[libcxx-commits] [PATCH] D128146: [libc++] Use uninitialized algorithms for vector

[Evgeny Eltsin via Phabricator via libcxx-commits]

eaeltsin added a comment.

Here is a sample that was compiling Ok before the change and is now broken: https://godbolt.org/z/djPG94f69

  #include <vector>
  
  template <typename B>
  struct REAL_TYPEDEF {
    typedef B base_type;
    B v;
    REAL_TYPEDEF() : v(0){}
    explicit REAL_TYPEDEF(B v) : v(v){}
  
    inline bool operator==(const REAL_TYPEDEF<B>& rhs) const {
      return v == rhs.v;
    }
  };
  
  template <typename T>
  inline bool operator!=(const T& lhs, const T& rhs) {
    return !(lhs == rhs);
  }
  
  namespace zim {
  
  typedef int offset_type;
  
  #define TYPEDEF(NAME, TYPE)                              \
    struct NAME : public REAL_TYPEDEF<TYPE> {              \
      explicit NAME(TYPE v = 0) : REAL_TYPEDEF<TYPE>(v){}  \
    };                                                     \
    static_assert(sizeof(NAME) == sizeof(TYPE), "");
  
  TYPEDEF(offset_t, offset_type)
  
  int foo(int n) {
    std::vector<offset_t> b;
  
    b.reserve(n);
  
    return b.size();
  }
  
  };  // namespace zim

New output:

  In file included from <source>:1:
  In file included from /opt/compiler-explorer/clang-trunk-20220802/bin/../include/c++/v1/vector:296:
  In file included from /opt/compiler-explorer/clang-trunk-20220802/bin/../include/c++/v1/__split_buffer:24:
  In file included from /opt/compiler-explorer/clang-trunk-20220802/bin/../include/c++/v1/memory:858:
  In file included from /opt/compiler-explorer/clang-trunk-20220802/bin/../include/c++/v1/__memory/ranges_uninitialized_algorithms.h:22:
  /opt/compiler-explorer/clang-trunk-20220802/bin/../include/c++/v1/__memory/uninitialized_algorithms.h:628:21: error: use of overloaded operator '!=' is ambiguous (with operand types 'std::reverse_iterator<zim::offset_t *>' and 'std::reverse_iterator<zim::offset_t *>')
      while (__first1 != __last1) {
             ~~~~~~~~ ^  ~~~~~~~
  /opt/compiler-explorer/clang-trunk-20220802/bin/../include/c++/v1/vector:914:27: note: in instantiation of function template specialization 'std::__uninitialized_allocator_move_if_noexcept<std::allocator<zim::offset_t>, std::reverse_iterator<zim::offset_t *>, std::reverse_iterator<zim::offset_t *>, zim::offset_t, void>' requested here
      __v.__begin_   = std::__uninitialized_allocator_move_if_noexcept(
                            ^
  /opt/compiler-explorer/clang-trunk-20220802/bin/../include/c++/v1/vector:1501:9: note: in instantiation of member function 'std::vector<zim::offset_t>::__swap_out_circular_buffer' requested here
          __swap_out_circular_buffer(__v);
          ^
  <source>:35:5: note: in instantiation of member function 'std::vector<zim::offset_t>::reserve' requested here
    b.reserve(n);
      ^
  /opt/compiler-explorer/clang-trunk-20220802/bin/../include/c++/v1/__iterator/reverse_iterator.h:233:1: note: candidate function [with _Iter1 = zim::offset_t *, _Iter2 = zim::offset_t *]
  operator!=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
  ^
  <source>:16:13: note: candidate function [with T = std::reverse_iterator<zim::offset_t *>]
  inline bool operator!=(const T& lhs, const T& rhs) {
              ^
  1 error generated.


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  https://reviews.llvm.org/D128146/new/

https://reviews.llvm.org/D128146