Re: [Patch, fortran] PR 49010/24518 MOD/MODULO fixes, take 2

[Janne Blomqvist <blomqvist dot janne at gmail dot com>]

PING #2

On Thu, Apr 26, 2012 at 12:20 AM, Janne Blomqvist
<blomqvist.janne@gmail.com> wrote:
> PING!
>
> On Thu, Apr 19, 2012 at 00:46, Janne Blomqvist
> <blomqvist.janne@gmail.com> wrote:
>> Hi,
>>
>> the attached patch implements a few fixes and cleanups for the MOD and
>> MODULO intrinsics.
>>
>> - When the arguments are constant, use mpfr_fmod instead of the naive
>> algorithms which are numerically unstable for large arguments. This
>> extends the PR 24518 fix to constant arguments as well, and makes the
>> compile-time evaluation match the runtime implementation which also
>> uses fmod in the same manner.
>>
>> - Remove the old fallback path for the case builtin_fmod is not
>> available, as the builtin is AFAICS always available.
>>
>> - Specify the behavior wrt. the sign and magnitude of the result,
>> mention this in the documentation. This includes signed zeros which
>> now behave similar to other finite values. I.e. for MOD(A, P) the
>> result has the sign of A and a magnitude less than that of P, and for
>> MODULO(A, P) the result has the sign of P and a magnitude less than
>> that of P. As a (minor?) caveat, at runtime this depends on the
>> implementation of the fmod function in the target C library. But, a
>> fmod that follows C99 Annex F implements this behavior.
>>
>> Regtested on x86_64-unknown-linux-gnu, Ok for trunk?
>>
>> 2012-04-19 ÂJanne Blomqvist Â<jb@gcc.gnu.org>
>>
>> Â Â Â ÂPR fortran/49010
>> Â Â Â ÂPR fortran/24518
>> Â Â Â Â* intrinsic.texi (MOD, MODULO): Mention sign and magnitude of result.
>> Â Â Â Â* simplify.c (gfc_simplify_mod): Use mpfr_fmod.
>> Â Â Â Â(gfc_simplify_modulo): Likewise, use copysign to fix the result if
>> Â Â Â Âzero.
>> Â Â Â Â* trans-intrinsic.c (gfc_conv_intrinsic_mod): Remove fallback as
>> Â Â Â Âbuiltin_fmod is always available. For modulo, call copysign to fix
>> Â Â Â Âthe result when signed zeros are enabled.
>>
>>
>> --
>> Janne Blomqvist
>
>
>
> --
> Janne Blomqvist



-- 
Janne Blomqvist