If it is needed to pass the same option from driver to both host and device compilers, then it must be added two-times - see clang/lib/Driver/ToolChains/Clang.cpp, for example:
4124:CmdArgs.push_back("-fsycl");
...
6150:CmdArgs.push_back("-fsycl");

This is quite error prone and inconvenient - should be automated: option placed in one place, driver does the duplication itself.

load and store functions are not implemented for vec class now.

Just an FYI whilst I was trawling through the ROCm GitHub page:

https://rocmdocs.amd.com/en/latest/Programming_Guides/Programming-Guides.html#

The cl_ types are not needed in general, however they should still be kept in the OpenCL C interop sample code.

Turn on -fstrict-aliasing -Wstrict-aliasing.