re PR c++/11667 (wider-than-int enums never compare equal to 0)

	PR c++/11667
	* c-common.c (shorten_compare): Take into account differences
	between C and C++ representation for enumeration types.
	* tree.h (set_min_and_max_values_for_integral_type): Declare.
	* stor-layout.c (set_min_and_max_values_for_integral_type): New
	function, broken out from ...
	(fixup_signed_type): ... here and ...
	(fixup_unsigned_type): ... here.

	PR c++/11667
	* call.c (standard_conversion): Allow all integral->enumeral
	conversions, after marking them as bad.
	* decl.c (finish_enum): Make sure that all enumerators are
	properly converted to the underlying type.
	(build_enumerator): Set DECL_CONTEXT for namespace-scope
	enumeration types.
	* pt.c (tsubst_copy): Adjust handling of CONST_DECLs accordingly.
	(tsubst_enum): Tidy.

	* Make-lang.in (typeck.o): Depend on convert.h.
	(class.o): Likewise.
	(rtti.o): Likewise.
	* call.c: Include convert.h.
	(convert_arg_to_ellipsis): Use convert_to_real.
	* class.c: Include convert.h.
	(build_base_path): Use convert_to_integer.
	* rtti.c: Include convert.h.
	(build_headof): Use convert_to_integer.
	* typeck.c: Include convert.h.
	(decay_conversion): Use convert_to_integer.
	(build_unary_op): Use build_nop.
	(get_delta_difference): Use convert_to_integer.
	(build_ptrmemfunc): Avoid unncessary conversions.

From-SVN: r69909

1 files changed, 6 insertions, 4 deletions

diff --git a/gcc/c-common.c b/gcc/c-common.c
index c579b16..8dea43b 100644
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -2214,10 +2214,12 @@ shorten_compare (tree *op0_ptr, tree *op1_ptr, tree *restype_ptr,
       type = c_common_signed_or_unsigned_type (unsignedp0,
 					       TREE_TYPE (primop0));
 
-      /* If TYPE is an enumeration, then we need to get its min/max
-	 values from it's underlying integral type, not the enumerated
-	 type itself.  */
-      if (TREE_CODE (type) == ENUMERAL_TYPE)
+      /* In C, if TYPE is an enumeration, then we need to get its
+	 min/max values from it's underlying integral type, not the
+	 enumerated type itself.  In C++, TYPE_MAX_VALUE and
+	 TYPE_MIN_VALUE have already been set correctly on the
+	 enumeration type.  */
+      if (!c_dialect_cxx() && TREE_CODE (type) == ENUMERAL_TYPE)
 	type = c_common_type_for_size (TYPE_PRECISION (type), unsignedp0);
 
       maxval = TYPE_MAX_VALUE (type);