[canonicalization] Refactor how we create new stores into a helper

function. This is a bit tidier anyways and will make a subsquent patch
simpler as I want to add another case to this combine.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226746 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth 2015-01-21 23:45:01 +00:00
parent 3f6acdd265
commit 7e57686e51

View File

@ -489,6 +489,53 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
return nullptr;
}
/// \brief Combine a store to a new type.
///
/// Returns the newly created store instruction.
static StoreInst *combineStoreToNewValue(InstCombiner &IC, StoreInst &SI, Value *V) {
Value *Ptr = SI.getPointerOperand();
unsigned AS = SI.getPointerAddressSpace();
SmallVector<std::pair<unsigned, MDNode *>, 8> MD;
SI.getAllMetadata(MD);
StoreInst *NewStore = IC.Builder->CreateAlignedStore(
V, IC.Builder->CreateBitCast(Ptr, V->getType()->getPointerTo(AS)),
SI.getAlignment());
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 store 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 stores, 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_alias_scope:
case LLVMContext::MD_noalias:
case LLVMContext::MD_nontemporal:
case LLVMContext::MD_mem_parallel_loop_access:
case LLVMContext::MD_nonnull:
// All of these directly apply.
NewStore->setMetadata(ID, N);
break;
case LLVMContext::MD_invariant_load:
case LLVMContext::MD_range:
break;
}
}
return NewStore;
}
/// \brief Combine stores to match the type of value being stored.
///
/// The core idea here is that the memory does not have any intrinsic type and
@ -515,49 +562,12 @@ static bool combineStoreToValueType(InstCombiner &IC, StoreInst &SI) {
if (!SI.isSimple())
return false;
Value *Ptr = SI.getPointerOperand();
Value *V = SI.getValueOperand();
unsigned AS = SI.getPointerAddressSpace();
SmallVector<std::pair<unsigned, MDNode *>, 8> MD;
SI.getAllMetadata(MD);
// Fold away bit casts of the stored value by storing the original type.
if (auto *BC = dyn_cast<BitCastInst>(V)) {
V = BC->getOperand(0);
StoreInst *NewStore = IC.Builder->CreateAlignedStore(
V, IC.Builder->CreateBitCast(Ptr, V->getType()->getPointerTo(AS)),
SI.getAlignment());
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 store 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 stores, 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_alias_scope:
case LLVMContext::MD_noalias:
case LLVMContext::MD_nontemporal:
case LLVMContext::MD_mem_parallel_loop_access:
case LLVMContext::MD_nonnull:
// All of these directly apply.
NewStore->setMetadata(ID, N);
break;
case LLVMContext::MD_invariant_load:
case LLVMContext::MD_range:
break;
}
}
combineStoreToNewValue(IC, SI, V);
return true;
}