RFR: 8252583: Make PhiNode::is_copy() debug only [v2]

[Vladimir Kozlov]

On Mon, 21 Sep 2020 12:32:36 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

>> Roberto Castañeda Lozano has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Fix spacing in touched lines
>
> Changes requested by thartmann (Reviewer).

Sorry, I am not sure this is better than original code where assert is in one place - in PhiNode::is_copy().
The method is in .hpp file and is inlined - NULL check will be eliminated. It will only be executed in slowdebug build.
May be we should "bite the bullet" and remove this method at all - we don't hit the assert in years.
We can replace is_copy() check with assert in PhiNode::Ideal() - that should be enough to guarantee that we don't
create Phi with NULL control edge.

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PR: https://git.openjdk.java.net/jdk/pull/275