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

Mon Sep 1 22:03:43 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-with-thin-lto-ubuntu` running on `as-worker-92` while building `llvm` at step 6 "build-stage1-compiler".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/127/builds/4604

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

```
Step 6 (build-stage1-compiler) failure: build (failure)
...
355.770 [3847/72/2754] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIFormMemoryClauses.cpp.o
356.182 [3846/72/2755] Building CXX object lib/Target/PowerPC/CMakeFiles/LLVMPowerPCCodeGen.dir/PPCExpandAtomicPseudoInsts.cpp.o
356.389 [3845/72/2756] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIModeRegister.cpp.o
356.566 [3844/72/2757] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIModeRegisterDefaults.cpp.o
356.647 [3843/72/2758] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIFoldOperands.cpp.o
356.762 [3842/72/2759] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILoadStoreOptimizer.cpp.o
356.829 [3841/72/2760] Building CXX object lib/Target/PowerPC/CMakeFiles/LLVMPowerPCCodeGen.dir/PPCEarlyReturn.cpp.o
357.104 [3840/72/2761] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/GCNSchedStrategy.cpp.o
357.412 [3839/72/2762] Building CXX object lib/Target/PowerPC/CMakeFiles/LLVMPowerPCCodeGen.dir/PPCMachineFunctionInfo.cpp.o
357.630 [3838/72/2763] Building CXX object lib/Target/AMDGPU/Disassembler/CMakeFiles/LLVMAMDGPUDisassembler.dir/AMDGPUDisassembler.cpp.o
FAILED: lib/Target/AMDGPU/Disassembler/CMakeFiles/LLVMAMDGPUDisassembler.dir/AMDGPUDisassembler.cpp.o 
/usr/bin/c++ -DGTEST_HAS_RTTI=0 -D_GLIBCXX_USE_CXX11_ABI=1 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/lib/Target/AMDGPU/Disassembler -I/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/lib/Target/AMDGPU/Disassembler -I/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/lib/Target/AMDGPU -I/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/lib/Target/AMDGPU -I/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/include -I/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/include -I/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/lib/Target/AMDGPU/Disassembler/.. -I/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/lib/Target/AMDGPU/Disassembler/.. -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 -fvisibility=hidden  -fno-exceptions -funwind-tables -fno-rtti -std=c++17 -MD -MT lib/Target/AMDGPU/Disassembler/CMakeFiles/LLVMAMDGPUDisassembler.dir/AMDGPUDisassembler.cpp.o -MF lib/Target/AMDGPU/Disassembler/CMakeFiles/LLVMAMDGPUDisassembler.dir/AMDGPUDisassembler.cpp.o.d -o lib/Target/AMDGPU/Disassembler/CMakeFiles/LLVMAMDGPUDisassembler.dir/AMDGPUDisassembler.cpp.o -c /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp
/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp:451: error: explicit template specialization cannot have a storage class
  451 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint32_t> = 32;
      | 
/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp:452: error: explicit template specialization cannot have a storage class
  452 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint64_t> = 64;
      | 
/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp:454: error: explicit template specialization cannot have a storage class
  454 | static constexpr uint32_t llvm::MCD::InsnBitWidth<std::bitset<96>> = 96;
      | 
/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp:456: error: explicit template specialization cannot have a storage class
  456 | static constexpr uint32_t llvm::MCD::InsnBitWidth<std::bitset<128>> = 128;
      | 
357.700 [3838/71/2764] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/R600ISelDAGToDAG.cpp.o
357.741 [3838/70/2765] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILateBranchLowering.cpp.o
357.815 [3838/69/2766] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIShrinkInstructions.cpp.o
357.934 [3838/68/2767] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIMemoryLegalizer.cpp.o
358.118 [3838/67/2768] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILowerSGPRSpills.cpp.o
358.236 [3838/66/2769] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILowerControlFlow.cpp.o
358.332 [3838/65/2770] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIFrameLowering.cpp.o
358.367 [3838/64/2771] Building CXX object lib/Target/PowerPC/CMakeFiles/LLVMPowerPCCodeGen.dir/PPCTargetObjectFile.cpp.o
358.374 [3838/63/2772] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIMachineScheduler.cpp.o
358.606 [3838/62/2773] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIPeepholeSDWA.cpp.o
358.622 [3838/61/2774] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIOptimizeExecMaskingPreRA.cpp.o
359.206 [3838/60/2775] Building CXX object lib/Target/PowerPC/MCTargetDesc/CMakeFiles/LLVMPowerPCDesc.dir/PPCMCAsmInfo.cpp.o
359.611 [3838/59/2776] Building CXX object lib/Target/PowerPC/CMakeFiles/LLVMPowerPCCodeGen.dir/PPCBranchSelector.cpp.o
359.875 [3838/58/2777] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIPreAllocateWWMRegs.cpp.o
359.958 [3838/57/2778] Building CXX object lib/Target/PowerPC/CMakeFiles/LLVMPowerPCCodeGen.dir/PPCCTRLoops.cpp.o
360.052 [3838/56/2779] Building CXX object lib/Target/PowerPC/CMakeFiles/LLVMPowerPCCodeGen.dir/PPCBoolRetToInt.cpp.o
360.279 [3838/55/2780] Building CXX object lib/Target/PowerPC/MCTargetDesc/CMakeFiles/LLVMPowerPCDesc.dir/PPCInstPrinter.cpp.o
360.374 [3838/54/2781] Building CXX object lib/Target/AMDGPU/MCTargetDesc/CMakeFiles/LLVMAMDGPUDesc.dir/AMDGPUInstPrinter.cpp.o
360.532 [3838/53/2782] Building CXX object lib/Target/PowerPC/CMakeFiles/LLVMPowerPCCodeGen.dir/PPCHazardRecognizers.cpp.o
360.623 [3838/52/2783] Building CXX object lib/Target/PowerPC/CMakeFiles/LLVMPowerPCCodeGen.dir/GISel/PPCLegalizerInfo.cpp.o
360.675 [3838/51/2784] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIOptimizeVGPRLiveRange.cpp.o
360.763 [3838/50/2785] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIMachineFunctionInfo.cpp.o
360.787 [3838/49/2786] Building CXX object lib/Target/PowerPC/CMakeFiles/LLVMPowerPCCodeGen.dir/PPCCallingConv.cpp.o
361.100 [3838/48/2787] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/AMDGPUInstructionSelector.cpp.o
361.422 [3838/47/2788] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/R600ISelLowering.cpp.o

```

</details>

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