[09/nn] Add a fixed_size_mode_pod class

[Richard Sandiford]

This patch adds a POD version of fixed_size_mode.  The only current use
is for storing the __builtin_apply and __builtin_result register modes,
which were made fixed_size_modes by the previous patch.


2017-10-23  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* coretypes.h (fixed_size_mode): Declare.
	(fixed_size_mode_pod): New typedef.
	* builtins.h (target_builtins::x_apply_args_mode)
	(target_builtins::x_apply_result_mode): Change type to
	fixed_size_mode_pod.
	* builtins.c (apply_args_size, apply_result_size, result_vector)
	(expand_builtin_apply_args_1, expand_builtin_apply)
	(expand_builtin_return): Update accordingly.

Index: gcc/coretypes.h
===================================================================
--- gcc/coretypes.h	2017-09-11 17:10:58.656085547 +0100
+++ gcc/coretypes.h	2017-10-23 11:42:57.592545063 +0100
@@ -59,6 +59,7 @@ typedef const struct rtx_def *const_rtx;
 class scalar_int_mode;
 class scalar_float_mode;
 class complex_mode;
+class fixed_size_mode;
 template<typename> class opt_mode;
 typedef opt_mode<scalar_mode> opt_scalar_mode;
 typedef opt_mode<scalar_int_mode> opt_scalar_int_mode;
@@ -66,6 +67,7 @@ typedef opt_mode<scalar_float_mode> opt_
 template<typename> class pod_mode;
 typedef pod_mode<scalar_mode> scalar_mode_pod;
 typedef pod_mode<scalar_int_mode> scalar_int_mode_pod;
+typedef pod_mode<fixed_size_mode> fixed_size_mode_pod;
 
 /* Subclasses of rtx_def, using indentation to show the class
    hierarchy, along with the relevant invariant.
Index: gcc/builtins.h
===================================================================
--- gcc/builtins.h	2017-08-30 12:18:46.602740973 +0100
+++ gcc/builtins.h	2017-10-23 11:42:57.592545063 +0100
@@ -29,14 +29,14 @@ struct target_builtins {
      the register is not used for calling a function.  If the machine
      has register windows, this gives only the outbound registers.
      INCOMING_REGNO gives the corresponding inbound register.  */
-  machine_mode x_apply_args_mode[FIRST_PSEUDO_REGISTER];
+  fixed_size_mode_pod x_apply_args_mode[FIRST_PSEUDO_REGISTER];
 
   /* For each register that may be used for returning values, this gives
      a mode used to copy the register's value.  VOIDmode indicates the
      register is not used for returning values.  If the machine has
      register windows, this gives only the outbound registers.
      INCOMING_REGNO gives the corresponding inbound register.  */
-  machine_mode x_apply_result_mode[FIRST_PSEUDO_REGISTER];
+  fixed_size_mode_pod x_apply_result_mode[FIRST_PSEUDO_REGISTER];
 };
 
 extern struct target_builtins default_target_builtins;
Index: gcc/builtins.c
===================================================================
--- gcc/builtins.c	2017-10-23 11:41:23.140260335 +0100
+++ gcc/builtins.c	2017-10-23 11:42:57.592545063 +0100
@@ -1358,7 +1358,6 @@ apply_args_size (void)
   static int size = -1;
   int align;
   unsigned int regno;
-  machine_mode mode;
 
   /* The values computed by this function never change.  */
   if (size < 0)
@@ -1374,7 +1373,7 @@ apply_args_size (void)
       for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
 	if (FUNCTION_ARG_REGNO_P (regno))
 	  {
-	    mode = targetm.calls.get_raw_arg_mode (regno);
+	    fixed_size_mode mode = targetm.calls.get_raw_arg_mode (regno);
 
 	    gcc_assert (mode != VOIDmode);
 
@@ -1386,7 +1385,7 @@ apply_args_size (void)
 	  }
 	else
 	  {
-	    apply_args_mode[regno] = VOIDmode;
+	    apply_args_mode[regno] = as_a <fixed_size_mode> (VOIDmode);
 	  }
     }
   return size;
@@ -1400,7 +1399,6 @@ apply_result_size (void)
 {
   static int size = -1;
   int align, regno;
-  machine_mode mode;
 
   /* The values computed by this function never change.  */
   if (size < 0)
@@ -1410,7 +1408,7 @@ apply_result_size (void)
       for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
 	if (targetm.calls.function_value_regno_p (regno))
 	  {
-	    mode = targetm.calls.get_raw_result_mode (regno);
+	    fixed_size_mode mode = targetm.calls.get_raw_result_mode (regno);
 
 	    gcc_assert (mode != VOIDmode);
 
@@ -1421,7 +1419,7 @@ apply_result_size (void)
 	    apply_result_mode[regno] = mode;
 	  }
 	else
-	  apply_result_mode[regno] = VOIDmode;
+	  apply_result_mode[regno] = as_a <fixed_size_mode> (VOIDmode);
 
       /* Allow targets that use untyped_call and untyped_return to override
 	 the size so that machine-specific information can be stored here.  */
@@ -1440,7 +1438,7 @@ apply_result_size (void)
 result_vector (int savep, rtx result)
 {
   int regno, size, align, nelts;
-  machine_mode mode;
+  fixed_size_mode mode;
   rtx reg, mem;
   rtx *savevec = XALLOCAVEC (rtx, FIRST_PSEUDO_REGISTER);
 
@@ -1469,7 +1467,7 @@ expand_builtin_apply_args_1 (void)
 {
   rtx registers, tem;
   int size, align, regno;
-  machine_mode mode;
+  fixed_size_mode mode;
   rtx struct_incoming_value = targetm.calls.struct_value_rtx (cfun ? TREE_TYPE (cfun->decl) : 0, 1);
 
   /* Create a block where the arg-pointer, structure value address,
@@ -1573,7 +1571,7 @@ expand_builtin_apply_args (void)
 expand_builtin_apply (rtx function, rtx arguments, rtx argsize)
 {
   int size, align, regno;
-  machine_mode mode;
+  fixed_size_mode mode;
   rtx incoming_args, result, reg, dest, src;
   rtx_call_insn *call_insn;
   rtx old_stack_level = 0;
@@ -1734,7 +1732,7 @@ expand_builtin_apply (rtx function, rtx
 expand_builtin_return (rtx result)
 {
   int size, align, regno;
-  machine_mode mode;
+  fixed_size_mode mode;
   rtx reg;
   rtx_insn *call_fusage = 0;