[llvm] [MIPS] Sign-extend subwords when expanding atomic max/min (PR #89246)

[YunQiang Su via llvm-commits]

wzssyqa wrote:


> 
> You mean `incr` is sign extended after function `MachineBasicBlock *MipsTargetLowering::emitAtomicBinaryPartword`?

I mean the caller of `test_max_16` or similar should guarantee the `1st` (count from 0, type short) of `test_max_16` to be well sign-extended.

https://github.com/llvm/llvm-project/pull/89246