PR opt/14472

	* tree-tailcall.c (process_assignment): Use STRIP_NOPS to
	ignore type conversions that do not inhibit tail calling.
	(find_tail_calls): Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@81855 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 15 insertions, 6 deletions

diff --git a/gcc/tree-tailcall.c b/gcc/tree-tailcall.c
index 65657da250b..9321c93a541 100644
--- a/gcc/tree-tailcall.c
+++ b/gcc/tree-tailcall.c
@@ -72,7 +72,7 @@ Boston, MA 02111-1307, USA.  */
    omit the accumulator.
 
    There are three cases how the function may exit.  The first one is
-   handled in adjust_return_value, the later two in adjust_accumulator_values
+   handled in adjust_return_value, the other two in adjust_accumulator_values
    (the second case is actually a special case of the third one and we
    present it separately just for clarity):
 
@@ -260,10 +260,16 @@ process_assignment (tree ass, tree stmt, block_stmt_iterator call, tree *m,
   tree dest = TREE_OPERAND (ass, 0);
   tree src = TREE_OPERAND (ass, 1);
   enum tree_code code = TREE_CODE (src);
-
-  if (code == SSA_NAME)
+  tree src_var = src;
+
+  /* See if this is a simple copy operation of an SSA name to the function
+     result.  In that case we may have a simple tail call.  Ignore type
+     conversions that can never produce extra code between the function
+     call and the function return.  */
+  STRIP_NOPS (src_var);
+  if (TREE_CODE (src_var) == SSA_NAME)
     {
-      if (src != *ass_var)
+      if (src_var != *ass_var)
 	return false;
 
       *ass_var = dest;
@@ -295,7 +301,7 @@ process_assignment (tree ass, tree stmt, block_stmt_iterator call, tree *m,
   else
     return false;
 
-  switch (TREE_CODE (src))
+  switch (code)
     {
     case PLUS_EXPR:
       /* There should be no previous addition.  TODO -- it should be fairly
@@ -463,12 +469,15 @@ find_tail_calls (basic_block bb, struct tailcall **ret)
 	return;
     }
 
+  /* See if this is a tail call we can handle.  */
   ret_var = TREE_OPERAND (stmt, 0);
   if (ret_var
       && TREE_CODE (ret_var) == MODIFY_EXPR)
     {
+      tree ret_op = TREE_OPERAND (ret_var, 1);
+      STRIP_NOPS (ret_op);
       if (!tail_recursion
-	  && TREE_CODE (TREE_OPERAND (ret_var, 1)) != SSA_NAME)
+	  && TREE_CODE (ret_op) != SSA_NAME)
 	return;
 
       if (!process_assignment (ret_var, stmt, bsi, &m, &a, &ass_var))