re PR c++/46160 (ICE with volatile structure and enum)

	PR c++/46160
	* cp-gimplify.c (cp_gimplify_expr): Drop volatile MEM_REFs
	on the RHS to avoid infinite recursion with gimplify_expr.

	* g++.dg/opt/empty2.C: New test.

From-SVN: r166372

gcc/cp/ChangeLog

+2010-11-05  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/46160
+	* cp-gimplify.c (cp_gimplify_expr): Drop volatile MEM_REFs
+	on the RHS to avoid infinite recursion with gimplify_expr.
+
 2010-11-05  Jason Merrill  <jason@redhat.com>
 
 	PR c++/46304

gcc/cp/cp-gimplify.c

@@ -595,6 +595,16 @@ cp_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 	    if (!TREE_SIDE_EFFECTS (op1)
 		|| (DECL_P (op1) && TREE_THIS_VOLATILE (op1)))
 	      *expr_p = op0;
+	    else if (TREE_CODE (op1) == MEM_REF
+		     && TREE_THIS_VOLATILE (op1))
+	      {
+		/* Similarly for volatile MEM_REFs on the RHS.  */
+		if (!TREE_SIDE_EFFECTS (TREE_OPERAND (op1, 0)))
+		  *expr_p = op0;
+		else
+		  *expr_p = build2 (COMPOUND_EXPR, TREE_TYPE (*expr_p),
+				    TREE_OPERAND (op1, 0), op0);
+	      }
 	    else
 	      *expr_p = build2 (COMPOUND_EXPR, TREE_TYPE (*expr_p),
 				op0, op1);

gcc/testsuite/ChangeLog

 2010-11-05  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/46160
+	* g++.dg/opt/empty2.C: New test.
+
 	PR target/45670
 	* gcc.target/i386/pr45670.c: New test.
 

gcc/testsuite/g++.dg/opt/empty2.C

+// PR c++/46160
+// { dg-do compile }
+
+struct S
+{
+  enum E { A };
+} s;
+volatile S t;
+
+void f (S::E);
+
+void
+g ()
+{
+  volatile S *p = &s;
+  f (p->A);
+  f (t.A);
+}