From: Jeffrey A Law <law@cygnus.com>
To: egcs@cygnus.com
Cc: kthomas@gwdg.de
Subject: Re: Optimizations
Date: Sun, 14 Dec 1997 20:14:00 -0000 [thread overview]
Message-ID: <25425.882159453@hurl.cygnus.com> (raw)
In-Reply-To: <19971215000809.60319@cerebro.laendle>
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
next prev parent reply other threads:[~1997-12-14 20:14 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
1997-12-09 9:52 Optimizations David M. Ronis
1997-12-09 11:19 ` Optimizations Jeffrey A Law
1997-12-10 10:46 ` [EGCS] Optimizations Marc Lehmann
1997-12-14 5:39 ` Philipp Thomas
1997-12-14 15:14 ` Optimizations Marc Lehmann
1997-12-14 20:14 ` Jeffrey A Law [this message]
1997-12-14 14:30 [EGCS] Optimizations meissner
1997-12-15 5:38 ` Optimizations Marc Lehmann
1997-12-15 11:29 ` Optimizations Dave Love
1997-12-15 15:43 ` Optimizations Marc Lehmann
[not found] ` <19971216000653.24186.cygnus.egcs@cerebro.laendle>
1997-12-23 7:51 ` Optimizations Stan Cox
2000-03-10 1:46 Optimizations Virgil Palanciuc
2003-01-14 22:58 optimizations Reza Roboubi
2003-01-15 0:15 ` optimizations Andrew Pinski
2003-01-15 5:10 ` optimizations Reza Roboubi
2003-01-15 6:31 ` optimizations Reza Roboubi
2003-01-15 17:37 ` optimizations Andrew Pinski
2003-01-15 17:46 ` optimizations Reza Roboubi
2003-01-15 23:20 optimizations Bonzini
2003-01-16 10:53 ` optimizations Reza Roboubi
2003-01-16 11:03 ` optimizations tm_gccmail
2003-01-16 12:34 ` optimizations Reza Roboubi
2003-02-18 18:13 ` optimizations Håkan Hjort
2003-02-18 18:16 ` optimizations Andrew Pinski
2003-02-18 18:17 ` optimizations Zack Weinberg
2003-02-18 18:40 ` optimizations Håkan Hjort
2003-02-19 5:02 ` optimizations David Edelsohn
2003-01-16 11:53 ` optimizations Paolo Bonzini
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