Re: What do you get when you multiply a number with 1

Does the RPG compiler have an optimizer?

Joe Pluta wrote:

Add is faster than multiply.  Even faster is a straight assign.  For a loop
of 500,000 iterations, the milliseconds are shown below.  "None" is for an
empty loop.  Add is about 40% faster than multiple, assign is about 8%
faster than add.

DSPLY  None: 136 Mult: 710 Add: 519 Assign: 481

Here's the code:

d T0 s z d T1 s z d T2 s z d T3 s z d T4 s z d x s 10u 0 d MAX c 500000 d a s 3u 0 d b s 4s 1 inz(123.5) d dnone s 10u 0 d dmult s 10u 0 d dadd s 10u 0 d dasgn s 10u 0 d msg s 52 /free t0 = %timestamp(); for x = 1 to MAX; endfor; t1 = %timestamp(); for x = 1 to MAX; eval(h) a = b * 1; endfor; t2 = %timestamp(); for x = 1 to MAX; eval(h) a = b + 0; endfor; t3 = %timestamp(); for x = 1 to MAX; eval(h) a = b; endfor; t4 = %timestamp(); dnone = %diff( t1: t0: *MSECONDS) / 1000;

 dmult = %diff( t2: t1: *MSECONDS) / 1000;
 dadd  = %diff( t3: t2: *MSECONDS) / 1000;
 dasgn = %diff( t4: t3: *MSECONDS) / 1000;

eval msg = 'None: ' + %char(dnone) + ' Mult: ' + %char(dmult) + ' Add: ' + %char(dadd) + ' Assign: ' + %char(dasgn); dsply msg; *inlr = *on; /end-free