1.85.0 Build fails with LLVM 20: PassWrapper.cpp: error: void value not ignored as it ought to be

[bbhtt]

  cargo:warning=llvm-wrapper/PassWrapper.cpp: In function 'bool LLVMRustPrepareThinLTORename(const LLVMRustThinLTOData*, LLVMModuleRef, LLVMTargetMachineRef)':
  cargo:warning=llvm-wrapper/PassWrapper.cpp:1399:38: error: void value not ignored as it ought to be
  cargo:warning= 1399 |   bool error = renameModuleForThinLTO(Mod, Data->Index, ClearDSOLocal);
  cargo:warning=      |                ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  --- stderr


  error occurred in cc-rs: Command LC_ALL="C" "/usr/bin/aarch64-unknown-linux-gnu-g++" "-O3" "-ffunction-sections" "-fdata-sections" "-fPIC" "-ffunction-sections" "-fdata-sections" "-fPIC" "-pipe" "-g" "-Wp,-D_FORTIFY_SOURCE=3" "-Wp,-D_GLIBCXX_ASSERTIONS" "-fexceptions" "-fstack-protector-strong" "-grecord-gcc-switches" "-fasynchronous-unwind-tables" "-fstack-clash-protection" "-fno-omit-frame-pointer" "-mno-omit-leaf-frame-pointer" "-mbranch-protection=standard" "-I/usr/include" "-std=c++17" "-fno-exceptions" "-funwind-tables" "-D_GNU_SOURCE" "-D__STDC_CONSTANT_MACROS" "-D__STDC_FORMAT_MACROS" "-D__STDC_LIMIT_MACROS" "-fno-omit-frame-pointer" "-DLLVM_COMPONENT_AARCH64" "-DLLVM_COMPONENT_AMDGPU" "-DLLVM_COMPONENT_ASMPARSER" "-DLLVM_COMPONENT_BITREADER" "-DLLVM_COMPONENT_BITWRITER" "-DLLVM_COMPONENT_BPF" "-DLLVM_COMPONENT_COVERAGE" "-DLLVM_COMPONENT_INSTRUMENTATION" "-DLLVM_COMPONENT_IPO" "-DLLVM_COMPONENT_LINKER" "-DLLVM_COMPONENT_LTO" "-DNDEBUG" "-o" "/buildstream-build/build/aarch64-unknown-linux-gnu/stage0-rustc/aarch64-unknown-linux-gnu/release/build/rustc_llvm-ec8cb299c4f7c658/out/ef10e86dc40538c1-PassWrapper.o" "-c" "llvm-wrapper/PassWrapper.cpp" with args aarch64-unknown-linux-gnu-g++ did not execute successfully (status code exit status: 1).


warning: build failed, waiting for other jobs to finish...
warning: `icu_locid_transform` (lib) generated 10 warnings

This is bootstrapped with 1.84.0 and LLVM is 20.1.0

Full log: build.txt

Please let me know if more information is needed.

[workingjubilee]

1.85 does not support LLVM 20. The commit that fixes that should be in 1.86