On Wed, Mar 28, 2018 at 04:18:45PM +0200, Martin Liška wrote:
> 2018-03-14 Martin Liska <mli...@suse.cz>
>
> PR middle-end/81657
> * builtins.c (expand_builtin_memory_copy_args): Handle situation
> when libc library provides a fast mempcpy implementation/
> * config/i386/i386-protos.h (gnu_libc_func_speed): New.
> * config/i386/i386.c (enum libc_speed): Likewise.
> (ix86_libc_func_speed): Likewise.
> (TARGET_LIBC_FUNC_SPEED): Likewise.
> * coretypes.h (enum libc_speed): Likewise.
> * doc/tm.texi: Document new target hook.
> * doc/tm.texi.in: Likewise.
> * expr.c (emit_block_move_hints): Handle libc bail out argument.
> * expr.h (emit_block_move_hints): Add new parameters.
> * target.def: Add new hook.
> * targhooks.c (enum libc_speed): New enum.
> (default_libc_func_speed): Provide a default hook
> implementation.
> * targhooks.h (default_libc_func_speed): Likewise.
>
> gcc/testsuite/ChangeLog:
>
> 2018-03-14 Martin Liska <mli...@suse.cz>
>
> * gcc.dg/string-opt-1.c: Adjust scans for i386 and glibc target
> and others.
> /* Copy word part most expediently. */
> + bool libcall_avoided = false;
> dest_addr = emit_block_move_hints (dest_mem, src_mem, len_rtx,
> CALL_EXPR_TAILCALL (exp)
> && (endp == 0 || target == const0_rtx)
> ? BLOCK_OP_TAILCALL : BLOCK_OP_NORMAL,
> expected_align, expected_size,
> - min_size, max_size, probable_max_size);
> + min_size, max_size, probable_max_size,
> + avoid_libcall ? &libcall_avoided: NULL);
Missing space before :.
> +
> + if (libcall_avoided)
> + return NULL_RTX;
>
> --- a/gcc/config/i386/i386-protos.h
> +++ b/gcc/config/i386/i386-protos.h
> @@ -47,6 +47,8 @@ extern void ix86_reset_previous_fndecl (void);
>
> extern bool ix86_using_red_zone (void);
>
> +extern enum libc_speed gnu_libc_func_speed (int fn);
Here you declare gnu_libc_func_speed.
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -2735,6 +2735,27 @@ ix86_using_red_zone (void)
> && (!cfun->machine->has_local_indirect_jump
> || cfun->machine->indirect_branch_type == indirect_branch_keep));
> }
> +
> +/* This hook determines whether a function from libc has a fast
> implementation
> + FN is present at the runtime. We override it for i386 and glibc C library
> + as this combination provides fast implementation of mempcpy function. */
> +
> +enum libc_speed
> +ix86_libc_func_speed (int fn)
But define a different function.
> +{
> + enum built_in_function f = (built_in_function)fn;
> +
> + if (!OPTION_GLIBC)
> + return LIBC_UNKNOWN_SPEED;
OPTION_GLIBC is only defined if linux.h is included, so I think you break
all other x86 targets this way. The hook should have linux in the name,
perhaps defined only in config/i386/linux.h and redefined in i386.c through
#ifdef SUBTARGET_LIBC_FUNC_SPEED
#undef TARGET_LIBC_FUNC_SPEED
#define TARGET_LIBC_FUNC_SPEED SUBTARGET_LIBC_FUNC_SPEED
#endif
or something similar.
Otherwise LGTM, but please get approval also from Richi (for the generic part)
and
Uros (for the backend side).
Jakub
