<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/111626>111626</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang crashes at -O0 on x86_64-linux-gnu
        </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/74WYz7xW6
```console
<source>:6:25: warning: implicit conversion from 'unsigned int' to 'char' changes value from 3735928559 to -17 [-Wconstant-conversion]
    6 |     *shouldnotcompile = 0xDEADBEEF; // Force compiler error/warning with unaligned memory write attempt, to make it easier for testers and authors.
      |                       ~ ^~~~~~~~~~
LLVM ERROR: out of memory
Allocation 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-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 -fsanitize=undefined -fsanitize=address -O0 <source>
1.      <eof> parser at end of file
2.      Optimizer
3.      Running pass "asan<>" on module "<source>"
 #0 0x00000000039400a8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/clang+0x39400a8)
 #1 0x000000000393e214 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-trunk/bin/clang+0x393e214)
 #2 0x0000000003890678 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007ff1e6842520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007ff1e68969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x00007ff1e6842476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x00007ff1e68287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x000000000389ae80 out_of_memory_new_handler() ErrorHandling.cpp:0:0
 #8 0x00000000038bce3d llvm::SmallVectorBase<unsigned long>::grow_pod(void*, unsigned long, unsigned long) (/opt/compiler-explorer/clang-trunk/bin/clang+0x38bce3d)
 #9 0x0000000003980274 llvm::GetShadowBytes(llvm::SmallVectorImpl<llvm::ASanStackVariableDescription> const&, llvm::ASanStackFrameLayout const&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x3980274)
#10 0x0000000003980316 llvm::GetShadowBytesAfterScope(llvm::SmallVectorImpl<llvm::ASanStackVariableDescription> const&, llvm::ASanStackFrameLayout const&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x3980316)
#11 0x00000000035ec629 (anonymous namespace)::FunctionStackPoisoner::processStaticAllocas() AddressSanitizer.cpp:0:0
#12 0x00000000035efba3 (anonymous namespace)::FunctionStackPoisoner::runOnFunction() AddressSanitizer.cpp:0:0
#13 0x00000000035f2c33 (anonymous namespace)::AddressSanitizer::instrumentFunction(llvm::Function&, llvm::TargetLibraryInfo const*) AddressSanitizer.cpp:0:0
#14 0x00000000035f4855 llvm::AddressSanitizerPass::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x35f4855)
#15 0x0000000003bc901e llvm::detail::PassModel<llvm::Module, llvm::AddressSanitizerPass, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x3bc901e)
#16 0x0000000003313137 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x3313137)
#17 0x0000000003bd85eb (anonymous namespace)::EmitAssemblyHelper::RunOptimizationPipeline(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>&, std::unique_ptr<llvm::ToolOutputFile, std::default_delete<llvm::ToolOutputFile>>&, clang::BackendConsumer*) BackendUtil.cpp:0:0
#18 0x0000000003bdb91f clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, 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-trunk/bin/clang+0x3bdb91f)
#19 0x000000000425c554 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x425c554)
#20 0x0000000006228cfc clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+0x6228cfc)
#21 0x000000000425cc75 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-trunk/bin/clang+0x425cc75)
#22 0x0000000004524651 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-trunk/bin/clang+0x4524651)
#23 0x00000000044a429b clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x44a429b)
#24 0x0000000004608bb3 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-trunk/bin/clang+0x4608bb3)
#25 0x0000000000ce032c cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-trunk/bin/clang+0xce032c)
#26 0x0000000000cd8d8d ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#27 0x00000000042a5419 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
#28 0x0000000003890aa3 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk/bin/clang+0x3890aa3)
#29 0x00000000042a5639 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
#30 0x000000000426c87d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+0x426c87d)
#31 0x000000000426d87d clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+0x426d87d)
#32 0x00000000042772cc clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x42772cc)
#33 0x0000000000cdd081 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-trunk/bin/clang+0xcdd081)
#34 0x0000000000bb0634 main (/opt/compiler-explorer/clang-trunk/bin/clang+0xbb0634)
#35 0x00007ff1e6829d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#36 0x00007ff1e6829e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#37 0x0000000000cd882e _start (/opt/compiler-explorer/clang-trunk/bin/clang+0xcd882e)
clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
```
Code:
```c
#include <stdio.h>

__attribute__((always_inline))
inline void fail() {
    char* shouldnotcompile = (char*)-512;
    *shouldnotcompile = 0xDEADBEEF; // Force compiler error/warning with unaligned memory write attempt, to make it easier for testers and authors.
}

int main(int argc, char** argv) {
    (void)(argc); // Eliminate \'argc unused\' warning.

    void* arr = __builtin_alloca((sizeof(char) * -1024) + 512); // Cause "argument to ‘__builtin_alloca’ is too large" error with some compilers for educational purposes and create unaligned/offset memory layout (warning).

    char *victim;

#ifdef __LITTLE_ENDIAN__
    victim = ((char*) arr) + 1; // Set a pointer just before our aligned data structure, forcing the possibility of stack alignment warnings.
#else
    victim = ((char*) arr);
#endif
    fail();

    printf("I didn\'t expect to reach this line.\
"); // Only used for error analysis if above warning/error-prone section doesn\'t generate desired effect in compiler messages (should never be executed anyway).

    return 0;
}
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzkWktz4ziS_jXwBSEHBVIUefBBlqXp6nBPVVie7tgTAwSTEqZIgAuAtlWH-e0bAKgHaLlertjd2XXMdNkgHl9--WUiQYJqzbcC4AbNbtHs7or2ZifVTclTdlXKan-zlG3HG1B49dI1UoFC8QLvjOk0iheIrBFZb2VVysZcS7VFZP0FkfU8-es_vsxf_kpRdIeiBUoj_z8mhZYNDK3xUsteMUDxCsWLFMULMrOzP1MluNjaX3nbNZxxg5kUT6A0lwLXSrYYkXkvHPQKc2EQmWMjbSvbUWX_YjsqtqDxE2168GPieTzLSTab5bbvZDrHaHY7-cuCMlSYyWkNNLvzGDHGOMVovrS_YEQWeif7phLSMM8LRvEdjl7uVou729VqjeJb7EnBa6kYYHagD5SSCpH1YBx-5maHe0Ebb0MLrVR7_Ky4AUyNgbYziCwt0JZ-BswNBqo5KFxLhQ1oA0pjKirsPaavT4DxEfDrn39hNFv96_Djx9zf__kHXj08fHywlMveYFkPgHyHRdNIRo0jn_IGKt_86X612Kyw7suWG0xx2W-xgk4qY2GPNMLNri-vmWwRWTfN0-GfSafkP4EZRNZc6x60pc6axQVr-gqw2QFmiuodLin7bBRlYHnpFHRKMtAaKjzIiCw9IVpLxqmBCqteYM0U78xAz8ZQ9hlXfdtZZK4pukZR_knJraItpmrbtyCMBW4dKa0X1gcnTuAQA2TNGiq2E6N68RmRdcnFoQ1PttUzVfUkwZMtnlhRrmnX2cl60_XmWuNJa03Hk8lLlk6obid6Lwx9QfEdFwYaPKmFnDyBKqUG-xxPNngy2TI2MVI2bEe5QPHdV-HZzlrQTu-kwZOayUaqScXpVkhtONN-DUfsqFlTwQ3_Aii-60UFNbfyDJppVSnQGk8-RjgIYsfn1PKJ4iXIGsUr3FGlQWFqMIjKCqvmhwRAbM-PneEt_wLKt8W27aEXLkY6qjVGhFBNBYqXdglCsBS4lVVvY4-QYH1ChiBAJI5w9BIdfuI8iSKaYSe8eIHihd5r_8snxYVxsnj02spOnRR9LqQ2CmiLSGr15VJNjhHJfk4ciNxGLwMaRPIT3GkINwYyTS7BXTZARd99FBu-FbRBJDumwUba-d8Pzq0dgCMBuCyP0nmGl1Y7D8DkE6i9R_MbFVVj18gGnoI-SykMvJhr1tngi9z_j0vEwxLzup5CmiVkRqLBkoaXiKxfsrRIk0nDRf8y2YreP2DXWl6nDrgbEsBOwjnzNK8Z7sxOAa2Kz7xpfmwBNz5YYDYGncxTvNWOix8Fn8zTYO40nJtk8zrGtLTJ9YdmdgODmecjb1LIIpv1C1kXPusXAp6L3dGZ1pMru305_3KxvezCLJy3ZBBXZxLetLRp_gRmpLqlGlC8DJXrigAUL7ZKPhedrBDJniSvEFnYwBup_FXDu2Xv8QZE5WFMZhGZn8fk38BsdrSSz7d7Y_et7KKtH9quQfHy9GyxocLlmz-p4rRs4A78FmXrjniFXTkypJsLo9aKtnBP93abPnV9f9Q7647m24wUjc2Pp-mb5i9qA2rDZAf__kTE0zQgIszNM2CpX4YKKfat7DUWtAXdue0j9zDXvWDWEAf1k-RaClc6o3gx1C0bQw1nvrTSQ5Qt_M66GfZa9TrQLB4ywlOXNH4HHtWLj-Lw_IeAxCGQmrD4m0DGM_tWLrRRrvI6A3Jy-qlxpIZHqrZg7nmpqNp_ELU8SGHx_VYkIyuSbDY7F9xokk9U6yNxAco_XFXyWrGCNnvN9R9U0K01ePlqiK1dfoV4PfhAvLPAupLl0RTOwFVgKG-GUohq_YesoLkEMTTpEic_YfQh5__vY9ITFTCZBkzG03gaz8_AOfbeBvZ_ih1vfMBOWFWUVTaD8lu5YNVys9Aa2rLZ_wZNd8gGD70YjgXu0PmJd9BwYXcWj8F1uqXsM4hqMSSGJdam8k96wf-zh6IzIQe2mu_cAbs41PRngyqoad-YooIGDHxjoHeOd8C3ln2UsvnoTn5r7nXwPWuORp0v-JqDpRS6b63jXNobWv9heHM542UjX5X5tD6f1vplmMRjCJm_O50XV2LrHDMG9hvQCtQGqGK7j25H18F-ftZ1KSv4G4hv9PKJ_hud7qnYXupyVo8YxcX2Aeqw-RBRi8v8njR2GvJBGNVr_gQPUC-F-TTy-lM9bBLWfZu9NuBU8z8i0--QzHuzpZNQkA-C4jkhMzabJV_D4WXjzhyPigrduND_h-Aj8S02j8NB8peksgHZOXQSFL4pIRmr2Tn0T1RpWGweQ2AbaOmgt1LK5vTveyEOCAKI0zG7bD67EFSDcH1QvwDrDSzOy7z3c8fmQblBgto0mZEknU3Pga2Vdd4xpM6R_RpMfskAU1CmJglNSF6GZPlVPrj3wAwu8_W2Eb9Ehx5WgDsoTJM0ysoyDtK0R3iC_zS8pQ3RvjLvV4T8ACfAG5SaEYMoJgwzNi1aysMKZqEU3dssHC_ZjqpT0T6kq6CNLPHxRcB7YXtQAeo0RF1lVVbhA7XL6aOL4a8eaV-bMD6lSNkMSSs4qlaKP71xKiHzMMLpLJnmjoezeevhWFQoR6V76qPoWDsy2jQlZZ-LWlikJ1X4tQeFLKdL2bZUVOOAvOiy42Yk3V5Lw_PCaYs9bj_HAUXBXl6mU_9HSTVndqty33qW_sPNWWfbUBhFudGHx6PpqP8uIdXZc9tlcUq-TjOeczcEkXlD27KiiMxPVJHs8Bbpd1le9kc2fgdKaXzmiktvOo_F7IbW0OwDOr_uul_wOssBDISejxWVxjn-_6wIy_F1R5W5jr7m-vBTQkJSls2rN4lzrqKvNrcDm0FmHg20Hd4qbb_SdRFUHWe2vWtrd1ae6yce1Rxp9RM0_C5L_TYHv8vynmvzVu3-KvEe3d5Rbj3uvjp8P23nh6pfTF41Ji-si8h8Thh7C-jd2e_BHn9hc3-L9P9G8t5fRjo2Arri0aZcRdlQRh6KiQNclyMWQ4R_e8t9Z_nggARIgyItKssojRNsMb5zKT9TsNTocxPJq_wHv5G5IcGc489MOSQRLgo7rNCGKlOc2fLdq0ASrjIf11gZAeznf7dH7FzHxQ7qHa5bxAsvGlwPFTtmg479PQZ_CwNe3AWTCvA0TiyeXgOePGEjsQbA_KyuHpY5XopRYHolwEaSHTy67nLoXLkjxegqzJGdw00HH5NcXu-O39L9f4uCGqN42RsoCkdXRptnutcFF_69WH5E5lt8oWhtPByq5ren-yFDzOCLd1lsejnEVD6ZTQmKz4b-G9yAQfO7c_K4MPiUMjBVWxbmDdv09Iqj49fH3LLtBuVnpq0a3nJBDWA0WyIytz1wL3oNlW84XGK6PsdiJx6OMpgq5ZgrirLnjeGi8LWL96_mX0DWR1_YvLXAk2lEEv_HLbaeCSAtqZUtIuRwh8VdiFoRlEUoz14tMzzIMdfYSIkbqraACPFu8s7Rsj35Tzveoep9LNAGd73qpAbvBKbA0nH0p43putZgDo5t_Kc6RLLD_S6Sv2LHHaUQWTxxZnh7lN4pVuoKalwU9x8eH-9Xxervdx8Wfy-KM3rdwIOSAzFbyg_sTc-I24DBFHeSCwMK_7PXBpdQSwVY9gof5FlRQ7E2qmemV-41bi0Vszo2O8Cd1JqXvOFmj2WNtbtm5IY6TwwWHyVKYmg0_AjqExUkBlHx-jT4FOYjvuzDTnFhaveYfMAVr4TXp8Hw0gFzIlFA2Q6bHdfYJo9r22NYa6Sxj6LZYytyrwWnFDp8dsC8xrSUT3C8v0fWrsekU1IA1uAOPLiSoI8gtiBAWd1UoLmCCkNdW1RcnPJGC1rTLWhLjU8-WMATKFwCBl8eVZiK_TPdX5KUT9E4OpFzTBCHXHxV3cRVHuf0Cm6mc5IlSZom-dXuZs6y-axMq5rSLCfRnOQzYCljOYvraMbIFb8hEUmmUZRHSZRE-XXNMlaRrKryOI1jMkNJBC3lzbUtTa6l2l65a2430-k0JelVQ0totLt8SciwqxE0u7tSN-52XNlvNUqihmujT1MYbhq48Tubu8JlY9C4-1hS4PH-fNWr5ubnb-MNSJ9uyH8FAAD__9vO8ZE">