Re: [PATCH] Fix truncf for sNaN input

Keith Packard via Newlib <[email protected]> Wed, 11 Mar 2020 13:48:26 -0700

Newsgroups	gmane.comp.lib.newlib
Message-ID	<[email protected]>

Fabian Schriever <[email protected]> writes:

> Make line 47 in sf_trunc.c reachable. While converting the double
> precision function trunc to the single precision version truncf an error
> was introduced into the special case. This special case is meant to
> catch both NaNs and infinities, however qNaNs and infinities work just
> fine with the simple return of x (line 51). The only error occurs for
> sNaNs where the same sNaN is returned and no invalid exception is
> raised.

I think this isn't right. According to the trunc/truncf man page:

       If x is integral, infinite, or NaN, x itself is returned.

I think this means that we should just return x in these cases, and not
raise an exception?

The same appears to be true for the other similar functions, including
floor, ceil, round, rint and nearbyint.

-- 
-keith

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