RFR: 8334647: C2: CastII added by PhaseIdealLoop::add_template_assertion_predicate() should have control [v2]

[Roland Westrelin]

On Mon, 24 Jun 2024 10:33:50 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

> Just thought about it again. What about ensuring that all `ConstraintCastNode` always set a control? I've had a quick look and it seems that we only have one `CastPP` where we do not set a control input. AFAICT, all other nodes set a control:
> 
> https://github.com/openjdk/jdk/blob/ca5a438e5a4612c66f70c70a9d425eca0e49e84d/src/hotspot/share/opto/vector.cpp#L491

Mandating control on all `ConstraintCastNode` sounds reasonable but I have no idea what control would make sense for the case above so maybe it's too constraining to always have to set the control.

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PR Comment: https://git.openjdk.org/jdk/pull/19808#issuecomment-2188739512