From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeffrey A Law To: egcs@cygnus.com Cc: kthomas@gwdg.de Subject: Re: Optimizations Date: Sun, 14 Dec 1997 20:14:00 -0000 Message-id: <25425.882159453@hurl.cygnus.com> References: <19971215000809.60319@cerebro.laendle> X-SW-Source: 1997-12/msg00816.html In message < 19971215000809.60319@cerebro.laendle >you write: > On Sun, Dec 14, 1997 at 02:34:36PM +0100, Philipp Thomas wrote: > > Marc Lehmann wrote: > > > -fschedule-insns is a *loss* on x86 cpu's! > > > > care to explain why it is a loss (and most probably also -fschedule-insns > 2) > > ? > > AFAIR -fschedule-insns (as opposed to -fschedule-insns2) is normally a loss > sicne the first scheduling pass is done before register allocation, so the > register pressure increases and local/global get's problems. (for fpu code > it _could_ be beneficial, though). To be more correct it may be a loss for machines with a limited number of registers (such as the x86). On machines with a generous number of registers -fschedule-insns is generally a win. jeff