[llvm] [X86][EVEX512] Restrict attaching EVEX512 for default CPU only, NFCI (PR #65920)

[via llvm-commits]

ronlieb wrote:

sorry for the late problem, seems our qmcpack app may have made a recent change that exposed this issue:
llc < bug.ll

llc:  llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:7536: llvm::SDValue getMemcpyLoadsAndStores(llvm::SelectionDAG&, const llvm::SDLoc&, llvm::SDValue, llvm::SDValue, llvm::SDValue, uint64_t, llvm::Align, bool, bool, llvm::MachinePointerInfo, llvm::MachinePointerInfo, const llvm::AAMDNodes&, llvm::AAResults*): Assertion `NVT.bitsGE(VT)' failed.


[repro.txt](https://github.com/llvm/llvm-project/files/13184433/repro.txt)


https://github.com/llvm/llvm-project/pull/65920