[PATCH] Speed-up IPA ICF by enhanced hash values

[Martin LiÅka <mliska at suse dot cz>]

Hi.

Following patch improves performance by adding hash values of references that are not
candidates for IPA ICF. Tested on x86_64-linux-pc w/o any new regression observed.

Ready for trunk?
Thanks,
Martin

>From 6c04cc4283d08a8aa9829574dd91579a918cb508 Mon Sep 17 00:00:00 2001
From: marxin <marxin.liska@gmail.com>
Date: Sun, 15 Mar 2015 19:21:39 -0500
Subject: [PATCH] IPA ICF: include hash values of references.

gcc/ChangeLog:

2015-03-15  Martin Liska  <mliska@suse.cz>

	* ipa-icf.c (sem_item::update_hash_by_addr_refs): New function.
	(sem_item::update_hash_by_local_refs): Likewise.
	(sem_variable::get_hash): Empty line is fixed.
	(sem_item_optimizer::execute): Include adding of hash references.
	(sem_item_optimizer::update_hash_by_addr_refs): New function.
	(sem_item_optimizer::build_hash_based_classes): Use local hash.
	* ipa-icf.h (sem_item::update_hash_by_addr_refs): New function.
	(sem_item::update_hash_by_local_refs): Likewise.
---
 gcc/ipa-icf.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 gcc/ipa-icf.h | 18 ++++++++++++-
 2 files changed, 97 insertions(+), 5 deletions(-)

diff --git a/gcc/ipa-icf.c b/gcc/ipa-icf.c
index f68d23c..b8e3aa4 100644
--- a/gcc/ipa-icf.c
+++ b/gcc/ipa-icf.c
@@ -557,6 +557,69 @@ sem_function::equals_wpa (sem_item *item,
   return true;
 }
 
+/* Update hash by address sensitive references.  */
+
+void
+sem_item::update_hash_by_addr_refs (hash_map <symtab_node *,
+				    sem_item *> &m_symtab_node_map)
+{
+  if (is_a <varpool_node *> (node) && DECL_VIRTUAL_P (node->decl))
+    return;
+
+  ipa_ref* ref;
+  inchash::hash hstate (hash);
+  for (unsigned i = 0; i < node->num_references (); i++)
+    {
+      ref = node->iterate_reference (i, ref);
+      if (ref->address_matters_p ())
+	hstate.add_ptr (ref->referred->ultimate_alias_target ());
+    }
+
+  if (is_a <cgraph_node *> (node))
+    {
+      for (cgraph_edge *e = dyn_cast <cgraph_node *> (node)->callers; e;
+	   e = e->next_caller)
+	{
+	  sem_item **result = m_symtab_node_map.get (e->callee);
+	  if (!result)
+	    hstate.add_ptr (e->callee->ultimate_alias_target ());
+	}
+    }
+
+  hash = hstate.end ();
+}
+
+/* Update hash by computed local hash values taken from different
+   semantic items.  */
+
+void
+sem_item::update_hash_by_local_refs (hash_map <symtab_node *,
+				     sem_item *> &m_symtab_node_map)
+{
+  inchash::hash state (hash);
+  for (unsigned j = 0; j < node->num_references (); j++)
+    {
+      ipa_ref *ref;
+      ref = node->iterate_reference (j, ref);
+      sem_item **result = m_symtab_node_map.get (ref->referring);
+      if (result)
+	state.merge_hash ((*result)->hash);
+    }
+
+  if (type == FUNC)
+    {
+      for (cgraph_edge *e = dyn_cast <cgraph_node *> (node)->callees; e;
+	   e = e->next_callee)
+	{
+	  sem_item **result = m_symtab_node_map.get (e->caller);
+	  if (result)
+	    state.merge_hash ((*result)->hash);
+	}
+    }
+
+  global_hash = state.end ();
+}
+
 /* Returns true if the item equals to ITEM given as argument.  */
 
 bool
@@ -1742,8 +1805,8 @@ hashval_t
 sem_variable::get_hash (void)
 {
   if (hash)
-
     return hash;
+
   /* All WPA streamed in symbols should have their hashes computed at compile
      time.  At this point, the constructor may not be in memory at all.
      DECL_INITIAL (decl) would be error_mark_node in that case.  */
@@ -2202,6 +2265,8 @@ sem_item_optimizer::execute (void)
   filter_removed_items ();
   unregister_hooks ();
 
+  build_graph ();
+  update_hash_by_addr_refs ();
   build_hash_based_classes ();
 
   if (dump_file)
@@ -2211,8 +2276,6 @@ sem_item_optimizer::execute (void)
   for (unsigned int i = 0; i < m_items.length(); i++)
     m_items[i]->init_wpa ();
 
-  build_graph ();
-
   subdivide_classes_by_equality (true);
 
   if (dump_file)
@@ -2301,6 +2364,19 @@ sem_item_optimizer::add_item_to_class (congruence_class *cls, sem_item *item)
   item->cls = cls;
 }
 
+void
+sem_item_optimizer::update_hash_by_addr_refs ()
+{
+  for (unsigned i = 0; i < m_items.length (); i++)
+    m_items[i]->update_hash_by_addr_refs (m_symtab_node_map);
+
+  for (unsigned i = 0; i < m_items.length (); i++)
+    m_items[i]->update_hash_by_local_refs (m_symtab_node_map);
+
+  for (unsigned i = 0; i < m_items.length (); i++)
+    m_items[i]->hash = m_items[i]->global_hash;
+}
+
 /* Congruence classes are built by hash value.  */
 
 void
@@ -2310,7 +2386,7 @@ sem_item_optimizer::build_hash_based_classes (void)
     {
       sem_item *item = m_items[i];
 
-      congruence_class_group *group = get_group_by_hash (item->get_hash (),
+      congruence_class_group *group = get_group_by_hash (item->hash,
 				      item->type);
 
       if (!group->classes.length ())
diff --git a/gcc/ipa-icf.h b/gcc/ipa-icf.h
index 8245b54..ad502a7 100644
--- a/gcc/ipa-icf.h
+++ b/gcc/ipa-icf.h
@@ -189,6 +189,15 @@ public:
   /* Dump symbol to FILE.  */
   virtual void dump_to_file (FILE *file) = 0;
 
+  /* Update hash by address sensitive references.  */
+  void update_hash_by_addr_refs (hash_map <symtab_node *,
+				 sem_item *> &m_symtab_node_map);
+
+  /* Update hash by computed local hash values taken from different
+     semantic items.  */
+  void update_hash_by_local_refs (hash_map <symtab_node *,
+				  sem_item *> &m_symtab_node_map);
+
   /* Return base tree that can be used for compatible_types_p and
      contains_polymorphic_type_p comparison.  */
   static bool get_base_types (tree *t1, tree *t2);
@@ -226,9 +235,13 @@ public:
   /* A set with symbol table references.  */
   hash_set <symtab_node *> refs_set;
 
+  /* Hash of item.  */
+  hashval_t hash;
+
+  /* Temporary hash used where hash values of references are added.  */
+  hashval_t global_hash;
 protected:
   /* Cached, once calculated hash for the item.  */
-  hashval_t hash;
 
   /* Accumulate to HSTATE a hash of constructor expression EXP.  */
   static void add_expr (const_tree exp, inchash::hash &hstate);
@@ -494,6 +507,9 @@ public:
 
 private:
 
+  /* Update hash of symbol by address memory references.  */
+  void update_hash_by_addr_refs ();
+
   /* Congruence classes are built by hash value.  */
   void build_hash_based_classes (void);
 
-- 
2.1.2