------- Comment #4 from rguenth at gcc dot gnu dot org 2010-01-08 11:52 ------- It just means that we shouldn't thread to the header but always to the latch block. Note that this restriction should probably be restricted to the threading before loop optimizations. Or the 1st jump threading should simply avoid to thread over backedges (equivalent to removing the 1st DOM pass - though there is interesting fallout regarding jump-threading / loop header copying pass ordering).
-- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42646
