SIGSEGV when crosscompiling m68k on Apple silicon

I periodically try to use the m68k backend to follow the progress of this endeavour. Mostly I've run into #89498, but this time I encountered a new and exciting failure: a backtrace!

ketsuban@Mac rustygendev % cargo +nightly build --verbose -Zunstable-options -Zbuild-std=core --target m68k-unknown-none-elf
   Compiling compiler_builtins v0.1.152
   Compiling core v0.0.0 (/Users/ketsuban/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/core)
     Running `/Users/ketsuban/.rustup/toolchains/nightly-aarch64-apple-darwin/bin/rustc --crate-name core --edition=2024 /Users/ketsuban/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=192 --crate-type lib --emit=dep-info,metadata,link -C panic=abort -C embed-bitcode=no -C debuginfo=2 --warn=unexpected_cfgs --check-cfg 'cfg(bootstrap)' --check-cfg 'cfg(no_fp_fmt_parse)' --check-cfg 'cfg(stdarch_intel_sde)' --check-cfg 'cfg(target_feature, values("vector-enhancements-1"))' --check-cfg 'cfg(feature, values(any()))' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("debug_refcell", "debug_typeid", "optimize_for_size", "panic_immediate_abort"))' -C metadata=824c1c1b04613d66 -C extra-filename=-e42f79a39d447cc3 --out-dir /Users/ketsuban/Documents/Projects/rustygendev/target/m68k-unknown-none-elf/debug/deps --target m68k-unknown-none-elf -Z force-unstable-if-unmarked -L dependency=/Users/ketsuban/Documents/Projects/rustygendev/target/m68k-unknown-none-elf/debug/deps -L dependency=/Users/ketsuban/Documents/Projects/rustygendev/target/debug/deps --cap-lints allow`
     Running `/Users/ketsuban/.rustup/toolchains/nightly-aarch64-apple-darwin/bin/rustc --crate-name build_script_build --edition=2021 /Users/ketsuban/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/compiler_builtins-0.1.152/build.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=192 --crate-type bin --emit=dep-info,link -C embed-bitcode=no -C debuginfo=2 -C split-debuginfo=unpacked --cfg 'feature="compiler-builtins"' --cfg 'feature="core"' --cfg 'feature="default"' --cfg 'feature="rustc-dep-of-std"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("c", "cc", "compiler-builtins", "core", "default", "mangled-names", "mem", "no-asm", "no-f16-f128", "public-test-deps", "rustc-dep-of-std"))' -C metadata=4d6eb78ac32657a6 -C extra-filename=-7dd1e0c714ddc77d --out-dir /Users/ketsuban/Documents/Projects/rustygendev/target/debug/build/compiler_builtins-7dd1e0c714ddc77d -Z force-unstable-if-unmarked -L dependency=/Users/ketsuban/Documents/Projects/rustygendev/target/debug/deps --cap-lints allow`
     Running `/Users/ketsuban/Documents/Projects/rustygendev/target/debug/build/compiler_builtins-7dd1e0c714ddc77d/build-script-build`
   Compiling rustc-std-workspace-core v1.99.0 (/Users/ketsuban/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/rustc-std-workspace-core)
     Running `/Users/ketsuban/.rustup/toolchains/nightly-aarch64-apple-darwin/bin/rustc --crate-name rustc_std_workspace_core --edition=2024 /Users/ketsuban/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/rustc-std-workspace-core/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=192 --crate-type lib --emit=dep-info,metadata,link -C panic=abort -C embed-bitcode=no -C debuginfo=2 --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values())' -C metadata=47fe63df76ed21ec -C extra-filename=-c5710ba5a9ef0130 --out-dir /Users/ketsuban/Documents/Projects/rustygendev/target/m68k-unknown-none-elf/debug/deps --target m68k-unknown-none-elf -Z force-unstable-if-unmarked -L dependency=/Users/ketsuban/Documents/Projects/rustygendev/target/m68k-unknown-none-elf/debug/deps -L dependency=/Users/ketsuban/Documents/Projects/rustygendev/target/debug/deps --extern core=/Users/ketsuban/Documents/Projects/rustygendev/target/m68k-unknown-none-elf/debug/deps/libcore-e42f79a39d447cc3.rmeta --cap-lints allow`
     Running `/Users/ketsuban/.rustup/toolchains/nightly-aarch64-apple-darwin/bin/rustc --crate-name compiler_builtins --edition=2021 /Users/ketsuban/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/compiler_builtins-0.1.152/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=192 --crate-type lib --emit=dep-info,metadata,link -C panic=abort -C embed-bitcode=no -C debuginfo=2 --cfg 'feature="compiler-builtins"' --cfg 'feature="core"' --cfg 'feature="default"' --cfg 'feature="rustc-dep-of-std"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("c", "cc", "compiler-builtins", "core", "default", "mangled-names", "mem", "no-asm", "no-f16-f128", "public-test-deps", "rustc-dep-of-std"))' -C metadata=709e534c2b3ab102 -C extra-filename=-fa5a7129e0d8d4cb --out-dir /Users/ketsuban/Documents/Projects/rustygendev/target/m68k-unknown-none-elf/debug/deps --target m68k-unknown-none-elf -Z force-unstable-if-unmarked -L dependency=/Users/ketsuban/Documents/Projects/rustygendev/target/m68k-unknown-none-elf/debug/deps -L dependency=/Users/ketsuban/Documents/Projects/rustygendev/target/debug/deps --extern core=/Users/ketsuban/Documents/Projects/rustygendev/target/m68k-unknown-none-elf/debug/deps/librustc_std_workspace_core-c5710ba5a9ef0130.rmeta --cap-lints allow --cfg f16_enabled --cfg f128_enabled --cfg intrinsics_enabled --cfg arch_enabled --cfg 'feature="unstable-intrinsics"' --cfg 'feature="mem"' --check-cfg 'cfg(__ashldi3, values("optimized-c"))' --check-cfg 'cfg(__ashlsi3, values("optimized-c"))' --check-cfg 'cfg(__ashrdi3, values("optimized-c"))' --check-cfg 'cfg(__ashrsi3, values("optimized-c"))' --check-cfg 'cfg(__bswapsi2, values("optimized-c"))' --check-cfg 'cfg(__bswapdi2, values("optimized-c"))' --check-cfg 'cfg(__bswapti2, values("optimized-c"))' --check-cfg 'cfg(__divdi3, values("optimized-c"))' --check-cfg 'cfg(__divsi3, values("optimized-c"))' --check-cfg 'cfg(__divmoddi4, values("optimized-c"))' --check-cfg 'cfg(__divmodsi4, values("optimized-c"))' --check-cfg 'cfg(__divmodsi4, values("optimized-c"))' --check-cfg 'cfg(__divmodti4, values("optimized-c"))' --check-cfg 'cfg(__lshrdi3, values("optimized-c"))' --check-cfg 'cfg(__lshrsi3, values("optimized-c"))' --check-cfg 'cfg(__moddi3, values("optimized-c"))' --check-cfg 'cfg(__modsi3, values("optimized-c"))' --check-cfg 'cfg(__muldi3, values("optimized-c"))' --check-cfg 'cfg(__udivdi3, values("optimized-c"))' --check-cfg 'cfg(__udivmoddi4, values("optimized-c"))' --check-cfg 'cfg(__udivmodsi4, values("optimized-c"))' --check-cfg 'cfg(__udivsi3, values("optimized-c"))' --check-cfg 'cfg(__umoddi3, values("optimized-c"))' --check-cfg 'cfg(__umodsi3, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(target_feature, values("vis3"))' --check-cfg 'cfg(feature, values("checked"))' --check-cfg 'cfg(assert_no_panic)' --check-cfg 'cfg(f16_enabled)' --check-cfg 'cfg(f128_enabled)' --check-cfg 'cfg(thumb)' --check-cfg 'cfg(thumb_1)' --check-cfg 'cfg(intrinsics_enabled)' --check-cfg 'cfg(arch_enabled)' --check-cfg 'cfg(optimizations_enabled)' --check-cfg 'cfg(feature, values("unstable-public-internals"))' --check-cfg 'cfg(optimizations_enabled)' --check-cfg 'cfg(x86_no_sse)' --check-cfg 'cfg(feature, values("mem-unaligned"))' --check-cfg 'cfg(kernel_user_helpers)'`
error: rustc interrupted by SIGSEGV, printing backtrace

0   librustc_driver-5eb14ee39bea4f61.dy 0x000000010e1b7288 _RNvNtCs7jfflK3Ezi4_17rustc_driver_impl14signal_handler17print_stack_trace + 140
1   libsystem_platform.dylib            0x000000019b27b624 _sigtramp + 56
2   librustc_driver-5eb14ee39bea4f61.dy 0x0000000111a592ec _ZN12_GLOBAL__N_117ScheduleDAGRRList20ListScheduleBottomUpEv + 892
3   librustc_driver-5eb14ee39bea4f61.dy 0x0000000111a58f44 _ZN12_GLOBAL__N_117ScheduleDAGRRList8ScheduleEv + 432
4   librustc_driver-5eb14ee39bea4f61.dy 0x0000000111afbabc _ZN4llvm16SelectionDAGISel17CodeGenAndEmitDAGEv + 1004
5   librustc_driver-5eb14ee39bea4f61.dy 0x0000000111afb21c _ZN4llvm16SelectionDAGISel20SelectAllBasicBlocksERKNS_8FunctionE + 5208
6   librustc_driver-5eb14ee39bea4f61.dy 0x0000000111af9358 _ZN4llvm16SelectionDAGISel20runOnMachineFunctionERNS_15MachineFunctionE + 348
7   librustc_driver-5eb14ee39bea4f61.dy 0x0000000111af7ccc _ZN4llvm22SelectionDAGISelLegacy20runOnMachineFunctionERNS_15MachineFunctionE + 196
8   librustc_driver-5eb14ee39bea4f61.dy 0x0000000111d86408 _ZN4llvm19MachineFunctionPass13runOnFunctionERNS_8FunctionE + 576
9   librustc_driver-5eb14ee39bea4f61.dy 0x0000000112a0f64c _ZN4llvm13FPPassManager13runOnFunctionERNS_8FunctionE + 668
10  librustc_driver-5eb14ee39bea4f61.dy 0x0000000112a15e38 _ZN4llvm13FPPassManager11runOnModuleERNS_6ModuleE + 60
11  librustc_driver-5eb14ee39bea4f61.dy 0x0000000112a10124 _ZN4llvm6legacy15PassManagerImpl3runERNS_6ModuleE + 2172
12  librustc_driver-5eb14ee39bea4f61.dy 0x0000000112c176b8 LLVMRustWriteOutputFile + 528
13  librustc_driver-5eb14ee39bea4f61.dy 0x000000010de60974 _RNvNtNtCsa56ATgAlpKf_18rustc_codegen_llvm4back5write17write_output_file + 268
14  librustc_driver-5eb14ee39bea4f61.dy 0x000000010de6505c _RNvNtNtCsa56ATgAlpKf_18rustc_codegen_llvm4back5write7codegen + 3956
15  librustc_driver-5eb14ee39bea4f61.dy 0x000000010dde5ba4 _RINvNtNtCs1CCrylYwiyQ_17rustc_codegen_ssa4back5write24finish_intra_module_workNtCsa56ATgAlpKf_18rustc_codegen_llvm18LlvmCodegenBackendEB1g_ + 136
16  librustc_driver-5eb14ee39bea4f61.dy 0x000000010dde6d70 _RINvNtNtCsb6ViYdwWw0s_3std3sys9backtrace28___rust_begin_short_backtraceNCINvXs0_Csa56ATgAlpKf_18rustc_codegen_llvmNtB1g_18LlvmCodegenBackendNtNtNtCs1CCrylYwiyQ_17rustc_codegen_ssa6traits7backend19ExtraBackendMethods18spawn_named_threadNCINvNtNtB2k_4back5write10spawn_workB1O_E0uE0uEB1g_ + 2320
17  librustc_driver-5eb14ee39bea4f61.dy 0x000000010de06934 _RNSNvYNCINvMNtCsb6ViYdwWw0s_3std6threadNtBa_7Builder16spawn_unchecked_NCINvXs0_Csa56ATgAlpKf_18rustc_codegen_llvmNtB1f_18LlvmCodegenBackendNtNtNtCs1CCrylYwiyQ_17rustc_codegen_ssa6traits7backend19ExtraBackendMethods18spawn_named_threadNCINvNtNtB2j_4back5write10spawn_workB1N_E0uE0uEs_0INtNtNtCs7vhvaqLtEKV_4core3ops8function6FnOnceuE9call_once6vtableB1f_ + 472
18  librustc_driver-5eb14ee39bea4f61.dy 0x000000010ffd5d38 _ZN3std3sys3pal4unix6thread6Thread3new12thread_start17h25cf63c7bb5b77dfE + 52
19  libsystem_pthread.dylib             0x000000019b241c0c _pthread_start + 136
20  libsystem_pthread.dylib             0x000000019b23cb80 thread_start + 8

note: we would appreciate a report at https://github.com/rust-lang/rust
help: you can increase rustc's stack size by setting RUST_MIN_STACK=16777216
note: backtrace dumped due to SIGSEGV! resuming signal
error: could not compile `compiler_builtins` (lib)

Caused by:
  process didn't exit successfully: `/Users/ketsuban/.rustup/toolchains/nightly-aarch64-apple-darwin/bin/rustc --crate-name compiler_builtins --edition=2021 /Users/ketsuban/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/compiler_builtins-0.1.152/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=192 --crate-type lib --emit=dep-info,metadata,link -C panic=abort -C embed-bitcode=no -C debuginfo=2 --cfg 'feature="compiler-builtins"' --cfg 'feature="core"' --cfg 'feature="default"' --cfg 'feature="rustc-dep-of-std"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("c", "cc", "compiler-builtins", "core", "default", "mangled-names", "mem", "no-asm", "no-f16-f128", "public-test-deps", "rustc-dep-of-std"))' -C metadata=709e534c2b3ab102 -C extra-filename=-fa5a7129e0d8d4cb --out-dir /Users/ketsuban/Documents/Projects/rustygendev/target/m68k-unknown-none-elf/debug/deps --target m68k-unknown-none-elf -Z force-unstable-if-unmarked -L dependency=/Users/ketsuban/Documents/Projects/rustygendev/target/m68k-unknown-none-elf/debug/deps -L dependency=/Users/ketsuban/Documents/Projects/rustygendev/target/debug/deps --extern core=/Users/ketsuban/Documents/Projects/rustygendev/target/m68k-unknown-none-elf/debug/deps/librustc_std_workspace_core-c5710ba5a9ef0130.rmeta --cap-lints allow --cfg f16_enabled --cfg f128_enabled --cfg intrinsics_enabled --cfg arch_enabled --cfg 'feature="unstable-intrinsics"' --cfg 'feature="mem"' --check-cfg 'cfg(__ashldi3, values("optimized-c"))' --check-cfg 'cfg(__ashlsi3, values("optimized-c"))' --check-cfg 'cfg(__ashrdi3, values("optimized-c"))' --check-cfg 'cfg(__ashrsi3, values("optimized-c"))' --check-cfg 'cfg(__bswapsi2, values("optimized-c"))' --check-cfg 'cfg(__bswapdi2, values("optimized-c"))' --check-cfg 'cfg(__bswapti2, values("optimized-c"))' --check-cfg 'cfg(__divdi3, values("optimized-c"))' --check-cfg 'cfg(__divsi3, values("optimized-c"))' --check-cfg 'cfg(__divmoddi4, values("optimized-c"))' --check-cfg 'cfg(__divmodsi4, values("optimized-c"))' --check-cfg 'cfg(__divmodsi4, values("optimized-c"))' --check-cfg 'cfg(__divmodti4, values("optimized-c"))' --check-cfg 'cfg(__lshrdi3, values("optimized-c"))' --check-cfg 'cfg(__lshrsi3, values("optimized-c"))' --check-cfg 'cfg(__moddi3, values("optimized-c"))' --check-cfg 'cfg(__modsi3, values("optimized-c"))' --check-cfg 'cfg(__muldi3, values("optimized-c"))' --check-cfg 'cfg(__udivdi3, values("optimized-c"))' --check-cfg 'cfg(__udivmoddi4, values("optimized-c"))' --check-cfg 'cfg(__udivmodsi4, values("optimized-c"))' --check-cfg 'cfg(__udivsi3, values("optimized-c"))' --check-cfg 'cfg(__umoddi3, values("optimized-c"))' --check-cfg 'cfg(__umodsi3, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(target_feature, values("vis3"))' --check-cfg 'cfg(feature, values("checked"))' --check-cfg 'cfg(assert_no_panic)' --check-cfg 'cfg(f16_enabled)' --check-cfg 'cfg(f128_enabled)' --check-cfg 'cfg(thumb)' --check-cfg 'cfg(thumb_1)' --check-cfg 'cfg(intrinsics_enabled)' --check-cfg 'cfg(arch_enabled)' --check-cfg 'cfg(optimizations_enabled)' --check-cfg 'cfg(feature, values("unstable-public-internals"))' --check-cfg 'cfg(optimizations_enabled)' --check-cfg 'cfg(x86_no_sse)' --check-cfg 'cfg(feature, values("mem-unaligned"))' --check-cfg 'cfg(kernel_user_helpers)'` (signal: 11, SIGSEGV: invalid memory reference)
ketsuban@Mac rustygendev % rustc +nightly --version --verbose
rustc 1.88.0-nightly (d5b4c2e4f 2025-04-02)
binary: rustc
commit-hash: d5b4c2e4f19b6d7037371cdaecc3cc2c701c68df
commit-date: 2025-04-02
host: aarch64-apple-darwin
release: 1.88.0-nightly
LLVM version: 20.1.1

I merely dabble in the magical arts; I leave understanding this to a higher-level wizard than myself.

Reproduce the failure with the reported cargo +nightly build command for the m68k-unknown-none-elf target on Apple silicon. Start by examining the SIGSEGV backtrace and the rustc invocation around compiler_builtins; done means this cross-compilation build no longer crashes.