Fix PR c/40033 (ICE-on-invalid)

Fix PR c/40033 (ICE-on-invalid)

[Joseph S. Myers]

This patch fixes PR 40033, an ICE-on-invalid regression where
error_mark_node wrongly got wrapped in a C_MAYBE_CONST_EXPR.

Bootstrapped with no regressions on x86_64-unknown-linux-gnu.  Applied
to mainline.

2009-10-23  Joseph Myers  <joseph@codesourcery.com>

	PR c/40033
	* c-typeck.c (c_finish_stmt_expr): Do not wrap error_mark_node in
	a C_MAYBE_CONST_EXPR.

testsuite:
2009-10-23  Joseph Myers  <joseph@codesourcery.com>

	PR c/40033
	* gcc.dg/noncompile/pr40033-1.c: New test.

Index: testsuite/gcc.dg/noncompile/pr40033-1.c
===================================================================
--- testsuite/gcc.dg/noncompile/pr40033-1.c	(revision 0)
+++ testsuite/gcc.dg/noncompile/pr40033-1.c	(revision 0)
@@ -0,0 +1,7 @@
+/* ICE from error_mark_node being wrapped in a C_MAYBE_CONST_EXPR.  PR
+   40033.  */
+
+void foo()
+{
+  ({ 0,; }); /* { dg-error "expected" } */
+}
Index: c-typeck.c
===================================================================
--- c-typeck.c	(revision 153496)
+++ c-typeck.c	(working copy)
@@ -8653,11 +8653,13 @@ c_finish_stmt_expr (location_t loc, tree
       goto continue_searching;
     }
 
+  if (last == error_mark_node)
+    return last;
+
   /* In the case that the BIND_EXPR is not necessary, return the
      expression out from inside it.  */
-  if (last == error_mark_node
-      || (last == BIND_EXPR_BODY (body)
-	  && BIND_EXPR_VARS (body) == NULL))
+  if (last == BIND_EXPR_BODY (body)
+      && BIND_EXPR_VARS (body) == NULL)
     {
       /* Even if this looks constant, do not allow it in a constant
 	 expression.  */

-- 
Joseph S. Myers
joseph@codesourcery.com