[Bug libstdc++/5625] [mips] exception unwinding creates invalid pointer on mips

[cgd at broadcom dot com]

------- Additional Comments From cgd at broadcom dot com  2004-02-05 06:25 -------
Subject: Re:  [mips] exception unwinding creates
 invalid pointer on mips

At 5 Feb 2004 02:45:07 -0000, wilson at gcc dot gnu dot org wrote:
> This patch changes the MIPS backend to use DImode for Pmode when generating
> 64-bit ILP32 code, instead of SImode as it currently does.

I'm a bit concerned about this comment, because SImode values in
registers on MIPS should be in their properly sign-extended forms.

If they aren't, patterns like addsi3 (-> addu) will not work properly
under all conditions.  (addu and other 32-bit arithmetic ops are
UNPREDICTABLE if operands don't have bits 63:32 matching bit 31, i.e.,
if they're not sign extended.  mipsisa64 sim should be reporting that,
as I believe you've noticed.)


Sorry if i manage to help get bug closed prematurely.  That's what
happens when a PHB tries to do real work. 8-)


chris



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=5625