[llvm] [JumpThreading][GVN] Copy metadata when inserting preload into preds (PR #134403)

[Yingwei Zheng via llvm-commits]

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@@ -1516,26 +1516,24 @@ void GVNPass::eliminatePartiallyRedundantLoad(
         MSSAU->insertUse(cast<MemoryUse>(NewAccess), /*RenameUses=*/true);
     }
 
-    // Transfer the old load's AA tags to the new load.
-    AAMDNodes Tags = Load->getAAMetadata();
-    if (Tags)
-      NewLoad->setAAMetadata(Tags);
-
-    if (auto *MD = Load->getMetadata(LLVMContext::MD_invariant_load))
-      NewLoad->setMetadata(LLVMContext::MD_invariant_load, MD);
-    if (auto *InvGroupMD = Load->getMetadata(LLVMContext::MD_invariant_group))
-      NewLoad->setMetadata(LLVMContext::MD_invariant_group, InvGroupMD);
-    if (auto *RangeMD = Load->getMetadata(LLVMContext::MD_range))
-      NewLoad->setMetadata(LLVMContext::MD_range, RangeMD);
-    if (auto *AccessMD = Load->getMetadata(LLVMContext::MD_access_group))
-      if (LI->getLoopFor(Load->getParent()) == LI->getLoopFor(UnavailableBlock))
-        NewLoad->setMetadata(LLVMContext::MD_access_group, AccessMD);
-
-    // We do not propagate the old load's debug location, because the new
-    // load now lives in a different BB, and we want to avoid a jumpy line
-    // table.
-    // FIXME: How do we retain source locations without causing poor debugging
-    // behavior?
+    NewLoad->copyMetadata(*Load);
+    std::optional<bool> TransfersExecution = std::nullopt;
+    NewLoad->eraseMetadataIf([&](unsigned Kind, const MDNode *MD) {
+      if (Kind == LLVMContext::MD_dbg || Kind == LLVMContext::MD_annotation)
+        return false;
+      if (is_contained(Metadata::PoisonGeneratingIDs, Kind))
+        return false;
+      // Try to salvage UB-implying metadata if we know it is guaranteed to
+      // transfer the execution to the original load.
+      if (!TransfersExecution.has_value()) {
+        // TEST ONLY
+        assert(
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dtcxzyw wrote:

I am not sure if it holds for GVN.



https://github.com/llvm/llvm-project/pull/134403