Red Hat's newlib C library with support for Jehanne
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Wilco Dijkstra 473f1a3a5d Improve performance of strstr
v3: Add support for read ahead using strnlen, giving an additional 25% speedup
on large inputs (both short and long needles).

This patch significantly improves performance of strstr by using Sunday's
Quick-Search algorithm.  Due to its simplicity it has the best average
performance of string matching algorithms on almost all inputs.  It uses a
bad-character shift table to skip past mismatches.

The needle length is limited to 254 - this reduces the shift table memory
4 to 8 times, lowering preprocessing overhead and minimizing cache effects.
The limit also implies its worst-case performance is linear.

Larger needles are processed by the Two-Way algorithm.  The macro AVAILABLE
has been improved to use strnlen to read the input in chunks.  This results
in a 2.5 times speedup for large needles, reducing the performance drop when
the Quick-Search algorithm can't be used.

The code for 1-4 byte needles has been simplified and now uses unsigned
char.  Since the optimized code relies on 8-bit chars, we defer to the
size-optimized implementation if CHAR_BIT > 8.

The performance gain of finding a set of randomly chosen words of size 8 in
256 bytes of English text is 14 times on AArch64. For longer haystacks the
gain is well over 20 times.

The size-optimized strstr has also been rewritten from scratch to improve
performance.  On the same test the performance gain is 69%.

Tested against GLIBC testsuite, randomized tests and the GNULIB strstr test
(https://git.savannah.gnu.org/cgit/gnulib.git/tree/tests/test-strstr.c).

--
2018-10-18 19:51:39 +02:00
config Sync with upstream gcc. 2016-06-23 15:54:55 -04:00
etc Remove spurious empty line in changelog entry. 2016-03-22 10:29:22 +01:00
include Sync with upstream gcc. 2016-06-23 15:54:55 -04:00
libgloss [Aarch64] Syscalls: fix prototypes 2018-10-08 14:39:16 +01:00
newlib Improve performance of strstr 2018-10-18 19:51:39 +02:00
texinfo * texinfo/texinfo.tex: Update to version 2009-03-28.05. 2009-04-21 12:36:46 +00:00
winsup Move common <sys/dirent.h> content to <dirent.h> 2018-10-11 08:29:16 +02:00
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COPYING
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COPYING.NEWLIB Update Arm entry in COPYING.NEWLIB. 2018-09-25 15:10:46 -04:00
COPYING3
COPYING3.LIB
ChangeLog Sync with upstream gcc. 2016-06-23 15:54:55 -04:00
MAINTAINERS MAINTAINERS: clarify policy with config/ (and other top level files) 2012-05-12 03:10:17 +00:00
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Makefile.in Introduce @unless/@endunless and postbootstrap Makefile targets 2018-06-30 00:12:40 -03:00
Makefile.tpl Introduce @unless/@endunless and postbootstrap Makefile targets 2018-06-30 00:12:40 -03:00
README
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config.rpath Remove freebsd1 from libtool.m4 macros and config.rpath. 2011-02-13 21:00:08 +00:00
config.sub Update config.guess and config.sub 2018-07-06 10:46:43 +02:00
configure Introduce @unless/@endunless and postbootstrap Makefile targets 2018-06-30 00:12:40 -03:00
configure.ac Introduce @unless/@endunless and postbootstrap Makefile targets 2018-06-30 00:12:40 -03:00
depcomp Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00
djunpack.bat * djunpack.bat: Use ".." quoting in Sed command, for the sake of 2009-03-27 13:37:09 +00:00
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ltgcc.m4
ltmain.sh PR target/59788 2014-02-05 13:17:47 +00:00
ltoptions.m4 Sync Libtool from GCC. 2010-01-09 21:11:32 +00:00
ltsugar.m4
ltversion.m4 Sync Libtool from GCC. 2010-01-09 21:11:32 +00:00
lt~obsolete.m4 Sync Libtool from GCC. 2010-01-09 21:11:32 +00:00
makefile.vms
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mkdep
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setup.com 2009-09-01 Tristan Gingold <gingold@adacore.com> 2009-09-01 13:38:26 +00:00
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ylwrap Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00

README

		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.