https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81148
--- Comment #14 from Richard Biener <rguenth at gcc dot gnu.org> --- Folding -123 - (((long int) ~(x != 0) ^ 9223372036854775806) + 1) results in split_tree of (((long int) ~(x != 0) ^ 9223372036854775806) + 1) returning -((long int) ~(x != 0) ^ 9223372036854775806) and minus_lit1 == 1. The bug is obviously negating of 'var'. I don't see any way around handling var and con like lit, thus adding minus_var and minus_con and appropriately using MINUS_EXPR when associating. Bah.
