[Bug tree-optimization/118830] New: Not removing bounds check from vector::at if used with try/catch (which recovers inside the loop)

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118830

            Bug ID: 118830
           Summary: Not removing bounds check from vector::at if used with
                    try/catch (which recovers inside the loop)
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

Take:
```
#include <vector>

std::vector<int> vector_init() {
    std::vector<int> v(10'000);
    for(int i = 0; i < 10'000; ++i) {
#ifndef WO_TRY
        try {
#endif
            v.at(i) = i;
#ifndef WO_TRY
        } catch(...) {}
#endif
    }
    return v;
}
```

We can optimize this with -DWO_TRY at -O2 but without, there is still bounds
check inside the loop even though the bounds check is not reachable.