[llvm] [VPlan] Remove no-op SCALAR-STEPS after unrolling. (PR #123655)

Tue Mar 25 06:09:47 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `polly-x86_64-linux-shlib-plugin` running on `polly-x86_64-gce2` while building `llvm` at step 5 "build".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/75/builds/5767

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

```
Step 5 (build) failure: 'ninja' (failure)
...
[19/153] Linking CXX executable bin/llvm-config
[20/153] Linking CXX static library lib/libLLVMObject.a
[21/153] Linking CXX static library lib/libLLVMVectorize.a
[22/153] Linking CXX static library lib/libLLVMAsmPrinter.a
[23/153] Linking CXX static library lib/libLLVMLTO.a
[24/153] Linking CXX executable bin/lli-child-target
[25/153] Linking CXX executable bin/obj2yaml
[26/153] Linking CXX executable bin/yaml2obj
[27/153] Linking CXX executable bin/llvm-exegesis
[28/153] Linking CXX shared library lib/libLLVM.so.21.0git
FAILED: lib/libLLVM.so.21.0git 
: && /usr/bin/c++ -fPIC -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  -Wl,-z,defs -Wl,-z,nodelete -fuse-ld=lld -Wl,--color-diagnostics   -Wl,--gc-sections  -Wl,-Bsymbolic-functions -shared -Wl,-soname,libLLVM.so.21.0git -o lib/libLLVM.so.21.0git tools/llvm-shlib/CMakeFiles/LLVM.dir/libllvm.cpp.o  -Wl,-rpath,"\$ORIGIN/../lib:"  -Wl,--version-script,/home/worker/buildbot-workers/polly-x86_64-gce2/rundir/llvm.obj/./lib/tools/llvm-shlib/simple_version_script.map  -Wl,--whole-archive  lib/libLLVMDemangle.a  lib/libLLVMSupport.a  lib/libLLVMCore.a  lib/libLLVMFuzzerCLI.a  lib/libLLVMFuzzMutate.a  lib/libLLVMFileCheck.a  lib/libLLVMInterfaceStub.a  lib/libLLVMIRPrinter.a  lib/libLLVMIRReader.a  lib/libLLVMCGData.a  lib/libLLVMCodeGen.a  lib/libLLVMSelectionDAG.a  lib/libLLVMAsmPrinter.a  lib/libLLVMMIRParser.a  lib/libLLVMGlobalISel.a  lib/libLLVMCodeGenTypes.a  lib/libLLVMBinaryFormat.a  lib/libLLVMBitReader.a  lib/libLLVMBitWriter.a  lib/libLLVMBitstreamReader.a  lib/libLLVMDWARFLinker.a  lib/libLLVMDWARFLinkerClassic.a  lib/libLLVMDWARFLinkerParallel.a  lib/libLLVMExtensions.a  lib/libLLVMFrontendAtomic.a  lib/libLLVMFrontendDriver.a  lib/libLLVMFrontendHLSL.a  lib/libLLVMFrontendOpenACC.a  lib/libLLVMFrontendOpenMP.a  lib/libLLVMFrontendOffloading.a  lib/libLLVMTransformUtils.a  lib/libLLVMInstrumentation.a  lib/libLLVMAggressiveInstCombine.a  lib/libLLVMInstCombine.a  lib/libLLVMScalarOpts.a  lib/libLLVMipo.a  lib/libLLVMVectorize.a  lib/libLLVMObjCARCOpts.a  lib/libLLVMCoroutines.a  lib/libLLVMCFGuard.a  lib/libLLVMHipStdPar.a  lib/libLLVMLinker.a  lib/libLLVMAnalysis.a  lib/libLLVMLTO.a  lib/libLLVMMC.a  lib/libLLVMMCParser.a  lib/libLLVMMCDisassembler.a  lib/libLLVMMCA.a  lib/libLLVMObjCopy.a  lib/libLLVMObject.a  lib/libLLVMObjectYAML.a  lib/libLLVMOption.a  lib/libLLVMRemarks.a  lib/libLLVMDebugInfoDWARF.a  lib/libLLVMDebugInfoGSYM.a  lib/libLLVMDebugInfoLogicalView.a  lib/libLLVMDebugInfoMSF.a  lib/libLLVMDebugInfoCodeView.a  lib/libLLVMDebugInfoPDB.a  lib/libLLVMSymbolize.a  lib/libLLVMDebugInfoBTF.a  lib/libLLVMDWP.a  lib/libLLVMExecutionEngine.a  lib/libLLVMInterpreter.a  lib/libLLVMJITLink.a  lib/libLLVMMCJIT.a  lib/libLLVMOrcJIT.a  lib/libLLVMOrcDebugging.a  lib/libLLVMOrcShared.a  lib/libLLVMOrcTargetProcess.a  lib/libLLVMRuntimeDyld.a  lib/libLLVMTarget.a  lib/libLLVMX86CodeGen.a  lib/libLLVMX86AsmParser.a  lib/libLLVMX86Disassembler.a  lib/libLLVMX86TargetMCA.a  lib/libLLVMX86Desc.a  lib/libLLVMX86Info.a  lib/libLLVMNVPTXCodeGen.a  lib/libLLVMNVPTXDesc.a  lib/libLLVMNVPTXInfo.a  lib/libLLVMSandboxIR.a  lib/libLLVMAsmParser.a  lib/libLLVMLineEditor.a  lib/libLLVMProfileData.a  lib/libLLVMCoverage.a  lib/libLLVMPasses.a  lib/libLLVMTargetParser.a  lib/libLLVMTextAPI.a  lib/libLLVMTextAPIBinaryReader.a  lib/libLLVMTelemetry.a  lib/libLLVMDlltoolDriver.a  lib/libLLVMLibDriver.a  lib/libLLVMXRay.a  lib/libLLVMWindowsDriver.a  lib/libLLVMWindowsManifest.a  -Wl,--no-whole-archive  lib/libLLVMDWARFLinker.a  lib/libLLVMExtensions.a  lib/libLLVMOrcJIT.a  lib/libLLVMExecutionEngine.a  lib/libLLVMJITLink.a  lib/libLLVMOrcTargetProcess.a  lib/libLLVMRuntimeDyld.a  lib/libLLVMPasses.a  lib/libLLVMCoroutines.a  lib/libLLVMHipStdPar.a  lib/libLLVMWindowsDriver.a  lib/libLLVMOrcShared.a  lib/libLLVMIRPrinter.a  lib/libLLVMGlobalISel.a  lib/libLLVMCFGuard.a  lib/libLLVMMCA.a  lib/libLLVMMCDisassembler.a  lib/libLLVMSelectionDAG.a  lib/libLLVMAsmPrinter.a  lib/libLLVMCodeGen.a  lib/libLLVMCGData.a  lib/libLLVMObjCARCOpts.a  lib/libLLVMCodeGenTypes.a  lib/libLLVMipo.a  lib/libLLVMBitWriter.a  lib/libLLVMFrontendOpenMP.a  lib/libLLVMFrontendAtomic.a  lib/libLLVMFrontendOffloading.a  lib/libLLVMObjectYAML.a  lib/libLLVMInstrumentation.a  lib/libLLVMScalarOpts.a  lib/libLLVMAggressiveInstCombine.a  lib/libLLVMInstCombine.a  lib/libLLVMLinker.a  lib/libLLVMVectorize.a  lib/libLLVMTransformUtils.a  lib/libLLVMSandboxIR.a  lib/libLLVMTarget.a  lib/libLLVMAnalysis.a  lib/libLLVMProfileData.a  lib/libLLVMSymbolize.a  lib/libLLVMDebugInfoPDB.a  lib/libLLVMDebugInfoMSF.a  lib/libLLVMDebugInfoCodeView.a  lib/libLLVMDebugInfoBTF.a  lib/libLLVMDebugInfoDWARF.a  lib/libLLVMOption.a  lib/libLLVMObject.a  lib/libLLVMIRReader.a  lib/libLLVMAsmParser.a  lib/libLLVMBitReader.a  lib/libLLVMCore.a  lib/libLLVMRemarks.a  lib/libLLVMBitstreamReader.a  lib/libLLVMMCParser.a  lib/libLLVMMC.a  lib/libLLVMTextAPI.a  lib/libLLVMBinaryFormat.a  lib/libLLVMTargetParser.a  lib/libLLVMSupport.a  lib/libLLVMDemangle.a  -lrt  -ldl  -lm  /usr/lib/x86_64-linux-gnu/libz.so  /usr/lib/x86_64-linux-gnu/libxml2.so && :
ld.lld: error: undefined symbol: llvm::VPUnrollPartAccessor<2u>::getUnrollPart(llvm::VPUser&) const
>>> referenced by VPlanTransforms.cpp
>>>               VPlanTransforms.cpp.o:(llvm::VPlanTransforms::simplifyRecipes(llvm::VPlan&, llvm::Type&) (.localalias)) in archive lib/libLLVMVectorize.a
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/123655