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Re: Project RABLET
- From: "Seongbae Park" <seongbae dot park at gmail dot com>
- To: "Andrew MacLeod" <amacleod at redhat dot com>
- Cc: "gcc mailing list" <gcc at gcc dot gnu dot org>
- Date: Fri, 23 Jun 2006 17:09:09 -0700
- Subject: Re: Project RABLET
- References: <1151090584.13088.26.camel@localhost.localdomain>
On 6/23/06, Andrew MacLeod <amacleod@redhat.com> wrote:
...
1 - One of the core themes in RABLE was very early selection of
instructions from patterns. RTL patterns are initially chosen by the
EXPAND pass. EXPAND tends to generates better rtl patterns by being
handed complex trees which it can process and get better combinations.
When TREE-SSA was first implemented, we got very poor RTL because
expand was seeing very small trees. TER (Temporary Expression
Replacement) was invented, which mashed any single-def/single-use
ssa_names together into more complex trees. This gave expand a better
chance of selecting better instructions, and made a huge difference.
Have you considered using BURG/IBURG style tree pattern matching
instruction selection ?
http://www.cs.princeton.edu/software/iburg/
That approach can certainly provide a low register pressure
high quality instruction selection.
--
#pragma ident "Seongbae Park, compiler, http://seongbae.blogspot.com";