From: Matthias Maier <tamiko@43-1.org>
Date: Sat, 23 May 2020 04:54:30 +0000 (-0500)
Subject: CMake: remove obsolete compiler bug tests
X-Git-Tag: v9.3.0-rc1~1579^2~2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2199dfde67fc8fbc08875788464e7a0bc1f4e6c0;p=dealii.git

CMake: remove obsolete compiler bug tests

The bugs

  DEAL_II_TEMPL_SPEC_FRIEND_BUG
  DEAL_II_CONST_MEMBER_DEDUCTION_BUG
  DEAL_II_BIND_NO_CONST_OP_PARENTHESES

do not trigger for any compiler we currently use (including gcc-4.9 up
to gcc-10, clang-4 up to clang-10 and corresponding apple clang, MSVC
2017 and 2019, icc 19*)

The bug

  DEAL_II_MEMBER_ARRAY_SPECIALIZATION_BUG

triggers only on MSVC 2017 and 2019 but the preprocessor macro is not
used in the library any more
---

diff --git a/cmake/checks/check_03_compiler_bugs.cmake b/cmake/checks/check_03_compiler_bugs.cmake
index f5b5ae7b53..5eb17500e8 100644
--- a/cmake/checks/check_03_compiler_bugs.cmake
+++ b/cmake/checks/check_03_compiler_bugs.cmake
@@ -19,139 +19,6 @@
 #                                                                      #
 ########################################################################
 
-#
-# In some cases, we would like to name partial specializations
-# as friends. However, the standard forbids us to do so. But
-# then, we can declare the general template as a friend, and
-# at least gcc extends the friendship to all specializations
-# of the templates, which is not what the standard says.
-#
-# With other compilers, most notably cxx, this does not work.
-# In this case, we can make individual specializations friends,
-# which in turn gcc rejects. So check, whether this is possible.
-#
-# The respective clause in the standard is 14.5.3.1, which gives
-# this example:
-#   template<class T> class task {
-#     friend class task<int>;
-#   };
-#
-# - Wolfgang Bangerth, Matthias Maier, rewritten 2012
-#
-CHECK_CXX_COMPILER_BUG(
-  "
-  template <int N, typename T> class X;
-  template <typename T>        class X<1,T>;
-
-  template <typename P> class Y {
-      static int i;
-      template <int N, typename T> friend class X;
-      friend class X<1,P>;
-  };
-
-  template <typename T> class X<1,T> {
-      int f () { return Y<T>::i; };     // access private field
-  };
-  int main() { return 0; }
-  "
-  DEAL_II_TEMPL_SPEC_FRIEND_BUG)
-
-
-#
-# This is a variant of the previous test. Some icc 11.0
-# builds (sub-releases) on Windows apparently don't allow
-# the declaration of an explicit specialization of member
-# arrays of templates:
-#
-# template <int dim>
-# struct X
-# {
-#    static const int N = 2*dim;
-#    static const int x[N];
-# };
-# template <> const int X<2>::x[N];
-#
-# That version of icc requests that there be an initialization,
-# i.e. it thinks that this is the *definition*, not merely a
-# *declaration* of an explicit specialization. This is wrong,
-# however.
-#
-# - Wolfgang Bangerth, Matthias Maier, rewritten 2012
-#
-CHECK_CXX_COMPILER_BUG(
-  "
-  template <int dim>
-  struct X
-  {
-    static const int N = 2*dim;
-    static const int x[N];
-  };
-  template <> const int X<2>::x[N];
-  int main() { return 0; }
-  "
-  DEAL_II_MEMBER_ARRAY_SPECIALIZATION_BUG
-  )
-
-
-#
-# Some older versions of gcc deduce pointers to const functions in
-# template contexts to pointer-to-function of const objects.
-# This is not correct
-#
-# Check for this misfeature.
-#
-# - Wolfgang Bangerth, Matthias Maier, rewritten 2012
-#
-CHECK_CXX_COMPILER_BUG(
-  "
-  template <typename T> struct identity { typedef T type; };
-  template <typename C> void new_thread (void (C::*fun_ptr)(),
-                typename identity<C>::type &c) {}
-  template <typename C> void new_thread (void (C::*fun_ptr)() const,
-                const typename identity<C>::type &c) {}
-  struct X { void f() const{} };
-
-  int main()
-  {
-    X x;
-    new_thread (&X::f, x);
-  }
-  "
-  DEAL_II_CONST_MEMBER_DEDUCTION_BUG
-  )
-
-
-
-#
-# Microsoft Visual C++ has a bug where the resulting object
-# from calling std::bind does not have a const operator(),
-# so we cannot pass such objects as const references as we
-# usually do with input arguments of other functions.
-#
-# - Wolfgang Bangerth, 2014
-#
-ADD_FLAGS(CMAKE_REQUIRED_FLAGS "${DEAL_II_CXX_FLAGS}")
-CHECK_CXX_COMPILER_BUG(
-  "
-  #include <functional>
-
-  void f(int, int) {}
-
-  template <typename F>
-  void g(const F &func)
-  {
-    func(1);
-  }
-
-  int main ()
-  {
-    g (std::bind(&f, std::placeholders::_1, 1));
-  }
-  "
-  DEAL_II_BIND_NO_CONST_OP_PARENTHESES
-  )
-RESET_CMAKE_REQUIRED()
-
 
 #
 # In intel (at least 13.1 and 14), vectorization causes