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Re: [middle-end,patch] Making __builtin_signbit type-generic
- From: Andreas Schwab <schwab at suse dot de>
- To: FX <fxcoudert at gmail dot com>
- Cc: gcc-patches <gcc-patches at gcc dot gnu dot org>, Uros Bizjak <ubizjak at gmail dot com>, Joseph Myers <joseph at codesourcery dot com>
- Date: Wed, 19 Aug 2015 10:54:52 +0200
- Subject: Re: [middle-end,patch] Making __builtin_signbit type-generic
- Authentication-results: sourceware.org; auth=none
- References: <BB1A5070-5A21-4393-A5B8-0C320B020902 at gmail dot com> <alpine dot DEB dot 2 dot 10 dot 1508171522570 dot 29836 at digraph dot polyomino dot org dot uk> <C8DC1045-215B-4FCF-8EA3-F2E08A8E325F at gmail dot com>
FX <fxcoudert@gmail.com> writes:
> @@ -80,6 +80,24 @@ foo_1 (float f, double d, long double ld
> if (__builtin_finitel (ld) != res_isfin)
> __builtin_abort ();
>
> + /* Sign bit of zeros and nans is not preserved in unsafe math mode. */
> +#ifdef UNSAFE
> + if (!res_isnan && d != 0)
> +#endif
Why only in usafe mode? Isn't the sign bit of NaN always unreliable?
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
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