| Summary: | Out of bounds pointer arithmetic for dynamic allocated arrays not caught in constexpr | ||
|---|---|---|---|
| Product: | gcc | Reporter: | Jeremy R. <llvm> |
| Component: | c++ | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | NEW --- | ||
| Severity: | normal | CC: | daniel.kruegler, mpolacek, webrown.cpp |
| Priority: | P3 | Keywords: | accepts-invalid |
| Version: | unknown | ||
| Target Milestone: | --- | ||
| See Also: | https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97230 | ||
| Host: | Target: | ||
| Build: | Known to work: | ||
| Known to fail: | Last reconfirmed: | 2023-08-30 00:00:00 | |
| Bug Depends on: | |||
| Bug Blocks: | 55004 | ||
Confirmed reduced testcase:
```
#define size 3
constexpr auto tester() {
int *v = new int[size];
auto p = &v[size+1];
bool t = &v[0] == p;
delete[] v;
return t;
}
static_assert(!tester());
#if 0
constexpr auto tester1() {
int v[size];
auto p = &v[size+1];
bool t = &v[0] == p;
return t;
}
static_assert(!tester1());
#endif
```
GCC does catch the static allocated one; just not the dynamic allocated one.
. |
The following UB is not caught by gcc: #include <vector> constexpr auto tester() { std::vector<int> v = {1, 2, 3}; auto p = &v[v.size() + 1]; return &v[0] == p; } static_assert(!tester()); https://godbolt.org/z/Y3ofcb1b1