[PATCH] tree-optimization/98685 - fix placement of extern converts

[PATCH] tree-optimization/98685 - fix placement of extern converts

[Richard Biener]

Avoid advancing to the next stmt when inserting at region boundary
and deal with a vector def being not the only child.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

2021-01-15  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/98685
	* tree-vect-slp.c (vect_schedule_slp_node): Refactor handling
	of vector extern defs.

	* gcc.dg/vect/bb-slp-pr98685.c: New testcase.
---
 gcc/testsuite/gcc.dg/vect/bb-slp-pr98685.c | 15 +++++++++++++++
 gcc/tree-vect-slp.c                        | 11 ++++++++---
 2 files changed, 23 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/vect/bb-slp-pr98685.c

diff --git a/gcc/testsuite/gcc.dg/vect/bb-slp-pr98685.c b/gcc/testsuite/gcc.dg/vect/bb-slp-pr98685.c
new file mode 100644
index 00000000000..b213335da78
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/bb-slp-pr98685.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-O3" } */
+
+char onelock_lock[16];
+void write(void);
+
+void lockit(int count) {
+  for (; count;) {
+    int pid, i;
+    char *p;
+    for (i = 0, p = (char *)&pid; i < sizeof 0; i++)
+      onelock_lock[i] = *p++;
+    write();
+  }
+}
diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index 6b6c9ccc0a0..1787ad74268 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -5915,6 +5915,7 @@ vect_schedule_slp_node (vec_info *vinfo,
       /* Emit other stmts after the children vectorized defs which is
 	 earliest possible.  */
       gimple *last_stmt = NULL;
+      bool seen_vector_def = false;
       FOR_EACH_VEC_ELT (SLP_TREE_CHILDREN (node), i, child)
 	if (SLP_TREE_DEF_TYPE (child) == vect_internal_def)
 	  {
@@ -5966,8 +5967,7 @@ vect_schedule_slp_node (vec_info *vinfo,
 	       we do not insert before the region boundary.  */
 	    if (SLP_TREE_SCALAR_OPS (child).is_empty ()
 		&& !vinfo->lookup_def (SLP_TREE_VEC_DEFS (child)[0]))
-	      last_stmt = gsi_stmt (gsi_after_labels
-				      (as_a <bb_vec_info> (vinfo)->bbs[0]));
+	      seen_vector_def = true;
 	    else
 	      {
 		unsigned j;
@@ -5987,7 +5987,12 @@ vect_schedule_slp_node (vec_info *vinfo,
 	 constants.  */
       if (!last_stmt)
 	last_stmt = vect_find_first_scalar_stmt_in_slp (node)->stmt;
-      if (is_a <gphi *> (last_stmt))
+      if (!last_stmt)
+	{
+	  gcc_assert (seen_vector_def);
+	  si = gsi_after_labels (as_a <bb_vec_info> (vinfo)->bbs[0]);
+	}
+      else if (is_a <gphi *> (last_stmt))
 	si = gsi_after_labels (gimple_bb (last_stmt));
       else
 	{
-- 
2.26.2