On Tue, 16 Aug 2022, Jakub Jelinek wrote:
> On Tue, Aug 16, 2022 at 11:41:06AM +0000, Richard Biener wrote:
> > Can you also amend the extend.texi documentation? I think the
> > behavior will be special enough to worth mentioning it (I don't see
> > any of -ffinite-math-only effect on isnan/isinf mentioned though).
>
> Like this?
Yes.
Thanks,
Richard.
> --- gcc/doc/extend.texi.jj 2022-08-16 13:23:04.227103773 +0200
> +++ gcc/doc/extend.texi 2022-08-16 13:56:01.250769807 +0200
> @@ -13557,6 +13557,8 @@ In the same fashion, GCC provides @code{
> @code{isinf_sign}, @code{isnormal} and @code{signbit} built-ins used with
> @code{__builtin_} prefixed. The @code{isinf} and @code{isnan}
> built-in functions appear both with and without the @code{__builtin_} prefix.
> +With @code{-ffinite-math-only} option the @code{isinf} and @code{isnan}
> +built-in functions will always return 0.
>
> GCC provides built-in versions of the ISO C99 floating-point rounding and
> exceptions handling functions @code{fegetround}, @code{feclearexcept} and
> @@ -14496,6 +14498,12 @@ Note while the parameter list is an
> ellipsis, this function only accepts exactly one floating-point
> argument. GCC treats this parameter as type-generic, which means it
> does not do default promotion from float to double.
> +This built-in function can work even without the non-default
> +@code{-fsignaling-nans} option, although if a signaling NaN is computed,
> +stored or passed as argument to some function other than this built-in
> +in the current translation unit, it is safer to use @code{-fsignaling-nans}.
> +With @code{-ffinite-math-only} option this built-in function will always
> +return 0.
> @end deftypefn
>
> @deftypefn {Built-in Function} int __builtin_ffs (int x)
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)
