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[Bug tree-optimization/23049] [4.1 Regression] ICE with -O3 -ftree-vectorize on 4.1.x
- From: "law at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 20 Sep 2005 15:11:55 -0000
- Subject: [Bug tree-optimization/23049] [4.1 Regression] ICE with -O3 -ftree-vectorize on 4.1.x
- References: <20050724142245.23049.drab@kepler.fjfi.cvut.cz>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From law at redhat dot com 2005-09-20 15:11 -------
Subject: Re: [4.1 Regression] ICE with -O3
-ftree-vectorize on 4.1.x
On Sun, 2005-09-18 at 15:59 +0000, steven at gcc dot gnu dot org wrote:
> ------- Additional Comments From steven at gcc dot gnu dot org 2005-09-18 15:59 -------
> Actually fold_stmt has nothing to do with it. It is fold (cached_lhs) in
> trhead_across_edge that is the problem here. Jeff, what do you think about
> this patch?
Presumably COND_EXPR on the RHS of a statement is the only special case
that we need to worry about. I can't immediately think of others.
Seems pretty reasonable, in the case were the COND_EXPR_COND does not
fold, you could safely set pre_fold_lhs to TREE_OPERAND (stmt, 1) which
would allow us to catch cases where the THEN/ELSE clauses of the
COND_EXPR are equivalent due to substitutions. But I doubt it's
terribly important.
You might use pre_fold_expr rather than pre_fold_lhs which is a little
confusing since we're looking at the RHS of a statement :-)
jeff
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23049