re PR c++/64701 (internal compiler error: unexpected expression ‘<statement>’ of kind do_stmt)

	PR c++/64701
	* constexpr.c (maybe_constant_value): Just hand back STATEMENT_LIST.

From-SVN: r220046

gcc/cp/ChangeLog

 2015-01-23  Jason Merrill  <jason@redhat.com>
 
+	PR c++/64701
+	* constexpr.c (maybe_constant_value): Just hand back STATEMENT_LIST.
+
 	PR c++/64727
 	* constexpr.c (cxx_eval_constant_expression): Allow for lvalue use
 	of CONST_DECL.

gcc/cp/constexpr.c

@@ -3454,8 +3454,18 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
       break;
 
     default:
-      internal_error ("unexpected expression %qE of kind %s", t,
-		      get_tree_code_name (TREE_CODE (t)));
+      if (STATEMENT_CODE_P (TREE_CODE (t)))
+	{
+	  /* This function doesn't know how to deal with pre-genericize
+	     statements; this can only happen with statement-expressions,
+	     so for now just fail.  */
+	  if (!ctx->quiet)
+	    error_at (EXPR_LOCATION (t),
+		      "statement is not a constant-expression");
+	}
+      else
+	internal_error ("unexpected expression %qE of kind %s", t,
+			get_tree_code_name (TREE_CODE (t)));
       *non_constant_p = true;
       break;
     }

gcc/testsuite/g++.dg/ext/stmtexpr17.C

+// PR c++/64701
+// { dg-options "" }
+
+enum { A };
+void
+foo ()
+{
+  int x = ({ do {} while (0); A; });
+}