numeric.c: 0 % Float::NAN returns Float::NAN

* numeric.c (flodivmod): all results are NaN if divisor is NaN.
  [fix GH-692]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47024 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Fri Aug  1 16:35:32 2014  Evan Miller  <evan@squareup.com>
+
+	* numeric.c (flodivmod): all results are NaN if divisor is NaN.
+	  [fix GH-692]
+
 Thu Aug 01 07:28:12 2014  Kenta Murata  <mrkn@mrkn.jp>
 
 	* ext/bigdecimal/bigdecimal.c: [DOC] Add description of

numeric.c

@@ -890,6 +890,12 @@ flodivmod(double x, double y, double *divp, double *modp)
 {
     double div, mod;
 
+    if (isnan(y)) {
+	/* y is NaN so all results are NaN */
+	if (modp) *modp = y;
+	if (divp) *divp = y;
+	return;
+    }
     if (y == 0.0) rb_num_zerodiv();
     if ((x == 0.0) || (isinf(y) && !isinf(x)))
         mod = x;
@@ -903,7 +909,7 @@ flodivmod(double x, double y, double *divp, double *modp)
 	mod = x - z * y;
 #endif
     }
-    if (isinf(x) && !isinf(y) && !isnan(y))
+    if (isinf(x) && !isinf(y))
 	div = x;
     else
 	div = (x - mod) / y;

test/ruby/test_float.rb

@@ -271,6 +271,12 @@ class TestFloat < Test::Unit::TestCase
     assert_raise(ZeroDivisionError, bug6048) { 42 % 0 }
   end
 
+  def test_modulo4
+    assert_predicate((0.0).modulo(Float::NAN), :nan?)
+    assert_predicate((1.0).modulo(Float::NAN), :nan?)
+    assert_predicate(Float::INFINITY.modulo(1), :nan?)
+  end
+
   def test_divmod2
     assert_equal([1.0, 0.0], 2.0.divmod(2))
     assert_equal([1.0, 0.0], 2.0.divmod((2**32).coerce(2).first))