[bluetech]

I liked this bit, using the fastest compiler for each primitive:

> ./do tries a list of compilers in compilers/c, keeping the fastest working implementation of each primitive. Before running ./do you can edit compilers/c to adjust compiler options or to try additional compilers.

[rphlx]

It is sadly necessary; 30%+ performance regressions from, say, gcc 4 to gcc 6 are not uncommon w/ vector intrinsics.