re PR middle-end/42898 (volatile structures and compound literal initializers)

2010-01-31  Richard Guenther  <rguenther@suse.de>

	PR middle-end/42898
	* gimplify.c (gimplify_init_constructor): For volatile LHS
	initialize a temporary.

	* gcc.dg/torture/pr42898.c: New testcase.

From-SVN: r156404

gcc/ChangeLog

+2010-01-31  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/42898
+	* gimplify.c (gimplify_init_constructor): For volatile LHS
+	initialize a temporary.
+
 2010-01-31  Matthias Klose  <doko@ubuntu.com>
 
 	* configure.ac: Fix __stack_chk_fail check for cross builds configured

gcc/gimplify.c

@@ -3745,6 +3745,21 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
 	      }
 	  }
 
+	/* If the target is volatile and we have non-zero elements
+	   initialize the target from a temporary.  */
+	if (TREE_THIS_VOLATILE (object)
+	    && !TREE_ADDRESSABLE (type)
+	    && num_nonzero_elements > 0)
+	  {
+	    tree temp = create_tmp_var (TYPE_MAIN_VARIANT (type), NULL);
+	    TREE_OPERAND (*expr_p, 0) = temp;
+	    *expr_p = build2 (COMPOUND_EXPR, TREE_TYPE (*expr_p),
+			      *expr_p,
+			      build2 (MODIFY_EXPR, void_type_node,
+				      object, temp));
+	    return GS_OK;
+	  }
+
 	if (notify_temp_creation)
 	  return GS_OK;
 

gcc/testsuite/ChangeLog

+2010-01-31  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/42898
+	* gcc.dg/torture/pr42898.c: New testcase.
+
 2010-01-31  Paul Thomas  <pault@gcc.gnu.org>
 
         PR fortran/38324

gcc/testsuite/gcc.dg/torture/pr42898.c

+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-optimized" } */
+
+struct hardware {
+  int parm1:8;
+  int :4;
+  int parm2:4;
+  int parm3:15;
+  int parm4:1;
+};
+
+void f1(volatile struct hardware *ptr)
+{
+  *ptr=(struct hardware) {
+    .parm1=42,
+    .parm2=13,
+    .parm3=11850,
+    .parm4=1,
+  };
+}
+
+/* { dg-final { scan-tree-dump-times "\\*ptr" 1 "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */