math.c: optimization for Bignum

* math.c (num2dbl_with_to_f): make faster when Bignum passed by
  direct conversion using rb_big2dbl().  [Feature #10800]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49449 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 32 insertions, 7 deletions

diff --git a/math.c b/math.c
index 3f0b11e344..5d4c2bbea5 100644
--- a/math.c
+++ b/math.c
@@ -26,13 +26,38 @@ static ID id_to_f;
 VALUE rb_mMath;
 VALUE rb_eMathDomainError;
 
-#define fix_to_f_optimizable() rb_method_basic_definition_p(rb_cFixnum, id_to_f)
-#define Get_Float(x) \
-    ((RB_TYPE_P((x), T_FLOAT) ? (void)0 : ((x) = rb_to_float(x))), RFLOAT_VALUE(x))
-#define Get_Double(x) \
-    (FIXNUM_P(x) && fix_to_f_optimizable() ? \
-     (double)FIX2LONG(x) : \
-     Get_Float(x))
+static inline int
+basic_to_f_p(VALUE klass)
+{
+    return rb_method_basic_definition_p(klass, id_to_f);
+}
+
+static inline double
+num2dbl_with_to_f(VALUE num)
+{
+    if (SPECIAL_CONST_P(num)) {
+	if (FIXNUM_P(num)) {
+	    if (basic_to_f_p(rb_cFixnum))
+		return (double)FIX2LONG(num);
+	}
+	else if (FLONUM_P(num)) {
+	    return RFLOAT_VALUE(num);
+	}
+    }
+    else {
+	switch (BUILTIN_TYPE(num)) {
+	  case T_FLOAT:
+	    return RFLOAT_VALUE(num);
+	  case T_BIGNUM:
+	    if (basic_to_f_p(rb_cBignum))
+		return rb_big2dbl(num);
+	    break;
+	}
+    }
+    return RFLOAT_VALUE(rb_to_float(num));
+}
+
+#define Get_Double(x) num2dbl_with_to_f(x)
 
 #define domain_error(msg) \
     rb_raise(rb_eMathDomainError, "Numerical argument is out of domain - " #msg)