[PATCH] i386: Fix fmod/fmof/remainder/remainderf for gcc-12

[Adhemerval Zanella Netto]

On 24/11/25 11:31, Adhemerval Zanella Netto wrote:
> 
> 
> On 20/11/25 21:01, H.J. Lu wrote:
>> On Fri, Nov 21, 2025 at 7:23 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>>>
>>> On Thu, Nov 20, 2025 at 8:21 PM Adhemerval Zanella
>>> <adhemerval.zanella@linaro.org> wrote:
>>>>
>>>> The __builtin_fmod{f} and __builtin_remainder{f} were added on gcc 13,
>>>> and the minimum supported gcc is 12.  This patch adds a configure test
>>>> to check whether the compiler enables inlining for fmod/remainder, and
>>>> uses inline assembly if not.
>>>>
>>>> Checked on i686-linux-gnu wih gcc-12.
>>>> ---
>>>>  config.h.in                     |  3 +++
>>>>  sysdeps/i386/fpu/e_fmod.c       | 14 ++++++++++
>>>>  sysdeps/i386/fpu/e_fmodf.c      | 14 ++++++++++
>>>>  sysdeps/i386/fpu/e_remainder.c  | 14 ++++++++++
>>>>  sysdeps/i386/fpu/e_remainderf.c | 14 ++++++++++
>>>>  sysdeps/x86/configure           | 48 +++++++++++++++++++++++++++++++++
>>>>  sysdeps/x86/configure.ac        | 27 +++++++++++++++++++
>>>>  7 files changed, 134 insertions(+)
>>>>
>>>> diff --git a/config.h.in b/config.h.in
>>>> index a7cc17df8e..bfcd29bcdf 100644
>>>> --- a/config.h.in
>>>> +++ b/config.h.in
>>>> @@ -317,6 +317,9 @@
>>>>  /* Define if trunc is inlined on x86.  */
>>>>  #undef HAVE_X86_INLINE_TRUNC
>>>>
>>>> +/* Define if __builtin_fmod/__builtin_remainder is inlined on x86.  */
>>>> +#undef HAVE_X86_INLINE_FMOD
>>>> +
>>>>  /* Define if compiler allows add attribute after function declaration.  */
>>>>  #undef ATTR_AFTER_FUNC_DECL
>>>>
>>>> diff --git a/sysdeps/i386/fpu/e_fmod.c b/sysdeps/i386/fpu/e_fmod.c
>>>> index 281b23dffc..93b6f9d698 100644
>>>> --- a/sysdeps/i386/fpu/e_fmod.c
>>>> +++ b/sysdeps/i386/fpu/e_fmod.c
>>>> @@ -33,7 +33,21 @@ __fmod (double x, double y)
>>>>                         && !is_nan (hx)))
>>>>      return __math_invalid (x);
>>>>
>>>> +#if HAVE_X86_INLINE_FMOD
>>>
>>> Does __has_builtin (__builtin_fmod) work?  Can you define
>>> __builtin_fmod in x86/fpu/math-inline-asm.h
>>
>> __has_builtin (__builtin_fmod) doesn't work since GCC 12 just
>> calls the C function.  But it is still a good idea to put them in
>> x86/fpu/math-inline-asm.h.
> What do we gain by using __has_builtin here? I coded in the manner that
> if/when we raise the minimum required gcc to 13 we can just remove this
> support.

Ping.