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Re: Fixing Bugs (Was: A Suggestion for Release Testing)
On Tue, 14 Jun 2005, Scott Robert Ladd wrote:
> If I were to present a patch that implements the recomendations of the
> Numerical C Extensions Group, would it be accepted or rejected (on the
> subject alone; ignore for the moment potential technical bugs in the
> submitted code)?
I don't know to what recommendations you refer (please give a URL). I
would consider a patch resolving issue 323 by implementing the C90/C99
standard requirements for how excess precision works to be desirable.
That is, excess precision should be explicitly modeled throughout the
compiler (rather than the x86 back end pretending it can operate on float
and double); not just assignments but also casts and function call and
return should discard excess precision (including cast from a type to
itself, etc.; and see also DR#318); and arithmetic on constants should use
excess precision the same way as at runtime; this should all be enabled by
-ansi / -std=c89 / -std=c99 and disabled by -fno-float-store. This would
allow predictable operation in accordance with the standards on processors
where excess precision is natural.
I think changing the default precision must be a matter for -m options;
these would also affect the ABI by changing the size of long double and
libraries written to use long double in computations of functions for
double would cease to work with a different precision.
--
Joseph S. Myers http://www.srcf.ucam.org/~jsm28/gcc/
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