[4/77] Add FOR_EACH iterators for modes

The new iterators are:

- FOR_EACH_MODE_IN_CLASS: iterate over all the modes in a mode class.

- FOR_EACH_MODE_FROM: iterate over all the modes in a class,
  starting at a given mode.

- FOR_EACH_WIDER_MODE: iterate over all the modes in a class,
  starting at the next widest mode after a given mode.

- FOR_EACH_2XWIDER_MODE: same, but considering only modes that
  are two times wider than the previous mode.

- FOR_EACH_MODE_UNTIL: iterate over all the modes in a class until
  a given mode is reached.

- FOR_EACH_MODE: iterate over all the modes in a class between
  two given modes, inclusive of the first but not the second.

These help with the stronger type checking added by later patches,
since every new mode will be in the same class as the previous one.

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_traits): New structure.
	(get_narrowest_mode): New function.
	(mode_iterator::start): Likewise.
	(mode_iterator::iterate_p): Likewise.
	(mode_iterator::get_wider): Likewise.
	(mode_iterator::get_known_wider): Likewise.
	(mode_iterator::get_2xwider): Likewise.
	(FOR_EACH_MODE_IN_CLASS): New mode iterator.
	(FOR_EACH_MODE): Likewise.
	(FOR_EACH_MODE_FROM): Likewise.
	(FOR_EACH_MODE_UNTIL): Likewise.
	(FOR_EACH_WIDER_MODE): Likewise.
	(FOR_EACH_2XWIDER_MODE): Likewise.
	* builtins.c (expand_builtin_strlen): Use new mode iterators.
	* combine.c (simplify_comparison): Likewise
	* config/i386/i386.c (type_natural_mode): Likewise.
	* cse.c (cse_insn): Likewise.
	* dse.c (find_shift_sequence): Likewise.
	* emit-rtl.c (init_derived_machine_modes): Likewise.
	(init_emit_once): Likewise.
	* explow.c (hard_function_value): Likewise.
	* expmed.c (extract_fixed_bit_field_1): Likewise.
	(extract_bit_field_1): Likewise.
	(expand_divmod): Likewise.
	(emit_store_flag_1): Likewise.
	* expr.c (init_expr_target): Likewise.
	(convert_move): Likewise.
	(alignment_for_piecewise_move): Likewise.
	(widest_int_mode_for_size): Likewise.
	(emit_block_move_via_movmem): Likewise.
	(copy_blkmode_to_reg): Likewise.
	(set_storage_via_setmem): Likewise.
	(compress_float_constant): Likewise.
	* omp-low.c (omp_clause_aligned_alignment): Likewise.
	* optabs-query.c (get_best_extraction_insn): Likewise.
	* optabs.c (expand_binop): Likewise.
	(expand_twoval_unop): Likewise.
	(expand_twoval_binop): Likewise.
	(widen_leading): Likewise.
	(widen_bswap): Likewise.
	(expand_parity): Likewise.
	(expand_unop): Likewise.
	(prepare_cmp_insn): Likewise.
	(prepare_float_lib_cmp): Likewise.
	(expand_float): Likewise.
	(expand_fix): Likewise.
	(expand_sfix_optab): Likewise.
	* postreload.c (move2add_use_add2_insn): Likewise.
	* reg-stack.c (reg_to_stack): Likewise.
	* reginfo.c (choose_hard_reg_mode): Likewise.
	* rtlanal.c (init_num_sign_bit_copies_in_rep): Likewise.
	* stor-layout.c (mode_for_size): Likewise.
	(smallest_mode_for_size): Likewise.
	(mode_for_vector): Likewise.
	(finish_bitfield_representative): Likewise.
	* tree-ssa-math-opts.c (target_supports_divmod_p): Likewise.
	* tree-vect-generic.c (type_for_widest_vector_mode): Likewise.
	* tree-vect-stmts.c (vectorizable_conversion): Likewise.
	* var-tracking.c (prepare_call_arguments): Likewise.

gcc/ada/
	* gcc-interface/misc.c (fp_prec_to_size): Use new mode iterators.
	(fp_size_to_prec): Likewise.

gcc/c-family/
	* c-common.c (c_common_fixed_point_type_for_size): Use new mode
	iterators.
	* c-cppbuiltin.c (c_cpp_builtins): Likewise.

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

From-SVN: r251455

1 files changed, 16 insertions, 24 deletions

diff --git a/gcc/expr.c b/gcc/expr.c
index 7f34f5d..cbec00c 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -177,12 +177,10 @@ init_expr_target (void)
 
   mem = gen_rtx_MEM (VOIDmode, gen_raw_REG (Pmode, LAST_VIRTUAL_REGISTER + 1));
 
-  for (mode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT); mode != VOIDmode;
-       mode = GET_MODE_WIDER_MODE (mode))
+  FOR_EACH_MODE_IN_CLASS (mode, MODE_FLOAT)
     {
       machine_mode srcmode;
-      for (srcmode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT); srcmode != mode;
-	   srcmode = GET_MODE_WIDER_MODE (srcmode))
+      FOR_EACH_MODE_UNTIL (srcmode, mode)
 	{
 	  enum insn_code ic;
 
@@ -549,8 +547,7 @@ convert_move (rtx to, rtx from, int unsignedp)
 	  int shift_amount;
 
 	  /* Search for a mode to convert via.  */
-	  for (intermediate = from_mode; intermediate != VOIDmode;
-	       intermediate = GET_MODE_WIDER_MODE (intermediate))
+	  FOR_EACH_MODE_FROM (intermediate, from_mode)
 	    if (((can_extend_p (to_mode, intermediate, unsignedp)
 		  != CODE_FOR_nothing)
 		 || (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (intermediate)
@@ -702,12 +699,14 @@ alignment_for_piecewise_move (unsigned int max_pieces, unsigned int align)
     {
       machine_mode tmode, xmode;
 
-      for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT), xmode = tmode;
-	   tmode != VOIDmode;
-	   xmode = tmode, tmode = GET_MODE_WIDER_MODE (tmode))
-	if (GET_MODE_SIZE (tmode) > max_pieces
-	    || SLOW_UNALIGNED_ACCESS (tmode, align))
-	  break;
+      xmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
+      FOR_EACH_MODE_IN_CLASS (tmode, MODE_INT)
+	{
+	  if (GET_MODE_SIZE (tmode) > max_pieces
+	      || SLOW_UNALIGNED_ACCESS (tmode, align))
+	    break;
+	  xmode = tmode;
+	}
 
       align = MAX (align, GET_MODE_ALIGNMENT (xmode));
     }
@@ -723,8 +722,7 @@ widest_int_mode_for_size (unsigned int size)
 {
   machine_mode tmode, mode = VOIDmode;
 
-  for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
-       tmode != VOIDmode; tmode = GET_MODE_WIDER_MODE (tmode))
+  FOR_EACH_MODE_IN_CLASS (tmode, MODE_INT)
     if (GET_MODE_SIZE (tmode) < size)
       mode = tmode;
 
@@ -1728,8 +1726,7 @@ emit_block_move_via_movmem (rtx x, rtx y, rtx size, unsigned int align,
      including more than one in the machine description unless
      the more limited one has some advantage.  */
 
-  for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
-       mode = GET_MODE_WIDER_MODE (mode))
+  FOR_EACH_MODE_IN_CLASS (mode, MODE_INT)
     {
       enum insn_code code = direct_optab_handler (movmem_optab, mode);
 
@@ -2790,9 +2787,7 @@ copy_blkmode_to_reg (machine_mode mode, tree src)
     {
       /* Find the smallest integer mode large enough to hold the
 	 entire structure.  */
-      for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
-	   mode != VOIDmode;
-	   mode = GET_MODE_WIDER_MODE (mode))
+      FOR_EACH_MODE_IN_CLASS (mode, MODE_INT)
 	/* Have we found a large enough mode?  */
 	if (GET_MODE_SIZE (mode) >= bytes)
 	  break;
@@ -3048,8 +3043,7 @@ set_storage_via_setmem (rtx object, rtx size, rtx val, unsigned int align,
 	expected_size = min_size;
     }
 
-  for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
-       mode = GET_MODE_WIDER_MODE (mode))
+  FOR_EACH_MODE_IN_CLASS (mode, MODE_INT)
     {
       enum insn_code code = direct_optab_handler (setmem_optab, mode);
 
@@ -3788,9 +3782,7 @@ compress_float_constant (rtx x, rtx y)
   else
     oldcost = set_src_cost (force_const_mem (dstmode, y), dstmode, speed);
 
-  for (srcmode = GET_CLASS_NARROWEST_MODE (GET_MODE_CLASS (orig_srcmode));
-       srcmode != orig_srcmode;
-       srcmode = GET_MODE_WIDER_MODE (srcmode))
+  FOR_EACH_MODE_UNTIL (srcmode, orig_srcmode)
     {
       enum insn_code ic;
       rtx trunc_y;