[AutoDiff] Fatal error of "do not know how to handle this incoming bb argument" when using a throwing function inside a differentiable function #70819
Description
Description
The use of a differentiable throwing function within an encapsulating differentiable function leads to a fatal error at compile time of do not know how to handle this incoming bb argument. This is similar to the case in #57523, but instead of the throwing function being used directly in gradient(at:of:) it is instead surrounded by a non-throwing differentiable function.
Reproduction
The following simple program reproduces this in a regular swiftc build:
import _Differentiation @differentiable(reverse) func test1(input: Float) throws -> Float { return input } @differentiable(reverse) func test2(input: Float) -> Float { do { return try test1(input: input) } catch { return 0.0 } } let (value, gradient) = valueWithGradient(at: 1.0, of: test2) print("Value: \(value), gradient: \(gradient)")The trace produced looks something like the following:
error: compile command failed due to signal 6 (use -v to see invocation) <unknown>:0: error: fatal error encountered during compilation; please submit a bug report (https://swift.org/contributing/#reporting-bugs) <unknown>:0: note: do not know how to handle this incoming bb argument Please submit a bug report (https://swift.org/contributing/#reporting-bugs) and include the crash backtrace. Stack dump: 0. Program arguments: /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2023-12-07-a.xctoolchain/usr/bin/swift-frontend -frontend -c -primary-file /Users/larson/Desktop/throwstest.swift -target arm64-apple-macosx13.0 -Xllvm -aarch64-use-tbi -enable-objc-interop -sdk /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.sdk -color-diagnostics -new-driver-path /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2023-12-07-a.xctoolchain/usr/bin/swift-driver -empty-abi-descriptor -resource-dir /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2023-12-07-a.xctoolchain/usr/lib/swift -module-name throwstest -target-sdk-version 14.2 -target-sdk-name macosx14.2 -external-plugin-path /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.sdk/usr/lib/swift/host/plugins#/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.sdk/usr/bin/swift-plugin-server -external-plugin-path /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.sdk/usr/local/lib/swift/host/plugins#/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.sdk/usr/bin/swift-plugin-server -external-plugin-path /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/lib/swift/host/plugins#/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/bin/swift-plugin-server -external-plugin-path /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/local/lib/swift/host/plugins#/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/bin/swift-plugin-server -plugin-path /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2023-12-07-a.xctoolchain/usr/lib/swift/host/plugins -plugin-path /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2023-12-07-a.xctoolchain/usr/local/lib/swift/host/plugins -o /var/folders/6y/ghmhq_xj3xq100vsttqqn2lc0000gq/T/TemporaryDirectory.jYso3S/throwstest-1.o 1. Apple Swift version 5.11-dev (LLVM 91cd37b9110872c, Swift 703a4719b0c6f3a) 2. Compiling with the current language version 3. While evaluating request ExecuteSILPipelineRequest(Run pipelines { Mandatory Diagnostic Passes + Enabling Optimization Passes } on SIL for throwstest) 4. While running pass #70 SILModuleTransform "Differentiation". 5. While processing // differentiability witness for test2(input:) sil_differentiability_witness hidden [reverse] [parameters 0] [results 0] @$s10throwstest5test25inputS2f_tF : $@convention(thin) (Float) -> Float { } on SIL function "@$s10throwstest5test25inputS2f_tF". for 'test2(input:)' (at /Users/larson/Desktop/throwstest.swift:9:1) 6. While generating VJP for SIL function "@$s10throwstest5test25inputS2f_tF". for 'test2(input:)' (at /Users/larson/Desktop/throwstest.swift:9:1) 7. While generating pullback for SIL function "@$s10throwstest5test25inputS2f_tF". for 'test2(input:)' (at /Users/larson/Desktop/throwstest.swift:9:1) Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it): 0 swift-frontend 0x00000001061db150 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 56 1 swift-frontend 0x00000001061d98ac llvm::sys::RunSignalHandlers() + 112 2 swift-frontend 0x00000001061db7a0 SignalHandler(int) + 304 3 libsystem_platform.dylib 0x000000019cd5ea24 _sigtramp + 56 4 libsystem_pthread.dylib 0x000000019cd2fc28 pthread_kill + 288 5 libsystem_c.dylib 0x000000019cc3dae8 abort + 180 6 swift-frontend 0x0000000100d8e848 PrettyStackTraceFrontend::~PrettyStackTraceFrontend() + 0 7 swift-frontend 0x0000000106154f84 llvm::report_fatal_error(llvm::Twine const&, bool) + 268 8 swift-frontend 0x0000000106154e78 llvm::report_fatal_error(llvm::Twine const&, bool) + 0 9 swift-frontend 0x000000010148e5dc swift::autodiff::PullbackCloner::Implementation::visitSILBasicBlock(swift::SILBasicBlock*) + 2680 10 swift-frontend 0x000000010148adcc swift::autodiff::PullbackCloner::Implementation::run() + 5276 11 swift-frontend 0x00000001014898f8 swift::autodiff::PullbackCloner::run() + 24 12 swift-frontend 0x00000001014a7670 swift::autodiff::VJPCloner::Implementation::run() + 1368 13 swift-frontend 0x00000001014a7da4 swift::autodiff::VJPCloner::run() + 24 14 swift-frontend 0x00000001015f05d4 (anonymous namespace)::DifferentiationTransformer::canonicalizeDifferentiabilityWitness(swift::SILDifferentiabilityWitness*, swift::autodiff::DifferentiationInvoker, swift::IsSerialized_t) + 6212 15 swift-frontend 0x00000001015ee460 (anonymous namespace)::Differentiation::run() + 1032 16 swift-frontend 0x00000001016a0a8c swift::SILPassManager::runModulePass(unsigned int) + 976 17 swift-frontend 0x00000001016a6b60 swift::SILPassManager::execute() + 624 18 swift-frontend 0x000000010169d950 swift::SILPassManager::executePassPipelinePlan(swift::SILPassPipelinePlan const&) + 68 19 swift-frontend 0x000000010169d8d8 swift::ExecuteSILPipelineRequest::evaluate(swift::Evaluator&, swift::SILPipelineExecutionDescriptor) const + 68 20 swift-frontend 0x00000001016e0794 swift::SimpleRequest<swift::ExecuteSILPipelineRequest, std::__1::tuple<> (swift::SILPipelineExecutionDescriptor), (swift::RequestFlags)1>::evaluateRequest(swift::ExecuteSILPipelineRequest const&, swift::Evaluator&) + 28 21 swift-frontend 0x00000001016c8510 llvm::Expected<swift::ExecuteSILPipelineRequest::OutputType> swift::Evaluator::getResultUncached<swift::ExecuteSILPipelineRequest>(swift::ExecuteSILPipelineRequest const&) + 268 22 swift-frontend 0x000000010169db40 swift::executePassPipelinePlan(swift::SILModule*, swift::SILPassPipelinePlan const&, bool, swift::irgen::IRGenModule*) + 84 23 swift-frontend 0x00000001016cb4f8 swift::runSILDiagnosticPasses(swift::SILModule&) + 192 24 swift-frontend 0x0000000100f77740 swift::CompilerInstance::performSILProcessing(swift::SILModule*) + 80 25 swift-frontend 0x0000000100d87b84 performCompileStepsPostSILGen(swift::CompilerInstance&, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule>>, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::PrimarySpecificPaths const&, int&, swift::FrontendObserver*) + 792 26 swift-frontend 0x0000000100d87284 swift::performCompileStepsPostSema(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 596 27 swift-frontend 0x0000000100d96ab8 withSemanticAnalysis(swift::CompilerInstance&, swift::FrontendObserver*, llvm::function_ref<bool (swift::CompilerInstance&)>, bool) + 160 28 swift-frontend 0x0000000100d89e78 performCompile(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 704 29 swift-frontend 0x0000000100d88e3c swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 2632 30 swift-frontend 0x0000000100c30c6c swift::mainEntry(int, char const**) + 2192 31 dyld 0x000000019c9d7f28 start + 2236 error: fatalError Expected behavior
The above should compile without error, and automatic differentiation should work correctly through the throwing function.
Environment
This is not a new regression, and is present in nightly toolchain snapshots and releases on various platforms dating back through at least the last year.
Additional information
No response