SLPVectorizer creates invalid IR for reduction: Instruction does not dominate all uses!

[TatyanaDoubts]

Godbolt repro: https://godbolt.org/z/P7j1z1T1P
Run clang++ -O3 on the following test:
Test.zip

Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -O3 <source>
1.	<eof> parser at end of file
2.	Optimizer
 #0 0x000055b4b1eb1d44 PrintStackTraceSignalHandler(void*) Signals.cpp:0:0
 #1 0x000055b4b1eafadc llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3fc8adc)
 #2 0x000055b4b1deae78 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007f1e46b84420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #4 0x00007f1e4665100b raise (/lib/x86_64-linux-gnu/libc.so.6+0x4300b)
 #5 0x00007f1e46630859 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22859)
 #6 0x00007f1e46630729 (/lib/x86_64-linux-gnu/libc.so.6+0x22729)
 #7 0x00007f1e46641fd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
 #8 0x000055b4b1f79d1d (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4092d1d)
 #9 0x000055b4b1f79d8b llvm::formLCSSARecursively(llvm::Loop&, llvm::DominatorTree const&, llvm::LoopInfo const*, llvm::ScalarEvolution*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4092d8b)
#10 0x000055b4b1f79d71 llvm::formLCSSARecursively(llvm::Loop&, llvm::DominatorTree const&, llvm::LoopInfo const*, llvm::ScalarEvolution*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4092d71)
#11 0x000055b4b1f79d71 llvm::formLCSSARecursively(llvm::Loop&, llvm::DominatorTree const&, llvm::LoopInfo const*, llvm::ScalarEvolution*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4092d71)
#12 0x000055b4b1c74fdd llvm::LoopUnrollPass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3d8dfdd)
#13 0x000055b4b33d8ca6 llvm::detail::PassModel<llvm::Function, llvm::LoopUnrollPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x54f1ca6)
#14 0x000055b4af6d3884 llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x17ec884)
#15 0x000055b4b165032f llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x376932f)
#16 0x000055b4af6b97c6 llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x17d27c6)
#17 0x000055b4b164e48a llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x376748a)
#18 0x000055b4b2287ac0 (anonymous namespace)::EmitAssemblyHelper::RunOptimizationPipeline(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>&, std::unique_ptr<llvm::ToolOutputFile, std::default_delete<llvm::ToolOutputFile>>&) BackendUtil.cpp:0:0
#19 0x000055b4b228a052 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x43a3052)
#20 0x000055b4b31e6ffb clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x52ffffb)
#21 0x000055b4b4484db5 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x659ddb5)
#22 0x000055b4b31e5aa8 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x52feaa8)
#23 0x000055b4b2a76b09 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4b8fb09)
#24 0x000055b4b29fd58e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4b1658e)
#25 0x000055b4b2b5bd83 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4c74d83)
#26 0x000055b4af358e34 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x1471e34)
#27 0x000055b4af354c37 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) driver.cpp:0:0
#28 0x000055b4b2867479 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#29 0x000055b4b1deb61a llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f0461a)
#30 0x000055b4b2867ccf clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#31 0x000055b4b2830ff9 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4949ff9)
#32 0x000055b4b2831a7d clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x494aa7d)
#33 0x000055b4b283b51c clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x495451c)
#34 0x000055b4af357422 clang_main(int, char**) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x1470422)
#35 0x00007f1e46632083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#36 0x000055b4af35056e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x146956e)
clang-16: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134

[fhahn]

Looks like the issue is that SLPVectorizer generates invalid IR for https://godbolt.org/z/bj8e1soo4

define i8 @test() {
entry:
  br label %for.body

for.body:
  %sum = phi i32 [ %add285.19, %for.body ], [ 0, %entry ]
  %call278 = call i32 @fn(i32 %sum)
  %add285.13 = add i32 %call278, %call278
  %add285.14 = add i32 %add285.13, %call278
  %add285.15 = add i32 %add285.14, %call278
  %add285.16 = add i32 %add285.15, %call278
  %add285.17 = add i32 %add285.16, %call278
  %add285.18 = add i32 %add285.17, %call278
  %add285.19 = add i32 %add285.18, %call278
  br label %for.body
}

declare i32 @fn(i32)

cc @alexey-bataev

[alexey-bataev]

Fixed in 2f8f17c