Clarify iOS flush-to-zero status.

src/core/SkPoint.cpp

 
 /*
  * Copyright 2008 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkMathPriv.h"
@@ skipping 143 matching lines @@
 
     float scale;
     if (SkScalarIsFinite(mag2)) {
         scale = length / sk_float_sqrt(mag2);
     } else {
         // our mag2 step overflowed to infinity, so use doubles instead.
         // much slower, but needed when x or y are very large, other wise we
         // divide by inf. and return (0,0) vector.
         double xx = x;
         double yy = y;
-    #ifdef SK_DISCARD_DENORMALIZED_FOR_SPEED
+    #ifdef SK_CPU_FLUSH_TO_ZERO
         // The iOS ARM processor discards small denormalized numbers to go faster.
         // Casting this to a float would cause the scale to go to zero. Keeping it
         // as a double for the multiply keeps the scale non-zero.
         double dscale = length / sqrt(xx * xx + yy * yy);
         fX = x * dscale;
         fY = y * dscale;
         return true;
     #else
         scale = (float)(length / sqrt(xx * xx + yy * yy));
     #endif
@@ skipping 81 matching lines @@
         return v.lengthSqd();
     } else if (uDotV > uLengthSqd) {
         return b.distanceToSqd(*this);
     } else {
         SkScalar det = u.cross(v);
         SkScalar temp = det / uLengthSqd;
         temp *= det;
         return temp;
     }
 }