<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/59781>59781</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            A/F: EltBitwidth % Factor == 0 && "Can not split into this many chunks?" after commit e4d25a9c234b
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          dyung
      </td>
    </tr>
</table>

<pre>
    One of our internal tests recently started to fail and I bisected the issue back to commit e4d25a9c234b. Consider the following code:
```c++
void b();
void c(char, void *, unsigned);
#define d(f, e) c(f, &e, sizeof(e))
struct h {
  h();
 unsigned a : 19;
} g;
void j() {
 __attribute__((__vector_size__(sizeof(long)))) long i;
  d('c', i);
  i *= g.a;
  b();
}
```
If compiled on linux (clang -c test.cpp), it hits an assertion failure:
```
clang++: /root/llvm-project/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:21520: llvm::SDValue {anonymous}::DAGCombiner::convertBuildVecZextToBuildVecWithZeros(llvm::SDNode*): Assertion `EltBitwidth % Factor == 0 && "Can not split into this many chunks?"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -c <source> -L. -Wl,-rpath,. -Wl,-rpath,/opt/compiler-explorer/gcc-snapshot/lib64 -Wl,-rpath,/opt/compiler-explorer/gcc-snapshot/lib32
1.      <eof> parser at end of file
2.      Code generation
3.      Running pass 'Function Pass Manager' on module '<source>'.
4.      Running pass 'X86 DAG->DAG Instruction Selection' on function '@_Z1jv'
 #0 0x00005569d29cb33f llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3fe033f)
 #1 0x00005569d29c92dc llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3fde2dc)
 #2 0x00005569d2923288 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007f26a43e2420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #4 0x00007f26a3eaf00b raise (/lib/x86_64-linux-gnu/libc.so.6+0x4300b)
 #5 0x00007f26a3e8e859 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22859)
 #6 0x00007f26a3e8e729 (/lib/x86_64-linux-gnu/libc.so.6+0x22729)
 #7 0x00007f26a3e9ffd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
 #8 0x00005569d3ab16ba (anonymous namespace)::DAGCombiner::visitBUILD_VECTOR(llvm::SDNode*) DAGCombiner.cpp:0:0
 #9 0x00005569d3abd6f9 (anonymous namespace)::DAGCombiner::visit(llvm::SDNode*) DAGCombiner.cpp:0:0
#10 0x00005569d3abfd55 (anonymous namespace)::DAGCombiner::combine(llvm::SDNode*) DAGCombiner.cpp:0:0
#11 0x00005569d3ac14e0 llvm::SelectionDAG::Combine(llvm::CombineLevel, llvm::AAResults*, llvm::CodeGenOpt::Level) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x50d64e0)
#12 0x00005569d3be40a2 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x51f90a2)
#13 0x00005569d3be7ed8 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x51fced8)
#14 0x00005569d3be9e5f llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (.part.0) SelectionDAGISel.cpp:0:0
#15 0x00005569d149f000 (anonymous namespace)::X86DAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&) X86ISelDAGToDAG.cpp:0:0
#16 0x00005569d1c65fbe llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
#17 0x00005569d2206b85 llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x381bb85)
#18 0x00005569d2206dc9 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x381bdc9)
#19 0x00005569d2207612 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x381c612)
#20 0x00005569d2dd6410 (anonymous namespace)::EmitAssemblyHelper::EmitAssembly(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>) BackendUtil.cpp:0:0
#21 0x00005569d2dd6a75 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+++0x43eba75)
#22 0x00005569d3d4b46b clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x536046b)
#23 0x00005569d503f495 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6654495)
#24 0x00005569d3d49ee8 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x535eee8)
#25 0x00005569d35c40e9 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4bd90e9)
#26 0x00005569d354ab6e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4b5fb6e)
#27 0x00005569d36a9da3 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4cbeda3)
#28 0x00005569cfed46b4 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x14e96b4)
#29 0x00005569cfed07f7 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) driver.cpp:0:0
#30 0x00005569d33b4359 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#31 0x00005569d2923a2a llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f38a2a)
#32 0x00005569d33b4c0f clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#33 0x00005569d337dd9c clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4992d9c)
#34 0x00005569d337e81d 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+++0x499381d)
#35 0x00005569d3387c5c clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x499cc5c)
#36 0x00005569cfed2e32 clang_main(int, char**) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x14e7e32)
#37 0x00007f26a3e90083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#38 0x00005569cfecba9e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x14e0a9e)
```
Here is a link showing the assertion failure on godbolt: https://godbolt.org/z/E9c4f1Kj4

@LebedevRI, since this was your change, can you take a look?
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzkWttz4yiX_2vIC-WUBJIsPeTBsePuzPZsd3Uy_U3NiwvBkU1HBi-gdPL99Vsg2RGO05f5kqmt2iontrgcfud-EDBr5VoBXKD8EuWLM9a5jTYX4rFT67Nai8eLjwqwbrDuDJbKgVGsxQ6ss9gAB-XaR2wdMw4Edho3TLaYKYGvcS0t8NC8ASyt7QDXjN_5UVxvt9JhyATJWcUJzepzPNfKSgEmjG902-pvUq0x1wIQnaFkgZIZKpL-wxG59J_Qeq-lwDUiJSIVouNGjkjJN8wgMsehAZGZ_92pwLYYT0CECmikAiwQKRs_DBCpAo3whEgB_tvKf4NuECl9t_-E6daZjju8wWg6EMR4c4TpsC5mGNEZTkerTxd4HYP_2s8eEVytmHNG1p2D1Sr0lqvVPXCnzcqjCo0HeK1W6wFh-GDfgOUTmsAoIlOOyNQzJiOsWAZp0QVen7NR87Gg0XRxpJz-8brxet7JFgTWCrdSdQ_Y66Nlao0nPFjROd_tAro5lg5vpLOYKcysBeOkVsGeOnPCAPrHQGswBTrDiCyN1g6RZdvebyc7o78C3z_6L1kjspxrAe9AIbK8gRa4X2cxe4fIcjF7N9fbWiowARedkTQniaccCNAZorObxRfWduC1wpRWj1vdWS-C0Dmi0Ddwre7BuMtOtuIL8L_gwd3q_dO_pNv8BUZbr6zRAv_tTd4bauWXnh2EgYrkqnWX0n2Twm0wIjleMq98jOjCKyrxNopIgREhc6aw0g7bXSudd12N3UZavGXqEfNNp-4soktECCLTIGYQ571QP324mt1cYdvV3kkZrrs1NrDTxnnf3Ti3sx4pWSKyXEu36epzrrcjKceyD65vEVmGuCAVbzsBwcm5YXYTgoIzjAff2hnYGc3BWhDY6s70zX4ms1ZzyXxEMZ3Clhu5cwPkG-cji-i2u4OlJOcoqT4ZvTZsi5lZd1tQzg5Wonce2WCeZgIPu1YbML7NW9TkYIB24kyn7hBZ1lLtu3uDw5O1-MZMM8nwZI0n2tNl3pqXunO7zp1bPJmsOZ84rVu-YVJ5LX1vbT_YKrazG-3wpOG61WYiJFsrbZ3kFk8apSdBanEzx4jOB2nRKzz5cI4n_2oRmU_MjrkNIvNnDT8NpHebIvsPCVDSqyX1akF07kMUvcI7ZiwYzBwGJXyeaWQL_UjiR3pfxWtQYJhXR99Dfc_nTimfH3bMWozIdNmp4Mr4k2_4nSm29lCmPvZsteha8KPGckJkOphPdorgn2WBF7N3E0SvFrN3-Fr1Ed4vcYgbA_1mv7ZfIUtWf6Vf7_3PPmIiQhOcPCRJkuR5UQlS8ZrSZhRT7KPtf3wyUrlgzLe9R4zigmHfVto6A2wbvHzunTrkBx-PX8WkEblMHmgDCaXNIbF5_OkR_ooIfgr_vAWmut1HdSPXirWIlIeMN2Sj10crgAgeoSUxWkJJWeK5d5vPwPU9mMce3numROsXLQdJRmPmWjl4cEMmSMLfYQk6LDFtSMEyCiQjCV6tDFinDayMG_jsM85DWayKbBJS4GStur5j5zYGmDi3-jwJvKRZRpKIk2y8DAXWJEmNDZMWfoI-95SLQDmjSVJHlPOYcgllXmFW659CPqJMSJlXEeXimPL0oPWfpjklMc1pTLNqGlH8Gk1KG1FENMuxlVBWp0XNPM1DVseKbcHugh9WL-T3e2mlu_zj-sNi9eVqfvvx84upHD-vLo5sqjoCJIqm-nuA_iYI7-jJEYhG5Pkvg-D9038AI41h8DSDZFyEjQu3PvKcWHJo-wD34FPXaP5s9hls1zo77AfGc0Jx-HHn-udh8qvHrTwRRQZP3u6ZjuIWrSFLGHmB6esbaCPAMyWuttKFQrZ8C7xpUyWMRHjpEd4piPKHePvWWdteMiv5Zav5XVz_HhI518q6kOreghsOooy4yY64qSBvfsiN6dRH9TvjG6lgDzzi5lnfnp3zHTPOB_4KH5M-7RL5GF-aVU2SJD_yzD_LYjF7d6tfA_OfZeFp7OmdBllEIHmRNzXgFyn7Um2E6SSY70ruBL3TuKZRSUCSoi7zEa7lJz91XzT-MqJXLWjKtK7LPDLN8hi94NVPoP89lL2xaoemt0IueBUhr46QT4t0HNJaWDP-ONS-Tzxcb3dPtvpP4udFGoU4EhfuQhRZ-kOn83HYb9q3dfv4HtrdXifj9v17kL7nkvE7UGI2mNUcWyf6nk7J_-lgtXMG0Xm8F9h9M9LBar8jGE0S0LCudSsBLTj4wUR6FbZCFR5A_OHk6QBE0mNZsGmOR1x4_gYiH8MOOGZy8bRjvVLrkKvDLmY05D0wAeYGmOGbj7ugs1EWiIY-5envjbplZg3uB4M-MLU-NWQU-52Rav0Zmrh5b4yzI4L_J9T5ys6RUajZNApLJK5XRFZnRX1CDnOtbLfde0G_6bo1TNk27On_UPLIUmY3t8Pm642yPy2SrKgjXqJaJk9ok1WRcX9ixsLs5jZGegNbNlhLrXX79P3qmIsiz7Iqln92JP8KoDzhI4Md9j76ALxzsDfNN6kUaQ4AUW1FotqF5jxLoBojXRqv74PLjKG-DcisFlUCUa4iRQwyY3UBsTj7Za-VdUxxOC3Rl7l6E1vO6rypC4gYiYodWrBKMBoF6h7yEz_3mrPn8J_x2-_dXpsBXoNgNGJgXO_wBkRW1BnmPF1tmYzrgZkx7NEHZjrnG2b28XsWguAcx23DIdDb8JFmUBV1FvFRHfGRTJsp3kt_nt6GUDHeI29Z234J5zl9CXSCqWBEwsj7F7bO8btGSuuM5lV_-PW00P6F5coE0Q1HY_2xztWwh2dtWzN-t2qUx_FkFv3ag4nM07nebpkSxz57UkWHlKZDumVtlMyesuyQxEY5cLXiDw9p2j_UfufoE570mOb7A77DYN-wcoZJZ_fdR-RY23qT12bU74fMniJ4sJFe8mEKItOWbWvBwmHZXlSHUzb8m65P6yM9fhvJCBu_cDjxzrHv-dypG9ZAKBZ_VnVv8YKVloywsV3HL1i9ifGkwf-fTeRoW_qiLcRvTOhUiIq_KLigO_YsIe6lGcXqo4l-wEvl7neGzqJaZsTbqwb8qiKi4pFBZUdygTIVvyqX33RtXxbKb7r-IK17qcB_FngPdrBj0ptAOCH4eTkOxvKPSJOWqYikGVdbtJzy_EUrW4x-R3XBiYLgJS38g9J8_fKjqjjPY2ssjtI2AUp6rPsCZI8_hJXZmxUUU6DR64hn5yBJUlK8WrWy9sGOGRcA_uJpS5aUUflFj8ovXrMKcE__DZhMWDUqX-P7He_BAJYWM9xKdYftpr8T5Dbw_I4I1gqvtah16_Pn8T2FvuNcmzUiy38jsryqeNak__U1Gxbu_2fJB6hBwP3n6_6qj-LQ35v4xix-1J3xSlfrcCuBM-WbsGN34CFqfYfo8kxcUFHRip3BRVpMSUGmRZmebS5onpQFyxrCSAm8yasMaEKnlE4LURQpPZMXJCE0SROSkKxM0vOyakrOpgWhecGLpkRZAlsm23Pva56Xs3C54iKvpmV61rIaWhtuchGi4Ft_6QoRgvLFmbkI1zLqbm1RlrTSOvtExUnXwoUX1dKL7g0umWDWODCnLn6ddaa9-PuXSgLr_xsAAP__nvLVZg">