Code Optimizations

My obsession with trying to build a kernel , led me to stumble on bad coding practices which cripple at scale.

[Ref. book Computer Systems - A Programmers Perspective]

1. Using function to check end of loop

    while(i<check_condition()){
    //do something
    }   

It is expected that the compiler optimizes by running the check_condition() only once.Storing it at some temporary location . But a look at the assembly code .Shows repeated calls to the check_condition

```.L6:
	subl	$1, -4(%rbp)
.L5:
	movl	-4(%rbp), %eax
	movl	%eax, %edi
	call	check
	testb	%al, %al
	jne	.L6
	leave
	```

1. A similar reason can be found while referencing arrays in loops.

   while(){
       a[0]++;
   }
   

   should be written as .

   ```
   while(){
       temp++
   }
   a[0]=temp
   ```         This would decrease atleast 4 assembly instructions .