anyone can help on this question please? thanks
> From: blue_3...@hotmail.com
> To: gcc@gcc.gnu.org; maxim.kuvyr...@gmail.com
> Subject: dep question in sched-deps.c
> Date: Wed, 21 Mar 2012 01:17:07 +0000
>
>
> Hello,
>
> I am confused by following piece of code in sched-deps.c. My understanding is
> the last_pending_memory_flush only holds jumps, calls and memory write. So I
> think the two invocations of add_dependence should build true dependence, not
> anti.
>
>
>
> for (u = deps->last_pending_memory_flush; u; u = XEXP (u, 1))
> {
> if (! NON_FLUSH_JUMP_P (u))
> add_dependence (insn, XEXP (u, 0), REG_DEP_ANTI); <-----------------------
> else if (deps_may_trap_p (x))
> {
> if ((sched_deps_info->generate_spec_deps)
> && sel_sched_p () && (spec_info->mask & BEGIN_CONTROL))
> {
> ds_t ds = set_dep_weak (DEP_ANTI, BEGIN_CONTROL,
> MAX_DEP_WEAK);
> note_dep (XEXP (u, 0), ds);
> }
> else
> add_dependence (insn, XEXP (u, 0), REG_DEP_ANTI); <---------------------------
> }
> }
>
>
> also, can you explain following comments in sched-deps.c. I don't quite
> understand what is means and what NON_FLUSH_JUMP_KIND is for.
>
> /* In deps->last_pending_memory_flush marks JUMP_INSNs that weren't
> added to the list because of flush_pending_lists, stands just
> for itself and not for any other pending memory reads/writes. */
>
>
>
> I also need more dicussion about DEPS_LIST and INSN_LIST. Maxim once kindly
> explained to me,
> "DEPS_LIST is a super-set of INSN_LIST. I kept INSN_LIST-style dependencies
> to avoid overhead on targets that don't need additional features of
> DEPS_LIST. Now that I look back at it, I should have removed INSN_LIST-style
> dependencies; I still hope to find time and clean that up (remove support for
> INSN_LIST-style dependencies).". But it is still over my head. my question is
> what is INSN_list-style dependencies? what is the extra feature of DEPS_LIST
> as a super-set of INSN_list?
>
> thanks
