Rearranging FP expressions
Rob Carriere
rob at kaa.eng.ohio-state.edu
Wed Sep 28 00:30:03 AEST 1988
In article <4700017 at m.cs.uiuc.edu> wsmith at m.cs.uiuc.edu writes:
>[...]
>The problem: How can C know when it is safe to rearrange expressions,
> especially floating point expressions.
>
>A proposed solution:
> Expressions enclosed in double parentheses may not be rearranged,
> all other expressions may be rearranged in "semantically valid"
> ways.
>[examples]
This could lead to trouble with macro expansions. Otherwise it looks
fine to me at least. Another way of doing this might be a pair of
pragma's, one to say ``hands off this one'', and one to say ``you can
totally optimize this''.
I know it is dubious whether the current standard allows such pragmae
(sp :-), but the original poster was talking about future efforts
anyway.
Rob Carriere
More information about the Comp.lang.c
mailing list