<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/113211>113211</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/GYhd9EeG4
```console
fatal error: error in backend: Stack empty??
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-19.1.0/bin/clang -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-13.2.0 -fcolor-diagnostics -fno-crash-diagnostics -fsanitize=undefined -fsanitize=address -O0 <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 '@____strtold_l_internal'
 #0 0x00000000036fdb08 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x36fdb08)
 #1 0x00000000036fbc74 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x36fbc74)
 #2 0x0000000003648113 llvm::CrashRecoveryContext::HandleExit(int) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x3648113)
 #3 0x00000000036f344e llvm::sys::Process::Exit(int, bool) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x36f344e)
 #4 0x0000000000c855c6 (/opt/compiler-explorer/clang-19.1.0/bin/clang+0xc855c6)
 #5 0x0000000003652143 llvm::report_fatal_error(llvm::Twine const&, bool) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x3652143)
 #6 0x00000000036522a8 (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x36522a8)
 #7 0x00000000022f8ca7 (anonymous namespace)::FPS::processBasicBlock(llvm::MachineFunction&, llvm::MachineBasicBlock&) (.isra.0) X86FloatingPoint.cpp:0:0
 #8 0x00000000022f926e (anonymous namespace)::FPS::runOnMachineFunction(llvm::MachineFunction&) (.part.0) X86FloatingPoint.cpp:0:0
 #9 0x00000000022f9abb (anonymous namespace)::FPS::runOnMachineFunction(llvm::MachineFunction&) X86FloatingPoint.cpp:0:0
#10 0x0000000002b5181b llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
#11 0x000000000309ca72 llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x309ca72)
#12 0x000000000309cbf1 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x309cbf1)
#13 0x000000000309e8a0 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x309e8a0)
#14 0x0000000003996531 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-19.1.0/bin/clang+0x3996531)
#15 0x0000000003fce094 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x3fce094)
#16 0x0000000005f1899c clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x5f1899c)
#17 0x0000000003fce825 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x3fce825)
#18 0x0000000004274201 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x4274201)
#19 0x00000000041f699b clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x41f699b)
#20 0x000000000435a843 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x435a843)
#21 0x0000000000c874dc cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0xc874dc)
#22 0x0000000000c8146d ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#23 0x0000000004017309 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
#24 0x0000000003648013 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x3648013)
#25 0x0000000004017529 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
#26 0x0000000003fdd947 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x3fdd947)
#27 0x0000000003fde2fd clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x3fde2fd)
#28 0x0000000003fe7d4c clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0x3fe7d4c)
#29 0x0000000000c847f1 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-19.1.0/bin/clang+0xc847f1)
#30 0x0000000000b5c2d4 main (/opt/compiler-explorer/clang-19.1.0/bin/clang+0xb5c2d4)
#31 0x000070d58e029d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#32 0x000070d58e029e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#33 0x0000000000c80f0e _start (/opt/compiler-explorer/clang-19.1.0/bin/clang+0xc80f0e)
clang: error: clang frontend command failed with exit code 70 (use -v to see invocation)
Compiler returned: 70
```
```c
#include <stdio.h>
#include <stdlib.h>

long double ____strtold_l_internal___x;

void ____strtold_l_internal() {
 __asm__("" : "+fm"(____strtold_l_internal___x));
    printf("Variable ____strtold_l_internal___x: %Lf\n", ____strtold_l_internal___x);
}

int main() {
 ____strtold_l_internal___x = 1.41421;
    ____strtold_l_internal();
 return 0;
}
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzkWk1zo7jW_jVko7ILBBhYZOE48XxUT3WqnXdq3hUlxMHWbZC4kkg78-tvSYCNiJP0THvu5nalE0cf5zzn0fkChSjF9hzg1ovvvPj-hnT6IORtwVb0phDly-1GNC2rQaKHY1sLCdIL1-igdau8cO3hrYe3e1EWotZLIfce3v7p4e1P_38oswf4KfL8e89feyu__6KCK1FDP1oRTWoEUgor035AjKOC0K_ASzO204R-RdC0-sULt-bL7nz89LDePSDVFQ3TiKCi2yMJrZAaaTEHx_ShK5ZUNB7e1vXz-GPRSvEvoNrDW6ZUB8rDW0R4iRindVcC0gdAVBJ1sIC0JBQ8vEGthFYKCkpBiZToZD9sdhKlBGVEQ4lkx5GikrV62UPuLSm7pjXI7JC_9PzsUYq9JA0ict81wLUBjjy8Fa1BRgfyFzCSj7e0Jny_CLJlsPQ9vC0YHwfRYl9-I7JaRGixRwth5JC2NdI63XZ6qdCiMbajxeKYrhZENQv1wjU5euE94xpqtKi4WDyDLIQCM48WO7RY7CldaCFqeiCMe-H9u_jM4iBc4qWPFhUVtZCLkpE9F0ozqnoNltfZsCKcafYneOF9x0uoGIfSHSZlKUEptPjsIy_cDOSHDz2dgaHTCzcgKi98QC2RCiQiGgEvkahQxUbHw2blRpSA9sBBEs0E72dCM_Ol45zxPWqJUsjDybbj1CxBj2bgN8LJ3hiaIMFRI8quBrPKAYST4dijSwL_SFdo-9g7N6vYSVg1KjLiIj_P81xpqUVd5nVuzkdyUps5Kxp5OPSRf_THf-GqKgs_RdbJw7UXrtWL6j88Ssa11ffU-3F6XiTJt1woLYE0Hl4ZX2ZcezhDHk7_piN6-M4_DnA8nJ3xBjO8BU2iS3g3NRDetZ_5ju2tzWnHbZ4qUS2M_GugM8oddNhFF6VBEE7QbYzTfgEqnkG-bATXcNT9zM-ElzU8HJn2cHot9qx6B184Yy-MIrh82jY_9b9MUW1QIUR9HfaMcgddNEXn0zSO6epH9fRSHDWxS0KMg2h6SH0ZyG1tyfvaMnX2p2-MAzJlSA_OfjVGLBIH6moOFZP0GnowcaMqmerBuEopSYwewgV_aUSnECcNqNZGftYTsX3c9R-GYnZHFKN3taBfHb5-I_TAOIwpcODs1fx092pgc8mUJMaGDP2Rrra1IJrx_aNgXC9pa8qgb_-fzEhnZmR4Bd9thuz4Z_4K7QeW9DhbIvVfwZnNcZKi-KdxfozMZFenHOAiDtKgeH1Yo2hTziagLqJ5l64L8i7jctO-n1GS4Amu7aPZOhbWv4zoh8KpB3MKJ4MWz9EWVfAdaH-zrYB7lsPQtZAWVeAgDWdIISX-BGkNe0JfhppwxvxL09Yn3P8kXgPHweuUiDDLVnEYoH5LX6sapu_67v-z7Vg9nE6m78_94gPfMw5DOpos-RlICXIHRNLD59b4iXKy_WSpaQB_Av7Bqici96A_WPSJ8P2lJWdmd1oyvv8C1Sx9DoSvZwIHEtaDp0-3_MK17BR7hi9Qbbh-1NILN-fp52qI6S2rYfeiNDS2Id0gpct-puPs3x3k7Wyn6QPbb5JpyMducLKphIp0tc5LqEHDBxvDh0Hna5M2gquuMQ60voaT9T7kOJnbIFQU_Cx6D8ikg3uShKvaPg_8H2cz71vvnsam7zoB0kNzsDsdQ1wFaZbRKfZH81Cz3j25yHbQEKebuVpXM0BwMCZzflMcX4irwXeHHhRop2F05_RK7KU4dpA5DUSEkwj7TnrZSnN-p7CaQrsOqEGnA8rpFqKgWmVZ4dLVq_mFK024eXy8xNjbVlzFFwdcU-DYaSaiMCZpFDrJuod4xv8sKHkN95V9Vwn8AY8DOJg9gCRRSRGlQd4Q5ta5tZTkxSTjcEMPRI45ez1mLWcMb9CzYOV1cPeoHNh4BjuIViUayd0ETzaSJ-B3Danr34FqMVTyCzbMqo-RMeSuSX3KUCnZM8iLPRt2eovID5LQzywRE7njC4tcWi7tbB9JtgSYJZTUdUHo17ziBunZL3rdg49sgo1oGsLLeVBePLNTURK25pLaKUfnUnsqQ6cNeU6PxyDofynMQ4spWcxgsiw6i81AriVhWo3TM3Gkro3PCzmZN0vW5xRsnabn3G7xcFKTpiiJh5MzVTgdX2v8KorL5xHNX0743_ly4kvHd6SC-sWh8_2ju877Cz9wAzSeu1RsuPkfdonZ89SbZ---SKjKMouSN4mzZ0VeVbiRTSc5zzaaBW_1uO8sXc9epZxs-7ECb810HGjWepSAq_Kv8vCrKNTbJPwqik9M6be6-Fep93TuLWHmyIfXbN_L2-Ac_wh7hhyHvdRlD5Iyom8hvZ98dgr9hQr_Fuv_Rfau0E5aOhy-sllhjpJqaCfHjmLEa9PEegjyj8vuD_cQBskUqnsP4BcxxWWEDMgf1dWLcnSNbVbil3EKPs7KzB_U1Kzw8PaYrvJVtKgZ746LPe_6CbpUYrmyQu0WRyaey4TIR3lutuVKE6nziTHfrQUiV0s4O1C_8gH18n_8TIywk7bRg8-3m_0FXTX07ogOvlwRVkOJvjF9QHBkxk9KQIkltFOAFs9IC6QAEJv014OW09WsBN1JDvbKNPFnd67zK9gTH-NFZx-ITCwPp7u0V7M1K6bT9rtpWVApuqIGdPmuKs_zoxfeTTfZRuOtm63-GSwZNqA8J6rJczuOPYxRfzeKPXxXNfZn-o5enNlmZhSGEGol47rqxf1OJCMfITfa4k-VF2-4Vbd5b_VEmZfcT21mXKMhY8wNfEsa8sJ7FCyjIMKBY8N71J0X9g6B_AuIRj-4KW_DMgszcgO3QYKzOPKTML453CYFKaugCEgBPqYxVBmFKitDUuAYyiy6YbfYx1Hg4yDI4jSOl5G_8iGIi6Tyqyqh1It8aAirlyYVLoXc39gb9tsgCHEQ3NSkgFrZPzjAeAgh7MX3N_LWXswX3V55kV8zpdVZhGa6hts-jOz1MShEtL0LFhzNs8FNJ-vbv_-HAAPS51v8nwAAAP__6Rb1tg">