avoid division by zero

* cvt(): use signbit() instead of 1/d < 0
* w_float(): ditto
* ruby_float_step_size(): unit==0 check shall be prior to divisions
* arith_seq_float_step_size(): ditto
* rb_big_divide(): same as r65642
* fix_divide(): ditto
* rb_big_fdiv_double(): ditto
* fix_fdiv_double(): ditto


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65751 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 6 insertions, 5 deletions

diff --git a/enumerator.c b/enumerator.c
index 466e064560..274583a3de 100644
--- a/enumerator.c
+++ b/enumerator.c
@@ -2790,15 +2790,16 @@ static double
 arith_seq_float_step_size(double beg, double end, double step, int excl)
 {
     double const epsilon = DBL_EPSILON;
-    double n = (end - beg) / step;
-    double err = (fabs(beg) + fabs(end) + fabs(end - beg)) / fabs(step) * epsilon;
+    double n, err;
 
-    if (isinf(step)) {
-        return step > 0 ? beg <= end : beg >= end;
-    }
     if (step == 0) {
         return HUGE_VAL;
     }
+    n = (end - beg) / step;
+    err = (fabs(beg) + fabs(end) + fabs(end - beg)) / fabs(step) * epsilon;
+    if (isinf(step)) {
+        return step > 0 ? beg <= end : beg >= end;
+    }
     if (err > 0.5) err = 0.5;
     if (excl) {
         if (n <= 0) return 0;