[Bug c++/58116] New: missed-optimization: const temporaries could be promoted to static

[luto at mit dot edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58116

            Bug ID: 58116
           Summary: missed-optimization: const temporaries could be
                    promoted to static
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: luto at mit dot edu

This code:

struct S
{
  int a, b, c;
};

extern void callee(const S &s);

void test()
{
  const S s{1,2,3};
  callee(s);

  callee((const S){1,2,3});
}

would be shorter and faster if both S instances were promoted to statics.  This
would be correct because it's undefined behavior to modify a non-mutable member
of an object declared const in C++.  (I'm not sure about C.)