https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69320
--- Comment #8 from Jeffrey A. Law <law at redhat dot com> --- Jakub. I'll certainly backtest against the referenced BZs While the fix is trivial, I'm seriously considering just turning the exploitation of ranges off for gcc-6. It didn't help as much as I had wanted in the path splitting bits, so it's not terribly important for this release.