https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114858
Bug ID: 114858
Summary: Compilation Hang and Excessive RAM Consumption in GCC
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: iamanonymous.cs at gmail dot com
Target Milestone: ---
The following code snippet triggers a hang issue:
============================================
$ cat bug.cpp
template <class F> void g(F);
template <class... A>
auto h(A &&... a) -> decltype(g(0,
(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype(g<decltype()>)(a)...))
{
h([] {});
}
int main() {
h();
return 0;
}
============================================
I observed that when attempting to compile this code using GCC, the compilation
process hangs indefinitely, without providing any output or indicating
successful compilation. Additionally, the RAM usage continuously increases,
leading to excessive consumption of system resources.
However, it is worth noting that when using LLVM as the compiler, the code
compiles quickly and produces the expected compilation output.
We have found that this issue still persists in the latest version of GCC(see
https://godbolt.org/z/P1c7f664f)
The command we used is(no error output):
============================================
g++ bug.cpp
============================================
The GCC version:
============================================
$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/home/cTest/gcc/myinstall/libexec/gcc/x86_64-linux-gnu/14.0.1/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../configure -v --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu --enable-checking=no
--enable-languages=c,c++ --disable-multilib --prefix=/home/cTest/gcc/myinstall
--disable-bootstrap
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.1 20240329 (experimental) (GCC)
============================================
