<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/136540>136540</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang] compilation (instruction selection) failure when targeting AArch64 architecture
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          JustinKim98
      </td>
    </tr>
</table>

<pre>
    I tried to compile following code in newest clang built from source in current main branch, but there seems to be a bug in AArch64 nstruction selection.

This happens only when I put -O3 option for optimization in debug build.

Here's the compilation command
```bash
clang error.ll  -c -O3 --target=aarch64-linux-gnu -o error
```

```llvmir
; error.ll
target triple = "aarch64-unknown-linux-gnu"

define i32 @error(ptr %0, i64 %1) {
  br label %3

3:                                                ; preds = %6, %2
  %.sroa.0.0 = phi <5 x i64> [ zeroinitializer, %2 ], [ %.sroa.0.24.vec.insert, %6 ]
  %4 = phi i64 [ 0, %2 ], [ %15, %6 ]
  %5 = icmp slt i64 %4, 5
  br i1 %5, label %6, label %16

6: ; preds = %3
  %7 = getelementptr i8, ptr %0, i64 %4
  %8 = load half, ptr %7, align 2
  %9 = insertelement <1 x half> zeroinitializer, half %8, i64 0
  %10 = fcmp ule <1 x half> %9, zeroinitializer
  %11 = insertelement <1 x i64> zeroinitializer, i64 %4, i64 0
  %12 = shufflevector <5 x i64> %.sroa.0.0, <5 x i64> zeroinitializer, <1 x i32> <i32 3>
  %13 = select <1 x i1> %10, <1 x i64> %12, <1 x i64> %11
 %14 = shufflevector <1 x i64> %13, <1 x i64> zeroinitializer, <5 x i32> <i32 0, i32 poison, i32 poison, i32 poison, i32 poison>
  %.sroa.0.24.vec.insert = shufflevector <5 x i64> zeroinitializer, <5 x i64> %14, <5 x i32> <i32 0, i32 1, i32 2, i32 5, i32 4>
  %15 = add i64 %4, 1
  br label %3

16: ; preds = %16, %3
  %17 = extractelement <5 x i64> %.sroa.0.0, i64 %1
  store i64 %17, ptr %0, align 4
  br label %16
}

```

Here's the output
```
clang++: warning: argument unused during compilation: '-c' [-Wunused-command-line-argument]
clang++: /root/llvm-project/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp:6598: llvm::SDValue llvm::DAGTypeLegalizer::WidenVecRes_SETCC(llvm::SDNode*): Assertion `InOp1.getValueType() == WidenInVT && InOp2.getValueType() == WidenInVT && "Input not widened to expected type!"' 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++ -g -o /app/output.s -fno-verbose-asm -S -x ir -fcolor-diagnostics -fno-crash-diagnostics -O3 --target=aarch64-linux-gnu -c <source>
1.      Code generation
2.      Running pass 'Function Pass Manager' on module '<source>'.
3.      Running pass 'AArch64 Instruction Selection' on function '@error'
 #0 0x0000000003ef1728 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3ef1728)
 #1 0x0000000003eef3b4 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3eef3b4)
 #2 0x0000000003e33ef8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007381dee42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007381dee969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x00007381dee42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x00007381dee287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x00007381dee2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x00007381dee39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x00000000053428bf llvm::DAGTypeLegalizer::WidenVecRes_SETCC(llvm::SDNode*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x53428bf)
#10 0x000000000534dffa llvm::DAGTypeLegalizer::WidenVectorResult(llvm::SDNode*, unsigned int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x534dffa)
#11 0x00000000052f6e4b llvm::DAGTypeLegalizer::run() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x52f6e4b)
#12 0x00000000052f7c39 llvm::SelectionDAG::LegalizeTypes() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x52f7c39)
#13 0x000000000526a843 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x526a843)
#14 0x000000000526e0c5 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x526e0c5)
#15 0x000000000526f385 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x526f385)
#16 0x000000000525ff2f llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x525ff2f)
#17 0x000000000321baea llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
#18 0x000000000383d41f llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x383d41f)
#19 0x000000000383d7d1 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x383d7d1)
#20 0x000000000383e071 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x383e071)
#21 0x00000000041a85de 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+++0x41a85de)
#22 0x000000000488fa5e clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x488fa5e)
#23 0x0000000004b81c05 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4b81c05)
#24 0x0000000004b00bde clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4b00bde)
#25 0x0000000004c70e6e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4c70e6e)
#26 0x0000000000d9decf cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xd9decf)
#27 0x0000000000d955da ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#28 0x00000000048f57c9 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
#29 0x0000000003e34394 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3e34394)
#30 0x00000000048f5ddf 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
#31 0x00000000048b82fd clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x48b82fd)
#32 0x00000000048b938e 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+++0x48b938e)
#33 0x00000000048c11b5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x48c11b5)
#34 0x0000000000d9ac18 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xd9ac18)
#35 0x0000000000c229f4 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc229f4)
#36 0x00007381dee29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#37 0x00007381dee29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#38 0x0000000000d95085 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xd95085)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
```

Check this out 
https://godbolt.org/z/nP11TYxqW
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJzkWl9v27iy_zTMC2FDoiRLfsiD48S76d29LZqii_tkUNTI5o1MakkqcfrpD0hK1p84TXOQLA5wiixWJjkzv_nLkUiqNd8JgEuUXKHk-oI2Zi_V5adGGy7-hx-W2UUui6fLW2wUhwIbiZk81LwCXMqqko9c7DCTBWAusIBH0AazioodzhteGVwqecBaNoq5FaxRCoTBB8oFzhUVbI_IGueNwWYPCrAGOGgrJQdMcd7sLNVqpdh-EWOhjWqY4VJgDRW4pzkKVihYfdtzjfe0rkFoLEX1hB_3IPAtrhuDZ58jLGtHV0rlHg_8B3UDXOACrByLt2i5_Q4KEEm1BdXq61czeThQUdhVi8D_5VTvUbDySoNSUs2rCuMZc2JnM0PVDgyKril1WswqLprjbCcaPJOeYMjOAzj9rKqHA3cLoqsTdxSsPFfrlLoCjKJrjAjpJDTiXshH0UtChHi-BZRcAOYRwSgOvHCS1UZhRJLAuoIvYvscIrLEKL1CwQrjXOGK5lDZicgzilC0wm_8Z1WoFRS6xZssrEBEEuKkIJLMtZJ0HswDt6Lec4yidYKPFhWKbjBKrvAPUJILbjit-A9QHQuMkmv3nFwNOZF4_gBszoUGZdq1C7e2FRmfRDnNkyscvMAyTM7RJ46es0ONdWU688V2adIZj4dupR072XEx-hUuvFkX1qzP7BR1wlI3sgMDFRxAGOs4nllOZ1wYd1SZo6okLfCeVuVgeWqfacV3Ap98sPQKOYO1YqwXQnz01NHNORfYKSerAxB0_ELvzNJaqHGxOuJlJVqaKc-OOnwZThsUZ9AMvTAGQxw7vW_KsoIHYEaqaYwNwtA5fDR7LvpaNBFx5NHaZleEopuT0MgLdSXrtDxshYXBkMkJQ0jOD4eWq32Iz2syWR4953JeheSZCj6WIoJrybUUb_jVq342DV91wU8Q9prFrwMPuwfSPSTdQzz0j89hWhSjwAlfqn3h-SwNu3J2StfQ5yscjaJsGL0_CbdT_bU8tJEKTkPpNNF95sbPcPpqkl5P9pIze5tsTN2YySK3lSFyZf-iFX6kSnCxs49U7RqnQyMaDQUuGuX3_9MO6SxD0hlDJLWFc_aXXzprd067J8Gs4-Pr6EQeIhslpUFkYze_Wa3k_wPrftr_8RyRzVoW8BsIRDZ3XStwvfoNkc0fsHNh891F1renGvSc1TWKVotkmVkBjk-0QtHq7vo7rRoYjFyvfrMkHRPlR__iBYjvwL6C3t7dfFuvEcmGXP5XFoDICpGl5b_SNsptu4AWwa34XIfzHRgnyfJGJHOba3Rtg8OxvhXfv2FEFogssCUgbyFAhNwK2-YIafCjnfV9GhxrYMY-Ox6hbQJIikvKK3CNzpc_blZ3N1g3-YGbtttSUEtlLPnemFpbBckGkc2Om32Tz5k8DBwxdg_XugGNyAZTUWAuWNUU4DsoRfUe55Td20QAF8YKaiUZaBtGvj90ES0KTLWWjFOLXDUCa6Z4bSzeO0PZPS6ag3UmClbBHAXLL0ruFD2cQlO3ISRri6ntVdUMjnUlla0lGxduM9o5Sc-MasQ9Ipuci27aRyOe7WyPhsiG1rXl6bJlrvGsFHL2ACqXGmZUH_DsDs-OmCs8K5mspJoVnO6E1IazdrWzwXj41faQ2VrRGseVq9BqbCMf70CA8hkXrIgd_toIm6a4plrbFNw0wrfKX-zAn1TQnVU_xVLggyzcVkzSkQCSWjNH57h1LfjtoAc_JV7LtewkWr6n7jL1G1YU4OAYdP8iKMOUZIPE00_aP3xRXBjn6m8-WAaZpujjVmqjgB5c8K8xF8blhk2Rd_E5IlfBsYVn89mDD8fgoYzy-Bz4dQVUNPVnccd3glaIZI1wL1gFrqQV8QFQHZgeKhlDjSIoM7y20fcVmHwA9eSx_U5FUVmJWWvD0Zq1FAaOpq2cgfvP849a_mmUhQVATBIStEr5ynzMFtthHPsJNtdyvnCQHUkPOB4zXC6WJcO12SugxfaeV9XbuDv6nnsyhRunC7zTzgRvhR2ni57xYsyYZGkZYZrb6vkmto6wZ5s-Yxvmb2YY5j3DbMwwWsJy8TaGjqRnuBwGWBLFJMvLd9xB3ztBWoQev03lYIK_KEv6y_iNVF9BN5V5Cf8anzL-Y2pTi7jXZ1SbElIuIM5f1Uc1omsr3hmeB9DDIxN4KYuWwxZs2L25kQ6pa90-DKSF0YOMxiAXNIujF0De3kHVFnvfgq5EcXPgxnWfHwPWwenBxhOwELDkVbB-dFVVV1RzdlVJdq9HMXzqF5gU2rjt9SNUsWB7VZKJKmWUva6KasRn8Sdley6gQz1S5dncB-li0fa6LMa6JGVJyp_oYsOcPf1naeQw9xqlo1aChDmFYaWcgLJ95kCds3o8V2BeU2Xsq-8Sn-E36T8sqGwEKouKOByaefPF0nXt7pvhvGtr5sH19lxOoadF-AvQ_3Td-jge2qGPgp0W4Qk2CSawIUiHsKtBIA8UuD3U1XCv-cfAW3g9-NHuGIc0SwrwJxQeDBy4uaLsHkTx2X8MIdlget1Csu89VDBoXztGK9wu8NmdL-h2fpD2RnGx-wrleLizwWrCrYWyasNySHIrjGo0f4CvUK6F-WIUitb99EPZZt-GV3D3pA0c3DvdGmtT-JlG8L8b2NYTSvtWVT8qbmDbvVsNiAooaVOZbQEVGHiFMLppZT5XaS2Fbg7Wpx_R5bWe7f0-ajviLCtpAmfc1hraDd0cgTUGOtt_xF7eAulhjhqPOM9CFiRDmBtlX8ROATHE-UEIPYYeYTxGGAR5MTHkJEPO2vJllT6kDLQ4ey1GjUbM0gAWIy1avL0yD5LR59ifl4MPCWaPr0c_ai2CYlkAKzFj4fZA-bi2rpSiT7baRGu2p6pr5lZdWo7GyBo_SF58jBIeZa9DOtEhSQqKO7Ovw29SVuN3qgOtKv_G5beSMwpNaq3l0X64GHWxheIPoJ73EiQbF4kySdnSmWTAtPuqtVXOqm7Wp56rdnYJo1WVU3a_LYWF2YeLF9yGzjpct6fHkyw-671T_fUH17QaVd5-VzlV3BPBdsuOxzD0P3Lb7dvq7L7gOxOOFtuBrVGUG91NT9jRqrKpINVg3i5x4ZM7r7nw8QZ3JIikFT3kBUUk7U1Fsu4T2CeZn3HGcvLhKo6Ww29s5z5P-ZmvjbijJVRPI1v-3G8f8SHOIT4F_PiDpw2uoijxf3NwTNr9s1Ew_tIaZ3lGyuJFq43OnUZV3JlyVLonhHbBoEisfyJjuHTVrva6DRR73y7Bqd2H0qSZyZdRBm81yieZ65ct8knmf3BtRhb5WS0-RUBNuXW--9b160Zsw-QfMaU1Vm_KccOVsTDMk5dgXw-eRw3Cmc7gJRf8g6b8gG7Vmac3XjzZwykLMw-060Q68K6UrNpC8PoO_e69h0XW4x51fwEjZFnG_g7aOwv2rHvB00OCZbF842GJI-kZTo8HlhAHeLu1NFttqDLbgVq_LALigYhs2qgFWYI98_f3k2XuRU9uAfjTw2jV3iYs25eG7gZee4yNH7nZYzhy4y8hhlFsMTYa8OwBG4k1AOaDZt5K6pp4rMA0SoBNP0v5_K7Eeg_sHps911g2BqNgNTkVl0UuKzOXaofI5gciG_ElDL_93_Hvvy6Ky6hYRkt6AZdhGickXMRReLG_XKbhMs2KMigZ0CJME0YgyyCiaZmxPAwu-CUJSBLEJAwWJIjCeZDmRV5StigWSyjSBYoDOFBezW1eWdkX7uj9MowWSRxcuGsg2l3oJKS1KkHJ9YW6dCf2ebPTKA4qro3uWRhuKncL1FMk16N7jy6zz9y-tLlrPdEo8Bcu_XE2F7vTpU2q2J4bYKZRcNGo6vLfv1jQKvhwSf4VAAD__05u5HQ">