https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98930
Bug ID: 98930
Summary: ICE when using function local static constexpr
variable at runtime
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: matthieum.147192 at gmail dot com
Target Milestone: ---
The following code crashes gcc trunk (11.0) and produces a linker error on
prior versions -- from 7.2 to 10.2.1 -- from -O0 to -O3.
Link to compiler explorer: https://godbolt.org/z/qox73Y
Self-sufficient code snippet:
template <char const* format>
class Source {
public:
explicit Source() noexcept {
asm volatile("" : : "r,m"(format) : "memory");
}
int index() const noexcept { return 0; }
};
template <typename T>
T impl() {
static constexpr const char FORMAT_[] = "Hello, {}!";
static Source<FORMAT_> const SOURCE{};
return SOURCE.index();
}
int main() {
return impl<int>();
}
GCC trunk crash:
<source>: In instantiation of 'Source<format>::Source() [with const char*
format = (& FORMAT_)]':
<source>:4:14: required from here
<source>:4:14: internal compiler error: in discriminator_for_local_entity, at
cp/mangle.c:1949
4 | explicit Source() noexcept {
| ^~~~~~
0x1ce5ce9 internal_error(char const*, ...)
???:0
0x6b6f1b fancy_abort(char const*, int, char const*)
???:0
0x812f3b mangle_decl(tree_node*)
???:0
0x135b052 decl_assembler_name(tree_node*)
???:0
0x138e478 assign_assembler_name_if_needed(tree_node*)
???:0
0xb48015 cgraph_node::analyze()
???:0
0xb4c6dd symbol_table::finalize_compilation_unit()
???:0
GCC 10.2 linker error:
/opt/compiler-explorer/gcc-10.2.0/bin/../lib/gcc/x86_64-linux-gnu/10.2.0/../../../../x86_64-linux-gnu/bin/ld:
/tmp/cc6YCcxH.o: in function `_ZN6SourceIXadL_ZZ4implIT_ES1_vE7FORMAT_EEEC1Ev':
/home/ce/<source>:5: undefined reference to `_ZZ4implIT_ES0_vE7FORMAT_'
collect2: error: ld returned 1 exit status
Other compilers: ICE on Clang 11.0, Works on Clang (trunk).
In the same area (local static constexpr) I found 2 bug reports:
- https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95686
- https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98288 (which I reported)
Regards.
