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

[Denis Vlasenko <vda at ilport dot com dot ua>]

On Wednesday 08 June 2005 21:12, Maciej W. Rozycki wrote:
> Hello,
> 
>  When building for the i386 as follows:
> 
> $ ../configure --prefix=/usr --enable-add-ons --enable-omitfp --build=i386-linux
> $ make
> 
> using GCC 4.0.0 I have got the following error:
> 
> dcigettext.c: In function '_nl_find_msg':
> ../sysdeps/i386/bits/string.h:655: error: can't find a register in class 'GENERAL_REGS' while reloading 'asm'

Cannot reproduce it here in a isolated testcase.
This one compiles with gcc 4.0.0 just fine:

t.c
===
#define NL "\n"

__const char *
strcspn (__const char *__s, __const char *__reject)
{
        unsigned long int __eax, __ebx, __ecx, __edi;
        char *__esi;

        __asm__ __volatile__(NL
        "       cld" NL
        "       movl    %5,%%edi" NL
        "       repne; scasb" NL
        "       notl    %%ecx" NL
        "       leal    -1(%%ecx),%%ebx" NL
        "1:" NL
        "       lodsb" NL
        "       testb   %%al,%%al" NL
        "       je      2f" NL
        "       movl    %5,%%edi" NL
        "       movl    %%ebx,%%ecx" NL
        "       repne; scasb" NL
        "       jne     1b" NL
        "2:" NL
        : "=&S" (__esi), "=&a" (__eax), "=&b" (__ebx), "=&c" (__ecx), "=&D" (__edi)
        : "d" (__reject), "0" (__s), "1" (0), "2" (0xffffffff),
                "m" ( *(struct { char __x[0xfffffff]; } *)__s)
        : "cc");

        return (__esi - 1) - __s;
}

# gcc -O2 -fomit-frame-pointer -S t.c

strcspn:
        pushl   %ebp
        pushl   %edi
        pushl   %esi
        pushl   %ebx
        pushl   %ecx
        movl    24(%esp), %ebp
        movl    28(%esp), %edx
        xorl    %ecx, %ecx
        movl    $-1, %ebx
        movl    %ebp, %esi
        movl    %ecx, %eax
#APP

        cld
        movl    %edx,%edi
        repne; scasb
        notl    %ecx
        leal    -1(%ecx),%ebx
1:
        lodsb
        testb   %al,%al
        je      2f
        movl    %edx,%edi
        movl    %ebx,%ecx
        repne; scasb
        jne     1b
2:

#NO_APP
        movl    %esi, %edx
        subl    %ebp, %edx
        leal    -1(%edx), %eax
        popl    %edx
        popl    %ebx
        popl    %esi
        popl    %edi
        popl    %ebp
        ret
--
vda