[llvm] 1891281 - [X86] Avoid repeated hash lookups (NFC) (#129470)

[via llvm-commits]

Author: Kazu Hirata
Date: 2025-03-03T01:04:16-08:00
New Revision: 1891281a15817996c0caada09dadc9d026331345

URL: https://github.com/llvm/llvm-project/commit/1891281a15817996c0caada09dadc9d026331345
DIFF: https://github.com/llvm/llvm-project/commit/1891281a15817996c0caada09dadc9d026331345.diff

LOG: [X86] Avoid repeated hash lookups (NFC) (#129470)

Added: 
    

Modified: 
    llvm/lib/Target/X86/X86ISelLowering.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 30e661957d774..7fb5157c00d84 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -30269,11 +30269,12 @@ static SDValue LowerShift(SDValue Op, const X86Subtarget &Subtarget,
       if (A.isUndef() || A->getAsAPIntVal().uge(EltSizeInBits))
         continue;
       unsigned CstAmt = A->getAsAPIntVal().getZExtValue();
-      if (UniqueCstAmt.count(CstAmt)) {
-        UniqueCstAmt[CstAmt].setBit(I);
+      auto [It, Inserted] = UniqueCstAmt.try_emplace(CstAmt);
+      if (!Inserted) {
+        It->second.setBit(I);
         continue;
       }
-      UniqueCstAmt[CstAmt] = APInt::getOneBitSet(NumElts, I);
+      It->second = APInt::getOneBitSet(NumElts, I);
     }
     assert(!UniqueCstAmt.empty() && "Illegal constant shift amounts");
   }