<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/132023>132023</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Use of wrong-architecture inline assembly with `-fopenmp` turns diagnostic into crash
        </td>
    </tr>

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

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

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

<pre>
    When porting a project which originally targeted _X86-64_ to _ARM64_ (MacOS), I've come across a crash which I was able to reduce to the following.

```c
#include <stdlib.h>

__inline__ uint64_t rdtsc() {
   uint32_t lo, hi;
   __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
   return (uint64_t)hi << 32 | lo;
}

int main(void) {
   rdtsc();
}
```

The code is diagnosed in normal compilation mode:

```
❯ ./clang --target=arm64-apple-darwin24.3.0 -c ./temp.c

./temp.c:5:36: error: invalid output constraint '=a' in asm
    5 |    __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
      |                                    ^
1 error generated.
```

But crashes with `-fopenmp`:

```
❯ ./clang --target=arm64-apple-darwin24.3.0 -c ./temp.c -fopenmp
Assertion failed: (IsValid && "Failed to parse output constraint"), function EmitAsmStmt, file CGStmt.cpp, line 2747.

Stack dump:
0.      Program arguments: ./clang --target=arm64-apple-darwin24.3.0 -c ./temp.c -fopenmp 
1.      <eof> parser at end of file
2.      Per-file LLVM IR generation
3.      ./temp.c:3:21: Generating code for declaration 'rdtsc'
 #0 0x00000001041c310c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int)
 #1 0x00000001041c11d0 llvm::sys::RunSignalHandlers()
 #2 0x00000001041c26c0 llvm::sys::CleanupOnSignal(unsigned long)
 #3 0x0000000104117b7c CrashRecoverySignalHandler(int)
 #4 0x0000000188386de4 (/usr/lib/system/libsystem_platform.dylib)
 #5 0x000000018834ff70 (/usr/lib/system/libsystem_pthread.dylib)
 #6 0x000000018825c908 (/usr/lib/system/libsystem_c.dylib)
 #7 0x000000018825bc1c (/usr/lib/system/libsystem_c.dylib)
 #8 0x0000000106d4a59c clang::CodeGen::CodeGenFunction::EmitBreakStmt(clang::BreakStmt const&) (.cold.1)
 #9 0x000000010497cd18 clang::CodeGen::CodeGenFunction::EmitAsmStmt(clang::AsmStmt const&)
#10 0x000000010497ecbc clang::CodeGen::CodeGenFunction::EmitCompoundStmtWithoutScope(clang::CompoundStmt const&, bool, clang::CodeGen::AggValueSlot)
#11 0x00000001049da200 clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&)
#12 0x00000001049fc79c clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*)
#13 0x00000001049f564c clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*)
#14 0x00000001049e8b70 clang::CodeGen::CodeGenModule::EmitDeferred()
#15 0x00000001049e8b98 clang::CodeGen::CodeGenModule::EmitDeferred()
#16 0x00000001049e63e0 clang::CodeGen::CodeGenModule::Release()
#17 0x0000000104a7d404 (anonymous namespace)::CodeGeneratorImpl::HandleTranslationUnit(clang::ASTContext&)
#18 0x00000001049cb944 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&)
#19 0x0000000105845fac clang::ParseAST(clang::Sema&, bool, bool)
#20 0x0000000104cf4080 clang::FrontendAction::Execute()
#21 0x0000000104c8a870 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&)
#22 0x0000000104d6e9a0 clang::ExecuteCompilerInvocation(clang::CompilerInstance*)
#23 0x0000000102cb76c0 cc1_main(llvm::ArrayRef<char const*>, char const*, void*)
#24 0x0000000102cb4d88 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&)
#25 0x0000000104b01ab0 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::__1::optional<llvm::StringRef>>, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>*, bool*) const::$_0>(long)
#26 0x0000000104117888 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>)
#27 0x0000000104b01514 clang::driver::CC1Command::Execute(llvm::ArrayRef<std::__1::optional<llvm::StringRef>>, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>*, bool*) const
#28 0x0000000104ad11a8 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const
#29 0x0000000104ad1370 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::__1::pair<int, clang::driver::Command const*>>&, bool) const
#30 0x0000000104ae85a8 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::__1::pair<int, clang::driver::Command const*>>&)
#31 0x0000000102cb41cc clang_main(int, char**, llvm::ToolContext const&)
#32 0x0000000102cbfca4 main
#33 0x0000000187fd0274
clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
clang version 21.0.0git
Target: arm64-apple-darwin24.3.0
Thread model: posix
Build config: +assertions, +expensive-checks
```

commit 861efd4b3f93d30d353f0a6eea249fbdac1778a0
</pre>
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