Xcodel16 发生在 performIRGeneration 和 performLLVMOptimizations 阶段，这两个函数涉及 LLVM IR 生成 和 LLVM 优化

1. Apple Swift version 6.0 (swiftlang-6.0.0.9.10 clang-1600.0.26.2)
2. Compiling with effective version 5.10
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 0x00000001081230fc llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 56
1 swift-frontend 0x0000000108121350 llvm::sys::RunSignalHandlers() + 112
2 swift-frontend 0x00000001081236c8 SignalHandler(int) + 292
3 libsystem_platform.dylib 0x000000018652a584 _sigtramp + 56
4 libsystem_pthread.dylib 0x00000001864f9c20 pthread_kill + 288
5 libsystem_c.dylib 0x0000000186406a30 abort + 180
6 swift-frontend 0x0000000102e86bc8 createDispatchingDiagnosticConsumerIfNeeded(swift::FrontendInputsAndOutputs const&, llvm::function_ref> (swift::InputFile const&)>) + 0
7 swift-frontend 0x0000000108092e80 llvm::report_fatal_error(llvm::Twine const&, bool) + 280
8 swift-frontend 0x0000000108092d68 llvm::report_fatal_error(llvm::Twine const&, bool) + 0
9 swift-frontend 0x00000001030c731c llvm::detail::PassModel>::printPipeline(llvm::raw_ostream&, llvm::function_ref) + 0
10 swift-frontend 0x0000000107e5aa80 llvm::PassManager>::run(llvm::Module&, llvm::AnalysisManager&) + 224
11 swift-frontend 0x00000001030bbd58 swift::performLLVMOptimizations(swift::IRGenOptions const&, llvm::Module*, llvm::TargetMachine*, llvm::raw_pwrite_stream*) + 3764
12 swift-frontend 0x00000001030bd994 swift::performLLVM(swift::IRGenOptions const&, swift::DiagnosticEngine&, llvm::sys::SmartMutex*, llvm::GlobalVariable*, llvm::Module*, llvm::TargetMachine*, llvm::StringRef, llvm::vfs::OutputBackend&, swift::UnifiedStatsReporter*) + 2352
13 swift-frontend 0x00000001030c32ac swift::performIRGeneration(swift::ModuleDecl*, swift::IRGenOptions const&, swift::TBDGenOptions const&, std::__1::unique_ptr>, llvm::StringRef, swift::PrimarySpecificPaths const&, llvm::ArrayRef, std::__1::allocator>>, llvm::GlobalVariable**) + 5384
14 swift-frontend 0x0000000102ad28c4 generateIR(swift::IRGenOptions const&, swift::TBDGenOptions const&, std::__1::unique_ptr>, swift::PrimarySpecificPaths const&, llvm::StringRef, llvm::PointerUnion, llvm::GlobalVariable*&, llvm::ArrayRef, std::__1::allocator>>) + 260
15 swift-frontend 0x0000000102ace088 performCompileStepsPostSILGen(swift::CompilerInstance&, std::__1::unique_ptr>, llvm::PointerUnion, swift::PrimarySpecificPaths const&, int&, swift::FrontendObserver*) + 2176
16 swift-frontend 0x0000000102acd6e4 swift::performCompileStepsPostSema(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 2888
17 swift-frontend 0x0000000102ad0228 performCompile(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 1680
18 swift-frontend 0x0000000102acef58 swift::performFrontend(llvm::ArrayRef, char const*, void*, swift::FrontendObserver*) + 3572
19 swift-frontend 0x0000000102a5601c swift::mainEntry(int, char const**) + 3680
20 dyld 0x000000018616f154 start + 2476

Start by reproducing the crash with Apple Swift 6.0 while compiling with effective version 5.10, then inspect the reported performIRGeneration and performLLVMOptimizations stages. Use the stack trace as the initial boundary; the work is complete when the failure has a confirmed cause and an appropriate fix or diagnosis.

Written by the indexing model from the issue text.