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Re: [patch] Strength reduction for autoincrement generation
- To: Michael Hayes <m dot hayes at elec dot canterbury dot ac dot nz>
- Subject: Re: [patch] Strength reduction for autoincrement generation
- From: Bernd Schmidt <bernds at cambridge dot redhat dot com>
- Date: Mon, 12 Feb 2001 13:06:13 +0000 (GMT)
- Cc: <gcc-patches at gcc dot gnu dot org>
On Sun, 11 Feb 2001, Michael Hayes wrote:
> > > 2001-01-23 Michael Hayes <m.hayes@elec.canterbury.ac.nz>
> > >
> > > * loop.c (loop_giv_reduce_benefit): Tweak autoincrement generation
> > > heuristic.
>
> and after a short discussion the thread died. This patch provides
> a large improvement for autoincrement generation with small loops:
> to be blunt, without it the generated code for the c4x is appalling.
>
> Can I commit it?
Ok. Although you probably ought to be aware that it's likely to be broken
again in the future when someone else tries to modify that code: if the c4x
relies so heavily on an obscure heuristic, something is wrong with it.
I briefly ran a few tests with an sh compiler, and the effect of the patch
seems tolerable on the whole (even if it seems to do stupid things for one
or two testcases).
Bernd