diff --git a/stl/inc/random b/stl/inc/random
index 32be63fa7df..2acfaa5656b 100644
--- a/stl/inc/random
+++ b/stl/inc/random
@@ -4140,16 +4140,13 @@ private:
         _Ty _Rx0;
         _Ty _Rs;
         uniform_real<_Ty> _Dist(-1, 1);
-        for (;;) { // get a point inside unit circle
+        do { // get a point inside unit circle
             _Vx1 = _Dist(_Eng);
             _Vx2 = _Dist(_Eng);
             _Rs  = _Vx1 * _Vx1 + _Vx2 * _Vx2;
 
             // very small _Rs will overflow on pow(_Rx0, -_Ty{4} / _Par0._Nx)
-            if (_Rs < _Ty{1} && _Rs > _Ty{1e-12}) {
-                break;
-            }
-        }
+        } while (_Rs >= _Ty{1} || _Rs <= _Ty{1e-12});
         _Rx0 = _STD sqrt(_Rs);
         return _Vx1 * _STD sqrt(_Par0._Nx * (_STD pow(_Rx0, -_Ty{4} / _Par0._Nx) - _Ty{1}) / _Rs);
     }