tree-optimization/101615 - SLP permute opt with CTOR roots

CTOR roots are not explicitely represented so we have to make sure
to materialize permutes on SLP graph entries to them.

2021-07-28  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/101615
	* tree-vect-slp.c (vect_optimize_slp): Materialize permutes
	at CTOR SLP graph entries.

	* gcc.dg/vect/bb-slp-pr101615-2.c: New testcase.

2 files changed, 35 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.dg/vect/bb-slp-pr101615-2.c b/gcc/testsuite/gcc.dg/vect/bb-slp-pr101615-2.c
new file mode 100644
index 0000000..ac89883
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/bb-slp-pr101615-2.c
@@ -0,0 +1,23 @@
+/* { dg-do run } */
+/* { dg-additional-options "-O3 -w -Wno-psabi" } */
+
+#include "tree-vect.h"
+
+int res[6] = { 5, 7, 11, 3, 3, 3 };
+int a[6] = {5, 5, 8};
+int c;
+
+int main()
+{
+  check_vect ();
+  for (int b = 0; b <= 4; b++)
+    for (; c <= 4; c++) {
+	a[0] |= 1;
+	for (int e = 0; e <= 4; e++)
+	  a[e + 1] |= 3;
+    }
+  for (int d = 0; d < 6; d++)
+    if (a[d] != res[d])
+      __builtin_abort ();
+  return 0;
+}
diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index 07cc24a..a554c24 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -3715,6 +3715,18 @@ vect_optimize_slp (vec_info *vinfo)
       vertices[idx].perm_out = perms.length () - 1;
     }
 
+  /* In addition to the above we have to mark outgoing permutes facing
+     non-reduction graph entries that are not represented as to be
+     materialized.  */
+  for (slp_instance instance : vinfo->slp_instances)
+    if (SLP_INSTANCE_KIND (instance) == slp_inst_kind_ctor)
+      {
+	/* Just setting perm_out isn't enough for the propagation to
+	   pick this up.  */
+	vertices[SLP_INSTANCE_TREE (instance)->vertex].perm_in = 0;
+	vertices[SLP_INSTANCE_TREE (instance)->vertex].perm_out = 0;
+      }
+
   /* Propagate permutes along the graph and compute materialization points.  */
   bool changed;
   bool do_materialization = false;