The following fixes another issue with updating of reduc_idx in pattern
sequences. But the testcase also shows the pattern in question is
harmful for vectorization since a reduction path may not contain
promotions/demotions. So the already existing but ineffective check
to guard the pattern is fixed.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
PR tree-optimization/122301
* tree-vect-patterns.cc (vect_recog_over_widening_pattern):
Fix reduction guard.
(vect_mark_pattern_stmts): Fix reduction def check.
* gcc.dg/vect/vect-pr122301.c: New testcase.
---
gcc/testsuite/gcc.dg/vect/vect-pr122301.c | 16 ++++++++++++++++
gcc/tree-vect-patterns.cc | 9 ++++++---
2 files changed, 22 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/vect/vect-pr122301.c
diff --git a/gcc/testsuite/gcc.dg/vect/vect-pr122301.c
b/gcc/testsuite/gcc.dg/vect/vect-pr122301.c
new file mode 100644
index 00000000000..acc7aedf190
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-pr122301.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+
+int get_prev_frame_segid(unsigned char *p, int n)
+{
+ int tem;
+ unsigned seg_id = 8;
+ for (int x = 0; x < n; x++)
+ {
+ int a = seg_id;
+ tem = a < p[x] ? a : p[x];
+ seg_id = tem;
+ }
+ return tem;
+}
+
+/* { dg-final { scan-tree-dump "optimized: loop vectorized" "vect" { target {
vect_int && { ! vect_no_int_min_max } } } } } */
diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc
index becee62a9f5..de752176aee 100644
--- a/gcc/tree-vect-patterns.cc
+++ b/gcc/tree-vect-patterns.cc
@@ -3001,7 +3001,7 @@ vect_recog_over_widening_pattern (vec_info *vinfo,
tree_code code = gimple_assign_rhs_code (last_stmt);
/* Punt for reductions where we don't handle the type conversions. */
- if (STMT_VINFO_DEF_TYPE (last_stmt_info) == vect_reduction_def)
+ if (vect_is_reduction (last_stmt_info))
return NULL;
/* Keep the first operand of a COND_EXPR as-is: only the other two
@@ -7188,14 +7188,17 @@ vect_mark_pattern_stmts (vec_info *vinfo,
break;
}
/* Try harder to find a mid-entry into an earlier pattern
- sequence. This means that the initial 'lookfor' was
+ sequence. Likewise an entry to a stmt skipping a conversion
+ on an input. This means that the initial 'lookfor' was
bogus. */
if (!found)
{
for (unsigned i = 0; i < op.num_ops; ++i)
if (TREE_CODE (op.ops[i]) == SSA_NAME)
if (auto def = vinfo->lookup_def (op.ops[i]))
- if (vect_is_reduction (def))
+ if (vect_is_reduction (def)
+ || (is_a <gphi *> (def->stmt)
+ && STMT_VINFO_REDUC_DEF (def) != NULL))
{
STMT_VINFO_REDUC_IDX (vinfo->lookup_stmt (s)) = i;
lookfor = gimple_get_lhs (s);
--
2.51.0
