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author | Aditya Kumar <hiraditya@msn.com> | 2017-06-14 23:17:45 +0000 |
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committer | Aditya Kumar <hiraditya@msn.com> | 2017-06-14 23:17:45 +0000 |
commit | aa356d6b866bdfbf143e3dc5dce069ff6dc080c4 (patch) | |
tree | 5b74bc2746be8b36da7dfae183a194422501094f /benchmarks | |
parent | 405af58e6be6dae38c9ddd0dff6316e541df96b7 (diff) | |
download | libcxx-aa356d6b866bdfbf143e3dc5dce069ff6dc080c4.tar.gz |
[locale] Avoid copy of __atoms when char_type is char
The function num_get<_CharT>::stage2_int_prep makes unnecessary copy of src
into atoms when char_type is char. This can be avoided by creating
a switch on type and just returning __src when char_type is char.
Added the test case to demonstrate performance improvement.
In order to avoid ABI incompatibilities, the changes are guarded
with a macro _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
Differential Revision: https://reviews.llvm.org/D30268
Reviewed by: EricWF
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@305427 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'benchmarks')
-rw-r--r-- | benchmarks/stringstream.bench.cpp | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/benchmarks/stringstream.bench.cpp b/benchmarks/stringstream.bench.cpp new file mode 100644 index 000000000..6023cf775 --- /dev/null +++ b/benchmarks/stringstream.bench.cpp @@ -0,0 +1,38 @@ +#include "benchmark/benchmark_api.h" + +#include <sstream> +double __attribute__((noinline)) istream_numbers(); + +double istream_numbers() { + const char *a[] = { + "-6 69 -71 2.4882e-02 -100 101 -2.00005 5000000 -50000000", + "-25 71 7 -9.3262e+01 -100 101 -2.00005 5000000 -50000000", + "-14 53 46 -6.7026e-02 -100 101 -2.00005 5000000 -50000000" + }; + + int a1, a2, a3, a4, a5, a6, a7; + double f1 = 0.0, f2 = 0.0, q = 0.0; + for (int i=0; i < 3; i++) { + std::istringstream s(a[i]); + s >> a1 + >> a2 + >> a3 + >> f1 + >> a4 + >> a5 + >> f2 + >> a6 + >> a7; + q += (a1 + a2 + a3 + a4 + a5 + a6 + a7 + f1 + f2)/1000000; + } + return q; +} + +static void BM_Istream_numbers(benchmark::State &state) { + double i = 0; + while (state.KeepRunning()) + benchmark::DoNotOptimize(i += istream_numbers()); +} + +BENCHMARK(BM_Istream_numbers)->RangeMultiplier(2)->Range(1024, 4096); +BENCHMARK_MAIN() |