GNU bug report logs - #17681
24.3.91; "Arithmetic Error" in hide-ifdef mode when using shift operators

Previous Next

Full log

View this message in rfc822 format

From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Noam Postavsky <npostavs <at> users.sourceforge.net>
Cc: tracker <at> debbugs.gnu.org
Subject: bug#17681: closed (24.3.91; "Arithmetic Error" in hide-ifdef mode
 when using shift operators)
Date: Sun, 26 Jun 2016 04:54:02 +0000

[Message part 1 (text/plain, inline)]

Your message dated Sun, 26 Jun 2016 00:53:39 -0400
with message-id <CAM-tV-_vVhHkJzS2vU9jZWytD9GLzuHNWHP9oMKUBczqecTJQw <at> mail.gmail.com>
and subject line Re: bug#17681: 24.3.91; "Arithmetic Error" in hide-ifdef mode when using shift operators
has caused the debbugs.gnu.org bug report #17681,
regarding 24.3.91; "Arithmetic Error" in hide-ifdef mode when using shift operators
to be marked as done.

(If you believe you have received this mail in error, please contact
help-debbugs <at> gnu.org.)


-- 
17681: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=17681
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

[Message part 2 (message/rfc822, inline)]

From: David Engster <deng <at> randomsample.de>
To: bug-gnu-emacs <at> gnu.org
Subject: 24.3.91;
 "Arithmetic Error" in hide-ifdef mode when using shift operators
Date: Tue, 03 Jun 2014 21:12:33 +0200

Recipe:

- Create a file "test.h" containing the following (this is from
  the file 'jiffies.h' in the Linux kernel):

#if !((((NSEC_PER_SEC << 2) / TICK_NSEC) << (SEC_JIFFIE_SC - 2)) & 0x80000000)
#endif

- emacs -Q

- Load the file, activate hide-ifdef-mode

- C-c @ h  (hide-ifdefs)

The minibuffer will show "Arithmetic Error". Here is the backtrace:

Debugger entered--Lisp error: (arith-error)
  hif-divide(0 nil)
  (hif-shiftleft (hif-divide (hif-shiftleft (hif-lookup (quote NSEC_PER_SEC)) 2) (hif-lookup (quote TICK_NSEC))) (hif-minus (hif-lookup (quote SEC_JIFFIE_SC)) 2))
  (hif-logand (hif-shiftleft (hif-divide (hif-shiftleft (hif-lookup (quote NSEC_PER_SEC)) 2) (hif-lookup (quote TICK_NSEC))) (hif-minus (hif-lookup (quote SEC_JIFFIE_SC)) 2)) 2147483648.0)
  (hif-not (hif-logand (hif-shiftleft (hif-divide (hif-shiftleft (hif-lookup (quote NSEC_PER_SEC)) 2) (hif-lookup (quote TICK_NSEC))) (hif-minus (hif-lookup (quote SEC_JIFFIE_SC)) 2)) 2147483648.0))
  eval((hif-not (hif-logand (hif-shiftleft (hif-divide (hif-shiftleft (hif-lookup (quote NSEC_PER_SEC)) 2) (hif-lookup (quote TICK_NSEC))) (hif-minus (hif-lookup (quote SEC_JIFFIE_SC)) 2)) 2147483648.0)))
  hif-possibly-hide()
  hide-ifdef-guts()
  hide-ifdefs()

Earlier Emacsen did not throw an error here (although it is very
possible that the above line wasn't calculated correctly). Still, this
probably qualifies as a regression.

-David

[Message part 3 (message/rfc822, inline)]

From: Noam Postavsky <npostavs <at> users.sourceforge.net>
To: 17681-done <at> debbugs.gnu.org
Subject: Re: bug#17681: 24.3.91; "Arithmetic Error" in hide-ifdef mode when
 using shift operators
Date: Sun, 26 Jun 2016 00:53:39 -0400

Version: 25.0.95

I see the problem in Emacs 24.5, but not Emacs 25.0.95, so it seems to
have been fixed sometime in between.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.