Does icc support attribute((ms_abi)) these days? Without that it is virtually impossible. There might be more less global but still blocking issues coming up.
In general, I'd suggest to try to build upstream Wine with it first. Also, you might find that while Intel Compiler provides remarkable optimization in many scenarios it might be hard to find a case when it gives measurable performance improvement in Wine case.
Yes, icx which uses clang supports it.
I tried to build wine used by proton with icx and it actually works, but on the winegcc stage there occur mix with gcc and some link flags error. It needs refactoring of winegcc (at least) to allow for such compilation
Nothing extracted yet.
On my pc Intel C++ does a very excellent job and i want a way to build this tool via it. Generally speaking icx is mostly (or slightly faster) gcc in single task but much better in multi-tasking. (Though some benchmarks show it is slower gcc)