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authorGravatar Abseil Team <absl-team@google.com>2021-01-29 12:09:30 -0800
committerGravatar CJ Johnson <johnsoncj@google.com>2021-01-29 15:12:57 -0500
commita9a49560208484f1f99efdde889da6147e8722fe (patch)
tree72b0dbfed7927df49820ce1a99a0db86aaafc5cf /absl/base/config.h
parentaf39e133059928cfcdeea0592434720897f20173 (diff)
Export of internal Abseil changes
-- c68f1886f5e8fd90eb0c2d2e68feaf00a7cdacda by CJ Johnson <johnsoncj@google.com>: Introduce absl::Cleanup to the OSS repo PiperOrigin-RevId: 354583156 -- 17030cf388e10f7eb959e3e566326d1072ce392e by Abseil Team <absl-team@google.com>: Internal change only PiperOrigin-RevId: 354574953 -- e979d7236d4f3252e79ddda6739b67a9a326bf6d by CJ Johnson <johnsoncj@google.com>: Internal change PiperOrigin-RevId: 354545297 -- 7ea02b3783f7f49ef97d86a8f6580a19cc57df14 by Abseil Team <absl-team@google.com>: Pre-allocate memory for vectors where the size is known. PiperOrigin-RevId: 354344576 -- 9246c7cb11f1d6444f79ebe25acc69a8a9b870e0 by Matt Kulukundis <kfm@google.com>: Add support for Elbrus 2000 (e2k) Import of https://github.com/abseil/abseil-cpp/pull/889 PiperOrigin-RevId: 354344013 -- 0fc93d359cc1fb307552e917b37b7b2e7eed822f by Abseil Team <absl-team@google.com>: Integrate CordRepRing logic into cord (but do not enable it) PiperOrigin-RevId: 354312238 -- eda05622f7da71466723acb33403f783529df24b by Abseil Team <absl-team@google.com>: Protect ignore diagnostic with "__has_warning". PiperOrigin-RevId: 354112334 -- 47716c5d8fb10efa4fdd801d28bac414c6f8ec32 by Abseil Team <absl-team@google.com>: Rearrange InlinedVector copy constructor and destructor to treat a few special cases inline and then tail-call a non-inlined routine for the rest. In particular, we optimize for empty vectors in both cases. Added a couple of benchmarks that copy either an InlVec<int64> or an InlVec<InlVec<int64>>. Speed difference: ``` BM_CopyTrivial/0 0.92ns +- 0% 0.47ns +- 0% -48.91% (p=0.000 n=11+12) BM_CopyTrivial/1 0.92ns +- 0% 1.15ns +- 0% +25.00% (p=0.000 n=10+9) BM_CopyTrivial/8 8.57ns +- 0% 10.72ns +- 1% +25.16% (p=0.000 n=10+12) BM_CopyNonTrivial/0 3.21ns +- 0% 0.70ns +- 0% -78.23% (p=0.000 n=12+10) BM_CopyNonTrivial/1 5.88ns +- 1% 5.51ns +- 0% -6.28% (p=0.000 n=10+8) BM_CopyNonTrivial/8 21.5ns +- 1% 15.2ns +- 2% -29.23% (p=0.000 n=12+12) ``` Note: the slowdowns are a few cycles which is expected given the procedure call added in that case. We decided this is a good tradeoff given the code size reductions and the more significant speedups for empty vectors. Size difference (as measured by nm): ``` BM_CopyTrivial from 1048 bytes to 326 bytes. BM_CopyNonTrivial from 749 bytes to 470 bytes. ``` Code size for a large binary drops by ~500KB (from 349415719 to 348906015 348906191). All of the benchmarks that showed a significant difference: Ones that improve with this CL: ``` BM_CopyNonTrivial/0 3.21ns +- 0% 0.70ns +- 0% -78.23% (p=0.000 n=12+10) BM_InlinedVectorFillString/0 0.93ns +- 0% 0.24ns +- 0% -74.19% (p=0.000 n=12+10) BM_InlinedVectorAssignments/1 10.5ns +- 0% 4.1ns +- 0% -60.64% (p=0.000 n=11+10) BM_InlinedVectorAssignments/2 10.7ns +- 0% 4.4ns +- 0% -59.08% (p=0.000 n=11+11) BM_CopyTrivial/0 0.92ns +- 0% 0.47ns +- 0% -48.91% (p=0.000 n=11+12) BM_CopyNonTrivial/8 21.5ns +- 1% 15.2ns +- 2% -29.23% (p=0.000 n=12+12) BM_StdVectorEmpty 0.47ns +- 1% 0.35ns +- 0% -24.73% (p=0.000 n=12+12) BM_StdVectorSize 0.46ns +- 2% 0.35ns +- 0% -24.32% (p=0.000 n=12+12) BM_SwapElements<LargeCopyableOnly>/0 3.44ns +- 0% 2.76ns +- 1% -19.83% (p=0.000 n=11+11) BM_InlinedVectorFillRange/256 20.7ns +- 1% 17.8ns +- 0% -14.08% (p=0.000 n=12+9) BM_CopyNonTrivial/1 5.88ns +- 1% 5.51ns +- 0% -6.28% (p=0.000 n=10+8) BM_SwapElements<LargeCopyableMovable>/1 4.19ns +- 0% 3.95ns +- 1% -5.63% (p=0.000 n=11+12) BM_SwapElements<LargeCopyableMovableSwappable>/1 4.18ns +- 0% 3.99ns +- 0% -4.70% (p=0.000 n=9+11) BM_SwapElements<LargeCopyableMovable>/0 2.41ns +- 0% 2.31ns +- 0% -4.45% (p=0.000 n=12+12) BM_InlinedVectorFillRange/64 8.25ns +- 0% 8.04ns +- 0% -2.51% (p=0.000 n=12+11) BM_SwapElements<LargeCopyableOnly>/1 82.4ns +- 0% 81.5ns +- 0% -1.06% (p=0.000 n=12+12) ``` Ones that get worse with this CL: ``` BM_CopyTrivial/1 0.92ns +- 0% 1.15ns +- 0% +25.00% (p=0.000 n=10+9) BM_CopyTrivial/8 8.57ns +- 0% 10.72ns +- 1% +25.16% (p=0.000 n=10+12) BM_SwapElements<LargeCopyableMovableSwappable>/512 1.48ns +- 1% 1.66ns +- 1% +11.88% (p=0.000 n=12+12) BM_InlinedVectorFillString/1 11.5ns +- 0% 12.8ns +- 1% +11.62% (p=0.000 n=12+11) BM_SwapElements<LargeCopyableMovableSwappable>/64 1.48ns +- 2% 1.66ns +- 1% +11.66% (p=0.000 n=12+11) BM_SwapElements<LargeCopyableMovableSwappable>/1k 1.48ns +- 1% 1.65ns +- 2% +11.32% (p=0.000 n=12+12) BM_SwapElements<LargeCopyableMovable>/512 1.48ns +- 2% 1.58ns +- 4% +6.62% (p=0.000 n=11+12) BM_SwapElements<LargeCopyableMovable>/1k 1.49ns +- 2% 1.58ns +- 3% +6.05% (p=0.000 n=12+12) BM_SwapElements<LargeCopyableMovable>/64 1.48ns +- 2% 1.57ns +- 4% +6.04% (p=0.000 n=11+12) BM_InlinedVectorFillRange/1 4.81ns +- 0% 5.05ns +- 0% +4.83% (p=0.000 n=11+11) BM_InlinedVectorFillString/8 79.4ns +- 1% 83.1ns +- 1% +4.64% (p=0.000 n=10+12) BM_StdVectorFillString/1 16.3ns +- 0% 16.6ns +- 0% +2.13% (p=0.000 n=11+8) ``` PiperOrigin-RevId: 353906786 -- 8e26518b3cec9c598e5e9573c46c3bd1b03a67ef by Abseil Team <absl-team@google.com>: Internal change PiperOrigin-RevId: 353737330 -- f206ae0983e58c9904ed8b8f05f9caf564a446be by Matt Kulukundis <kfm@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 353682256 GitOrigin-RevId: c68f1886f5e8fd90eb0c2d2e68feaf00a7cdacda Change-Id: I5790c1036c4f543c701d1039848fabf7ae881ad8
Diffstat (limited to 'absl/base/config.h')
-rw-r--r--absl/base/config.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/absl/base/config.h b/absl/base/config.h
index f6ddf0c5..3d6aa178 100644
--- a/absl/base/config.h
+++ b/absl/base/config.h
@@ -722,4 +722,13 @@ static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
#define ABSL_HAVE_ADDRESS_SANITIZER 1
#endif
+// ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION
+//
+// Class template argument deduction is a language feature added in C++17.
+#ifdef ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION
+#error "ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION cannot be directly set."
+#elif defined(__cpp_deduction_guides)
+#define ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION 1
+#endif
+
#endif // ABSL_BASE_CONFIG_H_
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