Optimize Specializations of Variadic Generics by Eliminating Parameter Packs #84513

aidan-hall · 2025-09-25T10:16:32Z

rdar://161182876

There are two key barriers that prevent variadic generic specialisations from being optimised in most cases:

Indirect packs in the calling convention: These force the caller to make a large number of stack allocations, since the pack is passed indirectly, and pack elements are currently always pointers, so every element must be stack-allocated separately from the pack.
Pack loops and open_pack_element: These perform one iteration per pack element, so the loop body must be generic, with witness_method instructions that cannot be eliminated, since the type they are called on is not known.

Targeted modifications to eliminate these barriers will allow other passes to fully optimise variadic generic specialisations.

This PR only addresses the first barrier, indirect packs as function arguments.

The simplest way to eliminate indirect packs from the calling convention is effectively to move the stack allocations for the packs and pack elements inside the callee, and use the addresses of these local allocations in the main body, which is otherwise unchanged. These allocations can be eliminated by other passes once dynamic pack loops are optimised.

This transformation is performed by a function pass (currently called pack-specialization). For example, it would transform the following specialisation like so:

sil shared @$s11addTogether8doubleUp2xsxxQp_xxQptxxQp_tRvzlFSi_SdSSSJQP_Tg5 : $@convention(thin) (@pack_guaranteed Pack{Int, Double, String, Character}) -> (@pack_out Pack{Int, Double, String, Character}, @pack_out Pack{Int, Double, String, Character}) {
bb0(%0 : $*Pack{Int, Double, String, Character}, %1 : $*Pack{Int, Double, String, Character}, %2 : $*Pack{Int, Double, String, Character}):
  debug_value %2, let, name "xs", argno 1, expr op_deref
  …

sil shared @$s11addTogether8doubleUp2xsxxQp_xxQptxxQp_tRvzlFSi_SdSSSJQP_Tg5Tf8xxx_n : $@convention(thin) (Int, Double, @guaranteed String, @guaranteed Character) -> (Int, Double, @owned String, @owned Character, Int, Double, @owned String, @owned Character) {
bb0(%0 : $Int, %1 : $Double, %2 : $String, %3 : $Character):
  %4 = alloc_pack $Pack{Int, Double, String, Character}
  %5 = scalar_pack_index 0 of $Pack{Int, Double, String, Character}
  %6 = alloc_stack $Int
  store %0 to %6
  …
  debug_value %4, let, name "xs", argno 1, expr op_deref
  …

Note that the return values are all now direct, so bb0 only needs arguments corresponding to the xs parameter pack.

To optimise a pack loop, it must be unrolled. The pack element type is then statically known in each unrolled instance of the body. The existing loop unrolling pass can consistently do this in variadic generic specialisations, since the (known constant) pack length is used as the number of iterations. This still leaves constructs like the following:

  %5 = integer_literal $Builtin.Word, 0
  %6 = dynamic_pack_index %5 of $Pack{Int, Double}
  %7 = open_pack_element %6 of <each A where repeat each A : Numeric> at <Pack{Int, Double}>, shape $each A, uuid "063BDCF4-98A3-11F0-B2E8-929C59BC796C"
  %20 = witness_method $@pack_element("063BDCF4-98A3-11F0-B2E8-929C59BC796C") each A, #Numeric."*" …
  %21 = apply %20<@pack_element("063BDCF4-98A3-11F0-B2E8-929C59BC796C") each A>(%10, %14, %18, %11) … // type-defs: %7

In this context, we could easily replace all instances of the @pack_element type with Int. This would allow the appropriate witness method to be inlined. We will perform this in an instruction simplification for open_pack_element.

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/PackSpecialization.swift

SwiftCompilerSources/Sources/Optimizer/PassManager/FunctionPassContext.swift

SwiftCompilerSources/Sources/SIL/Argument.swift

SwiftCompilerSources/Sources/SIL/BasicBlock.swift

SwiftCompilerSources/Sources/SIL/Function.swift

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/PackSpecialization.swift

aidan-hall · 2025-10-03T16:27:40Z

@swift-ci smoke test macOS

aidan-hall · 2025-10-06T11:45:09Z

@swift-ci smoke test macOS

SwiftCompilerSources/Sources/Optimizer/PassManager/FunctionPassContext.swift

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/PackSpecialization.swift

eeckstein · 2025-10-07T08:11:15Z

SwiftCompilerSources/Sources/SIL/Type.swift


+  public var packExpansionPatternType: Type { bridged.getPackExpansionPatternType().type }
+
+  public var hasParameterPack: Bool {


I think it makes sense to move (most of) these APIs to TypeProperties so that they are also available for AST.Type and AST.CanonicalType. The SILType implementation forwards them to the AST type, anyway

eeckstein

looks great!

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/PackSpecialization.swift

aidan-hall · 2025-10-17T10:31:56Z

@swift-ci test

aidan-hall · 2025-10-17T11:16:03Z

@swift-ci smoke test linux

aidan-hall · 2025-10-17T11:16:18Z

@swift-ci smoke test macos

aidan-hall · 2025-10-17T11:40:59Z

@swift-ci smoke test

aidan-hall · 2025-10-20T11:09:42Z

@swift-ci smoke test macos

aidan-hall · 2025-10-20T11:16:10Z

@swift-ci smoke test macos

aidan-hall · 2025-10-20T11:16:22Z

@swift-ci smoke test linux

aidan-hall · 2025-10-20T11:16:31Z

@swift-ci test windows

aidan-hall · 2025-10-21T09:49:48Z

@swift-ci test macos

aidan-hall · 2025-10-21T09:52:33Z

@swift-ci test windows

aidan-hall · 2025-10-21T13:29:22Z

@swift-ci smoke test

aidan-hall · 2025-10-23T09:29:15Z

@swift-ci smoke test macos

aidan-hall · 2025-10-23T15:17:28Z

@swift-ci Please Test Source Compatibility Release

aidan-hall · 2025-10-23T15:17:51Z

@swift-ci test macos

aidan-hall · 2025-10-24T09:13:47Z

@swift-ci test macos

aidan-hall · 2025-10-26T08:42:42Z

@swift-ci Please Test Source Compatibility Release

aidan-hall · 2025-10-26T14:17:57Z

@swift-ci test

aidan-hall · 2025-10-26T14:18:21Z

@swift-ci smoke test

aidan-hall · 2025-10-26T14:18:37Z

@swift-ci Please Test Source Compatibility Release

aidan-hall · 2025-10-30T14:32:04Z

All tests passed previously except 1 source compatibility test (which does not use packs), due to an unrelated bug.
Force-pushed to invalidate the previous results, now running minimum smoke tests to merge.
@swift-ci smoke test linux
@swift-ci smoke test windows
@swift-ci test windows
@swift-ci smoke benchmark

aidan-hall · 2025-10-30T14:32:53Z

@swift-ci smoke test linux

aidan-hall · 2025-10-30T14:33:00Z

@swift-ci smoke test macos

aidan-hall · 2025-10-30T14:33:05Z

@swift-ci test windows

finagolfin · 2025-11-01T10:49:46Z

Hello Aidan, this new test you added is failing for the new 32-bit Android armv7 compiler validation suite run that was added, and will probably fail on the 32-bit watchOS CI also:

[2025-11-01T06:57:34.217Z] FAIL: Swift(android-armv7) :: SILOptimizer/pack_specialization.swift (8889 of 20537)
[2025-11-01T06:57:34.217Z] ******************** TEST 'Swift(android-armv7) :: SILOptimizer/pack_specialization.swift' FAILED ********************
[2025-11-01T06:57:34.217Z] Exit Code: 1
[2025-11-01T06:57:34.217Z] 
[2025-11-01T06:57:34.217Z] Command Output (stderr):
[2025-11-01T06:57:34.217Z] --
[2025-11-01T06:57:34.217Z] /home/build-user/build/swift-project/Ninja-Release/swift-linux-x86_64/bin/swift-frontend -target armv7-unknown-linux-android -sdk /home/build-user/build/ndk/android-ndk-r27d/toolchains/llvm/prebuilt/linux-x86_64/sysroot -resource-dir /home/build-user/build/swift-project/Ninja-Release/swift-linux-x86_64/lib/swift -module-cache-path /home/build-user/build/swift-project/Ninja-Release/swift-linux-x86_64/swift-test-results/armv7-unknown-linux-androideabi/clang-module-cache -swift-version 4  -define-availability 'SwiftStdlib 9999:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999' -define-availability 'StdlibDeploymentTarget 9999:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999' -define-availability 'SwiftStdlib 5.0:macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2' -define-availability 'StdlibDeploymentTarget 5.0:macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2' -define-availability 'SwiftStdlib 5.1:macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0' -define-availability 'StdlibDeploymentTarget 5.1:macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0' -define-availability 'SwiftStdlib 5.2:macOS 10.15.4, iOS 13.4, watchOS 6.2, tvOS 13.4' -define-availability 'StdlibDeploymentTarget 5.2:macOS 10.15.4, iOS 13.4, watchOS 6.2, tvOS 13.4' -define-availability 'SwiftStdlib 5.3:macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0' -define-availability 'StdlibDeploymentTarget 5.3:macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0' -define-availability 'SwiftStdlib 5.4:macOS 11.3, iOS 14.5, watchOS 7.4, tvOS 14.5' -define-availability 'StdlibDeploymentTarget 5.4:macOS 11.3, iOS 14.5, watchOS 7.4, tvOS 14.5' -define-availability 'SwiftStdlib 5.5:macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0' -define-availability 'StdlibDeploymentTarget 5.5:macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0' -define-availability 'SwiftStdlib 5.6:macOS 12.3, iOS 15.4, watchOS 8.5, tvOS 15.4' -define-availability 'StdlibDeploymentTarget 5.6:macOS 12.3, iOS 15.4, watchOS 8.5, tvOS 15.4' -define-availability 'SwiftStdlib 5.7:macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0' -define-availability 'StdlibDeploymentTarget 5.7:macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0' -define-availability 'SwiftStdlib 5.8:macOS 13.3, iOS 16.4, watchOS 9.4, tvOS 16.4' -define-availability 'StdlibDeploymentTarget 5.8:macOS 13.3, iOS 16.4, watchOS 9.4, tvOS 16.4' -define-availability 'SwiftStdlib 5.9:macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0' -define-availability 'StdlibDeploymentTarget 5.9:macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0' -define-availability 'SwiftStdlib 5.10:macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4, visionOS 1.1' -define-availability 'StdlibDeploymentTarget 5.10:macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4, visionOS 1.1' -define-availability 'SwiftStdlib 6.0:macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0' -define-availability 'StdlibDeploymentTarget 6.0:macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0' -define-availability 'SwiftStdlib 6.1:macOS 15.4, iOS 18.4, watchOS 11.4, tvOS 18.4, visionOS 2.4' -define-availability 'StdlibDeploymentTarget 6.1:macOS 15.4, iOS 18.4, watchOS 11.4, tvOS 18.4, visionOS 2.4' -define-availability 'SwiftStdlib 6.2:macOS 26.0, iOS 26.0, watchOS 26.0, tvOS 26.0, visionOS 26.0' -define-availability 'StdlibDeploymentTarget 6.2:macOS 26.0, iOS 26.0, watchOS 26.0, tvOS 26.0, visionOS 26.0' -define-availability 'SwiftStdlib 6.3:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999' -define-availability 'StdlibDeploymentTarget 6.3:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999' -define-availability 'SwiftCompatibilitySpan 5.0:macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2, visionOS 1.0' -define-availability 'SwiftCompatibilitySpan 6.2:macOS 26.0, iOS 26.0, watchOS 26.0, tvOS 26.0, visionOS 26.0' -typo-correction-limit 10  /source/swift-project/swift/test/SILOptimizer/pack_specialization.swift -emit-ir -O | /usr/bin/python3.12 /source/swift-project/swift/utils/PathSanitizingFileCheck --allow-unused-prefixes --sanitize TMP_DIR=/home/build-user/build/swift-project/Ninja-Release/swift-linux-x86_64/test-android-armv7/SILOptimizer/Output/pack_specialization.swift.tmp --sanitize BUILD_DIR=/home/build-user/build/swift-project/Ninja-Release/swift-linux-x86_64 --sanitize SOURCE_DIR=/source/swift-project/swift --ignore-runtime-warnings --use-filecheck /home/build-user/build/swift-project/Ninja-Release/llvm-linux-x86_64/bin/FileCheck   /source/swift-project/swift/test/SILOptimizer/pack_specialization.swift # RUN: at line 1
[2025-11-01T06:57:34.217Z] + /usr/bin/python3.12 /source/swift-project/swift/utils/PathSanitizingFileCheck --allow-unused-prefixes --sanitize TMP_DIR=/home/build-user/build/swift-project/Ninja-Release/swift-linux-x86_64/test-android-armv7/SILOptimizer/Output/pack_specialization.swift.tmp --sanitize BUILD_DIR=/home/build-user/build/swift-project/Ninja-Release/swift-linux-x86_64 --sanitize SOURCE_DIR=/source/swift-project/swift --ignore-runtime-warnings --use-filecheck /home/build-user/build/swift-project/Ninja-Release/llvm-linux-x86_64/bin/FileCheck /source/swift-project/swift/test/SILOptimizer/pack_specialization.swift
[2025-11-01T06:57:34.217Z] + /home/build-user/build/swift-project/Ninja-Release/swift-linux-x86_64/bin/swift-frontend -target armv7-unknown-linux-android -sdk /home/build-user/build/ndk/android-ndk-r27d/toolchains/llvm/prebuilt/linux-x86_64/sysroot -resource-dir /home/build-user/build/swift-project/Ninja-Release/swift-linux-x86_64/lib/swift -module-cache-path /home/build-user/build/swift-project/Ninja-Release/swift-linux-x86_64/swift-test-results/armv7-unknown-linux-androideabi/clang-module-cache -swift-version 4 -define-availability 'SwiftStdlib 9999:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999' -define-availability 'StdlibDeploymentTarget 9999:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999' -define-availability 'SwiftStdlib 5.0:macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2' -define-availability 'StdlibDeploymentTarget 5.0:macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2' -define-availability 'SwiftStdlib 5.1:macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0' -define-availability 'StdlibDeploymentTarget 5.1:macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0' -define-availability 'SwiftStdlib 5.2:macOS 10.15.4, iOS 13.4, watchOS 6.2, tvOS 13.4' -define-availability 'StdlibDeploymentTarget 5.2:macOS 10.15.4, iOS 13.4, watchOS 6.2, tvOS 13.4' -define-availability 'SwiftStdlib 5.3:macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0' -define-availability 'StdlibDeploymentTarget 5.3:macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0' -define-availability 'SwiftStdlib 5.4:macOS 11.3, iOS 14.5, watchOS 7.4, tvOS 14.5' -define-availability 'StdlibDeploymentTarget 5.4:macOS 11.3, iOS 14.5, watchOS 7.4, tvOS 14.5' -define-availability 'SwiftStdlib 5.5:macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0' -define-availability 'StdlibDeploymentTarget 5.5:macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0' -define-availability 'SwiftStdlib 5.6:macOS 12.3, iOS 15.4, watchOS 8.5, tvOS 15.4' -define-availability 'StdlibDeploymentTarget 5.6:macOS 12.3, iOS 15.4, watchOS 8.5, tvOS 15.4' -define-availability 'SwiftStdlib 5.7:macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0' -define-availability 'StdlibDeploymentTarget 5.7:macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0' -define-availability 'SwiftStdlib 5.8:macOS 13.3, iOS 16.4, watchOS 9.4, tvOS 16.4' -define-availability 'StdlibDeploymentTarget 5.8:macOS 13.3, iOS 16.4, watchOS 9.4, tvOS 16.4' -define-availability 'SwiftStdlib 5.9:macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0' -define-availability 'StdlibDeploymentTarget 5.9:macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0' -define-availability 'SwiftStdlib 5.10:macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4, visionOS 1.1' -define-availability 'StdlibDeploymentTarget 5.10:macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4, visionOS 1.1' -define-availability 'SwiftStdlib 6.0:macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0' -define-availability 'StdlibDeploymentTarget 6.0:macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0' -define-availability 'SwiftStdlib 6.1:macOS 15.4, iOS 18.4, watchOS 11.4, tvOS 18.4, visionOS 2.4' -define-availability 'StdlibDeploymentTarget 6.1:macOS 15.4, iOS 18.4, watchOS 11.4, tvOS 18.4, visionOS 2.4' -define-availability 'SwiftStdlib 6.2:macOS 26.0, iOS 26.0, watchOS 26.0, tvOS 26.0, visionOS 26.0' -define-availability 'StdlibDeploymentTarget 6.2:macOS 26.0, iOS 26.0, watchOS 26.0, tvOS 26.0, visionOS 26.0' -define-availability 'SwiftStdlib 6.3:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999' -define-availability 'StdlibDeploymentTarget 6.3:macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999' -define-availability 'SwiftCompatibilitySpan 5.0:macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2, visionOS 1.0' -define-availability 'SwiftCompatibilitySpan 6.2:macOS 26.0, iOS 26.0, watchOS 26.0, tvOS 26.0, visionOS 26.0' -typo-correction-limit 10 /source/swift-project/swift/test/SILOptimizer/pack_specialization.swift -emit-ir -O
[2025-11-01T06:57:34.217Z] /source/swift-project/swift/test/SILOptimizer/pack_specialization.swift:6:11: error: CHECK: expected string not found in input
[2025-11-01T06:57:34.217Z] // CHECK: define {{.*}} { i64, i64, ptr, double } @"$s19pack_specialization8copyPack2xsxxQp_txxQp_tRvzlFSi_SSSdQP_Tg5Tf8xx_n"(i64 %0, i64 %1, ptr %2, double %3)
[2025-11-01T06:57:34.217Z]           ^
[2025-11-01T06:57:34.217Z] <stdin>:1:1: note: scanning from here
[2025-11-01T06:57:34.217Z] ; ModuleID = '<swift-imported-modules>'
[2025-11-01T06:57:34.217Z] ^
[2025-11-01T06:57:34.217Z] 
[2025-11-01T06:57:34.217Z] Input file: <stdin>
[2025-11-01T06:57:34.217Z] Check file: /source/swift-project/swift/test/SILOptimizer/pack_specialization.swift
[2025-11-01T06:57:34.217Z] 
[2025-11-01T06:57:34.217Z] -dump-input=help explains the following input dump.
[2025-11-01T06:57:34.217Z] 
[2025-11-01T06:57:34.217Z] Input was:
[2025-11-01T06:57:34.217Z] <<<<<<
[2025-11-01T06:57:34.217Z]          1: ; ModuleID = '<swift-imported-modules>' 
[2025-11-01T06:57:34.217Z] check:6     X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
[2025-11-01T06:57:34.217Z]          2: source_filename = "<swift-imported-modules>" 
[2025-11-01T06:57:34.217Z] check:6     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[2025-11-01T06:57:34.217Z]          3: target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64" 
[2025-11-01T06:57:34.217Z] check:6     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[2025-11-01T06:57:34.217Z]          4: target triple = "armv7-unknown-linux-android" 
[2025-11-01T06:57:34.217Z] check:6     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[2025-11-01T06:57:34.217Z]          5:  
[2025-11-01T06:57:34.217Z] check:6     ~
[2025-11-01T06:57:34.217Z]          6: %swift.type = type { i32 } 
[2025-11-01T06:57:34.217Z] check:6     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
[2025-11-01T06:57:34.217Z]          .
[2025-11-01T06:57:34.217Z]          .
[2025-11-01T06:57:34.217Z]          .
[2025-11-01T06:57:34.217Z] >>>>>>
[2025-11-01T06:57:34.217Z] 
[2025-11-01T06:57:34.217Z] --
[2025-11-01T06:57:34.217Z] 
[2025-11-01T06:57:34.217Z] ********************

Can you take a look?

aidan-hall · 2025-11-03T09:41:26Z

Will do. Looks like I can probably just replace with Int with Int32 in the test source.

aidan-hall · 2025-11-03T10:37:57Z

@finagolfin #85279

aidan-hall self-assigned this Sep 25, 2025

aidan-hall added the parameter packs Feature → generics: Parameter packs label Sep 25, 2025

eeckstein reviewed Sep 25, 2025

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eeckstein reviewed Sep 26, 2025

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aidan-hall force-pushed the pack-opt branch from bf95a88 to a84ca01 Compare September 26, 2025 14:22

aidan-hall force-pushed the pack-opt branch from fbe06ad to 3cbf374 Compare October 3, 2025 15:34

aidan-hall marked this pull request as ready for review October 3, 2025 16:26

aidan-hall requested review from hborla, jckarter, rjmccall, slavapestov and xedin as code owners October 3, 2025 16:26

eeckstein reviewed Oct 7, 2025

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aidan-hall marked this pull request as draft October 14, 2025 14:18

eeckstein previously approved these changes Oct 16, 2025

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aidan-hall closed this Oct 17, 2025

aidan-hall deleted the pack-opt branch October 17, 2025 09:40

aidan-hall restored the pack-opt branch October 17, 2025 09:40

aidan-hall reopened this Oct 17, 2025

aidan-hall force-pushed the pack-opt branch 2 times, most recently from 9e37826 to 6b9f9ec Compare October 17, 2025 10:30

aidan-hall marked this pull request as ready for review October 17, 2025 10:31

aidan-hall requested a review from eeckstein October 17, 2025 10:34

aidan-hall force-pushed the pack-opt branch from 6b9f9ec to 452e8a3 Compare October 17, 2025 11:40

aidan-hall force-pushed the pack-opt branch from 315eb4e to 272dca2 Compare October 20, 2025 11:15

aidan-hall force-pushed the pack-opt branch from 272dca2 to e58b1eb Compare October 21, 2025 13:28

Bridging: APIs for PackSpecialization pass

c7af4c5

aidan-hall force-pushed the pack-opt branch from e58b1eb to 3ba867d Compare October 26, 2025 14:17

Create Pack Specialisation pass

8632e58

aidan-hall force-pushed the pack-opt branch from 3ba867d to 8632e58 Compare October 30, 2025 14:28

aidan-hall merged commit a8cef44 into swiftlang:main Oct 31, 2025
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aidan-hall deleted the pack-opt branch November 11, 2025 11:41


		public var packExpansionPatternType: Type { bridged.getPackExpansionPatternType().type }

		public var hasParameterPack: Bool {

Optimize Specializations of Variadic Generics by Eliminating Parameter Packs #84513

Optimize Specializations of Variadic Generics by Eliminating Parameter Packs #84513

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aidan-hall commented Oct 20, 2025

Uh oh!

aidan-hall commented Oct 20, 2025

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aidan-hall commented Oct 20, 2025

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aidan-hall commented Oct 21, 2025

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aidan-hall commented Oct 21, 2025

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aidan-hall commented Oct 21, 2025

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aidan-hall commented Oct 23, 2025

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aidan-hall commented Oct 23, 2025

Uh oh!

aidan-hall commented Oct 23, 2025

Uh oh!

aidan-hall commented Oct 24, 2025

Uh oh!

aidan-hall commented Oct 26, 2025

Uh oh!

aidan-hall commented Oct 26, 2025

Uh oh!

aidan-hall commented Oct 26, 2025

Uh oh!

aidan-hall commented Oct 26, 2025

Uh oh!

aidan-hall commented Oct 30, 2025

Uh oh!

aidan-hall commented Oct 30, 2025

aidan-hall commented Sep 25, 2025 •

edited

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finagolfin commented Nov 1, 2025 •

edited

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