* bignum.c (big_shift): Avoid signed integer overflow.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41959 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 1 deletions

diff --git a/bignum.c b/bignum.c
index a20f8369fd..fb3954624c 100644
--- a/bignum.c
+++ b/bignum.c
@@ -5283,7 +5283,7 @@ static VALUE
 big_shift(VALUE x, long n)
 {
     if (n < 0)
-	return big_lshift(x, (unsigned long)-n);
+	return big_lshift(x, 1+(unsigned long)(-(n+1)));
     else if (n > 0)
 	return big_rshift(x, (unsigned long)n);
     return x;