[llvm-branch-commits] [llvm] [ir] MD_prof is not UB-implying (PR #152420)

[Mircea Trofin via llvm-branch-commits]

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@@ -1678,6 +1680,8 @@ void Instruction::dropUnknownNonDebugMetadata(ArrayRef<unsigned> KnownIDs) {
 
   // A DIAssignID attachment is debug metadata, don't drop it.
   KnownSet.insert(LLVMContext::MD_DIAssignID);
+  if (!ProfcheckDisableMetadataFixes)
+    KnownSet.insert(LLVMContext::MD_prof);
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mtrofin wrote:

I also have mixed feelings about this, I got worried we may accidentally keep the wrong profile info (meaning, uses should reason about what the right info is) - I'm curious what your reasoning was?

https://github.com/llvm/llvm-project/pull/152420