[llvm] [AllocToken] Merge !alloc_token metadata across optimization passes (PR #211516)

[Marco Elver via llvm-commits]

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@@ -1332,6 +1333,43 @@ MDNode *MDNode::getMergedCalleeTypeMetadata(const MDNode *A, const MDNode *B) {
   return MDNode::get(A->getContext(), AB);
 }
 
+MDNode *MDNode::getMergedAllocTokenMetadata(const MDNode *A, const MDNode *B) {
+  if (!A || !B)
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melver wrote:

I added a comment.

https://github.com/llvm/llvm-project/pull/211516