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RE: How to detect whether we're inside of a loop??
- From: "S. Bosscher" <S dot Bosscher at student dot tudelft dot nl>
- To: 'Jan Hubicka ' <jh at suse dot cz>,"'S. Bosscher '" <S dot Bosscher at student dot tudelft dot nl>
- Cc: ''Daniel Berlin ' ' <dberlin at dberlin dot org>,''Geoff Keating ' ' <geoffk at geoffk dot org>,"''Kaveh R. Ghazi ' '" <ghazi at caip dot rutgers dot edu>,"''gcc at gcc dot gnu dot org ' '" <gcc at gcc dot gnu dot org>
- Date: Wed, 09 Apr 2003 21:16:56 +0200
- Subject: RE: How to detect whether we're inside of a loop??
Jan Hubicka wrote:
> > Daniel Berlin wrote:
> > > On Wednesday, April 9, 2003, at 02:25 PM, Geoff Keating wrote:
> > > > Why don't you just use the support that GCC already has for
> > > > detecting the probability that a block will be executed?
> > >
> > > Because it's at the tree level he's talking about, not the RTL
> > > level.
> >
> > FWIW, once tree-ssa-vrp is implemented, you get branch
> > prediction with it for free. Would that help?
> Definitly :)
> We already do have branch prediction algorithm at RTL level. I
> would like to port it to tree-ssa as soon as we realize how to
> maintain the profile over RTL expansion....
Yes that would be nice. Already when I first posted the pointer to the
SSA-VRP paper to Diego, it was discussed that we should figure out a way to
bring branch predictions from trees to RTL. Diego said that he expected it
to be quite hard to do because RTL is so different from trees. He also
suggested that we could maybe use RTL NOTEs for it...
Greetz
Steven