https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63384
--- Comment #3 from Andi Kleen <andi-gcc at firstfloor dot org> --- It loops (forever?) on this in sched2: Scheduling on fences: (uid:28;seqno:7;) Fence 28[2] has not changed Scheduling on fences: (uid:28;seqno:7;) Fence 28[2] has not changed Scheduling on fences: (uid:28;seqno:7;) Fence 28[2] has not changed Scheduling on fences: (uid:28;seqno:7;) Fence 28[2] has not changed Scheduling on fences: (uid:28;seqno:7;) Fence 28[2] has not changed Scheduling on fences: (uid:28;seqno:7;) Fence 28[2] has not changed Scheduling on fences: (uid:28;seqno:7;) Fence 28[2] has not changed Scheduling on fences: (uid:28;seqno:7;) Fence 28[2] has not changed