On Fri, May 10, 2019 at 11:04:12AM +0200, Martin Liška wrote:
> --- a/gcc/config/i386/i386.h
> +++ b/gcc/config/i386/i386.h
> @@ -1906,6 +1906,9 @@ typedef struct ix86_args {
>
> #define CLEAR_RATIO(speed) ((speed) ? MIN (6, ix86_cost->move_ratio) : 2)
>
> +/* C library provides fast implementation of mempcpy function. */
> +#define TARGET_HAS_FAST_MEMPCPY_ROUTINE 1
> +
1) we shouldn't be adding further target macros, but target hooks
2) I don't think this is a property of the x86 target, but of x86 glibc,
so you should set it on x86 glibc only (i.e. i?86/x86_64 linux and hurd
when using glibc, not newlib, nor bionic/android, nor uclibc, nor musl)
> --- a/gcc/testsuite/gcc.c-torture/execute/builtins/mempcpy.c
> +++ b/gcc/testsuite/gcc.c-torture/execute/builtins/mempcpy.c
> @@ -56,9 +56,8 @@ main_test (void)
> if (__builtin_mempcpy (p, "ABCDE", 6) != p + 6 || memcmp (p, "ABCDE", 6))
> abort ();
>
> - /* If the result of mempcpy is ignored, gcc should use memcpy.
> - This should be optimized always, so set inside_main again. */
> - inside_main = 1;
> + /* Set inside main in order to not abort because of usafe of mempcpy. */
> + inside_main = 0;
> mempcpy (p + 5, s3, 1);
> if (memcmp (p, "ABCDEFg", 8))
> abort ();
Why this? Do you mean mempcpy is called here, even when the lhs is unused?
We should be calling memcpy in that case.
Jakub
