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diff --git a/third_party/aom/test/log2_test.cc b/third_party/aom/test/log2_test.cc
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+++ b/third_party/aom/test/log2_test.cc
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+/*
+ * Copyright (c) 2018, Alliance for Open Media. All rights reserved
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+
+#include <math.h>
+
+#include "aom_ports/bitops.h"
+#include "av1/common/entropymode.h"
+#include "third_party/googletest/src/googletest/include/gtest/gtest.h"
+
+TEST(Log2Test, GetMsb) {
+  // Test small numbers exhaustively.
+  for (unsigned int n = 1; n < 10000; n++) {
+    EXPECT_EQ(get_msb(n), static_cast<int>(floor(log2(n))));
+  }
+
+  // Test every power of 2 and the two adjacent numbers.
+  for (int exponent = 2; exponent < 32; exponent++) {
+    const unsigned int power_of_2 = 1U << exponent;
+    EXPECT_EQ(get_msb(power_of_2 - 1), exponent - 1);
+    EXPECT_EQ(get_msb(power_of_2), exponent);
+    EXPECT_EQ(get_msb(power_of_2 + 1), exponent);
+  }
+}
+
+TEST(Log2Test, Av1CeilLog2) {
+  // Test small numbers exhaustively.
+  EXPECT_EQ(av1_ceil_log2(0), 0);
+  for (int n = 1; n < 10000; n++) {
+    EXPECT_EQ(av1_ceil_log2(n), static_cast<int>(ceil(log2(n))));
+  }
+
+  // Test every power of 2 and the two adjacent numbers.
+  for (int exponent = 2; exponent < 31; exponent++) {
+    const int power_of_2 = 1 << exponent;
+    EXPECT_EQ(av1_ceil_log2(power_of_2 - 1), exponent);
+    EXPECT_EQ(av1_ceil_log2(power_of_2), exponent);
+    // The current implementation of av1_ceil_log2 only works up to 2^30.
+    if (exponent < 30) {
+      EXPECT_EQ(av1_ceil_log2(power_of_2 + 1), exponent + 1);
+    }
+  }
+}