[PATCH] Shrink LTO bytecode

[Richard Biener]

This shrinks LTO_tree_pickle_reference and all LTO headers by
using uhwi streaming instead of fixed-size streaming for
streamer_write_hwi_in_range/streamer_read_hwi_in_range.
LTO_tree_pickle_reference are the most issued records so it's
worth optimizing its placement so it can use a 1 byte record.

LTO bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.

Richard.

2013-06-06  Richard Biener  <rguenther@suse.de>

	* lto-streamer.h (enum LTO_tags): Move LTO_tree_pickle_reference
	after LTO_null.
	(lto_tag_is_tree_code_p): Adjust.
	(lto_tag_is_gimple_code_p): Likewise.
	(lto_gimple_code_to_tag): Likewise.
	(lto_tag_to_gimple_code): Likewise.
	(lto_tree_code_to_tag): Likewise.
	(lto_tag_to_tree_code): Likewise.
	* data-streamer.h (streamer_write_hwi_in_range): Use
	uhwi streaming to stream the normalized range.
	(streamer_read_hwi_in_range): Likewise.

Index: gcc/lto-streamer.h
===================================================================
--- gcc/lto-streamer.h	(revision 199720)
+++ gcc/lto-streamer.h	(working copy)
@@ -155,6 +155,9 @@ enum LTO_tags
 {
   LTO_null = 0,
 
+  /* Special for streamer.  Reference to previously-streamed node.  */
+  LTO_tree_pickle_reference,
+
   /* Reserve enough entries to fit all the tree and gimple codes handled
      by the streamer.  This guarantees that:
 
@@ -196,9 +199,6 @@ enum LTO_tags
   /* EH try/catch node.  */
   LTO_eh_catch,
 
-  /* Special for global streamer. Reference to previously-streamed node.  */
-  LTO_tree_pickle_reference,
-
   /* References to indexable tree nodes.  These objects are stored in
      tables that are written separately from the function bodies that
      reference them.  This way they can be instantiated even when the
@@ -921,7 +921,7 @@ extern vec<lto_out_decl_state_ptr> lto_f
 static inline bool
 lto_tag_is_tree_code_p (enum LTO_tags tag)
 {
-  return tag > LTO_null && (unsigned) tag <= MAX_TREE_CODES;
+  return tag > LTO_tree_pickle_reference && (unsigned) tag <= MAX_TREE_CODES;
 }
 
 
@@ -929,8 +929,8 @@ lto_tag_is_tree_code_p (enum LTO_tags ta
 static inline bool
 lto_tag_is_gimple_code_p (enum LTO_tags tag)
 {
-  return (unsigned) tag >= NUM_TREE_CODES + 1
-	 && (unsigned) tag < 1 + NUM_TREE_CODES + LAST_AND_UNUSED_GIMPLE_CODE;
+  return (unsigned) tag >= NUM_TREE_CODES + 2
+	 && (unsigned) tag < 2 + NUM_TREE_CODES + LAST_AND_UNUSED_GIMPLE_CODE;
 }
 
 
@@ -939,7 +939,7 @@ lto_tag_is_gimple_code_p (enum LTO_tags
 static inline enum LTO_tags
 lto_gimple_code_to_tag (enum gimple_code code)
 {
-  return (enum LTO_tags) ((unsigned) code + NUM_TREE_CODES + 1);
+  return (enum LTO_tags) ((unsigned) code + NUM_TREE_CODES + 2);
 }
 
 
@@ -949,7 +949,7 @@ static inline enum gimple_code
 lto_tag_to_gimple_code (enum LTO_tags tag)
 {
   gcc_assert (lto_tag_is_gimple_code_p (tag));
-  return (enum gimple_code) ((unsigned) tag - NUM_TREE_CODES - 1);
+  return (enum gimple_code) ((unsigned) tag - NUM_TREE_CODES - 2);
 }
 
 
@@ -958,7 +958,7 @@ lto_tag_to_gimple_code (enum LTO_tags ta
 static inline enum LTO_tags
 lto_tree_code_to_tag (enum tree_code code)
 {
-  return (enum LTO_tags) ((unsigned) code + 1);
+  return (enum LTO_tags) ((unsigned) code + 2);
 }
 
 
@@ -968,7 +968,7 @@ static inline enum tree_code
 lto_tag_to_tree_code (enum LTO_tags tag)
 {
   gcc_assert (lto_tag_is_tree_code_p (tag));
-  return (enum tree_code) ((unsigned) tag - 1);
+  return (enum tree_code) ((unsigned) tag - 2);
 }
 
 /* Check that tag ACTUAL == EXPECTED.  */
Index: gcc/data-streamer.h
===================================================================
--- gcc/data-streamer.h	(revision 199720)
+++ gcc/data-streamer.h	(working copy)
@@ -216,13 +216,7 @@ streamer_write_hwi_in_range (struct lto_
 		       && range < 0x7fffffff);
 
   val -= min;
-  streamer_write_char_stream (obs, val & 255);
-  if (range >= 0xff)
-    streamer_write_char_stream (obs, (val >> 8) & 255);
-  if (range >= 0xffff)
-    streamer_write_char_stream (obs, (val >> 16) & 255);
-  if (range >= 0xffffff)
-    streamer_write_char_stream (obs, (val >> 24) & 255);
+  streamer_write_uhwi_stream (obs, (unsigned HOST_WIDE_INT) val);
 }
 
 /* Input VAL into OBS and verify it is in range MIN...MAX that is supposed
@@ -235,17 +229,11 @@ streamer_read_hwi_in_range (struct lto_i
 				 HOST_WIDE_INT max)
 {
   HOST_WIDE_INT range = max - min;
-  HOST_WIDE_INT val = streamer_read_uchar (ib);
+  unsigned HOST_WIDE_INT uval = streamer_read_uhwi (ib);
 
   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 
-  if (range >= 0xff)
-    val |= ((HOST_WIDE_INT)streamer_read_uchar (ib)) << 8;
-  if (range >= 0xffff)
-    val |= ((HOST_WIDE_INT)streamer_read_uchar (ib)) << 16;
-  if (range >= 0xffffff)
-    val |= ((HOST_WIDE_INT)streamer_read_uchar (ib)) << 24;
-  val += min;
+  HOST_WIDE_INT val = (HOST_WIDE_INT) (uval + (unsigned HOST_WIDE_INT) min);
   if (val < min || val > max)
     lto_value_range_error (purpose, val, min, max);
   return val;