<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/121289>121289</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [Flang][OpenMP] CodeGen/RegAllocFast.cpp:696: void (anonymous n[Flang][OpenMP] Assertion `(&MBB != &MBB.getParent()->front() || IgnoreMissingDefs) && "no reload in start block. Missing vreg def?"' failed.
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            flang
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          k-arrows
      </td>
    </tr>
</table>

<pre>
    Reproducer:
```f90
integer :: x
!$omp parallel private (x)
!$omp task shared (x) depend(out: x)
!$omp end task
!$omp end parallel
end
```

Stack dump:
```console
 #0 0x00007f6a73a167d7 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int)
 #1 0x00007f6a73a1436e llvm::sys::RunSignalHandlers()
 #2 0x00007f6a73a16eaa SignalHandler(int) Signals.cpp:0:0
 #3 0x00007f6a73347520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007f6a7339b9fc __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
 #5 0x00007f6a7339b9fc __pthread_kill_internal ./nptl/pthread_kill.c:78:10
 #6 0x00007f6a7339b9fc pthread_kill ./nptl/pthread_kill.c:89:10
 #7 0x00007f6a73347476 gsignal ./signal/../sysdeps/posix/raise.c:27:6
 #8 0x00007f6a7332d7f3 abort ./stdlib/abort.c:81:7
 #9 0x00007f6a7332d71b _nl_load_domain ./intl/loadmsgcat.c:1177:9
#10 0x00007f6a7333ee96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
#11 0x00007f6a724b86ac (anonymous namespace)::RegAllocFastImpl::runOnMachineFunction(llvm::MachineFunction&) RegAllocFast.cpp:0:0
#12 0x00007f6a724c4a3a (anonymous namespace)::RegAllocFast::runOnMachineFunction(llvm::MachineFunction&) RegAllocFast.cpp:0:0
#13 0x00007f6a722d40c4 llvm::MachineFunctionPass::runOnFunction(llvm::Function&)
#14 0x00007f6a70c6196b llvm::FPPassManager::runOnFunction(llvm::Function&) 
#15 0x00007f6a70c698a1 llvm::FPPassManager::runOnModule(llvm::Module&) 
#16 0x00007f6a70c6237f llvm::legacy::PassManagerImpl::run(llvm::Module&) 
#17 0x00007f6a747f4b49 Fortran::frontend::CodeGenAction::executeAction() 
#18 0x00007f6a747e91ac Fortran::frontend::FrontendAction::execute() 
#19 0x00007f6a747cf0e2 Fortran::frontend::CompilerInstance::executeAction(Fortran::frontend::FrontendAction&) 
#20 0x00007f6a7496737c Fortran::frontend::executeCompilerInvocation(Fortran::frontend::CompilerInstance*) 
#21 0x0000558a1e9d3433 fc1_main(llvm::ArrayRef<char const*>, char const*) 
#22 0x0000558a1e9d197a main 
#23 0x00007f6a7332ed90 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:58:16
#24 0x00007f6a7332ee40 call_init ./csu/../csu/libc-start.c:128:20
#25 0x00007f6a7332ee40 __libc_start_main ./csu/../csu/libc-start.c:379:5
#26 0x0000558a1e9d1495 _start 
flang-20: error: unable to execute command: Aborted (core dumped)
flang-20: error: flang frontend command failed due to signal (use -v to see invocation)
flang version 20.0.0git (https://github.com/llvm/llvm-project.git cb1ad985b53c87b53974e37bba60129acb294f0d)
Target: x86_64-unknown-linux-gnu
Thread model: posix
```
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJy0V81ypLjSfRrVRmFCSPxpUQtsT31fLxzj6Ol9hZASimshEZJw229_Q0CNi3KNp3txI-woENI5mUnmyUR433cGYI_ye5Q_7sQUTtbtX-6Ec_an3zVWve-_w-ismiQ4xGpEalSQ5a_lBJG6NwE6cDg-ZDV-iztoimhmhxGPwgmtQePR9a8iAEa0ekOUbzYF4V-wPwkH6vwcKxjBKEQrO4UF9uoQGDUf_LR4pkSkjggX9sZrUv8VhHzBahrGK3ekNd5qQKTGiDKCyRshhJRtIUom0qJUJdb6dVj89O9-uXh2vQkz5g8nJCBafWxy4ufR-uBADIgWiD7g3oTFkUiRXlFkrIBbFN8n81ffGaH_XxilwXlEqw8Uem0oCIE3-xGtFt512SdyjM6T-X9BYRsUlpU5JXjmOei-QfTwVhXHIrvTvZne7jozLQ9k4m1SIHpP3jKaU_JhVrYF5A1vJT4ex3ByINTxpdf62A-jhgFMEKG3BieIHswYNKKHy22JRKzOMsTqsljB818BNwGcEfpL2LJCrE7PQShuwV6e-RKr4pdY5XVAs7LAnZ9fwAyzXCJ6SOa7d69g9BHX-v4N0YMTvYcZmJaI1WfXqy0uVWXLsGisCwtqUMv7mpcWu9Lo6HqcfzqeNvho9FFboY7KDqJfXkRvZi_j8uA7KRasNC2jMUspsnRbJIwB8OL3soZx4MW5tlm6KQmaNVUhZAQUxpr3wU4eGzGAH-dK42t5QFdrbeVB-PBtGPVae5P50zwJeeoNHCYjY4ZtivPTs2gGvgS7KpNoH93aJzPBxO_Y97-0bVPClKqMyAz_I-az8P7CmptmbPlXmk1hE1mkvGguaA7PEflJGNEtDePXCfDKkF8x8Eqkv8DwZNWktwJ8XrpEL67QKSvbC3QNnZDvq7Z_8GwS6185NsWflW3WZBwfrAtOmOVU66wJsT_Ndw9Wwf-BqZdgzEvwBnIKUJ-DdoFebdGBp0J-hX5Y727Ab4H5Fli2BOjXZg9jr8F9Mz4II-G25b9u2WUM6UZbMl6UrPzSy5X2w6ZXK8W_m_DJB1pfGHHWozyvRApcsYwx3Mr0GHVykwa1c-L9O7SIPciTcDhOEyGCsT9i49-ufRDQK4KUlwLPIrxuuGrMFBQn-HiMKnr0QbhwlELr49-6Lf30uaesLevWoeSEWJ3PbbBYKbNrSsgIng_0pg_XLMtlhL6boZc-QSMiXaWJ5rcQN07csv8mMiujrOYrcHEdvozneIGMAWy1MN0djSqJwTkb5QJPRjQacLB4TRks7TCIOSFwHdvmModK62CeE0Et6ncTbV7E55w6Q-FW9BoUVtNMtLZ9RKvJA757ndcAcH-RpH8z4FdwPs5DlCQkIV0f4sFTCOMs2PSA6KHrw2lqEmmHGKGYhMvP3ejsf0CGJJ6STSoUr_ImZ7Iqm5zxMgNWNo0oSEq5kA3lWUtW734I18Eyay9NezIvxv40F82b1D_mmQcPVkGUQ7wMKxdD9E7tmeKMix3s05LlWUkKku1O-zIHTngreAFS5i1vWg5QkYI2lWCpoLt-TwnNUkp5mqaEZIniTPGyyZUikvBGoYzAIHqdREcT67pd7_0E-5SmtOI7LRrQfv6SoXQOJKI0ftS4_RyZZuo8yojuffAfEKEPev78Ocwn8keU3_85gnl6RvkjXnUZ0cON3lvwIobg1fbqagT4J7jae3DzqBuDFaW3eLq_x_H7hT3i5S7pIDwLB3Fgj9p8h9gfc3adpbp8QOUD_tYZ6-Cp97433SO0fn4WBTQOYNRY7CDObrg3eCmHRlv5kuD1CH510GEV9eoQ40TLNWWT3eT0_veyLY6L8VVEqVnfxuue_jcAAP__6pVNIw">