[Bug rtl-optimization/57940] [PATCH] Rerun df_analyze after delete_unmarked_insns during DCE

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57940

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2013-07-20
                 CC|                            |ebotcazou at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> If delete_unmarked_insns deletes some insn, DF state might be
> out of date, and, regs_ever_live might contain unused registers till the end.

I presume this occurs after reload?

> Fixed by forcing regs_ever_live update and rerunning df_analyze () at
> fini_dce().

No, calling df_compute_regs_ever_live (true) is incorrect after reload, see the
comment in rest_of_handle_df_initialize.