSExtValue());
364  };
365 
366  // Cleanup the code from the dead instructions: GEPs and BitCasts in between
367  // the original argument and its users: loads and stores. Retarget every
368  // user to the new created alloca.
369  SmallVector<Value *, 16> Worklist;
371  append_range(Worklist, Arg.users());
372  while (!Worklist.empty()) {
373  Value *V = Worklist.pop_back_val();
374  if (isa<BitCastInst>(V) || isa<GetElementPtrInst>(V)) {
375  DeadInsts.push_back(cast<Instruction>(V));
376  append_range(Worklist, V->users());
377  continue;
378  }
379 
380  if (auto *LI = dyn_cast<LoadInst>(V)) {
381  Value *Ptr = LI->getPointerOperand();
382  LI->setOperand(LoadInst::getPointerOperandIndex(), GetAlloca(Ptr));
383  continue;
384  }
385 
386  if (auto *SI = dyn_cast<StoreInst>(V)) {
387  assert(!SI->isVolatile() && "Volatile operations can't be promoted.");
388  Value *Ptr = SI->getPointerOperand();
389  SI->setOperand(StoreInst::getPointerOperandIndex(), GetAlloca(Ptr));
390  continue;
391  }
392 
393  llvm_unreachable("Unexpected user");
394  }
395 
396  for (Instruction *I : DeadInsts) {
397  I->replaceAllUsesWith(PoisonValue::get(I->getType()));
398  I->eraseFromParent();
399  }
400 
401  // Collect the allocas for promotion
402  for (const auto &Pair : OffsetToAlloca) {
403  assert(isAllocaPromotable(Pair.second) &&
404  "By design, only promotable allocas should be produced.");
405  Allocas.push_back(Pair.second);
406  }
407  }
408 
409  LLVM_DEBUG(dbgs() << "ARG PROMOTION: " << Allocas.size()
410  << " alloca(s) are promotable by Mem2Reg\n");
411 
412  if (!Allocas.empty()) {
413  // And we are able to call the `promoteMemoryToRegister()` function.
414  // Our earlier checks have ensured that PromoteMemToReg() will
415  // succeed.
416  auto &DT = FAM.getResult<DominatorTreeAnalysis>(*NF);
417  auto &AC = FAM.getResult<AssumptionAnalysis>(*NF);
418  PromoteMemToReg(Allocas, DT, &AC);
419  }
420 
421  return NF;
422 }
423 
424 /// Return true if we can prove that all callees pass in a valid pointer for the
425 /// specified function argument.
427  Align NeededAlign,
428  uint64_t NeededDerefBytes) {
429  Function *Callee = Arg->getParent();
430  const DataLayout &DL = Callee->getParent()->getDataLayout();
431  APInt Bytes(64, NeededDerefBytes);
432 
433  // Check if the argument itself is marked dereferenceable and aligned.
434  if (isDereferenceableAndAlignedPointer(Arg, NeededAlign, Bytes, DL))
435  return true;
436 
437  // Look at all call sites of the function. At this point we know we only have
438  // direct callees.
439  return all_of(Callee->users(), [&](User *U) {
440  CallBase &CB = cast<CallBase>(*U);
441  return isDereferenceableAndAlignedPointer(CB.getArgOperand(Arg->getArgNo()),
442  NeededAlign, Bytes, DL);
443  });
444 }
445 
446 /// Determine that this argument is safe to promote, and find the argument
447 /// parts it can be promoted into.
448 static bool findArgParts(Argument *Arg, const DataLayout &DL, AAResults &AAR,
449  unsigned MaxElements, bool IsRecursive,
450  SmallVectorImpl<OffsetAndArgPart> &ArgPartsVec) {
451  // Quick exit for unused arguments
452  if (Arg->use_empty())
453  return true;
454 
455  // We can only promote this argument if all the uses are loads at known
456  // offsets.
457  //
458  // Promoting the argument causes it to be loaded in the caller
459  // unconditionally. This is only safe if we can prove that either the load
460  // would have happened in the callee anyway (ie, there is a load in the entry
461  // block) or the pointer passed in at every call site is guaranteed to be
462  // valid.
463  // In the former case, invalid loads can happen, but would have happened
464  // anyway, in the latter case, invalid loads won't happen. This prevents us
465  // from introducing an invalid load that wouldn't have happened in the
466  // original code.
467 
469  Align NeededAlign(1);
470  uint64_t NeededDerefBytes = 0;
471 
472  // And if this is a byval argument we also allow to have store instructions.
473  // Only handle in such way arguments with specified alignment;
474  // if it's unspecified, the actual alignment of the argument is
475  // target-specific.
476  bool AreStoresAllowed = Arg->getParamByValType() && Arg->getParamAlign();
477 
478  // An end user of a pointer argument is a load or store instruction.
479  // Returns std::nullopt if this load or store is not based on the argument.
480  // Return true if we can promote the instruction, false otherwise.
481  auto HandleEndUser = [&](auto *I, Type *Ty,
482  bool GuaranteedToExecute) -> std::optional<bool> {
483  // Don't promote volatile or atomic instructions.
484  if (!I->isSimple())
485  return false;
486 
487  Value *Ptr = I->getPointerOperand();
488  APInt Offset(DL.getIndexTypeSizeInBits(Ptr->getType()), 0);
489  Ptr = Ptr->stripAndAccumulateConstantOffsets(DL, Offset,
490  /* AllowNonInbounds */ true);
491  if (Ptr != Arg)
492  return std::nullopt;
493 
494  if (Offset.getSignificantBits() >= 64)
495  return false;
496 
497  TypeSize Size = DL.getTypeStoreSize(Ty);
498  // Don't try to promote scalable types.
499  if (Size.isScalable())
500  return false;
501 
502  // If this is a recursive function and one of the types is a pointer,
503  // then promoting it might lead to recursive promotion.
504  if (IsRecursive && Ty->isPointerTy())
505  return false;
506 
507  int64_t Off = Offset.getSExtValue();
508  auto Pair = ArgParts.try_emplace(
509  Off, ArgPart{Ty, I->getAlign(), GuaranteedToExecute ? I : nullptr});
510  ArgPart &Part = Pair.first->second;
511  bool OffsetNotSeenBefore = Pair.second;
512 
513  // We limit promotion to only promoting up to a fixed number of elements of
514  // the aggregate.
515  if (MaxElements > 0 && ArgParts.size() > MaxElements) {
516  LLVM_DEBUG(dbgs() << "ArgPromotion of " << *Arg << " failed: "
517  << "more than " << MaxElements << " parts\n");
518  return false;
519  }
520 
521  // For now, we only support loading/storing one specific type at a given
522  // offset.
523  if (Part.Ty != Ty) {
524  LLVM_DEBUG(dbgs() << "ArgPromotion of " << *Arg << " failed: "
525  << "accessed as both " << *Part.Ty << " and " << *Ty
526  << " at offset " << Off << "\n");
527  return false;
528  }
529 
530  // If this instruction is not guaranteed to execute, and we haven't seen a
531  // load or store at this offset before (or it had lower alignment), then we
532  // need to remember that requirement.
533  // Note that skipping instructions of previously seen offsets is only
534  // correct because we only allow a single type for a given offset, which
535  // also means that the number of accessed bytes will be the same.
536  if (!GuaranteedToExecute &&
537  (OffsetNotSeenBefore || Part.Alignment < I->getAlign())) {
538  // We won't be able to prove dereferenceability for negative offsets.
539  if (Off < 0)
540  return false;
541 
542  // If the offset is not aligned, an aligned base pointer won't help.
543  if (!isAligned(I->getAlign(), Off))
544  return false;
545 
546  NeededDerefBytes = std::max(NeededDerefBytes, Off + Size.getFixedValue());
547  NeededAlign = std::max(NeededAlign, I->getAlign());
548  }
549 
550  Part.Alignment = std::max(Part.Alignment, I->getAlign());
551  return true;
552  };
553 
554  // Look for loads and stores that are guaranteed to execute on entry.
555  for (Instruction &I : Arg->getParent()->getEntryBlock()) {
556  std::optional<bool> Res{};
557  if (LoadInst *LI = dyn_cast<LoadInst>(&I))
558  Res = HandleEndUser(LI, LI->getType(), /* GuaranteedToExecute */ true);
559  else if (StoreInst *SI = dyn_cast<StoreInst>(&I))
560  Res = HandleEndUser(SI, SI->getValueOperand()->getType(),
561  /* GuaranteedToExecute */ true);
562  if (Res && !*Res)
563  return false;
564 
566  break;
567  }
568 
569  // Now look at all loads of the argument. Remember the load instructions
570  // for the aliasing check below.
574  auto AppendUses = [&](const Value *V) {
575  for (const Use &U : V->uses())
576  if (Visited.insert(&U).second)
577  Worklist.push_back(&U);
578  };
579  AppendUses(Arg);
580  while (!Worklist.empty()) {
581  const Use *U = Worklist.pop_back_val();
582  Value *V = U->getUser();
583  if (isa<BitCastInst>(V)) {
584  AppendUses(V);
585  continue;
586  }
587 
588  if (auto *GEP = dyn_cast<GetElementPtrInst>(V)) {
589  if (!GEP->hasAllConstantIndices())
590  return false;
591  AppendUses(V);
592  continue;
593  }
594 
595  if (auto *LI = dyn_cast<LoadInst>(V)) {
596  if (!*HandleEndUser(LI, LI->getType(), /* GuaranteedToExecute */ false))
597  return false;
598  Loads.push_back(LI);
599  continue;
600  }
601 
602  // Stores are allowed for byval arguments
603  auto *SI = dyn_cast<StoreInst>(V);
604  if (AreStoresAllowed && SI &&
605  U->getOperandNo() == StoreInst::getPointerOperandIndex()) {
606  if (!*HandleEndUser(SI, SI->getValueOperand()->getType(),
607  /* GuaranteedToExecute */ false))
608  return false;
609  continue;
610  // Only stores TO the argument is allowed, all the other stores are
611  // unknown users
612  }
613 
614  // Unknown user.
615  LLVM_DEBUG(dbgs() << "ArgPromotion of " << *Arg << " failed: "
616  << "unknown user " << *V << "\n");
617  return false;
618  }
619 
620  if (NeededDerefBytes || NeededAlign > 1) {
621  // Try to prove a required deref / aligned requirement.
622  if (!allCallersPassValidPointerForArgument(Arg, NeededAlign,
623  NeededDerefBytes)) {
624  LLVM_DEBUG(dbgs() << "ArgPromotion of " << *Arg << " failed: "
625  << "not dereferenceable or aligned\n");
626  return false;
627  }
628  }
629 
630  if (ArgParts.empty())
631  return true; // No users, this is a dead argument.
632 
633  // Sort parts by offset.
634  append_range(ArgPartsVec, ArgParts);
635  sort(ArgPartsVec, llvm::less_first());
636 
637  // Make sure the parts are non-overlapping.
638  int64_t Offset = ArgPartsVec[0].first;
639  for (const auto &Pair : ArgPartsVec) {
640  if (Pair.first < Offset)
641  return false; // Overlap with previous part.
642 
643  Offset = Pair.first + DL.getTypeStoreSize(Pair.second.Ty);
644  }
645 
646  // If store instructions are allowed, the path from the entry of the function
647  // to each load may be not free of instructions that potentially invalidate
648  // the load, and this is an admissible situation.
649  if (AreStoresAllowed)
650  return true;
651 
652  // Okay, now we know that the argument is only used by load instructions, and
653  // it is safe to unconditionally perform all of them. Use alias analysis to
654  // check to see if the pointer is guaranteed to not be modified from entry of
655  // the function to each of the load instructions.
656 
657  // Because there could be several/many load instructions, remember which
658  // blocks we know to be transparent to the load.
660 
661  for (LoadInst *Load : Loads) {
662  // Check to see if the load is invalidated from the start of the block to
663  // the load itself.
664  BasicBlock *BB = Load->getParent();
665 
667  if (AAR.canInstructionRangeModRef(BB->front(), *Load, Loc, ModRefInfo::Mod))
668  return false; // Pointer is invalidated!
669 
670  // Now check every path from the entry block to the load for transparency.
671  // To do this, we perform a depth first search on the inverse CFG from the
672  // loading block.
673  for (BasicBlock *P : predecessors(BB)) {
674  for (BasicBlock *TranspBB : inverse_depth_first_ext(P, TranspBlocks))
675  if (AAR.canBasicBlockModify(*TranspBB, Loc))
676  return false;
677  }
678  }
679 
680  // If the path from the entry of the function to each load is free of
681  // instructions that potentially invalidate the load, we can make the
682  // transformation!
683  return true;
684 }
685 
686 /// Check if callers and callee agree on how promoted arguments would be
687 /// passed.
689  const TargetTransformInfo &TTI) {
690  return all_of(F.uses(), [&](const Use &U) {
691  CallBase *CB = dyn_cast<CallBase>(U.getUser());
692  if (!CB)
693  return false;
694 
695  const Function *Caller = CB->getCaller();
696  const Function *Callee = CB->getCalledFunction();
697  return TTI.areTypesABICompatible(Caller, Callee, Types);
698  });
699 }
700 
701 /// PromoteArguments - This method checks the specified function to see if there
702 /// are any promotable arguments and if it is safe to promote the function (for
703 /// example, all callers are direct). If safe to promote some arguments, it
704 /// calls the DoPromotion method.
706  unsigned MaxElements, bool IsRecursive) {
707  // Don't perform argument promotion for naked functions; otherwise we can end
708  // up removing parameters that are seemingly 'not used' as they are referred
709  // to in the assembly.
710  if (F->hasFnAttribute(Attribute::Naked))
711  return nullptr;
712 
713  // Make sure that it is local to this module.
714  if (!F->hasLocalLinkage())
715  return nullptr;
716 
717  // Don't promote arguments for variadic functions. Adding, removing, or
718  // changing non-pack parameters can change the classification of pack
719  // parameters. Frontends encode that classification at the call site in the
720  // IR, while in the callee the classification is determined dynamically based
721  // on the number of registers consumed so far.
722  if (F->isVarArg())
723  return nullptr;
724 
725  // Don't transform functions that receive inallocas, as the transformation may
726  // not be safe depending on calling convention.
727  if (F->getAttributes().hasAttrSomewhere(Attribute::InAlloca))
728  return nullptr;
729 
730  // First check: see if there are any pointer arguments! If not, quick exit.
731  SmallVector<Argument *, 16> PointerArgs;
732  for (Argument &I : F->args())
733  if (I.getType()->isPointerTy())
734  PointerArgs.push_back(&I);
735  if (PointerArgs.empty())
736  return nullptr;
737 
738  // Second check: make sure that all callers are direct callers. We can't
739  // transform functions that have indirect callers. Also see if the function
740  // is self-recursive.
741  for (Use &U : F->uses()) {
742  CallBase *CB = dyn_cast<CallBase>(U.getUser());
743  // Must be a direct call.
744  if (CB == nullptr || !CB->isCallee(&U) ||
745  CB->getFunctionType() != F->getFunctionType())
746  return nullptr;
747 
748  // Can't change signature of musttail callee
749  if (CB->isMustTailCall())
750  return nullptr;
751 
752  if (CB->getFunction() == F)
753  IsRecursive = true;
754  }
755 
756  // Can't change signature of musttail caller
757  // FIXME: Support promoting whole chain of musttail functions
758  for (BasicBlock &BB : *F)
759  if (BB.getTerminatingMustTailCall())
760  return nullptr;
761 
762  const DataLayout &DL = F->getParent()->getDataLayout();
763  auto &AAR = FAM.getResult<AAManager>(*F);
764  const auto &TTI = FAM.getResult<TargetIRAnalysis>(*F);
765 
766  // Check to see which arguments are promotable. If an argument is promotable,
767  // add it to ArgsToPromote.
769  for (Argument *PtrArg : PointerArgs) {
770  // Replace sret attribute with noalias. This reduces register pressure by
771  // avoiding a register copy.
772  if (PtrArg->hasStructRetAttr()) {
773  unsigned ArgNo = PtrArg->getArgNo();
774  F->removeParamAttr(ArgNo, Attribute::StructRet);
775  F->addParamAttr(ArgNo, Attribute::NoAlias);
776  for (Use &U : F->uses()) {
777  CallBase &CB = cast<CallBase>(*U.getUser());
778  CB.removeParamAttr(ArgNo, Attribute::StructRet);
779  CB.addParamAttr(ArgNo, Attribute::NoAlias);
780  }
781  }
782 
783  // If we can promote the pointer to its value.
785 
786  if (findArgParts(PtrArg, DL, AAR, MaxElements, IsRecursive, ArgParts)) {
788  for (const auto &Pair : ArgParts)
789  Types.push_back(Pair.second.Ty);
790 
791  if (areTypesABICompatible(Types, *F, TTI)) {
792  ArgsToPromote.insert({PtrArg, std::move(ArgParts)});
793  }
794  }
795  }
796 
797  // No promotable pointer arguments.
798  if (ArgsToPromote.empty())
799  return nullptr;
800 
801  return doPromotion(F, FAM, ArgsToPromote);
802 }
803 
806  LazyCallGraph &CG,
807  CGSCCUpdateResult &UR) {
808  bool Changed = false, LocalChange;
809 
810  // Iterate until we stop promoting from this SCC.
811  do {
812  LocalChange = false;
813 
815  AM.getResult<FunctionAnalysisManagerCGSCCProxy>(C, CG).getManager();
816 
817  bool IsRecursive = C.size() > 1;
818  for (LazyCallGraph::Node &N : C) {
819  Function &OldF = N.getFunction();
820  Function *NewF = promoteArguments(&OldF, FAM, MaxElements, IsRecursive);
821  if (!NewF)
822  continue;
823  LocalChange = true;
824 
825  // Directly substitute the functions in the call graph. Note that this
826  // requires the old function to be completely dead and completely
827  // replaced by the new function. It does no call graph updates, it merely
828  // swaps out the particular function mapped to a particular node in the
829  // graph.
830  C.getOuterRefSCC().replaceNodeFunction(N, *NewF);
831  FAM.clear(OldF, OldF.getName());
832  OldF.eraseFromParent();
833 
834  PreservedAnalyses FuncPA;
835  FuncPA.preserveSet<CFGAnalyses>();
836  for (auto *U : NewF->users()) {
837  auto *UserF = cast<CallBase>(U)->getFunction();
838  FAM.invalidate(*UserF, FuncPA);
839  }
840  }
841 
842  Changed |= LocalChange;
843  } while (LocalChange);
844 
845  if (!Changed)
846  return PreservedAnalyses::all();
847 
849  // We've cleared out analyses for deleted functions.
851  // We've manually invalidated analyses for functions we've modified.
853  return PA;
854 }
llvm::PreservedAnalyses
A set of analyses that are preserved following a run of a transformation pass.
Definition: PassManager.h:152
llvm::Argument
This class represents an incoming formal argument to a Function.
Definition: Argument.h:28
AssumptionCache.h
llvm::AAManager
A manager for alias analyses.
Definition: AliasAnalysis.h:881
llvm::Type::isSized
bool isSized(SmallPtrSetImpl< Type * > *Visited=nullptr) const
Return true if it makes sense to take the size of this type.
Definition: Type.h:283
llvm::TargetIRAnalysis
Analysis pass providing the TargetTransformInfo.
Definition: TargetTransformInfo.h:2592
llvm::isAligned
bool isAligned(Align Lhs, uint64_t SizeInBytes)
Checks that SizeInBytes is a multiple of the alignment.
Definition: Alignment.h:146
llvm::MemoryLocation::get
static MemoryLocation get(const LoadInst *LI)
Return a location with information about the memory reference by the given instruction.
Definition: MemoryLocation.cpp:36
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
llvm::CallBase::getOperandBundlesAsDefs
void getOperandBundlesAsDefs(SmallVectorImpl< OperandBundleDef > &Defs) const
Return the list of operand bundles attached to this instruction as a vector of OperandBundleDefs.
Definition: Instructions.cpp:417
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static InvokeInst * Create(FunctionType *Ty, Value *Func, BasicBlock *IfNormal, BasicBlock *IfException, ArrayRef< Value * > Args, const Twine &NameStr, Instruction *InsertBefore=nullptr)
Definition: Instructions.h:3853
NoFolder.h
llvm::IRBuilderBase::CreateAlignedStore
StoreInst * CreateAlignedStore(Value *Val, Value *Ptr, MaybeAlign Align, bool isVolatile=false)
Definition: IRBuilder.h:1724
llvm::DataLayout
A parsed version of the target data layout string in and methods for querying it.
Definition: DataLayout.h:113
Metadata.h
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PassT::Result & getResult(IRUnitT &IR, ExtraArgTs... ExtraArgs)
Get the result of an analysis pass for a given IR unit.
Definition: PassManager.h:774
llvm::Function::getBasicBlockList
const BasicBlockListType & getBasicBlockList() const
Get the underlying elements of the Function...
Definition: Function.h:684
Loads.h
llvm::Function
Definition: Function.h:60
llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, 4, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::lookup
ValueT lookup(const_arg_type_t< KeyT > Val) const
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Definition: DenseMap.h:197
llvm::AnalysisManager::invalidate
void invalidate(IRUnitT &IR, const PreservedAnalyses &PA)
Invalidate cached analyses for an IR unit.
Definition: PassManagerImpl.h:89
P
This currently compiles esp xmm0 movsd esp eax eax esp ret We should use not the dag combiner This is because dagcombine2 needs to be able to see through the X86ISD::Wrapper which DAGCombine can t really do The code for turning x load into a single vector load is target independent and should be moved to the dag combiner The code for turning x load into a vector load can only handle a direct load from a global or a direct load from the stack It should be generalized to handle any load from P
Definition: README-SSE.txt:411
llvm::Function::eraseFromParent
void eraseFromParent()
eraseFromParent - This method unlinks 'this' from the containing module and deletes it.
Definition: Function.cpp:368
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This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
Definition: SmallVector.h:1199
Statistic.h
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This pass provides access to the codegen interfaces that are needed for IR-level transformations.
Definition: TargetTransformInfo.h:173
llvm::IRBuilder
This provides a uniform API for creating instructions and inserting them into a basic block: either a...
Definition: IRBuilder.h:2533
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Definition: PassManager.h:90
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Definition: DenseMap.h:880
llvm::FunctionType::get
static FunctionType * get(Type *Result, ArrayRef< Type * > Params, bool isVarArg)
This static method is the primary way of constructing a FunctionType.
Definition: Type.cpp:361
ValueTracking.h
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static AttributeList get(LLVMContext &C, ArrayRef< std::pair< unsigned, Attribute >> Attrs)
Create an AttributeList with the specified parameters in it.
Definition: Attributes.cpp:1132
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Definition: PassBuilderBindings.cpp:59
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The instances of the Type class are immutable: once they are created, they are never changed.
Definition: Type.h:45
llvm::APInt::getBitWidth
unsigned getBitWidth() const
Return the number of bits in the APInt.
Definition: APInt.h:1431
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PromoteArguments - This method checks the specified function to see if there are any promotable argum...
Definition: ArgumentPromotion.cpp:705
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Definition: Attributes.h:432
llvm::CallBase::getAttributes
AttributeList getAttributes() const
Return the parameter attributes for this call.
Definition: InstrTypes.h:1474
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static unsigned getPointerOperandIndex()
Definition: Instructions.h:263
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Definition: InstrTypes.h:1254
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bool isCallee(Value::const_user_iterator UI) const
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Definition: InstrTypes.h:1407
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AttributeSet getFnAttrs() const
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Definition: Attributes.cpp:1469
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bool isMustTailCall() const
Tests if this call site must be tail call optimized.
Definition: Instructions.cpp:301
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SmallPtrSet - This class implements a set which is optimized for holding SmallSize or less elements.
Definition: SmallPtrSet.h:450
llvm::PromoteMemToReg
void PromoteMemToReg(ArrayRef< AllocaInst * > Allocas, DominatorTree &DT, AssumptionCache *AC=nullptr)
Promote the specified list of alloca instructions into scalar registers, inserting PHI nodes as appro...
Definition: PromoteMemoryToRegister.cpp:1107
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Definition: FileCheck.cpp:337
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Copy metadata from SrcInst to this instruction.
Definition: Instruction.cpp:878
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Definition: InstrTypes.h:1316
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Definition: IRBuilder.h:1705
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Adds the attribute to the indicated argument.
Definition: InstrTypes.h:1526
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@ Load
Definition: SparcInstrInfo.h:32
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Definition: IRBuilder.h:1671
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static APInt getZero(unsigned numBits)
Get the '0' value for the specified bit-width.
Definition: APInt.h:177
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Definition: Debug.h:101
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Definition: MD5.cpp:55
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Definition: ArgumentPromotion.cpp:804
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bool isVarArg() const
Definition: DerivedTypes.h:123
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Definition: BasicBlock.h:55
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Definition: Debug.cpp:163
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Definition: AMDGPULibCalls.cpp:187
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void removeParamAttr(unsigned ArgNo, Attribute::AttrKind Kind)
Removes the attribute from the given argument.
Definition: InstrTypes.h:1568
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Provide wrappers to std::all_of which take ranges instead of having to pass begin/end explicitly.
Definition: STLExtras.h:1734
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An SCC of the call graph.
Definition: LazyCallGraph.h:419
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Definition: AliasAnalysis.h:294
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Definition: IRBuilder.h:1764
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Definition: User.h:44
ArgumentPromotion.h
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Definition: STLExtras.h:1476
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(vector float) vec_cmpeq(*A, *B) C
Definition: README_ALTIVEC.txt:86
doPromotion
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DoPromotion - This method actually performs the promotion of the specified arguments,...
Definition: ArgumentPromotion.cpp:149
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Returns the function called, or null if this is an indirect function invocation or the function signa...
Definition: InstrTypes.h:1396
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Set the parameter attributes for this call.
Definition: InstrTypes.h:1478
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Clear any cached analysis results for a single unit of IR.
Definition: PassManagerImpl.h:36
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Definition: Instructions.h:1517
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@ SI
Definition: SIInstrInfo.cpp:7966
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Definition: Value.h:376
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Index
Definition: Dwarf.h:490
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Definition: Instruction.h:42
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Fetch the type representing an 8-bit integer.
Definition: IRBuilder.h:502
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Definition: MachineSSAContext.h:30
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void copyAttributesFrom(const Function *Src)
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Definition: Function.cpp:715
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Change the name of the value.
Definition: Value.cpp:375
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static UndefValue * get(Type *T)
Static factory methods - Return an 'undef' object of the specified type.
Definition: Constants.cpp:1713
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Definition: Alignment.h:39
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CallingConv::ID getCallingConv() const
Definition: InstrTypes.h:1455
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bool use_empty() const
Definition: Value.h:344
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Function * getCaller()
Helper to get the caller (the parent function).
Definition: Instructions.cpp:285
CFG.h
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Invoke instruction.
Definition: Instructions.h:3809
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void sort(IteratorTy Start, IteratorTy End)
Definition: STLExtras.h:1682
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Definition: IRBuilder.h:1991
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An instruction for storing to memory.
Definition: Instructions.h:298
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AttributeSet getRetAttrs() const
The attributes for the ret value are returned.
Definition: Attributes.cpp:1465
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SymbolTableList< Instruction >::iterator eraseFromParent()
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Definition: Instruction.cpp:81
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Definition: AssumptionCache.h:173
llvm::PreservedAnalyses::preserve
void preserve()
Mark an analysis as preserved.
Definition: PassManager.h:173
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void copyMetadata(const GlobalObject *Src, unsigned Offset)
Copy metadata from Src, adjusting offsets by Offset.
Definition: Metadata.cpp:1551
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compiles ldr LCPI1_0 ldr ldr mov lsr tst moveq r1 ldr LCPI1_1 and r0 bx lr It would be better to do something like to fold the shift into the conditional move
Definition: README.txt:546
PromoteMemToReg.h
MemoryLocation.h
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Definition: DenseMap.h:714
llvm::AAResults::canInstructionRangeModRef
bool canInstructionRangeModRef(const Instruction &I1, const Instruction &I2, const MemoryLocation &Loc, const ModRefInfo Mode)
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Definition: AliasAnalysis.cpp:714
I
#define I(x, y, z)
Definition: MD5.cpp:58
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Definition: ArgumentPromotion.cpp:98
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PointerType * getInt8PtrTy(unsigned AddrSpace=0)
Fetch the type representing a pointer to an 8-bit integer value.
Definition: IRBuilder.h:560
llvm::IRBuilderBase::getInt
ConstantInt * getInt(const APInt &AI)
Get a constant integer value.
Definition: IRBuilder.h:488
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static Function * Create(FunctionType *Ty, LinkageTypes Linkage, unsigned AddrSpace, const Twine &N="", Module *M=nullptr)
Definition: Function.h:137
IRBuilder.h
assert
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
Ptr
@ Ptr
Definition: TargetLibraryInfo.cpp:60
areTypesABICompatible
static bool areTypesABICompatible(ArrayRef< Type * > Types, const Function &F, const TargetTransformInfo &TTI)
Check if callers and callee agree on how promoted arguments would be passed.
Definition: ArgumentPromotion.cpp:688
llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, 4, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::empty
bool empty() const
Definition: DenseMap.h:98
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Return the iterator pointing to the end of the argument list.
Definition: InstrTypes.h:1322
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A node in the call graph.
Definition: LazyCallGraph.h:315
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Class for arbitrary precision integers.
Definition: APInt.h:75
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Definition: DepthFirstIterator.h:70
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ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: APInt.h:32
DataLayout.h
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#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
Definition: ErrorHandling.h:143
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Represents analyses that only rely on functions' control flow.
Definition: PassManager.h:113
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const Function * getFunction() const
Return the function this instruction belongs to.
Definition: Instruction.cpp:73
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void replaceAllUsesWith(Value *V)
Change all uses of this to point to a new Value.
Definition: Value.cpp:532
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void append_range(Container &C, Range &&R)
Wrapper function to append a range to a container.
Definition: STLExtras.h:2013
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@ Mod
The access may modify the value stored in memory.
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Common base class shared among various IRBuilders.
Definition: IRBuilder.h:94
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Definition: AArch64SLSHardening.cpp:76
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Determine that this argument is safe to promote, and find the argument parts it can be promoted into.
Definition: ArgumentPromotion.cpp:448
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void updateMinLegalVectorWidthAttr(Function &Fn, uint64_t Width)
Update min-legal-vector-width if it is in Attribute and less than Width.
Definition: Attributes.cpp:2153
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Return a constant reference to the value's name.
Definition: Value.cpp:308
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An instruction for reading from memory.
Definition: Instructions.h:174
llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, 4, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::insert
std::pair< iterator, bool > insert(const std::pair< KeyT, ValueT > &KV)
Definition: DenseMap.h:207
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iterator begin()
Definition: Function.h:707
llvm::make_scope_exit
detail::scope_exit< std::decay_t< Callable > > make_scope_exit(Callable &&F)
Definition: ScopeExit.h:59
Argument.h
Callee
amdgpu Simplify well known AMD library false FunctionCallee Callee
Definition: AMDGPULibCalls.cpp:187
Attributes.h
llvm::CGSCCUpdateResult
Support structure for SCC passes to communicate updates the call graph back to the CGSCC pass manager...
Definition: CGSCCPassManager.h:232
llvm::Twine
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:81
llvm::PreservedAnalyses::all
static PreservedAnalyses all()
Construct a special preserved set that preserves all passes.
Definition: PassManager.h:158
llvm::isGuaranteedToTransferExecutionToSuccessor
bool isGuaranteedToTransferExecutionToSuccessor(const Instruction *I)
Return true if this function can prove that the instruction I will always transfer execution to one o...
Definition: ValueTracking.cpp:5493
llvm::TypeSize
Definition: TypeSize.h:435
Casting.h
llvm::Instruction::setAAMetadata
void setAAMetadata(const AAMDNodes &N)
Sets the AA metadata on this instruction from the AAMDNodes structure.
Definition: Metadata.cpp:1514
llvm::GetElementPtrInst::getTypeAtIndex
static Type * getTypeAtIndex(Type *Ty, Value *Idx)
Return the type of the element at the given index of an indexable type.
Definition: Instructions.cpp:1848
Function.h
llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, 4, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::size
unsigned size() const
Definition: DenseMap.h:99
PassManager.h
llvm::Type::getPointerTo
PointerType * getPointerTo(unsigned AddrSpace=0) const
Return a pointer to the current type.
Definition: Type.cpp:774
llvm::SmallVectorImpl::clear
void clear()
Definition: SmallVector.h:614
llvm::Function::arg_begin
arg_iterator arg_begin()
Definition: Function.h:722
llvm::AllocaInst::setAlignment
void setAlignment(Align Align)
Definition: Instructions.h:126
CallGraph.h
llvm::DominatorTreeAnalysis
Analysis pass which computes a DominatorTree.
Definition: Dominators.h:271
Instructions.h
llvm::PreservedAnalyses::preserveSet
void preserveSet()
Mark an analysis set as preserved.
Definition: PassManager.h:188
llvm::AttributeSet
Definition: Attributes.h:295
SmallVector.h
User.h
Dominators.h
N
#define N
llvm::DenseMapBase< SmallDenseMap< KeyT, ValueT, 4, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::try_emplace
std::pair< iterator, bool > try_emplace(KeyT &&Key, Ts &&... Args)
Definition: DenseMap.h:222
llvm::SmallVectorImpl::pop_back_val
T pop_back_val()
Definition: SmallVector.h:677
TargetTransformInfo.h
llvm::AAResults::canBasicBlockModify
bool canBasicBlockModify(const BasicBlock &BB, const MemoryLocation &Loc)
Check if it is possible for execution of the specified basic block to modify the location Loc.
Definition: AliasAnalysis.cpp:704
ScopeExit.h
llvm::SmallVectorImpl
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: APFloat.h:42
llvm::CallBase
Base class for all callable instructions (InvokeInst and CallInst) Holds everything related to callin...
Definition: InstrTypes.h:1174
DerivedTypes.h
llvm::AnalysisManager
A container for analyses that lazily runs them and caches their results.
Definition: InstructionSimplify.h:42
BB
Common register allocation spilling lr str ldr sxth r3 ldr mla r4 can lr mov lr str ldr sxth r3 mla r4 and then merge mul and lr str ldr sxth r3 mla r4 It also increase the likelihood the store may become dead bb27 Successors according to LLVM BB
Definition: README.txt:39
GEP
Hexagon Common GEP
Definition: HexagonCommonGEP.cpp:171
llvm::Value::takeName
void takeName(Value *V)
Transfer the name from V to this value.
Definition: Value.cpp:381
llvm::AMDGPU::HSAMD::Kernel::Key::Args
constexpr char Args[]
Key for Kernel::Metadata::mArgs.
Definition: AMDGPUMetadata.h:394
llvm::AllocaInst
an instruction to allocate memory on the stack
Definition: Instructions.h:59
llvm::inverse_depth_first_ext
iterator_range< idf_ext_iterator< T, SetTy > > inverse_depth_first_ext(const T &G, SetTy &S)
Definition: DepthFirstIterator.h:303
llvm::LazyCallGraph
A lazily constructed view of the call graph of a module.
Definition: LazyCallGraph.h:110
raw_ostream.h
llvm::StoreInst::getPointerOperandIndex
static unsigned getPointerOperandIndex()
Definition: Instructions.h:392
llvm::AttributeList::getParamAttrs
AttributeSet getParamAttrs(unsigned ArgNo) const
The attributes for the argument or parameter at the given index are returned.
Definition: Attributes.cpp:1461
llvm::FunctionAnalysisManagerCGSCCProxy
A proxy from a FunctionAnalysisManager to an SCC.
Definition: CGSCCPassManager.h:392
allCallersPassValidPointerForArgument
static bool allCallersPassValidPointerForArgument(Argument *Arg, Align NeededAlign, uint64_t NeededDerefBytes)
Return true if we can prove that all callees pass in a valid pointer for the specified function argum...
Definition: ArgumentPromotion.cpp:426
Value.h
llvm::Function::setAttributes
void setAttributes(AttributeList Attrs)
Set the attribute list for this Function.
Definition: Function.h:317
llvm::FunctionType::getReturnType
Type * getReturnType() const
Definition: DerivedTypes.h:124
llvm::Value
LLVM Value Representation.
Definition: Value.h:74
Debug.h
llvm::Value::users
iterator_range< user_iterator > users()
Definition: Value.h:421
llvm::isAllocaPromotable
bool isAllocaPromotable(const AllocaInst *AI)
Return true if this alloca is legal for promotion.
Definition: PromoteMemoryToRegister.cpp:63
llvm::MemoryLocation
Representation for a specific memory location.
Definition: MemoryLocation.h:211
llvm::isDereferenceableAndAlignedPointer
bool isDereferenceableAndAlignedPointer(const Value *V, Type *Ty, Align Alignment, const DataLayout &DL, const Instruction *CtxI=nullptr, AssumptionCache *AC=nullptr, const DominatorTree *DT=nullptr, const TargetLibraryInfo *TLI=nullptr)
Returns true if V is always a dereferenceable pointer with alignment greater or equal than requested.
Definition: Loads.cpp:201
llvm::CallBase::setCallingConv
void setCallingConv(CallingConv::ID CC)
Definition: InstrTypes.h:1459
llvm::FunctionType
Class to represent function types.
Definition: DerivedTypes.h:103
llvm::Use
A Use represents the edge between a Value definition and its users.
Definition: Use.h:43
llvm::SmallPtrSetImpl::insert
std::pair< iterator, bool > insert(PtrType Ptr)
Inserts Ptr if and only if there is no element in the container equal to Ptr.
Definition: SmallPtrSet.h:365
llvm::PoisonValue::get
static PoisonValue * get(Type *T)
Static factory methods - Return an 'poison' object of the specified type.
Definition: Constants.cpp:1732