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Re: [patch, fortran] PR 40628, front-end optimization pass


On Sun, Jul 18, 2010 at 09:11:38PM -0700, Jerry DeLisle wrote:
> On 07/18/2010 01:46 AM, Daniel Kraft wrote:
> >Hi Thomas,
> >
> >Thomas Koenig wrote:
> >>finally, here's the first attempt at a front-end optimization pass.
> >>Right now, it fixes PR 40626 and optimizes comparisons between variables
> >>(which only really is relevant for character comparisons). Many more
> >>things could (and should) be added over time.
> >
> 
> I like the idea as long as we do not duplicate middle-end work. If
> we can improve performance without sacrificing maintainability and
> correctness, I am all for it.  The idea of general passes is good.
> Rather than optimize.c maybe call it early_pass.c or whatever.

What I think would be very useful to do in -fwhole-file mode do a pass
through the front-end trees and improve using that slightly e.g.
dependency.c stuff (unless we jump to middle-end arrays, that's an easy way
to get rid e.g. of unnecessary array temporaries).  E.g. in tonto POINTER
vars are ALLOCATED in one routine and not changed afterwards, such vars
could be handled like allocatables.

	Jakub


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