On Mon, Sep 23, 2013 at 1:42 PM, Oleg Endo <oleg.endo@xxxxxxxxxxx> wrote: > On Mon, 2013-09-23 at 13:38 -0600, Dave Allured - NOAA Affiliate wrote: >> >> I believe the CPU overflow flag is updated after most integer >> arithmetic instructions. Does GCC have any facility for checking this >> flag after each integer operation? This would be a runtime check, of >> course, not a compile time check. > > See -ftrapv option. Although trapping math is not supported on every > target properly. > E.g. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35412 > or SH related http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54272 Oleg, thanks for the tip. "-ftrapv is seriously broken and nobody wants to fix it", and that was 5.6 years ago. Too bad, it seems like a useful thing when you need it. I use gcc's -ffpe-trap routinely to guard fortran floating point stuff, and it has done many favors for me. --Dave
