Optimization Impact: ⭐️⭐️⚪⚪⚪
CRTP is a design pattern where the base class takes in derived class as a template parameter. This way, no virtual function is created, no runtime cost is spent on vtable look up, and static polymorphism is achieved.
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template <typename Derived>
class Addable {
Derived operator+(const Derived& other) const {
return Derived(static_cast<const Derived*>(this)->get() + other.get());
}
};
class MyInt : public Addable<MyInt> {
int value;
public:
MyInt(int v) : value(v) {}
int get() const { return value; }
};
class MyFloat : public Addable<MyInt> {
float value;
public:
MyFloat(int v) : value(v) {}
int get() const { return value; }
};
For more benchmarking, please check this code snippet and try yourself!. Without any optimization, CRTP is 103ms, while runtime polymorphism is 170ms. But with -O3 optimization, both are 0ms. So the optimization effect is limited.
