[Bug sanitizer/60613] New: Invalid signed subtraction ubsan diagnostics

[Bug sanitizer/60613] New: Invalid signed subtraction ubsan diagnostics

[jakub at gcc dot gnu.org]

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'

[Bug sanitizer/60613] Invalid signed subtraction ubsan diagnostics

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60613

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-03-21
                 CC|                            |mpolacek at gcc dot gnu.org
   Target Milestone|---                         |4.9.0
     Ever confirmed|0                           |1

[Bug sanitizer/60613] Invalid signed subtraction ubsan diagnostics

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60613

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 32423
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32423&action=edit
gcc49-pr60613.patch

Untested fix.

[Bug sanitizer/60613] Invalid signed subtraction ubsan diagnostics

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60613

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Sat Mar 22 16:25:50 2014
New Revision: 208766

URL: http://gcc.gnu.org/viewcvs?rev=208766&root=gcc&view=rev
Log:
    PR sanitizer/60613
    * internal-fn.c (ubsan_expand_si_overflow_addsub_check): For
    code == MINUS_EXPR, never swap op0 with op1.

    * c-c++-common/ubsan/pr60613-1.c: New test.
    * c-c++-common/ubsan/pr60613-2.c: New test.

Added:
    trunk/gcc/testsuite/c-c++-common/ubsan/pr60613-1.c
    trunk/gcc/testsuite/c-c++-common/ubsan/pr60613-2.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/internal-fn.c
    trunk/gcc/testsuite/ChangeLog

[Bug sanitizer/60613] Invalid signed subtraction ubsan diagnostics

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60613

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.