nobu	2016-12-28 13:40:58 +0900 (Wed, 28 Dec 2016)

  New Revision: 57227

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=57227

  Log:
    numeric.c: reduce fdiv
    
    * numeric.c (rb_int_fdiv_double): reduce first for more precise
      result.  [ruby-core:78886] [Bug #13078]

  Modified files:
    trunk/internal.h
    trunk/numeric.c
    trunk/test/ruby/test_rational.rb
Index: numeric.c
===================================================================
--- numeric.c	(revision 57226)
+++ numeric.c	(revision 57227)
@@ -3614,6 +3614,13 @@ fix_fdiv_double(VALUE x, VALUE y) https://github.com/ruby/ruby/blob/trunk/numeric.c#L3614
 double
 rb_int_fdiv_double(VALUE x, VALUE y)
 {
+    if (RB_INTEGER_TYPE_P(y) && !FIXNUM_ZERO_P(y)) {
+	VALUE gcd = rb_gcd(x, y);
+	if (!FIXNUM_ZERO_P(gcd)) {
+	    x = rb_int_idiv(x, gcd);
+	    y = rb_int_idiv(y, gcd);
+	}
+    }
     if (FIXNUM_P(x)) {
         return fix_fdiv_double(x, y);
     }
Index: internal.h
===================================================================
--- internal.h	(revision 57226)
+++ internal.h	(revision 57227)
@@ -1682,6 +1682,7 @@ VALUE rb_execarg_extract_options(VALUE e https://github.com/ruby/ruby/blob/trunk/internal.h#L1682
 void rb_execarg_setenv(VALUE execarg_obj, VALUE env);
 
 /* rational.c (export) */
+VALUE rb_gcd(VALUE x, VALUE y);
 VALUE rb_gcd_normal(VALUE self, VALUE other);
 #if defined(HAVE_LIBGMP) && defined(HAVE_GMP_H)
 VALUE rb_gcd_gmp(VALUE x, VALUE y);
Index: test/ruby/test_rational.rb
===================================================================
--- test/ruby/test_rational.rb	(revision 57226)
+++ test/ruby/test_rational.rb	(revision 57227)
@@ -905,6 +905,13 @@ class Rational_Test < Test::Unit::TestCa https://github.com/ruby/ruby/blob/trunk/test/ruby/test_rational.rb#L905
     assert_equal(5000000000.0, 10000000000.fdiv(2))
     assert_equal(0.5, 1.0.fdiv(2))
     assert_equal(0.25, Rational(1,2).fdiv(2))
+
+    a = 0xa42fcabf_c51ce400_00001000_00000000_00000000_00000000_00000000_00000000
+    b = 1<<1074
+    assert_equal(Rational(a, b).to_f, a.fdiv(b))
+    a = 3
+    b = 0x20_0000_0000_0001
+    assert_equal(Rational(a, b).to_f, a.fdiv(b))
   end
 
   def test_ruby19

--
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