[llvm-branch-commits] [llvm] PeepholeOpt: Avoid double map lookup (PR #124531)

[Jay Foad via llvm-branch-commits]

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@@ -1035,8 +1035,10 @@ bool PeepholeOptimizer::findNextSource(RegSubRegPair RegSubReg,
         return false;
 
       // Insert the Def -> Use entry for the recently found source.
-      ValueTrackerResult CurSrcRes = RewriteMap.lookup(CurSrcPair);
-      if (CurSrcRes.isValid()) {
+      auto [InsertPt, WasInserted] = RewriteMap.try_emplace(CurSrcPair, Res);
+
+      ValueTrackerResult CurSrcRes = InsertPt->second;
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jayfoad wrote:

Sink this inside the "if"

https://github.com/llvm/llvm-project/pull/124531