How to be confident of copy elision / return-value optimization

Asked Nov 20 '15 at 13:15

Active Nov 20 '15 at 13:17

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I often return objects by value, assuming that copy elision / RVO will happen.

But I don't have a good under-the-hood understanding of compilers, and the possibility that sometimes something in my code might sabotage copy elision without my knowledge, scares me.

Is there a simple set of rules to bear in mind under which I can be reasonably confident that copy elision happens (or at least, that I am not preventing it)?

asked Nov 20 '15 at 13:15

Museful

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The simple rule is to profile your program and concentrate on performance hotspots. – Kerrek SB Nov 20 '15 at 13:16
Have a look at http://en.cppreference.com/w/cpp/language/copy_elision – Claudio Nov 20 '15 at 13:24
@KerrekSB Are you suggesting I should pass and return everything by value until the profiler gives me reason to do otherwise? – Museful Nov 23 '15 at 22:23
@tennenrishin: That would be a pretty good start, yes. – Kerrek SB Nov 23 '15 at 22:24

How to be confident of copy elision / return-value optimization

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