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From: nathan@gcc.gnu.org
To: gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org,
	lprimak@hope.nyc.ny.us, nobody@gcc.gnu.org
Subject: Re: c++/7322: Code to Compute Numeric Limits "runs away" when -O<any> used
Date: Tue, 16 Jul 2002 01:41:00 -0000	[thread overview]
Message-ID: <20020716084143.25040.qmail@sources.redhat.com> (raw)

Synopsis: Code to Compute Numeric Limits "runs away" when -O<any> used

State-Changed-From-To: open->closed
State-Changed-By: nathan
State-Changed-When: Tue Jul 16 01:41:42 2002
State-Changed-Why:
    The code is ill formed.
    There are tests such as
    	if (T (max + 1) > max)
    where max & T are signed types. [5]/5 says that
    if the result is not in the range if representable values,
    the behaviour is undefined. gcc implements modulo arithmetic
    for unsigned types, and undefined behaviour for signed types.
    The optimized therefore knows that max + 1 must always
    be greater than max.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=7322


             reply	other threads:[~2002-07-16  8:41 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-07-16  1:41 nathan [this message]
  -- strict thread matches above, loose matches on Subject: below --
2002-07-15 19:56 lprimak

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