https://gcc.gnu.org/bugzilla/show_bug.cgi?id=24021
--- Comment #13 from Andrew Macleod <amacleod at redhat dot com> --- > etc. which would be great if it could use frange. Though, I think we also > run here into the problem that match.pd right now avoids the ranger because > it could reliably only allow walks from uses to SSA_NAME_DEF_STMTs and not > the other direction. That only happens with pointers and the non-null property right now, and even that is going away to start GCC13. I have the prototype underway now. . > One thing to consider is that at runtime, not all arithmetics might be as > precise as what mpfr does at compile time, so in some cases it should expect > a few ulps or maybe even more than that as possible errors (especially for > library functions). And also take into account different rounding modes if > user wants that to be honored. > We'll leave those to the experts :-) > As for exceptions, I guess one thing is that ranger computes ranges and > another thing is that optimization based on that will sometimes need to punt > if it could optimize away visible side-effects the user cares about. yeah, like with no-delete-null-pointer, there may be flag checking required for some things.