LLVM does not care about your C optimizations

objc-pre-post-loops.asm

## for (int i = 0; i < 10; i++) { }

LBL1:
  cmpl  $10, -4(%ebp)             ## -4(%ebp) is the stack address of i. Check if it is less than 10
  jge LBL3                        ## If the previous compare had a greater than or equal to result, exit the loop
  jmp LBL2                        ## Otherwise, jump to the next address (this instruction will get optimized away)
LBL2:
  movl  -4(%ebp), %eax            ## Load i into the EAX register (where the arithmetic happens!)
  addl  $1, %eax                  ## Add 1 to the EAX register
  movl  %eax, -4(%ebp)            ## Copy the EAX register back on to the stack at the address for i.
  jmp LBL1                        ## Go back to the i < 10 comparison
LBL3:
  ...                             ## Loop has been exited

## for (int i = 0; i < 10; ++i) { }

LBL1:                             ## Hint: These instructions are identical
  cmpl  $10, -4(%ebp)
  jge LBL3
  jmp LBL2
LBL2:
  movl  -4(%ebp), %eax
  addl  $1, %eax
  movl  %eax, -4(%ebp)
  jmp LBL1
LBL3:
  ...