[PATCH] D110064: [SelectionDAG] Assume that a GlobalAlias may alias other global values

Mon Sep 20 05:59:03 PDT 2021

niravd added inline comments.

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Comment at: llvm/lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp:155
+    // global values and at least one is a GlobalAlias.
+    if (IsGV0 && IsGV1 &&
+        (isa<GlobalAlias>(cast<GlobalAddressSDNode>(
----------------
It looks like we can walk the GlobalAlias to the referenced object. If so, we should fully walk to a non-alias global instead.

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Comment at: llvm/lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp:168
+    // dereferenced)?
+    if (BasePtr0.getIndex() == BasePtr1.getIndex()) {
+      IsAlias = false;
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We should handle this case earlier so we can correct determine that identical global aliases do in fact alias.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110064/new/

https://reviews.llvm.org/D110064