2010-04-16 Richard Guenther <rguenther@suse.de>

	PR tree-optimization/43572
	* tree-ssa-alias.h (call_may_clobber_ref_p): Declare.
	* tree-ssa-alias.c (call_may_clobber_ref_p): Export.
	* tree-flow.h (is_call_clobbered): Remove.
	* tree-flow-inline.h (is_call_clobbered): Likewise.
	* tree-dfa.c (dump_variable): Do not dump call clobber state.
	* tree-nrv.c (dest_safe_for_nrv_p): Use the alias oracle.
	(execute_return_slot_opt): Adjust.
	* tree-tailcall.c (suitable_for_tail_opt_p): Remove
	check for call clobbered vars here.
	(find_tail_calls): Move tailcall verification to the
	proper place.

	* gcc.dg/tree-ssa/tailcall-5.c: New testcase.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@158418 138bc75d-0d04-0410-961f-82ee72b054a4

10 files changed, 57 insertions, 58 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f06b1baa0fc..bd2dc3c56bf 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,18 @@
+2010-04-16  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/43572
+	* tree-ssa-alias.h (call_may_clobber_ref_p): Declare.
+	* tree-ssa-alias.c (call_may_clobber_ref_p): Export.
+	* tree-flow.h (is_call_clobbered): Remove.
+	* tree-flow-inline.h (is_call_clobbered): Likewise.
+	* tree-dfa.c (dump_variable): Do not dump call clobber state.
+	* tree-nrv.c (dest_safe_for_nrv_p): Use the alias oracle.
+	(execute_return_slot_opt): Adjust.
+	* tree-tailcall.c (suitable_for_tail_opt_p): Remove
+	check for call clobbered vars here.
+	(find_tail_calls): Move tailcall verification to the
+	proper place.
+
 2010-04-16  Diego Novillo  <dnovillo@google.com>
 
 	* doc/invoke.texi: Explain how are unrecognized -Wno- warnings
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 589e80f89c0..b58bb508e88 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2010-04-16  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/43572
+	* gcc.dg/tree-ssa/tailcall-5.c: New testcase.
+
 2010-04-16  Olivier Hainque  <hainque@adacore.com>
 
 	* gnat.dg/specs/discr_private.ads: New test.
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/tailcall-5.c b/gcc/testsuite/gcc.dg/tree-ssa/tailcall-5.c
new file mode 100644
index 00000000000..7aa433ecf7a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/tailcall-5.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-tailc" } */
+
+void
+set_integer (void *dest, int value, int length)
+{
+  int tmp = value;
+  __builtin_memcpy (dest, (void *) &tmp, length);
+}
+
+/* { dg-final { scan-tree-dump-not "tail call" "tailc" } } */
+/* { dg-final { cleanup-tree-dump "tailc" } } */
diff --git a/gcc/tree-dfa.c b/gcc/tree-dfa.c
index a8415b5a825..5475d79254b 100644
--- a/gcc/tree-dfa.c
+++ b/gcc/tree-dfa.c
@@ -284,9 +284,6 @@ dump_variable (FILE *file, tree var)
   if (TREE_THIS_VOLATILE (var))
     fprintf (file, ", is volatile");
 
-  if (is_call_clobbered (var))
-    fprintf (file, ", call clobbered");
-
   if (ann && ann->noalias_state == NO_ALIAS)
     fprintf (file, ", NO_ALIAS (does not alias other NO_ALIAS symbols)");
   else if (ann && ann->noalias_state == NO_ALIAS_GLOBAL)
diff --git a/gcc/tree-flow-inline.h b/gcc/tree-flow-inline.h
index 2430f0355f7..f7609ea7911 100644
--- a/gcc/tree-flow-inline.h
+++ b/gcc/tree-flow-inline.h
@@ -624,15 +624,6 @@ loop_containing_stmt (gimple stmt)
 }
 
 
-/* Return true if VAR is clobbered by function calls.  */
-static inline bool
-is_call_clobbered (const_tree var)
-{
-  return (is_global_var (var)
-	  || (may_be_aliased (var)
-	      && pt_solution_includes (&cfun->gimple_df->escaped, var)));
-}
-
 /*  -----------------------------------------------------------------------  */
 
 /* The following set of routines are used to iterator over various type of
diff --git a/gcc/tree-flow.h b/gcc/tree-flow.h
index fda7a86f2d0..8f9ab5de0f1 100644
--- a/gcc/tree-flow.h
+++ b/gcc/tree-flow.h
@@ -774,7 +774,6 @@ extern enum move_pos movement_possibility (gimple);
 char *get_lsm_tmp_name (tree, unsigned);
 
 /* In tree-flow-inline.h  */
-static inline bool is_call_clobbered (const_tree);
 static inline void set_is_used (tree);
 static inline bool unmodifiable_var_p (const_tree);
 static inline bool ref_contains_array_ref (const_tree);
diff --git a/gcc/tree-nrv.c b/gcc/tree-nrv.c
index b85c5a76c67..c2e49d32c17 100644
--- a/gcc/tree-nrv.c
+++ b/gcc/tree-nrv.c
@@ -291,23 +291,21 @@ struct gimple_opt_pass pass_nrv =
    optimization, where DEST is expected to be the LHS of a modify
    expression where the RHS is a function returning an aggregate.
 
-   We search for a base VAR_DECL and look to see if it is call clobbered.
-   Note that we could do better, for example, by
-   attempting to doing points-to analysis on INDIRECT_REFs.  */
+   DEST is available if it is not clobbered by the call.  */
 
 static bool
-dest_safe_for_nrv_p (tree dest)
+dest_safe_for_nrv_p (gimple call)
 {
-  while (handled_component_p (dest))
-    dest = TREE_OPERAND (dest, 0);
+  tree dest = gimple_call_lhs (call);
 
-  if (! SSA_VAR_P (dest))
+  dest = get_base_address (dest);
+  if (! dest)
     return false;
 
   if (TREE_CODE (dest) == SSA_NAME)
-    dest = SSA_NAME_VAR (dest);
+    return true;
 
-  if (is_call_clobbered (dest))
+  if (call_may_clobber_ref_p (call, dest))
     return false;
 
   return true;
@@ -346,8 +344,8 @@ execute_return_slot_opt (void)
 	     )
 	    {
 	      /* Check if the location being assigned to is
-	         call-clobbered.  */
-	      slot_opt_p = dest_safe_for_nrv_p (gimple_call_lhs (stmt));
+	         clobbered by the call.  */
+	      slot_opt_p = dest_safe_for_nrv_p (stmt);
 	      gimple_call_set_return_slot_opt (stmt, slot_opt_p);
 	    }
 	}
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 8b1fdc37556..67c669e8b4b 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -1339,7 +1339,10 @@ call_may_clobber_ref_p_1 (gimple call, ao_ref *ref)
   return true;
 }
 
-static bool ATTRIBUTE_UNUSED
+/* If the call in statement CALL may clobber the memory reference REF
+   return true, otherwise return false.  */
+
+bool
 call_may_clobber_ref_p (gimple call, tree ref)
 {
   bool res;
diff --git a/gcc/tree-ssa-alias.h b/gcc/tree-ssa-alias.h
index 147f3688434..a2b532747c6 100644
--- a/gcc/tree-ssa-alias.h
+++ b/gcc/tree-ssa-alias.h
@@ -104,6 +104,7 @@ extern bool refs_output_dependent_p (tree, tree);
 extern bool ref_maybe_used_by_stmt_p (gimple, tree);
 extern bool stmt_may_clobber_ref_p (gimple, tree);
 extern bool stmt_may_clobber_ref_p_1 (gimple, ao_ref *);
+extern bool call_may_clobber_ref_p (gimple, tree);
 extern tree get_continuation_for_phi (gimple, ao_ref *, bitmap *);
 extern void *walk_non_aliased_vuses (ao_ref *, tree,
 				     void *(*)(ao_ref *, tree, void *),
diff --git a/gcc/tree-tailcall.c b/gcc/tree-tailcall.c
index e0d3f4844e9..ca3dffadc75 100644
--- a/gcc/tree-tailcall.c
+++ b/gcc/tree-tailcall.c
@@ -130,32 +130,9 @@ static void find_tail_calls (basic_block, struct tailcall **);
 static bool
 suitable_for_tail_opt_p (void)
 {
-  referenced_var_iterator rvi;
-  tree var;
-
   if (cfun->stdarg)
     return false;
 
-  /* No local variable nor structure field should escape to callees.  */
-  FOR_EACH_REFERENCED_VAR (var, rvi)
-    {
-      if (!is_global_var (var)
-	  /* ???  We do not have a suitable predicate for escaping to
-	     callees.  With IPA-PTA the following might be incorrect.
-	     We want to catch
-	       foo {
-	         int i;
-		 bar (&i);
-		 foo ();
-	       }
-	     where bar might store &i somewhere and in the next
-	     recursion should not be able to tell if it got the
-	     same (with tail-recursion applied) or a different
-	     address.  */
-	  && is_call_clobbered (var))
-	return false;
-    }
-
   return true;
 }
 /* Returns false when the function is not suitable for tail call optimization
@@ -387,6 +364,8 @@ find_tail_calls (basic_block bb, struct tailcall **ret)
   tree m, a;
   basic_block abb;
   size_t idx;
+  tree var;
+  referenced_var_iterator rvi;
 
   if (!single_succ_p (bb))
     return;
@@ -442,8 +421,7 @@ find_tail_calls (basic_block bb, struct tailcall **ret)
   func = gimple_call_fndecl (call);
   if (func == current_function_decl)
     {
-      tree arg, var;
-      referenced_var_iterator rvi;
+      tree arg;
 
       for (param = DECL_ARGUMENTS (func), idx = 0;
 	   param && idx < gimple_call_num_args (call);
@@ -474,15 +452,15 @@ find_tail_calls (basic_block bb, struct tailcall **ret)
 	}
       if (idx == gimple_call_num_args (call) && !param)
 	tail_recursion = true;
+    }
 
-      /* Make sure the tail invocation of this function does not refer
-	 to local variables.  */
-      FOR_EACH_REFERENCED_VAR (var, rvi)
-	{
-	  if (!is_global_var (var)
-	      && ref_maybe_used_by_stmt_p (call, var))
-	    return;
-	}
+  /* Make sure the tail invocation of this function does not refer
+     to local variables.  */
+  FOR_EACH_REFERENCED_VAR (var, rvi)
+    {
+      if (!is_global_var (var)
+	  && ref_maybe_used_by_stmt_p (call, var))
+	return;
     }
 
   /* Now check the statements after the call.  None of them has virtual