Simplify CFG copying tables

This simplifies the maps between original and new basic blocks and
loops as used for CFG copying.  Instead of using a pointer hash
table to allocated mapping entries use a hash_map with int_hash,
removing the indirection and code duplication.  We can use -1 and
-2 as empty/deleted values as those are not valid basic-block
indices or loop numbers.

2020-10-21  Richard Biener  <rguenther@suse.de>

	* cfg.c (htab_bb_copy_original_entry): Remove.
	(bb_copy_hasher): Likewise.
	(bb_original, bb_copy, loop_copy): Use
	hash_map<int_hash<int, -1, -2>, int>.
	(original_copy_bb_pool): Remove.
	(initialize_original_copy_tables): Adjust.
	(reset_original_copy_tables): Likewise.
	(free_original_copy_tables): Likewise.
	(original_copy_tables_initialized_p): Likewise.
	(copy_original_table_clear): Simplify.
	(copy_original_table_set): Likewise.
	(get_bb_original): Likewise.
	(get_bb_copy): Likewise.
	(get_loop_copy): Likewise.

1 files changed, 23 insertions, 91 deletions

diff --git a/gcc/cfg.c b/gcc/cfg.c
index 270a48f..d82324f 100644
--- a/gcc/cfg.c
+++ b/gcc/cfg.c
@@ -959,55 +959,23 @@ scale_bbs_frequencies (basic_block *bbs, int nbbs,
     bbs[i]->count = bbs[i]->count.apply_probability (p);
 }
 
-/* Helper types for hash tables.  */
-
-struct htab_bb_copy_original_entry
-{
-  /* Block we are attaching info to.  */
-  int index1;
-  /* Index of original or copy (depending on the hashtable) */
-  int index2;
-};
-
-struct bb_copy_hasher : nofree_ptr_hash <htab_bb_copy_original_entry>
-{
-  static inline hashval_t hash (const htab_bb_copy_original_entry *);
-  static inline bool equal (const htab_bb_copy_original_entry *existing,
-			    const htab_bb_copy_original_entry * candidate);
-};
-
-inline hashval_t
-bb_copy_hasher::hash (const htab_bb_copy_original_entry *data)
-{
-  return data->index1;
-}
-
-inline bool
-bb_copy_hasher::equal (const htab_bb_copy_original_entry *data,
-		       const htab_bb_copy_original_entry *data2)
-{
-  return data->index1 == data2->index1;
-}
-
 /* Data structures used to maintain mapping between basic blocks and
    copies.  */
-static hash_table<bb_copy_hasher> *bb_original;
-static hash_table<bb_copy_hasher> *bb_copy;
+typedef hash_map<int_hash<int, -1, -2>, int> copy_map_t;
+static copy_map_t *bb_original;
+static copy_map_t *bb_copy;
 
 /* And between loops and copies.  */
-static hash_table<bb_copy_hasher> *loop_copy;
-static object_allocator<htab_bb_copy_original_entry> *original_copy_bb_pool;
+static copy_map_t *loop_copy;
 
 /* Initialize the data structures to maintain mapping between blocks
    and its copies.  */
 void
 initialize_original_copy_tables (void)
 {
-  original_copy_bb_pool = new object_allocator<htab_bb_copy_original_entry>
-    ("original_copy");
-  bb_original = new hash_table<bb_copy_hasher> (10);
-  bb_copy = new hash_table<bb_copy_hasher> (10);
-  loop_copy = new hash_table<bb_copy_hasher> (10);
+  bb_original = new copy_map_t (10);
+  bb_copy = new copy_map_t (10);
+  loop_copy = new copy_map_t (10);
 }
 
 /* Reset the data structures to maintain mapping between blocks and
@@ -1016,7 +984,6 @@ initialize_original_copy_tables (void)
 void
 reset_original_copy_tables (void)
 {
-  gcc_assert (original_copy_bb_pool);
   bb_original->empty ();
   bb_copy->empty ();
   loop_copy->empty ();
@@ -1027,15 +994,12 @@ reset_original_copy_tables (void)
 void
 free_original_copy_tables (void)
 {
-  gcc_assert (original_copy_bb_pool);
   delete bb_copy;
   bb_copy = NULL;
   delete bb_original;
   bb_original = NULL;
   delete loop_copy;
   loop_copy = NULL;
-  delete original_copy_bb_pool;
-  original_copy_bb_pool = NULL;
 }
 
 /* Return true iff we have had a call to initialize_original_copy_tables
@@ -1044,51 +1008,31 @@ free_original_copy_tables (void)
 bool
 original_copy_tables_initialized_p (void)
 {
-  return original_copy_bb_pool != NULL;
+  return bb_copy != NULL;
 }
 
 /* Removes the value associated with OBJ from table TAB.  */
 
 static void
-copy_original_table_clear (hash_table<bb_copy_hasher> *tab, unsigned obj)
+copy_original_table_clear (copy_map_t *tab, unsigned obj)
 {
-  htab_bb_copy_original_entry **slot;
-  struct htab_bb_copy_original_entry key, *elt;
-
-  if (!original_copy_bb_pool)
+  if (!original_copy_tables_initialized_p ())
     return;
 
-  key.index1 = obj;
-  slot = tab->find_slot (&key, NO_INSERT);
-  if (!slot)
-    return;
-
-  elt = *slot;
-  tab->clear_slot (slot);
-  original_copy_bb_pool->remove (elt);
+  tab->remove (obj);
 }
 
 /* Sets the value associated with OBJ in table TAB to VAL.
    Do nothing when data structures are not initialized.  */
 
 static void
-copy_original_table_set (hash_table<bb_copy_hasher> *tab,
+copy_original_table_set (copy_map_t *tab,
 			 unsigned obj, unsigned val)
 {
-  struct htab_bb_copy_original_entry **slot;
-  struct htab_bb_copy_original_entry key;
-
-  if (!original_copy_bb_pool)
+  if (!original_copy_tables_initialized_p ())
     return;
 
-  key.index1 = obj;
-  slot = tab->find_slot (&key, INSERT);
-  if (!*slot)
-    {
-      *slot = original_copy_bb_pool->allocate ();
-      (*slot)->index1 = obj;
-    }
-  (*slot)->index2 = val;
+  tab->put (obj, val);
 }
 
 /* Set original for basic block.  Do nothing when data structures are not
@@ -1103,15 +1047,11 @@ set_bb_original (basic_block bb, basic_block original)
 basic_block
 get_bb_original (basic_block bb)
 {
-  struct htab_bb_copy_original_entry *entry;
-  struct htab_bb_copy_original_entry key;
-
-  gcc_assert (original_copy_bb_pool);
+  gcc_assert (original_copy_tables_initialized_p ());
 
-  key.index1 = bb->index;
-  entry = bb_original->find (&key);
+  int *entry = bb_original->get (bb->index);
   if (entry)
-    return BASIC_BLOCK_FOR_FN (cfun, entry->index2);
+    return BASIC_BLOCK_FOR_FN (cfun, *entry);
   else
     return NULL;
 }
@@ -1128,15 +1068,11 @@ set_bb_copy (basic_block bb, basic_block copy)
 basic_block
 get_bb_copy (basic_block bb)
 {
-  struct htab_bb_copy_original_entry *entry;
-  struct htab_bb_copy_original_entry key;
+  gcc_assert (original_copy_tables_initialized_p ());
 
-  gcc_assert (original_copy_bb_pool);
-
-  key.index1 = bb->index;
-  entry = bb_copy->find (&key);
+  int *entry = bb_copy->get (bb->index);
   if (entry)
-    return BASIC_BLOCK_FOR_FN (cfun, entry->index2);
+    return BASIC_BLOCK_FOR_FN (cfun, *entry);
   else
     return NULL;
 }
@@ -1158,15 +1094,11 @@ set_loop_copy (class loop *loop, class loop *copy)
 class loop *
 get_loop_copy (class loop *loop)
 {
-  struct htab_bb_copy_original_entry *entry;
-  struct htab_bb_copy_original_entry key;
-
-  gcc_assert (original_copy_bb_pool);
+  gcc_assert (original_copy_tables_initialized_p ());
 
-  key.index1 = loop->num;
-  entry = loop_copy->find (&key);
+  int *entry = loop_copy->get (loop->num);
   if (entry)
-    return get_loop (cfun, entry->index2);
+    return get_loop (cfun, *entry);
   else
     return NULL;
 }