[llvm] Reland "[LoopVectorizer] Add support for partial reductions" (PR #120721)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-aarch64-windows` running on `linaro-armv8-windows-msvc-05` while building `llvm` at step 6 "test".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/141/builds/4973

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test) failure: build (failure)
...
PASS: lldb-api :: tools/lldb-server/TestGdbRemoteKill.py (1178 of 2057)
PASS: lldb-api :: tools/lldb-server/TestGdbRemoteLaunch.py (1179 of 2057)
UNSUPPORTED: lldb-api :: tools/lldb-server/TestGdbRemotePlatformFile.py (1180 of 2057)
PASS: lldb-api :: tools/lldb-server/TestGdbRemoteModuleInfo.py (1181 of 2057)
PASS: lldb-api :: tools/lldb-server/TestGdbRemoteRegisterState.py (1182 of 2057)
UNSUPPORTED: lldb-api :: tools/lldb-server/TestGdbRemoteSaveCore.py (1183 of 2057)
UNSUPPORTED: lldb-api :: tools/lldb-server/TestGdbRemoteSingleStep.py (1184 of 2057)
PASS: lldb-api :: tools/lldb-server/TestGdbRemoteProcessInfo.py (1185 of 2057)
PASS: lldb-api :: tools/lldb-server/TestGdbRemoteThreadsInStopReply.py (1186 of 2057)
PASS: lldb-api :: tools/lldb-server/TestGdbRemote_vCont.py (1187 of 2057)
FAIL: lldb-api :: tools/lldb-server/TestGdbRemote_qThreadStopInfo.py (1188 of 2057)
******************** TEST 'lldb-api :: tools/lldb-server/TestGdbRemote_qThreadStopInfo.py' FAILED ********************
Script:
--
C:/Users/tcwg/scoop/apps/python/current/python.exe C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/llvm-project/lldb\test\API\dotest.py -u CXXFLAGS -u CFLAGS --env LLVM_LIBS_DIR=C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./lib --env LLVM_INCLUDE_DIR=C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/include --env LLVM_TOOLS_DIR=C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin --arch aarch64 --build-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/lldb-test-build.noindex --lldb-module-cache-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/lldb-test-build.noindex/module-cache-lldb\lldb-api --clang-module-cache-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/lldb-test-build.noindex/module-cache-clang\lldb-api --executable C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin/lldb.exe --compiler C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin/clang.exe --dsymutil C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin/dsymutil.exe --make C:/Users/tcwg/scoop/shims/make.exe --llvm-tools-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin --lldb-obj-root C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/tools/lldb --lldb-libs-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./lib --skip-category=watchpoint C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\llvm-project\lldb\test\API\tools\lldb-server -p TestGdbRemote_qThreadStopInfo.py
--
Exit Code: 1

Command Output (stdout):
--
lldb version 20.0.0git (https://github.com/llvm/llvm-project.git revision c858bf620c3ab2a4db53e84b9365b553c3ad1aa6)
  clang revision c858bf620c3ab2a4db53e84b9365b553c3ad1aa6
  llvm revision c858bf620c3ab2a4db53e84b9365b553c3ad1aa6
Skipping the following test categories: ['watchpoint', 'libc++', 'libstdcxx', 'dwo', 'dsym', 'gmodules', 'debugserver', 'objc', 'fork', 'pexpect']


--
Command Output (stderr):
--
UNSUPPORTED: LLDB (C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\build\bin\clang.exe-aarch64) :: test_qThreadStopInfo_only_reports_one_thread_stop_reason_during_interrupt_debugserver (TestGdbRemote_qThreadStopInfo.TestGdbRemote_qThreadStopInfo.test_qThreadStopInfo_only_reports_one_thread_stop_reason_during_interrupt_debugserver) (test case does not fall in any category of interest for this run) 

XFAIL: LLDB (C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\build\bin\clang.exe-aarch64) :: test_qThreadStopInfo_only_reports_one_thread_stop_reason_during_interrupt_llgs (TestGdbRemote_qThreadStopInfo.TestGdbRemote_qThreadStopInfo.test_qThreadStopInfo_only_reports_one_thread_stop_reason_during_interrupt_llgs)

UNSUPPORTED: LLDB (C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\build\bin\clang.exe-aarch64) :: test_qThreadStopInfo_works_for_multiple_threads_debugserver (TestGdbRemote_qThreadStopInfo.TestGdbRemote_qThreadStopInfo.test_qThreadStopInfo_works_for_multiple_threads_debugserver) (test case does not fall in any category of interest for this run) 

FAIL: LLDB (C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\build\bin\clang.exe-aarch64) :: test_qThreadStopInfo_works_for_multiple_threads_llgs (TestGdbRemote_qThreadStopInfo.TestGdbRemote_qThreadStopInfo.test_qThreadStopInfo_works_for_multiple_threads_llgs)

======================================================================

FAIL: test_qThreadStopInfo_works_for_multiple_threads_llgs (TestGdbRemote_qThreadStopInfo.TestGdbRemote_qThreadStopInfo.test_qThreadStopInfo_works_for_multiple_threads_llgs)

----------------------------------------------------------------------

Traceback (most recent call last):

  File "C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\llvm-project\lldb\packages\Python\lldbsuite\test\tools\lldb-server\gdbremote_testcase.py", line 48, in test_method

    return attrvalue(self)


```

</details>

https://github.com/llvm/llvm-project/pull/120721