PR middle-end/19616

	* tree.h (CALL_EXPR_TAILCALL): Add comment.
	* calls.c (check_sibcall_argument_overlap_1): Revert the change
	to this function from 2004-07-10.
	* tree-tailcall.c (suitable_for_tail_opt_p): Do not consider the
	the current function for tail call optimizations if the address
	of one of it its arguments is taken.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@94265 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 10 insertions, 0 deletions

diff --git a/gcc/tree-tailcall.c b/gcc/tree-tailcall.c
index 5c5e09cce05..a76314bc835 100644
--- a/gcc/tree-tailcall.c
+++ b/gcc/tree-tailcall.c
@@ -159,6 +159,8 @@ suitable_for_tail_opt_p (void)
 static bool
 suitable_for_tail_call_opt_p (void)
 {
+  tree param;
+
   /* alloca (until we have stack slot life analysis) inhibits
      sibling call optimizations, but not tail recursion.  */
   if (current_function_calls_alloca)
@@ -176,6 +178,14 @@ suitable_for_tail_call_opt_p (void)
   if (current_function_calls_setjmp)
     return false;
 
+  /* ??? It is OK if the argument of a function is taken in some cases,
+     but not in all cases.  See PR15387 and PR19616.  Revisit for 4.1.  */
+  for (param = DECL_ARGUMENTS (current_function_decl);
+       param;
+       param = TREE_CHAIN (param))
+    if (TREE_ADDRESSABLE (param))
+      return false;
+
   return true;
 }