[llvm] [InstCombine] Fold redundant select guards for ctpop (PR #195443)

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Sat May 2 04:42:26 PDT 2026


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``````````bash
git-clang-format --diff origin/main HEAD --extensions cpp -- llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp --diff_from_common_commit
``````````

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View the diff from clang-format here.
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``````````diff
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index c87d9bfa8..59c3ebef7 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -4400,7 +4400,8 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
     Value *CtpopCmpLHS, *CtpopCmpRHS;
     unsigned CtpopBitWidth = SelType->getScalarSizeInBits();
     if (match(FalseVal, m_Intrinsic<Intrinsic::ctpop>(m_Value(X))) &&
-        match(CondVal, m_ICmp(CtpopPred, m_Value(CtpopCmpLHS), m_Value(CtpopCmpRHS)))) {
+        match(CondVal,
+              m_ICmp(CtpopPred, m_Value(CtpopCmpLHS), m_Value(CtpopCmpRHS)))) {
       if (CtpopCmpLHS == X && CtpopPred == ICmpInst::ICMP_ULT &&
           match(CtpopCmpRHS, m_SpecificInt(2)) && TrueVal == X)
         return replaceInstUsesWith(SI, FalseVal);

``````````

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https://github.com/llvm/llvm-project/pull/195443


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