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Re: Compilation performance comparison of 3.5.0 and TreeSSA treeson MICO sources as requested in: [tree-ssa] Merge status 2004-05-03
- From: Diego Novillo <dnovillo at redhat dot com>
- To: Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>
- Cc: "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
- Date: Wed, 05 May 2004 10:14:16 -0400
- Subject: Re: Compilation performance comparison of 3.5.0 and TreeSSA treeson MICO sources as requested in: [tree-ssa] Merge status 2004-05-03
- Organization: Red Hat Canada
- References: <10405050108.AA04500@vlsi1.ultra.nyu.edu>
On Tue, 2004-05-04 at 21:08, Richard Kenner wrote:
> The gimplification process tends to create extremely bloated RTL.
> Why? I would expect it to produce exactly the same RTL as that produced
> before tree-ssa if no optimization is done.
Mostly because of the breaking down of expressions into small trees,
which are friendlier to the RTL expanders. That's the reason we have a
tree recombination pass at the end of tree optimization.
Of course, most of the bloat comes when you don't allow the tree
optimizers to run.