#include "cfgloop.h"
#include "ira.h"
#include "emit-rtl.h" /* FIXME: Can go away once crtl is moved to rtl.h. */
+#include "hashtab.h"
#ifdef INSN_SCHEDULING
int issue_rate;
+/* This can be set to true by a backend if the scheduler should not
+ enable a DCE pass. */
+bool sched_no_dce;
+
/* sched-verbose controls the amount of debugging output the
scheduler prints. It is controlled by -fsched-verbose=N:
N>0 and no -DSR : the output is directed to stderr.
struct common_sched_info_def *common_sched_info;
#define INSN_TICK(INSN) (HID (INSN)->tick)
+#define INSN_EXACT_TICK(INSN) (HID (INSN)->exact_tick)
+#define INSN_TICK_ESTIMATE(INSN) (HID (INSN)->tick_estimate)
#define INTER_TICK(INSN) (HID (INSN)->inter_tick)
+#define FEEDS_BACKTRACK_INSN(INSN) (HID (INSN)->feeds_backtrack_insn)
+#define SHADOW_P(INSN) (HID (INSN)->shadow_p)
/* If INSN_TICK of an instruction is equal to INVALID_TICK,
then it should be recalculated from scratch. */
/* Scheduling clock. */
static int clock_var;
+/* Clock at which the previous instruction was issued. */
+static int last_clock_var;
+
+/* Set to true if, when queuing a shadow insn, we discover that it would be
+ scheduled too late. */
+static bool must_backtrack;
+
+/* The following variable value is number of essential insns issued on
+ the current cycle. An insn is essential one if it changes the
+ processors state. */
+int cycle_issued_insns;
+
/* This records the actual schedule. It is built up during the main phase
of schedule_block, and afterwards used to reorder the insns in the RTL. */
static VEC(rtx, heap) *scheduled_insns;
return haifa_classify_rtx (PATTERN (insn));
}
+/* A structure to record a pair of insns where the first one is a real
+ insn that has delay slots, and the second is its delayed shadow.
+ I1 is scheduled normally and will emit an assembly instruction,
+ while I2 describes the side effect that takes place at the
+ transition between cycles CYCLES and (CYCLES + 1) after I1. */
+struct delay_pair
+{
+ struct delay_pair *next_same_i1;
+ rtx i1, i2;
+ int cycles;
+};
+
+/* Two hash tables to record delay_pairs, one indexed by I1 and the other
+ indexed by I2. */
+static htab_t delay_htab;
+static htab_t delay_htab_i2;
+
+/* Returns a hash value for X (which really is a delay_pair), based on
+ hashing just I1. */
+static hashval_t
+delay_hash_i1 (const void *x)
+{
+ return htab_hash_pointer (((const struct delay_pair *) x)->i1);
+}
+
+/* Returns a hash value for X (which really is a delay_pair), based on
+ hashing just I2. */
+static hashval_t
+delay_hash_i2 (const void *x)
+{
+ return htab_hash_pointer (((const struct delay_pair *) x)->i2);
+}
+
+/* Return nonzero if I1 of pair X is the same as that of pair Y. */
+static int
+delay_i1_eq (const void *x, const void *y)
+{
+ return ((const struct delay_pair *) x)->i1 == y;
+}
+
+/* Return nonzero if I2 of pair X is the same as that of pair Y. */
+static int
+delay_i2_eq (const void *x, const void *y)
+{
+ return ((const struct delay_pair *) x)->i2 == y;
+}
+
+/* This function can be called by a port just before it starts the
+ final scheduling pass. It records the fact that an instruction
+ with delay slots has been split into two insns, I1 and I2. The
+ first one will be scheduled normally and initiates the operation.
+ The second one is a shadow which must follow a specific number of
+ CYCLES after I1; its only purpose is to show the side effect that
+ occurs at that cycle in the RTL. If a JUMP_INSN or a CALL_INSN has
+ been split, I1 should be a normal INSN, while I2 retains the
+ original insn type. */
+
+void
+record_delay_slot_pair (rtx i1, rtx i2, int cycles)
+{
+ struct delay_pair *p = XNEW (struct delay_pair);
+ struct delay_pair **slot;
+
+ p->i1 = i1;
+ p->i2 = i2;
+ p->cycles = cycles;
+
+ if (!delay_htab)
+ {
+ delay_htab = htab_create (10, delay_hash_i1, delay_i1_eq, NULL);
+ delay_htab_i2 = htab_create (10, delay_hash_i2, delay_i2_eq, free);
+ }
+ slot = ((struct delay_pair **)
+ htab_find_slot_with_hash (delay_htab, i1, htab_hash_pointer (i1),
+ INSERT));
+ p->next_same_i1 = *slot;
+ *slot = p;
+ slot = ((struct delay_pair **)
+ htab_find_slot_with_hash (delay_htab_i2, i2, htab_hash_pointer (i2),
+ INSERT));
+ *slot = p;
+}
+
+/* For a pair P of insns, return the fixed distance in cycles from the first
+ insn after which the second must be scheduled. */
+static int
+pair_delay (struct delay_pair *p)
+{
+ return p->cycles;
+}
+
+/* Given an insn INSN, add a dependence on its delayed shadow if it
+ has one. Also try to find situations where shadows depend on each other
+ and add dependencies to the real insns to limit the amount of backtracking
+ needed. */
+void
+add_delay_dependencies (rtx insn)
+{
+ struct delay_pair *pair;
+ sd_iterator_def sd_it;
+ dep_t dep;
+
+ if (!delay_htab)
+ return;
+
+ pair
+ = (struct delay_pair *)htab_find_with_hash (delay_htab_i2, insn,
+ htab_hash_pointer (insn));
+ if (!pair)
+ return;
+ add_dependence (insn, pair->i1, REG_DEP_ANTI);
+
+ FOR_EACH_DEP (pair->i2, SD_LIST_BACK, sd_it, dep)
+ {
+ rtx pro = DEP_PRO (dep);
+ struct delay_pair *other_pair
+ = (struct delay_pair *)htab_find_with_hash (delay_htab_i2, pro,
+ htab_hash_pointer (pro));
+ if (!other_pair)
+ continue;
+ if (pair_delay (other_pair) >= pair_delay (pair))
+ {
+ if (sched_verbose >= 4)
+ {
+ fprintf (sched_dump, ";;\tadding dependence %d <- %d\n",
+ INSN_UID (other_pair->i1),
+ INSN_UID (pair->i1));
+ fprintf (sched_dump, ";;\tpair1 %d <- %d, cost %d\n",
+ INSN_UID (pair->i1),
+ INSN_UID (pair->i2),
+ pair_delay (pair));
+ fprintf (sched_dump, ";;\tpair2 %d <- %d, cost %d\n",
+ INSN_UID (other_pair->i1),
+ INSN_UID (other_pair->i2),
+ pair_delay (other_pair));
+ }
+ add_dependence (pair->i1, other_pair->i1, REG_DEP_ANTI);
+ }
+ }
+}
+\f
/* Forward declarations. */
static int priority (rtx);
if (DEP_COST (link) != UNKNOWN_DEP_COST)
return DEP_COST (link);
+ if (delay_htab)
+ {
+ struct delay_pair *delay_entry;
+ delay_entry
+ = (struct delay_pair *)htab_find_with_hash (delay_htab_i2, used,
+ htab_hash_pointer (used));
+ if (delay_entry)
+ {
+ if (delay_entry->i1 == insn)
+ {
+ DEP_COST (link) = pair_delay (delay_entry);
+ return DEP_COST (link);
+ }
+ }
+ }
+
/* A USE insn should never require the value used to be computed.
This allows the computation of a function's result and parameter
values to overlap the return and call. We don't care about the
else
return INSN_TICK (tmp) - INSN_TICK (tmp2);
}
+
+ /* If we are doing backtracking in this schedule, prefer insns that
+ have forward dependencies with negative cost against an insn that
+ was already scheduled. */
+ if (current_sched_info->flags & DO_BACKTRACKING)
+ {
+ priority_val = FEEDS_BACKTRACK_INSN (tmp2) - FEEDS_BACKTRACK_INSN (tmp);
+ if (priority_val)
+ return priority_val;
+ }
+
/* Prefer insn with higher priority. */
priority_val = INSN_PRIORITY (tmp2) - INSN_PRIORITY (tmp);
{
int next_q = NEXT_Q_AFTER (q_ptr, n_cycles);
rtx link = alloc_INSN_LIST (insn, insn_queue[next_q]);
+ int new_tick;
gcc_assert (n_cycles <= max_insn_queue_index);
gcc_assert (!DEBUG_INSN_P (insn));
}
QUEUE_INDEX (insn) = next_q;
+
+ if (current_sched_info->flags & DO_BACKTRACKING)
+ {
+ new_tick = clock_var + n_cycles;
+ if (INSN_TICK (insn) == INVALID_TICK || INSN_TICK (insn) < new_tick)
+ INSN_TICK (insn) = new_tick;
+
+ if (INSN_EXACT_TICK (insn) != INVALID_TICK
+ && INSN_EXACT_TICK (insn) < clock_var + n_cycles)
+ {
+ must_backtrack = true;
+ if (sched_verbose >= 2)
+ fprintf (sched_dump, ";;\t\tcausing a backtrack.\n");
+ }
+ }
}
/* Remove INSN from queue. */
gcc_assert (QUEUE_INDEX (insn) != QUEUE_READY);
QUEUE_INDEX (insn) = QUEUE_READY;
+
+ if (INSN_EXACT_TICK (insn) != INVALID_TICK
+ && INSN_EXACT_TICK (insn) < clock_var)
+ {
+ must_backtrack = true;
+ }
}
/* Remove the element with the highest priority from the ready list and
fprintf (sched_dump, ";;\tAdvanced a state.\n");
}
-/* Clock at which the previous instruction was issued. */
-static int last_clock_var;
-
/* Update register pressure after scheduling INSN. */
static void
update_register_pressure (rtx insn)
{
/* True if no real insns have been scheduled in the current cycle. */
bool first_cycle_insn_p;
+ /* True if a shadow insn has been scheduled in the current cycle, which
+ means that no more normal insns can be issued. */
+ bool shadows_only_p;
/* Initialized with the machine's issue rate every cycle, and updated
by calls to the variable_issue hook. */
int can_issue_more;
}
}
+/* A structure to record enough data to allow us to backtrack the scheduler to
+ a previous state. */
+struct haifa_saved_data
+{
+ /* Next entry on the list. */
+ struct haifa_saved_data *next;
+
+ /* Backtracking is associated with scheduling insns that have delay slots.
+ DELAY_PAIR points to the structure that contains the insns involved, and
+ the number of cycles between them. */
+ struct delay_pair *delay_pair;
+
+ /* Data used by the frontend (e.g. sched-ebb or sched-rgn). */
+ void *fe_saved_data;
+ /* Data used by the backend. */
+ void *be_saved_data;
+
+ /* Copies of global state. */
+ int clock_var, last_clock_var;
+ struct ready_list ready;
+ state_t curr_state;
+
+ rtx last_scheduled_insn;
+ rtx last_nondebug_scheduled_insn;
+ int cycle_issued_insns;
+
+ /* Copies of state used in the inner loop of schedule_block. */
+ struct sched_block_state sched_block;
+
+ /* We don't need to save q_ptr, as its value is arbitrary and we can set it
+ to 0 when restoring. */
+ int q_size;
+ rtx *insn_queue;
+};
+
+/* A record, in reverse order, of all scheduled insns which have delay slots
+ and may require backtracking. */
+static struct haifa_saved_data *backtrack_queue;
+
+/* For every dependency of INSN, set the FEEDS_BACKTRACK_INSN bit according
+ to SET_P. */
+static void
+mark_backtrack_feeds (rtx insn, int set_p)
+{
+ sd_iterator_def sd_it;
+ dep_t dep;
+ FOR_EACH_DEP (insn, SD_LIST_HARD_BACK, sd_it, dep)
+ {
+ FEEDS_BACKTRACK_INSN (DEP_PRO (dep)) = set_p;
+ }
+}
+
+/* Make a copy of the INSN_LIST list LINK and return it. */
+static rtx
+copy_insn_list (rtx link)
+{
+ rtx new_queue;
+ rtx *pqueue = &new_queue;
+
+ for (; link; link = XEXP (link, 1))
+ {
+ rtx x = XEXP (link, 0);
+ rtx newlink = alloc_INSN_LIST (x, NULL);
+ *pqueue = newlink;
+ pqueue = &XEXP (newlink, 1);
+ }
+ *pqueue = NULL_RTX;
+ return new_queue;
+}
+
+/* Save the current scheduler state so that we can backtrack to it
+ later if necessary. PAIR gives the insns that make it necessary to
+ save this point. SCHED_BLOCK is the local state of schedule_block
+ that need to be saved. */
+static void
+save_backtrack_point (struct delay_pair *pair,
+ struct sched_block_state sched_block)
+{
+ int i;
+ struct haifa_saved_data *save = XNEW (struct haifa_saved_data);
+
+ save->curr_state = xmalloc (dfa_state_size);
+ memcpy (save->curr_state, curr_state, dfa_state_size);
+
+ save->ready.first = ready.first;
+ save->ready.n_ready = ready.n_ready;
+ save->ready.n_debug = ready.n_debug;
+ save->ready.veclen = ready.veclen;
+ save->ready.vec = XNEWVEC (rtx, ready.veclen);
+ memcpy (save->ready.vec, ready.vec, ready.veclen * sizeof (rtx));
+
+ save->insn_queue = XNEWVEC (rtx, max_insn_queue_index + 1);
+ save->q_size = q_size;
+ for (i = 0; i <= max_insn_queue_index; i++)
+ {
+ int q = NEXT_Q_AFTER (q_ptr, i);
+ save->insn_queue[i] = copy_insn_list (insn_queue[q]);
+ }
+
+ save->clock_var = clock_var;
+ save->last_clock_var = last_clock_var;
+ save->cycle_issued_insns = cycle_issued_insns;
+ save->last_scheduled_insn = last_scheduled_insn;
+ save->last_nondebug_scheduled_insn = last_nondebug_scheduled_insn;
+
+ save->sched_block = sched_block;
+
+ if (current_sched_info->save_state)
+ save->fe_saved_data = (*current_sched_info->save_state) ();
+
+ if (targetm.sched.alloc_sched_context)
+ {
+ save->be_saved_data = targetm.sched.alloc_sched_context ();
+ targetm.sched.init_sched_context (save->be_saved_data, false);
+ }
+ else
+ save->be_saved_data = NULL;
+
+ save->delay_pair = pair;
+
+ save->next = backtrack_queue;
+ backtrack_queue = save;
+
+ while (pair)
+ {
+ mark_backtrack_feeds (pair->i2, 1);
+ INSN_TICK (pair->i2) = INVALID_TICK;
+ INSN_EXACT_TICK (pair->i2) = clock_var + pair_delay (pair);
+ SHADOW_P (pair->i2) = true;
+ pair = pair->next_same_i1;
+ }
+}
+
+/* Pop entries from the SCHEDULED_INSNS vector up to and including INSN.
+ Restore their dependencies to an unresolved state, and mark them as
+ queued nowhere. */
+
+static void
+unschedule_insns_until (rtx insn)
+{
+ for (;;)
+ {
+ rtx last;
+ sd_iterator_def sd_it;
+ dep_t dep;
+
+ last = VEC_pop (rtx, scheduled_insns);
+
+ /* This will be changed by restore_backtrack_point if the insn is in
+ any queue. */
+ QUEUE_INDEX (last) = QUEUE_NOWHERE;
+ if (last != insn)
+ INSN_TICK (last) = INVALID_TICK;
+
+ for (sd_it = sd_iterator_start (last, SD_LIST_RES_FORW);
+ sd_iterator_cond (&sd_it, &dep);)
+ {
+ rtx con = DEP_CON (dep);
+ TODO_SPEC (con) |= HARD_DEP;
+ INSN_TICK (con) = INVALID_TICK;
+ sd_unresolve_dep (sd_it);
+ }
+
+ if (last == insn)
+ break;
+ }
+}
+
+/* Restore scheduler state from the topmost entry on the backtracking queue.
+ PSCHED_BLOCK_P points to the local data of schedule_block that we must
+ overwrite with the saved data.
+ The caller must already have called unschedule_insns_until. */
+
+static void
+restore_last_backtrack_point (struct sched_block_state *psched_block)
+
+{
+ rtx link;
+ int i;
+ struct haifa_saved_data *save = backtrack_queue;
+
+ backtrack_queue = save->next;
+
+ if (current_sched_info->restore_state)
+ (*current_sched_info->restore_state) (save->fe_saved_data);
+
+ if (targetm.sched.alloc_sched_context)
+ {
+ targetm.sched.set_sched_context (save->be_saved_data);
+ targetm.sched.free_sched_context (save->be_saved_data);
+ }
+
+ /* Clear the QUEUE_INDEX of everything in the ready list or one
+ of the queues. */
+ if (ready.n_ready > 0)
+ {
+ rtx *first = ready_lastpos (&ready);
+ for (i = 0; i < ready.n_ready; i++)
+ {
+ QUEUE_INDEX (first[i]) = QUEUE_NOWHERE;
+ INSN_TICK (first[i]) = INVALID_TICK;
+ }
+ }
+ for (i = 0; i <= max_insn_queue_index; i++)
+ {
+ int q = NEXT_Q_AFTER (q_ptr, i);
+
+ for (link = insn_queue[q]; link; link = XEXP (link, 1))
+ {
+ rtx x = XEXP (link, 0);
+ QUEUE_INDEX (x) = QUEUE_NOWHERE;
+ INSN_TICK (x) = INVALID_TICK;
+ }
+ free_INSN_LIST_list (&insn_queue[q]);
+ }
+
+ free (ready.vec);
+ ready = save->ready;
+
+ if (ready.n_ready > 0)
+ {
+ rtx *first = ready_lastpos (&ready);
+ for (i = 0; i < ready.n_ready; i++)
+ {
+ QUEUE_INDEX (first[i]) = QUEUE_READY;
+ INSN_TICK (first[i]) = save->clock_var;
+ }
+ }
+
+ q_ptr = 0;
+ q_size = save->q_size;
+ for (i = 0; i <= max_insn_queue_index; i++)
+ {
+ int q = NEXT_Q_AFTER (q_ptr, i);
+
+ insn_queue[q] = save->insn_queue[q];
+
+ for (link = insn_queue[q]; link; link = XEXP (link, 1))
+ {
+ rtx x = XEXP (link, 0);
+ QUEUE_INDEX (x) = i;
+ INSN_TICK (x) = save->clock_var + i;
+ }
+ }
+ free (save->insn_queue);
+
+ clock_var = save->clock_var;
+ last_clock_var = save->last_clock_var;
+ cycle_issued_insns = save->cycle_issued_insns;
+ last_scheduled_insn = save->last_scheduled_insn;
+ last_nondebug_scheduled_insn = save->last_nondebug_scheduled_insn;
+
+ *psched_block = save->sched_block;
+
+ memcpy (curr_state, save->curr_state, dfa_state_size);
+ free (save->curr_state);
+
+ mark_backtrack_feeds (save->delay_pair->i2, 0);
+
+ free (save);
+
+ for (save = backtrack_queue; save; save = save->next)
+ {
+ mark_backtrack_feeds (save->delay_pair->i2, 1);
+ }
+}
+
+/* Discard all data associated with the topmost entry in the backtrack
+ queue. If RESET_TICK is false, we just want to free the data. If true,
+ we are doing this because we discovered a reason to backtrack. In the
+ latter case, also reset the INSN_TICK for the shadow insn. */
+static void
+free_topmost_backtrack_point (bool reset_tick)
+{
+ struct haifa_saved_data *save = backtrack_queue;
+ int i;
+
+ backtrack_queue = save->next;
+
+ if (reset_tick)
+ {
+ struct delay_pair *pair = save->delay_pair;
+ while (pair)
+ {
+ INSN_TICK (pair->i2) = INVALID_TICK;
+ INSN_EXACT_TICK (pair->i2) = INVALID_TICK;
+ pair = pair->next_same_i1;
+ }
+ }
+ if (targetm.sched.free_sched_context)
+ targetm.sched.free_sched_context (save->be_saved_data);
+ if (current_sched_info->restore_state)
+ free (save->fe_saved_data);
+ for (i = 0; i <= max_insn_queue_index; i++)
+ free_INSN_LIST_list (&save->insn_queue[i]);
+ free (save->insn_queue);
+ free (save->curr_state);
+ free (save->ready.vec);
+ free (save);
+}
+
+/* Free the entire backtrack queue. */
+static void
+free_backtrack_queue (void)
+{
+ while (backtrack_queue)
+ free_topmost_backtrack_point (false);
+}
+
+/* Compute INSN_TICK_ESTIMATE for INSN. PROCESSED is a bitmap of
+ instructions we've previously encountered, a set bit prevents
+ recursion. BUDGET is a limit on how far ahead we look, it is
+ reduced on recursive calls. Return true if we produced a good
+ estimate, or false if we exceeded the budget. */
+static bool
+estimate_insn_tick (bitmap processed, rtx insn, int budget)
+{
+ sd_iterator_def sd_it;
+ dep_t dep;
+ int earliest = INSN_TICK (insn);
+
+ FOR_EACH_DEP (insn, SD_LIST_BACK, sd_it, dep)
+ {
+ rtx pro = DEP_PRO (dep);
+ int t;
+
+ if (QUEUE_INDEX (pro) == QUEUE_SCHEDULED)
+ gcc_assert (INSN_TICK (pro) + dep_cost (dep) <= INSN_TICK (insn));
+ else
+ {
+ int cost = dep_cost (dep);
+ if (cost >= budget)
+ return false;
+ if (!bitmap_bit_p (processed, INSN_LUID (pro)))
+ {
+ if (!estimate_insn_tick (processed, pro, budget - cost))
+ return false;
+ }
+ gcc_assert (INSN_TICK_ESTIMATE (pro) != INVALID_TICK);
+ t = INSN_TICK_ESTIMATE (pro) + cost;
+ if (earliest == INVALID_TICK || t > earliest)
+ earliest = t;
+ }
+ }
+ bitmap_set_bit (processed, INSN_LUID (insn));
+ INSN_TICK_ESTIMATE (insn) = earliest;
+ return true;
+}
+
+/* Examine the pair of insns in P, and estimate (optimistically, assuming
+ infinite resources) the cycle in which the delayed shadow can be issued.
+ Return the number of cycles that must pass before the real insn can be
+ issued in order to meet this constraint. */
+static int
+estimate_shadow_tick (struct delay_pair *p)
+{
+ bitmap_head processed;
+ int t;
+ bool cutoff;
+ bitmap_initialize (&processed, 0);
+
+ cutoff = !estimate_insn_tick (&processed, p->i2,
+ max_insn_queue_index + pair_delay (p));
+ bitmap_clear (&processed);
+ if (cutoff)
+ return max_insn_queue_index;
+ t = INSN_TICK_ESTIMATE (p->i2) - (clock_var + pair_delay (p) + 1);
+ if (t > 0)
+ return t;
+ return 0;
+}
/* Return the head and tail pointers of ebb starting at BEG and ending
at END. */
function max_issue. */
static struct choice_entry *choice_stack;
-/* The following variable value is number of essential insns issued on
- the current cycle. An insn is essential one if it changes the
- processors state. */
-int cycle_issued_insns;
-
/* This holds the value of the target dfa_lookahead hook. */
int dfa_lookahead;
issued in this cycle. TEMP_STATE is temporary scheduler state we
can use as scratch space. If FIRST_CYCLE_INSN_P is true, no insns
have been issued for the current cycle, which means it is valid to
- issue an asm statement. */
+ issue an asm statement.
+
+ If SHADOWS_ONLY_P is true, we eliminate all real insns and only
+ leave those for which SHADOW_P is true.
+
+ Return the number of cycles we must
+ advance to find the next ready instruction, or zero if there remain
+ insns on the ready list. */
static void
-prune_ready_list (state_t temp_state, bool first_cycle_insn_p)
+prune_ready_list (state_t temp_state, bool first_cycle_insn_p,
+ bool shadows_only_p)
{
int i;
int cost = 0;
const char *reason = "resource conflict";
- if (recog_memoized (insn) < 0)
+ if (shadows_only_p && !DEBUG_INSN_P (insn) && !SHADOW_P (insn))
+ {
+ cost = 1;
+ reason = "not a shadow";
+ }
+ else if (recog_memoized (insn) < 0)
{
if (!first_cycle_insn_p
&& (GET_CODE (PATTERN (insn)) == ASM_INPUT
cost = 0;
else
{
+ int delay_cost = 0;
+
+ if (delay_htab)
+ {
+ struct delay_pair *delay_entry;
+ delay_entry
+ = (struct delay_pair *)htab_find_with_hash (delay_htab, insn,
+ htab_hash_pointer (insn));
+ while (delay_entry && delay_cost == 0)
+ {
+ delay_cost = estimate_shadow_tick (delay_entry);
+ if (delay_cost > max_insn_queue_index)
+ delay_cost = max_insn_queue_index;
+ delay_entry = delay_entry->next_same_i1;
+ }
+ }
+
memcpy (temp_state, curr_state, dfa_state_size);
cost = state_transition (temp_state, insn);
if (cost < 0)
cost = 0;
else if (cost == 0)
cost = 1;
+ if (cost < delay_cost)
+ {
+ cost = delay_cost;
+ reason = "shadow tick";
+ }
}
if (cost >= 1)
{
}
}
+/* Called when we detect that the schedule is impossible. We examine the
+ backtrack queue to find the earliest insn that caused this condition. */
+
+static struct haifa_saved_data *
+verify_shadows (void)
+{
+ struct haifa_saved_data *save, *earliest_fail = NULL;
+ for (save = backtrack_queue; save; save = save->next)
+ {
+ int t;
+ struct delay_pair *pair = save->delay_pair;
+ rtx i1 = pair->i1;
+
+ for (; pair; pair = pair->next_same_i1)
+ {
+ rtx i2 = pair->i2;
+
+ if (QUEUE_INDEX (i2) == QUEUE_SCHEDULED)
+ continue;
+
+ t = INSN_TICK (i1) + pair_delay (pair);
+ if (t < clock_var)
+ {
+ if (sched_verbose >= 2)
+ fprintf (sched_dump,
+ ";;\t\tfailed delay requirements for %d/%d (%d->%d)"
+ ", not ready\n",
+ INSN_UID (pair->i1), INSN_UID (pair->i2),
+ INSN_TICK (pair->i1), INSN_EXACT_TICK (pair->i2));
+ earliest_fail = save;
+ break;
+ }
+ if (QUEUE_INDEX (i2) >= 0)
+ {
+ int queued_for = INSN_TICK (i2);
+
+ if (t < queued_for)
+ {
+ if (sched_verbose >= 2)
+ fprintf (sched_dump,
+ ";;\t\tfailed delay requirements for %d/%d"
+ " (%d->%d), queued too late\n",
+ INSN_UID (pair->i1), INSN_UID (pair->i2),
+ INSN_TICK (pair->i1), INSN_EXACT_TICK (pair->i2));
+ earliest_fail = save;
+ break;
+ }
+ }
+ }
+ }
+
+ return earliest_fail;
+}
+
/* Use forward list scheduling to rearrange insns of block pointed to by
TARGET_BB, possibly bringing insns from subsequent blocks in the same
region. */
haifa_recovery_bb_recently_added_p = false;
+ backtrack_queue = NULL;
+
/* Debug info. */
if (sched_verbose)
dump_new_block_header (0, *target_bb, head, tail);
gcc_assert (VEC_length (rtx, scheduled_insns) == 0);
sort_p = TRUE;
+ must_backtrack = false;
+
/* Loop until all the insns in BB are scheduled. */
while ((*current_sched_info->schedule_more_p) ())
{
while (advance > 0);
if (ready.n_ready > 0)
- prune_ready_list (temp_state, true);
+ prune_ready_list (temp_state, true, false);
if (ready.n_ready == 0)
continue;
+ if (must_backtrack)
+ goto do_backtrack;
ls.first_cycle_insn_p = true;
+ ls.shadows_only_p = false;
cycle_issued_insns = 0;
ls.can_issue_more = issue_rate;
for (;;)
{
rtx insn;
int cost;
- bool asm_p = false;
+ bool asm_p;
if (sort_p && ready.n_ready > 0)
{
if (ls.first_cycle_insn_p && !ready.n_ready)
break;
+ resume_after_backtrack:
/* Allow the target to reorder the list, typically for
better instruction bundling. */
if (sort_p
goto restart_choose_ready;
}
+ if (delay_htab)
+ {
+ /* If this insn is the first part of a delay-slot pair, record a
+ backtrack point. */
+ struct delay_pair *delay_entry;
+ delay_entry
+ = (struct delay_pair *)htab_find_with_hash (delay_htab, insn,
+ htab_hash_pointer (insn));
+ if (delay_entry)
+ {
+ save_backtrack_point (delay_entry, ls);
+ if (sched_verbose >= 2)
+ fprintf (sched_dump, ";;\t\tsaving backtrack point\n");
+ }
+ }
+
/* DECISION is made. */
if (TODO_SPEC (insn) & SPECULATIVE)
ls.can_issue_more--;
advance = schedule_insn (insn);
+ if (SHADOW_P (insn))
+ ls.shadows_only_p = true;
+
/* After issuing an asm insn we should start a new cycle. */
if (advance == 0 && asm_p)
advance = 1;
+
+ if (must_backtrack)
+ break;
+
if (advance != 0)
break;
ls.first_cycle_insn_p = false;
if (ready.n_ready > 0)
- prune_ready_list (temp_state, false);
+ prune_ready_list (temp_state, false, ls.shadows_only_p);
}
- }
+ do_backtrack:
+ if (!must_backtrack)
+ for (i = 0; i < ready.n_ready; i++)
+ {
+ rtx insn = ready_element (&ready, i);
+ if (INSN_EXACT_TICK (insn) == clock_var)
+ {
+ must_backtrack = true;
+ clock_var++;
+ break;
+ }
+ }
+ while (must_backtrack)
+ {
+ struct haifa_saved_data *failed;
+ rtx failed_insn;
+
+ must_backtrack = false;
+ failed = verify_shadows ();
+ gcc_assert (failed);
+
+ failed_insn = failed->delay_pair->i1;
+ unschedule_insns_until (failed_insn);
+ while (failed != backtrack_queue)
+ free_topmost_backtrack_point (true);
+ restore_last_backtrack_point (&ls);
+ if (sched_verbose >= 2)
+ fprintf (sched_dump, ";;\t\trewind to cycle %d\n", clock_var);
+ /* Delay by at least a cycle. This could cause additional
+ backtracking. */
+ queue_insn (failed_insn, 1, "backtracked");
+ advance = 0;
+ if (must_backtrack)
+ continue;
+ if (ready.n_ready > 0)
+ goto resume_after_backtrack;
+ else
+ {
+ if (clock_var == 0 && ls.first_cycle_insn_p)
+ goto end_schedule;
+ advance = 1;
+ break;
+ }
+ }
+ }
+ end_schedule:
/* Debug info. */
if (sched_verbose)
{
current_sched_info->head = head;
current_sched_info->tail = tail;
+
+ free_backtrack_queue ();
}
\f
/* Set_priorities: compute priority of each insn in the block. */
init_alias_analysis ();
- df_set_flags (DF_LR_RUN_DCE);
+ if (!sched_no_dce)
+ df_set_flags (DF_LR_RUN_DCE);
df_note_add_problem ();
/* More problems needed for interloop dep calculation in SMS. */
#endif
}
+/* Free all delay_pair structures that were recorded. */
+void
+free_delay_pairs (void)
+{
+ if (delay_htab)
+ {
+ htab_empty (delay_htab);
+ htab_empty (delay_htab_i2);
+ }
+}
+
/* Fix INSN_TICKs of the instructions in the current block as well as
INSN_TICKs of their dependents.
HEAD and TAIL are the begin and the end of the current scheduled block. */
INSN_COST (insn) = -1;
QUEUE_INDEX (insn) = QUEUE_NOWHERE;
INSN_TICK (insn) = INVALID_TICK;
+ INSN_EXACT_TICK (insn) = INVALID_TICK;
INTER_TICK (insn) = INVALID_TICK;
TODO_SPEC (insn) = HARD_DEP;
}
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