[Boost-bugs] [Boost C++ Libraries] #13558: gcd(INT_MIN, INT_MIN) crashes

Subject: [Boost-bugs] [Boost C++ Libraries] #13558: gcd(INT_MIN, INT_MIN) crashes
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2018-05-02 20:28:08

#13558: gcd(INT_MIN, INT_MIN) crashes
--------------------------------------+---------------------
 Reporter:  Evan Driscoll <evaned@…>  |      Owner:  (none)
     Type:  Bugs                      |     Status:  new
Milestone:  To Be Determined          |  Component:  None
  Version:  Boost 1.67.0              |   Severity:  Problem
 Keywords:                            |
--------------------------------------+---------------------
 The following produces a SIGFPE for me:

 {{{#!c++
 #include <iostream>
 #include <climits>
 #include <boost/integer/common_factor_rt.hpp>

 int main()
 {
     std::cout << boost::integer::gcd(INT_MIN, INT_MIN);
 }
 }}}

 because it simplifies `gcd(INT_MIN, INT_MIN)` => `gcd(INT_MIN % INT_MIN,
 INT_MIN)` => `gcd(0, INT_MIN)` => `gcd(0, INT_MIN % 0)` => gcd(0,
 SIGFPE)`.

 I'm actually not sure what the right behavior is (the documented behavior
 is that the return is always positive, and, for example, `gcd(-2, -2)`
 returns 2, but obviously you can't do that here).

 Boost 1.63 returned `INT_MIN` in this case, which seems like the best
 answer.

 Responsible commit:
 https://github.com/boostorg/integer/commit/beb68718640150f67fe5671bbbb7848d9e7170b8

-- 
Ticket URL: <https://svn.boost.org/trac10/ticket/13558>
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