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Re: Rewrite some jump.c routines to use flags
- From: Eric Botcazou <ebotcazou at adacore dot com>
- To: Richard Sandiford <richard dot sandiford at arm dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Sun, 14 Jul 2019 21:15:50 +0200
- Subject: Re: Rewrite some jump.c routines to use flags
- References: <email@example.com> <4683101.0dOKtXP93x@polaris> <firstname.lastname@example.org>
> AIUI, neither ORDERED nor UNEQ trap on signalling NaNs. Without this,
> the follow-on patch would fold
> (and (ordered x y) (uneq x y)) -> (eq x y)
> which is the same thing for quiet NaNs but not for signalling NaNs.
Note that GCC defaults to -fno-signaling-nans and the transformation would be
valid in this mode.