8316893: Compile without -fno-delete-null-pointer-checks

[djelinski]

Please review this patch that reenables delete-null-pointer-checks optimization in GCC and Clang.

It also disables nonnull-compare warning that is now triggered in debug builds. The problematic code will be addressed by #15927.

Mach5 Tier1-5 testing clean.

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Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8316893: Compile without -fno-delete-null-pointer-checks (Enhancement - P4)

Reviewers

• Kim Barrett (@kimbarrett - Reviewer)
• Erik Joelsson (@erikj79 - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/15982/head:pull/15982
$ git checkout pull/15982

Update a local copy of the PR:
$ git checkout pull/15982
$ git pull https://git.openjdk.org/jdk.git pull/15982/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 15982

View PR using the GUI difftool:
$ git pr show -t 15982

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/15982.diff

Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back djelinski! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@djelinski The following label will be automatically applied to this pull request:

• build

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[TheShermanTanker]

Man, your work with clang is really leaving me in the dust :P
Have a thumbs up!

[mlbridge]

Webrevs

• 02: Full - Incremental (6e5738b6)
• 01: Full - Incremental (d4d79a81)
• 00: Full (b5aade6c)

[TheShermanTanker]

Might be safer to leave the quote around the DSE flag. Also, why not flag(s) instead?

[djelinski]

I reverted the quotes.
Didn't get your question; are you suggesting to rename the variable? I'd rather not do that, because 1) it increases the patch size, 2) all variables are global, so renaming might have unintended consequences, and 3) the old name is good enough.

[TheShermanTanker]

Ah no, I meant the comment, from This flag -> These flag(s), since it's implied that this site is where multiple gcc specific flags should be placed in the future. Just a small nit, nothing serious

[djelinski]

Ah. This place is for GCC6-related flags only, other flags are added in other places. I'm pretty sure we won't add any more flags for GCC6.

[openjdk]

@djelinski This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8316893: Compile without -fno-delete-null-pointer-checks

Reviewed-by: kbarrett, erikj

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 3 new commits pushed to the master branch:

• 878d27d: 8317273: compiler/codecache/OverflowCodeCacheTest.java fails transiently on Graal
• 2637e8d: 8317314: Remove unimplemented ObjArrayKlass::oop_oop_iterate_elements_bounded
• 8093563: 8317295: ResponseSubscribers.SubscriberAdapter should call the finisher function asynchronously

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[kimbarrett]

Looks good.

[djelinski]

/integrate

[openjdk]

Going to push as commit 287b243.
Since your change was applied there have been 12 commits pushed to the master branch:

• 26c21f5: 8314294: Unsafe::allocateMemory and Unsafe::freeMemory are slower than malloc/free
• 6e1aacd: 8296631: NSS tests failing on OL9 linux-aarch64 hosts
• d2e2c4c: 8309667: TLS handshake fails because of ConcurrentModificationException in PKCS12KeyStore.engineGetEntry
• e25121d: 8316929: Shenandoah: Shenandoah degenerated GC and full GC need to cleanup old OopMapCache entries
• 5c8366e: 8268622: Performance issues in javac Name class
• ad81abd: 8317034: Remove redundant type cast in the java.util.stream package
• d7d1d42: 8316771: Krb5.java has not defined messages for all error codes
• f985006: 8309356: Read files in includedir in alphanumeric order
• a564d43: 8315692: Parallelize gc/stress/TestStressRSetCoarsening.java test
• 878d27d: 8317273: compiler/codecache/OverflowCodeCacheTest.java fails transiently on Graal
• ... and 2 more: https://git.openjdk.org/jdk/compare/516cfb135f7e5fefaf6e6f2928f6ecb88806f1ef...master

Your commit was automatically rebased without conflicts.

[openjdk]

@djelinski Pushed as commit 287b243.

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