procyberian/gcc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

predict.c (determine_unlikely_bbs): Forward declare...

Browse source 
* predict.c (determine_unlikely_bbs): Forward declare; also determine
	edges that are always known to be taken because it is only likely
	edge out of given BB.
	(tree_estimate_probability): Call before profile guessing to get bit
	of extra precision.

	* gcc.dg/predict-13.c: Update template.
	* gcc.dg/predict-13b.c: New testcase.
	* gcc.dg/predict-22.c: New testcase.
	* gcc.dg/tree-ssa/ipa-split-4.c: Change abort to other function to
	get sane profile.

From-SVN: r266587
This commit is contained in:
Jan Hubicka 2018-11-28 21:48:53 +01:00 • committed by Jan Hubicka
parent ad42aa96b6
commit 410902c31c
7 changed files with 142 additions and 14 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
gcc/ChangeLog
View file

@ -1,3 +1,11 @@
2018-11-28 Jan Hubicka <jh@suse.cz>
* predict.c (determine_unlikely_bbs): Forward declare; also determine
edges that are always known to be taken because it is only likely
edge out of given BB.
(tree_estimate_probability): Call before profile guessing to get bit
of extra precision.
2018-11-28 Jan Hubicka <jh@suse.cz>
* tree-ssa-ifcombine.c (update_profile_after_ifcombine): Handle

47
gcc/predict.c
View file

@ -93,6 +93,7 @@ static void predict_paths_leading_to_edge (edge, enum br_predictor,
struct loop *in_loop = NULL);
static bool can_predict_insn_p (const rtx_insn *);
static HOST_WIDE_INT get_predictor_value (br_predictor, HOST_WIDE_INT);
static void determine_unlikely_bbs ();
/* Information we hold about each branch predictor.
Filled using information from predict.def. */
@ -3063,6 +3064,9 @@ tree_estimate_probability (bool dry_run)
preheaders. */
create_preheaders (CP_SIMPLE_PREHEADERS);
calculate_dominance_info (CDI_POST_DOMINATORS);
/* Decide which edges are known to be unlikely. This improves later
branch prediction. */
determine_unlikely_bbs ();
bb_predictions = new hash_map<const_basic_block, edge_prediction *>;
tree_bb_level_predictions ();
@ -3768,17 +3772,40 @@ determine_unlikely_bbs ()
}
/* Finally all edges from non-0 regions to 0 are unlikely. */
FOR_ALL_BB_FN (bb, cfun)
if (!(bb->count == profile_count::zero ()))
{
if (!(bb->count == profile_count::zero ()))
FOR_EACH_EDGE (e, ei, bb->succs)
if (!(e->probability == profile_probability::never ())
&& e->dest->count == profile_count::zero ())
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Edge %i->%i is unlikely because "
"it enters unlikely block\n",
bb->index, e->dest->index);
e->probability = profile_probability::never ();
}
edge other = NULL;
FOR_EACH_EDGE (e, ei, bb->succs)
if (!(e->probability == profile_probability::never ())
&& e->dest->count == profile_count::zero ())
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Edge %i->%i is unlikely because "
"it enters unlikely block\n",
bb->index, e->dest->index);
e->probability = profile_probability::never ();
}
if (e->probability == profile_probability::never ())
;
else if (other)
{
other = NULL;
break;
}
else
other = e;
if (other
&& !(other->probability == profile_probability::always ()))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Edge %i->%i is locally likely\n",
bb->index, other->dest->index);
other->probability = profile_probability::always ();
}
}
if (ENTRY_BLOCK_PTR_FOR_FN (cfun)->count == profile_count::zero ())
cgraph_node::get (current_function_decl)->count = profile_count::zero ();
}

8
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,11 @@
2018-11-28 Jan Hubicka <jh@suse.cz>
* gcc.dg/predict-13.c: Update template.
* gcc.dg/predict-13b.c: New testcase.
* gcc.dg/predict-22.c: New testcase.
* gcc.dg/tree-ssa/ipa-split-4.c: Change abort to other function to
get sane profile.
2018-11-28 Marek Polacek <polacek@redhat.com>
PR c++/88222 - ICE with bit-field with invalid type.

4
gcc/testsuite/gcc.dg/predict-13.c
View file

@ -20,5 +20,5 @@ int main(int argc, char **argv)
return 10;
}
/* { dg-final { scan-tree-dump-times "combined heuristics of edge\[^:\]*: 33.30%" 3 "profile_estimate"} } */
/* { dg-final { scan-tree-dump-times "combined heuristics of edge\[^:\]*: 0.05%" 2 "profile_estimate"} } */
/* { dg-final { scan-tree-dump-times "33.33%" 3 "profile_estimate"} } */
/* { dg-final { scan-tree-dump-times "0.00%" 3 "profile_estimate"} } */

26
gcc/testsuite/gcc.dg/predict-13b.c Normal file
View file

@ -0,0 +1,26 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-profile_estimate" } */
void exit(int);
int main(int argc, char **argv)
{
switch (argc)
{
case 1:
return 1;
case 2:
return 2;
case 3:
exit(1);
case 4:
exit(2);
default:
return 5;
}
return 10;
}
/* { dg-final { scan-tree-dump-times "combined heuristics of edge\[^:\]*: 33.30%" 3 "profile_estimate"} } */
/* { dg-final { scan-tree-dump-times "combined heuristics of edge\[^:\]*: 0.05%" 2 "profile_estimate"} } */

59
gcc/testsuite/gcc.dg/predict-22.c Normal file
View file

@ -0,0 +1,59 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-optimized-details-blocks -fdump-rtl-bbpart-details-blocks -freorder-blocks-and-partition" } */
volatile int v;
void bar (void) __attribute__((leaf, cold));
void baz (int *);
void
foo (int x, int y, int z)
{
static int f __attribute__((section ("mysection")));
f = 1;
if (__builtin_expect (x, 0))
if (__builtin_expect (y, 0))
if (__builtin_expect (z, 0))
{
f = 2;
bar ();
v += 1;
v *= 2;
v /= 2;
v -= 1;
v += 1;
v *= 2;
v /= 2;
v -= 1;
v += 1;
v *= 2;
v /= 2;
v -= 1;
v += 1;
v *= 2;
v /= 2;
v -= 1;
v += 1;
v *= 2;
v /= 2;
v -= 1;
v += 1;
v *= 2;
v /= 2;
v -= 1;
v += 1;
v *= 2;
v /= 2;
v -= 1;
v += 1;
v *= 2;
v /= 2;
v -= 1;
f = 3;
__builtin_abort ();
}
f = 4;
f = 5;
baz (&f);
}
/* { dg-final { scan-tree-dump-times "Invalid sum" 0 "optimized"} } */
/* { dg-final { scan-tree-dump-times "count 0," 1 "optimized"} } */
/* { dg-final { scan-rtl-dump-times "COLD_PARTITION" 1 "bbpart"} } */

4
gcc/testsuite/gcc.dg/tree-ssa/ipa-split-4.c
View file

@ -1,14 +1,14 @@
/* { dg-do compile } */
/* { dg-options "-O3 -fdump-tree-fnsplit" } */
int make_me_big (void);
void abort (void);
void do_work (void);
int
split_me (int a)
{
if (__builtin_expect(a<10, 1))
{
abort ();
do_work ();
}
else
{