gcc/
* regrename.c (struct du_head): Add new element length.
(sort_du_head, get_tail_du_head, merge, merge_sort_callback):
New functions of merge sort implementation to du_head list.
(regrename_optimize): Sort du_head linked list by length.
(create_new_chain): Initialize length.
(scan_rtx_reg): Increase du_chain_length for non-debug insns.
(gate_handle_regrename): Turn on this pass when Os is set.
@@ -51,6 +51,8 @@ struct du_head
struct du_head *next_chain;
/* The first and last elements of this chain. */
struct du_chain *first, *last;
+ /* The length of du_chain for non-debug insns. */
+ int length;
/* Describes the register being tracked. */
unsigned regno, nregs;
@@ -154,6 +156,149 @@ merge_overlapping_regs (HARD_REG_SET *pset, struct du_head *head)
}
}
+/* Get the next LENGTH element in list from START. If length of
+ list from START is less than LENGTH, return the last one. */
+static struct du_head *
+get_tail_du_head (struct du_head *start, int length)
+{
+ while (length-- && start->next_chain != NULL)
+ {
+ start = start->next_chain;
+ }
+
+ return start;
+}
+
+
+/* Merge the linked list starting from START_NODE. CMP is callback
+ for comparison. */
+static struct du_head *
+merge(struct du_head **start_node, int current_length,
+ int(*cmp)(const struct du_head *, const struct du_head *))
+{
+ int can_merge_p, i, left_count, right_count;
+ struct du_head *left, *right;
+ /* Current node of sort result. */
+ struct du_head *current_sorted_node;
+ /* Tail node of sort, used to connect with next piece of list. */
+ struct du_head *current_tail_node;
+
+ if (*start_node == NULL)
+ return NULL;
+
+ can_merge_p = 1;
+ left = right = *start_node;
+ right_count = left_count = 0;
+
+ for (i = 0; i < current_length; i++)
+ {
+ right = right->next_chain;
+ if (right == NULL)
+ {
+ can_merge_p = 0;
+ break;
+ }
+ }
+
+ if (!can_merge_p)
+ return NULL;
+
+ /* Initialize current_sorted_node. */
+ if (cmp (left, right))
+ {
+ ++right_count;
+ current_sorted_node = right;
+ *start_node = right;
+ right = right->next_chain;
+ }
+ else
+ {
+ ++left_count;
+ current_sorted_node = left;
+ left = left->next_chain;
+ }
+
+ while (1)
+ {
+ if (left_count == current_length || left == NULL)
+ {
+ current_sorted_node->next_chain = right;
+ current_tail_node =
+ get_tail_du_head (current_sorted_node,
+ current_length - right_count);
+
+ break;
+ }
+ else if (right_count == current_length || right == NULL)
+ {
+ /* Save the head node of next piece of linked list. */
+ struct du_head *tmp = current_sorted_node->next_chain;
+
+ current_sorted_node->next_chain = left;
+ current_tail_node =
+ get_tail_du_head (current_sorted_node,
+ current_length - left_count);
+ /* Connect sorted list to next piece of list. */
+ current_tail_node->next_chain = tmp;
+ break;
+ }
+ else
+ {
+ /* Normal merge operations. */
+ if (cmp (left, right))
+ {
+ right_count++;
+ current_sorted_node->next_chain = right;
+ right = right->next_chain;
+ }
+ else
+ {
+ left_count++;
+ current_sorted_node->next_chain = left;
+ left = left->next_chain;
+ }
+ current_sorted_node = current_sorted_node->next_chain;
+ }
+ }
+ return current_tail_node->next_chain != NULL ?
+ current_tail_node : NULL;
+}
+
+
+/* Non-recursive merge sort to du_head list. */
+static void
+sort_du_head (struct du_head **head,
+ int(*cmp)(const struct du_head *, const struct du_head *))
+{
+ int current_length = 1;
+ struct du_head *last_tail;
+ while (1)
+ {
+ last_tail = merge(head, current_length, cmp);
+ if (last_tail != NULL)
+ {
+ do
+ {
+ last_tail = merge (&last_tail->next_chain,
+ current_length, cmp);
+ }
+ while (last_tail != NULL);
+ current_length *= 2;
+ }
+ else
+ break;
+ }
+}
+
+/* Call back function of merge sort. Return true if A is less than
+ B, otherwise return false. */
+static int
+merge_sort_callback(const struct du_head *a,
+ const struct du_head *b)
+{
+ return a->length < b->length;
+}
+
/* Perform register renaming on the current function. */
static unsigned int
@@ -195,6 +340,8 @@ regrename_optimize (void)
if (dump_file)
dump_def_use_chain (all_chains);
+ sort_du_head (&all_chains, merge_sort_callback);
+
CLEAR_HARD_REG_SET (unavailable);
/* Don't clobber traceback for noreturn functions. */
if (frame_pointer_needed)
@@ -251,8 +398,11 @@ regrename_optimize (void)
if (DEBUG_INSN_P (tmp->insn))
continue;
n_uses++;
+#ifndef PREFERRED_RENAME_CLASS
+#define PREFERRED_RENAME_CLASS(CLASS) CLASS
+#endif
IOR_COMPL_HARD_REG_SET (this_unavailable,
- reg_class_contents[tmp->cl]);
+ reg_class_contents[PREFERRED_RENAME_CLASS(tmp->cl)]);
}
if (n_uses < 2)
@@ -265,13 +415,13 @@ regrename_optimize (void)
/* Now potential_regs is a reasonable approximation, let's
have a closer look at each register still in there. */
- for (new_reg = 0; new_reg < FIRST_PSEUDO_REGISTER; new_reg++)
+ for (new_reg = FIRST_PSEUDO_REGISTER - 1; new_reg >= 0; new_reg--)
{
enum machine_mode mode = GET_MODE (*this_head->first->loc);
int nregs = hard_regno_nregs[new_reg][mode];
for (i = nregs - 1; i >= 0; --i)
- if (TEST_HARD_REG_BIT (this_unavailable, new_reg + i)
+ if (TEST_HARD_REG_BIT (this_unavailable, new_reg + i)
|| fixed_regs[new_reg + i]
|| global_regs[new_reg + i]
/* Can't use regs which aren't saved by the prologue. */
@@ -527,6 +677,7 @@ create_new_chain (unsigned this_regno, unsigned this_nregs, rtx *loc,
head->need_caller_save_reg = 0;
head->cannot_rename = 0;
head->terminated = 0;
+ head->length = 0;
VEC_safe_push (du_head_p, heap, id_to_chain, head);
head->id = current_id++;
@@ -572,6 +723,8 @@ create_new_chain (unsigned this_regno, unsigned this_nregs, rtx *loc,
this_du->loc = loc;
this_du->insn = insn;
this_du->cl = cl;
+
+ head->length = 1;
}
static void
@@ -661,6 +814,8 @@ scan_rtx_reg (rtx insn, rtx *loc, enum reg_class cl, enum scan_actions action,
head->last->next_use = this_du;
head->last = this_du;
+ if (!DEBUG_INSN_P (insn))
+ head->length++;
}
/* Avoid adding the same location in a DEBUG_INSN multiple times,
which could happen with non-exact overlap. */
@@ -1354,11 +1509,12 @@ dump_def_use_chain (struct du_head *head)
}
}
+
static bool
gate_handle_regrename (void)
{
- return (optimize > 0 && (flag_rename_registers));
+ return ((optimize > 0 || optimize_size) && (flag_rename_registers));
}
struct rtl_opt_pass pass_regrename =