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Aldy Hernandez d8edfadfc7 Disallow loop rotation and loop header crossing in jump threaders.
There is a lot of fall-out from this patch, as there were many threading
tests that assumed the restrictions introduced by this patch were valid.
Some tests have merely shifted the threading to after loop
optimizations, but others ended up with no threading opportunities at
all.  Surprisingly some tests ended up with more total threads.  It was
a crapshoot all around.

On a postive note, there are 6 tests that no longer XFAIL, and one
guality test which now passes.

I felt a bit queasy about such a fundamental change wrt threading, so I
ran it through my callgrind test harness (.ii files from a bootstrap).
There was no change in overall compilation, DOM, or the VRP threaders.

However, there was a slight increase of 1.63% in the backward threader.
I'm pretty sure we could reduce this if we incorporated the restrictions
into their profitability code.  This way we could stop the search when
we ran into one of these restrictions.  Not sure it's worth it at this
point.

Tested on x86-64 Linux.

Co-authored-by: Richard Biener <rguenther@suse.de>

gcc/ChangeLog:

	* tree-ssa-threadupdate.c (cancel_thread): Dump threading reason
	on the same line as the threading cancellation.
	(jt_path_registry::cancel_invalid_paths): Avoid rotating loops.
	Avoid threading through loop headers where the path remains in the
	loop.

libgomp/ChangeLog:

	* testsuite/libgomp.graphite/force-parallel-5.c: Remove xfail.

gcc/testsuite/ChangeLog:

	* gcc.dg/Warray-bounds-87.c: Remove xfail.
	* gcc.dg/analyzer/pr94851-2.c: Remove xfail.
	* gcc.dg/graphite/pr69728.c: Remove xfail.
	* gcc.dg/graphite/scop-dsyr2k.c: Remove xfail.
	* gcc.dg/graphite/scop-dsyrk.c: Remove xfail.
	* gcc.dg/shrink-wrap-loop.c: Remove xfail.
	* gcc.dg/loop-8.c: Adjust for new threading restrictions.
	* gcc.dg/tree-ssa/ifc-20040816-1.c: Same.
	* gcc.dg/tree-ssa/pr21559.c: Same.
	* gcc.dg/tree-ssa/pr59597.c: Same.
	* gcc.dg/tree-ssa/pr71437.c: Same.
	* gcc.dg/tree-ssa/pr77445-2.c: Same.
	* gcc.dg/tree-ssa/ssa-dom-thread-4.c: Same.
	* gcc.dg/tree-ssa/ssa-dom-thread-7.c: Same.
	* gcc.dg/vect/bb-slp-16.c: Same.
	* gcc.dg/tree-ssa/ssa-dom-thread-6.c: Remove.
	* gcc.dg/tree-ssa/ssa-dom-thread-18.c: Remove.
	* gcc.dg/tree-ssa/ssa-dom-thread-2a.c: Remove.
	* gcc.dg/tree-ssa/ssa-thread-invalid.c: New test.
2021-10-20 07:07:35 +02:00
c++tools Daily bump. 2021-09-15 00:16:29 +00:00
config Daily bump. 2021-09-20 00:16:21 +00:00
contrib Daily bump. 2021-10-19 00:16:23 +00:00
fixincludes Daily bump. 2021-08-31 00:16:50 +00:00
gcc Disallow loop rotation and loop header crossing in jump threaders. 2021-10-20 07:07:35 +02:00
gnattools Daily bump. 2021-05-08 00:16:27 +00:00
gotools Daily bump. 2021-09-22 00:16:28 +00:00
include Daily bump. 2021-09-28 00:16:21 +00:00
INSTALL
intl Daily bump. 2021-06-15 00:16:37 +00:00
libada Update copyright years. 2021-01-04 10:26:59 +01:00
libatomic Daily bump. 2021-07-22 00:16:46 +00:00
libbacktrace Daily bump. 2021-08-14 00:16:29 +00:00
libcc1 Daily bump. 2021-08-18 00:16:48 +00:00
libcody Daily bump. 2021-04-07 00:16:39 +00:00
libcpp Daily bump. 2021-10-19 00:16:23 +00:00
libdecnumber Daily bump. 2021-05-04 00:16:53 +00:00
libffi Daily bump. 2021-08-31 00:16:50 +00:00
libgcc Daily bump. 2021-10-15 00:17:02 +00:00
libgfortran Daily bump. 2021-10-19 00:16:23 +00:00
libgo runtime: set runtime.GOROOT value at build time 2021-09-21 14:31:10 -07:00
libgomp Disallow loop rotation and loop header crossing in jump threaders. 2021-10-20 07:07:35 +02:00
libiberty Daily bump. 2021-10-18 00:16:27 +00:00
libitm Daily bump. 2021-06-18 00:16:58 +00:00
libobjc Daily bump. 2021-01-06 00:16:55 +00:00
liboffloadmic Daily bump. 2021-10-20 00:16:43 +00:00
libphobos Daily bump. 2021-10-01 00:16:27 +00:00
libquadmath Daily bump. 2021-06-09 00:16:30 +00:00
libsanitizer Daily bump. 2021-10-09 00:16:26 +00:00
libssp Daily bump. 2021-01-06 00:16:55 +00:00
libstdc++-v3 Daily bump. 2021-10-20 00:16:43 +00:00
libvtv Daily bump. 2021-01-06 00:16:55 +00:00
lto-plugin Daily bump. 2021-09-14 00:16:23 +00:00
maintainer-scripts Daily bump. 2021-05-15 00:16:27 +00:00
zlib Daily bump. 2021-01-06 00:16:55 +00:00
.dir-locals.el dir-locals: Use https for bug references 2021-07-20 11:40:34 +01:00
.gitattributes
.gitignore Add cscope.out to git ignore. 2021-06-24 16:51:40 +05:30
ABOUT-NLS
ar-lib
ChangeLog Daily bump. 2021-10-20 00:16:43 +00:00
ChangeLog.jit
ChangeLog.tree-ssa
compile
config-ml.in
config.guess config.sub, config.guess : Import upstream 2021-01-25. 2021-02-23 17:21:10 +08:00
config.rpath
config.sub config.sub, config.guess : Import upstream 2021-01-25. 2021-02-23 17:21:10 +08:00
configure top-level configure: setup target_configdirs based on repository 2021-09-28 09:43:36 +01:00
configure.ac top-level configure: setup target_configdirs based on repository 2021-09-28 09:43:36 +01:00
COPYING
COPYING.LIB
COPYING.RUNTIME
COPYING3
COPYING3.LIB
depcomp
install-sh
libtool-ldflags
libtool.m4 Update GNU/Hurd configure support 2021-01-05 16:04:14 -07:00
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
lt~obsolete.m4
MAINTAINERS MAINTAINERS: Add myself for write after approval 2021-10-19 13:38:04 +02:00
Makefile.def Mark certain subdirectories as missing TAGS targets. 2021-10-12 17:00:43 -04:00
Makefile.in Mark certain subdirectories as missing TAGS targets. 2021-10-12 17:00:43 -04:00
Makefile.tpl configure: Allow host fragments to react to --enable-host-shared. 2021-08-18 19:46:32 +01:00
missing
mkdep
mkinstalldirs
move-if-change
multilib.am
README
symlink-tree
test-driver
ylwrap

This directory contains the GNU Compiler Collection (GCC).

The GNU Compiler Collection is free software.  See the files whose
names start with COPYING for copying permission.  The manuals, and
some of the runtime libraries, are under different terms; see the
individual source files for details.

The directory INSTALL contains copies of the installation information
as HTML and plain text.  The source of this information is
gcc/doc/install.texi.  The installation information includes details
of what is included in the GCC sources and what files GCC installs.

See the file gcc/doc/gcc.texi (together with other files that it
includes) for usage and porting information.  An online readable
version of the manual is in the files gcc/doc/gcc.info*.

See http://gcc.gnu.org/bugs/ for how to report bugs usefully.

Copyright years on GCC source files may be listed using range
notation, e.g., 1987-2012, indicating that every year in the range,
inclusive, is a copyrightable year that could otherwise be listed
individually.