RE: GCC beaten by ICC in stupid trig test!

["Dave Korn" <dk at artimi dot com>]

> -----Original Message-----
> From: gcc-owner On Behalf Of Paul Brook
> Sent: 24 March 2004 18:53

> > Well, first this (transforming (a+b)+c to a+(b+c)) would be 
> a question 
> > of if the language standard permits this.  After this, I personally 
> > would like to have a way to override associativity, and I 
> cannot see a 
> > clearer way as to write (a+b)+c instead of a+b+c.  But that 
> may be a 
> > language standard question again.  If (a+b)+c doesn't do 
> it, I cannot 
> > see another way of really forcing evaluation order.
> 
> The Fortran standard specifies that you can reorder a+b+c, 
> but not (a+b)+c. 
> Basically you must preserve paretheses, anything else is fair 
> game. The exact wording is "any mathematically equivalent 
> expression". I don't know what the C standard specifies on this issue.
> 
> We don't currently have a way of representing this. We're 
> either overly conservative, or violate the standard.
> 
> Paul

  IIUIC the fact that the + operator is specified in the standard as binding
left-to-right imply that "a + b + c" with no brackets *has* to be
interpreted as "(a + b) + c".

  Either that, or I'm being dumb.


    cheers, 
      DaveK
-- 
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