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[Bug target/23360] [4.1 regression] -ffast-math startup broken on i686 (maybe Athlon-xp)
- From: "hjl at lucon dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 12 Aug 2005 21:51:05 -0000
- Subject: [Bug target/23360] [4.1 regression] -ffast-math startup broken on i686 (maybe Athlon-xp)
- References: <20050812184154.23360.tkoenig@gcc.gnu.org>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From hjl at lucon dot org 2005-08-12 21:51 -------
For some reason, ldmxcsr doesn't work on your machine. The assembly code looks
correct to me. I don't have any problems on IA32. I can only assume that you
have a hardware or OS related issue. Can you verify if ldmxcsr works on your
machine?
[hjl@gnu-13 tmp]$ cat x.c
#define MXCSR_DAZ (1 << 6) /* Enable denormals are zero mode */
#define MXCSR_FTZ (1 << 15) /* Enable flush to zero mode */
int
main (void)
{
{
unsigned int mxcsr = __builtin_ia32_stmxcsr ();
mxcsr |= MXCSR_DAZ | MXCSR_FTZ;
__builtin_ia32_ldmxcsr (mxcsr);
}
return 0;
}
[hjl@gnu-13 tmp]$ gcc x.c
[hjl@gnu-13 tmp]$ ./a.out
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23360