Using distributive property to optimize.

[Karl Heuer]

In article <CHUCKP.90Feb13065634 at halley.ncr-fc.FtCollins.NCR.com> chuckp at ncr-fc.FtCollins.NCR.com (Chuck Phillips) writes:
>Agreed.  In the spirit of C, the compiler _should_, by default, have the
>freedom to rearrange an expression (take advantage of distributivity, etc.).
>However, there are times when you _really need_ to explicitly control the
>order and means of evaluation.

Please describe such a circumstance.  I believe that all such are covered by
the new ANSI C rules%, and hence there is no need for extensions like your
proposed "cast-to-volatile".

Karl W. Z. Heuer (karl at ima.ima.isc.com or harvard!ima!karl), The Walking Lint
Followups to comp.lang.c only; this isn't really C++ related.
________
% Briefly, the rule is that the implementation is permitted to rearrange only
  through the grace of the as-if rule: i.e., only if the result obtained is
  indistinguishable from that of the abstract machine.  Lvalues with the
  "volatile" attribute must be loaded and stored as per the abstract machine.