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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Subject: Re: Eliminating copying in Gnat
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Georg Bauhaus <sb463ba@l1-hrz.uni-duisburg.de> writes:

> Victor Porton <porton@ex-code.com> wrote:
> :  But Adjust is called 3 times :-(
> 
> Are compilers allowed to optimize away an Adjust?

Yes.  There is an AI about exactly when it can.

> Might Adjust not have side effects?

Yes, but they better be the sort of side effects that are benign under
the allowed optimizations.  For example, if the type is doing reference
counting, the compiler can optimize away matched pairs of
increment/decrement.  But if Adjust prints "Hello, world.",
the programmer should not expect to see an exact number of
"Hello, world."'s printed on the screen.

- Bob