[llvm] [LoopVectorize] Fix crash with GC statepoint in epilogue vectorization (PR #179459)

Tue Feb 3 06:21:53 PST 2026

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Linux-->
# :penguin: Linux x64 Test Results

* 169117 tests passed
* 3028 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### LLVM
<details>
<summary>LLVM.Transforms/LoopVectorize/pr179407-gc-statepoint.ll</summary>

```
Exit Code: 2

Command Output (stdout):
--
# RUN: at line 1
/home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/opt -passes=loop-vectorize -enable-epilogue-vectorization -force-vector-width=2 -epilogue-vectorization-force-VF=2 -S < /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/LoopVectorize/pr179407-gc-statepoint.ll | /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/FileCheck /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/LoopVectorize/pr179407-gc-statepoint.ll
# executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/opt -passes=loop-vectorize -enable-epilogue-vectorization -force-vector-width=2 -epilogue-vectorization-force-VF=2 -S
# .---command stderr------------
# | opt: /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include/llvm/Support/Casting.h:109: static bool llvm::isa_impl_cl<llvm::VPReductionPHIRecipe, const llvm::VPRecipeBase *>::doit(const From *) [To = llvm::VPReductionPHIRecipe, From = const llvm::VPRecipeBase *]: Assertion `Val && "isa<> used on a null pointer"' failed.
# | PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
# | Stack dump:
# | 0.	Program arguments: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/opt -passes=loop-vectorize -enable-epilogue-vectorization -force-vector-width=2 -epilogue-vectorization-force-VF=2 -S
# | 1.	Running pass "function(loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>)" on module "<stdin>"
# | 2.	Running pass "loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>" on function "wombat"
# |  #0 0x0000000004f62368 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/Support/Unix/Signals.inc:842:13
# |  #1 0x0000000004f5f985 llvm::sys::RunSignalHandlers() /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/Support/Signals.cpp:109:18
# |  #2 0x0000000004f63421 SignalHandler(int, siginfo_t*, void*) /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/Support/Unix/Signals.inc:429:38
# |  #3 0x00007e45d3f0c330 (/lib/x86_64-linux-gnu/libc.so.6+0x45330)
# |  #4 0x00007e45d3f65b2c pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x9eb2c)
# |  #5 0x00007e45d3f0c27e raise (/lib/x86_64-linux-gnu/libc.so.6+0x4527e)
# |  #6 0x00007e45d3eef8ff abort (/lib/x86_64-linux-gnu/libc.so.6+0x288ff)
# |  #7 0x00007e45d3eef81b (/lib/x86_64-linux-gnu/libc.so.6+0x2881b)
# |  #8 0x00007e45d3f02517 (/lib/x86_64-linux-gnu/libc.so.6+0x3b517)
# |  #9 0x00000000065da5f6 cast_if_present<llvm::BasicBlock, llvm::Value> /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include/llvm/Support/Casting.h:700:3
# | #10 0x00000000065da5f6 cast_or_null<llvm::BasicBlock, llvm::Value> /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include/llvm/Support/Casting.h:723:10
# | #11 0x00000000065da5f6 getSuccessor /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include/llvm/IR/Instructions.h:3148:12
# | #12 0x00000000065da5f6 connectEpilogueVectorLoop(llvm::VPlan&, llvm::Loop*, llvm::EpilogueLoopVectorizationInfo&, llvm::DominatorTree*, llvm::LoopVectorizationLegality&, llvm::DenseMap<llvm::SCEV const*, llvm::Value*, llvm::DenseMapInfo<llvm::SCEV const*, void>, llvm::detail::DenseMapPair<llvm::SCEV const*, llvm::Value*>>&, (anonymous namespace)::GeneratedRTChecks&, llvm::ArrayRef<llvm::Instruction*>) /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:9406:13
# | #13 0x00000000065d12dd llvm::LoopVectorizePass::processLoop(llvm::Loop*) /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:9905:5
# | #14 0x00000000065db4bb llvm::LoopVectorizePass::runImpl(llvm::Function&) /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:9971:27
# | #15 0x00000000065dbd64 llvm::LoopVectorizePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:10009:32
# | #16 0x000000000649295d llvm::detail::PassModel<llvm::Function, llvm::LoopVectorizePass, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:91:5
# | #17 0x000000000517dd07 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include/llvm/IR/PassManagerImpl.h:80:8
# | #18 0x000000000648fefd llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:91:5
# | #19 0x00000000051827a1 llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/IR/PassManager.cpp:132:23
# | #20 0x000000000641fd6d llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:91:5
# | #21 0x000000000517cac7 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include/llvm/IR/PassManagerImpl.h:80:8
# | #22 0x00000000064181f2 ~SmallPtrSetImplBase /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include/llvm/ADT/SmallPtrSet.h:89:9
# | #23 0x00000000064181f2 ~PreservedAnalyses /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include/llvm/IR/Analysis.h:112:7
# | #24 0x00000000064181f2 llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::PassPlugin>, llvm::ArrayRef<std::function<void (llvm::PassBuilder&)>>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool, bool, bool, bool) /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/tools/opt/NewPMDriver.cpp:574:3
# | #25 0x0000000004f029ad optMain /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/tools/opt/optdriver.cpp:0:10
# | #26 0x00007e45d3ef11ca (/lib/x86_64-linux-gnu/libc.so.6+0x2a1ca)
# | #27 0x00007e45d3ef128b __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2a28b)
# | #28 0x0000000004efbca5 _start (/home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/opt+0x4efbca5)
# `-----------------------------
# error: command failed with exit status: -6
# executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/FileCheck /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/LoopVectorize/pr179407-gc-statepoint.ll
# .---command stderr------------
# | FileCheck error: '<stdin>' is empty.
# | FileCheck command line:  /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/FileCheck /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/LoopVectorize/pr179407-gc-statepoint.ll
# `-----------------------------
# error: command failed with exit status: 2

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/179459