Re: [RFA] expand from SSA form (1/2)

[Michael Matz <matz at suse dot de>]

Hi,

On Sun, 26 Apr 2009, Michael Matz wrote:

> > > + Â if (SA.values
> > > + Â Â Â && TREE_CODE (lhs) == SSA_NAME
> > > + Â Â Â && SA.values[SSA_NAME_VERSION (lhs)])
> > > + Â Â lhs = gimple_assign_rhs_to_tree (SA.values[SSA_NAME_VERSION (lhs)]);
> > 
> > Do we really need the SA.values array here?  It seems that
> > a bitmap would be enough, as the definition should be still
> > reachable via SSA_NAME_DEF_STMT (lhs).  (Thanks Paolo
> > for noticing this)
> 
> This should indeed be possible, but I want to do this as cleanup next 
> week.

Like so.  Already regstrapped without regressions on x86_64-linux.  
Committed as r146837.


Ciao,
Michael.
-- 
	* ssaexpand.h (struct ssaexpand): Member 'values' is a bitmap.
	(get_gimple_for_ssa_name): Adjust, lookup using SSA_NAME_DEF_STMT.
	* tree-ssa-live.h: (find_replaceable_exprs): Return a bitmap.
	(dump_replaceable_exprs): Take a bitmap.
	* cfgexpand.c (gimple_cond_pred_to_tree): Handle bitmap instead of
	array.
	(expand_gimple_basic_block): Likewise.
	* tree-ssa-ter.c (struct temp_expr_table_d): Make
	replaceable_expressions member a bitmap.
	(free_temp_expr_table): Pass back and deal with bitmap, not gimple*.
	(mark_replaceable): Likewise.
	(find_replaceable_in_bb, dump_replaceable_exprs): Likewise.
	* tree-outof-ssa.c (remove_ssa_form): 'values' is a bitmap.

Index: cfgexpand.c
===================================================================
--- cfgexpand.c	(Revision 146817)
+++ cfgexpand.c	(Arbeitskopie)
@@ -94,8 +94,8 @@ gimple_cond_pred_to_tree (gimple stmt)
   tree lhs = gimple_cond_lhs (stmt);
   if (SA.values
       && TREE_CODE (lhs) == SSA_NAME
-      && SA.values[SSA_NAME_VERSION (lhs)])
-    lhs = gimple_assign_rhs_to_tree (SA.values[SSA_NAME_VERSION (lhs)]);
+      && bitmap_bit_p (SA.values, SSA_NAME_VERSION (lhs)))
+    lhs = gimple_assign_rhs_to_tree (SSA_NAME_DEF_STMT (lhs));
 
   return build2 (gimple_cond_code (stmt), boolean_type_node,
 		 lhs, gimple_cond_rhs (stmt));
@@ -2078,7 +2078,8 @@ expand_gimple_basic_block (basic_block b
 		  /* Ignore this stmt if it is in the list of
 		     replaceable expressions.  */
 		  if (SA.values
-		      && SA.values[SSA_NAME_VERSION (DEF_FROM_PTR (def_p))])
+		      && bitmap_bit_p (SA.values, 
+				       SSA_NAME_VERSION (DEF_FROM_PTR (def_p))))
 		    continue;
 		}
 	      stmt_tree = gimple_to_tree (stmt);
Index: tree-ssa-live.h
===================================================================
--- tree-ssa-live.h	(Revision 146817)
+++ tree-ssa-live.h	(Arbeitskopie)
@@ -340,8 +340,8 @@ extern var_map coalesce_ssa_name (void);
 
 
 /* From tree-ssa-ter.c  */
-extern gimple *find_replaceable_exprs (var_map);
-extern void dump_replaceable_exprs (FILE *, gimple *);
+extern bitmap find_replaceable_exprs (var_map);
+extern void dump_replaceable_exprs (FILE *, bitmap);
 
 
 #endif /* _TREE_SSA_LIVE_H  */
Index: tree-ssa-ter.c
===================================================================
--- tree-ssa-ter.c	(Revision 146815)
+++ tree-ssa-ter.c	(Arbeitskopie)
@@ -159,7 +159,7 @@ typedef struct temp_expr_table_d
 {
   var_map map;
   bitmap *partition_dependencies;	/* Partitions expr is dependent on.  */
-  gimple *replaceable_expressions;	/* Replacement expression table.  */
+  bitmap replaceable_expressions;	/* Replacement expression table.  */
   bitmap *expr_decl_uids;		/* Base uids of exprs.  */
   bitmap *kill_list;			/* Expr's killed by a partition.  */
   int virtual_partition;		/* Pseudo partition for virtual ops.  */
@@ -216,10 +216,10 @@ new_temp_expr_table (var_map map)
 /* Free TER table T.  If there are valid replacements, return the expression 
    vector.  */
 
-static gimple *
+static bitmap
 free_temp_expr_table (temp_expr_table_p t)
 {
-  gimple *ret = NULL;
+  bitmap ret = NULL;
 
 #ifdef ENABLE_CHECKING
   unsigned x;
@@ -255,7 +255,7 @@ version_to_be_replaced_p (temp_expr_tabl
 {
   if (!tab->replaceable_expressions)
     return false;
-  return tab->replaceable_expressions[version] != NULL;
+  return bitmap_bit_p (tab->replaceable_expressions, version);
 }
 
 
@@ -562,8 +562,8 @@ mark_replaceable (temp_expr_table_p tab,
 
   /* Set the replaceable expression.  */
   if (!tab->replaceable_expressions)
-    tab->replaceable_expressions = XCNEWVEC (gimple, num_ssa_names + 1);
-  tab->replaceable_expressions[version] = SSA_NAME_DEF_STMT (var);
+    tab->replaceable_expressions = BITMAP_ALLOC (NULL);
+  bitmap_set_bit (tab->replaceable_expressions, version);
 }
 
 
@@ -653,12 +653,12 @@ find_replaceable_in_bb (temp_expr_table_
    NULL is returned by the function, otherwise an expression vector indexed
    by SSA_NAME version numbers.  */
 
-extern gimple *
+extern bitmap
 find_replaceable_exprs (var_map map)
 {
   basic_block bb;
   temp_expr_table_p table;
-  gimple *ret;
+  bitmap ret;
 
   table = new_temp_expr_table (map);
   FOR_EACH_BB (bb)
@@ -676,19 +676,19 @@ find_replaceable_exprs (var_map map)
 /* Dump TER expression table EXPR to file F.  */
 
 void
-dump_replaceable_exprs (FILE *f, gimple *expr)
+dump_replaceable_exprs (FILE *f, bitmap expr)
 {
   tree var;
   unsigned x;
 
   fprintf (f, "\nReplacing Expressions\n");
   for (x = 0; x < num_ssa_names; x++)
-    if (expr[x])
+    if (bitmap_bit_p (expr, x))
       {
 	var = ssa_name (x);
 	print_generic_expr (f, var, TDF_SLIM);
 	fprintf (f, " replace with --> ");
-	print_gimple_stmt (f, expr[x], 0, TDF_SLIM);
+	print_gimple_stmt (f, SSA_NAME_DEF_STMT (var), 0, TDF_SLIM);
 	fprintf (f, "\n");
       }
   fprintf (f, "\n");
Index: tree-outof-ssa.c
===================================================================
--- tree-outof-ssa.c	(Revision 146817)
+++ tree-outof-ssa.c	(Arbeitskopie)
@@ -791,7 +791,7 @@ expand_phi_nodes (struct ssaexpand *sa)
 static void
 remove_ssa_form (bool perform_ter, struct ssaexpand *sa)
 {
-  gimple *values = NULL;
+  bitmap values = NULL;
   var_map map;
   unsigned i;
 
@@ -926,7 +926,7 @@ finish_out_of_ssa (struct ssaexpand *sa)
 {
   free (sa->partition_to_pseudo);
   if (sa->values)
-    free (sa->values);
+    BITMAP_FREE (sa->values);
   delete_var_map (sa->map);
   BITMAP_FREE (sa->partition_has_default_def);
   memset (sa, 0, sizeof *sa);
Index: ssaexpand.h
===================================================================
--- ssaexpand.h	(Revision 146817)
+++ ssaexpand.h	(Arbeitskopie)
@@ -31,10 +31,9 @@ struct ssaexpand
   /* The computed partitions of SSA names are stored here.  */
   var_map map;
 
-  /* For a SSA name version V values[V] contains the gimple statement
-     defining it iff TER decided that it should be forwarded, NULL
-     otherwise.  */
-  gimple *values;
+  /* For an SSA name version V bit V is set iff TER decided that
+     its definition should be forwarded.  */
+  bitmap values;
 
   /* For a partition number I partition_to_pseudo[I] contains the
      RTL expression of the allocated space of it (either a MEM or
@@ -67,8 +66,8 @@ static inline gimple
 get_gimple_for_ssa_name (tree exp)
 {
   int v = SSA_NAME_VERSION (exp);
-  if (SA.values)
-    return SA.values[v];
+  if (SA.values && bitmap_bit_p (SA.values, v))
+    return SSA_NAME_DEF_STMT (exp);
   return NULL;
 }