static unsigned int
execute_return_slot_opt (void)
{
basic_block bb;
FOR_EACH_BB (bb)
{
block_stmt_iterator i;
for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
{
tree stmt = bsi_stmt (i);
tree call;
if (TREE_CODE (stmt) == MODIFY_EXPR
&& (call = TREE_OPERAND (stmt, 1),
TREE_CODE (call) == CALL_EXPR)
&& !CALL_EXPR_RETURN_SLOT_OPT (call)
&& aggregate_value_p (call, call))
/* Check if the location being assigned to is
call-clobbered. */
CALL_EXPR_RETURN_SLOT_OPT (call) =
dest_safe_for_nrv_p (TREE_OPERAND (stmt, 0)) ? 1 : 0;
}
}
return 0;
}
static void
execute_return_slot_opt (void)
{
basic_block bb;
FOR_EACH_BB (bb)
{
block_stmt_iterator i;
for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
{
tree stmt = bsi_stmt (i);
tree call;
if (TREE_CODE (stmt) == MODIFY_EXPR
&& (call = TREE_OPERAND (stmt, 1),
TREE_CODE (call) == CALL_EXPR)
&& !CALL_EXPR_RETURN_SLOT_OPT (call)
&& aggregate_value_p (call, call))
{
def_operand_p def_p;
ssa_op_iter op_iter;
/* We determine whether or not the LHS address escapes by
asking whether it is call clobbered. When the LHS isn't a
simple decl, we need to check the VDEFs, so it's simplest
to just loop through all the DEFs. */
FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, op_iter, SSA_OP_ALL_DEFS)
{
tree def = DEF_FROM_PTR (def_p);
if (TREE_CODE (def) == SSA_NAME)
def = SSA_NAME_VAR (def);
if (is_call_clobbered (def))
goto unsafe;
}
/* No defs are call clobbered, so the optimization is safe. */
CALL_EXPR_RETURN_SLOT_OPT (call) = 1;
/* This is too late to mark the target addressable like we do
in gimplify_modify_expr_rhs, but that's OK; anything that
wasn't already addressable was handled there. */
unsafe:;
}
}
int
cp_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
{
int saved_stmts_are_full_exprs_p = 0;
enum tree_code code = TREE_CODE (*expr_p);
enum gimplify_status ret;
if (STATEMENT_CODE_P (code))
{
saved_stmts_are_full_exprs_p = stmts_are_full_exprs_p ();
current_stmt_tree ()->stmts_are_full_exprs_p
= STMT_IS_FULL_EXPR_P (*expr_p);
}
switch (code)
{
case PTRMEM_CST:
*expr_p = cplus_expand_constant (*expr_p);
ret = GS_OK;
break;
case AGGR_INIT_EXPR:
simplify_aggr_init_expr (expr_p);
ret = GS_OK;
break;
case VEC_INIT_EXPR:
{
location_t loc = input_location;
tree init = VEC_INIT_EXPR_INIT (*expr_p);
int from_array = (init && TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE);
gcc_assert (EXPR_HAS_LOCATION (*expr_p));
input_location = EXPR_LOCATION (*expr_p);
*expr_p = build_vec_init (VEC_INIT_EXPR_SLOT (*expr_p), NULL_TREE,
init, VEC_INIT_EXPR_VALUE_INIT (*expr_p),
from_array,
tf_warning_or_error);
cp_genericize_tree (expr_p);
ret = GS_OK;
input_location = loc;
}
break;
case THROW_EXPR:
/* FIXME communicate throw type to back end, probably by moving
THROW_EXPR into ../tree.def. */
*expr_p = TREE_OPERAND (*expr_p, 0);
ret = GS_OK;
break;
case MUST_NOT_THROW_EXPR:
ret = gimplify_must_not_throw_expr (expr_p, pre_p);
break;
/* We used to do this for MODIFY_EXPR as well, but that's unsafe; the
LHS of an assignment might also be involved in the RHS, as in bug
25979. */
case INIT_EXPR:
if (fn_contains_cilk_spawn_p (cfun)
&& cilk_detect_spawn_and_unwrap (expr_p)
&& !seen_error ())
return (enum gimplify_status) gimplify_cilk_spawn (expr_p);
cp_gimplify_init_expr (expr_p);
if (TREE_CODE (*expr_p) != INIT_EXPR)
return GS_OK;
/* Otherwise fall through. */
case MODIFY_EXPR:
{
if (fn_contains_cilk_spawn_p (cfun)
&& cilk_detect_spawn_and_unwrap (expr_p)
&& !seen_error ())
return (enum gimplify_status) gimplify_cilk_spawn (expr_p);
/* If the back end isn't clever enough to know that the lhs and rhs
types are the same, add an explicit conversion. */
tree op0 = TREE_OPERAND (*expr_p, 0);
tree op1 = TREE_OPERAND (*expr_p, 1);
if (!error_operand_p (op0)
&& !error_operand_p (op1)
&& (TYPE_STRUCTURAL_EQUALITY_P (TREE_TYPE (op0))
|| TYPE_STRUCTURAL_EQUALITY_P (TREE_TYPE (op1)))
&& !useless_type_conversion_p (TREE_TYPE (op1), TREE_TYPE (op0)))
TREE_OPERAND (*expr_p, 1) = build1 (VIEW_CONVERT_EXPR,
TREE_TYPE (op0), op1);
else if ((is_gimple_lvalue (op1) || INDIRECT_REF_P (op1)
|| (TREE_CODE (op1) == CONSTRUCTOR
&& CONSTRUCTOR_NELTS (op1) == 0
&& !TREE_CLOBBER_P (op1))
|| (TREE_CODE (op1) == CALL_EXPR
&& !CALL_EXPR_RETURN_SLOT_OPT (op1)))
&& is_really_empty_class (TREE_TYPE (op0)))
{
/* Remove any copies of empty classes. We check that the RHS
has a simple form so that TARGET_EXPRs and non-empty
CONSTRUCTORs get reduced properly, and we leave the return
slot optimization alone because it isn't a copy (FIXME so it
shouldn't be represented as one).
Also drop volatile variables on the RHS to avoid infinite
recursion from gimplify_expr trying to load the value. */
if (!TREE_SIDE_EFFECTS (op1)
|| (DECL_P (op1) && TREE_THIS_VOLATILE (op1)))
*expr_p = op0;
else if (TREE_CODE (op1) == MEM_REF
&& TREE_THIS_VOLATILE (op1))
{
/* Similarly for volatile MEM_REFs on the RHS. */
if (!TREE_SIDE_EFFECTS (TREE_OPERAND (op1, 0)))
*expr_p = op0;
else
*expr_p = build2 (COMPOUND_EXPR, TREE_TYPE (*expr_p),
TREE_OPERAND (op1, 0), op0);
}
else
*expr_p = build2 (COMPOUND_EXPR, TREE_TYPE (*expr_p),
op0, op1);
}
}
ret = GS_OK;
break;
case EMPTY_CLASS_EXPR:
/* We create an empty CONSTRUCTOR with RECORD_TYPE. */
*expr_p = build_constructor (TREE_TYPE (*expr_p), NULL);
ret = GS_OK;
break;
case BASELINK:
*expr_p = BASELINK_FUNCTIONS (*expr_p);
ret = GS_OK;
break;
case TRY_BLOCK:
genericize_try_block (expr_p);
ret = GS_OK;
break;
case HANDLER:
genericize_catch_block (expr_p);
ret = GS_OK;
break;
case EH_SPEC_BLOCK:
genericize_eh_spec_block (expr_p);
ret = GS_OK;
break;
case USING_STMT:
gcc_unreachable ();
case FOR_STMT:
case WHILE_STMT:
case DO_STMT:
case SWITCH_STMT:
case CONTINUE_STMT:
case BREAK_STMT:
gcc_unreachable ();
case OMP_FOR:
case OMP_SIMD:
case OMP_DISTRIBUTE:
ret = cp_gimplify_omp_for (expr_p, pre_p);
break;
case EXPR_STMT:
gimplify_expr_stmt (expr_p);
ret = GS_OK;
break;
case UNARY_PLUS_EXPR:
{
tree arg = TREE_OPERAND (*expr_p, 0);
tree type = TREE_TYPE (*expr_p);
*expr_p = (TREE_TYPE (arg) != type) ? fold_convert (type, arg)
: arg;
ret = GS_OK;
}
break;
case CILK_SPAWN_STMT:
gcc_assert
(fn_contains_cilk_spawn_p (cfun)
&& cilk_detect_spawn_and_unwrap (expr_p));
/* If errors are seen, then just process it as a CALL_EXPR. */
if (!seen_error ())
return (enum gimplify_status) gimplify_cilk_spawn (expr_p);
case CALL_EXPR:
if (fn_contains_cilk_spawn_p (cfun)
&& cilk_detect_spawn_and_unwrap (expr_p)
&& !seen_error ())
return (enum gimplify_status) gimplify_cilk_spawn (expr_p);
default:
ret = (enum gimplify_status) c_gimplify_expr (expr_p, pre_p, post_p);
break;
}
/* Restore saved state. */
if (STATEMENT_CODE_P (code))
current_stmt_tree ()->stmts_are_full_exprs_p
= saved_stmts_are_full_exprs_p;
return ret;
}
