Use the unoptimized routines for volatile source types

[hiraditya]

Summary

As reported in: D147741

[philnik]

Please add the regression test from @hans to make sure we don't reintroduce the bug.

[hiraditya]

Added testcase provided by @hans

[philnik]

LGTM with comment addressed and green CI.

libcxx/test/std/containers/sequences/vector/vector.cons/copy.pass.cpp

103–114

This should also work.

[hiraditya]

Updated test.

[hans]

Thanks!

libcxx/include/__memory/uninitialized_algorithms.h

 
 template <class _Alloc,
           class _In,
           class _RawTypeIn = __remove_const_t<_In>,
           class _Out,
           __enable_if_t<
               // using _RawTypeIn because of the allocator<T const> extension
               is_trivially_copy_constructible<_RawTypeIn>::value && is_trivially_copy_assignable<_RawTypeIn>::value &&
-              is_same<__remove_cv_t<_In>, __remove_cv_t<_Out> >::value &&
+              is_same<__remove_const_t<_In>, __remove_const_t<_Out> >::value &&
               __allocator_has_trivial_copy_construct<_Alloc, _RawTypeIn>::value>* = nullptr>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Out*
 __uninitialized_allocator_copy_impl(_Alloc&, _In* __first1, _In* __last1, _Out* __first2) {
   // TODO: Remove the const_cast once we drop support for std::allocator<T const>
   if (__libcpp_is_constant_evaluated()) {
     while (__first1 != __last1) {
       std::__construct_at(std::__to_address(__first2), *__first1);
       ++__first1;

libcxx/test/std/containers/sequences/vector/vector.cons/copy.pass.cpp

#if TEST_STD_VER >= 11
       assert(is_contiguous_container_asan_correct(v));
       assert(is_contiguous_container_asan_correct(v2));
     }
 #endif
 
     return true;
 }
 
+void test_copy_from_volatile_src() {
+    volatile int src[] = {1, 2, 3};
+    std::vector<int> v(src, src + 3);
+    assert(v[0] == 1);
+    assert(v[1] == 2);
+    assert(v[2] == 3);
+}
+
 int main(int, char**)
 {
     tests();
 #if TEST_STD_VER > 17
     static_assert(tests());
 #endif
+    test_copy_from_volatile_src();
     return 0;
 }