Index: gcc/machmode.h
===================================================================
--- gcc/machmode.h	(revision 235529)
+++ gcc/machmode.h	(working copy)
@@ -269,6 +269,10 @@ extern const unsigned char mode_wider[NU
 extern const unsigned char mode_2xwider[NUM_MACHINE_MODES];
 #define GET_MODE_2XWIDER_MODE(MODE) ((machine_mode) mode_2xwider[MODE])
 
+/* Get the complex mode from the component mode.  */
+extern const unsigned char mode_complex[NUM_MACHINE_MODES];
+#define GET_MODE_COMPLEX_MODE(MODE) ((machine_mode) mode_complex[MODE])
+
 /* Return the mode for data of a given size SIZE and mode class CLASS.
    If LIMIT is nonzero, then don't use modes bigger than MAX_FIXED_MODE_SIZE.
    The value is BLKmode if no other mode is found.  */
Index: gcc/stor-layout.c
===================================================================
--- gcc/stor-layout.c	(revision 235529)
+++ gcc/stor-layout.c	(working copy)
@@ -2146,11 +2146,19 @@ layout_type (tree type)
 
     case COMPLEX_TYPE:
       TYPE_UNSIGNED (type) = TYPE_UNSIGNED (TREE_TYPE (type));
-      SET_TYPE_MODE (type,
-		     mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
-				    (TREE_CODE (TREE_TYPE (type)) == REAL_TYPE
-				     ? MODE_COMPLEX_FLOAT : MODE_COMPLEX_INT),
-				     0));
+
+      /* build_complex_type has set the expected mode to allow having multiple
+	 complex types for multiple floating point types that have the same
+	 size such as the PowerPC with __ibm128 and __float128.  If this was
+	 not set, figure out the mode manually.  */
+      if (TYPE_MODE (type) == VOIDmode)
+	{
+	  unsigned int precision = TYPE_PRECISION (TREE_TYPE (type));
+	  enum mode_class mclass = (TREE_CODE (TREE_TYPE (type)) == REAL_TYPE
+				    ? MODE_COMPLEX_FLOAT : MODE_COMPLEX_INT);
+	  SET_TYPE_MODE (type, mode_for_size (2 * precision, mclass, 0));
+	}
+
       TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
       TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
       break;
Index: gcc/genmodes.c
===================================================================
--- gcc/genmodes.c	(revision 235529)
+++ gcc/genmodes.c	(working copy)
@@ -66,6 +66,7 @@ struct mode_data
 				   this mode as a component.  */
   struct mode_data *next_cont;  /* Next mode in that list.  */
 
+  struct mode_data *complex;	/* complex type with mode as component.  */
   const char *file;		/* file and line of definition, */
   unsigned int line;		/* for error reporting */
   unsigned int counter;		/* Rank ordering of modes */
@@ -83,7 +84,7 @@ static struct mode_data *void_mode;
 static const struct mode_data blank_mode = {
   0, "<unknown>", MAX_MODE_CLASS,
   -1U, -1U, -1U, -1U,
-  0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0,
   "<unknown>", 0, 0, 0, 0, false, 0
 };
 
@@ -472,6 +473,7 @@ make_complex_modes (enum mode_class cl,
 
       c = new_mode (cclass, buf, file, line);
       c->component = m;
+      m->complex = c;
     }
 }
 
@@ -1381,6 +1383,22 @@ emit_mode_wider (void)
 }
 
 static void
+emit_mode_complex (void)
+{
+  int c;
+  struct mode_data *m;
+
+  print_decl ("unsigned char", "mode_complex", "NUM_MACHINE_MODES");
+
+  for_all_modes (c, m)
+    tagged_printf ("%smode",
+		   m->complex ? m->complex->name : void_mode->name,
+		   m->name);
+
+  print_closer ();
+}
+
+static void
 emit_mode_mask (void)
 {
   int c;
@@ -1745,6 +1763,7 @@ emit_insn_modes_c (void)
   emit_mode_size ();
   emit_mode_nunits ();
   emit_mode_wider ();
+  emit_mode_complex ();
   emit_mode_mask ();
   emit_mode_inner ();
   emit_mode_unit_size ();
Index: gcc/tree.c
===================================================================
--- gcc/tree.c	(revision 235529)
+++ gcc/tree.c	(working copy)
@@ -8767,6 +8767,7 @@ build_complex_type (tree component_type)
   t = make_node (COMPLEX_TYPE);
 
   TREE_TYPE (t) = TYPE_MAIN_VARIANT (component_type);
+  SET_TYPE_MODE (t, GET_MODE_COMPLEX_MODE (TYPE_MODE (component_type)));
 
   /* If we already have such a type, use the old one.  */
   hstate.add_object (TYPE_HASH (component_type));