<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/149371>149371</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang Assertion `StackTop == (unsigned)llvm::popcount(Mask) && "Live count mismatch"' failed.
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          bi6c
      </td>
    </tr>
</table>

<pre>
    Compiler Explorer: https://godbolt.org/z/oYcY9fdqj
- generated by fuzzer

```console
error: example.c:22:3: fixed input regs must be last on the x87 stack
error: example.c:22:3: implicitly popped regs must be last on the x87 stack
error: example.c:22:3: fixed input regs must be last on the x87 stack
error: example.c:22:3: implicitly popped regs must be last on the x87 stack
error: example.c:22:3: fixed input regs must be last on the x87 stack
error: example.c:22:3: implicitly popped regs must be last on the x87 stack
clang: /root/llvm-project/llvm/lib/Target/X86/X86FloatingPoint.cpp:992: void {anonymous}::FPS::adjustLiveRegs(unsigned int, llvm::MachineBasicBlock::iterator): Assertion `StackTop == (unsigned)llvm::popcount(Mask) && "Live count mismatch"' 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 -fno-verbose-asm -c --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -O2 <source>
1.      <eof> parser at end of file
2.      Code generation
3.      Running pass 'Function Pass Manager' on module '<source>'.
4.      Running pass 'X86 FP Stackifier' on function '@main'
 #0 0x0000000003fbcfa8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3fbcfa8)
 #1 0x0000000003fba3d4 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3fba3d4)
 #2 0x0000000003efeba8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007ff36c442520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007ff36c4969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x00007ff36c442476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x00007ff36c4287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x00007ff36c42871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x00007ff36c439e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x00000000029c1d5e (anonymous namespace)::FPS::adjustLiveRegs(unsigned int, llvm::MachineInstrBundleIterator<llvm::MachineInstr, false>) X86FloatingPoint.cpp:0:0
#10 0x00000000029c28c6 (anonymous namespace)::FPS::handleSpecialFP(llvm::MachineInstrBundleIterator<llvm::MachineInstr, false>&) X86FloatingPoint.cpp:0:0
#11 0x00000000029c4d47 (anonymous namespace)::FPS::processBasicBlock(llvm::MachineFunction&, llvm::MachineBasicBlock&) (.isra.0) X86FloatingPoint.cpp:0:0
#12 0x00000000029c7457 (anonymous namespace)::FPS::runOnMachineFunction(llvm::MachineFunction&) (.part.0) X86FloatingPoint.cpp:0:0
#13 0x00000000032c2873 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
#14 0x00000000038eb15f llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x38eb15f)
#15 0x00000000038eb511 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x38eb511)
#16 0x00000000038ebd81 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x38ebd81)
#17 0x0000000004271c91 clang::emitBackendOutput(clang::CompilerInstance&, clang::CodeGenOptions&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>, clang::BackendConsumer*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4271c91)
#18 0x000000000496df03 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x496df03)
#19 0x00000000066638dc clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x66638dc)
#20 0x000000000496e308 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x496e308)
#21 0x0000000004c61c75 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4c61c75)
#22 0x0000000004bde97e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4bde97e)
#23 0x0000000004d55741 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4d55741)
#24 0x0000000000d9e07f cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xd9e07f)
#25 0x0000000000d94c5a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#26 0x00000000049d59c9 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
#27 0x0000000003eff044 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3eff044)
#28 0x00000000049d5fdf 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
#29 0x0000000004997eed clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4997eed)
#30 0x0000000004998f7e 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+0x4998f7e)
#31 0x00000000049a1bc5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x49a1bc5)
#32 0x0000000000d9a52f clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xd9a52f)
#33 0x0000000000c4ea64 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xc4ea64)
#34 0x00007ff36c429d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#35 0x00007ff36c429e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#36 0x0000000000d94705 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xd94705)
clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
```
Code:
```c

static __inline double mypow(double __x, double __y) {
  register double __value, __exponent;
  long __p = (long)__y;
  if (__y == (double)__p) {
    double __r = 1.0;
    if (__p == 0)
      return 1.0;
    if (__p < 0) {
 __p = -__p;
      __x = 1.0 / __x;
    }
    while (1) {
      if (__p & 1)
        __r *= __x;
      __p >>= 1;
      if (__p == 0)
 return __r;
      __x *= __x;
    }
  }
  __asm __volatile__("fmul %%st(1),%%st\n\t" /* y * log2(x) */
                     "fst %%st(1)\n\t"
                     "frndint\n\t" /* int(y * log2(x)) */
                     "fxch  %%st(1)\n\t"
                     "fsub %%st(1),%%st\n\t" /* fract(y * log2(x)) */
 "f2xm1\n\t" /* 2^(fract(y * log2(x))) - 1 */
                     : "=t"(__value), "=u"(__exponent)
                     : "R0"(__x), "1"(__y));
  __value += 1.0;
  __asm __volatile__("fscale" : "=t"(__value) : "0"(__value), "u"(__exponent));
  return __value;
}

const double E1 = 2.71828182845904523536028747135;

double fact(double x) {
  double corr;
  corr = 1.0;
  return corr * mypow(x / E1, x);
}

int main() {
  double y, z;

  y = fact(46.2);
  z = mypow(46.2 / E1, 46.2);

  return 0;
}
```
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJzsWsty2zjWfhp4g5KKBO8LL2jZ-v90dSquODPVvWKBICihTQJsALSlPP0UQFK8WHbsjqZnMeOKYwmX73zn4Nx4wUqxHaf0GgQ3ILi9wq3eC3mds5Bc5aI4Xm9E3bCKSnh3aCohqQReCvdaNwp4KUBbgLY7UeSi0mshdwBtvwO0Fb-T35Oy-PMP4KQruKOcSqxpAfMjLNvv36kETmr-hU73jwiuREWBk1IphRVBD7huKromwEsRAl7qmdGSHWgBGW9aDSXdKVi3SsOcwgorDQWHek_hIY6g0pg8_hiP1U3FCNPVETaiaWhxEdT_sfwAS1JhvjP7AdpKITRA26p6qleNFH9QMnw1f1gO0PYbljtqRn-Lw-7_bSWwZnx3LxjXa9I0wEuTxNCCT4IVEEQ3mAt-rEWrQHRr3NZLt_cP3Qdc_NEq_St7ol_pTgEUt9xGhLGMBmgDrXS79DMme8bpDVaM3FSCPHbDTBvvFhKgxMhMlaJSM8EhCJ0Ho-Q30UDg3QLvFk7wAUpG6EY0RLRGYPwZq0eAEghQCFAIAUKGHLTTsGaqxprsAUIARbDErKLFGjjp_a936cMdVG1eMw0xzNsdlLQRUkMtlvHK9L7N10TUE-POTc6UaqkCaAsxN5YgVVtQe3REYrWHOSaPWmJCjYUaSRspCFWKFlCJVnbDZidWShBmY1-2HCoiWaMNX2sYWLS1OS3gpM4aOMm9FDuJa4jlrq0p16p3C9EYTqTPRCs6ZCK0tc6zwoPJ1UrLlj8CtM0ZH6bhalc8Y1mufLjawZUwiLhpDG6rm1avFVyVXKyeqMyFoiusargicLXaEbLSQlRkjxk3B_gWE7NYcdyovdBwVRJRCbkqGN5xoTQjvQxrvfnwFwSBt-nN5t0BJ3WNLYC3oaIE3h1ssFRUQqwh5QUUJSyZTZXILNuIgg4JlgkOnNQzw19bzhnfwQYrBQGKti0n1ifvzcBnzPHOsI5MQNaiaCtqVs14oMick38O7bc4hNt7aM-QleyEVA5SDJbv1MZsKAKOOUTPgc7BGX68MicljifBpY6q-3AvGddd3HQOFo-LJH7OhNKS4tqGx6YLUhMs8U_7CUA3zqEnZmK5o-0uaGOv8M_R3lQU87b5wh_YjuNqmkgqYcAvS9LQGEmiGUla0hzHcGN87Ssl4onKY8fq_zEvKiMr7u02W7MRXNPDkEId-9vhez1-VJZeSHwfBcjp1emy8iEOs9BfVYy3h9WOt90EWSuxDi1lu2Uk7M8BkzApCWz0XlJcZI-sqj6GbveP6MGSrh-FcKesCT5K24_CETicA6M4Kj2Ic5NlPwRrN46w0QtYN_8woJuPgPEc0EtoEn4M0G4ZAZOpg6GEuEVgMkZ8KqyQ45qqxgZs8tMl9hNXWt60xlk_DdXV25xfZgBKXKkuaSXwlY5gcGcT0s5CGxST8N3a7G0MPTSUMFxt72f56afph-_UwF1o4Bd-9G4N-mI96WPO6DBUjD7PvtUFdawBitdMSbx23qkDWugQ-cH7dZAt_8JfUP2BGh3JBkv9bpLeLLMiguLIe2mMQYqprhN-Z4m9yegM3hlS_oxUTHM3KCektvdm31DkP0znQjWqo9WlEEM6WJIOXPcdpD_b7mR-tP3Q5QkHrjsSDpeEi3hKuKI7TI59zzJS_1Q31Yn-30S7iCe0oyltH0UuSVw4XGQBL6U10zeYPFJefLH9L0DxZHq43jfJCXNC-_ifrSjo_1H-pbHEXuSHBy0Z332l5SJt9NqnC7SeSto74XTLJ65lq2zZKDdc3-t5Fn0q-1jbsoo-HJWmtc2hG6h00c20nP3Z0qxZ7DRtZPMsmabZ0ExONhW0xG2ls4JWVNMfbPTuepkvVdoIrtranGZ60RPvz3Q88Xh24klYlI73Fh872LWC3yTmqrKXDv_gbOEK6cO3viW8tNP2JEcVZv1FGIZeXJCpCvfmGih9-DYn-EBr3PtfLkQ1_r0g1Z7MiSpyFtamnhOfCY_eoe3Q3YGSVtPBx-NL29JQGAnOegOfhC6JginBrTSHegq5KcOLc-ukj9xmNd_PC5pEFL6Vfc7a73VlLu2nHcOR_6wd8IsgiPxZcu2Zjmo8CYJfsn6ZZC-cIjpmI-9Zx-AUCXWiEhLiZt01-qRKpVLio8ne3obssYREcKUNvz7NzcbQxt5iuzT9jt_IPliw90mA4WDqjfvNxvxEh4caV9U_KdGiL8dnVFlULYPRJ7thnXWlQrInKl_2YCicp4EiSEjS3W8cQYf7IZm09uzuRtoQs3XDLCG4qnJMHrOSG5qji3SCe3fZuBtR15gXy2g9e26nSiZsicbVrIaN9flUu04bsowcDq7bfclNh2_qHDOcrAlni81ApiVmWg3TCzhcVcb97dXPMG-WpGOmto7TGdxuASiqcJ0XGKBoNBWKh3sov4j8zGFEi_sfpeNPb9Kcu8vRzXxt-QMuaXWc2fLtc7to99ZxHV09XrpVWZTwv9ktFhdI588_mVstiSgtXrWaPS_8ovYNppwl6sVGs2CSHjZvyJguTWdNykSxS3UAVuGTE3mLFiWJy3mVfY85fhG5et0Wv4j8V6b0zBZv5d_T2TeYmWPvb_y813y9g_ybjWjMNBpx3kYl2M1J8Brh28nnWQtwpva_Zvy_0YgX7T6tYUazoUWtxgHqE9jQawy0beJI-7D_cSW-YHdhOI2MZz2dQ3yKQx8arpcT2YGOIhe3v1FSJB-8n263jIDBEpD6DswysydTGkudTRR6twjqT0SEyyYscgLYgV_ybAxsJ_T0YPj03Ll7nFf2LT8kvYd3T0HhM9N7SA_MuE1Boev59nGronD1BLWAilLIJg25kXF6u0FS3UpOTYCZndOXE-yygnbPKcdXFrpXGJTGmhGYZYxXjFNYiDavKKyPjXgGKO6_ZtnBOPnp29E6dHQDnBRCSXdMaSrH6SdctfYRapbRQyM45Rp43WLTB8Essw-U4dgXGch-BSvNeJYdJ8-cO2S7rpmKhqNMaRHdtTPgjEinp9fDAxz701ns9R0bu3wQNVBeGQan9dBYZhAMAdpaS52mQXTbf3reM_uI0t7omtCfiUQhdKcMYaeWSX23c2DY87EZ0UifTr2qdq9xlskXGpyRMZAf_mYZVrU5XGESfkWzzEYNKuu2ggAFAAUm13W38tDmNBJsOAg2GiAE7eP7FB6NPFiJHQIoPnS50T7aHxWf_RghtlTOZYzAb22UvDAJ-yULm8bjF1zeR-dA9vAvElJt_jFzlRKTd1A12OhQu2cQEAjMNchbQAZrBd0fqW7fZ0DAu7VaGi_rY93o0E-1w9Qp9mc-fQ7wqzPsOYxQ7jB27Cn2rtnLhADdLEL-VRdVBJv0gd5SYJhzXtHsrFojq1NwddvsaBc6phTYXq_PVXeuzRhoHbkxis2vHySOHyAv8EIHxZEfuV7QIzhpv6vszq7_dpimkX6MCHkKbPN5mRB7ht0USk85_mAT151r9DycNDpxZ1zDvvM5I_Rodn0_kYXQpu2BrR-u0cRG3-3cINdMTkTP1k4JOzNCQ_26Kq69IvESfEWv3ShAURT4yL_aX-PQjVDg4tDzwqAo4jguSeSjxKGOg4mXX7Fr5KDAidzIjR3P99e-W7jED_2YYhxiTIHv0Bqzam2aurWQuyv7OtG16yde5F5VOKeVsi8cItSXfgSC2yt5bd9CytudAr5TMaXVCKGZruh11wH8B16xumpldf3XX6PqVX-6Rv8KAAD__yCZb8c">