[PATCH] tree-optimization/127195 - ICE with vect_create_constant_vectors

[Richard Biener]

With excess lanes present we miscount the number of copies of the
SLP elements which eventually results in ctor_seq stmts not being
emitted.

Bootstrapped and tested on x86_64-unknown-linux-gnu and
aarch64-linux-gnu, pushed.

        PR tree-optimization/127195
        * tree-vect-slp.cc (vect_create_constant_vectors):
        Properly compute number_of_copies, assert we end up
        on a vector boundary.

        * gcc.dg/vect/vect-pr127195.c: New testcase.
---
 gcc/testsuite/gcc.dg/vect/vect-pr127195.c | 21 +++++++++++++++++++++
 gcc/tree-vect-slp.cc                      |  4 +++-
 2 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.dg/vect/vect-pr127195.c

diff --git a/gcc/testsuite/gcc.dg/vect/vect-pr127195.c 
b/gcc/testsuite/gcc.dg/vect/vect-pr127195.c
new file mode 100644
index 00000000000..57da05e4837
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-pr127195.c
@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+
+typedef struct {
+  unsigned bold : 1;
+  unsigned : 16;
+} vbi_char;
+typedef struct {
+  vbi_char text[];
+} vbi_page;
+vbi_page enhance_pg;
+vbi_char *enhance_acp = &enhance_pg.text[1];
+int enhance_col, enhance_column;
+void enhance()
+{
+  for (;;) {
+    int bold;
+    enhance_col = enhance_column;
+    for (; enhance_col; enhance_col++)
+      enhance_acp[enhance_col].bold = bold;
+  }
+}
diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 3e1bfd000f1..665a433a48f 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -10978,7 +10978,7 @@ vect_create_constant_vectors (vec_info *vinfo, slp_tree 
op_node)
   if (!TYPE_VECTOR_SUBPARTS (vector_type).is_constant (&nunits))
     nunits = group_size;
 
-  number_of_copies = nunits * number_of_vectors / group_size;
+  number_of_copies = (nunits * number_of_vectors - excess_elts) / group_size;
 
   constant_p = true;
   tree uniform_elt = NULL_TREE;
@@ -11130,6 +11130,8 @@ vect_create_constant_vectors (vec_info *vinfo, slp_tree 
op_node)
         }
     }
 
+  gcc_assert (number_of_places_left_in_vector == nunits);
+
   /* Since the vectors are created in the reverse order, we should invert
      them.  */
   vec_num = voprnds.length ();
-- 
2.51.0