Eric Fiselier 58c7fa5ade [libc++] Optimize basic_string::operator=(const basic_string&) for SSO assignments ... This change optimizes the operator=() assignment for short strings by direcly copying the raw data from the source into the current instance. This creates an optimized / inlined mempcy up to over 2X faster for short string assignments. With inlining enabled for operator=, performance is up to 6X faster. Benchmarks 'as is': name old time/op new time/op delta BM_StringAssignStr_Empty_Opaque 6.05ns ± 2% 3.59ns ± 0% -40.67% BM_StringAssignStr_Empty_Transparent 5.15ns ± 0% 3.08ns ± 0% -40.12% BM_StringAssignStr_Small_Opaque 7.71ns ± 0% 3.59ns ± 0% -53.45% BM_StringAssignStr_Small_Transparent 7.66ns ± 0% 3.09ns ± 0% -59.66% BM_StringAssignStr_Large_Opaque 24.1ns ± 0% 24.9ns ± 0% +3.22% BM_StringAssignStr_Large_Transparent 22.2ns ± 0% 22.8ns ± 0% +2.77% BM_StringAssignStr_Huge_Opaque 315ns ± 6% 320ns ± 5% ~ BM_StringAssignStr_Huge_Transparent 318ns ± 5% 321ns ± 4% ~ Benchmarks with partial inlining operator=(): name old time/op new time/op delta BM_StringAssignStr_Empty_Opaque 5.94ns ± 2% 1.95ns ± 0% -67.21% BM_StringAssignStr_Empty_Transparent 5.14ns ± 0% 1.04ns ± 1% -79.73% BM_StringAssignStr_Small_Opaque 7.69ns ± 0% 1.96ns ± 0% -74.48% BM_StringAssignStr_Small_Transparent 7.65ns ± 0% 1.04ns ± 0% -86.40% BM_StringAssignStr_Large_Opaque 24.1ns ± 0% 24.5ns ± 0% +1.61% BM_StringAssignStr_Large_Transparent 22.2ns ± 0% 21.1ns ± 0% -4.70% BM_StringAssignStr_Huge_Opaque 317ns ± 5% 323ns ± 4% ~ BM_StringAssignStr_Huge_Transparent 318ns ± 5% 320ns ± 5% ~ Patch by Martijn Vels (mvels@google.com) Reviewed as https://reviews.llvm.org/D72704		2020-01-15 17:27:10 -05:00
..
benchmarks	[libc++] Add additional benchmark functions to libcxx/benchmarks/string.bench	2020-01-07 16:31:40 -05:00
cmake	[libcxx{,abi}] Don't link libpthread and libdl on Fuchsia	2019-12-06 11:15:15 -08:00
docs	Bump the trunk major version to 11	2020-01-15 13:38:01 +01:00
fuzzing	[libc++] Tolerate NaN returning random distributions for now	2019-12-12 17:11:13 -05:00
include	[libc++] Optimize basic_string::operator=(const basic_string&) for SSO assignments	2020-01-15 17:27:10 -05:00
lib	[libc++] Add missing revision number in ABI changelog	2019-10-03 16:50:05 +00:00
src	[libc++] Explicitly enumerate std::string external instantiations - Attempt 2	2020-01-15 17:12:49 -05:00
test	[libcxx] [test] Add casts to avoid signed/unsigned mismatch warnings on MSVC++	2020-01-14 01:11:10 -08:00
utils	[libcxx] Fix a typo in config.py	2019-12-26 18:51:09 +03:00
www	[libc++] [P0920] [P1661] Update status page.	2019-11-15 00:12:34 +01:00
.arcconfig
.clang-format
.gitignore
appveyor-reqs-install.cmd	Attempt to upgrade compiler used by appveyor builds	2019-04-03 20:40:01 +00:00
appveyor.yml	disable appveyor config for MSVC 2015	2019-04-03 20:36:51 +00:00
CMakeLists.txt	Bump the trunk major version to 11	2020-01-15 13:38:01 +01:00
CREDITS.TXT	[libcxx] Add Sergej Jaskiewicz to CREDITS.txt	2019-11-21 12:06:10 +03:00
LICENSE.TXT	Fix typos throughout the license files that somehow I and my reviewers	2019-01-21 09:52:34 +00:00
NOTES.TXT
TODO.TXT