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[Bug tree-optimization/37194] [4.3/4.4 Regression] Autovectorization of small constant iteration loop degrades performance
- From: "irar at il dot ibm dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 30 Dec 2008 14:57:01 -0000
- Subject: [Bug tree-optimization/37194] [4.3/4.4 Regression] Autovectorization of small constant iteration loop degrades performance
- References: <bug-37194-14936@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #7 from irar at il dot ibm dot com 2008-12-30 14:57 -------
(In reply to comment #6)
> t.i:3: note: Vectorization may not be profitable.
> why doesn't the cost model then disallow vectorization here?
This is misleading. It only means that there exists loop bound threshold either
defined by the user or calculated with the cost model. It does not mean that
the cost model's decision is that the vectorization is not profitable.
I am adding this to our cleanup todo list.
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37194