[libc++] Remove _AlgPolicy from std::copy and algorithms using std::copy (#115887)

`std::copy` doesn't use the `_AlgPolicy` for anything other than calling
itself with it, so we can just remove the

[libc++] Remove _AlgPolicy from std::copy and algorithms using std::copy (#115887)

`std::copy` doesn't use the `_AlgPolicy` for anything other than calling
itself with it, so we can just remove the argument. This also removes
the need in a few other algorithms which had an `_AlgPolicy` argument
only to call `copy`.

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[libc++] Granularize <cstddef> includes (#108696)

[libc++] Remove a few unused includes of trivially_copyable.h (#93200)

[libc++][NFC] Simplify copy and move lowering to memmove a bit (#83574)

We've introduced `__constexpr_memmove` a while ago, which simplified the
implementation of the copy and move lowering a bit.

[libc++][NFC] Simplify copy and move lowering to memmove a bit (#83574)

We've introduced `__constexpr_memmove` a while ago, which simplified the
implementation of the copy and move lowering a bit. This allows us to
remove some of the boilerplate.

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[libc++][NFC] Merge is{,_nothrow,_trivially}{,_copy,_move,_default}{_assignable,_constructible} (#85308)

These headers have become very small by using compiler builtins, often
containing only two d

[libc++][NFC] Merge is{,_nothrow,_trivially}{,_copy,_move,_default}{_assignable,_constructible} (#85308)

These headers have become very small by using compiler builtins, often
containing only two declarations. This merges these headers, since
there doesn't seem to be much of a benefit keeping them separate.

Specifically, `is_{,_nothrow,_trivially}{assignable,constructible}` are
kept and the `copy`, `move` and `default` versions of these type traits
are moved in to the respective headers.

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[libc++] Fix missing and incorrect push/pop macros (#79204)

We recently noticed that the unwrap_iter.h file was pushing macros, but
it was pushing them again instead of popping them at the end of t

[libc++] Fix missing and incorrect push/pop macros (#79204)

We recently noticed that the unwrap_iter.h file was pushing macros, but
it was pushing them again instead of popping them at the end of the
file. This led to libc++ basically swallowing any custom definition of
these macros in user code:

#define min HELLO
#include <algorithm>
// min is not HELLO anymore, it's not defined

While investigating this issue, I noticed that our push/pop pragmas were
actually entirely wrong too. Indeed, instead of pushing macros like
`move`, we'd push `move(int, int)` in the pragma, which is not a valid
macro name. As a result, we would not actually push macros like `move`
-- instead we'd simply undefine them. This led to the following code not
working:

#define move HELLO
#include <algorithm>
// move is not HELLO anymore

Fixing the pragma push/pop incantations led to a cascade of issues
because we use identifiers like `move` in a large number of places, and
all of these headers would now need to do the push/pop dance.

This patch fixes all these issues. First, it adds a check that we don't
swallow important names like min, max, move or refresh as explained
above. This is done by augmenting the existing
system_reserved_names.gen.py test to also check that the macros are what
we expect after including each header.

Second, it fixes the push/pop pragmas to work properly and adds missing
pragmas to all the files I could detect a failure in via the newly added
test.

rdar://121365472

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[libc++] Format the code base (#74334)

This patch runs clang-format on all of libcxx/include and libcxx/src, in
accordance with the RFC discussed at [1]. Follow-up patches will format
the benchmar

[libc++] Format the code base (#74334)

This patch runs clang-format on all of libcxx/include and libcxx/src, in
accordance with the RFC discussed at [1]. Follow-up patches will format
the benchmarks, the test suite and remaining parts of the code. I'm
splitting this one into its own patch so the diff is a bit easier to
review.

This patch was generated with:

find libcxx/include libcxx/src -type f \
| grep -v 'module.modulemap.in' \
| grep -v 'CMakeLists.txt' \
| grep -v 'README.txt' \
| grep -v 'libcxx.imp' \
| grep -v '__config_site.in' \
| xargs clang-format -i

A Git merge driver is available in libcxx/utils/clang-format-merge-driver.sh
to help resolve merge and rebase issues across these formatting changes.

[1]: https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all

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[libc++] Fix std::copy and std::move for ranges with potentially overlapping tail padding

This fixes thr bug reported in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108846.

Reviewed By: ldionne, #

[libc++] Fix std::copy and std::move for ranges with potentially overlapping tail padding

This fixes thr bug reported in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108846.

Reviewed By: ldionne, #libc

Spies: mstorsjo, libcxx-commits

Differential Revision: https://reviews.llvm.org/D151953

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Reapply "[libc++][ranges]Refactor `copy{,_backward}` and `move{,_backward}`"

This reverts commit a6e1080b87db8fbe0e1afadd96af5a3c0bd5e279.

Fix the conditions when the `memmove` optimization can be

Reapply "[libc++][ranges]Refactor `copy{,_backward}` and `move{,_backward}`"

This reverts commit a6e1080b87db8fbe0e1afadd96af5a3c0bd5e279.

Fix the conditions when the `memmove` optimization can be applied and refactor them out into a reusable type trait, fix and significantly expand the tests.

Differential Revision: https://reviews.llvm.org/D139235

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[libc++][ranges]Refactor `copy{,_backward}` and `move{,_backward}`

Instead of using `reverse_iterator`, share the optimization between the 4 algorithms. The key observation here that `memmove` appli

[libc++][ranges]Refactor `copy{,_backward}` and `move{,_backward}`

Instead of using `reverse_iterator`, share the optimization between the 4 algorithms. The key observation here that `memmove` applies to both `copy` and `move` identically, and to their `_backward` versions very similarly. All algorithms now follow the same pattern along the lines of:
```
if constexpr (can_memmove<InIter, OutIter>) {
memmove(first, last, out);
} else {
naive_implementation(first, last, out);
}
```
A follow-up will delete `unconstrained_reverse_iterator`.

This patch removes duplication and divergence between `std::copy`, `std::move` and `std::move_backward`. It also improves testing:
- the test for whether the optimization is used only applied to `std::copy` and, more importantly, was essentially a no-op because it would still pass if the optimization was not used;
- there were no tests to make sure the optimization is not used when the effect would be visible.

Differential Revision: https://reviews.llvm.org/D130695

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