<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/74464>74464</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Clang-18 crash when compiled with -c.
        </td>
    </tr>

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

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

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

<pre>
    Clang-18 with -c crashes on the test case.
Compiler explorer: https://godbolt.org/z/KP9xxjE7e
```
$cat mutant.c
extern char x[], y[], z[];

void
func (void)
{
 __atomic_exchange (&x, &y, &z, 0);
}

$clang-18 -c mutant.c
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: clang-18 -c mutant.c
1.      <eof> parser at end of file
2.      mutant.c:4:1: LLVM IR generation of declaration 'func'
3. mutant.c:4:1: Generating code for declaration 'func'
 #0 0x00007fa71a5f7266 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xd2b266)
 #1 0x00007fa71a5f5170 llvm::sys::RunSignalHandlers() (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xd29170)
 #2 0x00007fa71a5f68c4 llvm::sys::CleanupOnSignal(unsigned long) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xd2a8c4)
 #3 0x00007fa71a544bb0 (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xc78bb0)
 #4 0x00007fa7250d8980 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x12980)
 #5 0x00007fa722ded116 clang::CodeGen::CodeGenFunction::EmitAtomicExpr(clang::AtomicExpr*) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1af1116)
 #6 0x00007fa7230119b5 (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1d159b5)
 #7 0x00007fa723009bdd clang::CodeGen::CodeGenFunction::EmitScalarExpr(clang::Expr const*, bool) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1d0dbdd)
 #8 0x00007fa722fb9ce9 clang::CodeGen::CodeGenFunction::EmitIgnoredExpr(clang::Expr const*) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1cbdce9)
 #9 0x00007fa72311251f clang::CodeGen::CodeGenFunction::EmitStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1e1651f)
#10 0x00007fa72311f4dc clang::CodeGen::CodeGenFunction::EmitCompoundStmtWithoutScope(clang::CompoundStmt const&, bool, clang::CodeGen::AggValueSlot) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1e234dc)
#11 0x00007fa7231795ba clang::CodeGen::CodeGenFunction::EmitFunctionBody(clang::Stmt const*) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1e7d5ba)
#12 0x00007fa72317a22f clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1e7e22f)
#13 0x00007fa72319a0e5 clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1e9e0e5)
#14 0x00007fa723193bf1 clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1e97bf1)
#15 0x00007fa72319792d clang::CodeGen::CodeGenModule::EmitGlobal(clang::GlobalDecl) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1e9b92d)
#16 0x00007fa7231928e2 clang::CodeGen::CodeGenModule::EmitTopLevelDecl(clang::Decl*) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1e968e2)
#17 0x00007fa72322e75c (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1f3275c)
#18 0x00007fa72316fefe (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1e73efe)
#19 0x00007fa721d8c93a clang::ParseAST(clang::Sema&, bool, bool) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0xa9093a)
#20 0x00007fa723be4645 clang::FrontendAction::Execute() (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x28e8645)
#21 0x00007fa723b62cc4 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x2866cc4)
#22 0x00007fa723c5f1c0 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x29631c0)
#23 0x000055f1d6a97837 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/usr/lib/llvm-18/bin/clang+0x13837)
#24 0x000055f1d6a94905 (/usr/lib/llvm-18/bin/clang+0x10905)
#25 0x00007fa7237fa909 (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x24fe909)
#26 0x00007fa71a54494c llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xc7894c)
#27 0x00007fa7237fa2ae clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x24fe2ae)
#28 0x00007fa7237c20f1 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x24c60f1)
#29 0x00007fa7237c233e clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x24c633e)
#30 0x00007fa7237de39c clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x24e239c)
#31 0x000055f1d6a9425c clang_main(int, char**, llvm::ToolContext const&) (/usr/lib/llvm-18/bin/clang+0x1025c)
#32 0x000055f1d6aa1f32 main (/usr/lib/llvm-18/bin/clang+0x1df32)
#33 0x00007fa718adbc87 __libc_start_main /build/glibc-CVJwZb/glibc-2.27/csu/../csu/libc-start.c:344:0
#34 0x000055f1d6a911ea _start (/usr/lib/llvm-18/bin/clang+0xd1ea)
clang-18: error: clang frontend command failed with exit code 136 (use -v to see invocation)
Ubuntu clang version 18.0.0 (++20231018091808+48a53509e851-1~exp1~20231018091910.1571)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
clang-18: note: diagnostic msg: 
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-18: note: diagnostic msg: /tmp/mutant-fa8676.c
clang-18: note: diagnostic msg: /tmp/mutant-fa8676.sh
clang-18: note: diagnostic msg: 

********************
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzMWl9T47jy_TTmRZWUJP9_4CEEwrI_9jcUsLNV9yUlS-3Eu47kkmQmzMN-9luyncQKsANM7q07RQ22LKvPOWp1tyWYMdVKApwH8UUQX56x1q6VPq_YhkklnzeqNdycFUo8n89rJlcTkqFvlV2jCUdcM7MGg5REdg3IgrGIMwPTAF8GeDZXm6aqQSPYNrXSoINwhtbWNiYIZwFdBHSxUqJQtZ0qvQro4ntAF_93l2-3f16l0I8RJHj46W9pxJlFm9Yyaae8b4StBS0RXzONtj2NgM7R8-Hy-3AZXgzDdP8_qUr0V2UrOQpo1rXQfOiUDr3Rcsms2lR8CVu-ZnIFrm9Ak60bO6DJ8_D7u_uN3QB7Q-nl2KKDvxNxwo9o3N1ezR6ukGmLTWURQ0W7QhoapS2y6li3yq7bYsrVJqCLun7a_Zo0Wv0J3AZ0URnTggnoAjEpUCV53Qro5qmbNlQw_pfVjIMD3WhotOJgDAhkVKv7ZvcmM0bxilkQSLcSGa6rxg4z_GAZ_wuJdtM4ZF0TnqI7rVaabRDTq3YD0jrY6G3eZIq6f0E4B1UG4RVqmDagEbMIpECqRGVVD_5Ah877IcJZFIQz4kzc3n79Dd3coxVI0MxWSrp3BfCaDbcBTd1UBzTtRwunrw50PQwgV4grAahU-h-HQQENMcJbjDFOS5YSFpcpTRLUzUw4C8KZeTb9xZ2upO10e-zFzw6dNPu2VMZqYJuAJm4CKmkDmvfutmiNdtNcFbvJJq61qGRAF9Pp4VFVOCUmJJsaNSUBvcBbQQuaJHvXdoDJEeCYpPg1wPetfKhWktW_MClq0KYDcxJMOUmxh4keYUoyHr2GaV4Dk23zZUAW0KyVXRgTqFZydSJ4LOORBy_04UVRUeCfN8TTrCh8HaKRIRpjkeUZRsulBmOVhqW2g9V-0G2WLJNoUley3U5Wsu0fNHatgQlnB3d2CM0z30w8NkMFCEKSfqEOMisB1yC9m0UruVsEfePVprKzLjZebRsd0Gz09rh99pkp6UMGb5pOq6wnwUpCiO_JyZhGiAnJi_g0xgSJ8yL2jKW-MZwXQnxcswfOaqZfauZaEFfS2E6zOSqUqk-mncCiEMKjk3kuUBY5h_zjdG5WUmkQP-RzIh68EBxyj0fuTQshNCblJ6bFbqxPwLV4E3KIRjOt2fM9lEE497zejhiHVycjDSSJSXmoTmhI8BHpMhL846RdmaZaKRzVPyq7Vq194KoBX4hxrx2_5OCh8zftzlarr6xu4aFWn8plr4tBw0hwTwzii5HmccE-Lsau5UKJ53_0hFMRSUVcMI8IPSLCKP2gKw_1C7iHPonrWhWsvgRe-768f7938jetXe863shSjdzgZGoApb6Ph74aOcMQ_0iN35RoazhMas96B_0SykpWPdv3aNO3dz580pnPAUPscY2OuIZFST7H9X-GY1qUxOMYH3FMc_rD_Pk6x7eZnQx9kVPhoU-O0NMM6EfRP6rmFp5gwDrm0LecUv4kA-oR8MsXSiGN-WmMlSFNYz8kZ75aSQklnCpQhFCCZ8yrAIjIeB568f_OfVTOHh6Pojps2FEiO2XJxXKch154p37SLiBKIi-gLbSSFqSYjTPTFnhr4ZNfXq8BoxlkSeSFH-pn0CKhnEfoqASoatA30lgmOXjYBrieuEdUTpcoaJYkfPRx5tD7aZPHJeEYeaVoh_NA4klx9hLzC5KnW480T0LCsYd6l97iuCQiYXmahSninCw3zI2avV5urtlRjTlHfhudo34v653gewG6pRVmYepBjI4gRjl-z-fVaEicY9_T_CSQlm6ZnEbiqIQc556x5PirPY_4KPXNNTPre-DqCfTz3Dns1h52PlgJ9bM3D-VQRix1NxdO5h56_slq_7UNgTzyIilNjwWjDMbOLXT11O2vOkJzMlebDZPiOHi86kzGDv1U42ixOgjnh44PVldy1fW8Gjxt_8JyybdbQvqbgpmKL03XfXBRr7NrWFrNKmt2j4-GY3XtVqTSo-euy-g7uPPmzslP5i2UeWmE-jkr5RT7NZindBcr2Is4vZPfCyxHL7oO3nfU-7rOvGR1WjF4gv1ijebHYoTh2273hhi_qsK8rcSvqritjP9FOfK-Davrr8Ct0jebph57a8Mq5yjdBun7xRtc6j8oYRh6_hT66T4VEOb8LbiXo2svXb2Sp96S_r8o4alCNtAw98Ldfm96n3JoPIi2y4s70F2Ymb3Ym3lUqh5i-Qe_Usdpi_r17H57eoDFXM2LHKCPjSvK0CvK_X3ljImCZylaLp1gS2OZtsvByKJoq1oEdLFyzybzr79--1exv6VTmjpLpt0J3192D7txumOOMIqCcIYP5o8TPCHAUG_4Q8QEgUOpuzvvCcIZAq2V3h8CoXIoCxEffKtkVQ2iP1aEbWX7UxcSJs58awBNnpBVyACgalS2DZZ-L1pp22HsJ9CmUhKRbIqnw-b8RUAvKKYhwSTDOcmwa4syFocxziGLyYT8DduG_D3qlBM8JXF6CIePTK_AFQZo2G5v-GjHve_SbbijjRJQu46NMtW2f9RVk3UN4rLqhNhr6jR8oZdU1hXXSFRsJZWxFUcbs-reGybtJ35Gx5HDiePs8XE2_wU9_nKFFl9ub7_8cfP_12hxc3v1gB6_dM0Xv1-j-6u7L_eP-3O-u9dODDPjFtmbp4b7DhpQl-tBIGb3Q75TArqwmyagi_7kblKyLEmT3WHiT41h1p-Yi1PNyO6g-0ychyIPc3YG5yTFJM1ImqVn6_OsgLhkOcmBsJKEBclSgcuycJ8MGcnSs-q8c2CKYxLiPEqnCYkYMBJxTFMRQhZEGDasqqduDU-VXp11h8TnaRQl0VnNCqhN93cAlEr4hrqHAaVBfHmmz7t1X7QrE0S4row1h1FsZWs4_HlAf778bQ3SrfDmsLYnfHrW6vr882fZHdJ_BwAA___Cno76">