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Re: [tree-ssa] CCP inefficiencies
- From: law at redhat dot com
- To: Diego Novillo <dnovillo at redhat dot com>
- Cc: "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
- Date: Thu, 13 Feb 2003 09:10:25 -0700
- Subject: Re: [tree-ssa] CCP inefficiencies
- Reply-to: law at redhat dot com
In message <1045151865.10505.54.camel@frodo>, Diego Novillo writes:
>On Wed, 2003-02-12 at 18:08, law@redhat.com wrote:
>
>> It looks like a lot of the problem is the over-eager copying of nodes
>> so that we can replace their operands and try to fold them. This is
>> in itself rather expensive, but it also creates lots of garbage for
>> the collector to clean up. Ugh.
>>
>Yeah. Attribute that to Diego being a lazy bum(1). I originally had
>the idea of having some sort of undo buffer so that CCP could try the
>replacement and fold, but copying the expression tree was so much easier
>:)
Or a non-destructive simplifier. I'm not sure which is going to make
more sense, but it's pretty clear we need something better than just
copying the nodes.
Jeff