[PATCH] D106191: [clang] Option control afn flag

[Bardia Mahjour via Phabricator via cfe-commits]

bmahjour added inline comments.


================
Comment at: clang/include/clang/Driver/Options.td:1732-1733
   NegFlag<SetFalse>>;
-def fapprox_func : Flag<["-"], "fapprox-func">, Group<f_Group>, Flags<[CC1Option, NoDriverOption]>,
-  MarshallingInfoFlag<LangOpts<"ApproxFunc">>, ImpliedByAnyOf<[menable_unsafe_fp_math.KeyPath]>;
 defm finite_math_only : BoolFOption<"finite-math-only",
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So this option already exists and seems to behave the way we want it to. Does anyone know why it was made `NoDriverOption`?

```
> cat fp.c
#include <math.h>
void foo(float *f1, float *f2)
{
  *f1 = sin(*f2) + *f1;
}
> clang -c fp.c -S -emit-llvm -mllvm -disable-llvm-optzns -O3 -Xclang -fapprox-func && grep afn fp.ll
  %call = call afn double @sin(double %conv) #2
  %add = fadd afn double %call, %conv1
```

Could we just expose it as a supported option and call it done. ie make it more like `fhonor_nans` below but without introducing a new function attribute:

```def fapprox_func : Flag<["-"], "fapprox-func">, Group<f_Group>;```

so that instead of having `-Xclang -fapprox-func ` in the command above we could just have `-fapprox-func `?


================
Comment at: clang/test/CodeGen/afn-flag-test.c:10
+  // CHECK-AFN:      %{{.*}} = call afn double @{{.*}}exp{{.*}}(double %{{.*}})
+  // CHECK-AFN:      attributes #0 ={{.*}} "approx-func-fp-math"="true" {{.*}}
+
----------------
can we avoid these attributes?


================
Comment at: clang/test/CodeGen/afn-flag-test.c:13
+  // CHECK-NO-AFN:   %{{.*}} = call double @{{.*}}exp{{.*}}(double %{{.*}})
+  // CHECK-NO-AFN-NOT:  attributes #0 ={{.*}} "approx-func-fp-math"="true" {{.*}}
+}
----------------
avoid attributes.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D106191/new/

https://reviews.llvm.org/D106191