[X86] Avoid repeated hash lookups (NFC)

[kazutakahirata]

No description provided.

[llvmbot]

@llvm/pr-subscribers-backend-x86

Author: Kazu Hirata (kazutakahirata)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/129470.diff

1 Files Affected:

• (modified) llvm/lib/Target/X86/X86ISelLowering.cpp (+4-3)

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");
   }