tree-ssa: Fix ICE in build_vector_type [PR93780]

The following testcase ICEs, because execute_update_addresses_taken attempts
to create a VECTOR_TYPE with non-power of 2 number of elts.
Fixed by guarding it with the corresponding predicate.

2020-02-18  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/93780
	* tree-ssa.c (non_rewritable_lvalue_p): Check valid_vector_subparts_p
	before calling build_vector_type.
	(execute_update_addresses_taken): Likewise.

	* gcc.dg/pr93780.c: New test.

gcc/ChangeLog

 2020-02-18  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/93780
+	* tree-ssa.c (non_rewritable_lvalue_p): Check valid_vector_subparts_p
+	before calling build_vector_type.
+	(execute_update_addresses_taken): Likewise.
+
 	PR driver/93796
 	* params.opt (-param=ipa-max-switch-predicate-bounds=): Fix help
 	typo, functoin -> function.

gcc/testsuite/ChangeLog

+2020-02-18  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/93780
+	* gcc.dg/pr93780.c: New test.
+
 2020-02-17  David Malcolm  <dmalcolm@redhat.com>
 
 	PR analyzer/93775
 	* gcc.dg/analyzer/20020129-1.c: New test.
 
-2020-02-17  Alexandre Oliva <oliva@adacore.com>
+2020-02-17  Alexandre Oliva  <oliva@adacore.com>
 
 	* gcc.dg/tls/emutls-3.c: New, combining emutls-2.c and
 	thr-init-2.c into an execution test with explicitly common

gcc/testsuite/gcc.dg/pr93780.c

+/* PR tree-optimization/93780 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+/* { dg-additional-options "-mavx" { target avx } } */
+
+typedef float V __attribute__((vector_size (32)));
+
+float
+foo (void)
+{
+  const float init[6] = {};
+  V v = {};
+  __builtin_memcpy (&v, init, sizeof (init));
+  return v[0];
+}

gcc/tree-ssa.c

@@ -1550,7 +1550,8 @@ non_rewritable_lvalue_p (tree lhs)
 	      && multiple_p (lhs_bits,
 			     tree_to_uhwi
 			       (TYPE_SIZE (TREE_TYPE (TREE_TYPE (decl)))),
-			     &nelts))
+			     &nelts)
+	      && valid_vector_subparts_p (nelts))
 	    {
 	      if (known_eq (nelts, 1u))
 		return false;
@@ -1925,7 +1926,8 @@ execute_update_addresses_taken (void)
 					     (TYPE_SIZE (TREE_TYPE
 							   (TREE_TYPE (sym)))),
 					   &nelts)
-			    && maybe_ne (nelts, 1u))
+			    && maybe_ne (nelts, 1u)
+			    && valid_vector_subparts_p (nelts))
 			  temtype = build_vector_type (temtype, nelts);
 			tree tem = make_ssa_name (temtype);
 			gimple *pun