Performance difference of "if if" vs "if else if"

Assuming simple types (in this case, I used int) and no funny business (didn't redefine operator= for int), at least with GCC 4.6 on AMD64, there is no difference. The generated code is identical:

0000000000000000 <case_1>:                                   0000000000000040 <case_2>:
   0:   85 ff                   test   %edi,%edi               40:   85 ff                   test   %edi,%edi
   2:   74 14                   je     18 <case_1+0x18>        42:   74 14                   je     58 <case_2+0x18>
   4:   83 ff 01                cmp    $0x1,%edi               44:   83 ff 01                cmp    $0x1,%edi
   7:   74 27                   je     30 <case_1+0x30>        47:   74 27                   je     70 <case_2+0x30>
   9:   83 ff 02                cmp    $0x2,%edi               49:   83 ff 02                cmp    $0x2,%edi
   c:   74 12                   je     20 <case_1+0x20>        4c:   74 12                   je     60 <case_2+0x20>
   e:   66 90                   xchg   %ax,%ax                 4e:   66 90                   xchg   %ax,%ax
  10:   f3 c3                   repz retq                      50:   f3 c3                   repz retq 
  12:   66 0f 1f 44 00 00       nopw   0x0(%rax,%rax,1)        52:   66 0f 1f 44 00 00       nopw   0x0(%rax,%rax,1)
  18:   31 c0                   xor    %eax,%eax               58:   31 c0                   xor    %eax,%eax
  1a:   e9 00 00 00 00          jmpq   1f <case_1+0x1f>        5a:   e9 00 00 00 00          jmpq   5f <case_2+0x1f>
  1f:   90                      nop                            5f:   90                      nop
  20:   31 c0                   xor    %eax,%eax               60:   31 c0                   xor    %eax,%eax
  22:   e9 00 00 00 00          jmpq   27 <case_1+0x27>        62:   e9 00 00 00 00          jmpq   67 <case_2+0x27>
  27:   66 0f 1f 84 00 00 00    nopw   0x0(%rax,%r