[llvm] [MIPS] Fix miscompiles consecutive half operations (PR #110199)

[via llvm-commits]

yingopq wrote:

> > Fix #97975.
> 
> This only fixes it for the MIPS architecture, so should not close the issue with "Fix".
> 
> The fix itself here looks fine to me, but I feel like the test coverage is very weak. There's just that one test, and because it's not a generated one, it omits too much information to even tell if the assembly is correct.

I would update the title and enhance the test file.

https://github.com/llvm/llvm-project/pull/110199