[Bug libstdc++/61909] New: Small function optimization not applied to small objects

[lukeocamden at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61909

            Bug ID: 61909
           Summary: Small function optimization not applied to small
                    objects
           Product: gcc
           Version: 4.10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: lukeocamden at gmail dot com

Seems like std::function only manages to avoid malloc for function pointers,
but not for small objects.

$ g++ --version
g++ (GCC) 4.10.0 20140720 (experimental)

Here's a test I ran on my Linux machine:

#include <functional>

extern "C" void* malloc(size_t) { abort(); }

struct X
{
  void operator()() { }
};

void foo() { }

int main()
{
  std::function<void()> f1((static_cast<void (*)()>([]{}))); // OK
  std::function<void()> f2(foo); // OK
  std::function<void()> f3((X())); // abort
  std::function<void()> f4([]{}); // abort
}