[PATCH] fix ICE with BB vectorization of PHIs

[Richard Biener]

This fixes a vector CTOR insertion issue when we try to insert after
a PHI node.

Bootstrap / regtest running on x86_64-unknown-linux-gnu.

2020-10-09  Richard Biener  <rguent...@suse.de>

        * tree-vect-slp.c (vect_create_constant_vectors): Properly insert
        after PHIs.

        * gcc.dg/vect/bb-slp-phis-1.c: New testcase.
---
 gcc/testsuite/gcc.dg/vect/bb-slp-phis-1.c | 20 ++++++++++++++++++++
 gcc/tree-vect-slp.c                       |  4 +++-
 2 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.dg/vect/bb-slp-phis-1.c

diff --git a/gcc/testsuite/gcc.dg/vect/bb-slp-phis-1.c 
b/gcc/testsuite/gcc.dg/vect/bb-slp-phis-1.c
new file mode 100644
index 00000000000..014c13b8506
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/bb-slp-phis-1.c
@@ -0,0 +1,20 @@
+/* From gcc.c-torture/execute/loop-13.c  */
+/* { dg-do compile } */
+/* { dg-additional-options "-march=cascadelake" { target x86_64-*-* i?86-*-* } 
} */
+#define TYPE long
+
+void
+scale (TYPE *alpha, TYPE *x, int n)
+{
+  int i, ix;
+
+  if (*alpha != 1)
+    for (i = 0, ix = 0; i < n; i++, ix += 2)
+      {
+       TYPE tmpr, tmpi;
+       tmpr = *alpha * x[ix];
+       tmpi = *alpha * x[ix + 1];
+       x[ix] = tmpr;
+       x[ix + 1] = tmpi;
+      }
+}
diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index 736d036f933..9f1eca734ab 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -4374,7 +4374,9 @@ vect_create_constant_vectors (vec_info *vinfo, slp_tree 
op_node)
                  if (insert_after)
                    {
                      gimple_stmt_iterator gsi;
-                     if (!stmt_ends_bb_p (insert_after->stmt))
+                     if (gimple_code (insert_after->stmt) == GIMPLE_PHI)
+                       gsi = gsi_after_labels (gimple_bb (insert_after->stmt));
+                     else if (!stmt_ends_bb_p (insert_after->stmt))
                        gsi = gsi_for_stmt (insert_after->stmt);
                      else
                        {
-- 
2.26.2