From: Florian Weimer <fw@deneb.enyo.de>
To: Stefan Liebler via Libc-alpha <libc-alpha@sourceware.org>
Cc: Stefan Liebler <stli@linux.ibm.com>
Subject: Re: [PATCH v2] S390: Allow "v" constraint for long double math_opt_barrier and math_force_eval with GCC 11.
Date: Wed, 31 Mar 2021 16:23:44 +0200 [thread overview]
Message-ID: <87czvfqu4v.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <20210331141701.1339437-1-stli@linux.ibm.com> (Stefan Liebler via Libc-alpha's message of "Wed, 31 Mar 2021 16:17:01 +0200")
* Stefan Liebler via Libc-alpha:
> Starting with GCC 11, long double values can also be processed in vector
> registers if build with -march >= z14. Then GCC defines the
> __LONG_DOUBLE_VX__ macro.
>
> FYI: GCC commit "IBM Z: Introduce __LONG_DOUBLE_VX__ macro"
> https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=f47df2af313d2ce7f9149149010a142c2237beda
> ---
> sysdeps/s390/fpu/math-barriers.h | 21 +++++++++++++++++++--
> 1 file changed, 19 insertions(+), 2 deletions(-)
>
> diff --git a/sysdeps/s390/fpu/math-barriers.h b/sysdeps/s390/fpu/math-barriers.h
> index 68a3e55098..13fd30017f 100644
> --- a/sysdeps/s390/fpu/math-barriers.h
> +++ b/sysdeps/s390/fpu/math-barriers.h
> @@ -21,13 +21,26 @@
>
> #ifdef HAVE_S390_VX_GCC_SUPPORT
> # define ASM_CONSTRAINT_VR "v"
> +# ifdef __LONG_DOUBLE_VX__
> +/* Starting with gcc 11, long double values can also be processed in vector
> + registers if build with -march >= z14. Then GCC defines the
> + __LONG_DOUBLE_VX__ macro. */
> +# define ASM_LONG_DOUBLE_IN_VR 1
> +# else
> +# define ASM_LONG_DOUBLE_IN_VR 0
> +# endif
> #else
> # define ASM_CONSTRAINT_VR
> +# define ASM_LONG_DOUBLE_IN_VR 0
> #endif
>
> #define math_opt_barrier(x) \
> ({ __typeof (x) __x = (x); \
> - if (__builtin_types_compatible_p (__typeof (x), _Float128)) \
> + if (! ASM_LONG_DOUBLE_IN_VR \
> + && (__builtin_types_compatible_p (__typeof (x), _Float128) \
> + || __builtin_types_compatible_p (__typeof (x), long double) \
> + ) \
> + ) \
> __asm__ ("# math_opt_barrier_f128 %0" : "+fm" (__x)); \
> else \
> __asm__ ("# math_opt_barrier %0" \
> @@ -35,7 +48,11 @@
> __x; })
> #define math_force_eval(x) \
> ({ __typeof (x) __x = (x); \
> - if (__builtin_types_compatible_p (__typeof (x), _Float128)) \
> + if (! ASM_LONG_DOUBLE_IN_VR \
> + && (__builtin_types_compatible_p (__typeof (x), _Float128) \
> + || __builtin_types_compatible_p (__typeof (x), long double) \
> + ) \
> + ) \
> __asm__ __volatile__ ("# math_force_eval_f128 %0" \
> : : "fm" (__x)); \
> else \
This version looks good to me, thanks.
next prev parent reply other threads:[~2021-03-31 14:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-31 14:17 Stefan Liebler
2021-03-31 14:23 ` Florian Weimer [this message]
2021-04-01 7:15 ` Stefan Liebler
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