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[CypherJF]

An interesting article:

http://www-128.ibm.com/developerworks/power/library/pa-unrollav3/

I haven't had time to read it completely
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Performance is often the art of cheating carefully. - James Gosling

[Mr Ekted]

Classic example (if you care about speed):

Code: Show/Hide // bad code for (i = 0; i < 1000000; i++)    {    if (something)       Func1(i);    else       Func2(i);    } // good code if (something)    for (i = 0; i < 1000000; i++)       Func1(i); else    for (i = 0; i < 1000000; i++)       Func2(i);

Of course this is a hypothetical case. You would more likely embed the loops in the functions instead of calling them a million times.
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4,691 irradiated haggis!

[Cyan~Fire]

That article wasn't really about optimizing loops, it was optimizing loops with AltiVec or whatever.

What Ekted said applies far more to the majority of us. (Those of us who don't use PowerPCs?)
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Wise men STILL seek Him.

[Dr Brain]

Shouldn't any decent optimizer fix that, ekted?

Besides, readability is far more important that efficiency in ~90% of cases.
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Hyperspace Owner

Smong> so long as 99% deaths feel lame it will always be hyperspace to me

[Mr Ekted]

I would agree in most cases, but if you are writing something that absolutely has to be killer fast--maybe you would even go so far as to profile it--then this is something you would seriously consider. A thousand loops, no big deal, A million, you are starting to get iffy.

[Maverick]

[D1st0rt]

It only has to do the conditional branch once.
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[Maverick]

[D1st0rt]

In the first example, it has to do the if 1000000 times. In the second, it does it once.

[Maverick]

aaaah... but two for loops of that size should still make up more cpu cycles then one (with the if() )? Or am I mistaken..

[Cyan~Fire]

It'll be executing more than one command in ASM, if that's what you mean. But in both cases, the for loop commands stay the same, but the conditional code only has to be done once in the second, which obviously makes it faster no matter how long the for()s take.

[D1st0rt]

In the second example, only one of the loops gets run

[SamHughes]

What should I do if looping through branches a million times is my favorite form of gambling?

[Bak]

[Maverick]