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[Bug tree-optimization/44183] Vectorizer may generate invalid memory access
- From: "hjl dot tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 20 May 2010 08:50:47 -0000
- Subject: [Bug tree-optimization/44183] Vectorizer may generate invalid memory access
- References: <bug-44183-682@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #2 from hjl dot tools at gmail dot com 2010-05-20 08:50 -------
(In reply to comment #1)
> Do you mean that extract_even implementation does something illegal with this
> last element? Misaligned load also accesses elements outside the array, but the
> problem is in extract_even?
Vectorizer generates
vect_var_.12_25 = M*vect_pb.7_23{misalignment: 32};
vect_var_.13_27 = M*vect_pb.7_26{misalignment: 32};
Those may read beyond the end of array. Vectorizer
should check that vect_pb.7_23/vect_pb.7_26 + vector
size < end of array.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44183