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authornobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2016-08-02 12:40:51 +0000
committernobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2016-08-02 12:40:51 +0000
commit83cfc94563c3f5eb0339f4cab280e5219a179a0c (patch)
tree84456645fc0b9232878993c38995c2b3a2e80696
parentaa8e9c63ad0300df0eed07c3fe4f19d859a63673 (diff)
math.c: tanh overflow
* math.c (tanh): check overflows, and return +-1.0. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55798 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
-rw-r--r--math.c4
-rw-r--r--test/ruby/test_math.rb2
2 files changed, 5 insertions, 1 deletions
diff --git a/math.c b/math.c
index a781167..eefcec3 100644
--- a/math.c
+++ b/math.c
@@ -283,7 +283,9 @@ math_sinh(VALUE obj, VALUE x)
double
tanh(double x)
{
- return sinh(x) / cosh(x);
+ const double c = cosh(x);
+ if (!isinf(c)) return sinh(x) / c;
+ return x > 0 ? 1.0 : -1.0;
}
#endif
diff --git a/test/ruby/test_math.rb b/test/ruby/test_math.rb
index ac9ab3c..f226287 100644
--- a/test/ruby/test_math.rb
+++ b/test/ruby/test_math.rb
@@ -111,6 +111,8 @@ class TestMath < Test::Unit::TestCase
check(Math.sinh(0) / Math.cosh(0), Math.tanh(0))
check(Math.sinh(1) / Math.cosh(1), Math.tanh(1))
check(Math.sinh(2) / Math.cosh(2), Math.tanh(2))
+ check(+1.0, Math.tanh(+1000.0))
+ check(-1.0, Math.tanh(-1000.0))
end
def test_acosh