https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71913
Bug ID: 71913
Summary: [5/6/7 Regression] Missing RVO for operator new
Product: gcc
Version: 6.1.0
Status: UNCONFIRMED
Keywords: missed-optimization, wrong-code
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
void* operator new(unsigned long, void* p) { return p; }
void always_assert(bool);
struct IndirectReturn {
IndirectReturn() {}
// Make sure the indirect return value is never copied and RVO kicked in
IndirectReturn(const IndirectReturn&) { always_assert(false); }
IndirectReturn& operator=(const IndirectReturn&) = delete;
~IndirectReturn() {}
};
IndirectReturn foo();
void bar(void* ptr) {
IndirectReturn x;
new (ptr) IndirectReturn(foo());
}
---- CUT -----
In GCC 4.9.3 we did not get the assert but in 5.x and above we do.
This causes HHVM to crash some of the time.
Note if I read C++17 correctly this is a required to get rid of the copy
constructor here.
