[libcxx] r305427 - [locale] Avoid copy of __atoms when char_type is char
Aditya Kumar via cfe-commits
cfe-commits at lists.llvm.org
Wed Jun 14 16:17:45 PDT 2017
Author: hiraditya
Date: Wed Jun 14 18:17:45 2017
New Revision: 305427
URL: http://llvm.org/viewvc/llvm-project?rev=305427&view=rev
Log:
[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
Added:
libcxx/trunk/benchmarks/stringstream.bench.cpp
Modified:
libcxx/trunk/include/__config
libcxx/trunk/include/locale
Added: libcxx/trunk/benchmarks/stringstream.bench.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/benchmarks/stringstream.bench.cpp?rev=305427&view=auto
==============================================================================
--- libcxx/trunk/benchmarks/stringstream.bench.cpp (added)
+++ libcxx/trunk/benchmarks/stringstream.bench.cpp Wed Jun 14 18:17:45 2017
@@ -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()
Modified: libcxx/trunk/include/__config
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/__config?rev=305427&r1=305426&r2=305427&view=diff
==============================================================================
--- libcxx/trunk/include/__config (original)
+++ libcxx/trunk/include/__config Wed Jun 14 18:17:45 2017
@@ -76,6 +76,9 @@
// its vtable and typeinfo to libc++ rather than having all other libraries
// using that class define their own copies.
#define _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
+
+// Enable optimized version of __do_get_(un)signed which avoids redundant copies.
+#define _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
#elif _LIBCPP_ABI_VERSION == 1
#if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
// Enable compiling copies of now inline methods into the dylib to support
Modified: libcxx/trunk/include/locale
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/locale?rev=305427&r1=305426&r2=305427&view=diff
==============================================================================
--- libcxx/trunk/include/locale (original)
+++ libcxx/trunk/include/locale Wed Jun 14 18:17:45 2017
@@ -372,19 +372,57 @@ template <class _CharT>
struct __num_get
: protected __num_get_base
{
- static string __stage2_int_prep(ios_base& __iob, _CharT* __atoms, _CharT& __thousands_sep);
static string __stage2_float_prep(ios_base& __iob, _CharT* __atoms, _CharT& __decimal_point,
_CharT& __thousands_sep);
- static int __stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
- unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
- unsigned* __g, unsigned*& __g_end, _CharT* __atoms);
+
static int __stage2_float_loop(_CharT __ct, bool& __in_units, char& __exp,
char* __a, char*& __a_end,
_CharT __decimal_point, _CharT __thousands_sep,
const string& __grouping, unsigned* __g,
unsigned*& __g_end, unsigned& __dc, _CharT* __atoms);
+#ifndef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
+ static string __stage2_int_prep(ios_base& __iob, _CharT* __atoms, _CharT& __thousands_sep);
+ static int __stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
+ unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
+ unsigned* __g, unsigned*& __g_end, _CharT* __atoms);
+
+#else
+ static string __stage2_int_prep(ios_base& __iob, _CharT& __thousands_sep)
+ {
+ locale __loc = __iob.getloc();
+ const numpunct<_CharT>& __np = use_facet<numpunct<_CharT> >(__loc);
+ __thousands_sep = __np.thousands_sep();
+ return __np.grouping();
+ }
+
+ const _CharT* __do_widen(ios_base& __iob, _CharT* __atoms) const
+ {
+ return __do_widen_p(__iob, __atoms);
+ }
+
+
+ static int __stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
+ unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
+ unsigned* __g, unsigned*& __g_end, const _CharT* __atoms);
+private:
+ template<typename T>
+ const T* __do_widen_p(ios_base& __iob, T* __atoms) const
+ {
+ locale __loc = __iob.getloc();
+ use_facet<ctype<T> >(__loc).widen(__src, __src + 26, __atoms);
+ return __atoms;
+ }
+
+ const char* __do_widen_p(ios_base& __iob, char* __atoms) const
+ {
+ (void)__iob;
+ (void)__atoms;
+ return __src;
+ }
+#endif
};
+#ifndef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
template <class _CharT>
string
__num_get<_CharT>::__stage2_int_prep(ios_base& __iob, _CharT* __atoms, _CharT& __thousands_sep)
@@ -395,6 +433,7 @@ __num_get<_CharT>::__stage2_int_prep(ios
__thousands_sep = __np.thousands_sep();
return __np.grouping();
}
+#endif
template <class _CharT>
string
@@ -411,9 +450,16 @@ __num_get<_CharT>::__stage2_float_prep(i
template <class _CharT>
int
+#ifndef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
__num_get<_CharT>::__stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
unsigned* __g, unsigned*& __g_end, _CharT* __atoms)
+#else
+__num_get<_CharT>::__stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
+ unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
+ unsigned* __g, unsigned*& __g_end, const _CharT* __atoms)
+
+#endif
{
if (__a_end == __a && (__ct == __atoms[24] || __ct == __atoms[25]))
{
@@ -849,9 +895,16 @@ num_get<_CharT, _InputIterator>::__do_ge
// Stage 1
int __base = this->__get_base(__iob);
// Stage 2
- char_type __atoms[26];
char_type __thousands_sep;
+ const int __atoms_size = 26;
+#ifdef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
+ char_type __atoms1[__atoms_size];
+ const char_type *__atoms = this->__do_widen(__iob, __atoms1);
+ string __grouping = this->__stage2_int_prep(__iob, __thousands_sep);
+#else
+ char_type __atoms[__atoms_size];
string __grouping = this->__stage2_int_prep(__iob, __atoms, __thousands_sep);
+#endif
string __buf;
__buf.resize(__buf.capacity());
char* __a = &__buf[0];
@@ -899,9 +952,16 @@ num_get<_CharT, _InputIterator>::__do_ge
// Stage 1
int __base = this->__get_base(__iob);
// Stage 2
- char_type __atoms[26];
char_type __thousands_sep;
+ const int __atoms_size = 26;
+#ifdef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
+ char_type __atoms1[__atoms_size];
+ const char_type *__atoms = this->__do_widen(__iob, __atoms1);
+ string __grouping = this->__stage2_int_prep(__iob, __thousands_sep);
+#else
+ char_type __atoms[__atoms_size];
string __grouping = this->__stage2_int_prep(__iob, __atoms, __thousands_sep);
+#endif
string __buf;
__buf.resize(__buf.capacity());
char* __a = &__buf[0];
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