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[Bug middle-end/36099] [4.4 Regression] early loop unrolling pass prevents vectorization, SLP doesn't do its job
- From: "victork at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 29 Jul 2008 22:56:39 -0000
- Subject: [Bug middle-end/36099] [4.4 Regression] early loop unrolling pass prevents vectorization, SLP doesn't do its job
- References: <bug-36099-12313@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #6 from victork at gcc dot gnu dot org 2008-07-29 22:56 -------
I had a closer look into testcase in original bug report and it appears that
vectorizer fails on attempt to vectorize __builtin_cexpi ().
Regarding different behavior of vectorizer with -m32 and -m64 described in
comment #5. It appears that with -m32, the internal loop is not unrolled, and
thus is vectorized later. While with -m64 the internal loop gets completely
unrolled, so there is no chance to vectorize it later.
--
victork at gcc dot gnu dot org changed:
What |Removed |Added
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36099