Re: LuaJIT2 performance for number crunching

[Alexander Gladysh <agladysh@...>]

On Wed, Feb 16, 2011 at 19:29, Philippe Lhoste <PhiLho@gmx.net> wrote:
> On 16/02/2011 17:16, Mike Pall wrote:

>> Rule #437: Never hoist out constants (if possible)!

>> Always write constants inline, otherwise they are treated as
>> variables, which generates worse code. And, yes, even plain Lua is
>> able to fold 1/5 into a constant. It's important to write these
>> unambiguously -- FP arithmetic is not associative!

> Good to know, but bad programming practice from a formal point of view. :-)
> I always recommend to beginners in programming to replace magic numbers with
> constants, for readability and consistency. I understand that speed
> optimizations sometime have to break these nice rules (like manual loop
> unrolling and such).

My opinion as well.

Alexander.