tree-optimization/112505 - bit-precision induction vectorization

Vectorization of bit-precision inductions isn't implemented but we
don't check this, instead we ICE during transform.

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

	PR tree-optimization/112505
	* tree-vect-loop.cc (vectorizable_induction): Reject
	bit-precision induction.

	* gcc.dg/vect/pr112505.c: New testcase.

gcc/testsuite/gcc.dg/vect/pr112505.c

@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-O3" } */
+
+short int w9;
+struct T {
+  short a : 14;
+  int b;
+};
+struct T v;
+void zc()
+{
+  for(int i = 0; i < 4; i ++)
+    w9 *= v.b ? v.a-- < 0 : 0;
+}

gcc/tree-vect-loop.cc

@@ -9273,6 +9273,15 @@ vectorizable_induction (loop_vec_info loop_vinfo,
 
   step_expr = STMT_VINFO_LOOP_PHI_EVOLUTION_PART (stmt_info);
   gcc_assert (step_expr != NULL_TREE);
+  if (INTEGRAL_TYPE_P (TREE_TYPE (step_expr))
+      && !type_has_mode_precision_p (TREE_TYPE (step_expr)))
+    {
+      if (dump_enabled_p ())
+	dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+			 "bit-precision induction vectorization not "
+			 "supported.\n");
+      return false;
+    }
   tree step_vectype = get_same_sized_vectype (TREE_TYPE (step_expr), vectype);
 
   /* Check for backend support of PLUS/MINUS_EXPR. */