https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107569
--- Comment #26 from Jakub Jelinek <jakub at gcc dot gnu.org> --- (In reply to Aldy Hernandez from comment #24) > If you single step from there on, we run into: > > if (gimple_stmt_nonnegative_warnv_p (call, &strict_overflow_p)) > r.set_nonnegative (type); > else if (gimple_call_nonnull_result_p (call) > || gimple_call_nonnull_arg (call)) > r.set_nonzero (type); > else > r.set_varying (type); > > IIRC, we had some discussion upstream about the meaning of set_nonnegative, > and we all agreed that nuking -NAN was the right thing. Neat, huh? :) Is this done only for statements for which there isn't a ranges handler? If so, given the IEEE 754 non-guarantee of NAN signs except for copy, abs, copysign and negate I'd say that we should have a ranges handler for all those ops and for anything else assume NAN sign is VARYING, including the above spot. As for signed zeros in -fsigned-zeros (default) mode, wonder if we e.g. don't say sqrt is nonnegative (even when sqrt (-0.0) is -0.0).
