[05/77] Small tweak to array_value_type

[Richard Sandiford]

Store the type mode in a variable so that a later,
more mechanical patch can change its type.

2017-07-13  Richard Sandiford  <richard.sandif...@linaro.org>
            Alan Hayward  <alan.hayw...@arm.com>
            David Sherwood  <david.sherw...@arm.com>

gcc/
        * tree-switch-conversion.c (array_value_type): Only read TYPE_MODE
        once.  Use get_narrowest_mode instead of GET_CLASS_NARROWEST_MODE.

Index: gcc/tree-switch-conversion.c
===================================================================
--- gcc/tree-switch-conversion.c        2017-06-30 12:50:38.647644058 +0100
+++ gcc/tree-switch-conversion.c        2017-07-13 09:18:22.307345334 +0100
@@ -1034,7 +1034,6 @@ array_value_type (gswitch *swtch, tree t
 {
   unsigned int i, len = vec_safe_length (info->constructors[num]);
   constructor_elt *elt;
-  machine_mode mode;
   int sign = 0;
   tree smaller_type;
 
@@ -1048,8 +1047,9 @@ array_value_type (gswitch *swtch, tree t
   if (!INTEGRAL_TYPE_P (type))
     return type;
 
-  mode = GET_CLASS_NARROWEST_MODE (GET_MODE_CLASS (TYPE_MODE (type)));
-  if (GET_MODE_SIZE (TYPE_MODE (type)) <= GET_MODE_SIZE (mode))
+  machine_mode type_mode = TYPE_MODE (type);
+  machine_mode mode = get_narrowest_mode (type_mode);
+  if (GET_MODE_SIZE (type_mode) <= GET_MODE_SIZE (mode))
     return type;
 
   if (len < (optimize_bb_for_size_p (gimple_bb (swtch)) ? 2 : 32))
@@ -1087,7 +1087,7 @@ array_value_type (gswitch *swtch, tree t
 
          mode = GET_MODE_WIDER_MODE (mode);
          if (mode == VOIDmode
-             || GET_MODE_SIZE (mode) >= GET_MODE_SIZE (TYPE_MODE (type)))
+             || GET_MODE_SIZE (mode) >= GET_MODE_SIZE (type_mode))
            return type;
        }
     }