re PR middle-end/53790 (ICE on dereferencing a extern union in asm statement)

2012-06-28  Richard Guenther  <rguenther@suse.de>

	PR middle-end/53790
	* expr.c (expand_expr_real_1): Verify if the type is complete
	before inspecting its size.

	* gcc.dg/torture/pr53790.c: New testcase.

From-SVN: r189045

gcc/ChangeLog

+2012-06-28  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/53790
+	* expr.c (expand_expr_real_1): Verify if the type is complete
+	before inspecting its size.
+
 2012-06-28  Andreas Schwab  <schwab@linux-m68k.org>
 
 	* doc/include/gpl.texi: Remove.

gcc/expr.c

@@ -9832,6 +9832,7 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode,
 	orig_op0 = op0
 	  = expand_expr (tem,
 			 (TREE_CODE (TREE_TYPE (tem)) == UNION_TYPE
+			  && COMPLETE_TYPE_P (TREE_TYPE (tem))
 			  && (TREE_CODE (TYPE_SIZE (TREE_TYPE (tem)))
 			      != INTEGER_CST)
 			  && modifier != EXPAND_STACK_PARM

gcc/testsuite/ChangeLog

+2012-06-28  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/53790
+	* gcc.dg/torture/pr53790.c: New testcase.
+
 2012-06-28  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/53645

gcc/testsuite/gcc.dg/torture/pr53790.c

+/* { dg-do compile } */
+
+typedef struct s {
+    int value;
+} s_t;
+
+static inline int 
+read(s_t const *var)
+{
+  return var->value;
+}
+
+int main()
+{
+  extern union u extern_var;
+  return read((s_t *)&extern_var);
+}