Compilers have bugs of course, but I would be very surprised if any workload worth billions of dollars has a 10x problem. All the FAANGs spend millions of dolla

Compilers have bugs of course, but I would be very surprised if any workload worth billions of dollars has a 10x problem. All the FAANGs spend millions of dollars on their respective compiler groups, and it is their job to profile and root out such problems. Often they find fixes that improve this or that internal workload by 0.2% and consider that a big win.