[llvm] [AArch64][MachineCombiner] Reassociate long chains of accumulation instructions into a tree to increase ILP (PR #126060)

Sun Mar 23 04:33:49 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-sie-win` running on `sie-win-worker` while building `llvm` at step 6 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/46/builds/14063

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

```
Step 6 (build-unified-tree) failure: build (failure)
...
[2360/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\JITTargetMachineBuilder.cpp.obj
[2361/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\IRPartitionLayer.cpp.obj
[2362/4857] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\RegAllocFast.cpp.obj
[2363/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\DebugUtils.cpp.obj
[2364/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\OrcABISupport.cpp.obj
[2365/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\JITLinkReentryTrampolines.cpp.obj
[2366/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\EHFrameRegistrationPlugin.cpp.obj
[2367/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\LazyObjectLinkingLayer.cpp.obj
[2368/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\LinkGraphLinkingLayer.cpp.obj
[2369/4857] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\TargetInstrInfo.cpp.obj
FAILED: lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/TargetInstrInfo.cpp.obj 
C:\bin\ccache.exe C:\PROGRA~2\MICROS~1\2019\BUILDT~1\VC\Tools\MSVC\1429~1.301\bin\HostX64\x64\cl.exe  /nologo /TP -DGTEST_HAS_RTTI=0 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_GLIBCXX_ASSERTIONS -D_HAS_EXCEPTIONS=0 -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_UNICODE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -Ilib\CodeGen -IZ:\b\llvm-clang-x86_64-sie-win\llvm-project\llvm\lib\CodeGen -Iinclude -IZ:\b\llvm-clang-x86_64-sie-win\llvm-project\llvm\include /DWIN32 /D_WINDOWS   /Zc:inline /Zc:preprocessor /Zc:__cplusplus /Oi /bigobj /permissive- /W4 -wd4141 -wd4146 -wd4244 -wd4267 -wd4291 -wd4351 -wd4456 -wd4457 -wd4458 -wd4459 -wd4503 -wd4624 -wd4722 -wd4100 -wd4127 -wd4512 -wd4505 -wd4610 -wd4510 -wd4702 -wd4245 -wd4706 -wd4310 -wd4701 -wd4703 -wd4389 -wd4611 -wd4805 -wd4204 -wd4577 -wd4091 -wd4592 -wd4319 -wd4709 -wd5105 -wd4324 -wd4251 -wd4275 -w14062 -we4238 /Gw /O2 /Ob2  -MD  /EHs-c- /GR- -UNDEBUG -std:c++17 /showIncludes /Folib\CodeGen\CMakeFiles\LLVMCodeGen.dir\TargetInstrInfo.cpp.obj /Fdlib\CodeGen\CMakeFiles\LLVMCodeGen.dir\LLVMCodeGen.pdb /FS -c Z:\b\llvm-clang-x86_64-sie-win\llvm-project\llvm\lib\CodeGen\TargetInstrInfo.cpp
Z:\b\llvm-clang-x86_64-sie-win\llvm-project\llvm\lib\CodeGen\TargetInstrInfo.cpp(1513): error C2664: 'void llvm::TargetInstrInfo::reduceAccumulatorTree(llvm::SmallVectorImpl<llvm::Register> &,llvm::SmallVectorImpl<llvm::MachineInstr *> &,llvm::MachineFunction &,llvm::MachineInstr &,llvm::MachineRegisterInfo &,llvm::DenseMap<unsigned int,unsigned int,llvm::DenseMapInfo<unsigned int,void>,llvm::detail::DenseMapPair<KeyT,ValueT>> &,llvm::Register) const': cannot convert argument 6 from 'llvm::DenseMap<llvm::Register,unsigned int,llvm::DenseMapInfo<llvm::Register,void>,llvm::detail::DenseMapPair<KeyT,ValueT>>' to 'llvm::DenseMap<unsigned int,unsigned int,llvm::DenseMapInfo<unsigned int,void>,llvm::detail::DenseMapPair<KeyT,ValueT>> &'
        with
        [
            KeyT=unsigned int,
            ValueT=unsigned int
        ]
        and
        [
            KeyT=llvm::Register,
            ValueT=unsigned int
        ]
        and
        [
            KeyT=unsigned int,
            ValueT=unsigned int
        ]
Z:\b\llvm-clang-x86_64-sie-win\llvm-project\llvm\lib\CodeGen\TargetInstrInfo.cpp(1017): note: see declaration of 'llvm::TargetInstrInfo::reduceAccumulatorTree'
[2370/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\LinkGraphLayer.cpp.obj
[2371/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\LLJIT.cpp.obj
[2372/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\MachO.cpp.obj
[2373/4857] Building CXX object lib\CodeGen\GlobalISel\CMakeFiles\LLVMGlobalISel.dir\MachineIRBuilder.cpp.obj
[2374/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\ObjectTransformLayer.cpp.obj
[2375/4857] Building CXX object lib\ExecutionEngine\Orc\Debugging\CMakeFiles\LLVMOrcDebugging.dir\DebuggerSupport.cpp.obj
[2376/4857] Building CXX object lib\ExecutionEngine\Orc\Debugging\CMakeFiles\LLVMOrcDebugging.dir\DebuggerSupportPlugin.cpp.obj
[2377/4857] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\ScheduleDAG.cpp.obj
[2378/4857] Building CXX object lib\ExecutionEngine\Orc\Debugging\CMakeFiles\LLVMOrcDebugging.dir\PerfSupportPlugin.cpp.obj
[2379/4857] Building CXX object lib\ExecutionEngine\Orc\Debugging\CMakeFiles\LLVMOrcDebugging.dir\LLJITUtilsCBindings.cpp.obj
[2380/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\SimpleRemoteEPC.cpp.obj
[2381/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\SectCreate.cpp.obj
[2382/4857] Building CXX object lib\ExecutionEngine\Orc\Debugging\CMakeFiles\LLVMOrcDebugging.dir\VTuneSupportPlugin.cpp.obj
[2383/4857] Building CXX object lib\ExecutionEngine\Orc\TargetProcess\CMakeFiles\LLVMOrcTargetProcess.dir\ExecutorSharedMemoryMapperService.cpp.obj
[2384/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\LookupAndRecordAddrs.cpp.obj
[2385/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\Speculation.cpp.obj
[2386/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\SpeculateAnalyses.cpp.obj
[2387/4857] Building CXX object lib\ExecutionEngine\Orc\TargetProcess\CMakeFiles\LLVMOrcTargetProcess.dir\JITLoaderGDB.cpp.obj
[2388/4857] Building CXX object lib\ExecutionEngine\Orc\TargetProcess\CMakeFiles\LLVMOrcTargetProcess.dir\DefaultHostBootstrapValues.cpp.obj
[2389/4857] Building CXX object lib\ExecutionEngine\Orc\CMakeFiles\LLVMOrcJIT.dir\MapperJITLinkMemoryManager.cpp.obj

```

</details>

https://github.com/llvm/llvm-project/pull/126060