[Bug bootstrap/52287] [4.7 regression] ICE in ready_remove_first, at haifa-sched.c:1927

["bernds at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52287

--- Comment #9 from Bernd Schmidt <bernds at gcc dot gnu.org> 2012-02-23 15:41:49 UTC ---
(In reply to comment #8)
> This reproduces only on Solaris 8 because the sort of the ready list isn't
> stable in the presence of debug insns, given that rank_for_schedule isn't
> anti-symmetrical:

Thanks for investigating this.

> Index: haifa-sched.c
> ===================================================================
> --- haifa-sched.c       (revision 184352)
> +++ haifa-sched.c       (working copy)
> @@ -1647,7 +1647,7 @@ rank_for_schedule (const void *x, const
>        /* Schedule debug insns as early as possible.  */
>        if (DEBUG_INSN_P (tmp) && !DEBUG_INSN_P (tmp2))
>         return -1;
> -      else if (DEBUG_INSN_P (tmp2))
> +      else if (DEBUG_INSN_P (tmp2) && !DEBUG_INSN_P (tmp))
>         return 1;
>      }
> 
> as it makes the sort stable and equivalent to the non-Solaris 8 case.

Almost OK, but in the case of two debug insns, can you make it return the
difference of the INSN_UIDs here? I'd rather not fall through into the other
code for DEBUG_INSNs.

Such a patch is preapproved.