<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/138944>138944</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Assertion Failure: "Operand is DELETED_NODE!" exposed after llvm19 upstream commit cbb0477e9a8d
        </td>
    </tr>

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

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

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

<pre>
    We've had a compile-time crash reported to us, happening with optimization, fast-math, and FMA (`-O1 -ffast-math -mfma`), which we've bisected to llvmorg-19-init-9453-gcbb0477e9a8d.

I'm not sure if there is a problem in that commit directly, or if it's exposing a latent problem.  Specifically, in investigating, my colleague @OCHyams noticed that an older commit (llvmorg-16-init-15033-g6161a8dd5c5a) appears to be related. Reverting the change of that older commit avoids the crash.

Here is the reduced test-case, which fails in llvm19, llvm20 and trunk:

```
typedef float __m128 __attribute__((__vector_size__(16)));
typedef int __v4si __attribute__((__vector_size__(16)));
__m128 x1, x2, x3, x4;
struct Container {
  __m128 f;
};
class fVec {
public:
  Container mData;
 fVec(const __m128 &);
  fVec operator-() const;
};
void consume(fVec);
fVec::fVec(const __m128 &m) { mData.f = m; }
fVec fVec::operator-() const {
  __m128 k = -mData.f;
  return k;
}
fVec process(fVec m) {
  __m128 t1, t2, t3, t4;
  x4 = __builtin_ia32_rcpps(m.mData.f);
  x3 = __builtin_ia32_cmpneqps(x1, x2);
 t1 = m.mData.f * x4;
  t2 = x4 + x4;
  t3 = (__v4si)t1 & (__v4si)x3;
  t4 = t2 - t3;
  return t4;
}
void foo(fVec vIn) {
  fVec v1 = -vIn;
  fVec v2 = process(v1);
  consume(v2);
}
```

Compiling this with a compiler that includes llvmorg-19-init-9453-gcbb0477e9a8d, with the switches `-O1 -ffast-math -mfma` ([godbolt link](https://godbolt.org/z/vqbdGGdvf)), gets the following crash:

```
clang++: /root/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:7791: llvm::SDValue llvm::SelectionDAG::getNode(unsigned int, const llvm::SDLoc&, llvm::EVT, llvm::SDValue, llvm::SDValue, llvm::SDValue, llvm::SDNodeFlags): Assertion `N1.getOpcode() != ISD::DELETED_NODE && N2.getOpcode() != ISD::DELETED_NODE && N3.getOpcode() != ISD::DELETED_NODE && "Operand is DELETED_NODE!"' 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 -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -O1 -ffast-math -mfma <source>
1.      <eof> parser at end of file
2.      Code generation
3.      Running pass 'Function Pass Manager' on module '<source>'.
4.      Running pass 'X86 DAG->DAG Instruction Selection' on function '@_Z3foo4fVec'
 #0 0x0000000003f76d78 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f76d78)
 #1 0x0000000003f74a04 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f74a04)
 #2 0x0000000003eb98c8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x000072e7f1c42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x000072e7f1c969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x000072e7f1c42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x000072e7f1c287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x000072e7f1c2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x000072e7f1c39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x00000000052cd595 llvm::SelectionDAG::getNode(unsigned int, llvm::SDLoc const&, llvm::EVT, llvm::SDValue, llvm::SDValue, llvm::SDValue, llvm::SDNodeFlags) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x52cd595)
#10 0x00000000052bff72 llvm::SelectionDAG::getNode(unsigned int, llvm::SDLoc const&, llvm::EVT, llvm::ArrayRef<llvm::SDValue>, llvm::SDNodeFlags) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x52bff72)
#11 0x0000000002b95deb llvm::X86TargetLowering::getNegatedExpression(llvm::SDValue, llvm::SelectionDAG&, bool, bool, llvm::TargetLoweringBase::NegatibleCost&, unsigned int) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x2b95deb)
#12 0x000000000510cd2f llvm::TargetLowering::getCheaperOrNeutralNegatedExpression(llvm::SDValue, llvm::SelectionDAG&, bool, bool, llvm::TargetLoweringBase::NegatibleCost, unsigned int) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x510cd2f)
#13 0x00000000051214a1 llvm::SDValue (anonymous namespace)::DAGCombiner::visitFMA<llvm::EmptyMatchContext>(llvm::SDNode*) DAGCombiner.cpp:0:0
#14 0x00000000051bbe90 (anonymous namespace)::DAGCombiner::visit(llvm::SDNode*) DAGCombiner.cpp:0:0
#15 0x00000000051bd31c (anonymous namespace)::DAGCombiner::combine(llvm::SDNode*) DAGCombiner.cpp:0:0
#16 0x00000000051bec58 (anonymous namespace)::DAGCombiner::Run(llvm::CombineLevel) DAGCombiner.cpp:0:0
#17 0x00000000051c150b llvm::SelectionDAG::Combine(llvm::CombineLevel, llvm::BatchAAResults*, llvm::CodeGenOptLevel) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x51c150b)
#18 0x0000000005300e75 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5300e75)
#19 0x0000000005304025 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5304025)
#20 0x00000000053052e5 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x53052e5)
#21 0x00000000052f5cff llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x52f5cff)
#22 0x000000000329e06a llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
#23 0x00000000038c12cf llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x38c12cf)
#24 0x00000000038c1681 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x38c1681)
#25 0x00000000038c1f21 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x38c1f21)
#26 0x000000000422ed5e 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+++0x422ed5e)
#27 0x0000000004918b90 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4918b90)
#28 0x00000000065e9acc clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x65e9acc)
#29 0x0000000004918f78 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4918f78)
#30 0x0000000004c0c235 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4c0c235)
#31 0x0000000004b8b83e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4b8b83e)
#32 0x0000000004d000e9 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4d000e9)
#33 0x0000000000da766f cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xda766f)
#34 0x0000000000d9d83a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#35 0x000000000497f839 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
#36 0x0000000003eb9d64 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3eb9d64)
#37 0x000000000497fe4f 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
#38 0x000000000494229d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x494229d)
#39 0x000000000494332e 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+++0x494332e)
#40 0x000000000494b185 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x494b185)
#41 0x0000000000da35d8 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xda35d8)
#42 0x0000000000c28a64 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc28a64)
#43 0x000072e7f1c29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#44 0x000072e7f1c29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#45 0x0000000000d9d2e5 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xd9d2e5)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
```

</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJzkW19v27iy_zTKCyFDomT9eciD4sTdLtqmaHr3HtwXg6JGNk8kUUtSjrOf_oKkZEmO0zZBUhzgLLKJzT_D3_xmODOUWCIl2zYAl87yylleX5BO7bi4fPi3YFLxh4ucF4-X_wsOjveAdqRABFFet6wCV7EaEBVE7pCAlgsFBVIcddLBK7QjbQsNa7bogakd4q1iNfuHKMYb3V0SqdyaqJ3-QpoCrT9nyMGJE3nurY_c8jgAuXVZEyfyHJzqwQ87RnfooUeUMwm0X7iq9jUXW9dPXdYw5abhMnC3NM-9MI4hJUmxcLzM8bKPDo5r1HCFZCcAsRKpHegPEhHUCp5XUCPWILUjSmtbM4UKJoCq6lFD4ELPYcrBsURwaLnUehJUEQWNGiQsELprgbKSUVLZiaxBrNmDVGxLFGu2uq1-RJRXFZBtB8gJvdvVH4-klhoeo1oxDYI0iFcFiAGNg5OjtpHV1l96QeBuIz_ySVIUS7okDk6RNgMRUvOTAxKgMRYL9A32IDQErTqiO9JsAfHSrjZbiuw5K6Qdpm3dc_hHT5huF1B0BipI5VIiYbRTSVgltd4arm8MqD9hzxhdia65d4LMitQ2tj9eph5bKKBEZcWJQptN7eMEbTZEKcHyTsFmo50FJ5vNHqjiYiPZP7bRj4yjmJ_gaiKKNVrQPpTslYJ6FAdfa3HA5ndgfod2gFSiowqteKMIa0AgJ9bNaMBf2mFOfG0_0IpIicq_gPYj2y6vGLWEoImc-pooYueY4Q5OKG_kkRgHR0eUyArkLQiiuHCNeiky40_W15Y1HV0NDk6s5F6M-RJkTpA9s2CtpTrxlQW3KJETXKPaCa6Qlm8FoFHKWTynBN0bIW4vcdBHgOpEg-5H9L30VnAKUvbQ0YBoKlEZYyljLGWMpcJB7iE0y202eccqxZoNIwHeCNq2WmS9GGCMzB6CczNo3Tbwt5k0-sYwR_mWmMWRJpwdHQYhhU23hoKvpu12JeuYoWQOTrUkHM2aDsFxvNVFYeRqPefMDSpb6ozVS84H2vYfmylxts2idnXf1Kv2Fu5I_N6f0DO60n5kwC463duOl61MCrHhh0mbIo6JRdgoxBpadQXIX4jrJt5oGToayQem6A4k-kEuMalmebXlRc4rhSrW3DvLawcnO6VaqT0Wrx287vsXXGwdvP7Hwev933nx4UOxL4fYsEJbUDYMlryq-INWygTKs3GNVkSH_Sv9E-iMtxacKwevtZJuK_i_gQ5f9R-WO3i94gV8gMbB6zuogOocep19OPm6oG3rBFkcp76WbASYnXd3_RepOpi2TKWYli2oL7zQlusaUw8UOlxq7ew-nUr7xKmJN6tJ681f3-cN_aKvb9Rw1hXZSuNIGcqk1AmLN9qsX_zFFtRtSy1m477Y15758e7aSri--XTz_eZ68-X2-sbGxwh9wa-bFrxqmoPxrQ56TaHz5HSEno2xg2OTHsGUJV8_3WR3N0h2uUm6KO-2fVWlU_eJWzK16_IF5fXEU-b-w6TsQDp4bfJsv5XGJI5yQu-VINTw3grodzQUSPJO2GY9k0jJKdM1AxJdgyQVrFUa750i9B4VXd1aP_cWjpd-FXwrSI2I2HY1NEr2Ps5bjWnY3i4c2ooLELpN7weXDMaVri0J8DpnzdBttwtyt8UDEaUbIneLXK7lkrbV0jvVdmohkVtrFpDrHpLIJbJ25WOjyMEJrlmjoEJu2XB3DyLnEnQ_cu-Q624pdRXnFd0R1jjB9Q_x6sGyIa3ccYXckvKKC7dgZNtwqRiVdg3D8bz5XCBCTrDq6Q5uHC_zNYdOsAJeOsENaomQIBBRCJpCF2clq8DxMqyH6ZiAttDorKprai8LdPO3rjFFd6srCwfH664xOx191Q2fSUO2Wo8Y8QbVvOgq0KNmOHCs7Ruek_avJELX2QfXCW6usw_oY2MrHi3_GFN64eWwsBYfepv_C0rOQ1tLxDpbODjwkHfwhv-CMo6KOJkEAfko7YevgjXKONx367LJOEiQhw2XSgCp-6hkAldqIvzbeJ6Dr7xDD09HIwvePwEfEi88B35VAWm69ra5Y9uGVNMQW3G9xHtA1WBGqHgGFfI0oQlaaR_9BpTvQTxabH-Qpqj0iknP4WyMLkfhoPo845n_rfyglx9jiEufhniJvV4pm8AOSbSJQrdiTXdwt01nO-hC8kVkIJspI-BwLjCN0pKiVu0EkGJzz6rqZdLN_FH68hRuGEdoKw0FL4UdxtEoOJoLxklcBojkOoa_SKyZOIqNn4j18xcL9PNRYDIXGKSQRi8TaKaMAtOpgy0xLZbp8pX1xkml0Z9bfm-98dYbsmfE8qVDhzfnKy_LGP9evjIhyOM3KJ1g9ZQanQR-JztG_5GdWWTFebosIJ-g-VcSfSdiC-oTfwDBmu1IEWx1pXJzaAVIaXJR8jPDzwpqw1rOeTX9Ow6eL3tFJNh2sy7LK1jxI_dzOx3Pu29LXU_OSN0s0i99jxa4fFaBI2-rHZAWxK34Ap0SpPoP4fE3kdjTNJIYzEnEfkj8M-cpByek4c1jzTuJGlKDbE1xkvZHguzDitc5a0DYhj2TTK0_Z7Mtd1O36vEzUXTXp1ez-ZLTvefgTOs_kXmShjXucI47zyH1XofytQiWJwiKwKcvRkDtt9diiE4wAF0mL8bwrZv7fN_7CfZQ_RxCPIdA_aWX_zC8r86oPF9yun2utLtk2TeQXaWkIWXa3T8tuG3VEe6b7xij0rhjkpnCgedB_Fz-_3gH1Qxn1hQ3NVMmbiTvAdbCGcGmJ2BDD_8crG3NquqKSEavKk7v5cxcx4PWmIDfQxUN9qgK9k5UWWL4uSqia26bz4TuWAMD6pkqT_reSReNdtTFn9dE5ZKW5Q90-QRbQh__ozSymEeN5scunIIXEfQsKH1An6hzVo-nCixaItRCH53QGXlPYxOeJbcgoT6mU5rXX_W84TnBi-G86THWghv5DE-hR4n_C9A_m8ccc3_om94LdpT4I-zlKewST2FXE0eeKPCxbsf9-lvBl3gCfpZNQ4yhWAKyswwYqJm6IvQemuLWPIZzcDLpXvWQPjZSkYZCXxrORgzZSsN7cnC5U7pE1AeVWfPAQXYirYeS0eE98zjlY6NEJ9kevkG5atRXJWaF2L7sd9-aVXD3KBXU_TlIqsL2dA37u4NNezJTkIdN-yCYgs3wHGoyqYCSdJXaFFCBgp9MDG76NZ-qtLLvVkRfA72x3XvLjnaflTBh6id56v0IlWm0z4--C9LIyjyV_J-GnThEdvd9KHTfxYF7qKMis9IkWkJKKJ0q8pUICdnd9znMO6jJ2WPMmwPuIY2A01Pmyzg5s2F6F7eHiAPQTsHg9e9RRfVAjjDnz25D6lEcLKcw10Kb-bgVpzjfCaHFMCKcFRRhnuRJAOhHseksl8-r9D7-a3GOWsyKiLDwPA_SqRY93lGZPafkKfangfhdwojFN6KfVRteQeIoKhGl_qYmbJ7VJg-k6I6IoYzOhoA4a8MrtOeseB8lLMpRh3CuQ1okAUED7Sv_u4kL07NqTarqL3OZxCbxMwqdZDktow-Ls_NDIdj-3AkzWM6DRFwmQWoomQgd3sBshGHV9NqtZ_KMOWqTqsoJvd-UjYY5uotduHedlb_idU2a4nQXn7XeMfNxk9JJNX_EeMznx1x3nLDZ0MPB9-2XXJ-zdF40D6oMhbPBumGjBGFKDt0n4khV6a3AxaRfD8nGaJ5NbsZk5vVqXJE6L4iD45EqnAwvav7k-RljRKevV4po-ibo3EuU41OGO1JC9Tjj8sd2e4eazyIeHT4-dS4IS_Tf7BwnB63zXpDMWQsxTotnWTNWI08y40DlLHSfTNQDZk_5f21oNitn3ulRaq_26EonxUwYBBheSsqfPJfPM_Inzz8xqZ557_E0Fh89oCVMG3-45vKLJPZu8luo1GQdqQy9EypzP1k-B_t68nlWIJypDJ4zwW-k8h2qVUPPSJ5_UocEy6IvqodKZABvQkn25KHqcxn6zWsPjWzEPav-PIoTEoVII37rha3oceGTV_o4LdIXvtI3U0aB4alACD202eg5G6mIUJuJWr-8BISTJZanhRqGJbLC39xORrhd-uRKHwihs0pm3QuV_aHBXKfW_m-vfNnrinBg2p0KQH4QaoydBOTukeJIAiA2KebT461JEP29TtDbT888uWN4UVwGRRqk5AIu_TiMojDywvhidxlHQbwsipgQINQL86W_zJMyjEmZRFEKcMEusYeX3tKL_RTHOF6kUVyG5dL3ooQmJPed0IOasGqhd8aCi-2FuWh26QdJGoYXFcmhkuafEmDcwAMyvQ7GzvL6QlyaO2p5t5VO6FVMKjmKUUxVcDle8lsTVnUC7P2xH9-jszfwoUCkVCD6i-aoa-0zleEa-_S66EUnqsvXX6nrld1f4v8PAAD__1iyCrg">