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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug sanitizer/60613] New: Invalid signed subtraction ubsan diagnostics
Date: Fri, 21 Mar 2014 14:44:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: sanitizer
X-Bugzilla-Version: 4.9.0
X-Bugzilla-Keywords: wrong-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: jakub at gcc dot gnu.org
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: jakub at gcc dot gnu.org
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60613

            Bug ID: 60613
           Summary: Invalid signed subtraction ubsan diagnostics
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: jakub at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org

On x86_64-linux with -O2 -m32 -fsanitize=undefined on:
__attribute__((noinline, noclone)) long long
foo (long long y)
{
  asm ("");
  return 8LL - y;
}

int
main ()
{
  foo (1);
  return 0;
}

we get invalid diagnostics:
runtime error: signed integer overflow: 8 - 1 cannot be represented in type
'long long int'