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Re: [PATCH] PR/34012, fwprop does not look at rtx_costs
- From: "Uros Bizjak" <ubizjak at gmail dot com>
- To: "GCC Patches" <gcc-patches at gcc dot gnu dot org>
- Cc: "Paolo Bonzini" <bonzini at gnu dot org>, "Richard Guenther" <rguenther at suse dot de>
- Date: Mon, 12 Nov 2007 09:24:55 +0100
- Subject: Re: [PATCH] PR/34012, fwprop does not look at rtx_costs
> > > Unlike CSE, fwprop has never looked at rtx_costs except for addressing
> > > mode selection. This causes pessimizations, for example when the same
> > > expensive constant is used in many insns. Then it is:
> 2007-11-07 Paolo Bonzini <firstname.lastname@example.org>
> Jakub Jelinek <email@example.com>
> PR rtl-optimization/34012
> * fwprop.c (try_fwprop_subst): Do not replace if the new
> SET_SRC has a higher cost than the old one.
> * gcc.target/i386/pr34012.c: New test.
> > Bootstrapped/regtested by Jakub on x86_64-linux, ppc64-linux (-m64
> > default) and ia64-linux. No regressions.
> This is ok. Please watch for any negative effects of this.
The referenced patch introduces:
Running /home/uros/gcc-test-svn/trunk/gcc/testsuite/gcc.target/i386/i386.exp ...
FAIL: gcc.target/i386/addr-sel-1.c scan-assembler a\\+1
FAIL: gcc.target/i386/addr-sel-1.c scan-assembler b\\+1
on 32bit x86 target.