Re: [PATCH] i386: Fix GCC running out of registers for bits/string.h

[Jakub Jelinek <jakub at redhat dot com>]

On Wed, Jun 08, 2005 at 07:12:06PM +0100, Maciej W. Rozycki wrote:
> --- glibc-2.3.5.macro/sysdeps/i386/bits/string.h	2004-06-15 20:11:53.000000000 +0000
> +++ glibc-2.3.5/sysdeps/i386/bits/string.h	2005-06-02 00:02:01.000000000 +0000
> @@ -671,7 +671,7 @@ strcspn (__const char *__s, __const char
>       "2:\n\t"
>       "popl	%%ebx"
>       : "=&S" (__res), "=&a" (__d0), "=&c" (__d1), "=&D" (__d2)
> -     : "d" (__reject), "0" (__s), "1" (0), "2" (0xffffffff),
> +     : "g" (__reject), "0" (__s), "1" (0), "2" (0xffffffff),
>         "m" ( *(struct { char __x[0xfffffff]; } *)__s)
>       : "cc");
>    return (__res - 1) - __s;

E.g. this can't be right.
strcspn (__const char *__s, __const char *__reject)
{
  register unsigned long int __d0, __d1, __d2;
  register char *__res;
  __asm__ __volatile__
    ("pushl     %%ebx\n\t"
     "cld\n\t"
     "movl      %4,%%edi\n\t"
     "repne; scasb\n\t"
     "notl      %%ecx\n\t"
     "decl      %%ecx\n\t"
     "movl      %%ecx,%%ebx\n"
     "1:\n\t"
     "lodsb\n\t"
     "testb     %%al,%%al\n\t"
     "je        2f\n\t"
     "movl      %4,%%edi\n\t"
     "movl      %%ebx,%%ecx\n\t"
     "repne; scasb\n\t"
     "jne       1b\n"
     "2:\n\t"
     "popl      %%ebx"
     : "=&S" (__res), "=&a" (__d0), "=&c" (__d1), "=&D" (__d2)
     : "d" (__reject), "0" (__s), "1" (0), "2" (0xffffffff),
       "m" ( *(struct { char __x[0xfffffff]; } *)__s)
     : "cc");
  return (__res - 1) - __s;
}

Because of the pushl there, __reject's constraint must not allow
memory, as say 16(%esp) is valid "m" (as well as "g") operand,
but as GCC doesn't know about the pushl, it would use a wrong value.

	Jakub