llvm error when building `compiler_builtins` with rustc with sancov since update to llvm 23

[matthiaskrgr]

I was trying to build rustc with coverage for afl once again but since the upgrade to llvm 23, llvm crashes in the process.

my repro looks somewhat like this

export RUSTC_BOOTSTRAP=1
echo "cargo afl config --update --force"
export AFLP=`cargo afl config --update --force |& grep home/matthias | awk 'NF>1{print $NF}'` #will not work for you like this but you get the idea
echo $AFLP # /home/matthias/.local/share/afl.rs/rustc-1.100.0-nightly-bff8e12/afl.rs-0.18.2
export AFL_LLVM_DENYLIST="/home/matthias/vcs/github/rust_fuzz/ignore_list.txt" #just just excludes ~/.cargo, can probably be skipped
export RUSTFLAGS=" -Clink-arg=${AFLP}/afl-llvm/afl-compiler-rt.o  -Ccodegen-units=1 -Copt-level=3 -Zvalidate-mir -Cpasses=sancov-module -Cllvm-args=-sanitizer-coverage-level=3 -Cllvm-args=-sanitizer-coverage-trace-pc-guard -Cllvm-args=-sanitizer-coverage-trace-compares --cfg=fuzzing -Ctarget-cpu=native -Clinker-plugin-lto -Zverify-llvm-ir  -Cllvm-args=--verify-machineinstrs   -Cllvm-args=--verify-memoryssa    -Cllvm-args=--verify-scev  -Cllvm-args=--verify-loop-info -Cllvm-args=--verify-memoryssa  -Cllvm-args=--verify-dom-info   -Cllvm-args=--verify-loop-lcssa  -Cllvm-args=--verify-regalloc -Cllvm-args=--verify-coalescing   -Cllvm-args=--verify-region-info  " # I threw in some llvm verifyer flags to see if they would catch anything
export AFL_MAP_SIZE=2996019

./x.py build --stage=1 compiler -j 5  # I "only" have 32 gb of ram so I needed to limit job count
export LD_BIND_LAZY="whatever"  #this fixed something for me but I dont remember what it was 

./x.py build library --target x86_64-unknown-linux-gnu  # this is the step that actually crashed

Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
    Finished `release` profile [optimized + debuginfo] target(s) in 0.43s
Creating a sysroot for stage1 compiler (use `rustup toolchain link 'name' build/host/stage1`)
Building stage1 lld-wrapper (stage0 -> stage1, x86_64-unknown-linux-gnu)
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
    Finished `release` profile [optimized + debuginfo] target(s) in 0.15s
Building stage1 library artifacts{alloc, compiler_builtins, core, panic_abort, panic_unwind, proc_macro, rustc-std-workspace-core, std, std_detect, sysroot, test, unwind} (stage1 -> stage1, x86_64-unknown-linux-gnu)
   Compiling compiler_builtins v0.1.160 (/home/matthias/vcs/github/rust_fuzz2/library/compiler-builtins/compiler-builtins)
   Compiling core v0.0.0 (/home/matthias/vcs/github/rust_fuzz2/library/core)
   Compiling libc v0.2.189
   Compiling object v0.39.1
   Compiling std v0.0.0 (/home/matthias/vcs/github/rust_fuzz2/library/std)
   Compiling test v0.0.0 (/home/matthias/vcs/github/rust_fuzz2/library/test)
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 5399589 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2996024 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 5399589 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2996024 to be able to run this instrumented program if this crashes!
   Compiling rustc-std-workspace-core v1.99.0 (/home/matthias/vcs/github/rust_fuzz2/library/rustc-std-workspace-core)
   Compiling alloc v0.0.0 (/home/matthias/vcs/github/rust_fuzz2/library/alloc)
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 5399589 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 5399589 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2996024 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2996024 to be able to run this instrumented program if this crashes!
   Compiling adler2 v2.0.1
   Compiling memchr v2.8.3
   Compiling cfg-if v1.0.4
   Compiling panic_abort v0.0.0 (/home/matthias/vcs/github/rust_fuzz2/library/panic_abort)
   Compiling rustc-demangle v0.1.28
   Compiling rustc-literal-escaper v0.0.8
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2998000 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 5399589 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2996024 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 5399589 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 5399589 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 5399589 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2996024 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2996024 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 5399589 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2996024 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2996024 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 5399589 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2996024 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 5399589 to be able to run this instrumented program if this crashes!
Warning: AFL++ tools might need to set AFL_MAP_SIZE to 2996024 to be able to run this instrumented program if this crashes!
error: rustc interrupted by SIGSEGV, printing backtrace

/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/librustc_driver-9ab9d1c29af0b044.so(+0x1d02a25) [0x7f1efc102a25]
/usr/lib/libc.so.6(+0x3e6f0) [0x7f1efa03e6f0]
/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/libLLVM.so.23.1-rust-1.99.0-nightly(_ZNK4llvm18ModuleSummaryIndex21getGlobalValueSummaryEmb+0x2e) [0x7f1ef53fa3ee]
/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/libLLVM.so.23.1-rust-1.99.0-nightly(+0xa375bcf) [0x7f1ef9375bcf]
/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/libLLVM.so.23.1-rust-1.99.0-nightly(_ZN4llvm26ModuleSummaryIndexAnalysis3runERNS_6ModuleERNS_15AnalysisManagerIS1_JEEE+0xc4) [0x7f1ef850689e]
/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/libLLVM.so.23.1-rust-1.99.0-nightly(+0x9504d6a) [0x7f1ef8504d6a]
/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/libLLVM.so.23.1-rust-1.99.0-nightly(_ZN4llvm15AnalysisManagerINS_6ModuleEJEE13getResultImplEPNS_11AnalysisKeyERS1_+0x1cb) [0x7f1ef8506f4b]
/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/libLLVM.so.23.1-rust-1.99.0-nightly(_ZN4llvm24ThinLTOBitcodeWriterPass3runERNS_6ModuleERNS_15AnalysisManagerIS1_JEEE+0x5d) [0x7f1ef85057e7]
/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/libLLVM.so.23.1-rust-1.99.0-nightly(_ZN4llvm11PassManagerINS_6ModuleENS_15AnalysisManagerIS1_JEEEJEE3runERS1_RS3_+0x1c9) [0x7f1ef85077e5]
/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/librustc_driver-9ab9d1c29af0b044.so(+0x1abc646) [0x7f1efbebc646]
/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/librustc_driver-9ab9d1c29af0b044.so(+0x236bf42) [0x7f1efc76bf42]
/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/librustc_driver-9ab9d1c29af0b044.so(_RNvXs1_Cskf4YuM4rH4g_18rustc_codegen_llvmNtB5_18LlvmCodegenBackendNtNtNtCs9550KEFd23i_17rustc_codegen_ssa6traits5write19WriteBackendMethods8optimize+0x4c7) [0x7f1efc7fd9b7]
/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/librustc_driver-9ab9d1c29af0b044.so(_RINvNtNtCs30yU1cfpkQp_3std3sys9backtrace28___rust_begin_short_backtraceNCINvNtNtCs9550KEFd23i_17rustc_codegen_ssa4back5write10spawn_workNtCskf4YuM4rH4g_18rustc_codegen_llvm18LlvmCodegenBackendE0uEB2c_+0x207) [0x7f1efc5cf777]
/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/librustc_driver-9ab9d1c29af0b044.so(+0x2287af6) [0x7f1efc687af6]
/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1/lib/librustc_driver-9ab9d1c29af0b044.so(+0x1b2a14f) [0x7f1efbf2a14f]
/usr/lib/libc.so.6(+0x980a2) [0x7f1efa0980a2]
/usr/lib/libc.so.6(+0x12080c) [0x7f1efa12080c]

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
rustc exited with signal: 11 (SIGSEGV)
error: could not compile `compiler_builtins` (lib)

Caused by:
  process didn't exit successfully: `/home/matthias/vcs/github/rust_fuzz2/build/bootstrap/debug/rustc /home/matthias/vcs/github/rust_fuzz2/build/bootstrap/debug/rustc --crate-name compiler_builtins --edition=2024 library/compiler-builtins/compiler-builtins/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=157 --crate-type lib --emit=dep-info,metadata,link -Z embed-metadata=no -C opt-level=3 -C embed-bitcode=no -C codegen-units=10000 -C debuginfo=2 -Cembed-bitcode=yes -Zunstable-options -Cforce-frame-pointers=non-leaf -C debug-assertions=on --cfg 'feature="arch"' --cfg 'feature="compiler-builtins"' --cfg 'feature="default"' --cfg 'feature="unmangled-names"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("arch", "c", "compiler-builtins", "default", "mem", "unmangled-names", "unstable-public-internals"))' -C metadata=b0ff770c38593253 -C extra-filename=-432d535274f3888d --out-dir /home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1-std/x86_64-unknown-linux-gnu/dist/build/compiler_builtins/432d535274f3888d/out --target x86_64-unknown-linux-gnu -L dependency=/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1-std/x86_64-unknown-linux-gnu/dist/build/core/ad7eacf41182b861/out -L dependency=/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1-std/dist/build/compiler_builtins/432d535274f3888d/out --extern core=/home/matthias/vcs/github/rust_fuzz2/build/x86_64-unknown-linux-gnu/stage1-std/x86_64-unknown-linux-gnu/dist/build/core/ad7eacf41182b861/out/libcore-ad7eacf41182b861.rmeta -Zannotate-moves '--check-cfg=cfg(feature,values(any()))' -Zunstable-options -Zmacro-backtrace -Csplit-debuginfo=off -Cprefer-dynamic -Zinline-mir -Zinline-mir-preserve-debug -Zmir_strip_debuginfo=locals-in-tiny-functions -Clink-args=-Wl,-z,origin '-Clink-args=-Wl,-rpath,$ORIGIN/../lib' -Alinker-messages '-Zcrate-attr=doc(html_root_url="https://doc.rust-lang.org/nightly/")' -Clink-arg=/home/matthias/.local/share/afl.rs/rustc-1.100.0-nightly-bff8e12/afl.rs-0.18.2/afl-llvm/afl-compiler-rt.o -Ccodegen-units=1 -Copt-level=3 -Zvalidate-mir -Cpasses=sancov-module -Cllvm-args=-sanitizer-coverage-level=3 -Cllvm-args=-sanitizer-coverage-trace-pc-guard -Cllvm-args=-sanitizer-coverage-trace-compares --cfg=fuzzing -Ctarget-cpu=native -Clinker-plugin-lto -Zverify-llvm-ir -Cllvm-args=--verify-machineinstrs -Cllvm-args=--verify-memoryssa -Cllvm-args=--verify-scev -Cllvm-args=--verify-loop-info -Cllvm-args=--verify-memoryssa -Cllvm-args=--verify-dom-info -Cllvm-args=--verify-loop-lcssa -Cllvm-args=--verify-regalloc -Cllvm-args=--verify-coalescing -Cllvm-args=--verify-region-info -Z binary-dep-depinfo --cfg intrinsics_enabled --cfg optimizations_enabled --cfg f16_enabled --cfg f128_enabled --cfg mem_unaligned --check-cfg 'cfg(thumb)' --check-cfg 'cfg(thumb_1)' --check-cfg 'cfg(x86_no_sse2)' --check-cfg 'cfg(assert_no_panic)' --check-cfg 'cfg(intrinsics_enabled)' --check-cfg 'cfg(optimizations_enabled)' --check-cfg 'cfg(f16_enabled)' --check-cfg 'cfg(f128_enabled)' --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(mem_unaligned)' --check-cfg 'cfg(kernel_user_helpers)'` (exit status: 254)
warning: build failed, waiting for other jobs to finish...
Build completed unsuccessfully in 0:01:54

[im-lunex]

im not sure but this one looks like LLVMs fault.. cuz recently i mean 1-2days ago while working on a PR i saw that there was some issues going on the llvm's main stream.. that's why several test's failed --- it might be related to that issue..

[matthiaskrgr]

with debug-assertions stage0, we end up here

rustc: /checkout/src/llvm-project/llvm/lib/IR/Globals.cpp:106: GlobalValue::GUID llvm::GlobalValue::getGUID() const: Assertion `MaybeGUID.has_value() && "GUID was not assigned before calling GetGUID()"' failed.
rustc exited with signal: 6 (SIGABRT)
error: could not compile `compiler_builtins` (lib)

https://github.com/rust-lang/llvm-project/blob/rustc/23.1-2026-07-22/llvm/lib/IR/Globals.cpp#L106

[matthiaskrgr]

I was wondering if this was maybe some kind of mismatch between my local clang 22.1.8 and rustc being on llvm 23 already, but so far I have not been able to reproduce this kind of error when compiling other random crates outside of the rustc repo 🤔

@nikic do you have an idea what could be going on here?

[matthiaskrgr]

From playing around with minimization a for a couple of hours, I suspect that the culprint is somewhere within a combination of libm (which lives inside compiler_builtins) + instrumented core / alloc

maybe its possible to get a compiler-builtins standalone repro using -Zbuild-std

[matthiaskrgr]

sooo it seems that in library/Cargo.toml , we override codegen-units for compiler-builtins and set debug=0 opt-level=s for some of its dependencies.
When I remove all of that, the build seems to pass 😵
not sure if this is worth investigating further

[Gelbpunkt]

I'm seeing what I believe to be the same issues when attempting to build Rust with LLVM 23 in Alpine Linux. We're compiling 1.98.1 (with LLVM 23) with a stage0 compiler that is 1.97.0 (with LLVM 22). The stage1 build succeeds, the stage2 build then fails. If I raise the stack size with export RUST_MIN_STACK=16777216, it crashes with Assertion failed: MaybeGUID.has_value() && "GUID was not assigned before calling GetGUID()" (/builds/Aelin/aports/main/llvm23/src/llvm-project-23.1.1.src/llvm/lib/IR/Globals.cpp: getGUID: 105) (had to build LLVM 23 with assertions, otherwise the error is very cryptic in libstdc++ headers).

EDIT: This does not happen on x86_64, but apparently on virtually every other architecture.

[nikic]

1.98 does not support LLVM 23. Did you backport all the necessary patches? In particular, do you have #158961?

[Gelbpunkt]

Ah, I thought 1.98 supported LLVM 23. I do not have #158961 at the moment, I only cherry-picked the patches to remove AMX-TF32.