I've observed a significant performance regression in Apple Clang 16 (Xcode 16.0/16.2) compared to Clang 15 (Xcode 15.2) when processing flutter aot compilation. Further research shows that clang -cc1as process became extremely slow. The compilation time has increased by approximately 4x. Environment Machine: Apple M2 (8C8T) Memory: 16GB macOS Version: 14.7.2 Target: Flutter AOT compilation (snapshot_assembly.o) Performance Comparison Xcode Version iOS SDK Duration 15.2 17.2 1:08.90 15.2 18.2 1:03.98 16.2 17.2 4:11.07 16.2 18.2 4:08.43 16.0 18.2 4:29.32 Reproduction Steps The issue can be reproduced with the following command which is generated by flutter aot_assembly_release process: time ${xcode_app_path}/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cc \ -arch arm64 \ -miphoneos-version-min=12.0 \ -v \ -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS18.2.sdk \ -c ${project_path}/.dart_tool/flutter_build/f9ebf46f040933de7c8d103c84d38156/arm64/snapshot_assembly.S \ -o ${project_path}/.dart_tool/flutter_build/f9ebf46f040933de7c8d103c84d38156/arm64/snapshot_assembly.o Additional Information This issue specifically affects large assembly files generated by Flutter's AOT compilation The performance regression appears to be consistent across different iOS SDK versions The same assembly file compiles significantly faster with Xcode 15.2 Same performance regression observed on M4 Mac mini, suggesting this is not hardware-specific Size of object: size -m ${project_path}/.dart_tool/flutter_build/f9ebf46f040933de7c8d103c84d38156/arm64/snapshot_assembly.o Segment : 64577616 Section (__TEXT, __text): 26603344 Section (__DATA, __bss): 48 (zerofill) Section (__TEXT, __const): 21292928 Section (__DWARF, __debug_abbrev): 61 Section (__DWARF, __debug_info): 8934534 Section (__DWARF, __debug_line): 4464443 Section (__LD, __compact_unwind): 3282208 total 64577566 total 64577616 Questions Is this a known issue with Apple Clang 16? Are there any workarounds or compiler flags we can use to improve the performance? Is this behavior expected or should it be considered a regression? Any insights or suggestions would be greatly appreciated.