Fix missing goto block when adding edges back to the unrolled header

[a7ehuo]

When newTo is different from newFromNextBlock in fall into case, goto block needs to be added besides
of the cfg edges because the newTo block is not the fall through block.

Fixes: eclipse-openj9/openj9#15764

Signed-off-by: Annabelle Huo Annabelle.Huo@ibm.com

[a7ehuo]

@hzongaro @vijaysun-omr May I ask you to review this change? Thank you!

I'm keeping WIP until the Jenkins test completes. Currently the Jenkins personal build test is broken.

[vijaysun-omr]

I feel a more descriptive explanation of the problem and how it is being fixed at a high level may be useful.

[a7ehuo]

@vijaysun-omr I added more details to the original issue eclipse-openj9/openj9#15764 (comment) using the block that shows the issue as an example with trace logs.

[a7ehuo]

@vijaysun-omr @hzongaro Just following up and see if there are more review comments before I do another push to address the above comment

[hzongaro]

Annabelle @a7ehuo, I don't have any additional review comments.

[0xdaryl]

@a7ehuo : are there any more pushes coming?

@hzongaro @vijaysun-omr : once Annabelle confirms or pushes final commit can you formally approve your comments?

[a7ehuo]

are there any more pushes coming?

Yes, I have one more commit to address the above comment. I wasn't sure if @vijaysun-omr would have any further comment. If not, I'll push another commit shortly

[a7ehuo]

@vijaysun-omr @hzongaro Just pushed another commit ddc6a80 to address the comment. Ready for another review. Thanks!

[hzongaro]

I think the changes look good

[a7ehuo]

I found more information on why eclipse-openj9/openj9#15764 happens so far only on the modified class file. I need more time to assess if this fix is the ideal fix for this bug. Change to WIP status

[a7ehuo]

@vijaysun-omr I added a clarification in the original issue after some offline discussion with @jdmpapin. In short, the issue hits the case where multiple cloned blocks need to jump to the loop entry which is a fall through of the original block. This case is unexpected by addEdgeAndFixEverything and not common in our existing test suites. This change addresses this issue. I've removed WIP from this PR. It's ready for review again. Thanks!

[vijaysun-omr]

Thanks for that clarification, it addresses my question of why this is so rare. The rare part is that we have the fall through into loop header and we are cloning the predecessor that is falling through.

[vijaysun-omr]

Jenkins build all

[a7ehuo]

zos_390-64 failed with the following error. It looks like an infrastructure issue

10:46:40   > /u/user1/jenkins-zos/git fetch --tags --progress git@github.com:eclipse/omr.git +refs/pull/6693/merge:refs/remotes/origin/pr/6693/merge # timeout=30
10:42:58  ERROR: Error cloning remote repo 'origin'
10:42:58  hudson.plugins.git.GitException: Command "/u/user1/jenkins-zos/git fetch --tags --progress git@github.com:eclipse/omr.git +refs/pull/6693/merge:refs/remotes/origin/pr/6693/merge" returned status code 128:
10:42:58  stdout: FOTS1370 Host key verification failed.
10:42:58  fatal: Could not read from remote repository.
10:42:58  
10:42:58  Please make sure you have the correct access rights
10:42:58  and the repository exists.
10:42:58  
10:42:58  stderr: 
10:42:58  	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandIn(CliGitAPIImpl.java:2675)
...
ERROR: Error cloning remote repo 'origin'
Setting status of ddc6a80d57c9c3217909b3a7d862bf191586a595 to FAILURE with url https://ci.eclipse.org/omr/job/PullRequest-zos_390-64/3864/ and message: 'Build finished. '
Using context: continuous-integration/eclipse-omr/pr/zos_390-64
Finished: FAILURE

[a7ehuo]

jenkins build zos

[a7ehuo]

@AdamBrousseau The zos has been failing consistently with stdout: FOTS1370 Host key verification failed error.: 3864 and 3866 Could you help take a look?

[a7ehuo]

The same failure was reported preivously in #6672 (comment) as well

[AdamBrousseau]

jenkins build zos