Displaying 2 results from an estimated 2 matches for "_mm_lfence".
2020 Jul 28
2
_mm_lfence in both pathes of an if/else are hoisted by SimplfyCFG potentially breaking use as a speculation barrier
_mm_lfence was originally documented as a load fence. But in light of
speculative execution vulnerabilities it has started being advertised as a
way to prevent speculative execution. Current Intel Software Development
Manual documents it as "Specifically, LFENCE does not execute until all
prior instructi...
2020 Aug 09
2
_mm_lfence in both pathes of an if/else are hoisted by SimplfyCFG potentially breaking use as a speculation barrier
...dependency -- and it kind of looks
> like it from where I stand -- then perhaps this is something to
> consider more seriously?
>
> Cheers,
> Nicolai
>
> On Wed, Jul 29, 2020 at 1:30 AM Craig Topper via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
> >
> > _mm_lfence was originally documented as a load fence. But in light of speculative execution vulnerabilities it has started being advertised as a way to prevent speculative execution. Current Intel Software Development Manual documents it as "Specifically, LFENCE does not execute until all prior instructi...