[llvm] [ARM] Prefer MUL to MULS on some implementations (PR #112540)

[Albert Huang via llvm-commits]

AlbertHuang-CPU wrote:

If the mul instruction is in the IT block, there won't be MULS. Is this useful as a condition to help judging shrink or not?
Why only m33 added with this feature? Do we need to add it to the ProcessorModel of other other Armv8-M CPUs?

https://github.com/llvm/llvm-project/pull/112540