Re: behavior-preserving optimization in C, was compiler bugs

Pertti Kellomaki <pertti.kellomaki@tut.fi>
Mon, 18 May 2009 12:48:10 +0300

          From comp.compilers
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[13 later articles]
| List of all articles for this month |
From: Pertti Kellomaki <pertti.kellomaki@tut.fi>
Newsgroups: comp.compilers
Date: Mon, 18 May 2009 12:48:10 +0300
Organization: Compilers Central
References: 09-04-072 09-04-086 09-05-010 09-05-022 09-05-028 09-05-038 09-05-039 09-05-050 09-05-055 09-05-065 09-05-069
Keywords: optimize, Scheme
Posted-Date: 18 May 2009 12:54:36 EDT

Anton Ertl wrote:
> * Do you analyse the program to see if it is actually
> standard-conformant? If it isn't, do you consider the program to be
> incorrect, the optimizer to be correct, and do you mark the bug
> report as invalid? Then you are an apologist. If you don't write
> optimizers, but think that this attitude is ok, then you are also an
> apologist.


Or a formalist. For example, the Scheme specification does not specify
the order in which function arguments are evaluated. As far as I am
concerned, an implementation would be free to evaluate arguments left
to right on weekdays and right to left on weekends. If my code relies
on something that is not explicitly promised by the language, that's
my fault, not the compiler's.
--
Pertti

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