mbox series

[v6,0/6] c++, libstdc++: get std::is_object to dispatch to new built-in traits

Message ID 20230612224109.20749-1-kmatsui@cs.washington.edu
Headers
Series c++, libstdc++: get std::is_object to dispatch to new built-in traits |

Message

Ken Matsui June 12, 2023, 10:39 p.m. UTC 
  Hi,

This patch series gets std::is_object to dispatch to built-in traits and
implements the following built-in traits, on which std::object depends.

	* __is_reference
	* __is_function
	* __is_void

std::is_object was depending on them with disjunction and negation.

__not_<__or_<is_function<_Tp>, is_reference<_Tp>, is_void<_Tp>>>::type

Therefore, this patch uses them directly instead of implementing an additional
built-in trait __is_object, which makes the compiler slightly bigger and
slower.

__bool_constant<!(__is_function(_Tp) || __is_reference(_Tp) || __is_void(_Tp))>

This would instantiate only __bool_constant<true> and __bool_constant<false>,
which can be mostly shared. That is, the purpose of built-in traits is
considered as achieved.

Changes in v6

	* Removed the built-in-like type trait for is_object.

Ken Matsui (6):
  c++: implement __is_reference built-in trait
  libstdc++: use new built-in trait __is_reference for std::is_reference
  c++: implement __is_function built-in trait
  libstdc++: use new built-in trait __is_function for std::is_function
  c++, libstdc++: implement __is_void built-in trait
  libstdc++: make std::is_object dispatch to new built-in traits

 gcc/cp/constraint.cc                          |  9 +++
 gcc/cp/cp-trait.def                           |  3 +
 gcc/cp/semantics.cc                           | 12 ++++
 gcc/testsuite/g++.dg/ext/has-builtin-1.C      |  9 +++
 gcc/testsuite/g++.dg/ext/is_function.C        | 58 +++++++++++++++++++
 gcc/testsuite/g++.dg/ext/is_reference.C       | 34 +++++++++++
 gcc/testsuite/g++.dg/ext/is_void.C            | 35 +++++++++++
 gcc/testsuite/g++.dg/tm/pr46567.C             |  6 +-
 libstdc++-v3/include/bits/cpp_type_traits.h   | 15 -----
 libstdc++-v3/include/debug/helper_functions.h |  5 +-
 libstdc++-v3/include/std/type_traits          | 52 +++++++++++++++++
 11 files changed, 217 insertions(+), 21 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/ext/is_function.C
 create mode 100644 gcc/testsuite/g++.dg/ext/is_reference.C
 create mode 100644 gcc/testsuite/g++.dg/ext/is_void.C