From 4991d82385c9cb215ce5230c90b452a8b7f31d91 Mon Sep 17 00:00:00 2001
From: jzmaddock <john@johnmaddock.co.uk>
Date: Mon, 24 Apr 2017 19:19:48 +0100
Subject: [PATCH] Need to take abs of return value in short-circuit gcd code.

---
 include/boost/integer/common_factor_rt.hpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/boost/integer/common_factor_rt.hpp b/include/boost/integer/common_factor_rt.hpp
index d27f094..2f65d67 100644
--- a/include/boost/integer/common_factor_rt.hpp
+++ b/include/boost/integer/common_factor_rt.hpp
@@ -447,9 +447,9 @@ template <typename Integer>
 inline BOOST_CXX14_CONSTEXPR Integer gcd(Integer const &a, Integer const &b) BOOST_GCD_NOEXCEPT(Integer)
 {
     if(a == (std::numeric_limits<Integer>::min)())
-       return a == static_cast<Integer>(0) ? b : gcd(static_cast<Integer>(a % b), b);
+       return a == static_cast<Integer>(0) ? gcd_detail::gcd_traits<Integer>::abs(b) : gcd(static_cast<Integer>(a % b), b);
     else if (b == (std::numeric_limits<Integer>::min)())
-       return b == static_cast<Integer>(0) ? a : gcd(a, static_cast<Integer>(b % a));
+       return b == static_cast<Integer>(0) ? gcd_detail::gcd_traits<Integer>::abs(a) : gcd(a, static_cast<Integer>(b % a));
     return gcd_detail::optimal_gcd_select(static_cast<Integer>(gcd_detail::gcd_traits<Integer>::abs(a)), static_cast<Integer>(gcd_detail::gcd_traits<Integer>::abs(b)));
 }