[llvm] [SCEV] Generalize A + zext(-A + B) fold to A + zext(C + X) (PR #209160)

via llvm-commits llvm-commits at lists.llvm.org
Mon Jul 13 05:28:05 PDT 2026


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git-clang-format --diff origin/main HEAD --extensions cpp -- llvm/lib/Analysis/ScalarEvolution.cpp --diff_from_common_commit
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``````````diff
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index c3b2693fe..25bea2180 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -2825,12 +2825,11 @@ const SCEV *ScalarEvolution::getAddExpr(SmallVectorImpl<SCEVUse> &Ops,
           // NUW on `(-C) + (C + X) = X` proves that `C + X` did not wrap
           // below zero, so `zext(C + X) == sext(C) + zext(X)`.
           hasFlags(StrengthenNoWrapFlags(this, scAddExpr,
-                                        {getConstant(-*C), Add},
-                                        SCEV::FlagAnyWrap),
-                  SCEV::FlagNUW)) {
-        return getAddExpr(
-            A, getSignExtendExpr(getConstant(*C), B->getType()),
-            getZeroExtendExpr(X, B->getType()));
+                                         {getConstant(-*C), Add},
+                                         SCEV::FlagAnyWrap),
+                   SCEV::FlagNUW)) {
+        return getAddExpr(A, getSignExtendExpr(getConstant(*C), B->getType()),
+                          getZeroExtendExpr(X, B->getType()));
       }
     }
   }

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https://github.com/llvm/llvm-project/pull/209160


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