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From: "law at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/57124] 254.gap@spec2000 got miscompare after r198413
Date: Wed, 01 May 2013 05:13:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57124

--- Comment #2 from Jeffrey A. Law <law at redhat dot com> 2013-05-01 05:13:38 UTC ---
__attribute__ ((noinline))
foo(short unsigned int *p1, short unsigned int *p2)
{
  short unsigned int x1, x4;
  int x2, x3, x5, x6;
  unsigned int x7;

  x1 = *p1;
  x2 = (int) x1;
  x3 = x2 * 65536;
  x4 = *p2;
  x5 = (int) x4;
  x6 = x3 + x4;
  x7 = (unsigned int) x6;
  if (x7 <= 268435455U)
    abort ();
  exit (0);
}

main()
{
  short unsigned int x, y;
  x = -5;
  y = -10;
  foo (&x, &y);
}


Is a much reduced testcase.  Ultimately we have a range for x6 that's [0,
+INF(OVF)] at which point it's not safe to replace x7 with x6 in the
conditional.