[clang] [llvm] [AArch64][clang][llvm] Add ACLE `stshh` atomic store builtin (PR #181386)

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github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Windows-->
# :window: Windows x64 Test Results

* 130852 tests passed
* 3445 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### Clang
<details>
<summary>Clang.CodeGen/AArch64/pcdphint-atomic-store.c</summary>

```
Exit Code: 2

Command Output (stdout):
--
# RUN: at line 1
c:\_work\llvm-project\llvm-project\build\bin\clang.exe -cc1 -internal-isystem C:\_work\llvm-project\llvm-project\build\lib\clang\23\include -nostdsysteminc -triple aarch64-none-linux-gnu -target-feature +pcdphint -D__ARM_FEATURE_PCDPHINT -emit-llvm -o - C:\_work\llvm-project\llvm-project\clang\test\CodeGen\AArch64\pcdphint-atomic-store.c | c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe C:\_work\llvm-project\llvm-project\clang\test\CodeGen\AArch64\pcdphint-atomic-store.c
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\clang.exe' -cc1 -internal-isystem 'C:\_work\llvm-project\llvm-project\build\lib\clang\23\include' -nostdsysteminc -triple aarch64-none-linux-gnu -target-feature +pcdphint -D__ARM_FEATURE_PCDPHINT -emit-llvm -o - 'C:\_work\llvm-project\llvm-project\clang\test\CodeGen\AArch64\pcdphint-atomic-store.c'
# .---command stderr------------
# | C:\_work\llvm-project\llvm-project\clang\test\CodeGen\AArch64\pcdphint-atomic-store.c:6:3: error: cannot compile this builtin function yet
# |     6 |   __arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 0);
# |       |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# | C:\_work\llvm-project\llvm-project\build\lib\clang\23\include\arm_acle.h:846:3: note: expanded from macro '__arm_atomic_store_with_stshh'
# |   846 |   __builtin_arm_atomic_store_with_stshh((ptr), (data), (memory_order), (ret))
# |       |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# | 1 error generated.
# `-----------------------------
# error: command failed with exit status: 1
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe' 'C:\_work\llvm-project\llvm-project\clang\test\CodeGen\AArch64\pcdphint-atomic-store.c'
# .---command stderr------------
# | FileCheck error: '<stdin>' is empty.
# | FileCheck command line:  c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe C:\_work\llvm-project\llvm-project\clang\test\CodeGen\AArch64\pcdphint-atomic-store.c
# `-----------------------------
# error: command failed with exit status: 2

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/181386