Is -O2 supported for world?

[Damian Gerow]

I'm a little fuzzy on whether -O2 is supported for world or not: I seem to
remember on x86 it is, but the only references I've seen to amd64 were
speaking about ports.

Is -O2 optimization supported in amd64?  It most definitely doesn't work:

    /usr/src/lib/libc/i386/sys/_amd64_get_fsbase.c: In function `_amd64_get_fsbase':
    /usr/src/lib/libc/i386/sys/_amd64_get_fsbase.c:40: warning: dereferencing type-punned pointer will break strict-aliasing rules

without -fno-strict-aliasing.  Not that I have any serious desire to run
with -O2, just curious.

  - Damian