Issue

When defining a function as inline, how to make sure that gcc will integrate its code into the code of its caller without using any of the optimisation options (-O).

#include <stdio.h>
inline int function_inline(int a, int b);

int function_inline(int a, int b) {
   return (a * b) + 3;
}

int main(int argc, char* argv[])
{
   int i = argc;
  i = function_inline(i, i+1);
  return 0;
}

Compiling the code above create the following assembly code:

$ objdump -d a.out
<output truncated>
00000000004004f6 <function_inline>:
  4004f6:       55                      push   %rbp
  4004f7:       48 89 e5                mov    %rsp,%rbp
  4004fa:       89 7d fc                mov    %edi,-0x4(%rbp)
  4004fd:       89 75 f8                mov    %esi,-0x8(%rbp)
  400500:       8b 45 fc                mov    -0x4(%rbp),%eax
  400503:       0f af 45 f8             imul   -0x8(%rbp),%eax
  400507:       83 c0 03                add    $0x3,%eax
  40050a:       5d                      pop    %rbp
  40050b:       c3                      retq   

000000000040050c <main>:
  40050c:       55                      push   %rbp
  40050d:       48 89 e5                mov    %rsp,%rbp
  400510:       48 83 ec 20             sub    $0x20,%rsp
  400514:       89 7d ec                mov    %edi,-0x14(%rbp)
  400517:       48 89 75 e0             mov    %rsi,-0x20(%rbp)
  40051b:       8b 45 ec                mov    -0x14(%rbp),%eax
  40051e:       89 45 fc                mov    %eax,-0x4(%rbp)
  400521:       8b 45 fc                mov    -0x4(%rbp),%eax
  400524:       8d 50 01                lea    0x1(%rax),%edx
  400527:       8b 45 fc                mov    -0x4(%rbp),%eax
  40052a:       89 d6                   mov    %edx,%esi
  40052c:       89 c7                   mov    %eax,%edi
  40052e:       e8 c3 ff ff ff          callq  4004f6 <function_inline>
  400533:       89 45 fc                mov    %eax,-0x4(%rbp)
  400536:       b8 00 00 00 00          mov    $0x0,%eax
  40053b:       c9                      leaveq 
  40053c:       c3                      retq   
  40053d:       0f 1f 00                nopl   (%rax)

There shouldn't be a call to function_inline() in main() but the code of the function itself.