RFR: 8290451: Incorrect result when switching to C2 OSR compilation from C1 [v2]

[Tobias Hartmann]

On Mon, 29 Aug 2022 09:12:01 GMT, Roland Westrelin <roland at openjdk.org> wrote:

>> In BadStateAtLongCmp.test(), the field increment is between the lcmp
>> and iflt bytecodes that implement the loop exit condition (handcrafted
>> bytecodes required as such a sequence is not generated by javac). When
>> compiled by C1, lcmp+iflt is canonicalized to a single If and it
>> captures the state of the lcmp bytecode. Tiered compilation attaches
>> the state to a deoptimization call to switch to an OSR
>> compilation. That state causes the field increment to be reexecuted
>> when the switch to a C2 method occurs at the backbranch. Proposed fix
>> is to use the state at the iflt instead.
>
> Roland Westrelin has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:
> 
>  - change class file verson
>  - Merge branch 'master' into JDK-8290451
>  - comment
>  - fix
>  - test

Marked as reviewed by thartmann (Reviewer).

-------------

PR: https://git.openjdk.org/jdk/pull/9938