[105/nnn] poly_int: expand_assignment

[Richard Sandiford]

This patch makes the CONCAT handing in expand_assignment cope with
polynomial mode sizes.  The mode of the CONCAT must be complex,
so we can base the tests on the sizes of the real and imaginary
components.


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

gcc/
	* expr.c (expand_assignment): Cope with polynomial mode sizes
	when assigning to a CONCAT.

Index: gcc/expr.c
===================================================================
--- gcc/expr.c	2017-10-23 17:25:54.178292230 +0100
+++ gcc/expr.c	2017-10-23 17:25:56.086223649 +0100
@@ -5109,32 +5109,36 @@ expand_assignment (tree to, tree from, b
       /* Handle expand_expr of a complex value returning a CONCAT.  */
       else if (GET_CODE (to_rtx) == CONCAT)
 	{
-	  unsigned short mode_bitsize = GET_MODE_BITSIZE (GET_MODE (to_rtx));
+	  machine_mode to_mode = GET_MODE (to_rtx);
+	  gcc_checking_assert (COMPLEX_MODE_P (to_mode));
+	  poly_int64 mode_bitsize = GET_MODE_BITSIZE (to_mode);
+	  unsigned short inner_bitsize = GET_MODE_UNIT_BITSIZE (to_mode);
 	  if (COMPLEX_MODE_P (TYPE_MODE (TREE_TYPE (from)))
 	      && known_zero (bitpos)
 	      && must_eq (bitsize, mode_bitsize))
 	    result = store_expr (from, to_rtx, false, nontemporal, reversep);
-	  else if (must_eq (bitsize, mode_bitsize / 2)
+	  else if (must_eq (bitsize, inner_bitsize)
 		   && (known_zero (bitpos)
-		       || must_eq (bitpos, mode_bitsize / 2)))
+		       || must_eq (bitpos, inner_bitsize)))
 	    result = store_expr (from, XEXP (to_rtx, maybe_nonzero (bitpos)),
 				 false, nontemporal, reversep);
-	  else if (must_le (bitpos + bitsize, mode_bitsize / 2))
+	  else if (must_le (bitpos + bitsize, inner_bitsize))
 	    result = store_field (XEXP (to_rtx, 0), bitsize, bitpos,
 				  bitregion_start, bitregion_end,
 				  mode1, from, get_alias_set (to),
 				  nontemporal, reversep);
-	  else if (must_ge (bitpos, mode_bitsize / 2))
+	  else if (must_ge (bitpos, inner_bitsize))
 	    result = store_field (XEXP (to_rtx, 1), bitsize,
-				  bitpos - mode_bitsize / 2,
+				  bitpos - inner_bitsize,
 				  bitregion_start, bitregion_end,
 				  mode1, from, get_alias_set (to),
 				  nontemporal, reversep);
-	  else if (known_zero (bitpos) && must_eq (bitsize, mode_bitsize))
+	  else if (known_zero (bitpos)
+		   && must_eq (bitsize, mode_bitsize))
 	    {
 	      rtx from_rtx;
 	      result = expand_normal (from);
-	      from_rtx = simplify_gen_subreg (GET_MODE (to_rtx), result,
+	      from_rtx = simplify_gen_subreg (to_mode, result,
 					      TYPE_MODE (TREE_TYPE (from)), 0);
 	      emit_move_insn (XEXP (to_rtx, 0),
 			      read_complex_part (from_rtx, false));