[llvm] [AllocToken] Add TypeFuncHash and TypeFuncHashPointerSplit modes (PR #227686)

[Ai Nozaki via llvm-commits]

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@@ -1357,35 +1357,35 @@ MDNode *MDNode::getMergedAllocTokenMetadata(const MDNode *A, const MDNode *B) {
     return nullptr;
   if (A == B)
     return const_cast<MDNode *>(A);
-  if (A->getNumOperands() != 2 || B->getNumOperands() != 2)
+  const unsigned NumOps = A->getNumOperands();
+  if ((NumOps != 2 && NumOps != 3) || B->getNumOperands() != NumOps)
     return nullptr;
   auto *CIA = mdconst::dyn_extract_or_null<ConstantInt>(A->getOperand(1));
   auto *CIB = mdconst::dyn_extract_or_null<ConstantInt>(B->getOperand(1));
   if (!CIA || !CIB)
     return nullptr;
 
-  MDString *NameA = dyn_cast<MDString>(A->getOperand(0));
-  MDString *NameB = dyn_cast<MDString>(B->getOperand(0));
-  if (!NameA || !NameB)
-    return nullptr;
-
-  if (NameA == NameB)
-    return CIA->isOne() ? const_cast<MDNode *>(A) : const_cast<MDNode *>(B);
-
+  // Join different names with '|'.
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ainozaki wrote:

Thank you for catching this. Done. I've updated `MergeNames` to preserve an empty type name when either side is unknown and added a test case. I also switched to `dyn_cast_or_null<MDString>`.

https://github.com/llvm/llvm-project/pull/227686