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

Sun Mar 23 04:30:17 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `mlir-rocm-mi200` running on `mi200-buildbot` while building `llvm` at step 6 "build-check-mlir-build-only".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/177/builds/15120

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

```
Step 6 (build-check-mlir-build-only) failure: build (failure)
...
31.468 [2584/58/2265] Building CXX object lib/Transforms/InstCombine/CMakeFiles/LLVMInstCombine.dir/InstCombineShifts.cpp.o
31.473 [2583/58/2266] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/AlignmentFromAssumptions.cpp.o
31.483 [2582/58/2267] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/ADCE.cpp.o
31.495 [2581/58/2268] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/AnnotationRemarks.cpp.o
31.497 [2580/58/2269] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/BDCE.cpp.o
31.499 [2579/58/2270] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/ConstantHoisting.cpp.o
31.500 [2578/58/2271] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/CallSiteSplitting.cpp.o
31.509 [2577/58/2272] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/ConstraintElimination.cpp.o
31.510 [2576/58/2273] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/CorrelatedValuePropagation.cpp.o
31.512 [2575/58/2274] Building CXX object lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/TargetInstrInfo.cpp.o
FAILED: lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/TargetInstrInfo.cpp.o 
CCACHE_CPP2=yes CCACHE_HASHDIR=yes /usr/bin/ccache /usr/bin/clang++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/vol/worker/mi200-buildbot/mlir-rocm-mi200/build/lib/CodeGen -I/vol/worker/mi200-buildbot/mlir-rocm-mi200/llvm-project/llvm/lib/CodeGen -I/vol/worker/mi200-buildbot/mlir-rocm-mi200/build/include -I/vol/worker/mi200-buildbot/mlir-rocm-mi200/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -std=c++17 -MD -MT lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/TargetInstrInfo.cpp.o -MF lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/TargetInstrInfo.cpp.o.d -o lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/TargetInstrInfo.cpp.o -c /vol/worker/mi200-buildbot/mlir-rocm-mi200/llvm-project/llvm/lib/CodeGen/TargetInstrInfo.cpp
/vol/worker/mi200-buildbot/mlir-rocm-mi200/llvm-project/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());
      |                             ^~~~~~~~~~~~~~~~~
/vol/worker/mi200-buildbot/mlir-rocm-mi200/llvm-project/llvm/lib/CodeGen/TargetInstrInfo.cpp:1021:35: note: passing argument to parameter 'InstrIdxForVirtReg' here
 1021 |     DenseMap<unsigned, unsigned> &InstrIdxForVirtReg,
      |                                   ^
1 error generated.
31.512 [2575/57/2275] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/DCE.cpp.o
31.515 [2575/56/2276] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/DeadStoreElimination.cpp.o
31.529 [2575/55/2277] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/DFAJumpThreading.cpp.o
31.535 [2575/54/2278] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/FlattenCFGPass.cpp.o
31.541 [2575/53/2279] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/DivRemPairs.cpp.o
31.547 [2575/52/2280] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/GuardWidening.cpp.o
31.548 [2575/51/2281] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/Float2Int.cpp.o
31.550 [2575/50/2282] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/EarlyCSE.cpp.o
31.555 [2575/49/2283] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/GVN.cpp.o
31.555 [2575/48/2284] Building CXX object lib/Transforms/Scalar/CMakeFiles/LLVMScalarOpts.dir/GVNHoist.cpp.o
31.612 [2575/47/2285] Building CXX object lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/MachineOutliner.cpp.o
31.742 [2575/46/2286] Building CXX object lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/ScheduleDAGInstrs.cpp.o
31.906 [2575/45/2287] Building CXX object lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/VLIWMachineScheduler.cpp.o
31.933 [2575/44/2288] Building CXX object lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/SplitKit.cpp.o
32.287 [2575/43/2289] Building CXX object lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/RegAllocGreedy.cpp.o
32.750 [2575/42/2290] Building CXX object lib/CodeGen/SelectionDAG/CMakeFiles/LLVMSelectionDAG.dir/ScheduleDAGVLIW.cpp.o
32.770 [2575/41/2291] Building CXX object lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/MachineScheduler.cpp.o
33.244 [2575/40/2292] Building CXX object lib/CodeGen/SelectionDAG/CMakeFiles/LLVMSelectionDAG.dir/ScheduleDAGFast.cpp.o
33.247 [2575/39/2293] Building CXX object lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/MachineVerifier.cpp.o
33.257 [2575/38/2294] Building CXX object lib/CodeGen/SelectionDAG/CMakeFiles/LLVMSelectionDAG.dir/ResourcePriorityQueue.cpp.o
33.879 [2575/37/2295] Building CXX object lib/CodeGen/SelectionDAG/CMakeFiles/LLVMSelectionDAG.dir/InstrEmitter.cpp.o
33.916 [2575/36/2296] Building CXX object lib/CodeGen/SelectionDAG/CMakeFiles/LLVMSelectionDAG.dir/FunctionLoweringInfo.cpp.o
33.925 [2575/35/2297] Building CXX object lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/TwoAddressInstructionPass.cpp.o
34.340 [2575/34/2298] Building AMDGPUGenMCPseudoLowering.inc...
34.898 [2575/33/2299] Building CXX object lib/CodeGen/SelectionDAG/CMakeFiles/LLVMSelectionDAG.dir/ScheduleDAGSDNodes.cpp.o
35.040 [2575/32/2300] Building CXX object lib/CodeGen/SelectionDAG/CMakeFiles/LLVMSelectionDAG.dir/SelectionDAGDumper.cpp.o
35.077 [2575/31/2301] Building AMDGPUGenCallingConv.inc...
35.308 [2575/30/2302] Building CXX object lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/WindowScheduler.cpp.o
35.617 [2575/29/2303] Building CXX object lib/CodeGen/SelectionDAG/CMakeFiles/LLVMSelectionDAG.dir/ScheduleDAGRRList.cpp.o
36.153 [2575/28/2304] Building AMDGPUGenPostLegalizeGICombiner.inc...

```

</details>

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