[18/77] Make int_mode_for_mode return an opt_scalar_int_mode

Also use int_mode_for_mode instead of (int_)mode_for_size
in cases where the requested size was the bitsize of an
existing mode.

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

gcc/
	* machmode.h (opt_mode::else_blk): New function.
	(int_mode_for_mode): Declare.
	* stor-layout.c (int_mode_for_mode): Return an opt_scalar_int_mode.
	* builtins.c (expand_builtin_signbit): Adjust for new int_mode_for_mode
	return type.
	* cfgexpand.c (expand_debug_expr): Likewise.
	* combine.c (gen_lowpart_or_truncate): Likewise.
	(gen_lowpart_for_combine): Likewise.
	* config/aarch64/aarch64.c (aarch64_emit_approx_sqrt): Likewise.
	* config/avr/avr.c (avr_to_int_mode): Likewise.
	(avr_out_plus_1): Likewise.
	(avr_out_plus): Likewise.
	(avr_out_round): Likewise.
	* config/i386/i386.c (ix86_split_to_parts): Likewise.
	* config/s390/s390.c (s390_expand_vec_compare_cc): Likewise.
	(s390_expand_vcond): Likewise.
	* config/spu/spu.c (spu_split_immediate): Likewise.
	(spu_expand_mov): Likewise.
	* dse.c (get_stored_val): Likewise.
	* expmed.c (store_bit_field_1): Likewise.
	(convert_extracted_bit_field): Use int_mode_for_mode instead of
	int_mode_for_size.
	(extract_bit_field_1): Adjust for new int_mode_for_mode return type.
	(extract_low_bits): Likewise.
	* expr.c (emit_group_load_1): Likewise.  Separate out the BLKmode
	handling rather than repeating the check.
	(emit_group_store): Likewise.
	(emit_move_via_integer): Adjust for new int_mode_for_mode return type.
	* optabs.c (expand_absneg_bit): Likewise.
	(expand_copysign_absneg): Likewise.
	(expand_copysign_bit): Likewise.
	* tree-if-conv.c (ifcvt_can_use_mask_load_store): Likewise.
	* tree-vect-slp.c (vect_transform_slp_perm_load): Likewise.
	* tree-vect-stmts.c (vect_gen_perm_mask_any): Likewise.
	* var-tracking.c (prepare_call_arguments):  Likewise.
	* config/powerpcspe/powerpcspe.c (rs6000_do_expand_vec_perm): Use
	int_mode_for_mode instead of mode_for_size.
	* config/rs6000/rs6000.c (rs6000_do_expand_vec_perm): Likewise.

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

From-SVN: r251470

1 files changed, 5 insertions, 8 deletions

diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 433fd99..f1a601b 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -364,16 +364,16 @@ smallest_mode_for_size (unsigned int size, enum mode_class mclass)
   return mode;
 }
 
-/* Find an integer mode of the exact same size, or BLKmode on failure.  */
+/* Return an integer mode of exactly the same size as MODE, if one exists.  */
 
-machine_mode
+opt_scalar_int_mode
 int_mode_for_mode (machine_mode mode)
 {
   switch (GET_MODE_CLASS (mode))
     {
     case MODE_INT:
     case MODE_PARTIAL_INT:
-      break;
+      return as_a <scalar_int_mode> (mode);
 
     case MODE_COMPLEX_INT:
     case MODE_COMPLEX_FLOAT:
@@ -390,12 +390,11 @@ int_mode_for_mode (machine_mode mode)
     case MODE_VECTOR_UFRACT:
     case MODE_VECTOR_UACCUM:
     case MODE_POINTER_BOUNDS:
-      mode = mode_for_size (GET_MODE_BITSIZE (mode), MODE_INT, 0);
-      break;
+      return int_mode_for_size (GET_MODE_BITSIZE (mode), 0);
 
     case MODE_RANDOM:
       if (mode == BLKmode)
-	break;
+	return opt_scalar_int_mode ();
 
       /* fall through */
 
@@ -403,8 +402,6 @@ int_mode_for_mode (machine_mode mode)
     default:
       gcc_unreachable ();
     }
-
-  return mode;
 }
 
 /* Find a mode that can be used for efficient bitwise operations on MODE.