------- Comment #2 from dferbas at etech dot cz 2009-09-22 22:39 -------
We tried to modify the m68k variant of sibcall fn. But we have a problem with
compilation. Is there anyone who can test if following is OK ?
/* Implement TARGET_FUNCTION_OK_FOR_SIBCALL_P. We cannot use sibcalls
for nested functions because we use the static chain register for
indirect calls. */
static bool
m68k_ok_for_sibcall_p (tree decl, tree exp)
{
tree func;
rtx a, b;
enum m68k_function_kind kind;
if (TREE_OPERAND (exp, 2))
return false;
/* --- incorporated from x386 ---
* This addresses issue when 1 fn returns a pointer in an address
register
* it is casted and the other fn returns a value in data register. */
if (decl)
func = decl;
else
{
func = TREE_TYPE (TREE_OPERAND (exp, 0));
if (POINTER_TYPE_P (func))
func = TREE_TYPE (func);
}
/* Check that the return value locations are the same. Like
if we are returning floats on the 80387 register stack, we cannot
make a sibcall from a function that doesn't return a float to a
function that does or, conversely, from a function that does return
a float to a function that doesn't; the necessary stack adjustment
would not be executed. This is also the place we notice
differences in the return value ABI. Note that it is ok for one
of the functions to have void return type as long as the return
value of the other is passed in a register. */
a = m68k_function_value (TREE_TYPE (exp), func);
b = m68k_function_value (TREE_TYPE (DECL_RESULT (current_function_decl)),
current_function_decl);
if (VOID_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl))))
;
else if (!rtx_equal_p (a, b))
return false;
/* --- */
kind = m68k_get_function_kind (current_function_decl);
if (kind == m68k_fk_normal_function)
/* We can always sibcall from a normal function, because it's
undefined if it is calling an interrupt function. */
return true;
/* Otherwise we can only sibcall if the function kind is known to be
the same. */
if (decl && m68k_get_function_kind (decl) == kind)
return true;
return false;
}
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41302
