RE: [PATCH] [PING] Inline mempcpy

["Wilco Dijkstra" <wdijkstr at arm dot com>]

> Wilco Dijkstra wrote:
> > Joseph Myers wrote:
> > On Mon, 18 May 2015, Wilco Dijkstra wrote:
> >
> > This seems plausible, subject to getting per-architecture agreement (for
> > each architecture with mempcpy.S) on whether to define
> > _HAVE_STRING_ARCH_mempcpy.  Although there may be the question of whether
> > __extern_always_inline should be defined at all for !__GNUC_PREREQ (3,2)
> > (i.e. when the always_inline attribute isn't supported).
> 
> It would be good to fix the *always_inline defines, but I for now I've added
> an extra check for __GNUC_PREREQ (3,2) to be sure we don't fail to inline on
> really old GCCs. So here's the actual patch - I've disabled inlining for SPARC,
> and from previous comments it seems people prefer the inline mempcpy on x64/x86
> and PPC (I've included the maintainers for those arches to agree/veto).
> 
> OK for commit?
> 
> Wilco
> 
> ChangeLog:
> 2015-05-20  Wilco Dijkstra  <wdijkstr@arm.com>
> 
>         * string/string.h: (mempcpy): Redirect to __mempcpy_inline.
>         (__mempcpy): Likewise.  (__mempcpy_inline): New inline function.
>         * sysdeps/sparc/bits/string.h: (_HAVE_STRING_ARCH_mempcpy): Define.
> 
> ---
>  string/string.h             | 19 +++++++++++++++++++
>  sysdeps/sparc/bits/string.h |  3 +++
>  2 files changed, 22 insertions(+)
> 
> diff --git a/string/string.h b/string/string.h
> index 54a4d39..3ab7103 100644
> --- a/string/string.h
> +++ b/string/string.h
> @@ -636,6 +636,25 @@ extern char *basename (const char *__filename) __THROW __nonnull ((1));
>  # endif
>  #endif
> 
> +#if defined __USE_GNU && defined __OPTIMIZE__ \
> +    && defined __extern_always_inline && __GNUC_PREREQ (3,2)
> +# if !defined _FORCE_INLINES && !defined _HAVE_STRING_ARCH_mempcpy
> +
> +#undef mempcpy
> +#undef __mempcpy
> +#define mempcpy(dest, src, n) __mempcpy_inline (dest, src, n)
> +#define __mempcpy(dest, src, n) __mempcpy_inline (dest, src, n)
> +
> +__extern_always_inline void *
> +__mempcpy_inline (void *__restrict __dest,
> +		  const void *__restrict __src, size_t __n)
> +{
> +  return (char *) memcpy (__dest, __src, __n) + __n;
> +}
> +
> +# endif
> +#endif
> +
>  __END_DECLS
> 
>  #endif /* string.h  */
> diff --git a/sysdeps/sparc/bits/string.h b/sysdeps/sparc/bits/string.h
> index 36fbb4c..4eb9447 100644
> --- a/sysdeps/sparc/bits/string.h
> +++ b/sysdeps/sparc/bits/string.h
> @@ -26,3 +26,6 @@
>  /* sparc32 and sparc64 strchr(x, '\0') perform better than
>     __rawmemchr(x, '\0').  */
>  #define _HAVE_STRING_ARCH_strchr 1
> +
> +/* Don't inline mempcpy into memcpy as sparc has an optimized mempcpy.  */
> +#define _HAVE_STRING_ARCH_mempcpy 1
> --
> 1.9.1