8292338: aarch64: Use cbnz instruction in gen_continuation_enter when possible

[RealFYang]

This is a trivial improvement for gen_continuation_enter on AArch64. On AAch64, we can combine Compare and Branch on Zero/Nonzero into CBZ/CBNZ to save one instruction. Tier1 tested with fastdebug build on aarch64-linux-gnu.

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Progress

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

Issue

• JDK-8292338: aarch64: Use cbnz instruction in gen_continuation_enter when possible

Reviewers

• Hao Sun (@shqking - Author)
• Aleksey Shipilev (@shipilev - Reviewer)
• Andrew Haley (@theRealAph - Reviewer)

Reviewing

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$ git fetch https://git.openjdk.org/jdk pull/9872/head:pull/9872
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Update a local copy of the PR:
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$ git pr checkout 9872

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https://git.openjdk.org/jdk/pull/9872.diff

[bridgekeeper[bot]]

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[openjdk[bot]]

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

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[mlbridge[bot]]

Webrevs

• 00: Full (13229486)

[openjdk[bot]]

@RealFYang 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:

8292338: aarch64: Use cbnz instruction in gen_continuation_enter when possible

Reviewed-by: haosun, shade, aph

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 4 new commits pushed to the master branch:

• ec96b1f1879ee8ee5164be22d0a178f9d5048ab9: 8290291: G1: Merge multiple calls of block_size in HeapRegion::block_start
• fd4b2f2868ac6eaf192b50db5c5adc76e0d54308: 8291718: Remove mark_for_deoptimization from klass unloading
• 9d7c13eb14c525485e7739fcfacd044aa3bbc12d: 8155246: Throw error if default java.security file is missing
• e89abb7d2d902c6e6b3c9953fc6663de10db77b9: 8292190: [IR Framework] Remove redundant regex matching for failing counts constraints

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.

[RealFYang]

Thanks all for the quick review. /integrate

[openjdk[bot]]

Going to push as commit d1edda8ff52e172a85d102d7d5062b9cc401beea. Since your change was applied there have been 13 commits pushed to the master branch:

• 21f4eb2233a95be44a5db59b7791cd952ddbd56e: 6521141: DebugGraphics NPE @ setFont();
• 6e6ae596d6bd73909b90911e01fbd0c16f6335e1: 8292286: Convert PlaceholderTable to ResourceHashtable
• ea2c82e74f5580f396920f9e561cbec80c03f373: 8291949: Unexpected extending of SupportedGroups
• b5707b0376660cd8763e46d525ba614b08a59d7b: 8292196: Reduce runtime of java.util.regex microbenchmarks
• b00eedeb029445417f99e8aa4e8fca12e5c69155: 8291511: Redefinition of EXIT_FAILURE in libw2k_lsa_auth
• 3a090777bada2e00f573fe8ab113bfa3884982eb: 8291337: Reduce runtime of vm.lamdba microbenchmarks
• dd2034b00725f0fc777c1706b1db898475e89c5c: 8291972: Fix double copy of arguments when thawing two interpreted frames
• aa5b71893307b9fe6137bc3541edccaab73735ac: 8292182: [TESTLIB] Enhance JAXPPolicyManager to setup required permissions for jtreg version 7 jar
• 695bb3939135394a4627d1c41cfc30d11b19bf48: 8292347: Remove unused Type::is_ptr_to_boxing_obj
• ec96b1f1879ee8ee5164be22d0a178f9d5048ab9: 8290291: G1: Merge multiple calls of block_size in HeapRegion::block_start
• ... and 3 more: https://git.openjdk.org/jdk/compare/77cd917a97b184871ab2d3325ceb6c53afeca28b...master

Your commit was automatically rebased without conflicts.

[openjdk[bot]]

@RealFYang Pushed as commit d1edda8ff52e172a85d102d7d5062b9cc401beea.

:bulb: You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.