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From: Robert A Duff <bobduff@world.std.com>
Subject: Re: Right of Optimize Eager Evaluation Away
Date: 1999/11/28
Message-ID: <wccr9haibu3.fsf@world.std.com>#1/1
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Sender: bobduff@world.std.com (Robert A Duff)
References: <863dtqfo26.fsf@ppp-173-146.villette.club-internet.fr>
Organization: The World Public Access UNIX, Brookline, MA
Newsgroups: comp.lang.ada
Date: 1999-11-28T00:00:00+00:00
List-Id: <comp.lang.ada>

Laurent Guerby <guerby@acm.org> writes:

> The question is: is a smart Ada 95 compiler allowed to generate code
> that looks like this:
> 
>    if C then
>       X := Super_Expensive_Function_Call_1;
>    else
>       X := Super_Expensive_Function_Call_2;
>    end if;
> 
> that is to say, be lazy about its argument, and so might
> save execution time.

No.  The function arguments may be evaluated in either order, so in case
of exception, the other one might not happen.  But without exceptions,
both arguments will be evaluated.

- Bob