* [PATCH] ipa-utils: avoid generating uninitialized probabilities on merges.
@ 2023-09-27 14:44 Sergei Trofimovich
2023-10-01 19:29 ` [PATCH v2] ipa-utils: avoid uninitialized probabilities on ICF [PR111559] Sergei Trofimovich
0 siblings, 1 reply; 7+ messages in thread
From: Sergei Trofimovich @ 2023-09-27 14:44 UTC (permalink / raw)
To: gcc-patches, Jan Hubicka, Richard Biener; +Cc: Sergei Trofimovich
From: Sergei Trofimovich <siarheit@google.com>
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 during profile:
__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();
}
$ gcc -O2 -fprofile-generate bug.c -o b -fopt-info
$ ./b
$ gcc -O2 -fprofile-use -fprofile-correction bug.c -o b -fopt-info
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
The change conservatively ignores updates with uninitialized values and
uses initially assigned probabilities (`always` probability in case of
the example).
gcc/
PR/111283
PR/111559
* ipa-utils.cc (ipa_merge_profiles): Avoid producing
uninitialized probabilities when merging counters with zero
denominators.
---
gcc/ipa-utils.cc | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/gcc/ipa-utils.cc b/gcc/ipa-utils.cc
index 956c6294fd7..7c53ae9dd45 100644
--- a/gcc/ipa-utils.cc
+++ b/gcc/ipa-utils.cc
@@ -651,13 +651,17 @@ ipa_merge_profiles (struct cgraph_node *dst,
{
edge srce = EDGE_SUCC (srcbb, i);
edge dste = EDGE_SUCC (dstbb, i);
- dste->probability =
+ profile_probability merged =
dste->probability * dstbb->count.ipa ().probability_in
(dstbb->count.ipa ()
+ srccount.ipa ())
+ srce->probability * srcbb->count.ipa ().probability_in
(dstbb->count.ipa ()
+ srccount.ipa ());
+ /* We produce uninitialized probabilities when
+ denominator is zero: https://gcc.gnu.org/PR111559. */
+ if (merged.initialized_p ())
+ dste->probability = merged;
}
dstbb->count = dstbb->count.ipa () + srccount.ipa ();
}
--
2.42.0
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2] ipa-utils: avoid uninitialized probabilities on ICF [PR111559]
2023-09-27 14:44 [PATCH] ipa-utils: avoid generating uninitialized probabilities on merges Sergei Trofimovich
@ 2023-10-01 19:29 ` Sergei Trofimovich
2023-10-05 11:52 ` Jan Hubicka
0 siblings, 1 reply; 7+ messages in thread
From: Sergei Trofimovich @ 2023-10-01 19:29 UTC (permalink / raw)
To: gcc-patches; +Cc: slyich, hubicka, rguenther, siarheit
From: Sergei Trofimovich <siarheit@google.com>
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 uninitialized values 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.
---
gcc/ipa-utils.cc | 6 +++++-
gcc/testsuite/gcc.dg/tree-prof/pr111559.c | 16 ++++++++++++++++
2 files changed, 21 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-prof/pr111559.c
diff --git a/gcc/ipa-utils.cc b/gcc/ipa-utils.cc
index 956c6294fd7..7c53ae9dd45 100644
--- a/gcc/ipa-utils.cc
+++ b/gcc/ipa-utils.cc
@@ -651,13 +651,17 @@ ipa_merge_profiles (struct cgraph_node *dst,
{
edge srce = EDGE_SUCC (srcbb, i);
edge dste = EDGE_SUCC (dstbb, i);
- dste->probability =
+ profile_probability merged =
dste->probability * dstbb->count.ipa ().probability_in
(dstbb->count.ipa ()
+ srccount.ipa ())
+ srce->probability * srcbb->count.ipa ().probability_in
(dstbb->count.ipa ()
+ srccount.ipa ());
+ /* We produce uninitialized probabilities when
+ denominator is zero: https://gcc.gnu.org/PR111559. */
+ if (merged.initialized_p ())
+ dste->probability = merged;
}
dstbb->count = dstbb->count.ipa () + srccount.ipa ();
}
diff --git a/gcc/testsuite/gcc.dg/tree-prof/pr111559.c b/gcc/testsuite/gcc.dg/tree-prof/pr111559.c
new file mode 100644
index 00000000000..43202c6c888
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-prof/pr111559.c
@@ -0,0 +1,16 @@
+/* { dg-options "-O2" } */
+
+__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();
+}
--
2.42.0
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] ipa-utils: avoid uninitialized probabilities on ICF [PR111559]
2023-10-01 19:29 ` [PATCH v2] ipa-utils: avoid uninitialized probabilities on ICF [PR111559] Sergei Trofimovich
@ 2023-10-05 11:52 ` Jan Hubicka
2023-10-05 12:46 ` Sergei Trofimovich
0 siblings, 1 reply; 7+ messages in thread
From: Jan Hubicka @ 2023-10-05 11:52 UTC (permalink / raw)
To: Sergei Trofimovich; +Cc: gcc-patches, rguenther, siarheit
> From: Sergei Trofimovich <siarheit@google.com>
>
> 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 uninitialized values 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.
> ---
> gcc/ipa-utils.cc | 6 +++++-
> gcc/testsuite/gcc.dg/tree-prof/pr111559.c | 16 ++++++++++++++++
> 2 files changed, 21 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/gcc.dg/tree-prof/pr111559.c
>
> diff --git a/gcc/ipa-utils.cc b/gcc/ipa-utils.cc
> index 956c6294fd7..7c53ae9dd45 100644
> --- a/gcc/ipa-utils.cc
> +++ b/gcc/ipa-utils.cc
> @@ -651,13 +651,17 @@ ipa_merge_profiles (struct cgraph_node *dst,
> {
> edge srce = EDGE_SUCC (srcbb, i);
> edge dste = EDGE_SUCC (dstbb, i);
> - dste->probability =
> + profile_probability merged =
> dste->probability * dstbb->count.ipa ().probability_in
> (dstbb->count.ipa ()
> + srccount.ipa ())
> + srce->probability * srcbb->count.ipa ().probability_in
> (dstbb->count.ipa ()
> + srccount.ipa ());
> + /* We produce uninitialized probabilities when
> + denominator is zero: https://gcc.gnu.org/PR111559. */
> + if (merged.initialized_p ())
> + dste->probability = merged;
Thanks for the patch.
We usually avoid the uninitialized value here by simply checking that
parameter of probability_in satifies nonzero_p. So I think it would be
more consistent doing it here to:
profile_probability sum = dstbb->count.ipa () + srccount.ipa ()
if (sum.nonzero_p ())
{
dste->probability = .....
}
OK with this change.
Honza
> }
> dstbb->count = dstbb->count.ipa () + srccount.ipa ();
> }
> diff --git a/gcc/testsuite/gcc.dg/tree-prof/pr111559.c b/gcc/testsuite/gcc.dg/tree-prof/pr111559.c
> new file mode 100644
> index 00000000000..43202c6c888
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-prof/pr111559.c
> @@ -0,0 +1,16 @@
> +/* { dg-options "-O2" } */
> +
> +__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();
> +}
> --
> 2.42.0
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] ipa-utils: avoid uninitialized probabilities on ICF [PR111559]
2023-10-05 11:52 ` Jan Hubicka
@ 2023-10-05 12:46 ` Sergei Trofimovich
2023-10-05 13:04 ` Jan Hubicka
0 siblings, 1 reply; 7+ messages in thread
From: Sergei Trofimovich @ 2023-10-05 12:46 UTC (permalink / raw)
To: Jan Hubicka; +Cc: gcc-patches, rguenther, siarheit
[-- Attachment #1: Type: text/plain, Size: 3744 bytes --]
On Thu, Oct 05, 2023 at 01:52:30PM +0200, Jan Hubicka wrote:
> > From: Sergei Trofimovich <siarheit@google.com>
> >
> > 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 uninitialized values 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.
> > ---
> > gcc/ipa-utils.cc | 6 +++++-
> > gcc/testsuite/gcc.dg/tree-prof/pr111559.c | 16 ++++++++++++++++
> > 2 files changed, 21 insertions(+), 1 deletion(-)
> > create mode 100644 gcc/testsuite/gcc.dg/tree-prof/pr111559.c
> >
> > diff --git a/gcc/ipa-utils.cc b/gcc/ipa-utils.cc
> > index 956c6294fd7..7c53ae9dd45 100644
> > --- a/gcc/ipa-utils.cc
> > +++ b/gcc/ipa-utils.cc
> > @@ -651,13 +651,17 @@ ipa_merge_profiles (struct cgraph_node *dst,
> > {
> > edge srce = EDGE_SUCC (srcbb, i);
> > edge dste = EDGE_SUCC (dstbb, i);
> > - dste->probability =
> > + profile_probability merged =
> > dste->probability * dstbb->count.ipa ().probability_in
> > (dstbb->count.ipa ()
> > + srccount.ipa ())
> > + srce->probability * srcbb->count.ipa ().probability_in
> > (dstbb->count.ipa ()
> > + srccount.ipa ());
> > + /* We produce uninitialized probabilities when
> > + denominator is zero: https://gcc.gnu.org/PR111559. */
> > + if (merged.initialized_p ())
> > + dste->probability = merged;
>
> Thanks for the patch.
> We usually avoid the uninitialized value here by simply checking that
> parameter of probability_in satifies nonzero_p. So I think it would be
> more consistent doing it here to:
>
> profile_probability sum = dstbb->count.ipa () + srccount.ipa ()
> if (sum.nonzero_p ())
> {
> dste->probability = .....
> }
Aha, sounds good! I had to do `s/profile_probability/profile_count` as
it's a denominator value for probability.
Attached v3 just in case.
> OK with this change.
> Honza
> > }
> > dstbb->count = dstbb->count.ipa () + srccount.ipa ();
> > }
> > diff --git a/gcc/testsuite/gcc.dg/tree-prof/pr111559.c b/gcc/testsuite/gcc.dg/tree-prof/pr111559.c
> > new file mode 100644
> > index 00000000000..43202c6c888
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/tree-prof/pr111559.c
> > @@ -0,0 +1,16 @@
> > +/* { dg-options "-O2" } */
> > +
> > +__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();
> > +}
> > --
> > 2.42.0
> >
--
Sergei
[-- Attachment #2: v3-0001-ipa-utils-avoid-uninitialized-probabilities-on-IC.patch --]
[-- Type: text/plain, Size: 3166 bytes --]
From 97122ebae5a7ed43b6c31574c761a54bee3a96ec Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <siarheit@google.com>
Date: Wed, 27 Sep 2023 14:29:12 +0100
Subject: [PATCH v3] 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.
---
gcc/ipa-utils.cc | 17 ++++++++++-------
gcc/testsuite/gcc.dg/tree-prof/pr111559.c | 16 ++++++++++++++++
2 files changed, 26 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-prof/pr111559.c
diff --git a/gcc/ipa-utils.cc b/gcc/ipa-utils.cc
index 956c6294fd7..1355ccac6f0 100644
--- a/gcc/ipa-utils.cc
+++ b/gcc/ipa-utils.cc
@@ -651,13 +651,16 @@ ipa_merge_profiles (struct cgraph_node *dst,
{
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 ());
+ profile_count sum =
+ dstbb->count.ipa () + srccount.ipa ();
+ if (sum.nonzero_p ())
+ 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 ();
}
diff --git a/gcc/testsuite/gcc.dg/tree-prof/pr111559.c b/gcc/testsuite/gcc.dg/tree-prof/pr111559.c
new file mode 100644
index 00000000000..43202c6c888
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-prof/pr111559.c
@@ -0,0 +1,16 @@
+/* { dg-options "-O2" } */
+
+__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();
+}
--
2.42.0
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] ipa-utils: avoid uninitialized probabilities on ICF [PR111559]
2023-10-05 12:46 ` Sergei Trofimovich
@ 2023-10-05 13:04 ` Jan Hubicka
2023-10-05 13:11 ` [PATCH v4] " Sergei Trofimovich
0 siblings, 1 reply; 7+ messages in thread
From: Jan Hubicka @ 2023-10-05 13:04 UTC (permalink / raw)
To: Sergei Trofimovich; +Cc: gcc-patches, rguenther, siarheit
> diff --git a/gcc/ipa-utils.cc b/gcc/ipa-utils.cc
> index 956c6294fd7..1355ccac6f0 100644
> --- a/gcc/ipa-utils.cc
> +++ b/gcc/ipa-utils.cc
> @@ -651,13 +651,16 @@ ipa_merge_profiles (struct cgraph_node *dst,
> {
> 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 ());
> + profile_count sum =
> + dstbb->count.ipa () + srccount.ipa ();
> + if (sum.nonzero_p ())
> + 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 ());
looks good. You can use probability_in (sum)
in both of the places.
Honza
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v4] ipa-utils: avoid uninitialized probabilities on ICF [PR111559]
2023-10-05 13:04 ` Jan Hubicka
@ 2023-10-05 13:11 ` Sergei Trofimovich
2023-10-05 13:27 ` Jan Hubicka
0 siblings, 1 reply; 7+ messages in thread
From: Sergei Trofimovich @ 2023-10-05 13:11 UTC (permalink / raw)
To: Jan Hubicka; +Cc: gcc-patches, rguenther, siarheit
[-- Attachment #1: Type: text/plain, Size: 1356 bytes --]
On Thu, Oct 05, 2023 at 03:04:55PM +0200, Jan Hubicka wrote:
> > diff --git a/gcc/ipa-utils.cc b/gcc/ipa-utils.cc
> > index 956c6294fd7..1355ccac6f0 100644
> > --- a/gcc/ipa-utils.cc
> > +++ b/gcc/ipa-utils.cc
> > @@ -651,13 +651,16 @@ ipa_merge_profiles (struct cgraph_node *dst,
> > {
> > 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 ());
> > + profile_count sum =
> > + dstbb->count.ipa () + srccount.ipa ();
> > + if (sum.nonzero_p ())
> > + 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 ());
>
> looks good. You can use probability_in (sum)
> in both of the places.
Oh, great point! Completely forgot about it. Attached v4.
If it still looks reasonable I'll check again if `python` and
`profiledbootstrap` still survives it and will push.
--
Sergei
[-- Attachment #2: v4-0001-ipa-utils-avoid-uninitialized-probabilities-on-IC.patch --]
[-- Type: text/plain, Size: 3074 bytes --]
From cb9852216b5b2524f72964b399c133557ec98df0 Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <siarheit@google.com>
Date: Wed, 27 Sep 2023 14:29:12 +0100
Subject: [PATCH v4] 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.
---
gcc/ipa-utils.cc | 15 ++++++++-------
gcc/testsuite/gcc.dg/tree-prof/pr111559.c | 16 ++++++++++++++++
2 files changed, 24 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-prof/pr111559.c
diff --git a/gcc/ipa-utils.cc b/gcc/ipa-utils.cc
index 956c6294fd7..6024ac69cc2 100644
--- a/gcc/ipa-utils.cc
+++ b/gcc/ipa-utils.cc
@@ -651,13 +651,14 @@ ipa_merge_profiles (struct cgraph_node *dst,
{
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 ());
+ profile_count sum =
+ dstbb->count.ipa () + srccount.ipa ();
+ if (sum.nonzero_p ())
+ dste->probability =
+ dste->probability * dstbb->count.ipa ().probability_in
+ (sum)
+ + srce->probability * srcbb->count.ipa ().probability_in
+ (sum);
}
dstbb->count = dstbb->count.ipa () + srccount.ipa ();
}
diff --git a/gcc/testsuite/gcc.dg/tree-prof/pr111559.c b/gcc/testsuite/gcc.dg/tree-prof/pr111559.c
new file mode 100644
index 00000000000..43202c6c888
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-prof/pr111559.c
@@ -0,0 +1,16 @@
+/* { dg-options "-O2" } */
+
+__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();
+}
--
2.42.0
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v4] ipa-utils: avoid uninitialized probabilities on ICF [PR111559]
2023-10-05 13:11 ` [PATCH v4] " Sergei Trofimovich
@ 2023-10-05 13:27 ` Jan Hubicka
0 siblings, 0 replies; 7+ messages in thread
From: Jan Hubicka @ 2023-10-05 13:27 UTC (permalink / raw)
To: Sergei Trofimovich; +Cc: gcc-patches, rguenther, siarheit
> On Thu, Oct 05, 2023 at 03:04:55PM +0200, Jan Hubicka wrote:
> > > diff --git a/gcc/ipa-utils.cc b/gcc/ipa-utils.cc
> > > index 956c6294fd7..1355ccac6f0 100644
> > > --- a/gcc/ipa-utils.cc
> > > +++ b/gcc/ipa-utils.cc
> > > @@ -651,13 +651,16 @@ ipa_merge_profiles (struct cgraph_node *dst,
> > > {
> > > 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 ());
> > > + profile_count sum =
> > > + dstbb->count.ipa () + srccount.ipa ();
> > > + if (sum.nonzero_p ())
> > > + 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 ());
> >
> > looks good. You can use probability_in (sum)
> > in both of the places.
>
> Oh, great point! Completely forgot about it. Attached v4.
>
> If it still looks reasonable I'll check again if `python` and
> `profiledbootstrap` still survives it and will push.
Looks good, thanks!
Honza
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2023-10-05 13:27 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-09-27 14:44 [PATCH] ipa-utils: avoid generating uninitialized probabilities on merges Sergei Trofimovich
2023-10-01 19:29 ` [PATCH v2] ipa-utils: avoid uninitialized probabilities on ICF [PR111559] Sergei Trofimovich
2023-10-05 11:52 ` Jan Hubicka
2023-10-05 12:46 ` Sergei Trofimovich
2023-10-05 13:04 ` Jan Hubicka
2023-10-05 13:11 ` [PATCH v4] " Sergei Trofimovich
2023-10-05 13:27 ` Jan Hubicka
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).