[llvm] [IRBuilder] Refactor FMF interface (PR #121657)

[Nikita Popov via llvm-commits]

================
@@ -425,11 +425,9 @@ static bool foldSqrt(CallInst *Call, LibFunc Func, TargetTransformInfo &TTI,
            Arg, 0,
            SimplifyQuery(Call->getDataLayout(), &TLI, &DT, &AC, Call)))) {
     IRBuilder<> Builder(Call);
-    IRBuilderBase::FastMathFlagGuard Guard(Builder);
-    Builder.setFastMathFlags(Call->getFastMathFlags());
-
-    Value *NewSqrt = Builder.CreateIntrinsic(Intrinsic::sqrt, Ty, Arg,
-                                             /*FMFSource=*/nullptr, "sqrt");
+    Value *NewSqrt =
+        Builder.CreateIntrinsic(Intrinsic::sqrt, Ty, Arg,
+                                /*FMFSource=*/Call->getFastMathFlags(), "sqrt");
----------------
nikic wrote:

```suggestion
                                Call->getFastMathFlags(), "sqrt");
```

https://github.com/llvm/llvm-project/pull/121657