tree-dfa.c (free_df_for_stmt): No longer static.

	* tree-dfa.c (free_df_for_stmt): No longer static.
	(free_df): Update comments.
	* tree-flow.h (free_df_for_stmt): Prototype.
	* tree-ssa-dse.c (dse_optimize_stmt): Call free_df_for_stmt.  Also
	call release_defs.

From-SVN: r87531

gcc/ChangeLog

+2004-09-14 Jeff Law  <law@redhat.com>
+
+	* tree-dfa.c (free_df_for_stmt): No longer static.
+	(free_df): Update comments.
+	* tree-flow.h (free_df_for_stmt): Prototype.
+	* tree-ssa-dse.c (dse_optimize_stmt): Call free_df_for_stmt.  Also
+	call release_defs.
+
 2004-09-14  Diego Novillo  <dnovillo@redhat.com>
 
 	PR tree-optimization/17252

gcc/tree-dfa.c

@@ -188,9 +188,9 @@ compute_immediate_uses (int flags, bool (*calc_for)(tree))
 }
 
 
-/* Invalidates dataflow information for a statement STMT.  */
+/* Invalidates dataflow information for a statement STMT.   */
 
-static void
+void
 free_df_for_stmt (tree stmt)
 {
   dataflow_t *df;
@@ -221,7 +221,13 @@ free_df_for_stmt (tree stmt)
 }
 
 
-/* Invalidate dataflow information for the whole function.  */
+/* Invalidate dataflow information for the whole function. 
+
+   Note this only invalidates dataflow information on statements and
+   PHI nodes which are reachable.
+
+   A deleted statement may still have attached dataflow information
+   on it.  */
 
 void
 free_df (void)

gcc/tree-flow.h

@@ -530,6 +530,7 @@ extern void dump_immediate_uses_for (FILE *, tree);
 extern void debug_immediate_uses_for (tree);
 extern void compute_immediate_uses (int, bool (*)(tree));
 extern void free_df (void);
+extern void free_df_for_stmt (tree);
 extern tree get_virtual_var (tree);
 extern void add_referenced_tmp_var (tree var);
 extern void mark_new_vars_to_rename (tree, bitmap);

gcc/tree-ssa-dse.c

@@ -326,6 +326,14 @@ dse_optimize_stmt (struct dom_walk_data *walk_data,
 	     This allows us to cascade dead stores.  */
 	  redirect_immediate_uses (stmt, skipped_phi ? skipped_phi : use);
 
+	  /* Be sure to remove any dataflow information attached to
+	     this statement.  */
+	  free_df_for_stmt (stmt);
+
+	  /* And release any SSA_NAMEs set in this statement back to the
+	     SSA_NAME manager.  */
+	  release_defs (stmt);
+
 	  /* Finally remove the dead store.  */
 	  bsi_remove (&bsi);
 	}