From: Matthias Braun <matze@braunis.de>
Date: Thu, 3 Mar 2011 13:29:51 +0000 (+0100)
Subject: remove mostly unused/broken liveness tracking in scheduler
X-Git-Url: http://nsz.repo.hu/git/?a=commitdiff_plain;h=f8f2653ab58755a60aa9b4a9f226343687d1bc90;p=libfirm

remove mostly unused/broken liveness tracking in scheduler
---

diff --git a/ir/be/belistsched.c b/ir/be/belistsched.c
index 5a2aaa6f2..d38fd4253 100644
--- a/ir/be/belistsched.c
+++ b/ir/be/belistsched.c
@@ -87,7 +87,6 @@ typedef struct block_sched_env_t {
 	ir_nodeset_t cands;                         /**< the set of candidates */
 	ir_node *block;                             /**< the current block */
 	sched_env_t *sched_env;                     /**< the scheduler environment */
-	ir_nodeset_t live;                          /**< simple liveness during scheduling */
 	const list_sched_selector_t *selector;
 	void *selector_block_env;
 } block_sched_env_t;
@@ -231,76 +230,6 @@ static inline int add_irn_not_sched_user(block_sched_env_t *env, ir_node *n, int
 	return env->sched_info[idx].num_not_sched_user;
 }
 
-/**
- * Returns the number of users of a node having mode datab.
- */
-static int get_num_successors(ir_node *irn)
-{
-	int             sum = 0;
-	const ir_edge_t *edge;
-
-	if (get_irn_mode(irn) == mode_T) {
-		/* for mode_T nodes: count the users of all Projs */
-		foreach_out_edge(irn, edge) {
-			ir_node *proj = get_edge_src_irn(edge);
-			ir_mode *mode = get_irn_mode(proj);
-
-			if (mode == mode_T) {
-				sum += get_num_successors(proj);
-			} else if (mode_is_datab(mode)) {
-				sum += get_irn_n_edges(proj);
-			}
-		}
-	}
-	else {
-		/* do not count keep-alive edges */
-		foreach_out_edge(irn, edge) {
-			if (get_irn_opcode(get_edge_src_irn(edge)) != iro_End)
-				sum++;
-		}
-	}
-
-	return sum;
-}
-
-/**
- * Adds irn to @p live, updates all inputs that this user is scheduled
- * and counts all of its non scheduled users.
- */
-static void update_sched_liveness(block_sched_env_t *env, ir_node *irn)
-{
-	int i;
-
-	/* ignore Projs */
-	if (is_Proj(irn))
-		return;
-
-	for (i = get_irn_ins_or_deps(irn) - 1; i >= 0; --i) {
-		ir_node *in = get_irn_in_or_dep(irn, i);
-
-		/* if in is a proj: update predecessor */
-		in = skip_Proj(in);
-
-		/* if in is still in the live set: reduce number of users by one */
-		if (ir_nodeset_contains(&env->live, in)) {
-			if (add_irn_not_sched_user(env, in, -1) <= 0)
-				ir_nodeset_remove(&env->live, in);
-		}
-	}
-
-	/*
-		get_num_successors returns the number of all users. This includes
-		users in different blocks as well. As the each block is scheduled separately
-		the liveness info of those users will not be updated and so these
-		users will keep up the register pressure as it is desired.
-	*/
-	i = get_num_successors(irn);
-	if (i > 0) {
-		set_irn_not_sched_user(env, irn, i);
-		ir_nodeset_insert(&env->live, irn);
-	}
-}
-
 static void selected(block_sched_env_t *env, ir_node *node)
 {
 	/* notify the selector about the finally selected node. */
@@ -323,7 +252,6 @@ static void add_to_sched(block_sched_env_t *env, ir_node *irn)
 {
 	assert(! (arch_irn_get_flags(irn) & arch_irn_flags_not_scheduled));
 
-	update_sched_liveness(env, irn);
 	sched_add_before(env->block, irn);
 
 	DBG((dbg, LEVEL_2, "\tadding %+F\n", irn));
@@ -362,7 +290,6 @@ static void list_sched_block(ir_node *block, void *env_ptr)
 	be.sched_info = env->sched_info;
 	be.block      = block;
 	ir_nodeset_init_size(&be.cands, get_irn_n_edges(block));
-	ir_nodeset_init_size(&be.live, get_irn_n_edges(block));
 	be.selector   = selector;
 	be.sched_env  = env;
 
@@ -412,9 +339,6 @@ static void list_sched_block(ir_node *block, void *env_ptr)
 				if (get_nodes_block(operand) == block) {
 					ready = 0;
 					break;
-				} else {
-					/* live in values increase register pressure */
-					ir_nodeset_insert(&be.live, operand);
 				}
 			}
 
@@ -438,7 +362,7 @@ static void list_sched_block(ir_node *block, void *env_ptr)
 		}
 
 		if (irn == NULL) {
-			irn = be.selector->select(be.selector_block_env, &be.cands, &be.live);
+			irn = be.selector->select(be.selector_block_env, &be.cands);
 		}
 
 		DB((dbg, LEVEL_2, "\tpicked node %+F\n", irn));
@@ -454,7 +378,6 @@ static void list_sched_block(ir_node *block, void *env_ptr)
 		selector->finish_block(be.selector_block_env);
 
 	ir_nodeset_destroy(&be.cands);
-	ir_nodeset_destroy(&be.live);
 }
 
 /* List schedule a graph. */
diff --git a/ir/be/belistsched.h b/ir/be/belistsched.h
index e7ff9d75b..387b6d730 100644
--- a/ir/be/belistsched.h
+++ b/ir/be/belistsched.h
@@ -71,11 +71,9 @@ typedef struct list_sched_selector_t {
 	 * @param block_env   Some private information as returned by init_block().
 	 * @param sched_head  The schedule so far.
 	 * @param ready_set   A set containing all ready nodes. Pick one of these nodes.
-	 * @param live_set    A set containing all nodes currently alive.
 	 * @return The chosen node.
 	 */
-	ir_node *(*select)(void *block_env, ir_nodeset_t *ready_set,
-                       ir_nodeset_t *live_set);
+	ir_node *(*select)(void *block_env, ir_nodeset_t *ready_set);
 
 	/**
 	 * This function gets executed after a node finally has been made ready.
diff --git a/ir/be/beschednormal.c b/ir/be/beschednormal.c
index 68ae8b555..09ad7e25f 100644
--- a/ir/be/beschednormal.c
+++ b/ir/be/beschednormal.c
@@ -54,8 +54,7 @@ static int must_be_scheduled(const ir_node* const irn)
 }
 
 
-static ir_node *normal_select(void *block_env, ir_nodeset_t *ready_set,
-                              ir_nodeset_t *live_set)
+static ir_node *normal_select(void *block_env, ir_nodeset_t *ready_set)
 {
 	instance_t* inst = (instance_t*)block_env;
 	ir_node*    irn;
@@ -63,8 +62,6 @@ static ir_node *normal_select(void *block_env, ir_nodeset_t *ready_set,
 	ir_node*    last = NULL;
 	ir_nodeset_iterator_t iter;
 
-	(void)live_set;
-
 	for (irn = inst->curr_list; irn != NULL; last = irn, irn = next) {
 		next = (ir_node*)get_irn_link(irn);
 		if (ir_nodeset_contains(ready_set, irn)) {
diff --git a/ir/be/beschedrand.c b/ir/be/beschedrand.c
index 6472228d6..9108f1f88 100644
--- a/ir/be/beschedrand.c
+++ b/ir/be/beschedrand.c
@@ -36,14 +36,12 @@
  * The random selector:
  * Just assure that branches are executed last, otherwise select a random node
  */
-static ir_node *random_select(void *block_env, ir_nodeset_t *ready_set,
-                              ir_nodeset_t *live_set)
+static ir_node *random_select(void *block_env, ir_nodeset_t *ready_set)
 {
 	ir_nodeset_iterator_t iter;
 	ir_node          *irn      = NULL;
 	int only_branches_left = 1;
 	(void)block_env;
-	(void)live_set;
 
 	/* assure that branches and constants are executed last */
 	ir_nodeset_iterator_init(&iter, ready_set);
diff --git a/ir/be/beschedregpress.c b/ir/be/beschedregpress.c
index af0b62192..8fba2fd93 100644
--- a/ir/be/beschedregpress.c
+++ b/ir/be/beschedregpress.c
@@ -257,14 +257,12 @@ static inline int reg_pr_costs(reg_pressure_selector_env_t *env, ir_node *irn)
 	return sum;
 }
 
-static ir_node *reg_pressure_select(void *block_env, ir_nodeset_t *ready_set,
-                                    ir_nodeset_t *live_set)
+static ir_node *reg_pressure_select(void *block_env, ir_nodeset_t *ready_set)
 {
 	ir_nodeset_iterator_t iter;
 	reg_pressure_selector_env_t *env = (reg_pressure_selector_env_t*)block_env;
 	ir_node *irn, *res     = NULL;
 	int curr_cost          = INT_MAX;
-	(void) live_set;
 
 	assert(ir_nodeset_size(ready_set) > 0);
 
diff --git a/ir/be/beschedtrace.c b/ir/be/beschedtrace.c
index 8c31a44ad..58e7604dc 100644
--- a/ir/be/beschedtrace.c
+++ b/ir/be/beschedtrace.c
@@ -570,14 +570,13 @@ static ir_node *basic_selection(ir_nodeset_t *ready_set)
 /**
 * The muchnik selector.
 */
-static ir_node *muchnik_select(void *block_env, ir_nodeset_t *ready_set, ir_nodeset_t *live_set)
+static ir_node *muchnik_select(void *block_env, ir_nodeset_t *ready_set)
 {
 	trace_env_t *env = (trace_env_t*)block_env;
 	ir_nodeset_t mcands, ecands;
 	ir_nodeset_iterator_t iter;
 	sched_timestep_t max_delay = 0;
 	ir_node *irn;
-	(void) live_set;
 
 	/* calculate the max delay of all candidates */
 	foreach_ir_nodeset(ready_set, irn, iter) {
@@ -658,15 +657,18 @@ static void sched_muchnik(ir_graph *irg)
 /**
  * Execute the heuristic function.
  */
-static ir_node *heuristic_select(void *block_env, ir_nodeset_t *ns, ir_nodeset_t *lv)
+static ir_node *heuristic_select(void *block_env, ir_nodeset_t *ns)
 {
 	trace_env_t *trace_env   = (trace_env_t*)block_env;
 	ir_node     *irn, *cand  = NULL;
 	int         max_prio     = INT_MIN;
 	int         cur_prio     = INT_MIN;
-	int         cur_pressure = ir_nodeset_size(lv);
 	int         reg_fact, cand_reg_fact;
 	ir_nodeset_iterator_t iter;
+	/* Note: register pressure calculation needs an overhaul, you need correct
+	 * tracking for each register class indidually and weight by each class
+	int         cur_pressure = ir_nodeset_size(lv); */
+	int         cur_pressure = 1;
 
 	/* prefer instructions which can be scheduled early */
 #define PRIO_TIME        3
@@ -689,7 +691,6 @@ static ir_node *heuristic_select(void *block_env, ir_nodeset_t *ns, ir_nodeset_t
 			int sign  = rdiff < 0;
 			int chg   = (rdiff < 0 ? -rdiff : rdiff) << PRIO_CHG_PRESS;
 
-			/* reg_fact = chg << cur_pressure; */
 			reg_fact = chg * cur_pressure;
 			if (reg_fact < chg)
 				reg_fact = INT_MAX - 2;
diff --git a/ir/be/beschedtrivial.c b/ir/be/beschedtrivial.c
index 6d272ccbe..d05a0a98e 100644
--- a/ir/be/beschedtrivial.c
+++ b/ir/be/beschedtrivial.c
@@ -42,13 +42,11 @@
  * Just assure that branches are executed last, otherwise select
  * the first node ready.
  */
-static ir_node *trivial_select(void *block_env, ir_nodeset_t *ready_set,
-                               ir_nodeset_t *live_set)
+static ir_node *trivial_select(void *block_env, ir_nodeset_t *ready_set)
 {
 	ir_node               *irn;
 	ir_nodeset_iterator_t  iter;
 	(void)block_env;
-	(void)live_set;
 
 	/* assure that branches and constants are executed last */
 	foreach_ir_nodeset(ready_set, irn, iter) {