On 08/06/15 17:55, Thomas Schwinge wrote:
Hi Tom!
On Mon, 8 Jun 2015 12:43:01 +0200, Tom de Vries <tom_devr...@mentor.com> wrote:
There are two problems in try_transform_to_exit_first_loop_alt:
1. In case the latch is not a singleton bb, the function should return
false rather than true.
2. The check for singleton bb should ignore debug-insns.
Attached patch fixes these problems.
Fix try_transform_to_exit_first_loop_alt
PR tree-optimization/66442
* gimple-iterator.h (gimple_seq_nondebug_singleton_p): Add function.
* tree-parloops.c (try_transform_to_exit_first_loop_alt): Return false
if the loop latch is not a singleton. Use
gimple_seq_nondebug_singleton_p instead of gimple_seq_singleton_p.
Per my testing, the backport of this patch that you committed to
gomp-4_0-branch, r224219, introduces a number of regressions in your
OpenACC kernels test cases, specifically the »scan-tree-dump-times
parloops_oacc_kernels "(?n)pragma omp target
oacc_parallel.*num_gangs\\(32\\)" 1« tests. Would you please have a
look?
Hi Thomas,
I seem to have committed (to both trunk and gomp-4_0-branch) an older
version of the patch, which contained an incorrect version of
gimple_seq_nondebug_singleton_p.
I'll correct the mistake tomorrow morning.
Thanks,
- Tom
Grüße,
Thomas
gcc/gimple-iterator.h | 29 +++++++++++++++++++++++++++++
gcc/tree-parloops.c | 4 ++--
2 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/gcc/gimple-iterator.h b/gcc/gimple-iterator.h
index 87e943a..76fa456 100644
--- a/gcc/gimple-iterator.h
+++ b/gcc/gimple-iterator.h
@@ -345,4 +345,33 @@ gsi_seq (gimple_stmt_iterator i)
return *i.seq;
}
+/* Determine whether SEQ is a nondebug singleton. */
+
+static inline bool
+gimple_seq_nondebug_singleton_p (gimple_seq seq)
+{
+ gimple_stmt_iterator gsi;
+
+ /* Find a nondebug gimple. */
+ gsi.ptr = gimple_seq_first (seq);
+ gsi.seq = &seq;
+ gsi.bb = NULL;
+ while (!gsi_end_p (gsi)
+ && is_gimple_debug (gsi_stmt (gsi)))
+ gsi_next (&gsi);
+
+ /* No nondebug gimple found, not a singleton. */
+ if (gsi_end_p (gsi))
+ return false;
+
+ /* Find a next nondebug gimple. */
+ gsi_next (&gsi);
+ while (!gsi_end_p (gsi)
+ && is_gimple_debug (gsi_stmt (gsi)))
+ gsi_next (&gsi);
+
+ /* Only a singleton if there's no next nondebug gimple. */
+ return gsi_end_p (gsi);
+}
+
#endif /* GCC_GIMPLE_ITERATOR_H */
diff --git a/gcc/tree-parloops.c b/gcc/tree-parloops.c
index 02f44eb..c4b83fe 100644
--- a/gcc/tree-parloops.c
+++ b/gcc/tree-parloops.c
@@ -1769,8 +1769,8 @@ try_transform_to_exit_first_loop_alt (struct loop *loop,
tree nit)
{
/* Check whether the latch contains a single statement. */
- if (!gimple_seq_singleton_p (bb_seq (loop->latch)))
- return true;
+ if (!gimple_seq_nondebug_singleton_p (bb_seq (loop->latch)))
+ return false;
/* Check whether the latch contains the loop iv increment. */
edge back = single_succ_edge (loop->latch);
--
1.9.1
