[11/67] Add a float_mode_for_size helper function

diff --git a/gcc/coretypes.h b/gcc/coretypes.h
index f4c1859..8341cab 100644
--- a/gcc/coretypes.h
+++ b/gcc/coretypes.h
@@ -58,6 +58,7 @@  typedef const struct rtx_def *const_rtx;
 class machine_mode;
 class scalar_float_mode;
 template<typename> class opt_mode;
+typedef opt_mode<scalar_float_mode> opt_scalar_float_mode;
 
 /* Subclasses of rtx_def, using indentation to show the class
    hierarchy, along with the relevant invariant.
diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c
index 3bcafbb..efddad4 100644
--- a/gcc/emit-rtl.c
+++ b/gcc/emit-rtl.c
@@ -71,7 +71,6 @@  struct target_rtl *this_target_rtl = &default_target_rtl;
 
 machine_mode byte_mode;	/* Mode whose width is BITS_PER_UNIT.  */
 machine_mode word_mode;	/* Mode whose width is BITS_PER_WORD.  */
-machine_mode double_mode;	/* Mode whose width is DOUBLE_TYPE_SIZE.  */
 machine_mode ptr_mode;	/* Mode whose width is POINTER_SIZE.  */
 
 /* Datastructures maintained for currently processed function in RTL form.  */
@@ -5864,7 +5863,7 @@  init_emit_once (void)
 {
   int i;
   machine_mode mode;
-  machine_mode double_mode;
+  scalar_float_mode double_mode;
 
   /* Initialize the CONST_INT, CONST_WIDE_INT, CONST_DOUBLE,
      CONST_FIXED, and memory attribute hash tables.  */
@@ -5908,7 +5907,7 @@  init_emit_once (void)
   else
     const_true_rtx = gen_rtx_CONST_INT (VOIDmode, STORE_FLAG_VALUE);
 
-  double_mode = mode_for_size (DOUBLE_TYPE_SIZE, MODE_FLOAT, 0);
+  double_mode = *float_mode_for_size (DOUBLE_TYPE_SIZE);
 
   real_from_integer (&dconst0, double_mode, 0, SIGNED);
   real_from_integer (&dconst1, double_mode, 1, SIGNED);
diff --git a/gcc/machmode.h b/gcc/machmode.h
index 996f991..41a3a00 100644
--- a/gcc/machmode.h
+++ b/gcc/machmode.h
@@ -513,7 +513,16 @@  extern const unsigned char mode_complex[NUM_MACHINE_MODES];
 
 extern machine_mode mode_for_size (unsigned int, enum mode_class, int);
 
-/* Similar, but find the smallest mode for a given width.  */
+/* Return the machine mode to use for a MODE_FLOAT of SIZE bits, if one
+   exists.  */
+
+inline opt_scalar_float_mode
+float_mode_for_size (unsigned int size)
+{
+  return dyn_cast <scalar_float_mode> (mode_for_size (size, MODE_FLOAT, 0));
+}
+
+/* Similar to mode_for_size, but find the smallest mode for a given width.  */
 
 extern machine_mode smallest_mode_for_size (unsigned int,
 						 enum mode_class);
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 834cf8b..2cde94e 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -2132,14 +2132,16 @@  layout_type (tree type)
       break;
 
     case REAL_TYPE:
-      /* Allow the caller to choose the type mode, which is how decimal
-	 floats are distinguished from binary ones.  */
-      if (TYPE_MODE (type) == VOIDmode)
-	SET_TYPE_MODE (type,
-		       mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0));
-      TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
-      TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
-      break;
+      {
+	/* Allow the caller to choose the type mode, which is how decimal
+	   floats are distinguished from binary ones.  */
+	if (TYPE_MODE (type) == VOIDmode)
+	  SET_TYPE_MODE (type, *float_mode_for_size (TYPE_PRECISION (type)));
+	scalar_float_mode mode = as_a <scalar_float_mode> (TYPE_MODE (type));
+	TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (mode));
+	TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (mode));
+	break;
+      }
 
    case FIXED_POINT_TYPE:
      /* TYPE_MODE (type) has been set already.  */