diff --git a/ChangeLog b/ChangeLog
index 6ba3c7b6cd..0997df6c77 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+Mon Jul 16 15:00:45 2012  Tanaka Akira  <akr@fsij.org>
+
+	* internal.h (rb_big_float_cmp): declared.
+
+	* bignum.c (rb_big_float_cmp): extracted from rb_big_cmp and big_op.
+	  (rb_big_cmp): use rb_big_float_cmp.
+	  (big_op): ditto.
+
+	* numeric.c (flo_cmp): use rb_big_float_cmp.
+	  (flo_gt): ditto.
+	  (flo_ge): ditto.
+	  (flo_lt): ditto.
+	  (flo_le): ditto.
+
 Mon Jul 16 14:14:21 2012  Tanaka Akira  <akr@fsij.org>
 
 	* bignum.c (enum big_op_t): new type.
diff --git a/bignum.c b/bignum.c
index 43669db4a7..839a866ae9 100644
--- a/bignum.c
+++ b/bignum.c
@@ -1431,6 +1431,18 @@ rb_big_to_f(VALUE x)
     return DBL2NUM(rb_big2dbl(x));
 }
 
+VALUE
+rb_big_float_cmp(VALUE x, VALUE y)
+{
+    double a = RFLOAT_VALUE(y);
+
+    if (isinf(a)) {
+        if (a > 0.0) return INT2FIX(-1);
+        else return INT2FIX(1);
+    }
+    return rb_dbl_cmp(rb_big2dbl(x), a);
+}
+
 /*
  *  call-seq:
  *     big <=> numeric   -> -1, 0, +1 or nil
@@ -1456,15 +1468,7 @@ rb_big_cmp(VALUE x, VALUE y)
 	break;
 
       case T_FLOAT:
-	{
-	    double a = RFLOAT_VALUE(y);
-
-	    if (isinf(a)) {
-		if (a > 0.0) return INT2FIX(-1);
-		else return INT2FIX(1);
-	    }
-	    return rb_dbl_cmp(rb_big2dbl(x), a);
-	}
+        return rb_big_float_cmp(x, y);
 
       default:
 	return rb_num_coerce_cmp(x, y, rb_intern("<=>"));
@@ -1507,17 +1511,8 @@ big_op(VALUE x, VALUE y, enum big_op_t op)
 	break;
 
       case T_FLOAT:
-	{
-	    double a = RFLOAT_VALUE(y);
-
-	    if (isinf(a)) {
-		if (a > 0.0) rel = INT2FIX(-1);
-		else rel = INT2FIX(1);
-		break;
-	    }
-	    rel = rb_dbl_cmp(rb_big2dbl(x), a);
-	    break;
-	}
+        rel = rb_big_float_cmp(x, y);
+        break;
 
       default:
 	{
diff --git a/internal.h b/internal.h
index cc4a263694..d213539b25 100644
--- a/internal.h
+++ b/internal.h
@@ -49,6 +49,7 @@ VALUE rb_ary_cat(VALUE, const VALUE *, long);
 /* bignum.c */
 VALUE rb_big_fdiv(VALUE x, VALUE y);
 VALUE rb_big_uminus(VALUE x);
+VALUE rb_big_float_cmp(VALUE x, VALUE y);
 
 /* class.c */
 VALUE rb_obj_methods(int argc, VALUE *argv, VALUE obj);
diff --git a/numeric.c b/numeric.c
index 42e923fe5a..cf4fc3f181 100644
--- a/numeric.c
+++ b/numeric.c
@@ -1128,12 +1128,12 @@ flo_cmp(VALUE x, VALUE y)
 	break;
 
       case T_BIGNUM:
-	if (isinf(a)) {
-	    if (a > 0.0) return INT2FIX(1);
-	    else return INT2FIX(-1);
-	}
-	b = rb_big2dbl(y);
-	break;
+      {
+        VALUE rel = rb_big_float_cmp(y, x);
+        if (FIXNUM_P(rel))
+            return INT2FIX(-FIX2INT(rel));
+        return rel;
+      }
 
       case T_FLOAT:
 	b = RFLOAT_VALUE(y);
@@ -1173,8 +1173,12 @@ flo_gt(VALUE x, VALUE y)
 	break;
 
       case T_BIGNUM:
-	b = rb_big2dbl(y);
-	break;
+      {
+        VALUE rel = rb_big_float_cmp(y, x);
+        if (FIXNUM_P(rel))
+            return -FIX2INT(rel) > 0 ? Qtrue : Qfalse;
+        return Qfalse;
+      }
 
       case T_FLOAT:
 	b = RFLOAT_VALUE(y);
@@ -1212,8 +1216,12 @@ flo_ge(VALUE x, VALUE y)
 	break;
 
       case T_BIGNUM:
-	b = rb_big2dbl(y);
-	break;
+      {
+        VALUE rel = rb_big_float_cmp(y, x);
+        if (FIXNUM_P(rel))
+            return -FIX2INT(rel) >= 0 ? Qtrue : Qfalse;
+        return Qfalse;
+      }
 
       case T_FLOAT:
 	b = RFLOAT_VALUE(y);
@@ -1250,8 +1258,12 @@ flo_lt(VALUE x, VALUE y)
 	break;
 
       case T_BIGNUM:
-	b = rb_big2dbl(y);
-	break;
+      {
+        VALUE rel = rb_big_float_cmp(y, x);
+        if (FIXNUM_P(rel))
+            return -FIX2INT(rel) < 0 ? Qtrue : Qfalse;
+        return Qfalse;
+      }
 
       case T_FLOAT:
 	b = RFLOAT_VALUE(y);
@@ -1289,8 +1301,12 @@ flo_le(VALUE x, VALUE y)
 	break;
 
       case T_BIGNUM:
-	b = rb_big2dbl(y);
-	break;
+      {
+        VALUE rel = rb_big_float_cmp(y, x);
+        if (FIXNUM_P(rel))
+            return -FIX2INT(rel) <= 0 ? Qtrue : Qfalse;
+        return Qfalse;
+      }
 
       case T_FLOAT:
 	b = RFLOAT_VALUE(y);