[builtins] Introduce proper Float64Log2 and Float64Log10 operators.

test/unittests/base/ieee754-unittest.cc

 // Copyright 2016 the V8 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.
 
 #include <limits>
 
 #include "src/base/ieee754.h"
 #include "src/base/macros.h"
 #include "testing/gmock-support.h"
 #include "testing/gtest-support.h"
@@ skipping 73 matching lines @@
   EXPECT_EQ(2.3978952727983707, log1p(10));
   EXPECT_EQ(36.841361487904734, log1p(10e15));
   EXPECT_EQ(37.08337388996168, log1p(12738099905822720));
   EXPECT_EQ(37.08336444902049, log1p(12737979646738432));
   EXPECT_EQ(1.3862943611198906, log1p(3));
   EXPECT_EQ(1.3862945995384413, log1p(3 + 9.5367431640625e-7));
   EXPECT_EQ(0.5596157879354227, log1p(0.75));
   EXPECT_EQ(0.8109302162163288, log1p(1.25));
 }
 
+TEST(Ieee754, Log2) {
+  EXPECT_THAT(log2(std::numeric_limits<double>::quiet_NaN()), IsNaN());
+  EXPECT_THAT(log2(std::numeric_limits<double>::signaling_NaN()), IsNaN());
+  EXPECT_THAT(log2(-std::numeric_limits<double>::infinity()), IsNaN());
+  EXPECT_THAT(log2(-1.0), IsNaN());
+  EXPECT_EQ(-std::numeric_limits<double>::infinity(), log2(0.0));
+  EXPECT_EQ(-std::numeric_limits<double>::infinity(), log2(-0.0));
+  EXPECT_EQ(std::numeric_limits<double>::infinity(),
+            log2(std::numeric_limits<double>::infinity()));
+}
+
+TEST(Ieee754, Log10) {
+  EXPECT_THAT(log10(std::numeric_limits<double>::quiet_NaN()), IsNaN());
+  EXPECT_THAT(log10(std::numeric_limits<double>::signaling_NaN()), IsNaN());
+  EXPECT_THAT(log10(-std::numeric_limits<double>::infinity()), IsNaN());
+  EXPECT_THAT(log10(-1.0), IsNaN());
+  EXPECT_EQ(-std::numeric_limits<double>::infinity(), log10(0.0));
+  EXPECT_EQ(-std::numeric_limits<double>::infinity(), log10(-0.0));
+  EXPECT_EQ(std::numeric_limits<double>::infinity(),
+            log10(std::numeric_limits<double>::infinity()));
+  EXPECT_EQ(3.0, log10(1000.0));
+  EXPECT_EQ(14.0, log10(100000000000000));  // log10(10 ^ 14)
+  EXPECT_EQ(3.7389561269540406, log10(5482.2158));
+  EXPECT_EQ(14.661551142893833, log10(458723662312872.125782332587));
+  EXPECT_EQ(-0.9083828622192334, log10(0.12348583358871));
+}
+
 }  // namespace ieee754
 }  // namespace base
 }  // namespace v8