[llvm] [LV] Rework collectUnitStridePredicates (PR #216362)

[via llvm-commits]

github-actions[bot] wrote:

test-suite diff from 38da688c60b208a48d60b70396ac46716edc72d5...a8b5b6e982d060b298d1db0ff17e109435cb1bdc: https://github.com/llvm/llvm-project/actions/runs/32003306111/artifacts/9281827225

Statistics: https://github.com/llvm/llvm-project/actions/runs/32003306111/artifacts/9281828244

## riscv64-linux-gnu `-march=rva23u64 -O3`
| ('Program', '')    |   ('size..text', 'base') |   ('size..text', 'head') |   ('size..text', 'diff') |
|:-------------------|-------------------------:|-------------------------:|-------------------------:|
| Geomean difference |                      nan |                      nan |                        0 |
## aarch64-linux-gnu `-march=armv9-a -O3`
| ('Program', '')    |   ('size..text', 'base') |   ('size..text', 'head') |   ('size..text', 'diff') |
|:-------------------|-------------------------:|-------------------------:|-------------------------:|
| Geomean difference |                      nan |                      nan |                        0 |
## x86_64-linux-gnu `-march=x86-64-v3 -O3`
| ('Program', '')    |   ('size..text', 'base') |   ('size..text', 'head') |   ('size..text', 'diff') |
|:-------------------|-------------------------:|-------------------------:|-------------------------:|
| Geomean difference |                      nan |                      nan |                        0 |


https://github.com/llvm/llvm-project/pull/216362