[clang] [clang] Increase VecLib bitfield size to 4 bits in CodeGenOptions.def (PR #108804)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-win-fast` running on `as-builder-3` while building `clang` at step 5 "cmake-configure".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/2/builds/7016

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (cmake-configure) failure: cmake (failure)
...

  LLVM's build system enforces that all source files are added to a build
  target, that exactly one build target exists in each directory, and that
  this target lists all files in that directory.  If you want multiple
  targets in the same directory, add PARTIAL_SOURCES_INTENDED to the target
  specification, though it is discouraged.

  Please update
  C:/buildbot/as-builder-3/llvm-clang-x86_64-win-fast/llvm-project/clang/unittests/CodeGen/CMakeLists.txt


Call Stack (most recent call first):
  cmake/modules/LLVMProcessSources.cmake:62 (llvm_check_source_file_list)
  cmake/modules/AddLLVM.cmake:997 (llvm_process_sources)
  cmake/modules/AddLLVM.cmake:1052 (generate_llvm_objects)
  cmake/modules/AddLLVM.cmake:1742 (add_llvm_executable)
  C:/buildbot/as-builder-3/llvm-clang-x86_64-win-fast/llvm-project/clang/unittests/CMakeLists.txt:23 (add_unittest)
  C:/buildbot/as-builder-3/llvm-clang-x86_64-win-fast/llvm-project/clang/unittests/CodeGen/CMakeLists.txt:7 (add_clang_unittest)


-- BugpointPasses ignored -- Loadable modules not supported on this platform.
-- Google Benchmark version: v0.0.0, normalized to 0.0.0
-- Looking for shm_open in rt
-- Looking for shm_open in rt - not found
-- Performing Test HAVE_CXX_FLAG_EHS_
-- Performing Test HAVE_CXX_FLAG_EHS_ - Success
-- Performing Test HAVE_CXX_FLAG_EHA_
-- Performing Test HAVE_CXX_FLAG_EHA_ - Success
-- Compiling and running to test HAVE_GNU_POSIX_REGEX
-- Performing Test HAVE_GNU_POSIX_REGEX -- failed to compile
-- Compiling and running to test HAVE_POSIX_REGEX
-- Performing Test HAVE_POSIX_REGEX -- failed to compile
-- Compiling and running to test HAVE_STEADY_CLOCK
CMake Warning at C:/buildbot/as-builder-3/llvm-clang-x86_64-win-fast/llvm-project/third-party/benchmark/CMakeLists.txt:319 (message):
  Using std::regex with exceptions disabled is not fully supported


-- Performing Test HAVE_STEADY_CLOCK -- success
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Failed
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - not found
-- Found Threads: TRUE  
-- Compiling and running to test HAVE_PTHREAD_AFFINITY
-- Performing Test HAVE_PTHREAD_AFFINITY -- failed to compile
-- Configuring incomplete, errors occurred!
See also "C:/buildbot/as-builder-3/llvm-clang-x86_64-win-fast/build/CMakeFiles/CMakeOutput.log".
See also "C:/buildbot/as-builder-3/llvm-clang-x86_64-win-fast/build/CMakeFiles/CMakeError.log".

```

</details>

https://github.com/llvm/llvm-project/pull/108804