<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/65107>65107</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            LLVM ERROR: Instruction Combining did not reach a fixpoint after 1 iterations
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            llvm:crash,
            llvm:instcombine
      </td>
    </tr>

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

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

<pre>
    ```llvm
define i1 @f(i16 %0) {
  br label %BB1

BB1: ; preds = %BB1, %BB
  %C = icmp ult i16 256, %0
  br i1 true, label %BB1, label %BB2

BB2: ; preds = %BB1
  ret i1 %C
}
```

https://godbolt.org/z/h7o9sbEKP

```
LLVM ERROR: Instruction Combining did not reach a fixpoint after 1 iterations
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 instcombine <source>
 #0 0x00000000034a5a58 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x34a5a58)
 #1 0x00000000034a318c SignalHandler(int) Signals.cpp:0:0
 #2 0x00007f8a50d47420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #3 0x00007f8a5080a00b raise (/lib/x86_64-linux-gnu/libc.so.6+0x4300b)
 #4 0x00007f8a507e9859 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22859)
 #5 0x00000000007834af (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x7834af)
 #6 0x000000000300c8d8 combineInstructionsOverFunction(llvm::Function&, llvm::InstructionWorklist&, llvm::AAResults*, llvm::AssumptionCache&, llvm::TargetLibraryInfo&, llvm::TargetTransformInfo&, llvm::DominatorTree&, llvm::OptimizationRemarkEmitter&, llvm::BlockFrequencyInfo*, llvm::ProfileSummaryInfo*, unsigned int, bool, llvm::LoopInfo*) InstructionCombining.cpp:0:0
 #7 0x000000000300cf4a llvm::InstCombinePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x300cf4a)
 #8 0x00000000036ba32e llvm::detail::PassModel<llvm::Function, llvm::InstCombinePass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x36ba32e)
 #9 0x0000000000d3fd8d 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/opt+0xd3fd8d)
#10 0x0000000002e0ebde llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x2e0ebde)
#11 0x0000000000d247de 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/opt+0xd247de)
#12 0x0000000002e0cbdc llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x2e0cbdc)
#13 0x000000000088448a llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::PassPlugin>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x88448a)
#14 0x000000000078e621 main (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x78e621)
#15 0x00007f8a507eb083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#16 0x000000000087980e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x87980e)
Program terminated with signal: SIGSEGV
Compiler returned: 139
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzkWN1y4yoSfhp8Q9mFQL8XvnCc-OzUSWpScWr20oVES2YjgRbQnOQ8_ZaQnFiOczYz44v9mfLEFnR_3f11g6C5tbJSAEsUXaHoesY7t9dmWexLbt0s1-JliWIyfOr6e4PINSIrAaVUgGWAUUhKRFMZxBjRiCCaYZRcDVIY5wbXPIe6n7u6Cobh4W__yFYYsSvcGhAWI3Z9EKPr4dcBBtFo7edl0bS4qx3u7dEoHiXJkT0ZYGc66GcmpqfPdOoK_dCVEdiA89HSaD1qJtfjjwM7x4h751qL2ArRDaKbSotc126hTYXo5k9EN_tEZza_-f3-WOkE6fb22x2-eXj4-tA790VZZ7rCSa3wWje5VFJVWEiBlXbYAC_2mONSPrdaKod56cDgAEsHhvdKdgC9v71ZbW-w7fJGOsxx3lXYQKuNw07jE7el23f5otANohuf--Fr3hr9DygcohtpbQcW0Q3mSmCpiroTgN0ecGG43eOcF0_O8AIWg_mt48UTFl3T9lb8EFkgkt0bXRneYG6qrgHlrM8H3ei2t1LoppU1mDk8t7U2YPqxmqtqzq0F48ObO9OpJ0Q3uVSDIp7rHoK3bf_cubZzC4vnWzxvezWLpbKu8FQCRmxtdWcKQOxmzDmijGDyTA7_WMgjHqXYM8FWiK3six1-3BupnI_tsQ8W0fRNyPA_dto6A7xB1BesVM4vE5r-YoSIXpHn0S1Esze_gxO_WZAWeCsrxeu_cSXqHj8d3RiG7aJo-5wQ__8ViI5ASZnyiIgwCSnBu50B67SBnXFjFLXMEd08p_EuDue1VN3zvFLdMNG6vQEuFlYviPc4CENKJv6yiZmUcEJybLi08An8okeOPXLICMknyOEEOYEsjTLMc_0pz4-QKU2jbIIcHXNMkpSFvLxUTge0ibl4klJCilSkeKzeo73Bfv0OZtMp_zCpw7dBX4RvE0faf9fmqZbWvZNZrR7AdrWziK5OZqztmrZXXvNiD-80H7mpwN3K3HDz8kWV-gOJR8OVLbVpzspc60Yq7rR5NPDextfWyUb-6fe5B2i4ebpppHM94yeSV7UunjYG_tmBKkZ3TgK6N7qUNWy7pnn12It0yr8pxbB-1zjXup6q3mrdvipkx1v26459fpklp8ktQ36SoQEB7rkd9xzTfTK_K8XrFyvtHVe8AoPY-owSu_F6l9uVhiAmJZxOooxzzigc-SnAcVmPSeDW3mkB9Xlv39XvMTsn2QQL5juIgQWwP8dN__kvIH3gdEJ6NtmmBCtFKi5Aupf9q9h-lub_3-wNuXlNXv8an5w_KBDIxfGKudOiq-FRH1zqk7ISvHXanA94UPihcEeVSwc7BjOJNpiWKg0T8WP7wyG89Sc5ulStvXH0UaX95xA_0DrhnZ5UWZGL4hNL_Rzb_yssjSxMaGKT8kzTMEyPX9Km87V1L1uopZreAbbOSFU9QHmuNj84EN3xYu9xVv_mQPWlaev3UlrXX_2dZyPrMyC_NP1BOCtj-Es_epwgz0ndVVK9291163auP0QNhzhv73epxF9JfQMjSwnmIHc4hP3Y98XqZKiCSZmEJ_cCiGmAGy7V5S4HPeTEZnRyy8lJyvBu119hdtZx43ZHDnz2xhOSlE2sxNMFkGQpATzgX4xPD_pq9dAWcGD8-R8E_kO6Pbb-zorYCm-__La9-e3bIL4eDWMDrjMKRC8RsOykvTITSyYylvEZLIM4YywLopDN9kuelnlO45hHPMuTnNIkjAQpRCKiJEwIzOSSEspIykhAGKVsEadRGfMkEEKEOSsiFBJouKwXff0utKlmvkOyjKOAJDPff7K-00bpWOG-T4IoRXT9NnjUmeinouuZWfrOS95VFoWkv6PZNxtOuhqWF-4XzTpTL3--IeQj_lcAAAD___CoQm0">