commit e71736621b375d376091a50d17c0cbfb789e2536
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Jun 9 13:59:04 2011 -0400

    	* semantics.c (maybe_constant_value): Handle overflowed input.

diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index bf6486b..481318e 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -6902,7 +6902,8 @@ non_const_var_error (tree r)
       else if (CP_TYPE_VOLATILE_P (type))
 	inform (DECL_SOURCE_LOCATION (r),
 		"%q#D is volatile", r);
-      else if (!DECL_INITIAL (r))
+      else if (!DECL_INITIAL (r)
+	       || !TREE_CONSTANT (DECL_INITIAL (r)))
 	inform (DECL_SOURCE_LOCATION (r),
 		"%qD was not initialized with a constant "
 		"expression", r);
@@ -7337,7 +7338,14 @@ maybe_constant_value (tree t)
       || type_unknown_p (t)
       || !potential_constant_expression (t)
       || value_dependent_expression_p (t))
-    return t;
+    {
+      if (TREE_OVERFLOW_P (t))
+	{
+	  t = build_nop (TREE_TYPE (t), t);
+	  TREE_CONSTANT (t) = false;
+	}
+      return t;
+    }
 
   r = cxx_eval_outermost_constant_expr (t, true);
 #ifdef ENABLE_CHECKING
diff --git a/libstdc++-v3/testsuite/20_util/ratio/cons/cons_overflow_neg.cc b/libstdc++-v3/testsuite/20_util/ratio/cons/cons_overflow_neg.cc
index 83f5ce1..8aa72f2 100644
--- a/libstdc++-v3/testsuite/20_util/ratio/cons/cons_overflow_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/ratio/cons/cons_overflow_neg.cc
@@ -51,4 +51,5 @@ test04()
 // { dg-error "required from here" "" { target *-*-* } 46 }
 // { dg-error "denominator cannot be zero" "" { target *-*-* } 268 }
 // { dg-error "out of range" "" { target *-*-* } 269 }
-// { dg-error "overflow in constant expression" "" { target *-*-* } 109 }
+// { dg-error "overflow in constant expression" "" { target *-*-* } 61 }
+// { dg-prune-output "not a member" }