This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: mips SNaN/QNaN is swapped
- From: Alexandre Oliva <aoliva at redhat dot com>
- To: Richard Henderson <rth at redhat dot com>
- Cc: cgd at broadcom dot com, gcc-patches at gcc dot gnu dot org
- Date: 01 Apr 2003 10:27:40 -0300
- Subject: Re: mips SNaN/QNaN is swapped
- Organization: GCC Team, Red Hat
- References: <orr88we85f.fsf@free.redhat.lsd.ic.unicamp.br><orisu8e2f3.fsf@free.redhat.lsd.ic.unicamp.br><20030325034356.GE15567@redhat.com><orsmtbaido.fsf@free.redhat.lsd.ic.unicamp.br><20030327012642.GA29837@redhat.com><orn0jhfpyh.fsf@free.redhat.lsd.ic.unicamp.br><20030327093138.GC16558@redhat.com><mailpost.1048757677.18699@news-sj1-1> <yov5r88sbvvu.fsf@broadcom.com><or4r5iq4ze.fsf@free.redhat.lsd.ic.unicamp.br><20030401053433.GA25974@redhat.com>
On Apr 1, 2003, Richard Henderson <rth at redhat dot com> wrote:
> You've missed the needed change to real_identical. In this case,
> if canonical, you should ignore the significand. This implies a
> needed change to real_hash as well.
AFAICT, this also exposes a flaw in the very notion of the `canonical'
bit. __builtin_nan("0") and 0.0/0.0 will not pass real_identical(),
even though they produce the same bit pattern when converted to the
target format, if the target format has qnan_msb_set. I still feel
this is heading the wrong way :-(
--
Alexandre Oliva Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer aoliva at {redhat dot com, gcc.gnu.org}
CS PhD student at IC-Unicamp oliva at {lsd dot ic dot unicamp dot br, gnu.org}
Free Software Evangelist Professional serial bug killer