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.

It'd be nice to get performance warnings in certain cases, such as

• repeated use of non-contiguous ndarrays leads to repeated conversion to DAAL tables
• different input types than algorithm's fptype waste a lot of time in conversion