[llvm] check if operand is div in fold FDivSqrtDivisor (PR #81970)

[Matt Arsenault via llvm-commits]

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@@ -173,3 +173,20 @@ entry:
   ret double %div1
 }
 
+; Function Attrs: nounwind ssp uwtable(sync)
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arsenm wrote:

```suggestion
```

https://github.com/llvm/llvm-project/pull/81970