[Bug middle-end/90263] Calls to mempcpy should use memcpy

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90263

--- Comment #14 from Martin Liška <marxin at gcc dot gnu.org> ---
Created attachment 46262
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46262&action=edit
Patch candidate

Patch candidate that handles:

$ cat ~/Programming/testcases/mempcpy.c
int *mempcopy2 (int *p, int *q, long n)
{
  return __builtin_mempcpy (p, q, n);
}

$ ./xgcc -B. -O2 -S ~/Programming/testcases/mempcpy.c -o/dev/stdout
...
mempcopy2:
.LFB0:
        .cfi_startproc
        pushq   %rbx
        .cfi_def_cfa_offset 16
        .cfi_offset 3, -16
        movq    %rdx, %rbx
        call    memcpy
        addq    %rbx, %rax
        popq    %rbx
        .cfi_def_cfa_offset 8
        ret
...

There's a single failing test: gcc.dg/20050503-1.c