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REGRESSION(312651@main): 73 sec SwiftCompile CPU time, ~12 sec (1%) clean build time#64727

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rr-codes:eng/REGRESSION-312651-main-73-sec-SwiftCompile-CPU-time-12-sec-1-clean-build-time
May 12, 2026
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REGRESSION(312651@main): 73 sec SwiftCompile CPU time, ~12 sec (1%) clean build time#64727
webkit-commit-queue merged 1 commit into
WebKit:mainfrom
rr-codes:eng/REGRESSION-312651-main-73-sec-SwiftCompile-CPU-time-12-sec-1-clean-build-time

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@rr-codes rr-codes commented May 12, 2026

d97ee90

REGRESSION(312651@main): 73 sec SwiftCompile CPU time, ~12 sec (1%) clean build time
https://bugs.webkit.org/show_bug.cgi?id=314606
rdar://176604369

Reviewed by Geoffrey Garen and Elliott Williams.

312651@main set the Swift optimization level for WebKit to `-Onone` which matches the rest of the
project and aids in debugging. However, it caused negative build speed impact, so revert that part
of the change.

* Source/WebKit/Configurations/WebKit.xcconfig:

Canonical link: https://commits.webkit.org/313106@main

ac6ecd7

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@rr-codes rr-codes requested a review from emw-apple as a code owner May 12, 2026 04:09
@rr-codes rr-codes self-assigned this May 12, 2026
@rr-codes rr-codes added the WebKit Misc. For miscellaneous bugs in the WebKit framework (and not JavaScriptCore or WebCore). label May 12, 2026
@rr-codes rr-codes requested a review from geoffreygaren May 12, 2026 04:11
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Would be helpful to mention / link to the related back/forward list issue.

Comment on lines +77 to +79
// This should match the rest of WebKit and use `-Onone`, but it negatively impacts build time.
SWIFT_OPTIMIZATION_LEVEL[config=Debug] = -O;

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Are we sure this change alone addresses that back/forward list and build time issue?

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Yes, since it is the only functional change from my original commit.

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Given that we are in a situation of unexpected side-effects, I don't think we should assume too much about which parts of the commit are functional or not. I think we need to test (or just revert the full patch).

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the commit only moved things from one file to another, with the only non-moving part being this part, so I am confident this is the part to revert.

@rr-codes rr-codes added the merge-queue Applied to send a pull request to merge-queue label May 12, 2026
…lean build time

https://bugs.webkit.org/show_bug.cgi?id=314606
rdar://176604369

Reviewed by Geoffrey Garen and Elliott Williams.

312651@main set the Swift optimization level for WebKit to `-Onone` which matches the rest of the
project and aids in debugging. However, it caused negative build speed impact, so revert that part
of the change.

* Source/WebKit/Configurations/WebKit.xcconfig:

Canonical link: https://commits.webkit.org/313106@main
@webkit-commit-queue webkit-commit-queue force-pushed the eng/REGRESSION-312651-main-73-sec-SwiftCompile-CPU-time-12-sec-1-clean-build-time branch from ac6ecd7 to d97ee90 Compare May 12, 2026 20:56
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Committed 313106@main (d97ee90): https://commits.webkit.org/313106@main

Reviewed commits have been landed. Closing PR #64727 and removing active labels.

@webkit-commit-queue webkit-commit-queue merged commit d97ee90 into WebKit:main May 12, 2026
@webkit-commit-queue webkit-commit-queue removed the merge-queue Applied to send a pull request to merge-queue label May 12, 2026
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