[llvm] [LV][RISCV] Add explicit LMUL controls via computeFeasibleMaxVF (PR #193091)

[via llvm-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Linux-->
# :penguin: Linux x64 Test Results

* 173127 tests passed
* 3221 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### Clang
<details>
<summary>Clang.SemaTemplate/concepts-out-of-line-def.cpp</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
/home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/clang -cc1 -internal-isystem /home/gha/actions-runner/_work/llvm-project/llvm-project/build/lib/clang/23/include -nostdsysteminc -std=c++20 -Wno-c++26-extensions -verify /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/SemaTemplate/concepts-out-of-line-def.cpp
# executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/clang -cc1 -internal-isystem /home/gha/actions-runner/_work/llvm-project/llvm-project/build/lib/clang/23/include -nostdsysteminc -std=c++20 -Wno-c++26-extensions -verify /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/SemaTemplate/concepts-out-of-line-def.cpp
# .---command stderr------------
# | error: 'expected-error' diagnostics seen but not expected: 
# |   File /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/SemaTemplate/concepts-out-of-line-def.cpp Line 854: out-of-line definition of 'buggy' does not match any declaration in 'PackIndexExpr::TplClass<int>'
# | error: 'expected-note' diagnostics seen but not expected: 
# |   File /home/gha/actions-runner/_work/llvm-project/llvm-project/clang/test/SemaTemplate/concepts-out-of-line-def.cpp Line 845: TplClass defined here
# | 2 errors generated.
# `-----------------------------
# error: command failed with exit status: 1

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/193091