Thread: Will too much IF STATEMENT decrease performance

This is related with the project I'm working on at work.

Performance and reliability is a big issue for my project.
I need to do a lot of condition check in my program in-order to produce valid output and ensure all undesireable condition needs to get handled.

Therefore, there is a lot of IF condition in many of my function, and a lot of them is nested IF statement.

I try to look for some reference online and book, but it seems like there little to none information about it.

What do you guys think? Do you think IF STATEMENT will decrease program run-time performance?

They could give you a performance hit, but what alternative could you use? The ifs cannot very well be ripped out. All you would be able to do what manofsteel972 suggested. Unless you're on some sort of embedded system, it's not something you should worry about too much.

It's not just multi-threaded code, it's any code that is being run on a processor that runs out-of-order execution. The Pentium for instance does a great job at branch prediction and will guess what the outcome of an comparison will be, and then proccess a few lines of code based on that prediction. But if that prediction was wrong, the processor has to stop itself, refetch, and decode another set of operations.

Yeah, not too much of a big deal, but it's something that you should keep in mind when trying to optimize.

Do a search on optimization. Basically if the project is done don't worry about minimal optimzations. You should be worried about the algorithms used and whatnot. If states are fairly quick in of itself. Granted if you are comparing a user defined that takes a long time to return a boolean result then yeah a lot of ifs will be a performance hit.

Thanks for everyone for replying.

I'll look into it tomorrow when I go back to work and maybe factor out some of the IF statement. Put the most common case first, and the less common case after.

You can use bit Signature to convert if statements... still it depends on your problem, however you can use Bit signature as alternative each having an action if that success .. like if you have 10 if (and else) you can have 10 bits to represent your problem and say a particular signature execute that code .. Bit calculations are faster and it also provides much cleaner code ...