RFR: JDK-8319256: Print more diagnostic information when an unexpected user is found in a Phi [v2]

[Tobias Hartmann]

On Mon, 6 Nov 2023 18:26:52 GMT, Cesar Soares Lucas <cslucas at openjdk.org> wrote:

>> Can I please get some review on this PR to:
>> 
>> - Add more verification around the implementation of reduce allocation merges.
>> - Print more diagnostic information when an unexpected situation is encountered.
>> 
>> Testing: Linux x64 tier1-4, Renaissance, Dacapo and SpecJBB.
>
> Cesar Soares Lucas has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Address PR feedback: ifdefs.

Looks good to me.

src/hotspot/share/opto/c2_globals.hpp line 471:

> 469:                                                                             \
> 470:   notproduct(bool, TraceReduceAllocationMerges, false,                      \
> 471:           "Trace decision for simplifying allocation merges.")              \

Suggestion:

             "Trace decision for simplifying allocation merges.")           \

src/hotspot/share/opto/c2_globals.hpp line 473:

> 471:           "Trace decision for simplifying allocation merges.")              \
> 472:                                                                             \
> 473:   develop(bool, VerifyReduceAllocationMerges , true,                        \

Suggestion:

  develop(bool, VerifyReduceAllocationMerges , true,                        \

Suggestion:

  develop(bool, VerifyReduceAllocationMerges, true,                         \

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Marked as reviewed by thartmann (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/16465#pullrequestreview-1719690730
PR Review Comment: https://git.openjdk.org/jdk/pull/16465#discussion_r1386207420
PR Review Comment: https://git.openjdk.org/jdk/pull/16465#discussion_r1386205635