<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/105747>105747</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            `SelectionDAGLegalize` crash with assertions on `powi.f16`/`powi.f16.i32`
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          tgross35
      </td>
    </tr>
</table>

<pre>
    Source code:

```llvm
target triple = "x86_64-unknown-linux-gnu"

define half @test_half_powi(half %self, i32 %n) {
start:
  %v = call half @llvm.powi.f16.i32(half %self, i32 %n)
  ret half %v
}
```

Crash (assertions required):

```text
llc: /root/llvm-project/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:4708: void {anonymous}::SelectionDAGLegalize::ConvertNodeToLibcall(llvm::SDNode*): Assertion `LC != RTLIB::UNKNOWN_LIBCALL && "Unexpected fpowi."' failed.
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/llc -o /app/output.s -x86-asm-syntax=intel <source>
1.      Running pass 'Function Pass Manager' on module '<source>'.
2.      Running pass 'X86 DAG->DAG Instruction Selection' on function '@test_half_powi'
 #0 0x0000000003ae7028 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/llc+0x3ae7028)
 #1 0x0000000003ae479c SignalHandler(int) Signals.cpp:0:0
 #2 0x00007b9927e42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #3 0x00007b9927e969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #4 0x00007b9927e42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #5 0x00007b9927e287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #6 0x00007b9927e2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #7 0x00007b9927e39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #8 0x000000000376d745 (anonymous namespace)::SelectionDAGLegalize::ConvertNodeToLibcall(llvm::SDNode*) LegalizeDAG.cpp:0:0
 #9 0x000000000377f1a6 (anonymous namespace)::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*) (.part.0) LegalizeDAG.cpp:0:0
#10 0x0000000003782883 llvm::SelectionDAG::Legalize() (/opt/compiler-explorer/clang-assertions-trunk/bin/llc+0x3782883)
#11 0x0000000003899fb7 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/opt/compiler-explorer/clang-assertions-trunk/bin/llc+0x3899fb7)
#12 0x000000000389d1fa llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/llc+0x389d1fa)
#13 0x000000000389e550 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/llc+0x389e550)
#14 0x000000000388f3ef llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/llc+0x388f3ef)
#15 0x0000000002a848e9 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
#16 0x0000000003073ded llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/compiler-explorer/clang-assertions-trunk/bin/llc+0x3073ded)
#17 0x0000000003074181 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/compiler-explorer/clang-assertions-trunk/bin/llc+0x3074181)
#18 0x000000000307347c llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/compiler-explorer/clang-assertions-trunk/bin/llc+0x307347c)
#19 0x000000000084693c compileModule(char**, llvm::LLVMContext&) llc.cpp:0:0
#20 0x0000000000737a66 main (/opt/compiler-explorer/clang-assertions-trunk/bin/llc+0x737a66)
#21 0x00007b9927e29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#22 0x00007b9927e29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#23 0x000000000083d92e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/llc+0x83d92e)
Program terminated with signal: SIGSEGV
Compiler returned: 139
```

Link: https://llvm.godbolt.org/z/zhb1bxWK8
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzMmFtz4ygWxz8NfqHsQiDr8uAHx46zqXFfatIzs28uJGGZDQItoMSZT78Fkh3hpLsns66t7ep0R0j8z-8cDocLNYbXkrEFmN-A-XpCO3tQemFrrYwh80mhqpfFg-p0yWCpKgbIEqA1QKd_E9T_FeKp6Zss1TWz0GreCgYBWUOA8TFLdkk87eSjVM9yKrjsjtNadgDjsVzF9lwyeKBiD0GMLDN25x52rXrmAGf9Czw3TOwBXkFOsHuUAOcQpDe9iLFU2zMndB88eY6SCnHWdsAzJzvbR8mME_xj-ZOYZhaePnsa0NP1RTDGLq00NQcIcEaNYdpyJQ3U7N8d16xyut-Jp2VH2zcJUQKyhABvtFIW4I0jn7Za_YuVp0f3Hy8A3qxUxe6YBHjzwAQrnbn18g7gzZbVVPA_2Xp5NyvbFpBlnKLMCT8pXrngUankS6M64_whS0CWY4lT__7NSsknpu1nVbFvassLF1mAM4_Sd127dwAvexfh8uQ8BAnariDAkRuRX79t72_6Hr99_uXzlz8-77b3N6vldgsBTgBOXO78JtmxZaVlFdz7AXNJg1O4p1ywatZH6ev2dvlwC01XNNxCCouuhpq1SltoFTxY2xpnB28A3tTcHrpiVqpmFL4wqNyYjhmAN5DKCnJZiq5i0B4YLP14FrR8tJqWbDD_YGn5CKuuac8DimYA5V-1qjVtINV11zBpzTCUqnVWStW0XDA9ZcdWKM20axNU1tPXZJla3clHgDcFl56zhFPlJGjbOqHOtp2dGTg9ZsmUmmZqXqSlR0DWXFomICAr46cvILc9WOTAfu2k5LKGLTUGApxuOumHGn51DZ-opLXDSaGSsFFV56YyTgMxnA7O4_cE_5klcL28mwJyu17ewXtprO56E-e8GvT3J9vOwttZnw5zD2CCIDqi0x9CWYpwBl-zzryY_pevmkvrx-SbG6QgNTV93iljNaONz7EV5NL6AoKz_3JkAL5BxwHrtWYATKIL7jjNS_jAa0nFP6ishNPPBoy-2QyzFPmfsxAehNIiz3HKYjzHaADvC8BQaEcF1r0oZ0bNEo_nuwRwJNTMk3xfwtYeNKPV7pEL8TEDvn9gIL6EjtME1sb7-VH4OE0C7XmojbN0TyAt3Lz_kLLvGCgnb5Sj4sOaURFopqEmyVmefEzTdwk0syC30qRK47lfb071HEraMNP6eZBftbLDt6vKRb7mIVy6j2jy9-FOT1_a7yMBnM1aqu0M_RTQTcywoqQZzjIyqijBKhow-FG7XtHoLZ8H1qGFRSPL832Rfgft_oGJ0_j5DcBSVrcNt37tvypnjxFw4gvOKtrTn3L2rUshbqjh5Y1Q5aMJBvW8IJVKGusr9TW9cJCBF-TCCzafo596oTv5RX6i5YFLdgIOvHjz7spuOMrAjTh0I9sTtv-BGy6by5f_D2c8a-DMfOwMplmcsRx-l8ftXEaevOvCW_ZRsXhH7_2ikQRBRimpWDXi2nx1XU97qA8TXSWaPVQQzfSCOo6y6C9Qf_K7vzARhqYrEzuggDi7jHOcliNiMUreEft9075Oz_8Ft8MKuINVD2VxkpMSDjbO4SwPVPs1a-n2oK-Q2-3vn1ZK-gNgTypE-W4e4mDxQilJaZLAhnJ5Led6ybFvOLrYFuVV_sEdqO8SaOJLTRYjuNu5bjt_mt-NnPrLVlgcWiHhqJAqxwz2-teKVy96tno6_VmmGy6pO8E-c3uA_dbXHQUf7u8ebu9-H64KBsNQM9tpySr3RUTyH9wubLl8dF-FB1x_t1GrqlDCzpSuAd786X4ORVQc__glm1QLUuUkpxO2iFIckyTLMJocFmmURDHaszku0wwXhMQoQXlZZXnB5kWxn_AFRjhGGcYu_TCaRfM0xlnJipiW2T4mIEasoVzMPIPS9cQfpRcRmqdxOhG0YML4yyaMJXuG_q070M_XE73wp_Ciqw2IkeDGmlcZy61gC5Cgd7eHCRoO5j6-o6uW_sbhdM_jooc3owZ_8ZOgSafF4u9fEgzOPS3wfwIAAP__ERvG0g">