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Date: Thu, 18 Aug 2005 22:41:00 -0000
From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Message-ID: <20050818223642.23470.pinskia@gcc.gnu.org>
Reply-To: gcc-bugzilla@gcc.gnu.org
Subject: [Bug middle-end/23470] New: a*a (for floats) is not considered always postive
X-Bugzilla-Reason: CC
X-SW-Source: 2005-08/txt/msg02156.txt.bz2
List-Id: <gcc-bugs.sourceware.org>

While looking into PR 23452, I noticed this:
double pow(double, double);
int f(double a, double b)
{
  if (((a*a) + (b*b))<0)
    link_error();
}

There should be no reference to link_error as a*a is always postive.  Note really 
__builtin_pow (a, 2.0e+0) is what is folded to first.

-- 
           Summary: a*a (for floats) is not considered always postive
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23470