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Fix clustering algorithm in switch expansion.

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2018-06-28  Martin Liska  <mliska@suse.cz>

	* tree-switch-conversion.c (jump_table_cluster::find_jump_tables):
        Add new checking assert to catch invalid state.
	(jump_table_cluster::can_be_handled): Handle single case
        clusters.
	(jump_table_cluster::is_beneficial): Bail out for such case.
	(bit_test_cluster::find_bit_tests):
        Add new checking assert to catch invalid state.
	(bit_test_cluster::can_be_handled): Handle single case
        clusters.
	(bit_test_cluster::is_beneficial): Bail out for such case.
	(switch_decision_tree::analyze_switch_statement):
        Fix comment.
2018-06-28  Martin Liska  <mliska@suse.cz>

	* gcc.dg/tree-ssa/switch-1.c: New test.

From-SVN: r262211
This commit is contained in:
Martin Liska 2018-06-28 09:14:57 +02:00 • committed by Martin Liska
parent d86c7648fb
commit df7c79742a
4 changed files with 154 additions and 2 deletions
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15
gcc/ChangeLog
View file

@ -1,3 +1,18 @@
2018-06-28 Martin Liska <mliska@suse.cz>
* tree-switch-conversion.c (jump_table_cluster::find_jump_tables):
Add new checking assert to catch invalid state.
(jump_table_cluster::can_be_handled): Handle single case
clusters.
(jump_table_cluster::is_beneficial): Bail out for such case.
(bit_test_cluster::find_bit_tests):
Add new checking assert to catch invalid state.
(bit_test_cluster::can_be_handled): Handle single case
clusters.
(bit_test_cluster::is_beneficial): Bail out for such case.
(switch_decision_tree::analyze_switch_statement):
Fix comment.
2018-06-28 Martin Liska <mliska@suse.cz>
* common.opt: Introduce -completion option.

4
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,7 @@
2018-06-28 Martin Liska <mliska@suse.cz>
* gcc.dg/tree-ssa/switch-1.c: New test.
2018-06-28 Eric Botcazou <ebotcazou@adacore.com>
* gnat.dg/debug15.adb: New test.

110
gcc/testsuite/gcc.dg/tree-ssa/switch-1.c Normal file
View file

@ -0,0 +1,110 @@
/* { dg-do compile { target { { x86_64-*-* aarch64-*-* ia64-*-* powerpc64-*-* } && lp64 } } } */
/* { dg-options "-O2 -fdump-tree-switchlower1 --param case-values-threshold=4" } */
int global;
int foo (int x)
{
switch (x) {
case 0:
case 10:
case 1000:
case 1010:
case 1025 ... 1030:
return 1;
default:
return 0;
}
}
/* { dg-final { scan-tree-dump ";; GIMPLE switch case clusters: 0 10 BT:1000-1030" "switchlower1" } } */
int foo2 (int x)
{
switch (x) {
case -100:
case 100:
case 1000:
case 10000:
case 100000:
return 1;
default:
return 0;
}
}
/* { dg-final { scan-tree-dump ";; GIMPLE switch case clusters: -100 100 1000 10000 100000" "switchlower1" } } */
int foo3 (int x)
{
switch (x) {
case 0:
case 10:
case 20:
global += 1;
return 3;
case 30:
case 33 ... 55:
case 57:
return 4;
case 60 ... 62:
return 1;
default:
return 0;
}
}
/* { dg-final { scan-tree-dump ";; GIMPLE switch case clusters: JT:0-62" "switchlower1" } } */
int foo4 (int x)
{
switch (x) {
case -100:
case 10:
case 20:
global += 1;
return 3;
case 30:
case 33 ... 55:
case 57:
return 4;
case 60 ... 62:
return 1;
case 600 ... 700:
return 12;
default:
return 0;
}
}
/* { dg-final { scan-tree-dump ";; GIMPLE switch case clusters: -100 JT:10-62 600-700" "switchlower1" } } */
int foo5 (int x)
{
switch (x) {
case 10:
case 20:
global += 1;
return 3;
case 30:
case 33 ... 55:
case 57:
return 4;
case 60 ... 62:
return 1;
case 600 ... 700:
return 12;
case 1000 ... 1010:
case 1012:
return 333;
case 1019:
case 1021:
return 9;
case 111111:
return 3;
default:
return 0;
}
}
/* { dg-final { scan-tree-dump ";; GIMPLE switch case clusters: JT:10-62 600-700 JT:1000-1021 111111" "switchlower1" } } */

27
gcc/tree-switch-conversion.c
View file

@ -1121,6 +1121,8 @@ jump_table_cluster::find_jump_tables (vec<cluster *> &clusters)
&& can_be_handled (clusters, j, i - 1))
min[i] = min_cluster_item (min[j].m_count + 1, j, s);
}
gcc_checking_assert (min[i].m_count != INT_MAX);
}
/* No result. */
@ -1172,8 +1174,13 @@ jump_table_cluster::can_be_handled (const vec<cluster *> &clusters,
if (!flag_jump_tables)
return false;
unsigned HOST_WIDE_INT max_ratio = optimize_insn_for_size_p () ? 3 : 8;
/* For algorithm correctness, jump table for a single case must return
true. We bail out in is_beneficial if it's called just for
a single case. */
if (start == end)
return true;
unsigned HOST_WIDE_INT max_ratio = optimize_insn_for_size_p () ? 3 : 8;
unsigned HOST_WIDE_INT range = get_range (clusters[start]->get_low (),
clusters[end]->get_high ());
/* Check overflow. */
@ -1197,6 +1204,10 @@ bool
jump_table_cluster::is_beneficial (const vec<cluster *> &,
unsigned start, unsigned end)
{
/* Single case bail out. */
if (start == end)
return false;
return end - start + 1 >= case_values_threshold ();
}
@ -1226,6 +1237,8 @@ bit_test_cluster::find_bit_tests (vec<cluster *> &clusters)
&& can_be_handled (clusters, j, i - 1))
min[i] = min_cluster_item (min[j].m_count + 1, j, INT_MAX);
}
gcc_checking_assert (min[i].m_count != INT_MAX);
}
/* No result. */
@ -1277,6 +1290,12 @@ bool
bit_test_cluster::can_be_handled (const vec<cluster *> &clusters,
unsigned start, unsigned end)
{
/* For algorithm correctness, bit test for a single case must return
true. We bail out in is_beneficial if it's called just for
a single case. */
if (start == end)
return true;
unsigned HOST_WIDE_INT range = get_range (clusters[start]->get_low (),
clusters[end]->get_high ());
auto_bitmap dest_bbs;
@ -1308,6 +1327,10 @@ bool
bit_test_cluster::is_beneficial (const vec<cluster *> &clusters,
unsigned start, unsigned end)
{
/* Single case bail out. */
if (start == end)
return false;
auto_bitmap dest_bbs;
for (unsigned i = start; i <= end; i++)
@ -1599,7 +1622,7 @@ switch_decision_tree::analyze_switch_statement ()
/* Find jump table clusters. */
vec<cluster *> output = jump_table_cluster::find_jump_tables (clusters);
/* Find jump table clusters. */
/* Find bit test clusters. */
vec<cluster *> output2;
auto_vec<cluster *> tmp;
output2.create (1);