[llvm] [ConstraintElim] Teach checkAndReplaceCondition about samesign (PR #128168)

[Florian Hahn via llvm-commits]

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@@ -1460,6 +1460,13 @@ static bool checkAndReplaceCondition(
           checkCondition(Cmp->getPredicate(), Cmp->getOperand(0),
                          Cmp->getOperand(1), Cmp, Info))
     return ReplaceCmpWithConstant(Cmp, *ImpliedCondition);
+
+  if (Cmp->hasSameSign() && Cmp->isUnsigned())
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fhahn wrote:

Might be good to add a brief comment here that we also try the signed predicate for samesign unsigned predicates.

https://github.com/llvm/llvm-project/pull/128168