re PR c++/51868 (Crash when generating the move constructor for a class with a bit field)

	PR c++/51868
	* typeck.c (build_static_cast_1): Handle bit-fields properly.

From-SVN: r183218

gcc/cp/ChangeLog

+2012-01-16  Jason Merrill  <jason@redhat.com>
+
+	PR c++/51868
+	* typeck.c (build_static_cast_1): Handle bit-fields properly.
+
 2012-01-13  Ian Lance Taylor  <iant@google.com>
 
 	PR c++/50012

gcc/cp/typeck.c

@@ -5812,11 +5812,12 @@ build_static_cast_1 (tree type, tree expr, bool c_cast_p,
 {
   tree intype;
   tree result;
+  cp_lvalue_kind clk;
 
   /* Assume the cast is valid.  */
   *valid_p = true;
 
-  intype = TREE_TYPE (expr);
+  intype = unlowered_expr_type (expr);
 
   /* Save casted types in the function's used types hash table.  */
   used_types_insert (type);
@@ -5882,13 +5883,16 @@ build_static_cast_1 (tree type, tree expr, bool c_cast_p,
      cv2 T2 if cv2 T2 is reference-compatible with cv1 T1 (8.5.3)."  */
   if (TREE_CODE (type) == REFERENCE_TYPE
       && TYPE_REF_IS_RVALUE (type)
-      && real_lvalue_p (expr)
+      && (clk = real_lvalue_p (expr))
       && reference_related_p (TREE_TYPE (type), intype)
       && (c_cast_p || at_least_as_qualified_p (TREE_TYPE (type), intype)))
     {
-      /* Handle the lvalue case here by casting to lvalue reference and
-	 then changing it to an rvalue reference.  Casting an xvalue to
-	 rvalue reference will be handled by the main code path.  */
+      if (clk == clk_ordinary)
+	{
+	  /* Handle the (non-bit-field) lvalue case here by casting to
+	     lvalue reference and then changing it to an rvalue reference.
+	     Casting an xvalue to rvalue reference will be handled by the
+	     main code path.  */
 	  tree lref = cp_build_reference_type (TREE_TYPE (type), false);
 	  result = (perform_direct_initialization_if_possible
 		    (lref, expr, c_cast_p, complain));
@@ -5899,6 +5903,10 @@ build_static_cast_1 (tree type, tree expr, bool c_cast_p,
 	    result = build1 (NON_LVALUE_EXPR, type, result);
 	  return convert_from_reference (result);
 	}
+      else
+	/* For a bit-field or packed field, bind to a temporary.  */
+	expr = rvalue (expr);
+    }
 
   /* Resolve overloaded address here rather than once in
      implicit_conversion and again in the inverse code below.  */

gcc/testsuite/ChangeLog

+2012-01-16  Jason Merrill  <jason@redhat.com>
+
+	PR c++/51868
+	* g++.dg/cpp0x/rv-bitfield.C: New.
+	* g++.dg/cpp0x/rv-bitfield2.C: New.
+
 2012-01-16  Paul Thomas  <pault@gcc.gnu.org>
 
 	* gfortran.dg/class_array_3.f03: Remove the explicit loop in

gcc/testsuite/g++.dg/cpp0x/rv-bitfield.C

+// { dg-options -std=c++0x }
+
+struct A
+{
+  int i : 1;
+};
+
+int main()
+{
+  A a;
+  static_cast<int&&>(a.i);
+}

gcc/testsuite/g++.dg/cpp0x/rv-bitfield2.C

+// PR c++/51868
+// { dg-options -std=c++0x }
+
+struct A {
+  A() {}
+  A(const A&) {}
+  A(A&&) {}
+};
+
+struct B {
+  A a;
+  int f : 1;
+};
+
+B func() {
+  return B();
+}