re PR tree-optimization/68961 (Test case gcc.target/powerpc/pr60203.c fails since r231674)

2016-06-29  Richard Biener  <rguenther@suse.de>

	PR rtl-optimization/68961
	* simplify-rtx.c (simplify_subreg): Handle VEC_CONCAT like CONCAT.

From-SVN: r237840

gcc/ChangeLog

 2016-06-29  Richard Biener  <rguenther@suse.de>
 
+	PR rtl-optimization/68961
+	* simplify-rtx.c (simplify_subreg): Handle VEC_CONCAT like CONCAT.
+
+2016-06-29  Richard Biener  <rguenther@suse.de>
+
 	PR middle-end/71002
 	* alias.c (component_uses_parent_alias_set_from): Handle
 	type punning through union accesses by using the union alias set.

gcc/simplify-rtx.c

@@ -6108,9 +6108,10 @@ simplify_subreg (machine_mode outermode, rtx op,
       && GET_MODE_SIZE (outermode) <= GET_MODE_SIZE (GET_MODE (op)))
     return adjust_address_nv (op, outermode, byte);
 
-  /* Handle complex values represented as CONCAT
-     of real and imaginary part.  */
-  if (GET_CODE (op) == CONCAT)
+  /* Handle complex or vector values represented as CONCAT or VEC_CONCAT
+     of two parts.  */
+  if (GET_CODE (op) == CONCAT
+      || GET_CODE (op) == VEC_CONCAT)
     {
       unsigned int part_size, final_offset;
       rtx part, res;
@@ -6130,10 +6131,13 @@ simplify_subreg (machine_mode outermode, rtx op,
       if (final_offset + GET_MODE_SIZE (outermode) > part_size)
 	return NULL_RTX;
 
-      res = simplify_subreg (outermode, part, GET_MODE (part), final_offset);
+      enum machine_mode part_mode = GET_MODE (part);
+      if (part_mode == VOIDmode)
+	part_mode = GET_MODE_INNER (GET_MODE (op));
+      res = simplify_subreg (outermode, part, part_mode, final_offset);
       if (res)
 	return res;
-      if (validate_subreg (outermode, GET_MODE (part), part, final_offset))
+      if (validate_subreg (outermode, part_mode, part, final_offset))
 	return gen_rtx_SUBREG (outermode, part, final_offset);
       return NULL_RTX;
     }