[llvm] [AArch64] Allocate two emergency spill slots for MTE to fix register … (PR #186505)

[Usama Hameed via llvm-commits]

usama54321 wrote:

Thanks for the feedback @efriedma-quic! I ended up going with your second suggestion. I am new to compiler backend work so apologies in advance if my understanding below is incorrect.

Regarding the first alternative (making the instructions clobber a temporary register): I looked into this, but TagStoreEdit::emitLoop happens after Register Allocation. My understanding is that if we add an additional early-clobber output register to the STGloop, the register allocator will never see it to spill for it.

I have implemented your second suggestion and added some tests.

https://github.com/llvm/llvm-project/pull/186505