> This means that the largest int on the host must be at least half the > size of the largest int on the target. Hence, building 64-bit target > compilers on 32-bit host systems has never been a problem.
I'm not sure I'd go as far as saying "has never been a problem". It's "mostly worked", but did have optimization losses and various minor issues from time to time. There was enough of a problem that (before the days when we switched to HOST_WIDE_INT being "long long") I wanted to be sure that I used a 64-bit host since I needed to build 64-bit targets.