[SR-9896] Performance degradation in String.UTF8View.elementsEqual() between Swift 4.2 and Swift 5 toolchains
#52302
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bug
A deviation from expected or documented behavior. Also: expected but undesirable behavior.
performance
standard library
Area: Standard library umbrella
Comments
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cc @milseman Do we have stdlib assertions turned on for development snapshot toolchains? |
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That would be a better question for @shahmishal |
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Regardless, I will look at this and also extend it a bit more. Some of the constant-costs in small string comparisons shifted around with the capability to store non-normalized content. I want to see if this is due to that and how salient it is in the context of other operations. |
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We don't have stdlib assertions enabled because --no-swift-stdlib-assertions is set. /Users/buildnode/jenkins/workspace/oss-swift-package-osx/swift/utils/build-script --ios --tvos --watchos --lldb --llbuild --swiftpm --swiftsyntax --skstresstester --swiftevolve --playgroundsupport --libcxx --indexstore-db --sourcekit-lsp --release-debuginfo --compiler-vendor=apple --lldb-no-debugserver --lldb-use-system-debugserver --lldb-build-type=Release --verbose-build --build-ninja --build-swift-static-stdlib --build-swift-static-sdk-overlay --build-swift-stdlib-unittest-extra --playgroundsupport-build-type=Release --install-swift --install-lldb --install-llbuild --install-swiftpm --install-swiftsyntax --skip-install-swiftsyntax-module --install-skstresstester --install-swiftevolve --install-playgroundsupport --install-destdir=/Users/buildnode/jenkins/workspace/oss-swift-package-osx/swift-nightly-install --darwin-install-extract-symbols --install-symroot=/Users/buildnode/jenkins/workspace/oss-swift-package-osx/swift-nightly-symroot --install-prefix=/Applications/Xcode.app/Contents/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2019-02-11-a.xctoolchain/usr --test-installable-package --reconfigure '--swift-install-components=compiler;clang-resource-dir-symlink;stdlib;sdk-overlay;parser-lib;license;sourcekit-xpc-service;swift-remote-mirror;swift-remote-mirror-headers' '--llvm-install-components=llvm-cov;llvm-profdata;IndexStore;clang;clang-headers;compiler-rt;clangd' --install-libcxx --installable-package=/Users/buildnode/jenkins/workspace/oss-swift-package-osx/swift-DEVELOPMENT-SNAPSHOT-2019-02-11-a-osx.tar.gz --symbols-package=/Users/buildnode/jenkins/workspace/oss-swift-package-osx/swift-DEVELOPMENT-SNAPSHOT-2019-02-11-a-osx-symbols.tar.gz --darwin-toolchain-bundle-identifier=org.swift.50201902111a '--darwin-toolchain-display-name=Swift Development Snapshot 2019-02-11 (a)' '--darwin-toolchain-display-name-short=Swift Development Snapshot' --darwin-toolchain-name=swift-DEVELOPMENT-SNAPSHOT-2019-02-11-a --darwin-toolchain-version=5.0.20190211101 --darwin-toolchain-alias=swift --build-subdir=buildbot_osx --ios --tvos --watchos --test --validation-test --long-test --stress-test --lldb-test-swift-only --installable-package=/Users/buildnode/jenkins/workspace/oss-swift-package-osx/swift-DEVELOPMENT-SNAPSHOT-2019-02-11-a-osx.tar.gz --assertions --no-swift-stdlib-assertions --swift-enable-ast-verifier=0 |
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Comment by Kyle Macomber (JIRA) @Azoy has made many optimizations to string equality recently. |
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Attachment: Download
Environment
Xcode 10.1
Swift 4.2 that ships with Xcode 10.1, and then Swift 5 Snapshot 2019-02-06
macOS 10.13.6
Additional Detail from JIRA
Watchers: @shahmishal
md5: baaaf243346ace1f7b5b36486fc42887
Issue Description:
The following is the test being run. See result in attached screenshot.
The text was updated successfully, but these errors were encountered: