[llvm] [InstCombine] Fold select pattern with sub and negation to abs intrinsic (PR #156246)

via llvm-commits llvm-commits at lists.llvm.org
Sun Aug 31 07:11:57 PDT 2025


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

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``````````diff
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index d75e34f90..794db87be 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1157,9 +1157,9 @@ static Value *foldAbsDiff(ICmpInst *Cmp, Value *TVal, Value *FVal,
   // Recognize the pattern where we have sub, icmp, neg(sub), select
   if (Pred == CmpInst::ICMP_SGT &&
       match(TI, m_Sub(m_Specific(A), m_Specific(B))) &&
-      match(FI, m_Neg(m_Specific(TI))) &&
-      TI->hasNoSignedWrap()) {
-    return Builder.CreateBinaryIntrinsic(Intrinsic::abs, TI, Builder.getFalse());
+      match(FI, m_Neg(m_Specific(TI))) && TI->hasNoSignedWrap()) {
+    return Builder.CreateBinaryIntrinsic(Intrinsic::abs, TI,
+                                         Builder.getFalse());
   }
 
   return nullptr;

``````````

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https://github.com/llvm/llvm-project/pull/156246


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