Export of internal Abseil changes

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dab5caab05d89d03066ef92584660688595a3aaf by Mark Barolak <mbar@google.com>:

Add absl::Status and absl::StatusOr to absl/README.md

Import of https://github.com/abseil/abseil-cpp/pull/863

PiperOrigin-RevId: 347857368

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1ca3c7a96417cd6e6d62f4dc36fd5ddaa61cfa20 by Chris Kennelly <ckennelly@google.com>:

Leverage integer power-of-2 functions and bit counting library in Abseil.

PiperOrigin-RevId: 347816486

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e5cbe05879fd65dce7875e2e0105331a1615d89b by Chris Kennelly <ckennelly@google.com>:

Mitigate narrowing warning on MSVC.

If sizeof(x) <= sizeof(uint32_t), no truncation occurs when casting to
uint32_t, but the compiler cannot always determine this.

PiperOrigin-RevId: 347696526

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079dff64cb175d282d9e22dfb4a522199ffdae2e by Benjamin Barenblat <bbaren@google.com>:

Avoid libgcc -NaN narrowing bug

When testing -NaN parsing, avoid narrowing -NaN from double to float.
This avoids a bug in libgcc
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98251).

PiperOrigin-RevId: 347654751

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2e78a7634865aeef6765e1f447e96cf8d9985059 by Chris Kennelly <ckennelly@google.com>:

Mark popcount helpers as inline.

These are conditionally constexpr, so we need to add inline to cover the
non-constexpr builds to avoid ODR violations.

PiperOrigin-RevId: 347620138

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437fbb363aea1654179f102dcdd607ec33c1af1e by Chris Kennelly <ckennelly@google.com>:

Use explicit narrowing cast.

This is never invoked in practice, but compilers with -Wimplicit-int-conversion
may trigger when sizeof(T) > sizeof(uint16_t) prior to determining this never
runs.

PiperOrigin-RevId: 347609857
GitOrigin-RevId: dab5caab05d89d03066ef92584660688595a3aaf
Change-Id: I6296ddffe7ec646f8ce121138f21e1e85a2cff4b

1 files changed, 5 insertions, 5 deletions

diff --git a/absl/strings/charconv.cc b/absl/strings/charconv.cc
index 3613a652..b8674c28 100644
--- a/absl/strings/charconv.cc
+++ b/absl/strings/charconv.cc
@@ -20,7 +20,7 @@
 #include <cstring>
 
 #include "absl/base/casts.h"
-#include "absl/base/internal/bits.h"
+#include "absl/numeric/bits.h"
 #include "absl/numeric/int128.h"
 #include "absl/strings/internal/charconv_bigint.h"
 #include "absl/strings/internal/charconv_parse.h"
@@ -242,11 +242,11 @@ struct CalculatedFloat {
 
 // Returns the bit width of the given uint128.  (Equivalently, returns 128
 // minus the number of leading zero bits.)
-int BitWidth(uint128 value) {
+unsigned BitWidth(uint128 value) {
   if (Uint128High64(value) == 0) {
-    return 64 - base_internal::CountLeadingZeros64(Uint128Low64(value));
+    return static_cast<unsigned>(bit_width(Uint128Low64(value)));
   }
-  return 128 - base_internal::CountLeadingZeros64(Uint128High64(value));
+  return 128 - countl_zero(Uint128High64(value));
 }
 
 // Calculates how far to the right a mantissa needs to be shifted to create a
@@ -519,7 +519,7 @@ CalculatedFloat CalculateFromParsedHexadecimal(
     const strings_internal::ParsedFloat& parsed_hex) {
   uint64_t mantissa = parsed_hex.mantissa;
   int exponent = parsed_hex.exponent;
-  int mantissa_width = 64 - base_internal::CountLeadingZeros64(mantissa);
+  auto mantissa_width = static_cast<unsigned>(bit_width(mantissa));
   const int shift = NormalizedShiftSize<FloatType>(mantissa_width, exponent);
   bool result_exact;
   exponent += shift;