[llvm] [IR] Handle fabs LHS in `fcmpImpliesClass` (PR #152913)

[Yingwei Zheng via llvm-commits]

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@@ -151,26 +151,40 @@ template <typename ContextT> class GenericFloatingPointPredicateUtils {
       case FCmpInst::FCMP_UNO:
         return exactClass(Src, fcNan);
       case FCmpInst::FCMP_OGT: // x > 0
+        if (IsFabs)
+          return exactClass(Src, fcSubnormal | fcNormal | fcInf);
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dtcxzyw wrote:

It would be simpler to add a helper and use `inverse_fabs`.

https://github.com/llvm/llvm-project/pull/152913