RFR: 8353341: C2: removal of a Mod[DF]Node crashes when the node is already dead [v2]

[Marc Chevalier]

On Wed, 2 Apr 2025 07:41:01 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

>> Marc Chevalier has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Address review comments
>
> src/hotspot/share/opto/divnode.cpp line 1522:
> 
>> 1520:   bool result_is_unused = proj_out_or_null(TypeFunc::Parms) == nullptr;
>> 1521:   bool is_dead = proj_out_or_null(TypeFunc::Control) == nullptr;
>> 1522:   if (result_is_unused && !is_dead) {
> 
> Might be easier to read when it's flipped to avoid negation with `!` but I leave it up to you to decide which one you prefer :-)
> 
>   bool not_dead = proj_out_or_null(TypeFunc::Control) != nullptr;
>   if (result_is_unused && not_dead) {

I'd agree if I wrote `!not_dead`. But between writing `! a_positive_property` and `a_negative_property`, I'm much less decided.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24375#discussion_r2024275097