[llvm] [LV] Always try to use fixed VF for low TC loops if no epilogue allowed. (PR #226318)

[via llvm-commits]

github-actions[bot] wrote:

test-suite diff from 9dcb4291cea195b9f0941d39540a4f2ccb9ff6bd...a42a17e1ab5ce9f22d27324be025b695f7c22e52: https://github.com/llvm/llvm-project/actions/runs/36192619391/artifacts/10890069908

Statistics: https://github.com/llvm/llvm-project/actions/runs/36192619391/artifacts/10890059934

## riscv64-linux-gnu `-march=rva23u64 -O3`
| ('Program', '')    |   ('size..text', 'base') |   ('size..text', 'head') |   ('size..text', 'diff') |
|:-------------------|-------------------------:|-------------------------:|-------------------------:|
| Geomean difference |                      nan |                      nan |             -6.42885e-05 |
## 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/226318