http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56935
--- Comment #4 from Yuri Rumyantsev <ysrumyan at gmail dot com> 2013-04-15 14:54:50 UTC --- Richard, both subq's are accessed the same cash line and it means that after 1st store tthe 2nd load will stall till finish updating data cash (this is not exact explanation but if you'd like I can find out more strong and correct definition of memory conflict). In result non-vectorizable code will run much slower adn we saw such slowdown on 253.perl from cpu2000.
