Open
Description
Full stacktrace, only works in c++26 mode with a very large -fconstexpr-step= limit.
0. Program arguments: /opt/compiler-explorer/clang-trunk-20250426/bin/clang-21 -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -dumpdir /app/output.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 -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debug-info-kind=constructor -dwarf-version=4 -debugger-tuning=gdb -fdebug-compilation-dir=/app -fcoverage-compilation-dir=/app -resource-dir /opt/compiler-explorer/clang-trunk-20250426/lib/clang/21 -isystem /opt/compiler-explorer/libs/fmt/trunk/include -internal-isystem /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/16.0.0/../../../../include/c++/16.0.0 -internal-isystem /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/16.0.0/../../../../include/c++/16.0.0/x86_64-linux-gnu -internal-isystem /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/16.0.0/../../../../include/c++/16.0.0/backward -internal-isystem /opt/compiler-explorer/clang-trunk-20250426/lib/clang/21/include -internal-isystem /usr/local/include -internal-isystem /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/16.0.0/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -std=c++26 -fdeprecated-macro -fconstexpr-steps=99999999 -ferror-limit 19 -fgnuc-version=4.2.1 -fno-implicit-modules -fskip-odr-check-in-gmf -fcxx-exceptions -fexceptions -fcolor-diagnostics -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/example-456c4d.o -x c++ <source>
1. <eof> parser at end of file
2. <source>:28:1: LLVM IR generation of declaration
#0 0x0000000003bd83d8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk-20250426/bin/clang-21+0x3bd83d8)
#1 0x0000000003bd5f94 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
#2 0x000074c8b2242520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
#3 0x000074c8b23a0d30 (/lib/x86_64-linux-gnu/libc.so.6+0x1a0d30)
#4 0x000074c8b274c104 std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>::_M_mutate(unsigned long, unsigned long, char const*, unsigned long) (/lib/x86_64-linux-gnu/libstdc++.so.6+0x14c104)
#5 0x000074c8b274db50 std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>::_M_append(char const*, unsigned long) (/lib/x86_64-linux-gnu/libstdc++.so.6+0x14db50)
#6 0x000000000415ad50 clang::CodeGen::CodeGenModule::EmitTopLevelDecl(clang::Decl*) (.part.0) CodeGenModule.cpp:0:0
#7 0x000000000451650e (anonymous namespace)::CodeGeneratorImpl::HandleTopLevelDecl(clang::DeclGroupRef) ModuleBuilder.cpp:0:0
#8 0x0000000004500389 clang::BackendConsumer::HandleTopLevelDecl(clang::DeclGroupRef) (/opt/compiler-explorer/clang-trunk-20250426/bin/clang-21+0x4500389)
#9 0x0000000006147584 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-trunk-20250426/bin/clang-21+0x6147584)
#10 0x0000000004513b2d clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-trunk-20250426/bin/clang-21+0x4513b2d)
#11 0x000000000482266a clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-trunk-20250426/bin/clang-21+0x482266a)
#12 0x000000000479eaab clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-trunk-20250426/bin/clang-21+0x479eaab)
#13 0x0000000004912773 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-trunk-20250426/bin/clang-21+0x4912773)
#14 0x0000000000db4311 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-trunk-20250426/bin/clang-21+0xdb4311)
#15 0x0000000000dac4bd ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#16 0x0000000000daf310 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-trunk-20250426/bin/clang-21+0xdaf310)
#17 0x0000000000c325a4 main (/opt/compiler-explorer/clang-trunk-20250426/bin/clang-21+0xc325a4)
#18 0x000074c8b2229d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#19 0x000074c8b2229e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#20 0x0000000000dabf55 _start (/opt/compiler-explorer/clang-trunk-20250426/bin/clang-21+0xdabf55)
clang++: error: unable to execute command: Segmentation fault (core dumped)
clang++: error: clang frontend command failed due to signal (use -v to see invocation)
Source
#include <string>
#include <format>
#include <fmt/format.h>
#include <fmt/compile.h>
consteval std::string GenerateIsrTable() {
std::string isrs;
isrs.reserve(0x10000);
for (size_t i = 32; i < 34; i++) {
fmt::format_to(
std::back_inserter(isrs),
FMT_COMPILE(
".align 16\n"
"AsmIsr{0}:\n"
" pushq {0}\n"
" pushq {0}\n"
" jmp AsmIsrEntry\n")
, i);
}
return isrs;
}
asm(
"AsmIsrEntry:\n"
"nop\n"
);
asm((GenerateIsrTable()));