+/* Calculate MUST_PRECEDE/MUST_FOLLOW bitmaps of U_NODE; which is the
+ node currently been scheduled. At the end of the calculation
+ MUST_PRECEDE/MUST_FOLLOW contains all predecessors/successors of
+ U_NODE which are (1) already scheduled in the first/last row of
+ U_NODE's scheduling window, (2) whose dependence inequality with U
+ becomes an equality when U is scheduled in this same row, and (3)
+ whose dependence latency is zero.
+
+ The first and last rows are calculated using the following parameters:
+ START/END rows - The cycles that begins/ends the traversal on the window;
+ searching for an empty cycle to schedule U_NODE.
+ STEP - The direction in which we traverse the window.
+ II - The initiation interval. */
+
+static void
+calculate_must_precede_follow (ddg_node_ptr u_node, int start, int end,
+ int step, int ii, sbitmap sched_nodes,
+ sbitmap must_precede, sbitmap must_follow)
+{
+ ddg_edge_ptr e;
+ int first_cycle_in_window, last_cycle_in_window;
+
+ gcc_assert (must_precede && must_follow);
+
+ /* Consider the following scheduling window:
+ {first_cycle_in_window, first_cycle_in_window+1, ...,
+ last_cycle_in_window}. If step is 1 then the following will be
+ the order we traverse the window: {start=first_cycle_in_window,
+ first_cycle_in_window+1, ..., end=last_cycle_in_window+1},
+ or {start=last_cycle_in_window, last_cycle_in_window-1, ...,
+ end=first_cycle_in_window-1} if step is -1. */
+ first_cycle_in_window = (step == 1) ? start : end - step;
+ last_cycle_in_window = (step == 1) ? end - step : start;
+
+ sbitmap_zero (must_precede);
+ sbitmap_zero (must_follow);
+
+ if (dump_file)
+ fprintf (dump_file, "\nmust_precede: ");
+
+ /* Instead of checking if:
+ (SMODULO (SCHED_TIME (e->src), ii) == first_row_in_window)
+ && ((SCHED_TIME (e->src) + e->latency - (e->distance * ii)) ==
+ first_cycle_in_window)
+ && e->latency == 0
+ we use the fact that latency is non-negative:
+ SCHED_TIME (e->src) - (e->distance * ii) <=
+ SCHED_TIME (e->src) + e->latency - (e->distance * ii)) <=
+ first_cycle_in_window
+ and check only if
+ SCHED_TIME (e->src) - (e->distance * ii) == first_cycle_in_window */
+ for (e = u_node->in; e != 0; e = e->next_in)
+ if (TEST_BIT (sched_nodes, e->src->cuid)
+ && ((SCHED_TIME (e->src) - (e->distance * ii)) ==
+ first_cycle_in_window))
+ {
+ if (dump_file)
+ fprintf (dump_file, "%d ", e->src->cuid);
+
+ SET_BIT (must_precede, e->src->cuid);
+ }
+
+ if (dump_file)
+ fprintf (dump_file, "\nmust_follow: ");
+
+ /* Instead of checking if:
+ (SMODULO (SCHED_TIME (e->dest), ii) == last_row_in_window)
+ && ((SCHED_TIME (e->dest) - e->latency + (e->distance * ii)) ==
+ last_cycle_in_window)
+ && e->latency == 0
+ we use the fact that latency is non-negative:
+ SCHED_TIME (e->dest) + (e->distance * ii) >=
+ SCHED_TIME (e->dest) - e->latency + (e->distance * ii)) >=
+ last_cycle_in_window
+ and check only if
+ SCHED_TIME (e->dest) + (e->distance * ii) == last_cycle_in_window */
+ for (e = u_node->out; e != 0; e = e->next_out)
+ if (TEST_BIT (sched_nodes, e->dest->cuid)
+ && ((SCHED_TIME (e->dest) + (e->distance * ii)) ==
+ last_cycle_in_window))
+ {
+ if (dump_file)
+ fprintf (dump_file, "%d ", e->dest->cuid);
+
+ SET_BIT (must_follow, e->dest->cuid);
+ }
+
+ if (dump_file)
+ fprintf (dump_file, "\n");
+}
+
+/* Return 1 if U_NODE can be scheduled in CYCLE. Use the following
+ parameters to decide if that's possible:
+ PS - The partial schedule.
+ U - The serial number of U_NODE.
+ NUM_SPLITS - The number of row splits made so far.
+ MUST_PRECEDE - The nodes that must precede U_NODE. (only valid at
+ the first row of the scheduling window)
+ MUST_FOLLOW - The nodes that must follow U_NODE. (only valid at the
+ last row of the scheduling window) */
+
+static bool
+try_scheduling_node_in_cycle (partial_schedule_ptr ps, ddg_node_ptr u_node,
+ int u, int cycle, sbitmap sched_nodes,
+ int *num_splits, sbitmap must_precede,
+ sbitmap must_follow)
+{
+ ps_insn_ptr psi;
+ bool success = 0;
+
+ verify_partial_schedule (ps, sched_nodes);
+ psi = ps_add_node_check_conflicts (ps, u_node, cycle,
+ must_precede, must_follow);
+ if (psi)
+ {
+ SCHED_TIME (u_node) = cycle;
+ SET_BIT (sched_nodes, u);
+ success = 1;
+ *num_splits = 0;
+ if (dump_file)
+ fprintf (dump_file, "Scheduled w/o split in %d\n", cycle);
+
+ }
+
+ return success;
+}
+
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