linux-kernel - wrong constraints "=g" at include/asm-i386/string.h, line 186?

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Message-ID: <824323160707260458h490e9ae5la44aabcfa413bba7@mail.gmail.com>
Date:	Thu, 26 Jul 2007 19:58:58 +0800
From:	"Jian-Xin Lai" <laijx03@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: wrong constraints "=g" at include/asm-i386/string.h, line 186?

Hi,

The kernel version is 2.6.20.7. In include/asm-i386/string.h, line 169~185:
static inline char * strrchr(const char * s, int c)
{
int d0, d1;
register char * __res;
__asm__ __volatile__(
        "movb %%al,%%ah\n"
        "1:\tlodsb\n\t"
        "cmpb %%ah,%%al\n\t"
        "jne 2f\n\t"
        "leal -1(%%esi),%0\n"                                    (*)
        "2:\ttestb %%al,%%al\n\t"
        "jne 1b"
        :"=g" (__res), "=&S" (d0), "=&a" (d1)               (**)
        :"0" (0),"1" (s),"2" (c)
        :"memory");
return __res;
}

The 'lea' instruction needs a register here (*), but "g" (**) means
any registers, memory or immediate integer. Is it correct? If the
compiler do not place the __res into a register, the compilation will
fail. Should it be "r"?
Thank you very much.

-- 
Regards,
Lai Jian-Xin
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