re PR c++/47207 ([C++0x] ICE: in decl_constant_var_p, at cp/decl2.c:3563 on invalid code)

	PR c++/47207
	* decl2.c (decl_constant_var_p): A constexpr var needs an
	initializer to be constant.
	* semantics.c (cxx_eval_constant_expression): Complain about
	constexpr var used in its own initializer.
	* call.c (set_up_extended_ref_temp): Set
	DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P too.

From-SVN: r170365

1 files changed, 7 insertions, 6 deletions

diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index a4b7dfa..93d44a4 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -3550,20 +3550,21 @@ decl_constant_var_p (tree decl)
   tree type = TREE_TYPE (decl);
   if (TREE_CODE (decl) != VAR_DECL)
     return false;
-  if (DECL_DECLARED_CONSTEXPR_P (decl))
-    ret = true;
-  else if (CP_TYPE_CONST_NON_VOLATILE_P (type)
-	   && INTEGRAL_OR_ENUMERATION_TYPE_P (type))
+  if (DECL_DECLARED_CONSTEXPR_P (decl)
+      || (CP_TYPE_CONST_NON_VOLATILE_P (type)
+	  && INTEGRAL_OR_ENUMERATION_TYPE_P (type)))
     {
       /* We don't know if a template static data member is initialized with
-	 a constant expression until we instantiate its initializer.  */
+	 a constant expression until we instantiate its initializer.  Even
+	 in the case of a constexpr variable, we can't treat it as a
+	 constant until its initializer is complete in case it's used in
+	 its own initializer.  */
       mark_used (decl);
       ret = DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl);
     }
   else
     ret = false;
 
-  gcc_assert (!ret || DECL_INITIAL (decl));
   return ret;
 }