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Re: Autoincrement examples
- To: law at cygnus dot com
- Subject: Re: Autoincrement examples
- From: Joern Rennecke <amylaar at cygnus dot co dot uk>
- Date: Tue, 23 Nov 1999 15:06:12 +0000 (GMT)
- Cc: m dot hayes at elec dot canterbury dot ac dot nz, amylaar at cygnus dot co dot uk, gcc at gcc dot gnu dot org, amylaar at cygnus dot com
> > > - By processing each register separately, you miss register-register
> > > copies and three-address adds. Optimizing code with such constructs
> > > was actually the main objective of my patch. It actually reduces
> > > register pressure.
> > I have rarely found these cases to be important for autoinc address
> > generation. However, reduction of register pressure is a good thing.
> I am somewhat surprised that that this isn't caught by cases B, C & E, at
> least in limited forms.
The regmove patches from 1997 already addressed this kind of 'piecemeal'
optimization. But it turned out that many worthwhile optimizations
are only discernible as worthwhile when you look at the entire set
of related values.