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Re: [patch] Tweak for constrain_operands

From: bernds_cb1 at t-online dot de (Bernd Schmidt)
To: Steven Bosscher <stevenb at suse dot de>
Cc: gcc-patches at gcc dot gnu dot org
Date: Mon, 31 Jan 2005 14:14:14 +0100
Subject: Re: [patch] Tweak for constrain_operands
References: <200501310819.11057.stevenb@suse.de>

Steven Bosscher wrote:

There is no need to look for earlyclobber classes if we did
not see an '&' constraint.  We also do not have to look at
all operands from 0 to n_operands - just remember where we
saw the '&'.  This gives me about half a percent on all the
components of cc1.  Not surprising because for the i386 and
rs6000 ports only ~10% of all insns have an earlyclobber
constraint.

Bootstrapped and tested on x86_64-suse-linux-gnu. OK?

Looks reasonable enough, although I'm surprised it makes such a difference (and I can reproduce only about a .2% speedup on i686-linux).

Ok, but please post a ChangeLog entry next time.

Bernd

References:
- [patch] Tweak for constrain_operands
  - From: Steven Bosscher

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