------- Comment #8 from hjl dot tools at gmail dot com 2008-12-03 21:28 -------
(In reply to comment #5)
> (In reply to comment #4)
> > 4.3:
> > -O3 -march=native -funroll-loops -ffast-math ==> 4.376
> > -O3 -march=native -funroll-loops -ffast-math -fschedule-insns ==> 3.372
>
> strangely:
>
> http://gcc.gnu.org/onlinedocs/gcc-4.3.2/gcc/Optimize-Options.html#Optimize-Options
> suggests -fschedule-insns is enabled by default at -O3 ?
>
This may be related to PR 37565. i386.c has
void
optimization_options (int level, int size ATTRIBUTE_UNUSED)
{
/* For -O2 and beyond, turn off -fschedule-insns by default. It tends to
make the problem with not enough registers even worse. */
#ifdef INSN_SCHEDULING
if (level > 1)
flag_schedule_insns = 0;
#endif
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38306
