[clang] Crash with spaceship operator and floating-point values #170015
Description
using the following code with Clang21.1.0 and the upcoming Clang22.0.0, with the flags -std=c++23 -ffreestanding -nostdlib -fno-builtin -nostdinc -nostdinc++ causes the compiler to crash.
namespace std {
struct partial_ordering {
signed char value;
constexpr partial_ordering(signed char v) : value(v) {}
// relational operators (minimal)
constexpr bool operator==(partial_ordering other) const { return value == other.value; }
constexpr bool operator!=(partial_ordering other) const { return value != other.value; }
constexpr bool operator<(partial_ordering other) const { return value < other.value; }
constexpr bool operator>(partial_ordering other) const { return value > other.value; }
constexpr bool operator<=(partial_ordering other) const { return value <= other.value; }
constexpr bool operator>=(partial_ordering other) const { return value >= other.value; }
// static constants for convenience
static constexpr signed char less = -1;
static constexpr signed char equivalent = 0;
static constexpr signed char greater = 1;
static constexpr signed char unordered = 2;
};
}
struct compare_result {
signed char v; // -1, 0, 1, 2 for unordered
template <typename T>
constexpr compare_result(T r) {
if (r < 0) v = -1;
else if (r > 0) v = 1;
else if (r == 0) v = 0;
else v = 2; // unordered, e.g., NaN
}
constexpr bool operator==(const compare_result& o) const { return v == o.v; }
constexpr bool operator<(const compare_result& o) const { return v < o.v; }
};
int main() {
float a = 3.0f, b = 3.5f;
compare_result r = a <=> b;
int c = r.v;
}the code compiles correctly using the same flags under GCC 15.2. I've used Compiler explorer to test it. adding the -v flags produce the following results
clang version 22.0.0git (https://github.com/llvm/llvm-project.git 9bae84b01718e53495abf50958abc86ea45f16bb)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /cefs/ee/eec5d4d1d46cbdcf81dd02c6_clang-trunk-20251129/bin
Found candidate GCC installation: /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/16.0.0
Selected GCC installation: /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/16.0.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
(in-process)
"/cefs/ee/eec5d4d1d46cbdcf81dd02c6_clang-trunk-20251129/bin/clang-22" -cc1 -triple x86_64-unknown-linux-gnu -S -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name example.cpp -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=all -fmath-errno -ffp-contract=on -fno-rounding-math -fno-verbose-asm -mconstructor-aliases -ffreestanding -target-cpu x86-64 -tune-cpu generic -debug-info-kind=constructor -dwarf-version=5 -debugger-tuning=gdb -fdebug-compilation-dir=/app -v -fcoverage-compilation-dir=/app -nostdsysteminc -nobuiltininc -resource-dir /cefs/ee/eec5d4d1d46cbdcf81dd02c6_clang-trunk-20251129/lib/clang/22 -std=c++23 -fdeprecated-macro -ferror-limit 19 -fno-builtin -fgnuc-version=4.2.1 -fno-implicit-modules -fskip-odr-check-in-gmf -fcxx-exceptions -fexceptions -fcolor-diagnostics -faddrsig -fdwarf2-cfi-asm -o /app/output.s -x c++ <source>
clang -cc1 version 22.0.0git based upon LLVM 22.0.0git default target x86_64-unknown-linux-gnu
#include "..." search starts here:
End of search list.
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++ -g -o /app/output.s -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -std=c++23 -ffreestanding -nostdlib -fno-builtin -nostdinc -nostdinc++ -v <source>
1. <source>:41:31: current parser token ';'
2. <source>:39:12: parsing function body 'main'
3. <source>:39:12: in compound statement ('{}')
#0 0x0000000003cd7358 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3cd7358)
#1 0x0000000003cd4d2c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3cd4d2c)
#2 0x0000000003c1ac38 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
#3 0x0000786daa842520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
#4 0x0000000007294195 clang::RecordDecl::field_begin() const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x7294195)
#5 0x0000000007272aa2 clang::ComparisonCategoryInfo::ValueInfo::hasValidIntValue() const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x7272aa2)
#6 0x000000000665f2e6 clang::Sema::CheckComparisonCategoryType(clang::ComparisonCategoryType, clang::SourceLocation, clang::Sema::ComparisonCategoryUsage) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x665f2e6)
#7 0x0000000006768cb7 clang::Sema::CheckCompareOperands(clang::ActionResult<clang::Expr*, true>&, clang::ActionResult<clang::Expr*, true>&, clang::SourceLocation, clang::BinaryOperatorKind) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x6768cb7)
#8 0x000000000676a294 clang::Sema::CreateBuiltinBinOp(clang::SourceLocation, clang::BinaryOperatorKind, clang::Expr*, clang::Expr*, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x676a294)
#9 0x000000000676b760 clang::Sema::BuildBinOp(clang::Scope*, clang::SourceLocation, clang::BinaryOperatorKind, clang::Expr*, clang::Expr*, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x676b760)
#10 0x000000000676bb3c clang::Sema::ActOnBinOp(clang::Scope*, clang::SourceLocation, clang::tok::TokenKind, clang::Expr*, clang::Expr*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x676bb3c)
#11 0x0000000006265bfc clang::Parser::ParseRHSOfBinaryExpression(clang::ActionResult<clang::Expr*, true>, clang::prec::Level) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x6265bfc)
#12 0x0000000006290a70 clang::Parser::ParseInitializer(clang::Decl*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x6290a70)
#13 0x000000000621d855 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x621d855)
#14 0x0000000006231ffc clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x6231ffc)
#15 0x0000000006234a0c clang::Parser::ParseSimpleDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, bool, clang::Parser::ForRangeInit*, clang::SourceLocation*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x6234a0c)
#16 0x0000000006234e5a clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x6234e5a)
#17 0x00000000062f15df clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 24u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::LabelDecl*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x62f15df)
#18 0x00000000062f1f26 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 24u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::LabelDecl*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x62f1f26)
#19 0x00000000062fb419 clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x62fb419)
#20 0x00000000062fbeba clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x62fbeba)
#21 0x00000000061e5b4b clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x61e5b4b)
#22 0x000000000623245f clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x623245f)
#23 0x00000000061def8f clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x61def8f)
#24 0x00000000061df6c7 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x61df6c7)
#25 0x00000000061e809f clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x61e809f)
#26 0x00000000061e98a7 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x61e98a7)
#27 0x00000000061c277a clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x61c277a)
#28 0x0000000004595f65 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4595f65)
#29 0x000000000489760a clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x489760a)
#30 0x00000000048164eb clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x48164eb)
#31 0x000000000498c14b clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x498c14b)
#32 0x0000000000dce015 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xdce015)
#33 0x0000000000dc5ecb ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>) driver.cpp:0:0
#34 0x0000000000dc5f6d int llvm::function_ref<int (llvm::SmallVectorImpl<char const*>&)>::callback_fn<clang_main(int, char**, llvm::ToolContext const&)::'lambda'(llvm::SmallVectorImpl<char const*>&)>(long, llvm::SmallVectorImpl<char const*>&) driver.cpp:0:0
#35 0x0000000004603299 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
#36 0x0000000003c1b053 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3c1b053)
#37 0x00000000046034b9 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
#38 0x00000000045c5e42 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x45c5e42)
#39 0x00000000045c6d21 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+++0x45c6d21)
#40 0x00000000045cf90c clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x45cf90c)
#41 0x0000000000dca999 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xdca999)
#42 0x0000000000c74c84 main (/opt/compiler-explorer/clang-trunk/bin/clang+++0xc74c84)
#43 0x0000786daa829d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#44 0x0000786daa829e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#45 0x0000000000dc5965 _start (/opt/compiler-explorer/clang-trunk/bin/clang+++0xdc5965)
clang++: error: clang frontend command failed with exit code 139 (use -v to see invocation)
Compiler returned: 139