LLVM(LoongArch64): some simd spec tests crash in LLVM

[marxin]

Apparently, the following tests crash when LLVM emits code:

     SIGSEGV [   0.271s] wasmer-workspace::compilers wast::spec::simd::simd_f32x4::llvm::llvm
     SIGSEGV [   0.181s] wasmer-workspace::compilers wast::spec::simd::simd_f64x2::llvm::llvm
     SIGSEGV [   0.082s] wasmer-workspace::compilers wast::spec::simd::simd_splat::llvm::llvm
     SIGSEGV [   0.421s] wasmer-workspace::compilers wast::spec::simd::simd_load::llvm::llvm
     SIGSEGV [   0.338s] wasmer-workspace::compilers wast::spec::simd_f32x4::llvm::llvm
     SIGSEGV [   0.186s] wasmer-workspace::compilers wast::spec::simd_f64x2::llvm::llvm
     SIGSEGV [   0.364s] wasmer-workspace::compilers wast::spec::simd_load::llvm::llvm
     SIGSEGV [   0.261s] wasmer-workspace::compilers wast::spec::simd_splat::llvm::llvm

Back-trace:

(gdb) bt
#0  0x00007fffed7eed40 in llvm::SelectionDAG::ReplaceAllUsesWith(llvm::SDNode*, llvm::SDValue const*) () from /lib/libLLVM.so.21.1
#1  0x00007fffed5bec5c in ?? () from /lib/libLLVM.so.21.1
#2  0x00007fffed5d8ae0 in ?? () from /lib/libLLVM.so.21.1
#3  0x00007fffed5e5114 in ?? () from /lib/libLLVM.so.21.1
#4  0x00007fffed5e8384 in llvm::SelectionDAG::Legalize() () from /lib/libLLVM.so.21.1
#5  0x00007fffed817a10 in llvm::SelectionDAGISel::CodeGenAndEmitDAG() () from /lib/libLLVM.so.21.1
#6  0x00007fffed819d90 in llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) () from /lib/libLLVM.so.21.1
#7  0x00007fffed81b674 in llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) () from /lib/libLLVM.so.21.1
#8  0x00007fffed815250 in llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) () from /lib/libLLVM.so.21.1
#9  0x00007fffecfd352c in llvm::MachineFunctionPass::runOnFunction(llvm::Function&) () from /lib/libLLVM.so.21.1
#10 0x00007fffecb4501c in llvm::FPPassManager::runOnFunction(llvm::Function&) () from /lib/libLLVM.so.21.1
#11 0x00007fffecb45540 in llvm::FPPassManager::runOnModule(llvm::Module&) () from /lib/libLLVM.so.21.1
#12 0x00007fffecb44674 in llvm::legacy::PassManagerImpl::run(llvm::Module&) () from /lib/libLLVM.so.21.1
#13 0x000055555556d50c in ?? ()
#14 0x0000555555561eb4 in main ()

Upstream issue: llvm/llvm-project#174606
CC: @heiher @SixWeining