[llvm] [MVT][TableGen] Extend Machine Value Type to `uint16_t` (PR #99657)

[Brandon Wu via llvm-commits]

4vtomat wrote:

> > > Why are there decreases of total bytes and memory usage? I suppose it should increase?
> > > And please print a comment about the real MVT name since we miss it after VBR encoding.
> > 
> > 
> > Total bytes of array actually increases especially for `RISCV`. For runtime memory, I think it's maybe because `SelectionDAG` only exists for very short period of time and the memory usage of `SelectionDAG` is not the bottleneck in the first place?
> 
> I don't think patch will have much if any effect on the runtime memory usage SelectionDAG. SelectionDAG runtime memory usage is more directly affected by `MVT::VALUETYPE_SIZE` which is not changed by this patch.

Correct, I just changed `MVT::VALUETYPE_SIZE` to 2^16 - 1 and measure the memory again, it increase to over 100 times bigger.

https://github.com/llvm/llvm-project/pull/99657