<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/118223>118223</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [llvm][Mips] After 677177bb60d, Assertion failed: (!NodePtr->isKnownSentinel()), function operator*
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            backend:MIPS,
            llvm:codegen
      </td>
    </tr>

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

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

<pre>
    After `llvmorg-20-init-06683-g`677177bb60d ("[Mips] Fix mfhi/mflo hazard miscompilation about div and mult (#91449)") by @yingopq, building parts of libzfs on FreeBSD for mips asserts with:

```text
Assertion failed: (!NodePtr->isKnownSentinel()), function operator*, file /home/dim/src/llvm/llvm-project/llvm/include/llvm/ADT/ilist_iterator.h, line 168.
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: /home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang -cc1 -triple mips-unknown-freebsd13.4 -S -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -mrelocation-model static -mframe-pointer=all -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu mips2 -target-feature -noabicalls -target-feature +soft-float -target-abi o32 -msoft-float -mfloat-abi soft -mllvm -mips-ssection-threshold=0 -mllvm -enable-shrink-wrap-region-split=false -O2 -Werror -Wall -std=iso9899:1999 -ferror-limit 19 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -faddrsig arc-cacfd2.i
1.      <eof> parser at end of file
2.      Code generation
3.      Running pass 'Function Pass Manager' on module 'arc-cacfd2.c'.
4.      Running pass 'Mips Branch Expansion Pass' on function '@arc_init'
 #0 0x000000000469d6d8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x469d6d8)
 #1 0x000000000469b4b9 llvm::sys::RunSignalHandlers() (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x469b4b9)
 #2 0x000000000469de9e SignalHandler(int) Signals.cpp:0:0
 #3 0x000000082a71057c handle_signal /usr/src/lib/libthr/thread/thr_sig.c:0:3
 #4 0x000000082a70fb4b thr_sighandler /usr/src/lib/libthr/thread/thr_sig.c:244:1
 #5 0x00000008293402d3 ([vdso]+0x2d3)
 #6 0x000000082e8d45ca __sys_thr_kill /usr/obj/usr/src/amd64.amd64/lib/libsys/thr_kill.S:4:0
 #7 0x000000082e61d0b4 __raise /usr/src/lib/libc/gen/raise.c:0:10
 #8 0x000000082e6d14f9 abort /usr/src/lib/libc/stdlib/abort.c:67:17
 #9 0x000000082e600871 (/lib/libc.so.7+0x9c871)
#10 0x0000000003045032 (anonymous namespace)::MipsBranchExpansion::handleMFLO() MipsBranchExpansion.cpp:0:0
#11 0x0000000003043565 (anonymous namespace)::MipsBranchExpansion::runOnMachineFunction(llvm::MachineFunction&) MipsBranchExpansion.cpp:0:0
#12 0x0000000003bc9cee llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x3bc9cee)
#13 0x0000000004181a50 llvm::FPPassManager::runOnFunction(llvm::Function&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x4181a50)
#14 0x0000000004189ed4 llvm::FPPassManager::runOnModule(llvm::Module&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x4189ed4)
#15 0x0000000004182552 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x4182552)
#16 0x0000000004e92f2f clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, std::__1::unique_ptr<llvm::raw_pwrite_stream, std::__1::default_delete<llvm::raw_pwrite_stream>>, clang::BackendConsumer*) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x4e92f2f)
#17 0x0000000004eb790d clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x4eb790d)
#18 0x000000000636b569 clang::ParseAST(clang::Sema&, bool, bool) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x636b569)
#19 0x00000000052edc93 clang::FrontendAction::Execute() (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x52edc93)
#20 0x0000000005279e3d clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x5279e3d)
#21 0x00000000053cdefe clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x53cdefe)
#22 0x00000000029e8d64 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x29e8d64)
#23 0x00000000029e58d5 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#24 0x00000000029e4b82 clang_main(int, char**, llvm::ToolContext const&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x29e4b82)
Abort trap
```

Minimized test case:

```c
// clang -cc1 -triple mips-- -S -target-cpu mips2 -O1 arc-min-2.c
int l2arc_feed_secs, l2arc_feed_min_ms, l2arc_write_interval_wrote, l2arc_write_interval_next;
void l2arc_write_interval() {
  int interval;
  if (l2arc_write_interval_wrote)
    interval = l2arc_feed_min_ms / l2arc_feed_secs;
  l2arc_write_interval_next = interval;
}
```

See also #118215.

</pre>
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