On 14/08/18 09:59 -0400, Marek Polacek wrote:
On Tue, Aug 14, 2018 at 02:55:17PM +0100, Jonathan Wakely wrote:* include/std/chrono (__check_overflow): Simplify definition. (_Checked_integral_constant): Remove.Tested x86_64-linux, committed to trunk.commit c0dec9d05de4695136694f78f2f76e3c9f15b3f1 Author: Jonathan Wakely <jwak...@redhat.com> Date: Tue Aug 14 14:33:38 2018 +0100 Simplify overflow checks in duration literals * include/std/chrono (__check_overflow): Simplify definition. (_Checked_integral_constant): Remove. diff --git a/libstdc++-v3/include/std/chrono b/libstdc++-v3/include/std/chrono index da03fdccce4..871c896144a 100644 --- a/libstdc++-v3/include/std/chrono +++ b/libstdc++-v3/include/std/chrono @@ -900,24 +900,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wliteral-suffix" - template<typename _Rep, unsigned long long _Val> - struct _Checked_integral_constant - : integral_constant<_Rep, static_cast<_Rep>(_Val)> - { - static_assert(_Checked_integral_constant::value >= 0 - && _Checked_integral_constant::value == _Val, - "literal value cannot be represented by duration type"); - }; - template<typename _Dur, char... _Digits> constexpr _Dur __check_overflow() { using _Val = __parse_int::_Parse_int<_Digits...>; - using _Rep = typename _Dur::rep; - // TODO: should be simply integral_constant<_Rep, _Val::value> - // but GCC doesn't reject narrowing conversions to _Rep.Note that I fixed 57891 yesterday. Or is this either 65043 or 78244?
Yes, thanks for that! That was what made me revisit the TODO. But using integral_constant there doesn't produce the required error, because it's in a system header. The standard requires it to be ill-formed, so I can't rely on the narrowing diagnostic :-( But I realised it could be simplified anyway (and that could have been done years ago, without waiting for the fixes to narrowing in template arguments).
