This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug rtl-optimization/31849] [4.2/4.3 Regression] Code size regression caused by fix to PR 31360
- From: "rakdver at kam dot mff dot cuni dot cz" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 7 May 2007 08:38:50 -0000
- Subject: [Bug rtl-optimization/31849] [4.2/4.3 Regression] Code size regression caused by fix to PR 31360
- References: <bug-31849-374@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #5 from rakdver at kam dot mff dot cuni dot cz 2007-05-07 09:38 -------
Subject: Re: [4.2/4.3 Regression] Code size regression caused by fix to PR
31360
> (In reply to comment #2)
> > > 1) Hoists a register containing 0 out of the loop
> > The correct thing to do.
> >
> Not necessarily. Hoisting literal constants means that opportunities to simply
> insns based on that constant are potentially lost.
This could be prevented if invariant motion added equivalence notes;
nevertheless,
one could argue that such simplifications should have been performed
before loop invariant motion (in cse).
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31849