--- a/gdb/regcache.h
+++ b/gdb/regcache.h
@@ -206,6 +206,8 @@ extern struct type *register_type (struct gdbarch *gdbarch, int regnum);

 extern int register_size (struct gdbarch *gdbarch, int regnum);

+/* Return the size of the largest register.  */
+extern long max_register_size (struct gdbarch *gdbarch);

 /* Save/restore a register cache.  The set of registers saved /
    restored into the DST regcache determined by the save_reggroup /
diff --git a/gdb/regcache.c b/gdb/regcache.c
index 31aa1baf7ef69c27c00e45e3c8d4eb3c41dc4203..0da184cb7c6ea3a171139a40676658322e62ad2e 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -73,6 +73,9 @@ struct regcache_descr

   /* Cached table containing the type of each register.  */
   struct type **register_type;
+
+  /* Size of the largest register.  */
+  long max_register_size;
 };

 static void *
@@ -126,6 +129,8 @@ init_regcache_descr (struct gdbarch *gdbarch)
 	descr->register_offset[i] = offset;
 	offset += descr->sizeof_register[i];
 	gdb_assert (MAX_REGISTER_SIZE >= descr->sizeof_register[i]);
+	descr->max_register_size = std::max (descr->max_register_size,
+					     descr->sizeof_register[i]);
       }
     /* Set the real size of the raw register cache buffer.  */
     descr->sizeof_raw_registers = offset;
@@ -136,6 +141,8 @@ init_regcache_descr (struct gdbarch *gdbarch)
 	descr->register_offset[i] = offset;
 	offset += descr->sizeof_register[i];
 	gdb_assert (MAX_REGISTER_SIZE >= descr->sizeof_register[i]);
+	descr->max_register_size = std::max (descr->max_register_size,
+					     descr->sizeof_register[i]);
       }
     /* Set the real size of the readonly register cache buffer.  */
     descr->sizeof_cooked_registers = offset;
@@ -187,6 +194,13 @@ regcache_register_size (const struct regcache *regcache, int n)
   return register_size (get_regcache_arch (regcache), n);
 }

+long
+max_register_size (struct gdbarch *gdbarch)
+{
+  struct regcache_descr *descr = regcache_descr (gdbarch);
+  return descr->max_register_size;
+}
+
 /* The register cache for storing raw register values.  */

 struct regcache
@@ -327,7 +341,6 @@ regcache_save (struct regcache *dst, regcache_cooked_read_ftype *cooked_read,
 	       void *src)
 {
   struct gdbarch *gdbarch = dst->descr->gdbarch;
-  gdb_byte buf[MAX_REGISTER_SIZE];
   int regnum;

   /* The DST should be `read-only', if it wasn't then the save would
@@ -346,17 +359,13 @@ regcache_save (struct regcache *dst, regcache_cooked_read_ftype *cooked_read,
     {
       if (gdbarch_register_reggroup_p (gdbarch, regnum, save_reggroup))
 	{
-	  enum register_status status = cooked_read (src, regnum, buf);
+	  gdb_byte *dst_buf = register_buffer (dst, regnum);
+	  enum register_status status = cooked_read (src, regnum, dst_buf);

-	  if (status == REG_VALID)
-	    memcpy (register_buffer (dst, regnum), buf,
-		    register_size (gdbarch, regnum));
-	  else
+	  if (status != REG_VALID)
 	    {
 	      gdb_assert (status != REG_UNKNOWN);
-
-	      memset (register_buffer (dst, regnum), 0,
-		      register_size (gdbarch, regnum));
+	      memset (dst_buf, 0, register_size (gdbarch, regnum));
 	    }
 	  dst->register_status[regnum] = status;
 	}
@@ -369,7 +378,7 @@ regcache_restore (struct regcache *dst,
 		  void *cooked_read_context)
 {
   struct gdbarch *gdbarch = dst->descr->gdbarch;
-  gdb_byte buf[MAX_REGISTER_SIZE];
+  std::vector<gdb_byte> buf (max_register_size (gdbarch));
   int regnum;

   /* The dst had better not be read-only.  If it is, the `restore'
@@ -385,9 +394,9 @@ regcache_restore (struct regcache *dst,
 	{
 	  enum register_status status;

-	  status = cooked_read (cooked_read_context, regnum, buf);
+	  status = cooked_read (cooked_read_context, regnum, buf.data ());
 	  if (status == REG_VALID)
-	    regcache_cooked_write (dst, regnum, buf);
+	    regcache_cooked_write (dst, regnum, buf.data ());
 	}
     }
 }
@@ -1324,7 +1333,6 @@ regcache_dump (struct regcache *regcache, struct ui_file *file,
   int footnote_register_offset = 0;
   int footnote_register_type_name_null = 0;
   long register_offset = 0;
-  gdb_byte buf[MAX_REGISTER_SIZE];

 #if 0
   fprintf_unfiltered (file, "nr_raw_registers %d\n",
@@ -1451,8 +1459,8 @@ regcache_dump (struct regcache *regcache, struct ui_file *file,
 	    fprintf_unfiltered (file, "<unavailable>");
 	  else
 	    {
-	      regcache_raw_read (regcache, regnum, buf);
-	      print_hex_chars (file, buf,
+	      regcache_raw_update (regcache, regnum);
+	      print_hex_chars (file, register_buffer (regcache, regnum),
 			       regcache->descr->sizeof_register[regnum],
 			       gdbarch_byte_order (gdbarch));
 	    }
@@ -1465,17 +1473,19 @@ regcache_dump (struct regcache *regcache, struct ui_file *file,
 	    fprintf_unfiltered (file, "Cooked value");
 	  else
 	    {
-	      enum register_status status;
+	      struct value *value = regcache_cooked_read_value (regcache,
+								regnum);

-	      status = regcache_cooked_read (regcache, regnum, buf);
-	      if (status == REG_UNKNOWN)
-		fprintf_unfiltered (file, "<invalid>");
-	      else if (status == REG_UNAVAILABLE)
+	      if (value_optimized_out (value)
+		  || !value_entirely_available (value))
 		fprintf_unfiltered (file, "<unavailable>");
 	      else
-		print_hex_chars (file, buf,
+		print_hex_chars (file, value_contents_all (value),
 				 regcache->descr->sizeof_register[regnum],
 				 gdbarch_byte_order (gdbarch));
+
+	      release_value (value);
+	      value_free (value);
 	    }
 	}

