[Bug debug/61923] [4.8/4.9/4.10 Regression] -fcompare-debug errors while building Linux kernel.

[vmakarov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61923

--- Comment #5 from Vladimir Makarov <vmakarov at gcc dot gnu.org> ---
The difference after scheduling a block is in DFA state because of additional
advance_one_cycle call when debug_insns are present.

The situation looks like

                                         -g
      last bb insn                  last real bb insn
        -> advance_one_cycle          ->advance_one_cycle
                                    debug_insn
                                      ->advance_one_cycle

Last advance cycle is done at the end of processing all bb insns.

I'll try to produce a patch tomorrow to fix it which is not easy as
schedule_block is now very complicated function working in many modes and
containing a lot of gotos.