On Mon, 2010-02-22 at 13:11 -0800, Andrew Pinski wrote: > On Mon, Feb 22, 2010 at 1:06 PM, Janis Johnson <janis...@us.ibm.com> wrote: > > If you can reproduce the problem with a small, self-contained test then > > please file a bug report. It might be possible to issue a warning or > > to detect that the loop should not be vectorized. If not, maybe the > > compiler should disable vectorization for -fno-strict-aliasing. > > It is not an aliasing issue but an alignment issue. Anyways this is > most likely the same as > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43009 .
Yes, that's the problem I had in mind but I was thinking about an explicit cast to a pointer to more-aligned data in the function that has the vector loop. There's no way to warn about the undefined behavior when the cast is in a different source file. It's interesting that two reports of failure due to this same undefined behavior come so close together. Janis
