Re: [PATCH v3 3/8] Simplify handling of INSN_ and EXPR_LISTs in sched-rgn.cc

[Maxim Kuvyrkov <maxim.kuvyrkov@linaro.org>]

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Dear RTL maintainers,

Gently ping.  This patch adds a couple of new functions to lists.cc, which
then are used to simplify logic in the scheduler.  OK to merge?

On Wed, 22 Nov 2023 at 15:14, Maxim Kuvyrkov <maxim.kuvyrkov@linaro.org>
wrote:

> This patch simplifies logic behind deps_join(), which will be
> important for the upcoming improvements of sched-deps.cc logging.
>
> The only functional change is that when deps_join() is called with
> empty state for the 2nd argument, it will not reverse INSN_ and
> EXPR_LISTs in the 1st argument.  Before this patch the lists were
> reversed due to use of concat_*_LIST().  Now, with copy_*_LIST()
> used for this case, the lists will remain in the original order.
>
> gcc/ChangeLog:
>
>         * lists.cc (copy_EXPR_LIST, concat_EXPR_LIST): New functions.
>         * rtl.h (copy_EXPR_LIST, concat_EXPR_LIST): Declare.
>         * sched-rgn.cc (concat_insn_list, concat_expr_list): New helpers.
>         (concat_insn_mem_list): Simplify.
>         (deps_join): Update
> ---
>  gcc/lists.cc     | 30 +++++++++++++++++++++++++++-
>  gcc/rtl.h        |  4 +++-
>  gcc/sched-rgn.cc | 51 +++++++++++++++++++++++++++---------------------
>  3 files changed, 61 insertions(+), 24 deletions(-)
>
> diff --git a/gcc/lists.cc b/gcc/lists.cc
> index 2cdf37ad533..83e7bf32176 100644
> --- a/gcc/lists.cc
> +++ b/gcc/lists.cc
> @@ -160,6 +160,24 @@ free_INSN_LIST_list (rtx_insn_list **listp)
>    free_list ((rtx *)listp, &unused_insn_list);
>  }
>
> +/* Make a copy of the EXPR_LIST list LINK and return it.  */
> +rtx_expr_list *
> +copy_EXPR_LIST (rtx_expr_list *link)
> +{
> +  rtx_expr_list *new_queue;
> +  rtx_expr_list **pqueue = &new_queue;
> +
> +  for (; link; link = link->next ())
> +    {
> +      rtx x = link->element ();
> +      rtx_expr_list *newlink = alloc_EXPR_LIST (REG_NOTE_KIND (link), x,
> NULL);
> +      *pqueue = newlink;
> +      pqueue = (rtx_expr_list **)&XEXP (newlink, 1);
> +    }
> +  *pqueue = NULL;
> +  return new_queue;
> +}
> +
>  /* Make a copy of the INSN_LIST list LINK and return it.  */
>  rtx_insn_list *
>  copy_INSN_LIST (rtx_insn_list *link)
> @@ -178,12 +196,22 @@ copy_INSN_LIST (rtx_insn_list *link)
>    return new_queue;
>  }
>
> +/* Duplicate the EXPR_LIST elements of COPY and prepend them to OLD.  */
> +rtx_expr_list *
> +concat_EXPR_LIST (rtx_expr_list *copy, rtx_expr_list *old)
> +{
> +  rtx_expr_list *new_rtx = old;
> +  for (; copy; copy = copy->next ())
> +    new_rtx = alloc_EXPR_LIST (REG_NOTE_KIND (copy), copy->element (),
> new_rtx);
> +  return new_rtx;
> +}
> +
>  /* Duplicate the INSN_LIST elements of COPY and prepend them to OLD.  */
>  rtx_insn_list *
>  concat_INSN_LIST (rtx_insn_list *copy, rtx_insn_list *old)
>  {
>    rtx_insn_list *new_rtx = old;
> -  for (; copy ; copy = copy->next ())
> +  for (; copy; copy = copy->next ())
>      {
>        new_rtx = alloc_INSN_LIST (copy->insn (), new_rtx);
>        PUT_REG_NOTE_KIND (new_rtx, REG_NOTE_KIND (copy));
> diff --git a/gcc/rtl.h b/gcc/rtl.h
> index e4b6cc0dbb5..7e952d7cbeb 100644
> --- a/gcc/rtl.h
> +++ b/gcc/rtl.h
> @@ -3764,10 +3764,12 @@ extern void free_EXPR_LIST_list (rtx_expr_list **);
>  extern void free_INSN_LIST_list (rtx_insn_list **);
>  extern void free_EXPR_LIST_node (rtx);
>  extern void free_INSN_LIST_node (rtx);
> +extern rtx_expr_list *alloc_EXPR_LIST (int, rtx, rtx);
>  extern rtx_insn_list *alloc_INSN_LIST (rtx, rtx);
> +extern rtx_expr_list *copy_EXPR_LIST (rtx_expr_list *);
>  extern rtx_insn_list *copy_INSN_LIST (rtx_insn_list *);
> +extern rtx_expr_list *concat_EXPR_LIST (rtx_expr_list *, rtx_expr_list *);
>  extern rtx_insn_list *concat_INSN_LIST (rtx_insn_list *, rtx_insn_list *);
> -extern rtx_expr_list *alloc_EXPR_LIST (int, rtx, rtx);
>  extern void remove_free_INSN_LIST_elem (rtx_insn *, rtx_insn_list **);
>  extern rtx remove_list_elem (rtx, rtx *);
>  extern rtx_insn *remove_free_INSN_LIST_node (rtx_insn_list **);
> diff --git a/gcc/sched-rgn.cc b/gcc/sched-rgn.cc
> index e5964f54ead..da3ec0458ff 100644
> --- a/gcc/sched-rgn.cc
> +++ b/gcc/sched-rgn.cc
> @@ -2585,25 +2585,32 @@ add_branch_dependences (rtx_insn *head, rtx_insn
> *tail)
>
>  static class deps_desc *bb_deps;
>
> +/* Return a new insn_list with all the elements from the two input
> lists.  */
> +static rtx_insn_list *
> +concat_insn_list (rtx_insn_list *copy, rtx_insn_list *old)
> +{
> +  if (!old)
> +    return copy_INSN_LIST (copy);
> +  return concat_INSN_LIST (copy, old);
> +}
> +
> +/* Return a new expr_list with all the elements from the two input
> lists.  */
> +static rtx_expr_list *
> +concat_expr_list (rtx_expr_list *copy, rtx_expr_list *old)
> +{
> +  if (!old)
> +    return copy_EXPR_LIST (copy);
> +  return concat_EXPR_LIST (copy, old);
> +}
> +
>  static void
>  concat_insn_mem_list (rtx_insn_list *copy_insns,
>                       rtx_expr_list *copy_mems,
>                       rtx_insn_list **old_insns_p,
>                       rtx_expr_list **old_mems_p)
>  {
> -  rtx_insn_list *new_insns = *old_insns_p;
> -  rtx_expr_list *new_mems = *old_mems_p;
> -
> -  while (copy_insns)
> -    {
> -      new_insns = alloc_INSN_LIST (copy_insns->insn (), new_insns);
> -      new_mems = alloc_EXPR_LIST (VOIDmode, copy_mems->element (),
> new_mems);
> -      copy_insns = copy_insns->next ();
> -      copy_mems = copy_mems->next ();
> -    }
> -
> -  *old_insns_p = new_insns;
> -  *old_mems_p = new_mems;
> +  *old_insns_p = concat_insn_list (copy_insns, *old_insns_p);
> +  *old_mems_p = concat_expr_list (copy_mems, *old_mems_p);
>  }
>
>  /* Join PRED_DEPS to the SUCC_DEPS.  */
> @@ -2619,11 +2626,11 @@ deps_join (class deps_desc *succ_deps, class
> deps_desc *pred_deps)
>        struct deps_reg *pred_rl = &pred_deps->reg_last[reg];
>        struct deps_reg *succ_rl = &succ_deps->reg_last[reg];
>
> -      succ_rl->uses = concat_INSN_LIST (pred_rl->uses, succ_rl->uses);
> -      succ_rl->sets = concat_INSN_LIST (pred_rl->sets, succ_rl->sets);
> +      succ_rl->uses = concat_insn_list (pred_rl->uses, succ_rl->uses);
> +      succ_rl->sets = concat_insn_list (pred_rl->sets, succ_rl->sets);
>        succ_rl->implicit_sets
> -       = concat_INSN_LIST (pred_rl->implicit_sets,
> succ_rl->implicit_sets);
> -      succ_rl->clobbers = concat_INSN_LIST (pred_rl->clobbers,
> +       = concat_insn_list (pred_rl->implicit_sets,
> succ_rl->implicit_sets);
> +      succ_rl->clobbers = concat_insn_list (pred_rl->clobbers,
>                                              succ_rl->clobbers);
>        succ_rl->uses_length += pred_rl->uses_length;
>        succ_rl->clobbers_length += pred_rl->clobbers_length;
> @@ -2641,10 +2648,10 @@ deps_join (class deps_desc *succ_deps, class
> deps_desc *pred_deps)
>                          &succ_deps->pending_write_mems);
>
>    succ_deps->pending_jump_insns
> -    = concat_INSN_LIST (pred_deps->pending_jump_insns,
> +    = concat_insn_list (pred_deps->pending_jump_insns,
>                          succ_deps->pending_jump_insns);
>    succ_deps->last_pending_memory_flush
> -    = concat_INSN_LIST (pred_deps->last_pending_memory_flush,
> +    = concat_insn_list (pred_deps->last_pending_memory_flush,
>                          succ_deps->last_pending_memory_flush);
>
>    succ_deps->pending_read_list_length +=
> pred_deps->pending_read_list_length;
> @@ -2653,17 +2660,17 @@ deps_join (class deps_desc *succ_deps, class
> deps_desc *pred_deps)
>
>    /* last_function_call is inherited by successor.  */
>    succ_deps->last_function_call
> -    = concat_INSN_LIST (pred_deps->last_function_call,
> +    = concat_insn_list (pred_deps->last_function_call,
>                          succ_deps->last_function_call);
>
>    /* last_function_call_may_noreturn is inherited by successor.  */
>    succ_deps->last_function_call_may_noreturn
> -    = concat_INSN_LIST (pred_deps->last_function_call_may_noreturn,
> +    = concat_insn_list (pred_deps->last_function_call_may_noreturn,
>                          succ_deps->last_function_call_may_noreturn);
>
>    /* sched_before_next_call is inherited by successor.  */
>    succ_deps->sched_before_next_call
> -    = concat_INSN_LIST (pred_deps->sched_before_next_call,
> +    = concat_insn_list (pred_deps->sched_before_next_call,
>                          succ_deps->sched_before_next_call);
>  }
>
> --
> 2.34.1
>
>

-- 
Maxim Kuvyrkov
www.linaro.org