RE: libstdc++/5625: exception unwinding creates invalid pointer o n mips

[Eric Christopher <echristo@redhat.com>]

The following reply was made to PR libstdc++/5625; it has been noted by GNATS.

From: Eric Christopher <echristo@redhat.com>
To: Ed Maste <emaste@SANDVINE.com>
Cc: "'echristo@gcc.gnu.org'" <echristo@gcc.gnu.org>,
   "'gcc-bugs@gcc.gnu.org'"
	 <gcc-bugs@gcc.gnu.org>,
   "'gcc-prs@gcc.gnu.org'" <gcc-prs@gcc.gnu.org>,
   "'gcc-gnats@gcc.gnu.org'"
	 <gcc-gnats@gcc.gnu.org>
Subject: RE: libstdc++/5625: exception unwinding creates invalid pointer o n
	mips
Date: 23 Apr 2002 12:44:46 -0700

 On Tue, 2002-04-23 at 12:35, Ed Maste wrote:
 > Yes, the MIPS documentation states that the destination register 
 > gets the sign-extended result ("GPR[rt]<-sign_extend(temp31..0)").
 > 
 > However, note the ADDIU instruction Restrictions section:
 > 
 >      Restrictions:
 >      If GPR rs does not contain a sign-extended 
 >      32-bit value (bits 63..31 equal), then the 
 >      result of the operation is UNPREDICTABLE.
 > 
 
 So it sounds like both your processor and gcc are in error. gcc by not
 sign extending the value before and you for not sign extending it after.
 
 I'll take a look at the sign extension requirements in the back end.
 
 -eric
 
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