Add sk_float_rsqrt with SSE + NEON fast paths.

tests/PointTest.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 // Unit tests for src/core/SkPoint.cpp and its header
 
 #include "SkPoint.h"
@@ skipping 99 matching lines @@
     SkPoint pt = { SkFloatToScalar(1.0e-37f), SkFloatToScalar(1.0e-37f) };
     SkPoint copy = pt;
 
     REPORTER_ASSERT(reporter, 0 == SkPoint::Normalize(&pt));
     REPORTER_ASSERT(reporter, pt == copy);  // pt is unchanged
 
     REPORTER_ASSERT(reporter, !pt.setLength(SK_Scalar1));
     REPORTER_ASSERT(reporter, pt == copy);  // pt is unchanged
 }
 
-static void PointTest(skiatest::Reporter* reporter) {
+#include "TestClassDef.h"
+DEF_TEST(Point, reporter) {
     test_casts(reporter);
 
     static const struct {
         SkScalar fX;
         SkScalar fY;
         SkScalar fLength;
     } gRec[] = {
         { SkIntToScalar(3), SkIntToScalar(4), SkIntToScalar(5) },
         { SkFloatToScalar(0.6f), SkFloatToScalar(0.8f), SK_Scalar1 },
     };
 
     for (size_t i = 0; i < SK_ARRAY_COUNT(gRec); ++i) {
         test_length(reporter, gRec[i].fX, gRec[i].fY, gRec[i].fLength);
     }
 
     test_underflow(reporter);
     test_overflow(reporter);
 }
 
-#include "TestClassDef.h"
-DEFINE_TESTCLASS("Point", PointTestClass, PointTest)
+DEF_TEST(Point_setLengthFast, reporter) {
+    // Scale a (1,1) point to a bunch of different lengths,
+    // making sure the slow and fast paths are within 0.1%.
+    const float tests[] = { 1.0f, 0.0f, 1.0e-37f, 3.4e38f, 42.0f, 0.00012f };
+
+    const SkPoint kOne = {1.0f, 1.0f};
+    for (unsigned i = 0; i < SK_ARRAY_COUNT(tests); i++) {
+        SkPoint slow = kOne, fast = kOne;
+
+        slow.setLength(tests[i]);
+        fast.setLengthFast(tests[i]);
+
+        if (slow.length() < FLT_MIN && fast.length() < FLT_MIN) continue;
+
+        SkScalar ratio = slow.length() / fast.length();
+        REPORTER_ASSERT(reporter, ratio > 0.999f);
+        REPORTER_ASSERT(reporter, ratio < 1.001f);
+    }
+}