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Re: proposed Opengroup action for c99 command (XCU ERN 76)


Joseph S. Myers said:
> On Fri, 16 Sep 2005, Zack Weinberg wrote:
>> I am with Joe Buck in the opinion that even a 1% performance penalty for
>> implementing (A) [or (B)] would be too much -- I suggest this be fixed by
>> convincing the C++ committee to allow (C) and not just by phase 1
>> transformations, thus allowing the existing implementation to conform.
>
> I don't think solutions starting with convincing the committee to fix a
> working part of the standard are generally that practical!

When the standard is arguably buggy -- if nothing else, it diverges from C
and there is no good reason for divergence -- I think working with the committee
to improve the standard should always be an option considered.

When a simple change to the standard would get you out of having to make
a large, complicated change to GCC, and when the standard-mandated semantics
are of dubious utility to real users, I think you should try to change the
standard before you even start thinking about changing the compiler.

I don't disagree strongly with any of your other points, but I do want to
mention that foreclosing future improvements in another domain is something
that should be
considered when making implementation choices, that proper statistical methods
*can* detect 1% performance degradations amid the noise, and that -- as
pointed out by others -- a pile of 1% degradations adds up to a slow compiler.

zw



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