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[Transforms] move copying of load metadata to helper function; NFC 

There's another proposed load combine that can make use of this code
in D64432.

llvm-svn: 366949
This commit is contained in:
Sanjay Patel 2019-07-24 22:11:11 +00:00
parent 87186b2447
commit 86e9f9dc26
3 changed files with 56 additions and 45 deletions
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4
llvm/include/llvm/Transforms/Utils/Local.h
View File

@ -427,6 +427,10 @@ void combineMetadata(Instruction *K, const Instruction *J,
void combineMetadataForCSE(Instruction *K, const Instruction *J,
bool DoesKMove);
/// Copy the metadata from the source instruction to the destination (the
/// replacement for the source instruction).
void copyMetadataForLoad(LoadInst &Dest, const LoadInst &Source);
/// Patch the replacement so that it is not more restrictive than the value
/// being replaced. It assumes that the replacement does not get moved from
/// its original position.

46
llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
View File

@ -455,9 +455,6 @@ static LoadInst *combineLoadToNewType(InstCombiner &IC, LoadInst &LI, Type *NewT
Value *Ptr = LI.getPointerOperand();
unsigned AS = LI.getPointerAddressSpace();
SmallVector<std::pair<unsigned, MDNode *>, 8> MD;
LI.getAllMetadata(MD);
Value *NewPtr = nullptr;
if (!(match(Ptr, m_BitCast(m_Value(NewPtr))) &&
NewPtr->getType()->getPointerElementType() == NewTy &&
@ -467,48 +464,7 @@ static LoadInst *combineLoadToNewType(InstCombiner &IC, LoadInst &LI, Type *NewT
LoadInst *NewLoad = IC.Builder.CreateAlignedLoad(
NewTy, NewPtr, LI.getAlignment(), LI.isVolatile(), LI.getName() + Suffix);
NewLoad->setAtomic(LI.getOrdering(), LI.getSyncScopeID());
MDBuilder MDB(NewLoad->getContext());
for (const auto &MDPair : MD) {
unsigned ID = MDPair.first;
MDNode *N = MDPair.second;
// Note, essentially every kind of metadata should be preserved here! This
// routine is supposed to clone a load instruction changing *only its type*.
// The only metadata it makes sense to drop is metadata which is invalidated
// when the pointer type changes. This should essentially never be the case
// in LLVM, but we explicitly switch over only known metadata to be
// conservatively correct. If you are adding metadata to LLVM which pertains
// to loads, you almost certainly want to add it here.
switch (ID) {
case LLVMContext::MD_dbg:
case LLVMContext::MD_tbaa:
case LLVMContext::MD_prof:
case LLVMContext::MD_fpmath:
case LLVMContext::MD_tbaa_struct:
case LLVMContext::MD_invariant_load:
case LLVMContext::MD_alias_scope:
case LLVMContext::MD_noalias:
case LLVMContext::MD_nontemporal:
case LLVMContext::MD_mem_parallel_loop_access:
case LLVMContext::MD_access_group:
// All of these directly apply.
NewLoad->setMetadata(ID, N);
break;
case LLVMContext::MD_nonnull:
copyNonnullMetadata(LI, N, *NewLoad);
break;
case LLVMContext::MD_align:
case LLVMContext::MD_dereferenceable:
case LLVMContext::MD_dereferenceable_or_null:
// These only directly apply if the new type is also a pointer.
if (NewTy->isPointerTy())
NewLoad->setMetadata(ID, N);
break;
case LLVMContext::MD_range:
copyRangeMetadata(IC.getDataLayout(), LI, N, *NewLoad);
break;
}
}
copyMetadataForLoad(*NewLoad, LI);
return NewLoad;
}

51
llvm/lib/Transforms/Utils/Local.cpp
View File

@ -2390,6 +2390,57 @@ void llvm::combineMetadataForCSE(Instruction *K, const Instruction *J,
combineMetadata(K, J, KnownIDs, KDominatesJ);
}
void llvm::copyMetadataForLoad(LoadInst &Dest, const LoadInst &Source) {
SmallVector<std::pair<unsigned, MDNode *>, 8> MD;
Source.getAllMetadata(MD);
MDBuilder MDB(Dest.getContext());
Type *NewType = Dest.getType();
const DataLayout &DL = Source.getModule()->getDataLayout();
for (const auto &MDPair : MD) {
unsigned ID = MDPair.first;
MDNode *N = MDPair.second;
// Note, essentially every kind of metadata should be preserved here! This
// routine is supposed to clone a load instruction changing *only its type*.
// The only metadata it makes sense to drop is metadata which is invalidated
// when the pointer type changes. This should essentially never be the case
// in LLVM, but we explicitly switch over only known metadata to be
// conservatively correct. If you are adding metadata to LLVM which pertains
// to loads, you almost certainly want to add it here.
switch (ID) {
case LLVMContext::MD_dbg:
case LLVMContext::MD_tbaa:
case LLVMContext::MD_prof:
case LLVMContext::MD_fpmath:
case LLVMContext::MD_tbaa_struct:
case LLVMContext::MD_invariant_load:
case LLVMContext::MD_alias_scope:
case LLVMContext::MD_noalias:
case LLVMContext::MD_nontemporal:
case LLVMContext::MD_mem_parallel_loop_access:
case LLVMContext::MD_access_group:
// All of these directly apply.
Dest.setMetadata(ID, N);
break;
case LLVMContext::MD_nonnull:
copyNonnullMetadata(Source, N, Dest);
break;
case LLVMContext::MD_align:
case LLVMContext::MD_dereferenceable:
case LLVMContext::MD_dereferenceable_or_null:
// These only directly apply if the new type is also a pointer.
if (NewType->isPointerTy())
Dest.setMetadata(ID, N);
break;
case LLVMContext::MD_range:
copyRangeMetadata(DL, Source, N, Dest);
break;
}
}
}
void llvm::patchReplacementInstruction(Instruction *I, Value *Repl) {
auto *ReplInst = dyn_cast<Instruction>(Repl);
if (!ReplInst)