Export of internal Abseil changes

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1bc4d36e13fb9175ea8cdaa00213aa9d4417c669 by Andy Getzendanner <durandal@google.com>:

Fix pointer format specifier in documentation

Import of https://github.com/abseil/abseil-cpp/pull/614

PiperOrigin-RevId: 293227540

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c7b43b30493c4fb5f2ec3264672b08bfe1ea3709 by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 293160245

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64439365e2b4a0b5e51ae0a7dafdb15912402dfd by Shahriar Rouf <nafi@google.com>:

Add benchmarks for string_view: BM_CompareFirstOneLess and BM_CompareSecondOneLess.

PiperOrigin-RevId: 293031676

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b273b420cab24a6e3f487430987e09f4eb1caec4 by Greg Falcon <gfalcon@google.com>:

Remove an unreachable line from charconv.cc.

Fixes github issue #613.

PiperOrigin-RevId: 292980167

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70babb5f7a3d9fdd00a2b3085c3c2b9fe0265c79 by Gennadiy Rozental <rogeeff@google.com>:

Move GetFlag implementation into FlagImpl.

This change will allow us to hide details of GetFlag overloads inside implementation detais. Eventually we'll migrate to a different implementation. No semantic changes in this CL.

PiperOrigin-RevId: 292930847

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94bee7b7cc31e0167ee4b953281c1e78c96a574a by Abseil Team <absl-team@google.com>:

Clarification in absl::Exponential documentation.

PiperOrigin-RevId: 292912672

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d6916d30c5c1d3ee9ae46d69ec0a166a760c99c7 by Derek Mauro <dmauro@google.com>:

Make AtomicHook constant-initializable on Clang for Windows.

Only mark AtomicHook as constant-initializable on platforms where it
is actually constant-initializable.

PiperOrigin-RevId: 292655939
GitOrigin-RevId: 1bc4d36e13fb9175ea8cdaa00213aa9d4417c669
Change-Id: I090b231a0ca0d92868e494ab5b3fa86c902889d5

2 files changed, 34 insertions, 1 deletions

diff --git a/absl/strings/charconv.cc b/absl/strings/charconv.cc
index d9bc2dd20828..bdba768dcd6c 100644
--- a/absl/strings/charconv.cc
+++ b/absl/strings/charconv.cc
@@ -673,7 +673,6 @@ from_chars_result FromCharsImpl(const char* first, const char* last,
     EncodeResult(calculated, negative, &result, &value);
     return result;
   }
-  return result;
 }
 }  // namespace
 
diff --git a/absl/strings/string_view_benchmark.cc b/absl/strings/string_view_benchmark.cc
index f2e4214c5110..0d74e23e2fc9 100644
--- a/absl/strings/string_view_benchmark.cc
+++ b/absl/strings/string_view_benchmark.cc
@@ -160,11 +160,45 @@ void BM_CompareSame(benchmark::State& state) {
   absl::string_view b = y;
 
   for (auto _ : state) {
+    benchmark::DoNotOptimize(a);
+    benchmark::DoNotOptimize(b);
     benchmark::DoNotOptimize(a.compare(b));
   }
 }
 BENCHMARK(BM_CompareSame)->DenseRange(0, 3)->Range(4, 1 << 10);
 
+void BM_CompareFirstOneLess(benchmark::State& state) {
+  const int len = state.range(0);
+  std::string x(len, 'a');
+  std::string y = x;
+  y.back() = 'b';
+  absl::string_view a = x;
+  absl::string_view b = y;
+
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(a);
+    benchmark::DoNotOptimize(b);
+    benchmark::DoNotOptimize(a.compare(b));
+  }
+}
+BENCHMARK(BM_CompareFirstOneLess)->DenseRange(1, 3)->Range(4, 1 << 10);
+
+void BM_CompareSecondOneLess(benchmark::State& state) {
+  const int len = state.range(0);
+  std::string x(len, 'a');
+  std::string y = x;
+  x.back() = 'b';
+  absl::string_view a = x;
+  absl::string_view b = y;
+
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(a);
+    benchmark::DoNotOptimize(b);
+    benchmark::DoNotOptimize(a.compare(b));
+  }
+}
+BENCHMARK(BM_CompareSecondOneLess)->DenseRange(1, 3)->Range(4, 1 << 10);
+
 void BM_find_string_view_len_one(benchmark::State& state) {
   std::string haystack(state.range(0), '0');
   absl::string_view s(haystack);