/* Language independent return value optimizations
- Copyright (C) 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2007, 2008, 2009 Free Software Foundation, Inc.
This file is part of GCC.
static tree
finalize_nrv_r (tree *tp, int *walk_subtrees, void *data)
{
- struct nrv_data *dp = (struct nrv_data *)data;
+ struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
+ struct nrv_data *dp = (struct nrv_data *) wi->info;
/* No need to walk into types. */
if (TYPE_P (*tp))
tree result_type = TREE_TYPE (result);
tree found = NULL;
basic_block bb;
- block_stmt_iterator bsi;
+ gimple_stmt_iterator gsi;
struct nrv_data data;
/* If this function does not return an aggregate type in memory, then
if (is_gimple_reg_type (result_type))
return 0;
+ /* If the front end already did something like this, don't do it here. */
+ if (DECL_NAME (result))
+ return 0;
+
/* Look through each block for assignments to the RESULT_DECL. */
FOR_EACH_BB (bb)
{
- for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
- tree stmt = bsi_stmt (bsi);
- tree ret_expr;
+ gimple stmt = gsi_stmt (gsi);
+ tree ret_val;
- if (TREE_CODE (stmt) == RETURN_EXPR)
+ if (gimple_code (stmt) == GIMPLE_RETURN)
{
/* In a function with an aggregate return value, the
gimplifier has changed all non-empty RETURN_EXPRs to
return the RESULT_DECL. */
- ret_expr = TREE_OPERAND (stmt, 0);
- if (ret_expr)
- gcc_assert (ret_expr == result);
+ ret_val = gimple_return_retval (stmt);
+ if (ret_val)
+ gcc_assert (ret_val == result);
}
- else if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
- && GIMPLE_STMT_OPERAND (stmt, 0) == result)
+ else if (gimple_has_lhs (stmt)
+ && gimple_get_lhs (stmt) == result)
{
- ret_expr = GIMPLE_STMT_OPERAND (stmt, 1);
+ tree rhs;
+
+ if (!gimple_assign_copy_p (stmt))
+ return 0;
+
+ rhs = gimple_assign_rhs1 (stmt);
/* Now verify that this return statement uses the same value
as any previously encountered return statement. */
/* If we found a return statement using a different variable
than previous return statements, then we can not perform
NRV optimizations. */
- if (found != ret_expr)
+ if (found != rhs)
return 0;
}
else
- found = ret_expr;
+ found = rhs;
/* The returned value must be a local automatic variable of the
same type and alignment as the function's result. */
TREE_TYPE (found)))
return 0;
}
- else if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
+ else if (gimple_has_lhs (stmt))
{
- tree addr = get_base_address (GIMPLE_STMT_OPERAND (stmt, 0));
+ tree addr = get_base_address (gimple_get_lhs (stmt));
/* If there's any MODIFY of component of RESULT,
then bail out. */
if (addr && addr == result)
/* At this point we know that all the return statements return the
same local which has suitable attributes for NRV. Copy debugging
- information from FOUND to RESULT. */
- DECL_NAME (result) = DECL_NAME (found);
- DECL_SOURCE_LOCATION (result) = DECL_SOURCE_LOCATION (found);
- DECL_ABSTRACT_ORIGIN (result) = DECL_ABSTRACT_ORIGIN (found);
+ information from FOUND to RESULT if it will be useful. But don't set
+ DECL_ABSTRACT_ORIGIN to point at another function. */
+ if (!DECL_IGNORED_P (found)
+ && !(DECL_ABSTRACT_ORIGIN (found)
+ && DECL_CONTEXT (DECL_ABSTRACT_ORIGIN (found)) != current_function_decl))
+ {
+ DECL_NAME (result) = DECL_NAME (found);
+ DECL_SOURCE_LOCATION (result) = DECL_SOURCE_LOCATION (found);
+ DECL_ABSTRACT_ORIGIN (result) = DECL_ABSTRACT_ORIGIN (found);
+ }
+
TREE_ADDRESSABLE (result) = TREE_ADDRESSABLE (found);
/* Now walk through the function changing all references to VAR to be
data.result = result;
FOR_EACH_BB (bb)
{
- for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
+ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
{
- tree *tp = bsi_stmt_ptr (bsi);
+ gimple stmt = gsi_stmt (gsi);
/* If this is a copy from VAR to RESULT, remove it. */
- if (TREE_CODE (*tp) == GIMPLE_MODIFY_STMT
- && GIMPLE_STMT_OPERAND (*tp, 0) == result
- && GIMPLE_STMT_OPERAND (*tp, 1) == found)
- bsi_remove (&bsi, true);
+ if (gimple_assign_copy_p (stmt)
+ && gimple_assign_lhs (stmt) == result
+ && gimple_assign_rhs1 (stmt) == found)
+ gsi_remove (&gsi, true);
else
{
- walk_tree (tp, finalize_nrv_r, &data, 0);
- bsi_next (&bsi);
+ struct walk_stmt_info wi;
+ memset (&wi, 0, sizeof (wi));
+ wi.info = &data;
+ walk_gimple_op (stmt, finalize_nrv_r, &wi);
+ gsi_next (&gsi);
}
}
}
return 0;
}
+static bool
+gate_pass_return_slot (void)
+{
+ return optimize > 0;
+}
+
struct gimple_opt_pass pass_nrv =
{
{
GIMPLE_PASS,
"nrv", /* name */
- NULL, /* gate */
+ gate_pass_return_slot, /* gate */
tree_nrv, /* execute */
NULL, /* sub */
NULL, /* next */
return true;
}
-/* Walk through the function looking for GIMPLE_MODIFY_STMTs with calls that
+/* Walk through the function looking for GIMPLE_ASSIGNs with calls that
return in memory on the RHS. For each of these, determine whether it is
safe to pass the address of the LHS as the return slot, and mark the
call appropriately if so.
FOR_EACH_BB (bb)
{
- block_stmt_iterator i;
- for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
+ gimple_stmt_iterator gsi;
+ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
- tree stmt = bsi_stmt (i);
- tree call;
-
- if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
- && (call = GIMPLE_STMT_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 (GIMPLE_STMT_OPERAND (stmt, 0)) ? 1 : 0;
+ gimple stmt = gsi_stmt (gsi);
+ bool slot_opt_p;
+
+ if (is_gimple_call (stmt)
+ && gimple_call_lhs (stmt)
+ && !gimple_call_return_slot_opt_p (stmt)
+ && aggregate_value_p (TREE_TYPE (gimple_call_lhs (stmt)),
+ gimple_call_fndecl (stmt))
+ )
+ {
+ /* Check if the location being assigned to is
+ call-clobbered. */
+ slot_opt_p = dest_safe_for_nrv_p (gimple_call_lhs (stmt));
+ gimple_call_set_return_slot_opt (stmt, slot_opt_p);
+ }
}
}
return 0;
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
- 0, /* tv_id */
+ TV_NONE, /* tv_id */
PROP_ssa | PROP_alias, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
OSDN Git Service
