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Re: [tree-ssa] where to fix this?
- From: law at redhat dot com
- To: Daniel Berlin <dberlin at dberlin dot org>
- Cc: Roger Sayle <roger at eyesopen dot com>, gcc at gcc dot gnu dot org, Dale Johannesen <dalej at apple dot com>, Jan Hubicka <hubicka at ucw dot cz>, Jan Hubicka <jh at suse dot cz>
- Date: Tue, 06 Jan 2004 17:29:09 -0700
- Subject: Re: [tree-ssa] where to fix this?
- Reply-to: law at redhat dot com
In message <FFCAFC47-40A3-11D8-8CD1-000A95DA505C@dberlin.org>, Daniel Berlin wr
ites:
>> When we follow def-use chains in the dominator optimizer to reassociate
>> and simplify operands. The stuff we do right now is pretty simple, but
>> it's one of the two areas of the dominator optimizer that I do expect
>> will need to be extended.
>>
>
>I tried a variant on this back right before we had renaming SSA.
>It was a forward and backward substitution pass, which tried to see if
>any of the resulting expressions were GIMPLE (after trying folding, of
>course).
>They never were.
Apparently your code was buggy or you weren't looking at the right stuff.
I've definitely got cases where were substitution & folding results in
a gimple expression.
jeff