[libcxx-commits] [PATCH] D126616: [libc++] Implement ranges::move{, _backward}

Nikolas Klauser via Phabricator via libcxx-commits libcxx-commits at lists.llvm.org
Sat Jun 11 13:28:04 PDT 2022

philnik added inline comments.

Comment at: libcxx/include/__algorithm/move.h:49
+   && !is_trivially_copyable<_InValueT>::value
var-const wrote:
> philnik wrote:
> > var-const wrote:
> > > Can you provide a bit more context about this workaround?
> > What are you asking about exactly? Why I have to check for `is_trivially_copyable`? That's because `__builtin_memmove` requires the type to be trivially_copable. Or do you mean something else?
> I'm asking about the preprocessor guard, why the check is only done if the compiler is not GCC.
GCC currently doesn't support `__builtin_memmove` during constant evaluation, so we have to fall back to the naive implementation.

Comment at: libcxx/test/std/algorithms/alg.modifying.operations/alg.move/ranges.move.pass.cpp:113
+  test_in_iterators<cpp20_output_iterator<int*>>();
+  test_in_iterators<cpp20_input_iterator<int*>>();
+  test_in_iterators<forward_iterator<int*>>();
var-const wrote:
> Can you please add a brief comment explaining why `cpp17_input_iterator` doesn't work?
Because I forgot to add it :P

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