RFR: 8336906: C2: assert(bb->is_reachable()) failed: getting result from unreachable basicblock [v3]

[Manuel Hässig]

On Tue, 13 May 2025 11:28:30 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Manuel Hässig has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Add jsr to falls_through()
>
> src/hotspot/share/runtime/deoptimization.cpp line 845:
> 
>> 843: 
>> 844: #ifndef PRODUCT
>> 845: // Return true if the execution after the provided bytecode continues at the
> 
> Suggestion:
> 
> // Return true if the execution after the provided bytecode can continue at the
> 
> Nit: Because a `cmp_if` may or may not continue with the next bci.

I looked into that and both basic blocks following the `if_cmp` will always be reachable as far as `bb->is_reachable()` is concerned. The bytecode verification code of the `if_cmp` to check that the stack depth on both the then and else branch are the same requires both basic blocks to be reachable.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25118#discussion_r2086635527