[PATCH] D12710: InstCombine: Preserve tbaa metadata when merging loads that are phi arguments

[Philip Reames via llvm-commits]

reames added a subscriber: reames.

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Comment at: lib/Transforms/InstCombine/InstCombinePHI.cpp:357
@@ +356,3 @@
+    LoadInst *LI = cast<LoadInst>(PN.getIncomingValue(i));
+    combineMetadata(FirstLI, LI, { LLVMContext::MD_tbaa });
+    Value *NewInVal = LI->getOperand(0);
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On first look, this seems like it's the wrong approach.  You're mutating the metadata on an existing load to accumulate the intersection of all of the incoming loads.  It's not clear to me that we want to be killing the metadata on the input load.  


http://reviews.llvm.org/D12710