[SLPVectorizer] Instruction does not dominate all uses! LLVM ERROR: Broken module found, compilation aborted!

[TatyanaDoubts]

To reproduce run the following test with -passes slp-vectorizer -slp-threshold=-99999
Test.ll.tgz

Reproducer : https://godbolt.org/z/GW41a7WP6

Stack dump:

Instruction does not dominate all uses!
  %2 = shufflevector <2 x ptr addrspace(1)> %0, <2 x ptr addrspace(1)> poison, <2 x i32> <i32 1, i32 0>
  %1 = extractelement <2 x ptr addrspace(1)> %2, i32 0
LLVM ERROR: Broken module found, compilation aborted!
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/opt -o /app/output.s -S -passes slp-vectorizer -slp-threshold=-99999 <source>
1.	Running pass "verify" on module "<source>"
 #0 0x0000000004eff778 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x4eff778)
 #1 0x0000000004efceec SignalHandler(int) Signals.cpp:0:0
 #2 0x00007c0269e42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #3 0x00007c0269e969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #4 0x00007c0269e42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #5 0x00007c0269e287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #6 0x00000000007b3ff7 llvm::json::operator==(llvm::json::Value const&, llvm::json::Value const&) (.cold) JSON.cpp:0:0
 #7 0x0000000004e396a8 (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x4e396a8)
 #8 0x0000000004d360f0 llvm::VerifierPass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x4d360f0)
 #9 0x00000000008d865e llvm::detail::PassModel<llvm::Module, llvm::VerifierPass, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x8d865e)
#10 0x0000000004cf9c90 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x4cf9c90)
#11 0x00000000008e33d2 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) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x8e33d2)
#12 0x00000000008d62fc optMain (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x8d62fc)
#13 0x00007c0269e29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#14 0x00007c0269e29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#15 0x00000000008cd75e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x8cd75e)
Program terminated with signal: SIGSEGV
Compiler returned: 139

[Zentrik]

@alexey-bataev Hi, is there a way to backport this fix for llvm 19, I tried just cherry picking f70f122 but I ended up getting assertion failures of the form /workspace/srcdir/llvm-project/llvm/lib/IR/Instruction.cpp:321: bool llvm::Instruction::comesBefore(const llvm::Instruction*) const: Assertion 'getParent() == Other->getParent() && "cross-BB instruction order comparison"' failed.'.
I can create an IR reproducer for that failure if need be.
Thank you.

EDIT: Would just adding a check that they're in the same basic block work?

[alexey-bataev]

@alexey-bataev Hi, is there a way to backport this fix for llvm 19, I tried just cherry picking f70f122 but I ended up getting assertion failures of the form /workspace/srcdir/llvm-project/llvm/lib/IR/Instruction.cpp:321: bool llvm::Instruction::comesBefore(const llvm::Instruction*) const: Assertion 'getParent() == Other->getParent() && "cross-BB instruction order comparison"' failed.'. I can create an IR reproducer for that failure if need be. Thank you.

EDIT: Would just adding a check that they're in the same basic block work?

Yes, check for the same parent should fix it