------- Comment #6 from sje at cup dot hp dot com 2008-05-23 15:02 ------- It looks like this is a bug in register renaming. register renaming is turned on by -floop-unroll. You can reproduce the bug using -frename-registers in place of -funroll-loops.
-- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35658