https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81797
--- Comment #9 from Misty De Meo <misty at brew dot sh> --- My VM has two cores, and repros this problem. I reported this to Apple, who assigned the bug ID rdar://33924943. It was reported to me that Apple engineers believed it was fixed in the latest beta, but it is still reproducing.
