Upstream-Status: Inappropriate [Backport]
From a5e7415bfbe41941768106dc5819bf3fff1b8435 Mon Sep 17 00:00:00 2001
From: jason <jason@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri, 8 Apr 2011 15:01:50 +0000
Subject: [PATCH 086/200] 	PR c++/48450
 	* c-family/c-common.c (c_common_truthvalue_conversion): Don't ignore
 	conversion from C++0x scoped enum.
 	* cp/cvt.c (ocp_convert): Handle converting scoped enum to bool.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-4_6-branch@172191 138bc75d-0d04-0410-961f-82ee72b054a4

index c0c01b2..0be3996 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -3938,16 +3938,25 @@ c_common_truthvalue_conversion (location_t location, tree expr)
 	}
 
     CASE_CONVERT:
-      /* Don't cancel the effect of a CONVERT_EXPR from a REFERENCE_TYPE,
-	 since that affects how `default_conversion' will behave.  */
-      if (TREE_CODE (TREE_TYPE (expr)) == REFERENCE_TYPE
-	  || TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == REFERENCE_TYPE)
-	break;
-      /* If this is widening the argument, we can ignore it.  */
-      if (TYPE_PRECISION (TREE_TYPE (expr))
-	  >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (expr, 0))))
-	return c_common_truthvalue_conversion (location,
-					       TREE_OPERAND (expr, 0));
+      {
+	tree totype = TREE_TYPE (expr);
+	tree fromtype = TREE_TYPE (TREE_OPERAND (expr, 0));
+
+	/* Don't cancel the effect of a CONVERT_EXPR from a REFERENCE_TYPE,
+	   since that affects how `default_conversion' will behave.  */
+	if (TREE_CODE (totype) == REFERENCE_TYPE
+	    || TREE_CODE (fromtype) == REFERENCE_TYPE)
+	  break;
+	/* Don't strip a conversion from C++0x scoped enum, since they
+	   don't implicitly convert to other types.  */
+	if (TREE_CODE (fromtype) == ENUMERAL_TYPE
+	    && ENUM_IS_SCOPED (fromtype))
+	  break;
+	/* If this isn't narrowing the argument, we can ignore it.  */
+	if (TYPE_PRECISION (totype) >= TYPE_PRECISION (fromtype))
+	  return c_common_truthvalue_conversion (location,
+						 TREE_OPERAND (expr, 0));
+      }
       break;
 
     case MODIFY_EXPR:
index 8ab0001..290b926 100644
--- a/gcc/cp/cvt.c
+++ b/gcc/cp/cvt.c
@@ -727,7 +727,13 @@ ocp_convert (tree type, tree expr, int convtype, int flags)
 	  return error_mark_node;
 	}
       if (code == BOOLEAN_TYPE)
-	return cp_truthvalue_conversion (e);
+	{
+	  /* We can't implicitly convert a scoped enum to bool, so convert
+	     to the underlying type first.  */
+	  if (SCOPED_ENUM_P (intype) && (convtype & CONV_STATIC))
+	    e = convert (ENUM_UNDERLYING_TYPE (intype), e);
+	  return cp_truthvalue_conversion (e);
+	}
 
       converted = fold_if_not_in_template (convert_to_integer (type, e));
 
new file mode 100644
index 0000000..10e510b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/enum9.C
@@ -0,0 +1,5 @@
+// { dg-options -std=c++0x }
+
+enum class E { };
+E f();
+bool b2 = static_cast<bool>(f());
-- 
1.7.0.4