[llvm-branch-commits] [llvm] InstCombine: Handle fsub in SimplifyDemandedFPClass (PR #175852)

[Yingwei Zheng via llvm-branch-commits]

================
@@ -2157,11 +2162,13 @@ Value *InstCombinerImpl::SimplifyDemandedUseFPClass(Instruction *I,
     }
 
     // With nnan: X + {+/-}Inf --> {+/-}Inf
-    if (KnownRHS.isKnownAlways(fcInf | fcNan) &&
-        KnownLHS.isKnownNever(fcNan))
+    if (I->getOpcode() == Instruction::FAdd &&
+        KnownRHS.isKnownAlways(fcInf | fcNan) && KnownLHS.isKnownNever(fcNan)) {
----------------
dtcxzyw wrote:

```suggestion
        ResultNotNan && KnownRHS.isKnownAlways(fcInf | fcNan) && KnownLHS.isKnownNever(fcNan)) {
```

https://github.com/llvm/llvm-project/pull/175852