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Re: [RFC] PR/24900: computed but not used cast values
On Thu, Nov 17, 2005 at 02:54:48PM -0800, Richard Henderson wrote:
> On Thu, Nov 17, 2005 at 02:01:56PM -0800, Ian Lance Taylor wrote:
> > We traditionally do not warn about not using the value returned by a
> > function. And I don't see why adding a cast should change that.
> > Intuitively, a cast by itself is not a computation.
>
> In many cases is certainly is -- it's a value transformation;
> zero extension, floating-point conversion, etc.
>
> My opinion is: why is the user asking for a value to be
> transformed if they're not going to use the result?
As in the example, these cases will usually arise in macros, where under
some circumstances some computation will be wasted.