[LLVMdev] dmb ishld in AArch64

[Chengyu Song]

I'm using r223407.  Switching to a clean built on r223853, it still gives me:

    ldr x8, [x21,#8]
    stp x21, x8, [x19]
    dmb ishst
    ldr x8, [x19,#8]
    str x19, [x8]
    str x19, [x21,#8]

Thanks,
Chengyu

> On Dec 9, 2014, at 6:32 PM, Tim Northover <t.p.northover at gmail.com> wrote:
> 
> On 9 December 2014 at 15:14, Chengyu Song <csong84 at gatech.edu> wrote:
>> Errr. my fault. I patched the rcu_assign_pointer ... Let me try again.
> 
> It's looking closer now, but I still can't trigger the bug I'm afraid.
> Even disabling the load/store optimiser and fiddling with CPUs (to try
> different schedulers) just gives me what I'd expect:
> 
>        ldr     x8, [x21, #8]
>        str      x21, [x19]
>        str     x8, [x19, #8]
>        dmb ishst
>        ldr     x8, [x19, #8]
>        str      x19, [x8]
> 
> I'm not aware of any big changes in this area recently. You don't have
> any local LLVM patches or anything that could be causing the problem?
> What revision of trunk did you get it to fail on? I could try checking
> that one out.
> 
> Cheers.
> 
> Tim.