[llvm] [LLVM][MC][DecoderEmitter] Add support to specialize decoder per bitwidth (PR #154865)

Tue Sep 2 03:38:30 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `flang-runtime-cuda-gcc` running on `as-builder-7` while building `llvm` at step 6 "build-flang-rt".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/152/builds/4830

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (build-flang-rt) failure: cmake (failure)
...
39.065 [604/20/6457] Building CXX object lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/RISCVISelDAGToDAG.cpp.o
39.066 [604/19/6458] Building CXX object lib/Target/RISCV/MCTargetDesc/CMakeFiles/LLVMRISCVDesc.dir/RISCVMCTargetDesc.cpp.o
39.085 [604/18/6459] Linking CXX static library lib/libLLVMRISCVInfo.a
39.185 [603/18/6460] Linking CXX static library lib/libLLVMRISCVDesc.a
39.191 [602/18/6461] Building CXX object lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/GISel/RISCVInstructionSelector.cpp.o
39.226 [601/18/6462] Linking CXX static library lib/libLLVMRISCVAsmParser.a
39.422 [601/17/6463] Linking CXX static library lib/libLLVMRISCVCodeGen.a
39.447 [601/16/6464] Building AMDGPUGenRegisterInfo.inc...
39.568 [601/15/6465] Linking CXX executable bin/lli
45.896 [601/14/6466] Building CXX object lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o
FAILED: lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o 
ccache /usr/bin/g++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GLIBCXX_USE_CXX11_ABI=1 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/build/lib/Target/RISCV/Disassembler -I/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/llvm/lib/Target/RISCV/Disassembler -I/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/llvm/lib/Target/RISCV -I/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/build/lib/Target/RISCV -I/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/build/include -I/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17 -fvisibility=hidden  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -MD -MT lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o -MF lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o.d -o lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o -c /home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp
/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp:705:13: error: explicit template specialization cannot have a storage class
  705 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint16_t> = 16;
      |             ^~~~~~
/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp:706:13: error: explicit template specialization cannot have a storage class
  706 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint32_t> = 32;
      |             ^~~~~~
/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp:708:13: error: explicit template specialization cannot have a storage class
  708 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint64_t> = 48;
      |             ^~~~~~
46.962 [601/13/6467] Building AMDGPUGenRegisterBank.inc...
51.737 [601/12/6468] Building CXX object tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/common.cpp.o
52.085 [601/11/6469] Building CXX object tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/complex.cpp.o
52.536 [601/10/6470] Building CXX object tools/flang/lib/Semantics/CMakeFiles/FortranSemantics.dir/cmake_pch.hxx.gch
61.933 [601/9/6471] Building CXX object tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/constant.cpp.o
73.328 [601/8/6472] Building CXX object tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/call.cpp.o
83.948 [601/7/6473] Building CXX object tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/expression.cpp.o
84.585 [601/6/6474] Building CXX object tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/fold-designator.cpp.o
93.422 [601/5/6475] Building CXX object tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/characteristics.cpp.o
95.510 [601/4/6476] Building CXX object tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/fold.cpp.o
99.237 [601/3/6477] Building CXX object tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/fold-character.cpp.o
123.831 [601/2/6478] Building CXX object tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/fold-complex.cpp.o
131.258 [601/1/6479] Building CXX object tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/check-expression.cpp.o
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/154865