Interesting that your build times are slower with clang. I've found on most of my projects clang is roughly 30% faster to compile in debug, but release I haven't seen a huge difference between the two.
Static analysis is a lot slower but regular clang++ is also significantly slower than g++, like a 4-5 minute build time vs 2:30 on g++.
It might have something to do with a heavy usage of templates in a few files, I don't know.
Clang's autovectorization is better in a few functions I disassembled but otherwise the generated code doesn't benchmark any faster, it's better in some places, worse in others.
But TCC is 10x faster than both of them.