tree-sra.c (replace_uses_with_default_def_ssa_name): New function.

2010-04-13  Martin Jambor  <mjambor@suse.cz>

	* tree-sra.c (replace_uses_with_default_def_ssa_name): New function.
	(sra_modify_assign): Delete stmts loading dead data even if racc has no
	children.  Call replace_uses_with_default_def_ssa_name to handle
	SSA_NAES on lhs.

	* testsuite/gcc.dg/tree-ssa/sra-9.c: New test.

From-SVN: r158271

gcc/ChangeLog

+2010-04-13  Martin Jambor  <mjambor@suse.cz>
+
+	* tree-sra.c (replace_uses_with_default_def_ssa_name): New function.
+	(sra_modify_assign): Delete stmts loading dead data even if racc has no
+	children.  Call replace_uses_with_default_def_ssa_name to handle
+	SSA_NAES on lhs.
+
 2010-04-13  Michael Matz  <matz@suse.de>
 
 	PR middle-end/43730

gcc/testsuite/ChangeLog

+2010-04-13  Martin Jambor  <mjambor@suse.cz>
+
+	* gcc.dg/tree-ssa/sra-9.c: New test.
+
 2010-04-13  Michael Matz  <matz@suse.de>
 
 	PR middle-end/43730

gcc/testsuite/gcc.dg/tree-ssa/sra-9.c

+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-optimized" } */
+
+struct S
+{
+  int a, b, c;
+  int z[20];
+};
+
+int foo (int d)
+{
+  struct S s;
+
+  s.a = d;
+  return s.a + s.b;
+}
+
+/* There should be no reference to s.b.  */
+/* { dg-final { scan-tree-dump-times "s\.b" 0 "optimized"} } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */

gcc/tree-sra.c

@@ -2528,6 +2528,37 @@ sra_modify_constructor_assign (gimple *stmt, gimple_stmt_iterator *gsi)
     }
 }
 
+/* Create a new suitable default definition SSA_NAME and replace all uses of
+   SSA with it.  */
+
+static void
+replace_uses_with_default_def_ssa_name (tree ssa)
+{
+  tree repl, decl = SSA_NAME_VAR (ssa);
+  if (TREE_CODE (decl) == PARM_DECL)
+    {
+      tree tmp = create_tmp_var (TREE_TYPE (decl), "SR");
+      if (TREE_CODE (TREE_TYPE (tmp)) == COMPLEX_TYPE
+	  || TREE_CODE (TREE_TYPE (tmp)) == VECTOR_TYPE)
+	DECL_GIMPLE_REG_P (tmp) = 1;
+
+      get_var_ann (tmp);
+      add_referenced_var (tmp);
+      repl = make_ssa_name (tmp, gimple_build_nop ());
+      set_default_def (tmp, repl);
+    }
+  else
+    {
+      repl = gimple_default_def (cfun, decl);
+      if (!repl)
+	{
+	  repl = make_ssa_name (decl, gimple_build_nop ());
+	  set_default_def (decl, repl);
+	}
+    }
+
+  replace_uses_by (ssa, repl);
+}
 
 /* Callback of scan_function to process assign statements.  It examines both
    sides of the statement, replaces them with a scalare replacement if there is
@@ -2703,26 +2734,28 @@ sra_modify_assign (gimple *stmt, gimple_stmt_iterator *gsi,
 	}
       else
 	{
-	  if (access_has_children_p (racc))
+	  if (racc)
 	    {
-	      if (!racc->grp_unscalarized_data
-		  /* Do not remove SSA name definitions (PR 42704).  */
-		  && TREE_CODE (lhs) != SSA_NAME)
+	      if (!racc->grp_to_be_replaced && !racc->grp_unscalarized_data)
 		{
-		  generate_subtree_copies (racc->first_child, lhs,
-					   racc->offset, 0, 0, gsi,
-					   false, false);
+		  if (racc->first_child)
+		    generate_subtree_copies (racc->first_child, lhs,
+					     racc->offset, 0, 0, gsi,
+					     false, false);
 		  gcc_assert (*stmt == gsi_stmt (*gsi));
+		  if (TREE_CODE (lhs) == SSA_NAME)
+		    replace_uses_with_default_def_ssa_name (lhs);
+
 		  unlink_stmt_vdef (*stmt);
 		  gsi_remove (gsi, true);
 		  sra_stats.deleted++;
 		  return SRA_SA_REMOVED;
 		}
-	      else
+	      else if (racc->first_child)
 		generate_subtree_copies (racc->first_child, lhs,
 					 racc->offset, 0, 0, gsi, false, true);
 	    }
-	  else if (access_has_children_p (lacc))
+	  if (access_has_children_p (lacc))
 	    generate_subtree_copies (lacc->first_child, rhs, lacc->offset,
 				     0, 0, gsi, true, true);
 	}