https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127595
Bug ID: 127595
Summary: [ICE] internal compiler error: in verify_ctor_sanity,
at cp/constexpr.cc:7376 via brace initialization in
template
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: s103360021 at gmail dot com
Target Milestone: ---
Compiling a template function that initializes a constexpr variable using brace
initialization combined with macro-guard parentheses (e.g.,
(std::numeric_limits<size_t>::max)()) causes an internal compiler error in GCC
17. This issue was originally encountered when building the Abseil library
(absl/strings/internal/str_join_internal.h).
Godbolt link: https://godbolt.org/z/Exj8dhMzb
## Minimal Reproducible Example
```C++
// mre.cpp
#include <cstddef>
#include <cstdint>
#include <cstdlib>
#include <limits>
template <typename T>
void TriggerICE()
{
// The extra parentheses around max() prevent macro expansion,
// but combined with brace initialization in a template, it crashes GCC 17.
constexpr uint64_t kMaxSize =
uint64_t{(std::numeric_limits<std::size_t>::max)()};
// Cast to void to prevent unused variable warnings if it survives parsing
(void)kMaxSize;
}
int main()
{
TriggerICE<int>();
return EXIT_SUCCESS;
}
```
