[llvm] [ConstraintElim] Drop invalid rows instead of failing the elimination (PR #76299)

[Florian Hahn via llvm-commits]

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@@ -96,27 +98,34 @@ bool ConstraintSystem::eliminateUsingFM() {
           IdxUpper++;
         }
 
-        if (MulOverflow(UpperV, ((-1) * LowerLast / GCD), M1))
-          return false;
+        if (MulOverflow(UpperV, ((-1) * LowerLast / GCD), M1)) {
+          Valid = false;
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fhahn wrote:

Simpler to just clear NR?

https://github.com/llvm/llvm-project/pull/76299