[InstCombine] Preserve metadata when merging loads that are phi
arguments.
Make sure InstCombiner::FoldPHIArgLoadIntoPHI doesn't drop the following
metadata:
MD_tbaa
MD_alias_scope
MD_noalias
MD_invariant_load
MD_nonnull
MD_range
rdar://problem/17617709
Differential Revision: http://reviews.llvm.org/D12710
llvm-svn: 248419
diff --git a/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp b/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
index 460f6eb..86d5f03 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
@@ -15,6 +15,7 @@
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Transforms/Utils/Local.h"
using namespace llvm;
#define DEBUG_TYPE "instcombine"
@@ -349,24 +350,37 @@
Value *InVal = FirstLI->getOperand(0);
NewPN->addIncoming(InVal, PN.getIncomingBlock(0));
+ LoadInst *NewLI = new LoadInst(NewPN, "", isVolatile, LoadAlignment);
- // Add all operands to the new PHI.
+ unsigned KnownIDs[] = {
+ LLVMContext::MD_tbaa,
+ LLVMContext::MD_range,
+ LLVMContext::MD_invariant_load,
+ LLVMContext::MD_alias_scope,
+ LLVMContext::MD_noalias,
+ LLVMContext::MD_nonnull
+ };
+
+ for (unsigned ID : KnownIDs)
+ NewLI->setMetadata(ID, FirstLI->getMetadata(ID));
+
+ // Add all operands to the new PHI and combine TBAA metadata.
for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) {
- Value *NewInVal = cast<LoadInst>(PN.getIncomingValue(i))->getOperand(0);
+ LoadInst *LI = cast<LoadInst>(PN.getIncomingValue(i));
+ combineMetadata(NewLI, LI, KnownIDs);
+ Value *NewInVal = LI->getOperand(0);
if (NewInVal != InVal)
InVal = nullptr;
NewPN->addIncoming(NewInVal, PN.getIncomingBlock(i));
}
- Value *PhiVal;
if (InVal) {
// The new PHI unions all of the same values together. This is really
// common, so we handle it intelligently here for compile-time speed.
- PhiVal = InVal;
+ NewLI->setOperand(0, InVal);
delete NewPN;
} else {
InsertNewInstBefore(NewPN, PN);
- PhiVal = NewPN;
}
// If this was a volatile load that we are merging, make sure to loop through
@@ -376,7 +390,6 @@
for (Value *IncValue : PN.incoming_values())
cast<LoadInst>(IncValue)->setVolatile(false);
- LoadInst *NewLI = new LoadInst(PhiVal, "", isVolatile, LoadAlignment);
NewLI->setDebugLoc(FirstLI->getDebugLoc());
return NewLI;
}