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Re: [tree-ssa] Removing redundant loads


On Thursday, May 29, 2003, at 05:21 PM, Diego Novillo wrote:

On Thu, 2003-05-29 at 17:13, Daniel Berlin wrote:
On Thursday, May 29, 2003, at 04:38 PM, law@redhat.com wrote:


I mentioned at the GCC summit, I had a nice one line patch which
allowed
tree-ssa to remove redundant loads at basically no cost.



And this patch rapes the ability of load PRE to work.
Sigh.

Well, as with anything done in the renaming pass, these tricks will only
catch total redundancies. So, yes, it may hinder PRE. 
It's not just PRE it'll hinder, of course.
It will hinder any load placement optimization.

 But don't
despair, nothing is written in stone here.

What we should do is make these transformations conditional as any other
transformation. Later on, when PRE is finished, we can start playing
the flags game with SPEC or what-have-you.

PRE is of course, waiting on live range out-of-ssa stuff.

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