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Re: [PATCH] [4.0] Fix performance regressions due to inlining
- From: Richard Earnshaw <rearnsha at gcc dot gnu dot org>
- To: Richard Sandiford <rsandifo at redhat dot com>
- Cc: Paul Schlie <schlie at comcast dot net>, Steven Bosscher <stevenb at suse dot de>, Patch List <gcc-patches at gcc dot gnu dot org>, Mark Mitchell <mark at codesourcery dot com>, Richard Guenther <rguenth at tat dot physik dot uni-tuebingen dot de>
- Date: Tue, 08 Mar 2005 10:30:31 +0000
- Subject: Re: [PATCH] [4.0] Fix performance regressions due to inlining
- Organization: GNU
- References: <200503042007.58350.stevenb@suse.de> <BE4E23C4.9599%schlie@comcast.net> <wvnzmxefs46.fsf@talisman.cambridge.redhat.com>
On Tue, 2005-03-08 at 08:40, Richard Sandiford wrote:
> Paul Schlie <schlie@comcast.net> writes:
> > - although I may misunderstand, on a typical 3-operand machine:
> >
> > add r<a> r<b> c<> ; therefore a cost estimate of 1 seems good.
> >
> > but on a 2-operand machine, typical of lower-end arm, mips, etc.:
> >
> > mov r<a> c<c> ; being typical, a cost of 2 seems reasonable
> > add r<a> r<b> ; as it stands today.
>
> Huh? MIPS and ARM are basically three-operand ISAs. The new heuristics
> definitely make sense to me from a MIPS POV.
Thumb is a two-operand ISA.
R.