[llvm] fe3e9c2 - [Analysis] Avoid repeated hash lookups (NFC) (#133045)

[via llvm-commits]

Author: Kazu Hirata
Date: 2025-03-31T23:17:44-07:00
New Revision: fe3e9c2b46504e7b197245b3946abfec563e77d4

URL: https://github.com/llvm/llvm-project/commit/fe3e9c2b46504e7b197245b3946abfec563e77d4
DIFF: https://github.com/llvm/llvm-project/commit/fe3e9c2b46504e7b197245b3946abfec563e77d4.diff

LOG: [Analysis] Avoid repeated hash lookups (NFC) (#133045)

Added: 
    

Modified: 
    llvm/lib/Analysis/ScalarEvolution.cpp

Removed: 
    


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diff  --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 361206719287a..14f9a1bec8939 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -15440,9 +15440,9 @@ void ScalarEvolution::LoopGuards::collectFromBlock(
       // Bail out, unless we have a non-wrapping, monotonic range.
       if (ExactRegion.isWrappedSet() || ExactRegion.isFullSet())
         return false;
-      auto I = RewriteMap.find(LHSUnknown);
-      const SCEV *RewrittenLHS = I != RewriteMap.end() ? I->second : LHSUnknown;
-      RewriteMap[LHSUnknown] = SE.getUMaxExpr(
+      auto [I, Inserted] = RewriteMap.try_emplace(LHSUnknown);
+      const SCEV *RewrittenLHS = Inserted ? LHSUnknown : I->second;
+      I->second = SE.getUMaxExpr(
           SE.getConstant(ExactRegion.getUnsignedMin()),
           SE.getUMinExpr(RewrittenLHS,
                          SE.getConstant(ExactRegion.getUnsignedMax())));