> > I had a brief look at find_modifiable_mems, which seems to be the only kind
> > of
> > schedule-time dependency breaking that we do. I started writing some new
> > code
> > that would handle REG_ARGS_SIZE, but then considered that wasn't terribly
> > appropriate for stage4.
> >
> > So I've left off with just the dependency links between the insns. We'd
> > need
> > these for the schedule-time adjustments anyway, and with them in place the
> > scheduler does not re-order the insns in a way that causes problems.
> >
> > Testing for x86_64 has finished; i686 is nearly done. I suppose the only
> > question I have is if anyone disagrees that OUTPUT is incorrect as the
> > dependency type.
>From i386 perspective, this seems like resonable compromise for now.
I did some re-testing of scheduler recently for generic.
Call sequences is one of few places where scheduling matters (in addition to
tight loops), but I do not think we will lose measurable % of perofmrance by
disabling scheduling here.
Thanks!
Honza
> >
> >
> > r~
> >
>
> * combine-stack-adj.c: Revert r206943.
> * sched-int.h (struct deps_desc): Add last_args_size.
> * sched-deps.c (init_deps): Initialize it.
> (sched_analyze_insn): Add OUTPUT dependencies between insns that
> contain REG_ARGS_SIZE notes.
>
>
> diff --git a/gcc/combine-stack-adj.c b/gcc/combine-stack-adj.c
> index c591c60..69fd5ea 100644
> --- a/gcc/combine-stack-adj.c
> +++ b/gcc/combine-stack-adj.c
> @@ -567,7 +567,6 @@ combine_stack_adjustments_for_block (basic_block bb)
> && try_apply_stack_adjustment (insn, reflist, 0,
> -last_sp_adjust))
> {
> - rtx note;
> if (last2_sp_set)
> maybe_move_args_size_note (last2_sp_set, last_sp_set, false);
> else
> @@ -577,11 +576,6 @@ combine_stack_adjustments_for_block (basic_block bb)
> reflist = NULL;
> last_sp_set = NULL_RTX;
> last_sp_adjust = 0;
> - /* We no longer adjust stack size. Whoever adjusted it earlier
> - hopefully got the note right. */
> - note = find_reg_note (insn, REG_ARGS_SIZE, NULL_RTX);
> - if (note)
> - remove_note (insn, note);
> continue;
> }
> }
> diff --git a/gcc/sched-deps.c b/gcc/sched-deps.c
> index 7efc937..efc4223 100644
> --- a/gcc/sched-deps.c
> +++ b/gcc/sched-deps.c
> @@ -3470,6 +3470,15 @@ sched_analyze_insn (struct deps_desc *deps, rtx x, rtx
> insn)
> change_spec_dep_to_hard (sd_it);
> }
> }
> +
> + /* We do not yet have code to adjust REG_ARGS_SIZE, therefore we must
> + honor their original ordering. */
> + if (find_reg_note (insn, REG_ARGS_SIZE, NULL))
> + {
> + if (deps->last_args_size)
> + add_dependence (insn, deps->last_args_size, REG_DEP_OUTPUT);
> + deps->last_args_size = insn;
> + }
> }
>
> /* Return TRUE if INSN might not always return normally (e.g. call exit,
> @@ -3876,6 +3885,7 @@ init_deps (struct deps_desc *deps, bool lazy_reg_last)
> deps->sched_before_next_jump = 0;
> deps->in_post_call_group_p = not_post_call;
> deps->last_debug_insn = 0;
> + deps->last_args_size = 0;
> deps->last_reg_pending_barrier = NOT_A_BARRIER;
> deps->readonly = 0;
> }
> diff --git a/gcc/sched-int.h b/gcc/sched-int.h
> index 3b1106f..2cec624 100644
> --- a/gcc/sched-int.h
> +++ b/gcc/sched-int.h
> @@ -539,6 +539,9 @@ struct deps_desc
> /* The last debug insn we've seen. */
> rtx last_debug_insn;
>
> + /* The last insn bearing REG_ARGS_SIZE that we've seen. */
> + rtx last_args_size;
> +
> /* The maximum register number for the following arrays. Before reload
> this is max_reg_num; after reload it is FIRST_PSEUDO_REGISTER. */
> int max_reg;
