2017-08-23  Nathan Sidwell  <nathan@acm.org>

	* cp-tree.h (maybe_version_functions): Declare.
	* decl.c (decls_match): Break function versioning check to
	separate function.  Call it.
	(maybe_version_functions): Broken out of decls_match.
	* class.c (add_method): Use maybe_version_functions.

Index: class.c
===================================================================
--- class.c	(revision 251313)
+++ class.c	(working copy)
@@ -1154,33 +1154,11 @@ add_method (tree type, tree method, bool
 			      TREE_TYPE (method_type)))
           && equivalently_constrained (fn, method))
 	{
-	  /* For function versions, their parms and types match
-	     but they are not duplicates.  Record function versions
-	     as and when they are found.  extern "C" functions are
-	     not treated as versions.  */
+	  /* If these are versions of the same function, process and
+	     move on.  */
 	  if (TREE_CODE (fn) == FUNCTION_DECL
-	      && TREE_CODE (method) == FUNCTION_DECL
-	      && !DECL_EXTERN_C_P (fn)
-	      && !DECL_EXTERN_C_P (method)
-	      && targetm.target_option.function_versions (fn, method))
- 	    {
-	      /* Mark functions as versions if necessary.  Modify the mangled
-		 decl name if necessary.  */
-	      if (!DECL_FUNCTION_VERSIONED (fn))
-		{
-		  DECL_FUNCTION_VERSIONED (fn) = 1;
-		  if (DECL_ASSEMBLER_NAME_SET_P (fn))
-		    mangle_decl (fn);
-		}
-	      if (!DECL_FUNCTION_VERSIONED (method))
-		{
-		  DECL_FUNCTION_VERSIONED (method) = 1;
-		  if (DECL_ASSEMBLER_NAME_SET_P (method))
-		    mangle_decl (method);
-		}
-	      cgraph_node::record_function_versions (fn, method);
-	      continue;
-	    }
+	      && maybe_version_functions (method, fn))
+	    continue;
 
 	  if (DECL_INHERITED_CTOR (method))
 	    {
Index: cp-tree.h
===================================================================
--- cp-tree.h	(revision 251313)
+++ cp-tree.h	(working copy)
@@ -6071,6 +6071,7 @@ extern void push_switch				(tree);
 extern void pop_switch				(void);
 extern tree make_lambda_name			(void);
 extern int decls_match				(tree, tree);
+extern bool maybe_version_functions		(tree, tree);
 extern tree duplicate_decls			(tree, tree, bool);
 extern tree declare_local_label			(tree);
 extern tree define_label			(location_t, tree);
Index: decl.c
===================================================================
--- decl.c	(revision 251313)
+++ decl.c	(working copy)
@@ -1088,28 +1088,8 @@ decls_match (tree newdecl, tree olddecl)
       if (types_match
 	  && !DECL_EXTERN_C_P (newdecl)
 	  && !DECL_EXTERN_C_P (olddecl)
-	  && targetm.target_option.function_versions (newdecl, olddecl))
-	{
-	  /* Mark functions as versions if necessary.  Modify the mangled decl
-	     name if necessary.  */
-	  if (DECL_FUNCTION_VERSIONED (newdecl)
-	      && DECL_FUNCTION_VERSIONED (olddecl))
-	    return 0;
-	  if (!DECL_FUNCTION_VERSIONED (newdecl))
-	    {
-	      DECL_FUNCTION_VERSIONED (newdecl) = 1;
-	      if (DECL_ASSEMBLER_NAME_SET_P (newdecl))
-	        mangle_decl (newdecl);
-	    }
-	  if (!DECL_FUNCTION_VERSIONED (olddecl))
-	    {
-	      DECL_FUNCTION_VERSIONED (olddecl) = 1;
-	      if (DECL_ASSEMBLER_NAME_SET_P (olddecl))
-	       mangle_decl (olddecl);
-	    }
-	  cgraph_node::record_function_versions (olddecl, newdecl);
-	  return 0;
-	}
+	  && maybe_version_functions (newdecl, olddecl))
+	return 0;
     }
   else if (TREE_CODE (newdecl) == TEMPLATE_DECL)
     {
@@ -1165,6 +1145,40 @@ decls_match (tree newdecl, tree olddecl)
   return types_match;
 }
 
+/* NEWDECL and OLDDECL have identical signatures.  If they are
+   different versions adjust them and return true.  */
+
+bool
+maybe_version_functions (tree newdecl, tree olddecl)
+{
+  if (!targetm.target_option.function_versions (newdecl, olddecl))
+    return false;
+
+  bool record = false;
+
+  if (!DECL_FUNCTION_VERSIONED (olddecl))
+    {
+      record = true;
+      DECL_FUNCTION_VERSIONED (olddecl) = 1;
+      if (DECL_ASSEMBLER_NAME_SET_P (olddecl))
+	mangle_decl (olddecl);
+    }
+
+  if (!DECL_FUNCTION_VERSIONED (newdecl))
+    {
+      record = true;
+      DECL_FUNCTION_VERSIONED (newdecl) = 1;
+      if (DECL_ASSEMBLER_NAME_SET_P (newdecl))
+	mangle_decl (newdecl);
+    }
+
+  /* Only record if at least one was not already versions.  */
+  if (record)
+    cgraph_node::record_function_versions (olddecl, newdecl);
+
+  return true;
+}
+
 /* If NEWDECL is `static' and an `extern' was seen previously,
    warn about it.  OLDDECL is the previous declaration.