[llvm] [AllocToken] Introduce sanitize_alloc_token attribute and alloc_token metadata (PR #160131)

[Nikita Popov via llvm-commits]

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@@ -3025,6 +3025,10 @@ static void combineMetadata(Instruction *K, const Instruction *J,
         // Preserve !nosanitize if both K and J have it.
         K->setMetadata(Kind, JMD);
         break;
+      case LLVMContext::MD_alloc_token:
+        // Preserve !alloc_token if both K and J have it.
+        K->setMetadata(Kind, JMD);
+        break;
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nikic wrote:

This is untested -- is this intentionally picking an arbitrary alloc_token in the case where they differ?

https://github.com/llvm/llvm-project/pull/160131