I noticed that gimplification made some code in tree-eh.c unnecessary,
but did not actually remove it. This patch cleans up tree-eh.c to
remove the unnecessary code and simplify the do_return_redirection
function slightly. Bootstrapped and ran testsuite on
x86_64-unknown-linux-gnu. Committed to mainline.
Ian
2011-10-25 Ian Lance Taylor <i...@google.com>
* tree-eh.c (do_return_redirection): Remove return_value_p
parameter. Change all callers.
(lower_try_finally_nofallthru): Remove local return_val.
(lower_try_finally_onedest): Likewise.
(lower_try_finally_copy): Likewise.
(lower_try_finally_switch): Likewise.
Index: tree-eh.c
===================================================================
--- tree-eh.c (revision 180435)
+++ tree-eh.c (working copy)
@@ -711,66 +711,35 @@ verify_norecord_switch_expr (struct leh_
#define verify_norecord_switch_expr(state, switch_expr)
#endif
-/* Redirect a RETURN_EXPR pointed to by STMT_P to FINLAB. Place in CONT_P
- whatever is needed to finish the return. If MOD is non-null, insert it
- before the new branch. RETURN_VALUE_P is a cache containing a temporary
- variable to be used in manipulating the value returned from the function. */
+/* Redirect a RETURN_EXPR pointed to by Q to FINLAB. If MOD is
+ non-null, insert it before the new branch. */
static void
-do_return_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod,
- tree *return_value_p)
+do_return_redirection (struct goto_queue_node *q, tree finlab, gimple_seq mod)
{
- tree ret_expr;
gimple x;
- /* In the case of a return, the queue node must be a gimple statement. */
+ /* In the case of a return, the queue node must be a gimple statement. */
gcc_assert (!q->is_label);
- ret_expr = gimple_return_retval (q->stmt.g);
+ /* Note that the return value may have already been computed, e.g.,
- if (ret_expr)
- {
- if (!*return_value_p)
- *return_value_p = ret_expr;
- else
- gcc_assert (*return_value_p == ret_expr);
- q->cont_stmt = q->stmt.g;
- /* The nasty part about redirecting the return value is that the
- return value itself is to be computed before the FINALLY block
- is executed. e.g.
-
- int x;
- int foo (void)
- {
- x = 0;
- try {
- return x;
- } finally {
- x++;
- }
- }
-
- should return 0, not 1. Arrange for this to happen by copying
- computed the return value into a local temporary. This also
- allows us to redirect multiple return statements through the
- same destination block; whether this is a net win or not really
- depends, I guess, but it does make generation of the switch in
- lower_try_finally_switch easier. */
-
- if (TREE_CODE (ret_expr) == RESULT_DECL)
+ int x;
+ int foo (void)
{
- if (!*return_value_p)
- *return_value_p = ret_expr;
- else
- gcc_assert (*return_value_p == ret_expr);
- q->cont_stmt = q->stmt.g;
+ x = 0;
+ try {
+ return x;
+ } finally {
+ x++;
+ }
}
- else
- gcc_unreachable ();
- }
- else
- /* If we don't return a value, all return statements are the same. */
- q->cont_stmt = q->stmt.g;
+
+ should return 0, not 1. We don't have to do anything to make
+ this happens because the return value has been placed in the
+ RESULT_DECL already. */
+
+ q->cont_stmt = q->stmt.g;
if (!q->repl_stmt)
q->repl_stmt = gimple_seq_alloc ();
@@ -1041,7 +1010,7 @@ static void
lower_try_finally_nofallthru (struct leh_state *state,
struct leh_tf_state *tf)
{
- tree lab, return_val;
+ tree lab;
gimple x;
gimple_seq finally;
struct goto_queue_node *q, *qe;
@@ -1055,12 +1024,11 @@ lower_try_finally_nofallthru (struct leh
x = gimple_build_label (lab);
gimple_seq_add_stmt (&tf->top_p_seq, x);
- return_val = NULL;
q = tf->goto_queue;
qe = q + tf->goto_queue_active;
for (; q < qe; ++q)
if (q->index < 0)
- do_return_redirection (q, lab, NULL, &return_val);
+ do_return_redirection (q, lab, NULL);
else
do_goto_redirection (q, lab, NULL, tf);
@@ -1126,9 +1094,8 @@ lower_try_finally_onedest (struct leh_st
if (tf->may_return)
{
/* Reachable by return expressions only. Redirect them. */
- tree return_val = NULL;
for (; q < qe; ++q)
- do_return_redirection (q, finally_label, NULL, &return_val);
+ do_return_redirection (q, finally_label, NULL);
replace_goto_queue (tf);
}
else
@@ -1197,7 +1164,6 @@ lower_try_finally_copy (struct leh_state
if (tf->goto_queue)
{
struct goto_queue_node *q, *qe;
- tree return_val = NULL;
int return_index, index;
struct labels_s
{
@@ -1230,7 +1196,7 @@ lower_try_finally_copy (struct leh_state
= create_artificial_label (tf_loc);
if (index == return_index)
- do_return_redirection (q, lab, NULL, &return_val);
+ do_return_redirection (q, lab, NULL);
else
do_goto_redirection (q, lab, NULL, tf);
@@ -1257,7 +1223,7 @@ lower_try_finally_copy (struct leh_state
lab = labels[index].label;
if (index == return_index)
- do_return_redirection (q, lab, NULL, &return_val);
+ do_return_redirection (q, lab, NULL);
else
do_goto_redirection (q, lab, NULL, tf);
}
@@ -1280,7 +1246,6 @@ static void
lower_try_finally_switch (struct leh_state *state, struct leh_tf_state *tf)
{
struct goto_queue_node *q, *qe;
- tree return_val = NULL;
tree finally_tmp, finally_label;
int return_index, eh_index, fallthru_index;
int nlabels, ndests, j, last_case_index;
@@ -1401,7 +1366,7 @@ lower_try_finally_switch (struct leh_sta
build_int_cst (integer_type_node,
return_index));
gimple_seq_add_stmt (&mod, x);
- do_return_redirection (q, finally_label, mod, &return_val);
+ do_return_redirection (q, finally_label, mod);
switch_id = return_index;
}
else
