LTO gcc test

a.cpp

#include "a.hpp"
#include "stdio.h"

void A::set(int a, int b)
{
	x = a;
	y = b;
}
void A::get()
{
	printf("%d %d\n", x, y);
}

a.hpp

class A {
private:
  int x, y;
public:
  void set(int a, int b);
  void get();
};

test.cpp

#include "a.hpp"

int main()
{
  A a;
  a.set(10, 15);
  a.get();
}

test.sh

g++ -c -O2 -flto -g test.cpp a.cpp && g++ -O2 -g test.o a.o
objdump -S a.out | grep 'int main' -A15

# Optimized output:
# 
# int main()
# {
#   400550:	48 83 ec 08          	sub    $0x8,%rsp
# 	x = a;
# 	y = b;
# }
# void A::get()
# {
# 	printf("%d %d\n", x, y);
#   400554:	ba 0f 00 00 00       	mov    $0xf,%edx
#   400559:	be 0a 00 00 00       	mov    $0xa,%esi
#   40055e:	bf 04 07 40 00       	mov    $0x400704,%edi
#   400563:	31 c0                	xor    %eax,%eax
#   400565:	e8 b6 ff ff ff       	callq  400520 <printf@plt>
#   A a;
#   a.set(10,15);