[llvm] [llvm][LoongArch] Introduce LASX and LSX conversion intrinsics (PR #157818)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

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

Full details are available at: https://lab.llvm.org/buildbot/#/builders/3/builds/24436

<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 :: CodeGen/X86/sse2-intrinsics-fast-isel.ll' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/buildbot/worker/arc-folder/build/bin/llc < /buildbot/worker/arc-folder/llvm-project/llvm/test/CodeGen/X86/sse2-intrinsics-fast-isel.ll -show-mc-encoding -fast-isel -mtriple=i386-unknown-unknown -mattr=+sse2 | /buildbot/worker/arc-folder/build/bin/FileCheck /buildbot/worker/arc-folder/llvm-project/llvm/test/CodeGen/X86/sse2-intrinsics-fast-isel.ll --check-prefixes=CHECK,X86,SSE,X86-SSE
# executed command: /buildbot/worker/arc-folder/build/bin/llc -show-mc-encoding -fast-isel -mtriple=i386-unknown-unknown -mattr=+sse2
# .---command stderr------------
# | LLVM ERROR: Cannot select: intrinsic %llvm.x86.sse2.clflush
# | PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
# | Stack dump:
# | 0.	Program arguments: /buildbot/worker/arc-folder/build/bin/llc -show-mc-encoding -fast-isel -mtriple=i386-unknown-unknown -mattr=+sse2
# | 1.	Running pass 'Function Pass Manager' on module '<stdin>'.
# | 2.	Running pass 'X86 DAG->DAG Instruction Selection' on function '@test_mm_clflush'
# |  #0 0x00000000023a9188 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/buildbot/worker/arc-folder/build/bin/llc+0x23a9188)
# |  #1 0x00000000023a6095 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
# |  #2 0x00007f5530ba1630 __restore_rt sigaction.c:0:0
# |  #3 0x00007f552f8f13d7 raise (/usr/lib64/libc.so.6+0x363d7)
# |  #4 0x00007f552f8f2ac8 abort (/usr/lib64/libc.so.6+0x37ac8)
# |  #5 0x000000000072a8f7 llvm::json::operator==(llvm::json::Value const&, llvm::json::Value const&) (.cold) JSON.cpp:0:0
# |  #6 0x0000000002124459 llvm::SelectionDAGISel::CannotYetSelect(llvm::SDNode*) (/buildbot/worker/arc-folder/build/bin/llc+0x2124459)
# |  #7 0x0000000002128fca llvm::SelectionDAGISel::SelectCodeCommon(llvm::SDNode*, unsigned char const*, unsigned int) (/buildbot/worker/arc-folder/build/bin/llc+0x2128fca)
# |  #8 0x0000000000970b77 (anonymous namespace)::X86DAGToDAGISel::Select(llvm::SDNode*) X86ISelDAGToDAG.cpp:0:0
# |  #9 0x000000000211fc9f llvm::SelectionDAGISel::DoInstructionSelection() (/buildbot/worker/arc-folder/build/bin/llc+0x211fc9f)
# | #10 0x000000000212fb78 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/buildbot/worker/arc-folder/build/bin/llc+0x212fb78)
# | #11 0x0000000002133e23 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/buildbot/worker/arc-folder/build/bin/llc+0x2133e23)
# | #12 0x0000000002134915 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (/buildbot/worker/arc-folder/build/bin/llc+0x2134915)
# | #13 0x000000000211f4af llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) (/buildbot/worker/arc-folder/build/bin/llc+0x211f4af)
# | #14 0x0000000001227997 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
# | #15 0x00000000018a89eb llvm::FPPassManager::runOnFunction(llvm::Function&) (/buildbot/worker/arc-folder/build/bin/llc+0x18a89eb)
# | #16 0x00000000018a8d91 llvm::FPPassManager::runOnModule(llvm::Module&) (/buildbot/worker/arc-folder/build/bin/llc+0x18a8d91)
# | #17 0x00000000018a99a5 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/buildbot/worker/arc-folder/build/bin/llc+0x18a99a5)
# | #18 0x000000000080f5a8 compileModule(char**, llvm::LLVMContext&) llc.cpp:0:0
# | #19 0x0000000000733286 main (/buildbot/worker/arc-folder/build/bin/llc+0x733286)
# | #20 0x00007f552f8dd555 __libc_start_main (/usr/lib64/libc.so.6+0x22555)
# | #21 0x00000000008047e6 _start (/buildbot/worker/arc-folder/build/bin/llc+0x8047e6)
# `-----------------------------
# error: command failed with exit status: -6
# executed command: /buildbot/worker/arc-folder/build/bin/FileCheck /buildbot/worker/arc-folder/llvm-project/llvm/test/CodeGen/X86/sse2-intrinsics-fast-isel.ll --check-prefixes=CHECK,X86,SSE,X86-SSE
# .---command stderr------------
# | /buildbot/worker/arc-folder/llvm-project/llvm/test/CodeGen/X86/sse2-intrinsics-fast-isel.ll:399:14: error: SSE-LABEL: expected string not found in input
# | ; SSE-LABEL: test_mm_bsrli_si128:
# |              ^
# | <stdin>:170:21: note: scanning from here
# | test_mm_bslli_si128: # @test_mm_bslli_si128
# |                     ^
# | <stdin>:178:9: note: possible intended match here
# |  .globl test_mm_bsrli_si128 # 
# |         ^
...

```

</details>

https://github.com/llvm/llvm-project/pull/157818