------- Comment #4 from jakub at gcc dot gnu dot org 2008-01-20 19:26 -------
It fails even with gcc 4.1.2 and the same CFLAGS, and the problem is just buggy
inline assembly.
Following patch cures this for me:
--- hwfeatures.c.xx 2007-12-05 12:03:33.000000000 +0100
+++ hwfeatures.c 2008-01-20 19:54:54.000000000 +0100
@@ -79,13 +79,12 @@ detect_ia32_gnuc (void)
("pushl %%ebx\n\t" /* Save GOT register. */
"xorl %%eax, %%eax\n\t" /* 0 -> EAX. */
"cpuid\n\t" /* Get vendor ID. */
- "leal %0, %%eax\n\t" /* EBX,EDX,ECX -> VENDOR_ID. */
- "movl %%ebx, (%%eax)\n\t"
- "movl %%edx, 4(%%eax)\n\t"
- "movl %%ecx, 8(%%eax)\n\t"
+ "movl %%ebx, (%1)\n\t" /* EBX,EDX,ECX -> VENDOR_ID. */
+ "movl %%edx, 4(%1)\n\t"
+ "movl %%ecx, 8(%1)\n\t"
"popl %%ebx\n"
: "=m" (vendor_id)
- :
+ : "S" (&vendor_id[0])
: "%eax", "%ecx", "%edx", "cc"
);
vendor_id[12] = 0;
The problem is that %0 corresponding to "=m" is expanded when %esp is different
from what it has been originally on inline asm entry (and exit). Without
-fomit-frame-pointer GCC will usually use (%ebp+N) for %0, but with
-fomit-frame-pointer it uses (%esp+M), but as there is pushl %ebx before this,
it means the inline asm stores to a different location than expected.
--
jakub at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|WAITING |RESOLVED
Resolution| |INVALID
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34725
