On Mon, Jan 8, 2018 at 12:20 AM, Florian Weimer <f...@deneb.enyo.de> wrote: > * H. J. Lu: > >> Add -mindirect-branch-loop= option to control loop filler in call and >> return thunks generated by -mindirect-branch=. 'lfence' uses "lfence" >> as loop filler. 'pause' uses "pause" as loop filler. 'nop' uses "nop" >> as loop filler. The default is 'lfence'. > > Why is the loop needed? Doesn't ud2 or cpuid stop speculative > execution?
My understanding is that a loop works better. -- H.J.
