devirt-13.C: New testcase.

	* g++.dg/ipa/devirt-13.C: New testcase.
	* g++.dg/ipa/devirt-14.C: New testcase.
	* cgraphunit.c (analyze_functions): Do basic devirtualization;
	do not walk base classes of anonymous types.

From-SVN: r201942

5 files changed, 133 insertions, 20 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 07d70ee..76609fb 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2013-08-23  Jan Hubicka  <jh@suse.cz>
+
+	* cgraphunit.c (analyze_functions): Do basic devirtualization;
+	do not walk base classes of anonymous types.
+
 2013-08-23  Kaz Kojima  <kkojima@gcc.gnu.org>
 
 	PR rtl-optimization/58220
diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index 0b839b0..db3db4b 100644
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -922,26 +922,73 @@ analyze_functions (void)
 		   enqueue_node ((symtab_node)edge->callee);
 	      if (optimize && flag_devirtualize)
 		{
-	          for (edge = cnode->indirect_calls; edge; edge = edge->next_callee)
-		    if (edge->indirect_info->polymorphic)
-		      {
-			unsigned int i;
-			void *cache_token;
-			vec <cgraph_node *>targets
-			  = possible_polymorphic_call_targets
-			      (edge, NULL, &cache_token);
-
-			if (!pointer_set_insert (reachable_call_targets,
-						 cache_token))
-			  {
-			    if (cgraph_dump_file)
-			      dump_possible_polymorphic_call_targets 
-				(cgraph_dump_file, edge);
-
-			    for (i = 0; i < targets.length(); i++)
-			      enqueue_node ((symtab_node) targets[i]);
-			  }
-		      }
+		  struct cgraph_edge *next;
+	          for (edge = cnode->indirect_calls; edge; edge = next)
+		    {
+		      next = edge->next_callee;
+		      if (edge->indirect_info->polymorphic)
+			{
+			  unsigned int i;
+			  void *cache_token;
+			  bool final;
+			  vec <cgraph_node *>targets
+			    = possible_polymorphic_call_targets
+				(edge, &final, &cache_token);
+
+			  if (!pointer_set_insert (reachable_call_targets,
+						   cache_token))
+			    {
+			      if (cgraph_dump_file)
+				dump_possible_polymorphic_call_targets 
+				  (cgraph_dump_file, edge);
+
+			      for (i = 0; i < targets.length(); i++)
+				{
+				  /* Do not bother to mark virtual methods in anonymous namespace;
+				     either we will find use of virtual table defining it, or it is
+				     unused.  */
+				  if (targets[i]->symbol.definition
+				      && TREE_CODE
+					  (TREE_TYPE (targets[i]->symbol.decl))
+					   == METHOD_TYPE
+				      && !type_in_anonymous_namespace_p
+					   (method_class_type
+					     (TREE_TYPE (targets[i]->symbol.decl))))
+				  enqueue_node ((symtab_node) targets[i]);
+				}
+			    }
+
+			  /* Very trivial devirtualization; when the type is
+			     final or anonymous (so we know all its derivation)
+			     and there is only one possible virtual call target,
+			     make the edge direct.  */
+			  if (final)
+			    {
+			      gcc_assert (targets.length());
+			      if (targets.length() == 1)
+				{
+				  if (cgraph_dump_file)
+				    {
+				      fprintf (cgraph_dump_file,
+					       "Devirtualizing call: ");
+				      print_gimple_stmt (cgraph_dump_file,
+							 edge->call_stmt, 0,
+							 TDF_SLIM);
+				    }
+				  cgraph_make_edge_direct (edge, targets[0]);
+				  cgraph_redirect_edge_call_stmt_to_callee (edge);
+				  if (cgraph_dump_file)
+				    {
+				      fprintf (cgraph_dump_file,
+					       "Devirtualized as: ");
+				      print_gimple_stmt (cgraph_dump_file,
+							 edge->call_stmt, 0,
+							 TDF_SLIM);
+				    }
+				}
+			    }
+			}
+		    }
 		}
 
 	      /* If decl is a clone of an abstract function,
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index db1c984..47196da 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2013-08-23  Jan Hubicka  <jh@suse.cz>
+
+	* g++.dg/ipa/devirt-13.C: New testcase.
+	* g++.dg/ipa/devirt-14.C: New testcase.
+
 2013-08-23  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/58218
diff --git a/gcc/testsuite/g++.dg/ipa/devirt-13.C b/gcc/testsuite/g++.dg/ipa/devirt-13.C
new file mode 100644
index 0000000..13fbaee
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ipa/devirt-13.C
@@ -0,0 +1,22 @@
+/* { dg-do run } */
+/* Call to foo should be devirtualized because there are no derived types of A.  */
+/* { dg-options "-O2 -fdump-ipa-cgraph -fdump-tree-ssa"  } */
+namespace {
+class A {
+public:
+  virtual int foo(void)
+{
+  return 0;
+}
+};
+}
+class A a, *b=&a;
+main()
+{
+  return b->foo();
+}
+
+/* { dg-final { scan-ipa-dump "Devirtualizing call"  "cgraph"  } } */
+/* { dg-final { scan-tree-dump-times "OBJ_TYPE_REF" 0 "ssa"} } */
+/* { dg-final { cleanup-ipa-dump "cgraph" } } */
+/* { dg-final { cleanup-tree-dump "ssa" } } */
diff --git a/gcc/testsuite/g++.dg/ipa/devirt-14.C b/gcc/testsuite/g++.dg/ipa/devirt-14.C
new file mode 100644
index 0000000..1a87c25
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ipa/devirt-14.C
@@ -0,0 +1,34 @@
+/* No devirtualization happens here, but A::foo should not end up as reachable
+   because the constructor of A is unreachable and therefore the virtual
+   method table referring to A::foo is optimized out.  */
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-ssa"  } */
+class B {
+public:
+  virtual int foo(void)
+{
+  return 0;
+}
+};
+namespace {
+class A : public B {
+public:
+  virtual int foo(void)
+{
+  return 1;
+}
+};
+}
+class B a, *b=&a;
+main()
+{
+  if (0)
+    {
+    class A a;
+    a.foo();
+    }
+  return b->foo();
+}
+
+/* { dg-final { scan-tree-dump-nop "A::foo" 0 "ssa"} } */
+/* { dg-final { cleanup-tree-dump "ssa" } } */