Re: Current int & float overflow checking is slow.

We already know this integer overflow checking is non-standard and
compilers keep trying to optimize them out.  Our only strategy to
defeat that depends on compiler flags like -fwrapv that vary by
compiler and may or may not be working on less well tested compiler.

So if there's a nice readable and convenient way to portably use cpu
flags That would be brilliant. And I'm not too concerned if it doesn't
run on VAX.