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Re: [PATCH] [4.0] Fix performance regressions due to inlining
- From: Richard Sandiford <rsandifo at redhat dot com>
- To: Paul Schlie <schlie at comcast dot net>
- Cc: 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 08:40:09 +0000
- Subject: Re: [PATCH] [4.0] Fix performance regressions due to inlining
- References: <200503042007.58350.stevenb@suse.de><BE4E23C4.9599%schlie@comcast.net>
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.
Richard