[docs] Add PowerPC release notes for LLVM 14

[lei]

remove unintented change

[jsji]

LGTM.

[ldionne]

LGTM for libc++. I assume this is targeting release/14.x only.

[lei]

In D120907#3357433, @ldionne wrote:

LGTM for libc++. I assume this is targeting release/14.x only.

yes

[lei]

Commited to release/14.x via ce1e90fc8dbacdaff0310e50090ec3cfdfce4def

clang/docs/ReleaseNotes.rst

 
 Major New Features
 ------------------
 
 - Added SPIR-V triple and binary generation using external ``llvm-spirv`` tool.
   For more details refer to :ref:`the SPIR-V support section <spir-v>`.
 - Completed support of OpenCL C 3.0 and C++ for OpenCL 2021 at experimental
   state.
--  ...
+
+- Prebuilt AIX7.2 TL5 SP3+ binary available with following notes and
+  limitations:
+  - C++ driver modes use the system libc++ headers. These headers are included
+    in the optional ``libc++.adt.include`` fileset on AIX.
+  - LTO, although not disabled, is not recommended.
+  - Shared libraries builds (``-shared``) must use explicit symbol export
+    options and/or export lists (e.g., with ``-bE:``) on the link step. Clang
+    currently will not automatically generate symbol export lists as implicit
+    linker inputs.
+
+- ``float.h`` now exposes (in hosted mode) extensions made available from the
+  AIX system header.
 
 Improvements to Clang's diagnostics
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 - -Wbitwise-instead-of-logical (part of -Wbool-operation) warns about use of bitwise operators with boolean operands which have side effects.
 
 - Added diagnostic groups to control diagnostics for attribute extensions by
   adding groups ``-Wc++N-attribute-extensions`` (where ``N`` is the standard

 - Maximum _ExtInt size was decreased from 16,777,215 bits to 8,388,608 bits.
   Motivation for this was discussed in PR51829.
 - Configuration file syntax extended with ``<CFGDIR>`` token. This expands to
   the base path of the current config file. See :ref:`configuration-files` for
   details.
 - The ``-E -P`` preprocessor output now always omits blank lines, matching
   gcc behaviour. Previously, up to 8 consecutive blank lines could appear
   in the output.
+- AIX platform-related predefined macros added:
+  ``_ARCH_PPC64``, ``__HOS_AIX__``, ``__PPC``, ``__THW_BIG_ENDIAN__``,
+  ``__THW_PPC__``, and ``__powerpc``
 
 New Compiler Flags
 ------------------
 
 - Clang plugin arguments can now be passed through the compiler driver via
   ``-fplugin-arg-pluginname-arg``, similar to GCC's ``-fplugin-arg``.
 - The ``-mno-bti-at-return-twice`` flag will make sure a BTI instruction won't
   be added after a setjmp or possible other return-twice construct (ARM backend
   only).
 - The ``--start-no-unused-arguments`` and ``--end-no-unused-arguments`` flags
   allow silencing warnings about unused arguments for only a subset of
   the command line arguments, keeping potential warnings for other arguments
   outside of such a region.
 - ``-falign-loops=N`` (N is a power of 2) is now supported for non-LTO cases.
   (`D106701 <https://reviews.llvm.org/D106701>`_)
 - The ``-fminimize-whitespace`` flag allows removing redundant whitespace
   from preprocessor output (``-E`` flag). When combined with ``-P``, this
   includes newlines. Otherwise, only indention is removed (other horizontal
   whitespace is always collapsed).
   The motivation is to improve compiler cache hit rate by becoming invariant
   to whitespace changes, such as reformatting using clang-format. Patches
   for `ccache <https://github.com/ccache/ccache/pull/815>`_ and
   `sccache <https://github.com/mozilla/sccache/pull/1055>`_ are under review.
 
+- Clang now accepts "allowlist" spelling for ``-objcmt-allowlist-dir-path``.
+
 Deprecated Compiler Flags
 -------------------------
 
 - -Wweak-template-vtables has been deprecated and no longer has any effect. The
   flag will be removed in the next release.
 
 Modified Compiler Flags
 -----------------------

 
 - __has_cpp_attribute, __has_c_attribute, __has_attribute, and __has_declspec
   will now macro expand their argument. This causes a change in behavior for
   code using ``__has_cpp_attribute(__clang__::attr)`` (and same for
   ``__has_c_attribute``) where it would previously expand to ``0`` for all
   attributes, but will now issue an error due to the expansion of the
   predefined ``__clang__`` macro.
 
+- Improved handling of ``__attribute__((__aligned__))`` on AIX to match GCC.
+
 Windows Support
 ---------------
 
 - An MSVC compatibility workaround for C++ operator names was removed. As a
   result, the ``<query.h>`` Windows SDK header may not compile out of the box.
   Users should use a recent SDK and pass ``-DQUERY_H_RESTRICTION_PERMISSIVE``
   or pass ``/permissive`` to disable C++ operator names altogether. See
   `PR42427 <https://llvm.org/pr42427>` for more info.

libcxx/docs/ReleaseNotes.rst

 - The C++20 ``<coroutine>`` implementation has been completed.
 
 - More C++20 features have been implemented. :doc:`Status/Cxx20` has the full
   overview of libc++'s C++20 implementation status.
 
 - More C++2b features have been implemented. :doc:`Status/Cxx2b` has the full
   overview of libc++'s C++2b implementation status.
 
+- 16-bit ``wchar_t`` handling added for ``codecvt_utf8``, ``codecvt_utf16`` and
+  ``codecvt_utf8_utf16``.
+
 API Changes
 -----------
 
 - The functions ``std::atomic<T*>::fetch_(add|sub)`` and
   ``std::atomic_fetch_(add|sub)`` no longer accept a function pointer. While
   this is technically an API break, the invalid syntax isn't supported by
   libstdc++ and MSVC STL.  See https://godbolt.org/z/49fvzz98d.
 

llvm/docs/ReleaseNotes.rst

 Changes to the Hexagon Target
 -----------------------------
 
 * ...
 
 Changes to the PowerPC Target
 -----------------------------
 
-During this release ...
+Linux improvements:
+* Provided a number of builtins for compatibility with the XL compiler.
+* Allow MMA builtin types in pre-P10 compilation units.
+* Add support for Return Oriented Programming (ROP) protection for 32 bit.
+* Refactored code to use more inclusive language.
+* Switched to LLD as the default linker for pre-built Linux binaries.
+* Enabled IEEE quad long double on Linux via ``PPC_LINUX_DEFAULT_IEEELONGDOUBLE``
+  in cmake config.
+  * Added ``__ibm128`` type to represent IBM double-double format, also available
+    as ``__attribute__((mode(IF)))``.
+  * ``-mfloat128`` can now be used in Linux subtargets with VSX enabled.
+* Added quadword atomic load/store support in codegen; not enabled by default.
+* Codegen improvements for splat load, byval parameter, stack lowering, etc.
+* Implemented P10 instruction scheduling model.
+* Implemented P10 instruction fusion pairs.
+* Improved handling of ``#pragma clang loop unroll_and_jam``.
+* Various bug fixes.
+
+AIX Support/improvements:
+* variadic (ellipsis) functions with C complex types are now supported.
+* Added toc-data support for AIX 64-bit.
+* Added toc-data support for read-only globals.
+* Updated default target on AIX from pwr4 to pwr7.
+* AIX 64-bit now use fast-isel for O0.
+* Added DWARF support for 32-bit XCOFF.
 
 Changes to the X86 Target
 -------------------------
 
 During this release ...
 
 * Support for ``AVX512-FP16`` instructions has been added.
 * Removed incomplete support for Intel MPX.
* llvm-objdump ``-T`` now prints symbol versions.
   (`D108097 <https://reviews.llvm.org/D108097>`_)
 * llvm-readobj: Improved printing of symbols in Windows unwind data.
 * llvm-readobj now supports ``--elf-output-style=JSON`` for JSON output and
   ``--pretty-print`` for pretty printing of this output.
   (`D114225 <https://reviews.llvm.org/D114225>`_)
 * llvm-readobj now supports several dump styles (``--needed-libs, --relocs, --syms``) for XCOFF.
 * llvm-symbolizer now supports `--debuginfod <https://llvm.org/docs/CommandGuide/llvm-symbolizer.html>`.
   (`D113717 <https://reviews.llvm.org/D113717>`_)
+* ``llvm-cov`` now accepts "allowlist" spelling for ``-name-allowlist``.
+* ``llvm-nm`` now supports XCOFF object files.
+* Added ``--needed-libs``, aux header, and symbols support in ``llvm-readobj``.
+* Added ``--symbolize-operands`` support in ``llvm-objdump``.
+* Tools that read archive files now support reading AIX big format archive files.
+* Added dump section support in ``obj2yaml``.
+* Added ``yaml2obj`` support for 64-bit XCOFF.
 
 Changes to LLDB
 ---------------------------------
 
 * A change in Clang's type printing has changed the way LLDB names array types
   (from ``int [N]`` to ``int[N]``) - LLDB pretty printer type name matching
   code may need to be updated to handle this.
 * The following commands now ignore non-address bits (e.g. AArch64 pointer