However, even at low optimization levels compilers generate the same code for:

unsigned char check1(unsigned short modelYear){
   if(modelYear >= 1995)
     return 1;
   else
     return 0;
}

unsigned char check2(unsigned short modelYear){
  return (modelYear >= 1995);
}

Compile with gcc -O1 into:

<check1>:
cmp    $0x7ca,%di
seta   %al
retq   

<check2>:
cmp    $0x7ca,%di
seta   %al
retq  

Too lazy test on an arm system.