* [Bug other/111559] [14 regression] ICE when building Python with PGO
2023-09-23 21:42 [Bug other/111559] New: [14 regression] ICE when building Python with PGO sjames at gcc dot gnu.org
@ 2023-09-23 21:48 ` sjames at gcc dot gnu.org
2023-09-23 21:49 ` [Bug gcov-profile/111559] " pinskia at gcc dot gnu.org
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From: sjames at gcc dot gnu.org @ 2023-09-23 21:48 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111559
--- Comment #1 from Sam James <sjames at gcc dot gnu.org> ---
I don't think I'm going to be able to get a minimal reproducer for this, but
trying to at least get something a bit smaller/precise.
If I take inspiration from PR79587, I can do a bit better:
* wget https://www.python.org/ftp/python/3.11.5/Python-3.11.5.tar.xz
* tar xvf Python-3.11.5.tar.xz
* ./configure CC=gcc-14 --enable-optimizations
* make clean
* make profile-removal
* make build_all_generate_profile
* make profile-removal
* make run_profile_task # unfortunately this runs something like 44 different
Python tests
* make build_all_merge_profile
* gcc-14 -c -fno-strict-overflow -Wsign-compare -DDYNAMIC_ANNOTATIONS_ENABLED=1
-DNDEBUG -O2 -pipe -march=native -fdiagnostics-color=always
-frecord-gcc-switches -Wreturn-type -ggdb3 -fwrapv -fno-semantic-interposition
-std=c11 -Wextra -Wno-unused-parameter -Wno-missing-field-initializers
-Wstrict-prototypes -Werror=implicit-function-declaration -fvisibility=hidden
-fprofile-use -fprofile-correction -I./Include/internal -I. -I./Include
-I/usr/include/ncursesw -fPIC -DPy_BUILD_CORE -o Parser/parser.o
Parser/parser.c -save-temps
```
gcc-14 -c -fno-strict-overflow -Wsign-compare -DDYNAMIC_ANNOTATIONS_ENABLED=1
-DNDEBUG -O2 -pipe -fdiagnostics-color=always -frecord-gcc-switches
-Wreturn-type -ggdb3 -fwrapv -fno-semantic-interposition -std=c11 -Wextra
-Wno-unused-parameter -Wno-missing-field-initializers -Wstrict-prototypes
-Werror=implicit-function-declaration -fvisibility=hidden -fprofile-use
-fprofile-correction -I./Include/internal -I. -I./Include
-I/usr/include/ncursesw -fPIC -DPy_BUILD_CORE -o Parser/parser.o
Parser/parser.c -save-temps
gcc-14: warning: ‘-pipe’ ignored because ‘-save-temps’ specified
Parser/parser.c: In function ‘_tmp_28_rule’:
Parser/parser.c:25179:1: error: probability of edge 3->4 not initialized
25179 | _tmp_28_rule(Parser *p)
| ^~~~~~~~~~~~
Parser/parser.c:25179:1: error: probability of edge 5->11 not initialized
during GIMPLE pass: fixup_cfg
Parser/parser.c:25179:1: internal compiler error: verify_flow_info failed
0x55b70ce37153 verify_flow_info()
/usr/src/debug/sys-devel/gcc-14.0.0_pre20230917/gcc-14-20230917/gcc/cfghooks.cc:287
0x55b70d295897 execute_function_todo
/usr/src/debug/sys-devel/gcc-14.0.0_pre20230917/gcc-14-20230917/gcc/passes.cc:2100
0x55b70d295e10 execute_todo
/usr/src/debug/sys-devel/gcc-14.0.0_pre20230917/gcc-14-20230917/gcc/passes.cc:2142
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://bugs.gentoo.org/> for instructions.
```
```
$ gcc-14 -v
Using built-in specs.
COLLECT_GCC=gcc-14
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/14/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with:
/var/tmp/portage/sys-devel/gcc-14.0.0_pre20230917/work/gcc-14-20230917/configure
--host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr
--bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/14
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/14/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/14
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/14/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/14/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/14/include/g++-v14
--disable-silent-rules --disable-dependency-tracking
--with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/14/python
--enable-languages=c,c++,fortran,rust --enable-obsolete --enable-secureplt
--disable-werror --with-system-zlib --enable-nls --without-included-gettext
--disable-libunwind-exceptions --enable-checking=yes,extra,rtl
--with-bugurl=https://bugs.gentoo.org/ --with-pkgversion='Gentoo Hardened
14.0.0_pre20230917 p2' --with-gcc-major-version-only --enable-libstdcxx-time
--enable-lto --disable-libstdcxx-pch --enable-shared --enable-threads=posix
--enable-__cxa_atexit --enable-clocale=gnu --enable-multilib
--with-multilib-list=m32,m64 --disable-fixed-point --enable-targets=all
--enable-libgomp --disable-libssp --disable-libada --enable-cet
--disable-systemtap --enable-valgrind-annotations --disable-vtable-verify
--disable-libvtv --with-zstd --with-isl --disable-isl-version-check
--enable-default-pie --enable-host-pie --enable-host-bind-now
--enable-default-ssp --with-build-config=bootstrap-cet
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 14.0.0 20230917 (experimental) (Gentoo Hardened 14.0.0_pre20230917
p2)
```
I've uploaded build dir after running that last command at
https://dev.gentoo.org/~sam/bugs/gcc/gcc-python-pgo-x86/Python-3.11.5-pgo-crash.tar.xz.
^ permalink raw reply [flat|nested] 12+ messages in thread* [Bug gcov-profile/111559] [14 regression] ICE when building Python with PGO
2023-09-23 21:42 [Bug other/111559] New: [14 regression] ICE when building Python with PGO sjames at gcc dot gnu.org
2023-09-23 21:48 ` [Bug other/111559] " sjames at gcc dot gnu.org
@ 2023-09-23 21:49 ` pinskia at gcc dot gnu.org
2023-09-24 9:03 ` slyfox at gcc dot gnu.org
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From: pinskia at gcc dot gnu.org @ 2023-09-23 21:49 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111559
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |hubicka at gcc dot gnu.org
Target Milestone|--- |14.0
^ permalink raw reply [flat|nested] 12+ messages in thread* [Bug gcov-profile/111559] [14 regression] ICE when building Python with PGO
2023-09-23 21:42 [Bug other/111559] New: [14 regression] ICE when building Python with PGO sjames at gcc dot gnu.org
2023-09-23 21:48 ` [Bug other/111559] " sjames at gcc dot gnu.org
2023-09-23 21:49 ` [Bug gcov-profile/111559] " pinskia at gcc dot gnu.org
@ 2023-09-24 9:03 ` slyfox at gcc dot gnu.org
2023-09-24 9:15 ` sirl at gcc dot gnu.org
` (7 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: slyfox at gcc dot gnu.org @ 2023-09-24 9:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111559
Sergei Trofimovich <slyfox at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |slyfox at gcc dot gnu.org
--- Comment #2 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
Possibly exposed by r14-3459-g0c78240fd7d519 "Check that passes do not forget
to define profile"
^ permalink raw reply [flat|nested] 12+ messages in thread* [Bug gcov-profile/111559] [14 regression] ICE when building Python with PGO
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` (2 preceding siblings ...)
2023-09-24 9:03 ` slyfox at gcc dot gnu.org
@ 2023-09-24 9:15 ` sirl at gcc dot gnu.org
2023-09-27 8:03 ` slyfox at gcc dot gnu.org
` (6 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: sirl at gcc dot gnu.org @ 2023-09-24 9:15 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111559
Franz Sirl <sirl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |sirl at gcc dot gnu.org
--- Comment #3 from Franz Sirl <sirl at gcc dot gnu.org> ---
Looks like a dup of the profiledbootstrap fail bug 111283
^ permalink raw reply [flat|nested] 12+ messages in thread* [Bug gcov-profile/111559] [14 regression] ICE when building Python with PGO
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2023-09-24 9:15 ` sirl at gcc dot gnu.org
@ 2023-09-27 8:03 ` slyfox at gcc dot gnu.org
2023-09-27 8:11 ` slyfox at gcc dot gnu.org
` (5 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: slyfox at gcc dot gnu.org @ 2023-09-27 8:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111559
--- Comment #4 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
Looks like identical code folding creates uninitialized profile counters if
there are any edges in folded functions.
I think cvise did a decent job extracting the reproducer below. Here is a
single-file trigger on `--enable-checking=yes` `gcc` from `master`:
```
// $ cat bug.c
__attribute__((noipa)) static void edge(void) {}
static void rule1(int *p) {
edge();
if (*p) edge();
}
static void rule1_same(int *p) {
edge();
if (*p) edge();
}
__attribute__((noipa)) int main(void) {
int p = 0;
rule1(&p);
rule1_same(&p);
}
```
Trigger:
```
$ echo PG
$ gcc -O2 -fprofile-generate bug.c -o b -fopt-info
$ echo RUN
$ ./b
$ echo PU
$ gcc -O2 -fprofile-use -fprofile-correction bug.c -o b -fopt-info
```
Running:
```
PG
$ gcc -O2 -fprofile-generate bug.c -o b -fopt-info
bug.c:15:5: optimized: Inlined rule1.constprop/28 into main/3 which now has
time 75.280000 and size 51, net change of -6.
bug.c:16:5: optimized: Inlined rule1_same.constprop/27 into main/3 which now
has time 94.560000 and size 72, net change of -6.
RUN
$ ./b
PU
$ gcc -O2 -fprofile-use -fprofile-correction bug.c -o b -fopt-info
bug.c:3:13: optimized: Semantic equality hit:rule1/1->rule1_same/2
bug.c:3:13: optimized: Assembler symbol names:rule1/1->rule1_same/2
bug.c:15:5: optimized: Inlined rule1.constprop/5 into main/3 which now has
time 26.000000 and size 10, net change of +2.
bug.c:16:5: optimized: Inlined rule1.constprop/4 into main/3 which now has
time 27.000000 and size 12, net change of -6.
bug.c: In function 'main':
bug.c:13:28: error: probability of edge 3->4 not initialized
13 | __attribute__((noipa)) int main(void) {
| ^~~~
bug.c:13:28: error: probability of edge 5->6 not initialized
during IPA pass: inline
bug.c:13:28: internal compiler error: verify_flow_info failed
```
^ permalink raw reply [flat|nested] 12+ messages in thread* [Bug gcov-profile/111559] [14 regression] ICE when building Python with PGO
2023-09-23 21:42 [Bug other/111559] New: [14 regression] ICE when building Python with PGO sjames at gcc dot gnu.org
` (4 preceding siblings ...)
2023-09-27 8:03 ` slyfox at gcc dot gnu.org
@ 2023-09-27 8:11 ` slyfox at gcc dot gnu.org
2023-09-27 13:21 ` slyfox at gcc dot gnu.org
` (4 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: slyfox at gcc dot gnu.org @ 2023-09-27 8:11 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111559
--- Comment #5 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
Slightly shorter example that does not rely on inline:
// $ cat bug.c
__attribute__((noipa)) static void edge(void) {}
int p = 0;
__attribute__((noinline))
static void rule1(void) { if (p) edge(); }
__attribute__((noinline))
static void rule1_same(void) { if (p) edge(); }
__attribute__((noipa)) int main(void) {
rule1();
rule1_same();
}
bug.c: In function 'rule1':
bug.c:6:13: error: probability of edge 3->4 not initialized
6 | static void rule1(void) { if (p) edge(); }
| ^~~~~
during GIMPLE pass: fixup_cfg
bug.c:6:13: internal compiler error: verify_flow_info failed
^ permalink raw reply [flat|nested] 12+ messages in thread* [Bug gcov-profile/111559] [14 regression] ICE when building Python with PGO
2023-09-23 21:42 [Bug other/111559] New: [14 regression] ICE when building Python with PGO sjames at gcc dot gnu.org
` (5 preceding siblings ...)
2023-09-27 8:11 ` slyfox at gcc dot gnu.org
@ 2023-09-27 13:21 ` slyfox at gcc dot gnu.org
2023-09-27 14:46 ` slyfox at gcc dot gnu.org
` (3 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: slyfox at gcc dot gnu.org @ 2023-09-27 13:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111559
--- Comment #6 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
Uninitialized value comes from `ipa_merge_profiles()` for our `rule1_same()`
alias and `rule1()` functions:
// in gcc/ipa-icf.cc:
else if (create_alias)
{
alias->icf_merged = true;
/* Remove the function's body. */
ipa_merge_profiles (original, alias);
// ...
If I comment out `ipa_merge_profiles (original, alias);` call to leave
`original` as is then failure does not happen. Which means at least
`original`'s profile is fine.
Tracing through `ipa_merge_profiles()` we generate uninitialized probalility
profile when divide by zero at:
// in gcc/ipa-utils.cc
void
ipa_merge_profiles (struct cgraph_node *dst,
struct cgraph_node *src,
bool preserve_body)
// ...
/* TODO: merge also statement histograms. */
FOR_ALL_BB_FN (srcbb, srccfun)
{
unsigned int i;
if (copy_counts) { /* snip: ireelevant */ }
else
{
for (i = 0; i < EDGE_COUNT (srcbb->succs); i++)
{
edge srce = EDGE_SUCC (srcbb, i);
edge dste = EDGE_SUCC (dstbb, i);
dste->probability =
dste->probability * dstbb->count.ipa ().probability_in
(dstbb->count.ipa ()
+ srccount.ipa ())
+ srce->probability * srcbb->count.ipa ().probability_in
(dstbb->count.ipa ()
+ srccount.ipa ());
}
dstbb->count = dstbb->count.ipa () + srccount.ipa ();
}
}
// ...
Here `dstbb->count.ipa () + srccount.ipa ()` is zero.
This assert should expose it as well:
--- a/gcc/ipa-utils.cc
+++ b/gcc/ipa-utils.cc
@@ -651,13 +651,15 @@ ipa_merge_profiles (struct cgraph_node *dst,
{
edge srce = EDGE_SUCC (srcbb, i);
edge dste = EDGE_SUCC (dstbb, i);
+
+ profile_count den = dstbb->count.ipa () + srccount.ipa ();
+ gcc_assert(den.nonzero_p());
+
dste->probability =
dste->probability * dstbb->count.ipa ().probability_in
- (dstbb->count.ipa ()
- + srccount.ipa ())
+ (den)
+ srce->probability * srcbb->count.ipa ().probability_in
- (dstbb->count.ipa ()
- + srccount.ipa ());
+ (den);
}
dstbb->count = dstbb->count.ipa () + srccount.ipa ();
}
If we attach `gdb` it agrees we exercise these edges 0 times.
(gdb) call dstbb->count.debug()
0 (precise)
(gdb) call srccount.ipa ().debug()
0 (precise)
For comparison we are trying to clobber `always` probability with `undefined`:
(gdb) call dste->probability.debug()
always
What edge is that?
(gdb) call debug_edge(srce)
edge (bb_3, bb_4)
__attribute__((noinline))
void rule1 ()
{
int p.0_1;
<bb 2> [count: 2]:
p.0_1 = p;
if (p.0_1 != 0)
goto <bb 3>; [0.00%]
else
goto <bb 4>; [100.00%]
<bb 3> [count: 0]:
edge ();
<bb 4> [count: 2]:
return;
}
`always` should valid for `bb_3->bb_4`. But for our data input it's `never`.
^ permalink raw reply [flat|nested] 12+ messages in thread* [Bug gcov-profile/111559] [14 regression] ICE when building Python with PGO
2023-09-23 21:42 [Bug other/111559] New: [14 regression] ICE when building Python with PGO sjames at gcc dot gnu.org
` (6 preceding siblings ...)
2023-09-27 13:21 ` slyfox at gcc dot gnu.org
@ 2023-09-27 14:46 ` slyfox at gcc dot gnu.org
2023-09-28 14:17 ` sirl at gcc dot gnu.org
` (2 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: slyfox at gcc dot gnu.org @ 2023-09-27 14:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111559
--- Comment #7 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
Proposed conservative fix as
https://gcc.gnu.org/pipermail/gcc-patches/2023-September/631526.html
^ permalink raw reply [flat|nested] 12+ messages in thread* [Bug gcov-profile/111559] [14 regression] ICE when building Python with PGO
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` (7 preceding siblings ...)
2023-09-27 14:46 ` slyfox at gcc dot gnu.org
@ 2023-09-28 14:17 ` sirl at gcc dot gnu.org
2023-10-05 16:14 ` cvs-commit at gcc dot gnu.org
2023-10-05 16:16 ` slyfox at gcc dot gnu.org
10 siblings, 0 replies; 12+ messages in thread
From: sirl at gcc dot gnu.org @ 2023-09-28 14:17 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111559
--- Comment #8 from Franz Sirl <sirl at gcc dot gnu.org> ---
The proposed patch on top of r14-4307 fixes the profiled bootstrap here.
^ permalink raw reply [flat|nested] 12+ messages in thread* [Bug gcov-profile/111559] [14 regression] ICE when building Python with PGO
2023-09-23 21:42 [Bug other/111559] New: [14 regression] ICE when building Python with PGO sjames at gcc dot gnu.org
` (8 preceding siblings ...)
2023-09-28 14:17 ` sirl at gcc dot gnu.org
@ 2023-10-05 16:14 ` cvs-commit at gcc dot gnu.org
2023-10-05 16:16 ` slyfox at gcc dot gnu.org
10 siblings, 0 replies; 12+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-10-05 16:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111559
--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Sergei Trofimovich <slyfox@gcc.gnu.org>:
https://gcc.gnu.org/g:043a6fcbc27f8721301eb2f72a7839f54f393003
commit r14-4421-g043a6fcbc27f8721301eb2f72a7839f54f393003
Author: Sergei Trofimovich <siarheit@google.com>
Date: Wed Sep 27 14:29:12 2023 +0100
ipa-utils: avoid uninitialized probabilities on ICF [PR111559]
r14-3459-g0c78240fd7d519 "Check that passes do not forget to define
profile"
exposed check failures in cases when gcc produces uninitialized profile
probabilities. In case of PR/111559 uninitialized profile is generated
by edges executed 0 times reported by IPA profile:
$ gcc -O2 -fprofile-generate pr111559.c -o b -fopt-info
$ ./b
$ gcc -O2 -fprofile-use -fprofile-correction pr111559.c -o b -fopt-info
pr111559.c: In function 'rule1':
pr111559.c:6:13: error: probability of edge 3->4 not initialized
6 | static void rule1(void) { if (p) edge(); }
| ^~~~~
during GIMPLE pass: fixup_cfg
pr111559.c:6:13: internal compiler error: verify_flow_info failed
The change conservatively ignores updates with zero execution counts and
uses initially assigned probabilities (`always` probability in case of
the example).
PR ipa/111283
PR gcov-profile/111559
gcc/
* ipa-utils.cc (ipa_merge_profiles): Avoid producing
uninitialized probabilities when merging counters with zero
denominators.
gcc/testsuite/
* gcc.dg/tree-prof/pr111559.c: New test.
^ permalink raw reply [flat|nested] 12+ messages in thread* [Bug gcov-profile/111559] [14 regression] ICE when building Python with PGO
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` (9 preceding siblings ...)
2023-10-05 16:14 ` cvs-commit at gcc dot gnu.org
@ 2023-10-05 16:16 ` slyfox at gcc dot gnu.org
10 siblings, 0 replies; 12+ messages in thread
From: slyfox at gcc dot gnu.org @ 2023-10-05 16:16 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111559
Sergei Trofimovich <slyfox at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |FIXED
Assignee|unassigned at gcc dot gnu.org |slyfox at gcc dot gnu.org
--- Comment #10 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
Fixed in master.
Thanks for the report!
^ permalink raw reply [flat|nested] 12+ messages in thread