http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50176
--- Comment #14 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-01-30 16:06:03 UTC --- Created attachment 26517 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26517 patch I've tried to implement a hack for this in fwprop (debug insn updating for that not implemented yet), but it unfortunately doesn't work, as for the zero_extend load from QImode mem insn we need before reload_completed a CC mode clobber, so apply_change_group fails. No idea how should such a thing be handled before reload. Although there is an insn that doesn't need to clobber CC (movzbl for this testcase), that pattern isn't enabled until reload_completed.
