http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56826
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> 2013-04-04 11:41:03 UTC --- Ok, the bug is that 'ncopies' in vect_build_slp_tree is not computed correctly. I can trivially incrementally improve it but the ultimate fix is to delay the checks done for vectorizing SLP loads / stores to after the whole SLP tree is built and thus all types participating in the SLP are known and we can compute the final unroll factor (in vect_make_slp_decision). Thus, I'll push the trivial improvement for now, the real fix will follow a SLP tree build re-org I am planning for next week anyway.
