[libclc] Fix memory fence scope mapping for OpenCL (#170542)
The function `__opencl_get_memory_scope` incorrectly assumed that the
Clang built-in `__MEMORY_SCOPE_*` macros defined as bitmasks, while they
are actually defined as distinct integer values. This led to incorrect
mapping of OpenCL memory fence flags to LLVM memory scopes, causing
issues in generated code.
The fix involves updating the `__opencl_get_memory_scope` function to
return the correct `__MEMORY_SCOPE_*` values based on the provided
`cl_mem_fence_flags`. Additionally, the `__opencl_get_memory_semantics`
and the `__opencl_get_memory_scope` functions are marked as `static`
to avoid potential multiple definition issues during linking.
llvm-project
b8a5888d - [libclc] Fix memory fence scope mapping for OpenCL (#170542)
