Revert "* numeric.c (ruby_float_step): Avoid error on i386 and amd64."

r33282 challenged the precision of floating point but:
* Ruby keeps it as platform dependent
* amd64 won't get this issue because compilers for amd64 uses SSE2 to
  calculate floating point numbers instead of x87 FPU.
* this change won't fix the issue under -O
* this commit has no test for the changed behavior

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@33284 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,8 +1,3 @@
-Fri Sep 16 02:05:44 2011  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
-
-	* numeric.c (ruby_float_step): Avoid error on i386 and amd64.
-	  Patch by Vit Ondruch. Issue #4576.
-
 Thu Sep 15 11:39:43 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* gc.c (mark_entry, mark_key, mark_keyvalue): adjust callback

numeric.c

@@ -1683,7 +1683,6 @@ ruby_float_step(VALUE from, VALUE to, VALUE step, int excl)
 	double unit = NUM2DBL(step);
 	double n = (end - beg)/unit;
 	double err = (fabs(beg) + fabs(end) + fabs(end-beg)) / fabs(unit) * epsilon;
-	double im = 0.0;
 	long i;
 
 	if (isinf(unit)) {
@@ -1692,8 +1691,7 @@ ruby_float_step(VALUE from, VALUE to, VALUE step, int excl)
 	else {
 	    if (err>0.5) err=0.5;
 	    n = floor(n + err);
-	    im = ((long)n)*unit+beg;
-	    if (!excl || im < end) n++;
+	    if (!excl || ((long)n)*unit+beg < end) n++;
 	    for (i=0; i<n; i++) {
 		rb_yield(DBL2NUM(i*unit+beg));
 	    }