Speed up rounding to byte test

unit_test/color_test.cc

 /*
  *  Copyright 2015 The LibYuv Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS. All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 205 matching lines @@
 
   /* YUV converted to ARGB. */
   J400ToARGB(orig_y, kWidth, orig_pixels, kWidth * 4, kWidth, kHeight);
 
   *b = orig_pixels[0];
   *g = orig_pixels[1];
   *r = orig_pixels[2];
 }
 
 // Pick a method for clamping.
-#define CLAMPMETHOD_IF 1
+//  #define CLAMPMETHOD_IF 1
 //  #define CLAMPMETHOD_TABLE 1
-//  #define CLAMPMETHOD_TERNARY 1
+#define CLAMPMETHOD_TERNARY 1
 //  #define CLAMPMETHOD_MASK 1
 
 // Pick a method for rounding.
-#define ROUND(f) static_cast<int>(f + 0.5)
+#define ROUND(f) static_cast<int>(f + 0.5f)
 //  #define ROUND(f) lrintf(f)
 //  #define ROUND(f) static_cast<int>(round(f))
 //  #define ROUND(f) _mm_cvt_ss2si(_mm_load_ss(&f))
 
 #if defined(CLAMPMETHOD_IF)
 static int RoundToByte(float f) {
   int i =  ROUND(f);
   if (i < 0) {
     i = 0;
   }
@@ skipping 64 matching lines @@
   int i = ROUND(f);
   i =  ((-(i) >> 31) & (i));  // clamp to 0.
   return (((255 - (i)) >> 31) | (i)) & 255;  // clamp to 255.
 }
 #endif
 
 #define RANDOM256(s) ((s & 1) ? ((s >> 1) ^ 0xb8) : (s >> 1))
 
 TEST_F(libyuvTest, TestRoundToByte) {
   int allb = 0;
+  int count = benchmark_width_ * benchmark_height_;
   for (int i = 0; i < benchmark_iterations_; ++i) {
-    for (int u2 = 0; u2 < 256; ++u2) {
-      for (int v2 = 0; v2 < 256; ++v2) {
-        for (int y2 = 0; y2 < 256; ++y2) {
-          int y = RANDOM256(y2);
-          int b = RoundToByte(y * 810.33 - 257);
-          allb |= b;
-        }
-      }
+    float f = (fastrand() & 255) * 3.14f - 260.f;
+    for (int j = 0; j < count; ++j) {
+      int b = RoundToByte(f);
+      f += 0.91f;
+      allb |= b;
     }
   }
   EXPECT_GE(allb, 0);
   EXPECT_LE(allb, 255);
 }
 
 static void YUVToRGBReference(int y, int u, int v, int* r, int* g, int* b) {
   *r = RoundToByte((y - 16) * 1.164 - (v - 128) * -1.596);
   *g = RoundToByte((y - 16) * 1.164 - (u - 128) * 0.391 - (v - 128) * 0.813);
   *b = RoundToByte((y - 16) * 1.164 - (u - 128) * -2.018);
@@ skipping 215 matching lines @@
     EXPECT_EQ(r0, r1);
     EXPECT_EQ(g0, g1);
     EXPECT_EQ(b0, b1);
     EXPECT_EQ(r0, r2);
     EXPECT_EQ(g0, g2);
     EXPECT_EQ(b0, b2);
   }
 }
 
 }  // namespace libyuv