[SOLVED] Which if statement would execute faster?

Which if statement would execute faster?

Let's say the we have an object and that we need to validate the following things -

Object->text length is greater than 0
Object->dummy is not null
Objecct->dummy2 exists in another object

We have two possibilities for a if statement:

if(greaterThan(Object->text, 0) && 
   exists(Objet->dummy) && 
   inObject(Object->dummy2, Objet2))

Second if:

if(!greaterThan(Object->text, 0) || 
       !exists(Objet->dummy) || 
       !inObject(Object->dummy2, Objet2)) {
  NOP  
 } else {
   //Do something;
}

Which one would be faster? Thanks in advance.

Solution

In general, those two forms are equivalent and a decent compiler would likely compile them to the same final assembly. You should check on your specific compiler, of course. You can take a look at the assembly output of a few compilers here for your problem

For example, the gcc 4.9 output:

void function1() {
  if (greaterThan() &&  exists() && inObject()) {
    result = 42;
  }
}

gives:

function1():
    sub rsp, 8
    call    greaterThan()
    test    eax, eax
    jne .L13
.L1:
    add rsp, 8
    ret
.L13:
    call    exists()
    test    eax, eax
    je  .L1
    call    inObject()
    test    eax, eax
    je  .L1
    mov DWORD PTR result[rip], 42
    jmp .L1

while, the other variant:

void function2() {
  if (!greaterThan() ||  !exists() || !inObject()) {
    // NOP
  } else {
    result = 42;
  }
}

leads to identical assembly:

function2():
    sub rsp, 8
    call    greaterThan()
    test    eax, eax
    jne .L28
.L14:
    add rsp, 8
    ret
.L28:
    call    exists()
    test    eax, eax
    je  .L14
    call    inObject()
    test    eax, eax
    je  .L14
    mov DWORD PTR result[rip], 42
    jmp .L14

In all cases the compilers produced identical assembly for both options (I simplified it slightly by removing some arguments, but that should be immaterial).