The reported regression of libgomp loop-14.C shows that there isn't
generally a good reliable place to insert the permute upfront so
the following simply restricts recurrence vectorization to the cases
where the latch value isn't defined by a PHI.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
* tree-vect-loop.cc (vect_phi_first_order_recurrence_p):
Disallow latch PHI defs.
(vectorizable_recurr): Revert previous change.
---
gcc/tree-vect-loop.cc | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 92790bd8095..d5c2bff80be 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -543,6 +543,7 @@ vect_phi_first_order_recurrence_p (loop_vec_info
loop_vinfo, class loop *loop,
tree ldef = PHI_ARG_DEF_FROM_EDGE (phi, latch);
if (TREE_CODE (ldef) != SSA_NAME
|| SSA_NAME_IS_DEFAULT_DEF (ldef)
+ || is_a <gphi *> (SSA_NAME_DEF_STMT (ldef))
|| !flow_bb_inside_loop_p (loop, gimple_bb (SSA_NAME_DEF_STMT (ldef))))
return false;
@@ -8486,14 +8487,8 @@ vectorizable_recurr (loop_vec_info loop_vinfo,
stmt_vec_info stmt_info,
vectorized the latch definition. */
edge le = loop_latch_edge (LOOP_VINFO_LOOP (loop_vinfo));
gimple *latch_def = SSA_NAME_DEF_STMT (PHI_ARG_DEF_FROM_EDGE (phi, le));
- gimple_stmt_iterator gsi2;
- if (is_a <gphi *> (latch_def))
- gsi2 = gsi_after_labels (gimple_bb (latch_def));
- else
- {
- gsi2 = gsi_for_stmt (latch_def);
- gsi_next (&gsi2);
- }
+ gimple_stmt_iterator gsi2 = gsi_for_stmt (latch_def);
+ gsi_next (&gsi2);
for (unsigned i = 0; i < ncopies; ++i)
{
--
2.35.3
