On Tue, Oct 10, 2023 at 8:26 PM Jeff Law wrote:
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>
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> On 10/10/23 18:24, Andrew Waterman wrote:
> > I remembered another concern since we discussed this patch privately.
> > Using ra for long calls results in a sequence that will corrupt the
> > return-address stack.
> Yup. We've actually got d
On 10/10/23 18:24, Andrew Waterman wrote:
I remembered another concern since we discussed this patch privately.
Using ra for long calls results in a sequence that will corrupt the
return-address stack.
Yup. We've actually got data on that internally, it's not showing up in
a significant way
I remembered another concern since we discussed this patch privately.
Using ra for long calls results in a sequence that will corrupt the
return-address stack. Corrupting the RAS is potentially more costly
than mispredicting a branch, since it can result in a cascading
sequence of mispredictions a
Ventana has had a variant of this patch from Andrew W. in its tree for
at least a year. I'm dusting it off and submitting it on Andrew's behalf.
There's multiple approaches we could be using here.
First we could make $ra fixed and use it as the scratch register for the
long branch sequence
