[74/77] Various small scalar_mode changes

This patch uses scalar_mode in a few miscellaneous places:

- Previous patches mean mode_to_vector can take a scalar_mode without
  further changes.

- Implicit promotion is limited to scalar types (affects promote_mode
  and sdbout_parms)

2017-08-30  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* machmode.h (mode_for_vector): Take a scalar_mode instead
	of a machine_mode.
	* stor-layout.c (mode_for_vector): Likewise.
	* explow.c (promote_mode): Use as_a <scalar_mode>.
	* sdbout.c (sdbout_parms): Use is_a <scalar_mode>.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r251525

gcc/ChangeLog

@@ -2,6 +2,16 @@
 	    Alan Hayward  <alan.hayward@arm.com>
 	    David Sherwood  <david.sherwood@arm.com>
 
+	* machmode.h (mode_for_vector): Take a scalar_mode instead
+	of a machine_mode.
+	* stor-layout.c (mode_for_vector): Likewise.
+	* explow.c (promote_mode): Use as_a <scalar_mode>.
+	* sdbout.c (sdbout_parms): Use is_a <scalar_mode>.
+
+2017-08-30  Richard Sandiford  <richard.sandiford@linaro.org>
+	    Alan Hayward  <alan.hayward@arm.com>
+	    David Sherwood  <david.sherwood@arm.com>
+
 	* target.def (preferred_simd_mode): Take a scalar_mode
 	instead of a machine_mode.
 	* targhooks.h (default_preferred_simd_mode): Likewise.

gcc/explow.c

@@ -787,6 +787,7 @@ promote_mode (const_tree type ATTRIBUTE_UNUSED, machine_mode mode,
 #ifdef PROMOTE_MODE
   enum tree_code code;
   int unsignedp;
+  scalar_mode smode;
 #endif
 
   /* For libcalls this is invoked without TYPE from the backends
@@ -806,9 +807,11 @@ promote_mode (const_tree type ATTRIBUTE_UNUSED, machine_mode mode,
     {
     case INTEGER_TYPE:   case ENUMERAL_TYPE:   case BOOLEAN_TYPE:
     case REAL_TYPE:      case OFFSET_TYPE:     case FIXED_POINT_TYPE:
-      PROMOTE_MODE (mode, unsignedp, type);
+      /* Values of these types always have scalar mode.  */
+      smode = as_a <scalar_mode> (mode);
+      PROMOTE_MODE (smode, unsignedp, type);
       *punsignedp = unsignedp;
-      return mode;
+      return smode;
 
 #ifdef POINTERS_EXTEND_UNSIGNED
     case REFERENCE_TYPE:

gcc/machmode.h

@@ -650,7 +650,7 @@ extern machine_mode bitwise_mode_for_mode (machine_mode);
 /* Return a mode that is suitable for representing a vector,
    or BLKmode on failure.  */
 
-extern machine_mode mode_for_vector (machine_mode, unsigned);
+extern machine_mode mode_for_vector (scalar_mode, unsigned);
 
 /* A class for iterating through possible bitfield modes.  */
 class bit_field_mode_iterator

gcc/sdbout.c

@@ -1281,11 +1281,15 @@ sdbout_parms (tree parms)
 		   the parm with the variable's declared type, and adjust
 		   the address if the least significant bytes (which we are
 		   using) are not the first ones.  */
+		scalar_mode from_mode, to_mode;
 		if (BYTES_BIG_ENDIAN
-		    && TREE_TYPE (parms) != DECL_ARG_TYPE (parms))
-		  current_sym_value +=
-		    (GET_MODE_SIZE (TYPE_MODE (DECL_ARG_TYPE (parms)))
-		     - GET_MODE_SIZE (GET_MODE (DECL_RTL (parms))));
+		    && TREE_TYPE (parms) != DECL_ARG_TYPE (parms)
+		    && is_a <scalar_mode> (TYPE_MODE (DECL_ARG_TYPE (parms)),
+					   &from_mode)
+		    && is_a <scalar_mode> (GET_MODE (DECL_RTL (parms)),
+					   &to_mode))
+		  current_sym_value += (GET_MODE_SIZE (from_mode)
+					- GET_MODE_SIZE (to_mode));
 
 		if (MEM_P (DECL_RTL (parms))
 		    && GET_CODE (XEXP (DECL_RTL (parms), 0)) == PLUS

gcc/stor-layout.c

@@ -478,7 +478,7 @@ bitwise_type_for_mode (machine_mode mode)
    is no suitable mode.  */
 
 machine_mode
-mode_for_vector (machine_mode innermode, unsigned nunits)
+mode_for_vector (scalar_mode innermode, unsigned nunits)
 {
   machine_mode mode;