[llvm] [InstCombine] Treat `uitofp nneg` as non-negative signed range for fcmp clamp folds (PR #208234)

[via llvm-commits]

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@@ -8408,6 +8412,48 @@ Instruction *InstCombinerImpl::foldFCmpIntToFPConst(FCmpInst &I,
     }
   }
 
+  Value *X = LHSI->getOperand(0);
+  bool IsNonNegUIToFP =
+      LHSUnsigned && cast<PossiblyNonNegInst>(LHSI)->hasNonNeg();
+  if (IsNonNegUIToFP && IsExact) {
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imkiva wrote:

Opened #209097

https://github.com/llvm/llvm-project/pull/208234