Re: [1/4] SMS: remove register undo list

Re: [1/4] SMS: remove register undo list

[Ayal Zaks]

Resending; didn't seem to go through.

---------- Forwarded message ----------
From: Ayal Zaks <ayal.zaks@gmail.com>
Date: 2011/9/11
Subject: gcc-patches@gcc.gnu.org
To: Richard Sandiford ‫richard.sandiford@linaro.org‬


 Richard Sandiford <richard.sandiford@linaro.org> wrote on 30/08/2011
02:58:22 PM:

> From: Richard Sandiford <richard.sandiford@linaro.org>

> To: gcc-patches@gcc.gnu.org

> Cc: Ayal Zaks/Haifa/IBM@IBMIL

> Date: 30/08/2011 02:58 PM

> Subject: [1/4] SMS: remove register undo list

>
> This patch removes the (unused) undo_replace_buff_elem list.
> Verges on the obvious, but still.

Sure, this is fine.

Thanks for the clean-up,

Ayal.

>
> Patch 3 splits the generation of moves into two: one function to record
> what needs to happen, and another function to actually do it. It's then
> easy to bail out if we decide that we don't want the moves.
>
> Richard
>
>
> gcc/
> * modulo-sched.c (undo_replace_buff_elem): Delete.
> (generate_reg_moves): Don't build and return an undo list.
> (free_undo_replace_buff): Delete.
> (sms_schedule): Adjust call to generate_reg_moves.
> Don't call free_undo_replace_buff.
>
> Index: gcc/modulo-sched.c
> ===================================================================
> --- gcc/modulo-sched.c 2011-08-24 12:38:37.171362916 +0100
> +++ gcc/modulo-sched.c 2011-08-24 12:56:17.754942951 +0100
> @@ -165,17 +165,6 @@ struct partial_schedule
> int stage_count; /* The stage count of the partial schedule. */
> };
>
> -/* We use this to record all the register replacements we do in
> - the kernel so we can undo SMS if it is not profitable. */
> -struct undo_replace_buff_elem
> -{
> - rtx insn;
> - rtx orig_reg;
> - rtx new_reg;
> - struct undo_replace_buff_elem *next;
> -};
> -
> -
>
> static partial_schedule_ptr create_partial_schedule (int ii, ddg_ptr, int history);
> static void free_partial_schedule (partial_schedule_ptr);
> @@ -456,13 +445,12 @@ print_node_sched_params (FILE *file, int
> nreg_moves = ----------------------------------- + 1 - { dependence.
> ii { 1 if not.
> */
> -static struct undo_replace_buff_elem *
> +static void
> generate_reg_moves (partial_schedule_ptr ps, bool rescan)
> {
> ddg_ptr g = ps->g;
> int ii = ps->ii;
> int i;
> - struct undo_replace_buff_elem *reg_move_replaces = NULL;
>
> for (i = 0; i < g->num_nodes; i++)
> {
> @@ -543,22 +531,6 @@ generate_reg_moves (partial_schedule_ptr
>
> EXECUTE_IF_SET_IN_SBITMAP (uses_of_defs[i_reg_move], 0, i_use, sbi)
> {
> - struct undo_replace_buff_elem *rep;
> -
> - rep = (struct undo_replace_buff_elem *)
> - xcalloc (1, sizeof (struct undo_replace_buff_elem));
> - rep->insn = g->nodes[i_use].insn;
> - rep->orig_reg = old_reg;
> - rep->new_reg = new_reg;
> -
> - if (! reg_move_replaces)
> - reg_move_replaces = rep;
> - else
> - {
> - rep->next = reg_move_replaces;
> - reg_move_replaces = rep;
> - }
> -
> replace_rtx (g->nodes[i_use].insn, old_reg, new_reg);
> if (rescan)
> df_insn_rescan (g->nodes[i_use].insn);
> @@ -568,21 +540,6 @@ generate_reg_moves (partial_schedule_ptr
> }
> sbitmap_vector_free (uses_of_defs);
> }
> - return reg_move_replaces;
> -}
> -
> -/* Free memory allocated for the undo buffer. */
> -static void
> -free_undo_replace_buff (struct undo_replace_buff_elem *reg_move_replaces)
> -{
> -
> - while (reg_move_replaces)
> - {
> - struct undo_replace_buff_elem *rep = reg_move_replaces;
> -
> - reg_move_replaces = reg_move_replaces->next;
> - free (rep);
> - }
> }
>
> /* Update the sched_params (time, row and stage) for node U using the II,
> @@ -1472,8 +1429,6 @@ sms_schedule (void)
> }
> else
> {
> - struct undo_replace_buff_elem *reg_move_replaces;
> -
> if (!opt_sc_p)
> {
> /* Rotate the partial schedule to have the branch in row ii-1. */
> @@ -1523,13 +1478,11 @@ sms_schedule (void)
> /* The life-info is not valid any more. */
> df_set_bb_dirty (g->bb);
>
> - reg_move_replaces = generate_reg_moves (ps, true);
> + generate_reg_moves (ps, true);
> if (dump_file)
> print_node_sched_params (dump_file, g->num_nodes, g);
> /* Generate prolog and epilog. */
> generate_prolog_epilog (ps, loop, count_reg, count_init);
> -
> - free_undo_replace_buff (reg_move_replaces);
> }
>
> free_partial_schedule (ps);

[1/4] SMS: remove register undo list

[Richard Sandiford]

This patch removes the (unused) undo_replace_buff_elem list.
Verges on the obvious, but still.

Patch 3 splits the generation of moves into two: one function to record
what needs to happen, and another function to actually do it.  It's then
easy to bail out if we decide that we don't want the moves.

Richard


gcc/
	* modulo-sched.c (undo_replace_buff_elem): Delete.
	(generate_reg_moves): Don't build and return an undo list.
	(free_undo_replace_buff): Delete.
	(sms_schedule): Adjust call to generate_reg_moves.
	Don't call free_undo_replace_buff.

Index: gcc/modulo-sched.c
===================================================================
--- gcc/modulo-sched.c	2011-08-24 12:38:37.171362916 +0100
+++ gcc/modulo-sched.c	2011-08-24 12:56:17.754942951 +0100
@@ -165,17 +165,6 @@ struct partial_schedule
   int stage_count;  /* The stage count of the partial schedule.  */
 };
 
-/* We use this to record all the register replacements we do in
-   the kernel so we can undo SMS if it is not profitable.  */
-struct undo_replace_buff_elem
-{
-  rtx insn;
-  rtx orig_reg;
-  rtx new_reg;
-  struct undo_replace_buff_elem *next;
-};
-
-
 
 static partial_schedule_ptr create_partial_schedule (int ii, ddg_ptr, int history);
 static void free_partial_schedule (partial_schedule_ptr);
@@ -456,13 +445,12 @@ print_node_sched_params (FILE *file, int
    nreg_moves = ----------------------------------- + 1 - {   dependence.
                             ii                          { 1 if not.
 */
-static struct undo_replace_buff_elem *
+static void
 generate_reg_moves (partial_schedule_ptr ps, bool rescan)
 {
   ddg_ptr g = ps->g;
   int ii = ps->ii;
   int i;
-  struct undo_replace_buff_elem *reg_move_replaces = NULL;
 
   for (i = 0; i < g->num_nodes; i++)
     {
@@ -543,22 +531,6 @@ generate_reg_moves (partial_schedule_ptr
 
 	  EXECUTE_IF_SET_IN_SBITMAP (uses_of_defs[i_reg_move], 0, i_use, sbi)
 	    {
-	      struct undo_replace_buff_elem *rep;
-
-	      rep = (struct undo_replace_buff_elem *)
-		    xcalloc (1, sizeof (struct undo_replace_buff_elem));
-	      rep->insn = g->nodes[i_use].insn;
-	      rep->orig_reg = old_reg;
-	      rep->new_reg = new_reg;
-
-	      if (! reg_move_replaces)
-		reg_move_replaces = rep;
-	      else
-		{
-		  rep->next = reg_move_replaces;
-		  reg_move_replaces = rep;
-		}
-
 	      replace_rtx (g->nodes[i_use].insn, old_reg, new_reg);
 	      if (rescan)
 		df_insn_rescan (g->nodes[i_use].insn);
@@ -568,21 +540,6 @@ generate_reg_moves (partial_schedule_ptr
 	}
       sbitmap_vector_free (uses_of_defs);
     }
-  return reg_move_replaces;
-}
-
-/* Free memory allocated for the undo buffer.  */
-static void
-free_undo_replace_buff (struct undo_replace_buff_elem *reg_move_replaces)
-{
-
-  while (reg_move_replaces)
-    {
-      struct undo_replace_buff_elem *rep = reg_move_replaces;
-
-      reg_move_replaces = reg_move_replaces->next;
-      free (rep);
-    }
 }
 
 /* Update the sched_params (time, row and stage) for node U using the II,
@@ -1472,8 +1429,6 @@ sms_schedule (void)
 	}
       else
 	{
-	  struct undo_replace_buff_elem *reg_move_replaces;
-
           if (!opt_sc_p)
             {
 	      /* Rotate the partial schedule to have the branch in row ii-1.  */
@@ -1523,13 +1478,11 @@ sms_schedule (void)
 	  /* The life-info is not valid any more.  */
 	  df_set_bb_dirty (g->bb);
 
-	  reg_move_replaces = generate_reg_moves (ps, true);
+	  generate_reg_moves (ps, true);
 	  if (dump_file)
 	    print_node_sched_params (dump_file, g->num_nodes, g);
 	  /* Generate prolog and epilog.  */
           generate_prolog_epilog (ps, loop, count_reg, count_init);
-
-	  free_undo_replace_buff (reg_move_replaces);
 	}
 
       free_partial_schedule (ps);