[11] RFR(XS): 8202179: Compilation fails with assert(n->is_expensive()) failed: expensive nodes with non-null control here only

[Vladimir Kozlov]

Hi Tobias,

Should we also check in(0) for NULL in Node::is_unreachable() ? I know 
that is called only for expensive nodes *now* but still it should check 
for 0.

Thanks,
Vladimir

On 4/26/18 12:05 AM, Tobias Hartmann wrote:
> Hi,
> 
> please review the following patch:
> https://bugs.openjdk.java.net/browse/JDK-8202179
> http://cr.openjdk.java.net/~thartmann/8202179/webrev.00/
> 
> Expensive nodes have control inputs to prevent GVN from commoning them which may cause more frequent
> execution (see comment of PhaseIdealLoop::process_expensive_nodes()).
> Compile::cleanup_expensive_nodes() assumes no expensive nodes are added after parsing and removes
> the control input if there's only a single copy of a node. ConvD2FNode::Ideal() then creates a new
> SqrtFNode with the control of the input SqrtDNode (which is NULL).
> 
> We should only treat the SqrtFNode as expensive if the control input is not NULL.
> 
> I was only able to reproduce this with replay compilation and a customer application.
> 
> All tests pass.
> 
> Thanks,
> Tobias
>