When a basic block A has been annotated with a count and it has only one
successor (or predecessor) B, we can propagate the A's count to B.
The algorithm without this change could leave B without an annotation if B had
other unannotated predecessors (or successors). For example, in the test case I
added,
the loop header block was left unannotated, which prevented loop unrolling.
gcc/ChangeLog:
* auto-profile.c (afdo_propagate_edge): Improve count propagation
algorithm.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-prof/init-array.c: New test for unrolling inner loops.
---
gcc/auto-profile.c | 20 +++++++++-
gcc/testsuite/gcc.dg/tree-prof/init-array.c | 43 +++++++++++++++++++++
2 files changed, 61 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-prof/init-array.c
diff --git a/gcc/auto-profile.c b/gcc/auto-profile.c
index 4c1fc6b536b..dfcd68113aa 100644
--- a/gcc/auto-profile.c
+++ b/gcc/auto-profile.c
@@ -1192,7 +1192,8 @@ afdo_find_equiv_class (bb_set *annotated_bb)
/* If a basic block's count is known, and only one of its in/out edges' count
is unknown, its count can be calculated. Meanwhile, if all of the in/out
edges' counts are known, then the basic block's unknown count can also be
- calculated.
+ calculated. Also, if a block has a single predecessor or successor, the
block's
+ count can be propagated to that predecessor or successor.
IS_SUCC is true if out edges of a basic blocks are examined.
Update ANNOTATED_BB accordingly.
Return TRUE if any basic block/edge count is changed. */
@@ -1208,6 +1209,7 @@ afdo_propagate_edge (bool is_succ, bb_set *annotated_bb)
edge e, unknown_edge = NULL;
edge_iterator ei;
int num_unknown_edge = 0;
+ int num_edge = 0;
profile_count total_known_count = profile_count::zero ().afdo ();
FOR_EACH_EDGE (e, ei, is_succ ? bb->succs : bb->preds)
@@ -1217,6 +1219,7 @@ afdo_propagate_edge (bool is_succ, bb_set *annotated_bb)
num_unknown_edge++, unknown_edge = e;
else
total_known_count += AFDO_EINFO (e)->get_count ();
+ num_edge++;
}
/* Be careful not to annotate block with no successor in special cases. */
@@ -1230,7 +1233,20 @@ afdo_propagate_edge (bool is_succ, bb_set *annotated_bb)
else if (num_unknown_edge == 1 && is_bb_annotated (bb, *annotated_bb))
{
if (bb->count > total_known_count)
- AFDO_EINFO (unknown_edge)->set_count (bb->count - total_known_count);
+ {
+ profile_count new_count = bb->count - total_known_count;
+ AFDO_EINFO(unknown_edge)->set_count(new_count);
+ if (num_edge == 1)
+ {
+ basic_block succ_or_pred_bb = is_succ ? unknown_edge->dest :
unknown_edge->src;
+ if (new_count > succ_or_pred_bb->count)
+ {
+ succ_or_pred_bb->count = new_count;
+ if (!is_bb_annotated (succ_or_pred_bb, *annotated_bb))
+ set_bb_annotated (succ_or_pred_bb, annotated_bb);
+ }
+ }
+ }
else
AFDO_EINFO (unknown_edge)->set_count (profile_count::zero().afdo ());
AFDO_EINFO (unknown_edge)->set_annotated ();
diff --git a/gcc/testsuite/gcc.dg/tree-prof/init-array.c
b/gcc/testsuite/gcc.dg/tree-prof/init-array.c
new file mode 100644
index 00000000000..0f7a5c84481
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-prof/init-array.c
@@ -0,0 +1,43 @@
+/* { dg-options "-O3 -fdump-tree-cunrolli-details" } */
+
+static int s[10][10][10];
+static int d[10][10][10];
+
+__attribute__((noipa))
+int array()
+{
+ int i;
+ register int j, k;
+ for (i = 0; i < 10; i++)
+ for (j = 0; j < 10; j++)
+ for (k = 0; k < 10; k++)
+ d[i][j][k] = s[i][j][k];
+
+ return(0);
+}
+
+__attribute__((noipa))
+void TestBench()
+{
+ for (int i = 0; i < 150000; ++i)
+ {
+ array();
+ }
+}
+
+int main(int argc, char *argv[])
+{
+
+ TestBench();
+
+ if (d[9][9][9] == 0 && s[9][9][9] == 0)
+ {
+ return 0;
+ }
+ else
+ {
+ return -1;
+ }
+}
+
+/* { dg-final-use { scan-tree-dump-times "loop with 10 iterations completely
unrolled" 2 "cunrolli"} } */
--
2.25.1
