[llvm] [ConstraintElim] Check the other signedness when hasSameSign (PR #128168)

[Yingwei Zheng 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())
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dtcxzyw wrote:

Is it necessary to handle eq/ne predicates? We have added eq/ne facts into both constraint systems in https://github.com/llvm/llvm-project/pull/121423. Can you add some tests to demonstrate its necessity?



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