RFA: 8168996: C2 crash at postaloc.cpp:140 : assert(false) failed: unexpected yanked node

Andrew Dinn adinn at redhat.com
Mon Jan 11 09:46:00 UTC 2021

Hi Felix,

On 11/01/2021 06:29, Yangfei (Felix) wrote:
> Sorry, I should have mentioned more details about the diagnosis for
> 8u in my previous mail.
> . . .
> With that we managed to get the C2 graph after "Optimized finished"
> phase.  The subgraph looks like:
>  LoadN  -->  DecodeN  --> MemBarAcquire
> Here, the MemBarAcquire node from a volatile object field was keeping
> the otherwise dead LoadN nodes alive. But we don't have a Phi in
> between. This is slight different with the C2 graph in the original
> RFR thread. I think this does not affect the application of the
> original fix.  Is this enough to validate the 8u backport?

That's more than enough to approve this as the right fix for the right 

Nice work ;-)


Andrew Dinn
Red Hat Distinguished Engineer
Red Hat UK Ltd
Registered in England and Wales under Company Registration No. 03798903
Directors: Michael Cunningham, Michael ("Mike") O'Neill

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