Make more use of GET_MODE_UNIT_SIZE

This patch uses GET_MODE_UNIT_SIZE instead of GET_MODE_SIZE in
cases where, for compound modes, the mode of the scalar elements
is what matters.  E.g. the choice between truncation and extension
is really based on the modes of the consistuent scalars rather
than the mode as a whole.

None of the existing code was wrong.  The patch simply makes
things easier when converting to variable-sized modes.

2017-10-13  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* optabs.c (add_equal_note): Use GET_MODE_UNIT_SIZE.
	(widened_mode): Likewise.
	(expand_unop): Likewise.
	* ree.c (transform_ifelse): Likewise.
	(merge_def_and_ext): Likewise.
	(combine_reaching_defs): Likewise.
	* simplify-rtx.c (simplify_unary_operation_1): Likewise.

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

From-SVN: r253715

gcc/ChangeLog

@@ -2,6 +2,18 @@
 	    Alan Hayward  <alan.hayward@arm.com>
 	    David Sherwood  <david.sherwood@arm.com>
 
+	* optabs.c (add_equal_note): Use GET_MODE_UNIT_SIZE.
+	(widened_mode): Likewise.
+	(expand_unop): Likewise.
+	* ree.c (transform_ifelse): Likewise.
+	(merge_def_and_ext): Likewise.
+	(combine_reaching_defs): Likewise.
+	* simplify-rtx.c (simplify_unary_operation_1): Likewise.
+
+2017-10-13  Richard Sandiford  <richard.sandiford@linaro.org>
+	    Alan Hayward  <alan.hayward@arm.com>
+	    David Sherwood  <david.sherwood@arm.com>
+
 	* caller-save.c (replace_reg_with_saved_mem): Use byte_lowpart_offset.
 	* combine.c (gen_lowpart_for_combine): Likewise.
 	* dwarf2out.c (rtl_for_decl_location): Likewise.

gcc/optabs.c

@@ -138,8 +138,8 @@ add_equal_note (rtx_insn *insns, rtx target, enum rtx_code code, rtx op0, rtx op
 	if (GET_MODE (op0) != VOIDmode && GET_MODE (target) != GET_MODE (op0))
 	  {
 	    note = gen_rtx_fmt_e (code, GET_MODE (op0), copy_rtx (op0));
-	    if (GET_MODE_SIZE (GET_MODE (op0))
-		> GET_MODE_SIZE (GET_MODE (target)))
+	    if (GET_MODE_UNIT_SIZE (GET_MODE (op0))
+		> GET_MODE_UNIT_SIZE (GET_MODE (target)))
 	      note = simplify_gen_unary (TRUNCATE, GET_MODE (target),
 					 note, GET_MODE (op0));
 	    else
@@ -173,12 +173,12 @@ widened_mode (machine_mode to_mode, rtx op0, rtx op1)
 
   if (m0 == VOIDmode && m1 == VOIDmode)
     return to_mode;
-  else if (m0 == VOIDmode || GET_MODE_SIZE (m0) < GET_MODE_SIZE (m1))
+  else if (m0 == VOIDmode || GET_MODE_UNIT_SIZE (m0) < GET_MODE_UNIT_SIZE (m1))
     result = m1;
   else
     result = m0;
 
-  if (GET_MODE_SIZE (result) > GET_MODE_SIZE (to_mode))
+  if (GET_MODE_UNIT_SIZE (result) > GET_MODE_UNIT_SIZE (to_mode))
     return to_mode;
 
   return result;
@@ -2977,9 +2977,9 @@ expand_unop (machine_mode mode, optab unoptab, rtx op0, rtx target,
       else
 	{
 	  eq_value = gen_rtx_fmt_e (optab_to_code (unoptab), mode, op0);
-	  if (GET_MODE_SIZE (outmode) < GET_MODE_SIZE (mode))
+	  if (GET_MODE_UNIT_SIZE (outmode) < GET_MODE_UNIT_SIZE (mode))
 	    eq_value = simplify_gen_unary (TRUNCATE, outmode, eq_value, mode);
-	  else if (GET_MODE_SIZE (outmode) > GET_MODE_SIZE (mode))
+	  else if (GET_MODE_UNIT_SIZE (outmode) > GET_MODE_UNIT_SIZE (mode))
 	    eq_value = simplify_gen_unary (ZERO_EXTEND,
 					   outmode, eq_value, mode);
 	}

gcc/ree.c

@@ -428,7 +428,8 @@ transform_ifelse (ext_cand *cand, rtx_insn *def_insn)
   srcreg2 = XEXP (SET_SRC (set_insn), 2);
   /* If the conditional move already has the right or wider mode,
      there is nothing to do.  */
-  if (GET_MODE_SIZE (GET_MODE (dstreg)) >= GET_MODE_SIZE (cand->mode))
+  if (GET_MODE_UNIT_SIZE (GET_MODE (dstreg))
+      >= GET_MODE_UNIT_SIZE (cand->mode))
     return true;
 
   map_srcreg = gen_rtx_REG (cand->mode, REGNO (srcreg));
@@ -718,8 +719,8 @@ merge_def_and_ext (ext_cand *cand, rtx_insn *def_insn, ext_state *state)
 	      && state->modified[INSN_UID (def_insn)].mode
 		 == ext_src_mode)))
     {
-      if (GET_MODE_SIZE (GET_MODE (SET_DEST (*sub_rtx)))
-	  >= GET_MODE_SIZE (cand->mode))
+      if (GET_MODE_UNIT_SIZE (GET_MODE (SET_DEST (*sub_rtx)))
+	  >= GET_MODE_UNIT_SIZE (cand->mode))
 	return true;
       /* If def_insn is already scheduled to be deleted, don't attempt
 	 to modify it.  */
@@ -926,7 +927,8 @@ combine_reaching_defs (ext_cand *cand, const_rtx set_pat, ext_state *state)
 	  || (set = single_set (cand->insn)) == NULL_RTX)
 	return false;
       mode = GET_MODE (SET_DEST (set));
-      gcc_assert (GET_MODE_SIZE (mode) >= GET_MODE_SIZE (cand->mode));
+      gcc_assert (GET_MODE_UNIT_SIZE (mode)
+		  >= GET_MODE_UNIT_SIZE (cand->mode));
       cand->mode = mode;
     }
 

gcc/simplify-rtx.c

@@ -1272,10 +1272,9 @@ simplify_unary_operation_1 (enum rtx_code code, machine_mode mode, rtx op)
       if ((GET_CODE (op) == FLOAT_TRUNCATE
 	   && flag_unsafe_math_optimizations)
 	  || GET_CODE (op) == FLOAT_EXTEND)
-	return simplify_gen_unary (GET_MODE_SIZE (GET_MODE (XEXP (op,
-							    0)))
-				   > GET_MODE_SIZE (mode)
-				   ? FLOAT_TRUNCATE : FLOAT_EXTEND,
+	return simplify_gen_unary (GET_MODE_UNIT_SIZE (GET_MODE (XEXP (op, 0)))
+	  			   > GET_MODE_UNIT_SIZE (mode)
+	  			   ? FLOAT_TRUNCATE : FLOAT_EXTEND,
 				   mode,
 				   XEXP (op, 0), mode);