re PR c++/50012 (C++ front end misses -Wsign-compare warnings when extraneous parentheses are present)

gcc/:
	PR c++/50012
	* tree.h (TYPE_QUALS): Add cast to int.
	(TYPE_QUALS_NO_ADDR_SPACE): Likewise.
gcc/cp:
	PR c++/50012
	* typeck.c (enum_cast_to_int): New static function.
	(cp_build_binary_op): When handling warn_sign_compare, don't test
	for TREE_NO_WARNING.  Do call enum_cast_to_int.
	* call.c (avoid_sign_compare_warnings): Remove static function.
	(build_new_op_1): Don't call avoid_sign_compare_warnings.
gcc/testsuite/:
	PR c++/50012
	* g++.dg/warn/Wsign-compare-4.C: New.

From-SVN: r183178