[llvm] [IA][RISCV] Recognize deinterleaved loads that could lower to strided segmented loads (PR #151612)

[Min-Yih Hsu via llvm-commits]

mshockwave wrote:

@Mel-Chen this patch now recognizes the pattern you listed before:
```
%gap_mask = shuffle
%condition_mask = shuffle
%group_mask = and %condition_mask, %gap_mask
%wide_load = load %ptr, %group_mask
```
And I'm working on the vp.store/masked.store counterpart of this patch

https://github.com/llvm/llvm-project/pull/151612