[llvm] [ThinLTO] optimize propagateAttributes performance (PR #132917)

[Teresa Johnson via llvm-commits]

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@@ -213,9 +211,10 @@ propagateAttributesToRefs(GlobalValueSummary *S,
   for (auto &VI : S->refs()) {
     assert(VI.getAccessSpecifier() == 0 || isa<FunctionSummary>(S));
     if (!VI.getAccessSpecifier()) {
-      if (!MarkedNonReadWriteOnly.insert(VI).second)
+      if (VI.getRef()->second.MarkedNonReadWriteOnly)
         continue;
-    } else if (MarkedNonReadWriteOnly.contains(VI))
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teresajohnson wrote:

I think this check might be useless and possibly can be removed. We only get here and do the else if check if getAccessSpecifier() is non-zero, which means the VI is still either read or write only. But we only add a VI to the MarkedNonReadWriteOnly set if its getAccessSpecifier() is 0, and we only ever go towards 0 (marking things not read or write only), never the reverse.

https://github.com/llvm/llvm-project/pull/132917