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NewGVN: Apply the fast math flags fix in r267113 to NewGVN as well.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@294922 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Daniel Berlin 2017-02-12 22:25:20 +00:00
parent 8697d189a9
commit c4bc95816e
2 changed files with 24 additions and 22 deletions
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45
lib/Transforms/Scalar/NewGVN.cpp
View File

@ -2059,31 +2059,34 @@ void NewGVN::convertDenseToLoadsAndStores(
}
static void patchReplacementInstruction(Instruction *I, Value *Repl) {
auto *ReplInst = dyn_cast<Instruction>(Repl);
if (!ReplInst)
return;
// Patch the replacement so that it is not more restrictive than the value
// being replaced.
auto *Op = dyn_cast<BinaryOperator>(I);
auto *ReplOp = dyn_cast<BinaryOperator>(Repl);
// Note that if 'I' is a load being replaced by some operation,
// for example, by an arithmetic operation, then andIRFlags()
// would just erase all math flags from the original arithmetic
// operation, which is clearly not wanted and not needed.
if (!isa<LoadInst>(I))
ReplInst->andIRFlags(I);
if (Op && ReplOp)
ReplOp->andIRFlags(Op);
// FIXME: If both the original and replacement value are part of the
// same control-flow region (meaning that the execution of one
// guarantees the execution of the other), then we can combine the
// noalias scopes here and do better than the general conservative
// answer used in combineMetadata().
if (auto *ReplInst = dyn_cast<Instruction>(Repl)) {
// FIXME: If both the original and replacement value are part of the
// same control-flow region (meaning that the execution of one
// guarentees the executation of the other), then we can combine the
// noalias scopes here and do better than the general conservative
// answer used in combineMetadata().
// In general, GVN unifies expressions over different control-flow
// regions, and so we need a conservative combination of the noalias
// scopes.
unsigned KnownIDs[] = {
LLVMContext::MD_tbaa, LLVMContext::MD_alias_scope,
LLVMContext::MD_noalias, LLVMContext::MD_range,
LLVMContext::MD_fpmath, LLVMContext::MD_invariant_load,
LLVMContext::MD_invariant_group};
combineMetadata(ReplInst, I, KnownIDs);
}
// In general, GVN unifies expressions over different control-flow
// regions, and so we need a conservative combination of the noalias
// scopes.
static const unsigned KnownIDs[] = {
LLVMContext::MD_tbaa, LLVMContext::MD_alias_scope,
LLVMContext::MD_noalias, LLVMContext::MD_range,
LLVMContext::MD_fpmath, LLVMContext::MD_invariant_load,
LLVMContext::MD_invariant_group};
combineMetadata(ReplInst, I, KnownIDs);
}
static void patchAndReplaceAllUsesWith(Instruction *I, Value *Repl) {

1
test/Transforms/NewGVN/flags.ll
View File

@ -1,4 +1,3 @@
; XFAIL: *
; RUN: opt -newgvn -S < %s | FileCheck %s
declare void @use(i1)