-Wdouble-promotion & noise

Ian Lance Taylor iant@google.com
Wed Sep 15 00:02:00 GMT 2010


tbp <tbptbp@gmail.com> writes:

> On Tue, Sep 14, 2010 at 8:44 PM, Ian Lance Taylor <iant@google.com> wrote:
>> Let me put it a different way: what is it that you want, expressed in
>> terms of C/C++ code?  What should the compiler be warning about?
> Hmm. I think the provided example captures most of what i care about,
>   float area(float radius) { return 3.14159 * radius * radius; }
> and even forgotten/disguised uses of, say, M_PI, would fall in that
> category after-all.

We are talking at cross-purposes.  You have provided two examples.  The
compiler can't implement examples.  The compiler can only implement some
sort of definition.  So far my best guess is that your definition is
"warn about implicit conversions from float to double except for those
conversions caused by default argument promotion applied to arguments
passed to unnamed parameters."  Is that what you want?

Ian



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