i386 performance problem due to local-alloc.c change
Jeffrey A Law
Wed Jun 24 00:16:00 GMT 1998
In message < 199806240650.CAA13269@jwlab.FEITH.COM >you write:
> I seem to be seeing around a 10 percent performance hit when
> running the crafty chess benchmark and the Brl-Cad raytracing
> benchmarks on an Intel Pentium II with:
> Tue Jun 9 12:36:16 1998 Jeffrey A Law (email@example.com)
> * Makefile.in (local-alloc.o): Depend on insn-attr.h.
> * local-alloc.c (block_alloc): Avoid creating false
> dependencies for targets which use instruction scheduling.
> installed. If I remove this patch then life gets better (not to
> mention faster :-).
Hmmm, I thought the x86 didn't do any local register allocation due to
the definition to CLASS_LIKELY_SPILLED_P. So I'm a little suprised.
One thought would be to disable that code if SMALL_REGISTER_CLASSES
is nonzero. That's probably the right thing to do.
ps. It's as much as a 25% improvement for ugly Fortran code on my PAs :-)
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