[Bug analyzer/99669] New: RFE: detect division by zero in analyzer

[Bug analyzer/99669] New: RFE: detect division by zero in analyzer

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99669

            Bug ID: 99669
           Summary: RFE: detect division by zero in analyzer
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: analyzer
          Assignee: dmalcolm at gcc dot gnu.org
          Reporter: dmalcolm at gcc dot gnu.org
  Target Milestone: ---

-fanalyzer could probably warn about division by zero:

Consider this easy case (from
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89863#c7):

extern void g();

void f()
{
    unsigned int vsync_rate_hz = 0;
    unsigned int frame_time_microsec = 1000000 / vsync_rate_hz;

    g();
}

See also bug 80744 (same idea but for C++)

PVS-Studio complains about this:
  https://www.viva64.com/en/w/v609/
  https://www.viva64.com/en/examples/v609/
which has interprocedural examples, and an example of a loop where we could
"know" that the iterator could be zero.

CWE-369: Divide By Zero:
  https://cwe.mitre.org/data/definitions/369.html

[Bug analyzer/99669] RFE: detect division by zero in analyzer

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99669

--- Comment #1 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
I implemented a version of this (-Wanalyzer-tainted-divisor) for GCC 12 in:
  https://gcc.gnu.org/pipermail/gcc-patches/2021-November/584356.html

[Bug analyzer/99669] RFE: detect division by zero in analyzer

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99669

David Malcolm <dmalcolm at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|                            |105887

--- Comment #2 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
See also:
  https://clang.llvm.org/docs/analyzer/checkers.html#core-dividezero-c-c-objc


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105887
[Bug 105887] RFE: clang analyzer warnings that GCC's -fanalyzer could implement

[Bug analyzer/99669] RFE: detect division by zero in analyzer

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99669

David Malcolm <dmalcolm at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |geoffreydgr at icloud dot com

--- Comment #3 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
*** Bug 109201 has been marked as a duplicate of this bug. ***