RFR(S): 8239367: RunThese30M.java failed due to "assert(false) failed: graph should be schedulable"
Tobias Hartmann
tobias.hartmann at oracle.com
Tue Mar 3 07:55:51 UTC 2020
Hi Roland,
that looks good to me and I'm actually glad to get rid of find_bottom_mem.
Best regards,
Tobias
On 02.03.20 10:15, Roland Westrelin wrote:
>
> http://cr.openjdk.java.net/~roland/8239367/webrev.00/
>
> The code to wire memory when the new SubTypeCheck node is expanded is
> broken. It assumes that the first bottom memory it encounters when
> walking through the graph dominates the point where the SubTypeCheck is
> expanded. That doesn't hold. In this particular case, the SubTypeCheck
> node is expanded right after a region that has several memory Phis all
> feeding into a MergeMem. The find_bottom_mem() method doesn't see bottom
> memory at the region so picks one of the Region's edge and looks for
> bottom memory there. It finds a bottom memory Phi which doesn't dominate
> the SubTypeCheck node. I think fixing find_bottom_mem() is too
> complicated and propose we go with Vladimir I's suggestion of using
> immutable memory instead:
>
> https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2020-February/037022.html
>
> Roland.
>
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