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Re: GCSE store motion


On Tue, 14 May 2002, David S. Miller wrote:

> 
> While walking over diffs between 3.1 and the mainline I came across
> PR/5200.  Basically the fix on the branch just disabled store-motion
> in GCSE.
> 
> This is one of those "fix it properly on the mainline" cases.
> 
> So who is going to step up and work on fixing store motion?

I had too much fun funking around with hard to track down alias problems
the last time i spent a month trying to improve and fix the RTL version.
It's rather easy to fix what's there now, but it doesn't do anything 
(really. It shows 0% difference on benchmarks), except for whatever 
special case it's currently designed to handle.

So i'm out.

Though, on the upside, SSAPRE will be able to move them soon enough, 
which, except on x86, will likely give you most of the benefit (on x86, 
of course, store motion afters spilling would likely be helpful) 

I'm concentrating on the strength reduction stuff and cleaning up the 
points-to analysis needed first, however.


--Dan


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