3a3c09c5dd
Use the new __has_feature(cxx_constexpr_string_builtins) for detection of the C-string intrinsics for constexpr support in std::char_traits. Thanks to Richard for the intrisic support.
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llvm-svn: 293154
2017-01-26 06:58:29 +00:00
9087bbee85
disable use of __builtin_memcmp temporarily to get the tests passing again
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llvm-svn: 291742
2017-01-12 05:40:58 +00:00
05d57faa2e
Implement P0426: Constexpr for std::char_traits
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llvm-svn: 291741
2017-01-12 04:37:14 +00:00
e2f2d1edef
[NFC] Rename _LIBCPP_TYPE_VIS_ONLY to _LIBCPP_TEMPLATE_VIS
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The name _LIBCPP_TYPE_VIS_ONLY is no longer accurate because both
_LIBCPP_TYPE_VIS and _LIBCPP_TYPE_VIS_ONLY expand to
__attribute__((__type_visibility__)) with Clang. The only remaining difference
is that _LIBCPP_TYPE_VIS_ONLY can be applied to templates whereas
_LIBCPP_TYPE_VIS cannot (due to dllimport/dllexport not being allowed on
templates).
This patch renames _LIBCPP_TYPE_VIS_ONLY to _LIBCPP_TEMPLATE_VIS.
llvm-svn: 291035
2017-01-04 23:56:00 +00:00
9070500633
improve performance of string::find
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string::find used to call the generic algorithm ::find. The patch special
case string::find such that it ultimately gets converted to calls to memchr
and memcmp.
The patch improves the performance of the string::find routine by about 20x.
Without the patch, the performance on an x86_64-linux 3400 MHz machine is:
Benchmark Time CPU Iterations
-----------------------------------------------------------------
BM_StringFindNoMatch/10 4 ns 4 ns 166421326
BM_StringFindNoMatch/64 37 ns 37 ns 18754392
BM_StringFindNoMatch/512 268 ns 268 ns 2586060
BM_StringFindNoMatch/4k 2143 ns 2144 ns 328342
BM_StringFindNoMatch/32k 16910 ns 16917 ns 40623
BM_StringFindNoMatch/128k 67577 ns 67602 ns 10138
BM_StringFindAllMatch/1 3 ns 3 ns 265163471
BM_StringFindAllMatch/8 6 ns 6 ns 112582467
BM_StringFindAllMatch/64 36 ns 36 ns 19566457
BM_StringFindAllMatch/512 209 ns 209 ns 3318893
BM_StringFindAllMatch/4k 1618 ns 1618 ns 432963
BM_StringFindAllMatch/32k 12909 ns 12914 ns 54317
BM_StringFindAllMatch/128k 48342 ns 48361 ns 13922
BM_StringFindMatch1/1 33777 ns 33790 ns 20698
BM_StringFindMatch1/8 33940 ns 33953 ns 20619
BM_StringFindMatch1/64 34038 ns 34051 ns 20571
BM_StringFindMatch1/512 34217 ns 34230 ns 20480
BM_StringFindMatch1/4k 35510 ns 35524 ns 19752
BM_StringFindMatch1/32k 46438 ns 46456 ns 15030
BM_StringFindMatch2/1 33839 ns 33852 ns 20648
BM_StringFindMatch2/8 33950 ns 33963 ns 20594
BM_StringFindMatch2/64 33846 ns 33859 ns 20668
BM_StringFindMatch2/512 34023 ns 34036 ns 20279
BM_StringFindMatch2/4k 35422 ns 35436 ns 19716
BM_StringFindMatch2/32k 46570 ns 46588 ns 15027
With the patch applied
Benchmark Time CPU Iterations
-----------------------------------------------------------------
BM_StringFindNoMatch/10 5 ns 5 ns 133724346
BM_StringFindNoMatch/64 6 ns 6 ns 119312184
BM_StringFindNoMatch/512 13 ns 13 ns 51539628
BM_StringFindNoMatch/4k 77 ns 77 ns 8935934
BM_StringFindNoMatch/32k 551 ns 551 ns 1222808
BM_StringFindNoMatch/128k 2684 ns 2685 ns 259957
BM_StringFindAllMatch/1 7 ns 7 ns 98017959
BM_StringFindAllMatch/8 7 ns 7 ns 91466911
BM_StringFindAllMatch/64 8 ns 8 ns 85707392
BM_StringFindAllMatch/512 20 ns 20 ns 34490895
BM_StringFindAllMatch/4k 93 ns 93 ns 7360375
BM_StringFindAllMatch/32k 827 ns 828 ns 829944
BM_StringFindAllMatch/128k 3593 ns 3594 ns 195815
BM_StringFindMatch1/1 1332 ns 1332 ns 516354
BM_StringFindMatch1/8 1336 ns 1336 ns 495876
BM_StringFindMatch1/64 1338 ns 1339 ns 516656
BM_StringFindMatch1/512 1357 ns 1357 ns 510717
BM_StringFindMatch1/4k 1485 ns 1486 ns 461228
BM_StringFindMatch1/32k 2235 ns 2236 ns 318253
BM_StringFindMatch2/1 1335 ns 1335 ns 517105
BM_StringFindMatch2/8 1336 ns 1337 ns 518004
BM_StringFindMatch2/64 1344 ns 1345 ns 511751
BM_StringFindMatch2/512 1361 ns 1361 ns 508150
BM_StringFindMatch2/4k 1611 ns 1611 ns 463388
BM_StringFindMatch2/32k 2187 ns 2187 ns 317532
Patch written by Aditya Kumar and Sebastian Pop.
Differential Revision: https://reviews.llvm.org/D27068
llvm-svn: 290761
2016-12-30 18:01:36 +00:00
49e2967f27
[libc++] Fix and document visibility attributes for Clang, GCC and Windows.
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Summary:
This patch fixes a number of problems with the visibility macros across GCC (on Unix) and Windows (DLL import/export semantics). All of the visibility macros are now documented under `DesignDocs/VisibilityMacros.rst`. Now I'll no longer forget the subtleties of each!
This patch adds two new visibility macros:
* `_LIBCPP_ENUM_VIS` for controlling the typeinfo of enum types. Only Clang supports this.
* `_LIBCPP_EXTERN_TEMPLATE_TYPE_VIS` for redefining visibility on explicit instantiation declarations. Clang and Windows require this.
After applying this patch GCC only emits one -Wattribute warning opposed to 30+.
Reviewers: mclow.lists, EricWF
Subscribers: beanz, mgorny, cfe-commits
Differential Revision: https://reviews.llvm.org/D24602
llvm-svn: 281673
2016-09-15 22:27:07 +00:00
aa849bc2f2
Add a bunch of noexcepts to char_traits and string_view.
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llvm-svn: 276955
2016-07-28 04:52:02 +00:00
053d81ceeb
Implement std::string_view as described in http://wg21.link/P0254R1 . Reviewed as https://reviews.llvm.org/D21459
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llvm-svn: 276238
2016-07-21 05:31:24 +00:00
Marshall Clow