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Problem with patch for PR tree-optimization/29789
- From: Steve Ellcey <sje at cup dot hp dot com>
- To: richard dot guenther at gmail dot com
- Cc: gcc at gcc dot gnu dot org
- Date: Wed, 25 Apr 2007 13:55:14 -0700 (PDT)
- Subject: Problem with patch for PR tree-optimization/29789
- Reply-to: sje at cup dot hp dot com
Richard,
Has anyone reported any problems with your tree-ssa-loop-im.c patch that
fixes PR tree-optimization/29789? I have been looking at a failure with
the SPECfp2000 173.applu test. I found that if I compile it with
version r124041 of the GCC gfortran compiler it works but if I compile
it with version r124042 it fails. The difference between the two is
your checkin:
2007-04-22 Richard Guenther <rguenther@suse.de>
PR tree-optimization/29789
* tree-ssa-loop-im.c (stmt_cost): Adjust cost of shifts.
(rewrite_reciprocal): New helper split out from
determine_invariantness_stmt.
(rewrite_bittest): Likewise.
(determine_invariantness_stmt): Rewrite (A >> B) & 1 to
A & (1 << B) if (1 << B) is loop invariant but (A >> B)
is not.
To make things harder, the problem only seems to happen if I build
bootstrap. If I build a non-bootstrap compiler then the applu test
compiles and runs fine. If I build a bootstrap compiler, I can compile
applu but the program core dumps when run. Do you have any ideas about
what might be happening or what I might try in order to understand what
is going wrong.
Steve Ellcey
sje@cup.hp.com