[libcxx-commits] [PATCH] D127159: [libc++] Simplify the char_traits specializations

[Louis Dionne via Phabricator via libcxx-commits]

ldionne requested changes to this revision.
ldionne added inline comments.
This revision now requires changes to proceed.


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Comment at: libcxx/include/__string/char_traits.h:207
+    char_type* move(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT {
+        std::copy_n(__s2, __n, __s1);
+        return __s1;
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philnik wrote:
> mclow.lists wrote:
> > Does this handle overlapping ranges? The old code does.
> > 
> > https://eel.is/c++draft/char.traits.require says it has to handle overlapping ranges.
> While `std::copy_n` doesn't officially support overlapping ranges our implementation forwards trivial types to `__builtin_memmove`, which does handle them properly.
Can you please add tests to cover that (or ensure we already do)?

Also, if we keep this, let's add a comment like `// our implementation of std::copy_n handles overlapping ranges`.


Repository:
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  https://reviews.llvm.org/D127159/new/

https://reviews.llvm.org/D127159