[llvm] [LoongArch] Custom lower vecreduce. (PR #155196)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-aarch64-darwin` running on `doug-worker-5` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/26499

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli -jit-kind=orc-lazy -compile-threads=2 -thread-entry hello /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll | /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll # RUN: at line 1
+ /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli -jit-kind=orc-lazy -compile-threads=2 -thread-entry hello /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll
+ /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli -jit-kind=orc-lazy -compile-threads=2 -thread-entry hello /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll
 #0 0x00000001039c043c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100f0843c)
 #1 0x00000001039be1ec llvm::sys::RunSignalHandlers() (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100f061ec)
 #2 0x00000001039c0f3c SignalHandler(int, __siginfo*, void*) (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100f08f3c)
 #3 0x0000000182f63584 (/usr/lib/system/libsystem_platform.dylib+0x18047b584)
 #4 0x0000010103519ba0
 #5 0x00000001035250e4 llvm::orc::ExecutionSession::removeJITDylibs(std::__1::vector<llvm::IntrusiveRefCntPtr<llvm::orc::JITDylib>, std::__1::allocator<llvm::IntrusiveRefCntPtr<llvm::orc::JITDylib>>>) (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100a6d0e4)
 #6 0x0000000103524e94 llvm::orc::ExecutionSession::endSession() (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100a6ce94)
 #7 0x00000001035b1058 llvm::orc::LLJIT::~LLJIT() (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100af9058)
 #8 0x00000001035b59e4 llvm::orc::LLLazyJIT::~LLLazyJIT() (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100afd9e4)
 #9 0x0000000102ac2a44 runOrcJIT(char const*) (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x10000aa44)
#10 0x0000000102abe174 main (/Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/lli+0x100006174)
#11 0x0000000182ba7154
FileCheck error: '<stdin>' is empty.
FileCheck command line:  /Volumes/ExternalSSD/buildbot-root/aarch64-darwin/build/bin/FileCheck /Users/buildbot/buildbot-root2/aarch64-darwin/llvm-project/llvm/test/ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll

--

********************


```

</details>

https://github.com/llvm/llvm-project/pull/155196