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

Sun Mar 23 04:58:50 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-cmake-x86_64-avx512-win` running on `avx512-intel64-win` while building `llvm` at step 5 "build stage 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/81/builds/5555

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

```
Step 5 (build stage 1) failure: 'ninja' (failure)
...
[1553/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\SwitchLoweringUtils.cpp.obj
[1554/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\SafeStack.cpp.obj
[1555/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\WasmEHPrepare.cpp.obj
[1556/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\SelectionDAGTargetInfo.cpp.obj
[1557/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\XRayInstrumentation.cpp.obj
[1558/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\SelectOptimize.cpp.obj
[1559/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\TargetPassConfig.cpp.obj
[1560/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\VirtRegMap.cpp.obj
[1561/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\TargetRegisterInfo.cpp.obj
[1562/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\TargetInstrInfo.cpp.obj
FAILED: lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/TargetInstrInfo.cpp.obj 
C:\Intel\oneAPI\compiler\latest\bin\icx.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 -ID:\buildbot\llvm-worker\clang-cmake-x86_64-avx512-win\stage1\lib\CodeGen -ID:\buildbot\llvm-worker\clang-cmake-x86_64-avx512-win\llvm\llvm\lib\CodeGen -ID:\buildbot\llvm-worker\clang-cmake-x86_64-avx512-win\stage1\include -ID:\buildbot\llvm-worker\clang-cmake-x86_64-avx512-win\llvm\llvm\include -march=cascadelake /Zc:inline /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 /Ob0 /Od /RTC1 -Qstd:c++17 -MDd -Zi  /EHs-c- /GR- -QMD -QMT lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\TargetInstrInfo.cpp.obj -QMF lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\TargetInstrInfo.cpp.obj.d /Folib\CodeGen\CMakeFiles\LLVMCodeGen.dir\TargetInstrInfo.cpp.obj /Fdlib\CodeGen\CMakeFiles\LLVMCodeGen.dir\LLVMCodeGen.pdb -c D:\buildbot\llvm-worker\clang-cmake-x86_64-avx512-win\llvm\llvm\lib\CodeGen\TargetInstrInfo.cpp
D:\buildbot\llvm-worker\clang-cmake-x86_64-avx512-win\llvm\llvm\lib\CodeGen\TargetInstrInfo.cpp(1514,29): error: non-const lvalue reference to type 'DenseMap<unsigned int, [...]>' cannot bind to a value of unrelated type 'DenseMap<Register, [...]>'
 1514 |                             InstIdxForVirtReg, Root.getOperand(0).getReg());
      |                             ^~~~~~~~~~~~~~~~~
D:\buildbot\llvm-worker\clang-cmake-x86_64-avx512-win\llvm\llvm\lib\CodeGen\TargetInstrInfo.cpp(1021,35): note: passing argument to parameter 'InstrIdxForVirtReg' here

 1021 |     DenseMap<unsigned, unsigned> &InstrIdxForVirtReg,

      |                                   ^

1 error generated.

[1563/4880] Building CXX object lib\CodeGen\AsmPrinter\CMakeFiles\LLVMAsmPrinter.dir\AddressPool.cpp.obj
[1564/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\WinEHPrepare.cpp.obj
[1565/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\StackProtector.cpp.obj
[1566/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\TargetLoweringObjectFileImpl.cpp.obj
[1567/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\LegalizeTypesGeneric.cpp.obj
[1568/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\LegalizeTypes.cpp.obj
[1569/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\TypePromotion.cpp.obj
[1570/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\TwoAddressInstructionPass.cpp.obj
[1571/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\VLIWMachineScheduler.cpp.obj
[1572/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\TargetLoweringBase.cpp.obj
[1573/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\ScheduleDAGVLIW.cpp.obj
[1574/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\LegalizeFloatTypes.cpp.obj
[1575/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\SelectionDAGAddressAnalysis.cpp.obj
[1576/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\InstrEmitter.cpp.obj
[1577/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\FunctionLoweringInfo.cpp.obj
[1578/4880] Building CXX object lib\CodeGen\AsmPrinter\CMakeFiles\LLVMAsmPrinter.dir\ARMException.cpp.obj
[1579/4880] Building CXX object lib\CodeGen\AsmPrinter\CMakeFiles\LLVMAsmPrinter.dir\AIXException.cpp.obj
[1580/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\ResourcePriorityQueue.cpp.obj
[1581/4880] Building CXX object lib\CodeGen\AsmPrinter\CMakeFiles\LLVMAsmPrinter.dir\AsmPrinterDwarf.cpp.obj
[1582/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\SelectionDAGPrinter.cpp.obj
[1583/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\LegalizeIntegerTypes.cpp.obj
[1584/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\LegalizeDAG.cpp.obj
[1585/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\ScheduleDAGFast.cpp.obj
[1586/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\ScheduleDAGRRList.cpp.obj
[1587/4880] Building CXX object lib\CodeGen\CMakeFiles\LLVMCodeGen.dir\WindowScheduler.cpp.obj
[1588/4880] Building CXX object lib\CodeGen\SelectionDAG\CMakeFiles\LLVMSelectionDAG.dir\LegalizeVectorOps.cpp.obj

```

</details>

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