After gcc commit 4a960d548b7d7d942f316c5295f6d849b74214f5
Author: Aldy Hernandez <aldyh(a)redhat.com>
Avoid invalid loop transformations in jump threading registry.
the following benchmarks grew in size by more than 1%:
- 450.soplex grew in size by 2% from 207260 to 211436 bytes
Below reproducer instructions can be used to re-build both "first_bad" and "last_good" cross-toolchains used in this bisection. Naturally, the scripts will fail when triggerring benchmarking jobs if you don't have access to Linaro TCWG CI.
For your convenience, we have uploaded tarballs with pre-processed source and assembly files at:
- First_bad save-temps: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_apm-gnu-master-aa…
- Last_good save-temps: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_apm-gnu-master-aa…
- Baseline save-temps: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_apm-gnu-master-aa…
Configuration:
- Benchmark: SPEC CPU2006
- Toolchain: GCC + Glibc + GNU Linker
- Version: all components were built from their tip of trunk
- Target: aarch64-linux-gnu
- Compiler flags: -Os -flto
- Hardware: APM Mustang 8x X-Gene1
This benchmarking CI is work-in-progress, and we welcome feedback and suggestions at linaro-toolchain(a)lists.linaro.org . In our improvement plans is to add support for SPEC CPU2017 benchmarks and provide "perf report/annotate" data behind these reports.
THIS IS THE END OF INTERESTING STUFF. BELOW ARE LINKS TO BUILDS, REPRODUCTION INSTRUCTIONS, AND THE RAW COMMIT.
This commit has regressed these CI configurations:
- tcwg_bmk_gnu_apm/gnu-master-aarch64-spec2k6-Os_LTO
First_bad build: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_apm-gnu-master-aa…
Last_good build: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_apm-gnu-master-aa…
Baseline build: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_apm-gnu-master-aa…
Even more details: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_apm-gnu-master-aa…
Reproduce builds:
<cut>
mkdir investigate-gcc-4a960d548b7d7d942f316c5295f6d849b74214f5
cd investigate-gcc-4a960d548b7d7d942f316c5295f6d849b74214f5
# Fetch scripts
git clone https://git.linaro.org/toolchain/jenkins-scripts
# Fetch manifests and test.sh script
mkdir -p artifacts/manifests
curl -o artifacts/manifests/build-baseline.sh https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_apm-gnu-master-aa… --fail
curl -o artifacts/manifests/build-parameters.sh https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_apm-gnu-master-aa… --fail
curl -o artifacts/test.sh https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_apm-gnu-master-aa… --fail
chmod +x artifacts/test.sh
# Reproduce the baseline build (build all pre-requisites)
./jenkins-scripts/tcwg_bmk-build.sh @@ artifacts/manifests/build-baseline.sh
# Save baseline build state (which is then restored in artifacts/test.sh)
mkdir -p ./bisect
rsync -a --del --delete-excluded --exclude /bisect/ --exclude /artifacts/ --exclude /gcc/ ./ ./bisect/baseline/
cd gcc
# Reproduce first_bad build
git checkout --detach 4a960d548b7d7d942f316c5295f6d849b74214f5
../artifacts/test.sh
# Reproduce last_good build
git checkout --detach 29c92857039d0a105281be61c10c9e851aaeea4a
../artifacts/test.sh
cd ..
</cut>
Full commit (up to 1000 lines):
<cut>
commit 4a960d548b7d7d942f316c5295f6d849b74214f5
Author: Aldy Hernandez <aldyh(a)redhat.com>
Date: Thu Sep 23 10:59:24 2021 +0200
Avoid invalid loop transformations in jump threading registry.
My upcoming improvements to the forward jump threader make it thread
more aggressively. In investigating some "regressions", I noticed
that it has always allowed threading through empty latches and across
loop boundaries. As we have discussed recently, this should be avoided
until after loop optimizations have run their course.
Note that this wasn't much of a problem before because DOM/VRP
couldn't find these opportunities, but with a smarter solver, we trip
over them more easily.
Because the forward threader doesn't have an independent localized cost
model like the new threader (profitable_path_p), it is difficult to
catch these things at discovery. However, we can catch them at
registration time, with the added benefit that all the threaders
(forward and backward) can share the handcuffs.
This patch is an adaptation of what we do in the backward threader, but
it is not meant to catch everything we do there, as some of the
restrictions there are due to limitations of the different block
copiers (for example, the generic copier does not re-use existing
threading paths).
We could ideally remove the now redundant bits in profitable_path_p, but
I would prefer not to for two reasons. First, the backward threader uses
profitable_path_p as it discovers paths to avoid discovering paths in
unprofitable directions. Second, I would like to merge all the forward
cost restrictions into the profitability class in the backward threader,
not the other way around. Alas, that reshuffling will have to wait for
the next release.
As usual, there are quite a few tests that needed adjustments. It seems
we were quite happily threading improper scenarios. With most of them,
as can be seen in pr77445-2.c, we're merely shifting the threading to
after loop optimizations.
Tested on x86-64 Linux.
gcc/ChangeLog:
* tree-ssa-threadupdate.c (jt_path_registry::cancel_invalid_paths):
New.
(jt_path_registry::register_jump_thread): Call
cancel_invalid_paths.
* tree-ssa-threadupdate.h (class jt_path_registry): Add
cancel_invalid_paths.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/20030714-2.c: Adjust.
* gcc.dg/tree-ssa/pr66752-3.c: Adjust.
* gcc.dg/tree-ssa/pr77445-2.c: Adjust.
* gcc.dg/tree-ssa/ssa-dom-thread-18.c: Adjust.
* gcc.dg/tree-ssa/ssa-dom-thread-7.c: Adjust.
* gcc.dg/vect/bb-slp-16.c: Adjust.
---
gcc/testsuite/gcc.dg/tree-ssa/20030714-2.c | 7 ++-
gcc/testsuite/gcc.dg/tree-ssa/pr66752-3.c | 19 ++++---
gcc/testsuite/gcc.dg/tree-ssa/pr77445-2.c | 4 +-
gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-18.c | 4 +-
gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-7.c | 4 +-
gcc/testsuite/gcc.dg/vect/bb-slp-16.c | 7 ---
gcc/tree-ssa-threadupdate.c | 67 ++++++++++++++++++-----
gcc/tree-ssa-threadupdate.h | 1 +
8 files changed, 78 insertions(+), 35 deletions(-)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/20030714-2.c b/gcc/testsuite/gcc.dg/tree-ssa/20030714-2.c
index eb663f2ff5b..9585ff11307 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/20030714-2.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/20030714-2.c
@@ -32,7 +32,8 @@ get_alias_set (t)
}
}
-/* There should be exactly three IF conditionals if we thread jumps
- properly. */
-/* { dg-final { scan-tree-dump-times "if " 3 "dom2"} } */
+/* There should be exactly 4 IF conditionals if we thread jumps
+ properly. There used to be 3, but one thread was crossing
+ loops. */
+/* { dg-final { scan-tree-dump-times "if " 4 "dom2"} } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr66752-3.c b/gcc/testsuite/gcc.dg/tree-ssa/pr66752-3.c
index e1464e21170..922a331b217 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr66752-3.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr66752-3.c
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-thread1-details -fdump-tree-dce2" } */
+/* { dg-options "-O2 -fdump-tree-thread1-details -fdump-tree-thread3" } */
extern int status, pt;
extern int count;
@@ -32,10 +32,15 @@ foo (int N, int c, int b, int *a)
pt--;
}
-/* There are 4 jump threading opportunities, all of which will be
- realized, which will eliminate testing of FLAG, completely. */
-/* { dg-final { scan-tree-dump-times "Registering jump" 4 "thread1"} } */
+/* There are 2 jump threading opportunities (which don't cross loops),
+ all of which will be realized, which will eliminate testing of
+ FLAG, completely. */
+/* { dg-final { scan-tree-dump-times "Registering jump" 2 "thread1"} } */
-/* There should be no assignments or references to FLAG, verify they're
- eliminated as early as possible. */
-/* { dg-final { scan-tree-dump-not "if .flag" "dce2"} } */
+/* We used to remove references to FLAG by DCE2, but this was
+ depending on early threaders threading through loop boundaries
+ (which we shouldn't do). However, the late threading passes, which
+ run after loop optimizations , can successfully eliminate the
+ references to FLAG. Verify that ther are no references by the late
+ threading passes. */
+/* { dg-final { scan-tree-dump-not "if .flag" "thread3"} } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr77445-2.c b/gcc/testsuite/gcc.dg/tree-ssa/pr77445-2.c
index f9fc212f49e..01a0f1f197d 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr77445-2.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr77445-2.c
@@ -123,8 +123,8 @@ enum STATES FMS( u8 **in , u32 *transitions) {
aarch64 has the highest CASE_VALUES_THRESHOLD in GCC. It's high enough
to change decisions in switch expansion which in turn can expose new
jump threading opportunities. Skip the later tests on aarch64. */
-/* { dg-final { scan-tree-dump "Jumps threaded: 1\[1-9\]" "thread1" } } */
-/* { dg-final { scan-tree-dump-times "Invalid sum" 4 "thread1" } } */
+/* { dg-final { scan-tree-dump "Jumps threaded: 9" "thread1" } } */
+/* { dg-final { scan-tree-dump-times "Invalid sum" 1 "thread1" } } */
/* { dg-final { scan-tree-dump-not "optimizing for size" "thread1" } } */
/* { dg-final { scan-tree-dump-not "optimizing for size" "thread2" } } */
/* { dg-final { scan-tree-dump-not "optimizing for size" "thread3" { target { ! aarch64*-*-* } } } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-18.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-18.c
index 60d4f76f076..2d78d045516 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-18.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-18.c
@@ -21,5 +21,7 @@
condition.
All the cases are picked up by VRP1 as jump threads. */
-/* { dg-final { scan-tree-dump-times "Registering jump" 6 "thread1" } } */
+
+/* There used to be 6 jump threads found by thread1, but they all
+ depended on threading through distinct loops in ethread. */
/* { dg-final { scan-tree-dump-times "Threaded" 2 "vrp1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-7.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-7.c
index e3d4b311c03..16abcde5053 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-7.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-7.c
@@ -1,8 +1,8 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-thread1-stats -fdump-tree-thread2-stats -fdump-tree-dom2-stats -fdump-tree-thread3-stats -fdump-tree-dom3-stats -fdump-tree-vrp2-stats -fno-guess-branch-probability" } */
-/* { dg-final { scan-tree-dump "Jumps threaded: 18" "thread1" } } */
-/* { dg-final { scan-tree-dump "Jumps threaded: 8" "thread3" { target { ! aarch64*-*-* } } } } */
+/* { dg-final { scan-tree-dump "Jumps threaded: 12" "thread1" } } */
+/* { dg-final { scan-tree-dump "Jumps threaded: 5" "thread3" { target { ! aarch64*-*-* } } } } */
/* { dg-final { scan-tree-dump-not "Jumps threaded" "dom2" } } */
/* aarch64 has the highest CASE_VALUES_THRESHOLD in GCC. It's high enough
diff --git a/gcc/testsuite/gcc.dg/vect/bb-slp-16.c b/gcc/testsuite/gcc.dg/vect/bb-slp-16.c
index 664e93e9b60..e68a9b62535 100644
--- a/gcc/testsuite/gcc.dg/vect/bb-slp-16.c
+++ b/gcc/testsuite/gcc.dg/vect/bb-slp-16.c
@@ -1,8 +1,5 @@
/* { dg-require-effective-target vect_int } */
-/* See note below as to why we disable threading. */
-/* { dg-additional-options "-fdisable-tree-thread1" } */
-
#include <stdarg.h>
#include "tree-vect.h"
@@ -30,10 +27,6 @@ main1 (int dummy)
*pout++ = *pin++ + a;
*pout++ = *pin++ + a;
*pout++ = *pin++ + a;
- /* In some architectures like ppc64, jump threading may thread
- the iteration where i==0 such that we no longer optimize the
- BB. Another alternative to disable jump threading would be
- to wrap the read from `i' into a function returning i. */
if (arr[i] = i)
a = i;
else
diff --git a/gcc/tree-ssa-threadupdate.c b/gcc/tree-ssa-threadupdate.c
index baac11280fa..2b9b8f81274 100644
--- a/gcc/tree-ssa-threadupdate.c
+++ b/gcc/tree-ssa-threadupdate.c
@@ -2757,6 +2757,58 @@ fwd_jt_path_registry::update_cfg (bool may_peel_loop_headers)
return retval;
}
+bool
+jt_path_registry::cancel_invalid_paths (vec<jump_thread_edge *> &path)
+{
+ gcc_checking_assert (!path.is_empty ());
+ edge taken_edge = path[path.length () - 1]->e;
+ loop_p loop = taken_edge->src->loop_father;
+ bool seen_latch = false;
+ bool path_crosses_loops = false;
+
+ for (unsigned int i = 0; i < path.length (); i++)
+ {
+ edge e = path[i]->e;
+
+ if (e == NULL)
+ {
+ // NULL outgoing edges on a path can happen for jumping to a
+ // constant address.
+ cancel_thread (&path, "Found NULL edge in jump threading path");
+ return true;
+ }
+
+ if (loop->latch == e->src || loop->latch == e->dest)
+ seen_latch = true;
+
+ // The first entry represents the block with an outgoing edge
+ // that we will redirect to the jump threading path. Thus we
+ // don't care about that block's loop father.
+ if ((i > 0 && e->src->loop_father != loop)
+ || e->dest->loop_father != loop)
+ path_crosses_loops = true;
+
+ if (flag_checking && !m_backedge_threads)
+ gcc_assert ((path[i]->e->flags & EDGE_DFS_BACK) == 0);
+ }
+
+ if (cfun->curr_properties & PROP_loop_opts_done)
+ return false;
+
+ if (seen_latch && empty_block_p (loop->latch))
+ {
+ cancel_thread (&path, "Threading through latch before loop opts "
+ "would create non-empty latch");
+ return true;
+ }
+ if (path_crosses_loops)
+ {
+ cancel_thread (&path, "Path crosses loops");
+ return true;
+ }
+ return false;
+}
+
/* Register a jump threading opportunity. We queue up all the jump
threading opportunities discovered by a pass and update the CFG
and SSA form all at once.
@@ -2776,19 +2828,8 @@ jt_path_registry::register_jump_thread (vec<jump_thread_edge *> *path)
return false;
}
- /* First make sure there are no NULL outgoing edges on the jump threading
- path. That can happen for jumping to a constant address. */
- for (unsigned int i = 0; i < path->length (); i++)
- {
- if ((*path)[i]->e == NULL)
- {
- cancel_thread (path, "Found NULL edge in jump threading path");
- return false;
- }
-
- if (flag_checking && !m_backedge_threads)
- gcc_assert (((*path)[i]->e->flags & EDGE_DFS_BACK) == 0);
- }
+ if (cancel_invalid_paths (*path))
+ return false;
if (dump_file && (dump_flags & TDF_DETAILS))
dump_jump_thread_path (dump_file, *path, true);
diff --git a/gcc/tree-ssa-threadupdate.h b/gcc/tree-ssa-threadupdate.h
index 8b48a671212..d68795c9f27 100644
--- a/gcc/tree-ssa-threadupdate.h
+++ b/gcc/tree-ssa-threadupdate.h
@@ -75,6 +75,7 @@ protected:
unsigned long m_num_threaded_edges;
private:
virtual bool update_cfg (bool peel_loop_headers) = 0;
+ bool cancel_invalid_paths (vec<jump_thread_edge *> &path);
jump_thread_path_allocator m_allocator;
// True if threading through back edges is allowed. This is only
// allowed in the generic copier in the backward threader.
</cut>
Progress
* UM-2 [QEMU upstream maintainership]
+ Still looking at the mess that is non-unique bus names. Worked
through exactly which devices and machine types are affected for
the i2c bus.
+ Sent a patchset which tries to make the "create a bus" function
names a bit more regular across different bus types.
* QEMU-406 [QEMU support for MVE (M-profile Vector Extension; Helium)]
+ Luis figured out why GDB was crashing when fed the MVE XML by
QEMU's gdbstub; this was a combination of QEMU giving GDB some
non-standard extra registers in its "vfp" XML feature and GDB
not being robust enough against those unexpected extras. Sent
out a patchset which cleans up QEMU's XML in this area and also
implements the extra XML for MVE. (This will only go into QEMU
once the GDB patches have landed and the XML format is nailed down.)
-- PMM
After gcc commit f92901a508305f291fcf2acae0825379477724de
Author: Richard Biener <rguenther(a)suse.de>
tree-optimization/65206 - dependence analysis on mixed pointer/array
the following benchmarks slowed down by more than 2%:
- 482.sphinx3 slowed down by 4% from 20816 to 21661 perf samples
Below reproducer instructions can be used to re-build both "first_bad" and "last_good" cross-toolchains used in this bisection. Naturally, the scripts will fail when triggerring benchmarking jobs if you don't have access to Linaro TCWG CI.
For your convenience, we have uploaded tarballs with pre-processed source and assembly files at:
- First_bad save-temps: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_tx1-gnu-master-aa…
- Last_good save-temps: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_tx1-gnu-master-aa…
- Baseline save-temps: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_tx1-gnu-master-aa…
Configuration:
- Benchmark: SPEC CPU2006
- Toolchain: GCC + Glibc + GNU Linker
- Version: all components were built from their tip of trunk
- Target: aarch64-linux-gnu
- Compiler flags: -O3
- Hardware: NVidia TX1 4x Cortex-A57
This benchmarking CI is work-in-progress, and we welcome feedback and suggestions at linaro-toolchain(a)lists.linaro.org . In our improvement plans is to add support for SPEC CPU2017 benchmarks and provide "perf report/annotate" data behind these reports.
THIS IS THE END OF INTERESTING STUFF. BELOW ARE LINKS TO BUILDS, REPRODUCTION INSTRUCTIONS, AND THE RAW COMMIT.
This commit has regressed these CI configurations:
- tcwg_bmk_gnu_tx1/gnu-master-aarch64-spec2k6-O3
First_bad build: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_tx1-gnu-master-aa…
Last_good build: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_tx1-gnu-master-aa…
Baseline build: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_tx1-gnu-master-aa…
Even more details: https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_tx1-gnu-master-aa…
Reproduce builds:
<cut>
mkdir investigate-gcc-f92901a508305f291fcf2acae0825379477724de
cd investigate-gcc-f92901a508305f291fcf2acae0825379477724de
# Fetch scripts
git clone https://git.linaro.org/toolchain/jenkins-scripts
# Fetch manifests and test.sh script
mkdir -p artifacts/manifests
curl -o artifacts/manifests/build-baseline.sh https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_tx1-gnu-master-aa… --fail
curl -o artifacts/manifests/build-parameters.sh https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_tx1-gnu-master-aa… --fail
curl -o artifacts/test.sh https://ci.linaro.org/job/tcwg_bmk_ci_gnu-bisect-tcwg_bmk_tx1-gnu-master-aa… --fail
chmod +x artifacts/test.sh
# Reproduce the baseline build (build all pre-requisites)
./jenkins-scripts/tcwg_bmk-build.sh @@ artifacts/manifests/build-baseline.sh
# Save baseline build state (which is then restored in artifacts/test.sh)
mkdir -p ./bisect
rsync -a --del --delete-excluded --exclude /bisect/ --exclude /artifacts/ --exclude /gcc/ ./ ./bisect/baseline/
cd gcc
# Reproduce first_bad build
git checkout --detach f92901a508305f291fcf2acae0825379477724de
../artifacts/test.sh
# Reproduce last_good build
git checkout --detach abdf63d782cba82b5ecf264248518cbb065650ed
../artifacts/test.sh
cd ..
</cut>
Full commit (up to 1000 lines):
<cut>
commit f92901a508305f291fcf2acae0825379477724de
Author: Richard Biener <rguenther(a)suse.de>
Date: Wed Sep 8 14:42:31 2021 +0200
tree-optimization/65206 - dependence analysis on mixed pointer/array
This adds the capability to analyze the dependence of mixed
pointer/array accesses. The example is from where using a masked
load/store creates the pointer-based access when an otherwise
unconditional access is array based. Other examples would include
accesses to an array mixed with accesses from inlined helpers
that work on pointers.
The idea is quite simple and old - analyze the data-ref indices
as if the reference was pointer-based. The following change does
this by changing dr_analyze_indices to work on the indices
sub-structure and storing an alternate indices substructure in
each data reference. That alternate set of indices is analyzed
lazily by initialize_data_dependence_relation when it fails to
match-up the main set of indices of two data references.
initialize_data_dependence_relation is refactored into a head
and a tail worker and changed to work on one of the indices
structures and thus away from using DR_* access macros which
continue to reference the main indices substructure.
There are quite some vectorization and loop distribution opportunities
unleashed in SPEC CPU 2017, notably 520.omnetpp_r, 548.exchange2_r,
510.parest_r, 511.povray_r, 521.wrf_r, 526.blender_r, 527.cam4_r and
544.nab_r see amendments in what they report with -fopt-info-loop while
the rest of the specrate set sees no changes there. Measuring runtime
for the set where changes were reported reveals nothing off-noise
besides 511.povray_r which seems to regress slightly for me
(on a Zen2 machine with -Ofast -march=native).
2021-09-08 Richard Biener <rguenther(a)suse.de>
PR tree-optimization/65206
* tree-data-ref.h (struct data_reference): Add alt_indices,
order it last.
* tree-data-ref.c (free_data_ref): Release alt_indices.
(dr_analyze_indices): Work on struct indices and get DR_REF as tree.
(create_data_ref): Adjust.
(initialize_data_dependence_relation): Split into head
and tail. When the base objects fail to match up try
again with pointer-based analysis of indices.
* tree-vectorizer.c (vec_info_shared::check_datarefs): Do
not compare the lazily computed alternate set of indices.
* gcc.dg/torture/20210916.c: New testcase.
* gcc.dg/vect/pr65206.c: Likewise.
---
gcc/testsuite/gcc.dg/torture/20210916.c | 20 ++++
gcc/testsuite/gcc.dg/vect/pr65206.c | 22 ++++
gcc/tree-data-ref.c | 174 +++++++++++++++++++++-----------
gcc/tree-data-ref.h | 9 +-
gcc/tree-vectorizer.c | 3 +-
5 files changed, 168 insertions(+), 60 deletions(-)
diff --git a/gcc/testsuite/gcc.dg/torture/20210916.c b/gcc/testsuite/gcc.dg/torture/20210916.c
new file mode 100644
index 00000000000..0ea6d45e463
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/20210916.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+
+typedef union tree_node *tree;
+struct tree_base {
+ unsigned : 1;
+ unsigned lang_flag_2 : 1;
+};
+struct tree_type {
+ tree main_variant;
+};
+union tree_node {
+ struct tree_base base;
+ struct tree_type type;
+};
+tree finish_struct_t, finish_struct_x;
+void finish_struct()
+{
+ for (; finish_struct_t->type.main_variant;)
+ finish_struct_x->base.lang_flag_2 = 0;
+}
diff --git a/gcc/testsuite/gcc.dg/vect/pr65206.c b/gcc/testsuite/gcc.dg/vect/pr65206.c
new file mode 100644
index 00000000000..3b6262622c0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr65206.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target vect_double } */
+/* { dg-additional-options "-fno-trapping-math -fno-allow-store-data-races" } */
+/* { dg-additional-options "-mavx" { target avx } } */
+
+#define N 1024
+
+double a[N], b[N];
+
+void foo ()
+{
+ for (int i = 0; i < N; ++i)
+ if (b[i] < 3.)
+ a[i] += b[i];
+}
+
+/* We get a .MASK_STORE because while the load of a[i] does not trap
+ the store would introduce store data races. Make sure we still
+ can handle the data dependence with zero distance. */
+
+/* { dg-final { scan-tree-dump-not "versioning for alias required" "vect" { target { vect_masked_store || avx } } } } */
+/* { dg-final { scan-tree-dump "vectorized 1 loops in function" "vect" { target { vect_masked_store || avx } } } } */
diff --git a/gcc/tree-data-ref.c b/gcc/tree-data-ref.c
index e061baa7c20..18307a554fc 100644
--- a/gcc/tree-data-ref.c
+++ b/gcc/tree-data-ref.c
@@ -99,6 +99,7 @@ along with GCC; see the file COPYING3. If not see
#include "internal-fn.h"
#include "vr-values.h"
#include "range-op.h"
+#include "tree-ssa-loop-ivopts.h"
static struct datadep_stats
{
@@ -1300,22 +1301,18 @@ base_supports_access_fn_components_p (tree base)
DR, analyzed in LOOP and instantiated before NEST. */
static void
-dr_analyze_indices (struct data_reference *dr, edge nest, loop_p loop)
+dr_analyze_indices (struct indices *dri, tree ref, edge nest, loop_p loop)
{
- vec<tree> access_fns = vNULL;
- tree ref, op;
- tree base, off, access_fn;
-
/* If analyzing a basic-block there are no indices to analyze
and thus no access functions. */
if (!nest)
{
- DR_BASE_OBJECT (dr) = DR_REF (dr);
- DR_ACCESS_FNS (dr).create (0);
+ dri->base_object = ref;
+ dri->access_fns.create (0);
return;
}
- ref = DR_REF (dr);
+ vec<tree> access_fns = vNULL;
/* REALPART_EXPR and IMAGPART_EXPR can be handled like accesses
into a two element array with a constant index. The base is
@@ -1338,8 +1335,8 @@ dr_analyze_indices (struct data_reference *dr, edge nest, loop_p loop)
{
if (TREE_CODE (ref) == ARRAY_REF)
{
- op = TREE_OPERAND (ref, 1);
- access_fn = analyze_scalar_evolution (loop, op);
+ tree op = TREE_OPERAND (ref, 1);
+ tree access_fn = analyze_scalar_evolution (loop, op);
access_fn = instantiate_scev (nest, loop, access_fn);
access_fns.safe_push (access_fn);
}
@@ -1370,16 +1367,16 @@ dr_analyze_indices (struct data_reference *dr, edge nest, loop_p loop)
analyzed nest, add it as an additional independent access-function. */
if (TREE_CODE (ref) == MEM_REF)
{
- op = TREE_OPERAND (ref, 0);
- access_fn = analyze_scalar_evolution (loop, op);
+ tree op = TREE_OPERAND (ref, 0);
+ tree access_fn = analyze_scalar_evolution (loop, op);
access_fn = instantiate_scev (nest, loop, access_fn);
if (TREE_CODE (access_fn) == POLYNOMIAL_CHREC)
{
- tree orig_type;
tree memoff = TREE_OPERAND (ref, 1);
- base = initial_condition (access_fn);
- orig_type = TREE_TYPE (base);
+ tree base = initial_condition (access_fn);
+ tree orig_type = TREE_TYPE (base);
STRIP_USELESS_TYPE_CONVERSION (base);
+ tree off;
split_constant_offset (base, &base, &off);
STRIP_USELESS_TYPE_CONVERSION (base);
/* Fold the MEM_REF offset into the evolutions initial
@@ -1424,7 +1421,7 @@ dr_analyze_indices (struct data_reference *dr, edge nest, loop_p loop)
base, memoff);
MR_DEPENDENCE_CLIQUE (ref) = MR_DEPENDENCE_CLIQUE (old);
MR_DEPENDENCE_BASE (ref) = MR_DEPENDENCE_BASE (old);
- DR_UNCONSTRAINED_BASE (dr) = true;
+ dri->unconstrained_base = true;
access_fns.safe_push (access_fn);
}
}
@@ -1436,8 +1433,8 @@ dr_analyze_indices (struct data_reference *dr, edge nest, loop_p loop)
build_int_cst (reference_alias_ptr_type (ref), 0));
}
- DR_BASE_OBJECT (dr) = ref;
- DR_ACCESS_FNS (dr) = access_fns;
+ dri->base_object = ref;
+ dri->access_fns = access_fns;
}
/* Extracts the alias analysis information from the memory reference DR. */
@@ -1463,6 +1460,8 @@ void
free_data_ref (data_reference_p dr)
{
DR_ACCESS_FNS (dr).release ();
+ if (dr->alt_indices.base_object)
+ dr->alt_indices.access_fns.release ();
free (dr);
}
@@ -1497,7 +1496,7 @@ create_data_ref (edge nest, loop_p loop, tree memref, gimple *stmt,
dr_analyze_innermost (&DR_INNERMOST (dr), memref,
nest != NULL ? loop : NULL, stmt);
- dr_analyze_indices (dr, nest, loop);
+ dr_analyze_indices (&dr->indices, DR_REF (dr), nest, loop);
dr_analyze_alias (dr);
if (dump_file && (dump_flags & TDF_DETAILS))
@@ -3066,41 +3065,30 @@ access_fn_components_comparable_p (tree ref_a, tree ref_b)
TREE_TYPE (TREE_OPERAND (ref_b, 0)));
}
-/* Initialize a data dependence relation between data accesses A and
- B. NB_LOOPS is the number of loops surrounding the references: the
- size of the classic distance/direction vectors. */
+/* Initialize a data dependence relation RES in LOOP_NEST. USE_ALT_INDICES
+ is true when the main indices of A and B were not comparable so we try again
+ with alternate indices computed on an indirect reference. */
struct data_dependence_relation *
-initialize_data_dependence_relation (struct data_reference *a,
- struct data_reference *b,
- vec<loop_p> loop_nest)
+initialize_data_dependence_relation (struct data_dependence_relation *res,
+ vec<loop_p> loop_nest,
+ bool use_alt_indices)
{
- struct data_dependence_relation *res;
+ struct data_reference *a = DDR_A (res);
+ struct data_reference *b = DDR_B (res);
unsigned int i;
- res = XCNEW (struct data_dependence_relation);
- DDR_A (res) = a;
- DDR_B (res) = b;
- DDR_LOOP_NEST (res).create (0);
- DDR_SUBSCRIPTS (res).create (0);
- DDR_DIR_VECTS (res).create (0);
- DDR_DIST_VECTS (res).create (0);
-
- if (a == NULL || b == NULL)
+ struct indices *indices_a = &a->indices;
+ struct indices *indices_b = &b->indices;
+ if (use_alt_indices)
{
- DDR_ARE_DEPENDENT (res) = chrec_dont_know;
- return res;
+ if (TREE_CODE (DR_REF (a)) != MEM_REF)
+ indices_a = &a->alt_indices;
+ if (TREE_CODE (DR_REF (b)) != MEM_REF)
+ indices_b = &b->alt_indices;
}
-
- /* If the data references do not alias, then they are independent. */
- if (!dr_may_alias_p (a, b, loop_nest.exists () ? loop_nest[0] : NULL))
- {
- DDR_ARE_DEPENDENT (res) = chrec_known;
- return res;
- }
-
- unsigned int num_dimensions_a = DR_NUM_DIMENSIONS (a);
- unsigned int num_dimensions_b = DR_NUM_DIMENSIONS (b);
+ unsigned int num_dimensions_a = indices_a->access_fns.length ();
+ unsigned int num_dimensions_b = indices_b->access_fns.length ();
if (num_dimensions_a == 0 || num_dimensions_b == 0)
{
DDR_ARE_DEPENDENT (res) = chrec_dont_know;
@@ -3125,9 +3113,9 @@ initialize_data_dependence_relation (struct data_reference *a,
the a and b accesses have a single ARRAY_REF component reference [0]
but have two subscripts. */
- if (DR_UNCONSTRAINED_BASE (a))
+ if (indices_a->unconstrained_base)
num_dimensions_a -= 1;
- if (DR_UNCONSTRAINED_BASE (b))
+ if (indices_b->unconstrained_base)
num_dimensions_b -= 1;
/* These structures describe sequences of component references in
@@ -3210,6 +3198,10 @@ initialize_data_dependence_relation (struct data_reference *a,
B: [3, 4] (i.e. s.e) */
while (index_a < num_dimensions_a && index_b < num_dimensions_b)
{
+ /* The alternate indices form always has a single dimension
+ with unconstrained base. */
+ gcc_assert (!use_alt_indices);
+
/* REF_A and REF_B must be one of the component access types
allowed by dr_analyze_indices. */
gcc_checking_assert (access_fn_component_p (ref_a));
@@ -3280,11 +3272,12 @@ initialize_data_dependence_relation (struct data_reference *a,
/* See whether FULL_SEQ ends at the base and whether the two bases
are equal. We do not care about TBAA or alignment info so we can
use OEP_ADDRESS_OF to avoid false negatives. */
- tree base_a = DR_BASE_OBJECT (a);
- tree base_b = DR_BASE_OBJECT (b);
+ tree base_a = indices_a->base_object;
+ tree base_b = indices_b->base_object;
bool same_base_p = (full_seq.start_a + full_seq.length == num_dimensions_a
&& full_seq.start_b + full_seq.length == num_dimensions_b
- && DR_UNCONSTRAINED_BASE (a) == DR_UNCONSTRAINED_BASE (b)
+ && (indices_a->unconstrained_base
+ == indices_b->unconstrained_base)
&& operand_equal_p (base_a, base_b, OEP_ADDRESS_OF)
&& (types_compatible_p (TREE_TYPE (base_a),
TREE_TYPE (base_b))
@@ -3323,7 +3316,7 @@ initialize_data_dependence_relation (struct data_reference *a,
both lvalues are distinct from the object's declared type. */
if (same_base_p)
{
- if (DR_UNCONSTRAINED_BASE (a))
+ if (indices_a->unconstrained_base)
full_seq.length += 1;
}
else
@@ -3332,8 +3325,41 @@ initialize_data_dependence_relation (struct data_reference *a,
/* Punt if we didn't find a suitable sequence. */
if (full_seq.length == 0)
{
- DDR_ARE_DEPENDENT (res) = chrec_dont_know;
- return res;
+ if (use_alt_indices
+ || (TREE_CODE (DR_REF (a)) == MEM_REF
+ && TREE_CODE (DR_REF (b)) == MEM_REF)
+ || may_be_nonaddressable_p (DR_REF (a))
+ || may_be_nonaddressable_p (DR_REF (b)))
+ {
+ /* Fully exhausted possibilities. */
+ DDR_ARE_DEPENDENT (res) = chrec_dont_know;
+ return res;
+ }
+
+ /* Try evaluating both DRs as dereferences of pointers. */
+ if (!a->alt_indices.base_object
+ && TREE_CODE (DR_REF (a)) != MEM_REF)
+ {
+ tree alt_ref = build2 (MEM_REF, TREE_TYPE (DR_REF (a)),
+ build1 (ADDR_EXPR, ptr_type_node, DR_REF (a)),
+ build_int_cst
+ (reference_alias_ptr_type (DR_REF (a)), 0));
+ dr_analyze_indices (&a->alt_indices, alt_ref,
+ loop_preheader_edge (loop_nest[0]),
+ loop_containing_stmt (DR_STMT (a)));
+ }
+ if (!b->alt_indices.base_object
+ && TREE_CODE (DR_REF (b)) != MEM_REF)
+ {
+ tree alt_ref = build2 (MEM_REF, TREE_TYPE (DR_REF (b)),
+ build1 (ADDR_EXPR, ptr_type_node, DR_REF (b)),
+ build_int_cst
+ (reference_alias_ptr_type (DR_REF (b)), 0));
+ dr_analyze_indices (&b->alt_indices, alt_ref,
+ loop_preheader_edge (loop_nest[0]),
+ loop_containing_stmt (DR_STMT (b)));
+ }
+ return initialize_data_dependence_relation (res, loop_nest, true);
}
if (!same_base_p)
@@ -3381,8 +3407,8 @@ initialize_data_dependence_relation (struct data_reference *a,
struct subscript *subscript;
subscript = XNEW (struct subscript);
- SUB_ACCESS_FN (subscript, 0) = DR_ACCESS_FN (a, full_seq.start_a + i);
- SUB_ACCESS_FN (subscript, 1) = DR_ACCESS_FN (b, full_seq.start_b + i);
+ SUB_ACCESS_FN (subscript, 0) = indices_a->access_fns[full_seq.start_a + i];
+ SUB_ACCESS_FN (subscript, 1) = indices_b->access_fns[full_seq.start_b + i];
SUB_CONFLICTS_IN_A (subscript) = conflict_fn_not_known ();
SUB_CONFLICTS_IN_B (subscript) = conflict_fn_not_known ();
SUB_LAST_CONFLICT (subscript) = chrec_dont_know;
@@ -3393,6 +3419,40 @@ initialize_data_dependence_relation (struct data_reference *a,
return res;
}
+/* Initialize a data dependence relation between data accesses A and
+ B. NB_LOOPS is the number of loops surrounding the references: the
+ size of the classic distance/direction vectors. */
+
+struct data_dependence_relation *
+initialize_data_dependence_relation (struct data_reference *a,
+ struct data_reference *b,
+ vec<loop_p> loop_nest)
+{
+ data_dependence_relation *res = XCNEW (struct data_dependence_relation);
+ DDR_A (res) = a;
+ DDR_B (res) = b;
+ DDR_LOOP_NEST (res).create (0);
+ DDR_SUBSCRIPTS (res).create (0);
+ DDR_DIR_VECTS (res).create (0);
+ DDR_DIST_VECTS (res).create (0);
+
+ if (a == NULL || b == NULL)
+ {
+ DDR_ARE_DEPENDENT (res) = chrec_dont_know;
+ return res;
+ }
+
+ /* If the data references do not alias, then they are independent. */
+ if (!dr_may_alias_p (a, b, loop_nest.exists () ? loop_nest[0] : NULL))
+ {
+ DDR_ARE_DEPENDENT (res) = chrec_known;
+ return res;
+ }
+
+ return initialize_data_dependence_relation (res, loop_nest, false);
+}
+
+
/* Frees memory used by the conflict function F. */
static void
diff --git a/gcc/tree-data-ref.h b/gcc/tree-data-ref.h
index 685f33d85ae..74f579c9f3f 100644
--- a/gcc/tree-data-ref.h
+++ b/gcc/tree-data-ref.h
@@ -166,14 +166,19 @@ struct data_reference
and runs to completion. */
bool is_conditional_in_stmt;
+ /* Alias information for the data reference. */
+ struct dr_alias alias;
+
/* Behavior of the memory reference in the innermost loop. */
struct innermost_loop_behavior innermost;
/* Subscripts of this data reference. */
struct indices indices;
- /* Alias information for the data reference. */
- struct dr_alias alias;
+ /* Alternate subscripts initialized lazily and used by data-dependence
+ analysis only when the main indices of two DRs are not comparable.
+ Keep last to keep vec_info_shared::check_datarefs happy. */
+ struct indices alt_indices;
};
#define DR_STMT(DR) (DR)->stmt
diff --git a/gcc/tree-vectorizer.c b/gcc/tree-vectorizer.c
index 3aa3e2a6783..20daa31187d 100644
--- a/gcc/tree-vectorizer.c
+++ b/gcc/tree-vectorizer.c
@@ -507,7 +507,8 @@ vec_info_shared::check_datarefs ()
return;
gcc_assert (datarefs.length () == datarefs_copy.length ());
for (unsigned i = 0; i < datarefs.length (); ++i)
- if (memcmp (&datarefs_copy[i], datarefs[i], sizeof (data_reference)) != 0)
+ if (memcmp (&datarefs_copy[i], datarefs[i],
+ offsetof (data_reference, alt_indices)) != 0)
gcc_unreachable ();
}
</cut>
After llvm commit 669ddd1e9b1226432b003dbba05b99f8e992285b
Author: Arthur Eubanks <aeubanks(a)google.com>
Turn on the new pass manager by default
the following benchmarks grew in size by more than 1%:
- 403.gcc grew in size by 2% from 2586180 to 2648252 bytes
Below reproducer instructions can be used to re-build both "first_bad" and "last_good" cross-toolchains used in this bisection. Naturally, the scripts will fail when triggerring benchmarking jobs if you don't have access to Linaro TCWG CI.
For your convenience, we have uploaded tarballs with pre-processed source and assembly files at:
- First_bad save-temps: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release…
- Last_good save-temps: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release…
- Baseline save-temps: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release…
Configuration:
- Benchmark: SPEC CPU2006
- Toolchain: Clang + Glibc + LLVM Linker
- Version: all components were built from their latest release branch
- Target: aarch64-linux-gnu
- Compiler flags: -Os -flto
- Hardware: APM Mustang 8x X-Gene1
This benchmarking CI is work-in-progress, and we welcome feedback and suggestions at linaro-toolchain(a)lists.linaro.org . In our improvement plans is to add support for SPEC CPU2017 benchmarks and provide "perf report/annotate" data behind these reports.
THIS IS THE END OF INTERESTING STUFF. BELOW ARE LINKS TO BUILDS, REPRODUCTION INSTRUCTIONS, AND THE RAW COMMIT.
This commit has regressed these CI configurations:
- tcwg_bmk_llvm_apm/llvm-release-aarch64-spec2k6-Os_LTO
First_bad build: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release…
Last_good build: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release…
Baseline build: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release…
Even more details: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release…
Reproduce builds:
<cut>
mkdir investigate-llvm-669ddd1e9b1226432b003dbba05b99f8e992285b
cd investigate-llvm-669ddd1e9b1226432b003dbba05b99f8e992285b
# Fetch scripts
git clone https://git.linaro.org/toolchain/jenkins-scripts
# Fetch manifests and test.sh script
mkdir -p artifacts/manifests
curl -o artifacts/manifests/build-baseline.sh https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release… --fail
curl -o artifacts/manifests/build-parameters.sh https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release… --fail
curl -o artifacts/test.sh https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release… --fail
chmod +x artifacts/test.sh
# Reproduce the baseline build (build all pre-requisites)
./jenkins-scripts/tcwg_bmk-build.sh @@ artifacts/manifests/build-baseline.sh
# Save baseline build state (which is then restored in artifacts/test.sh)
mkdir -p ./bisect
rsync -a --del --delete-excluded --exclude /bisect/ --exclude /artifacts/ --exclude /llvm/ ./ ./bisect/baseline/
cd llvm
# Reproduce first_bad build
git checkout --detach 669ddd1e9b1226432b003dbba05b99f8e992285b
../artifacts/test.sh
# Reproduce last_good build
git checkout --detach b15cbaf5a03d0b32dbc32c37766e32ccf66e6c87
../artifacts/test.sh
cd ..
</cut>
Full commit (up to 1000 lines):
<cut>
commit 669ddd1e9b1226432b003dbba05b99f8e992285b
Author: Arthur Eubanks <aeubanks(a)google.com>
Date: Mon Jan 25 11:00:56 2021 -0800
Turn on the new pass manager by default
This turns on the new pass manager by default for the optimization pipeline in
Clang and ThinLTO in various LLD backends. This also makes uses of `opt
-instcombine` use the new pass manager (unless specifically opted out).
This does not affect the backend target-dependent codegen pipeline.
If this causes regressions, you can opt out of the new pass manager
either via the -DENABLE_EXPERIMENTAL_NEW_PASS_MANAGER=OFF CMake flag
while building LLVM, or via various compiler flags, e.g.
-flegacy-pass-manager for Clang or -Wl,--lto-legacy-pass-manager for
ELF LLD. Please file bugs for any regressions.
Major differences:
* The inliner works slightly differently
* -O1 does some amount of inlining
* LCSSA and LoopSimplify are run before all loop passes
* Loop unswitching is implemented slightly differently
* A new SpeculateAroundPHIs pass is added to the pipeline
https://lists.llvm.org/pipermail/llvm-dev/2021-January/148098.html
Reviewed By: asbirlea, ychen, MaskRay, echristo
Differential Revision: https://reviews.llvm.org/D95380
---
llvm/CMakeLists.txt | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index 1affc289e64b..f5298de9f7ca 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -688,8 +688,8 @@ else()
endif()
option(LLVM_ENABLE_PLUGINS "Enable plugin support" ${LLVM_ENABLE_PLUGINS_default})
-set(ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER FALSE CACHE BOOL
- "Enable the experimental new pass manager by default.")
+set(ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER TRUE CACHE BOOL
+ "Enable the new pass manager by default.")
include(HandleLLVMOptions)
</cut>