[Bug c++/96004] New: Copy elision with conditional

[antoshkka at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96004

            Bug ID: 96004
           Summary: Copy elision with conditional
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: antoshkka at gmail dot com
  Target Milestone: ---

Consider the example:


struct Struct {
    Struct() = default;
    Struct(Struct&&);
};

Struct question10(bool b) {
    if (b) {
        Struct s{};
        return s;
    } else {
        return {};
    }
}


It is possible to elide move constructor call as the lifetimes of object `s`
and `return {}` do not intersect.

(some other compilers already do copy elision in that place
https://godbolt.org/z/wdpLkT )