Squashed 'third_party/abseil_cpp/' changes from 768eb2ca2..ccdbb5941

ccdbb5941 Export of internal Abseil changes
01f5f81f9 Export of internal Abseil changes
2c92bdc7c Export of internal Abseil changes
e7ebf9803 Export of internal Abseil changes
2eba343b5 Export of internal Abseil changes
a8b03d90e Export of internal Abseil changes
1d31b5c36 Export of internal Abseil changes
da3a87690 Export of internal Abseil changes
8faf20461 Exclude empty directories (#697)
2069dc796 Export of internal Abseil changes
4832bf6bf Added a BUILD file in root to expose license. (#695)
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33caf1097 Export of internal Abseil changes
cf1a02e2d Export of internal Abseil changes

git-subtree-dir: third_party/abseil_cpp
git-subtree-split: ccdbb5941f992fabda7eae3ce72f55efc17c826a

1 files changed, 132 insertions, 0 deletions

diff --git a/absl/base/optimization_test.cc b/absl/base/optimization_test.cc
new file mode 100644
index 000000000000..894b68f8f346
--- /dev/null
+++ b/absl/base/optimization_test.cc
@@ -0,0 +1,132 @@
+// Copyright 2020 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/base/optimization.h"
+
+#include "gtest/gtest.h"
+#include "absl/types/optional.h"
+
+namespace {
+
+// Tests for the ABSL_PREDICT_TRUE and ABSL_PREDICT_FALSE macros.
+// The tests only verify that the macros are functionally correct - i.e. code
+// behaves as if they weren't used. They don't try to check their impact on
+// optimization.
+
+TEST(PredictTest, PredictTrue) {
+  EXPECT_TRUE(ABSL_PREDICT_TRUE(true));
+  EXPECT_FALSE(ABSL_PREDICT_TRUE(false));
+  EXPECT_TRUE(ABSL_PREDICT_TRUE(1 == 1));
+  EXPECT_FALSE(ABSL_PREDICT_TRUE(1 == 2));
+
+  if (ABSL_PREDICT_TRUE(false)) ADD_FAILURE();
+  if (!ABSL_PREDICT_TRUE(true)) ADD_FAILURE();
+
+  EXPECT_TRUE(ABSL_PREDICT_TRUE(true) && true);
+  EXPECT_TRUE(ABSL_PREDICT_TRUE(true) || false);
+}
+
+TEST(PredictTest, PredictFalse) {
+  EXPECT_TRUE(ABSL_PREDICT_FALSE(true));
+  EXPECT_FALSE(ABSL_PREDICT_FALSE(false));
+  EXPECT_TRUE(ABSL_PREDICT_FALSE(1 == 1));
+  EXPECT_FALSE(ABSL_PREDICT_FALSE(1 == 2));
+
+  if (ABSL_PREDICT_FALSE(false)) ADD_FAILURE();
+  if (!ABSL_PREDICT_FALSE(true)) ADD_FAILURE();
+
+  EXPECT_TRUE(ABSL_PREDICT_FALSE(true) && true);
+  EXPECT_TRUE(ABSL_PREDICT_FALSE(true) || false);
+}
+
+TEST(PredictTest, OneEvaluation) {
+  // Verify that the expression is only evaluated once.
+  int x = 0;
+  if (ABSL_PREDICT_TRUE((++x) == 0)) ADD_FAILURE();
+  EXPECT_EQ(x, 1);
+  if (ABSL_PREDICT_FALSE((++x) == 0)) ADD_FAILURE();
+  EXPECT_EQ(x, 2);
+}
+
+TEST(PredictTest, OperatorOrder) {
+  // Verify that operator order inside and outside the macro behaves well.
+  // These would fail for a naive '#define ABSL_PREDICT_TRUE(x) x'
+  EXPECT_TRUE(ABSL_PREDICT_TRUE(1 && 2) == true);
+  EXPECT_TRUE(ABSL_PREDICT_FALSE(1 && 2) == true);
+  EXPECT_TRUE(!ABSL_PREDICT_TRUE(1 == 2));
+  EXPECT_TRUE(!ABSL_PREDICT_FALSE(1 == 2));
+}
+
+TEST(PredictTest, Pointer) {
+  const int x = 3;
+  const int *good_intptr = &x;
+  const int *null_intptr = nullptr;
+  EXPECT_TRUE(ABSL_PREDICT_TRUE(good_intptr));
+  EXPECT_FALSE(ABSL_PREDICT_TRUE(null_intptr));
+  // The following doesn't compile:
+  // EXPECT_TRUE(ABSL_PREDICT_FALSE(good_intptr));
+  // EXPECT_FALSE(ABSL_PREDICT_FALSE(null_intptr));
+}
+
+TEST(PredictTest, Optional) {
+  // Note: An optional's truth value is the value's existence, not its truth.
+  absl::optional<bool> has_value(false);
+  absl::optional<bool> no_value;
+  EXPECT_TRUE(ABSL_PREDICT_TRUE(has_value));
+  EXPECT_FALSE(ABSL_PREDICT_TRUE(no_value));
+  // The following doesn't compile:
+  // EXPECT_TRUE(ABSL_PREDICT_FALSE(has_value));
+  // EXPECT_FALSE(ABSL_PREDICT_FALSE(no_value));
+}
+
+class ImplictlyConvertibleToBool {
+ public:
+  explicit ImplictlyConvertibleToBool(bool value) : value_(value) {}
+  operator bool() const {  // NOLINT(google-explicit-constructor)
+    return value_;
+  }
+
+ private:
+  bool value_;
+};
+
+TEST(PredictTest, ImplicitBoolConversion) {
+  const ImplictlyConvertibleToBool is_true(true);
+  const ImplictlyConvertibleToBool is_false(false);
+  if (!ABSL_PREDICT_TRUE(is_true)) ADD_FAILURE();
+  if (ABSL_PREDICT_TRUE(is_false)) ADD_FAILURE();
+  if (!ABSL_PREDICT_FALSE(is_true)) ADD_FAILURE();
+  if (ABSL_PREDICT_FALSE(is_false)) ADD_FAILURE();
+}
+
+class ExplictlyConvertibleToBool {
+ public:
+  explicit ExplictlyConvertibleToBool(bool value) : value_(value) {}
+  explicit operator bool() const { return value_; }
+
+ private:
+  bool value_;
+};
+
+TEST(PredictTest, ExplicitBoolConversion) {
+  const ExplictlyConvertibleToBool is_true(true);
+  const ExplictlyConvertibleToBool is_false(false);
+  if (!ABSL_PREDICT_TRUE(is_true)) ADD_FAILURE();
+  if (ABSL_PREDICT_TRUE(is_false)) ADD_FAILURE();
+  // The following doesn't compile:
+  // if (!ABSL_PREDICT_FALSE(is_true)) ADD_FAILURE();
+  // if (ABSL_PREDICT_FALSE(is_false)) ADD_FAILURE();
+}
+
+}  // namespace