/*
- * Copyright (C) 1995-2007 University of Karlsruhe. All right reserved.
+ * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
*
* This file is part of libFirm.
*
#include "ircons_t.h"
#include "irprintf.h"
#include "execfreq.h"
+#include "dfs_t.h"
#include "xmalloc.h"
#include "beutil.h"
#include "bearch_t.h"
-#include "bespillbelady.h"
#include "besched_t.h"
#include "beirgmod.h"
#include "belive_t.h"
#include "beloopana.h"
#include "beirg_t.h"
#include "bemodule.h"
+#include "bespill.h"
+
+#include "lc_opts.h"
+#include "lc_opts_enum.h"
#define DBG_SPILL 1
#define DBG_WSETS 2
#define DBG_WORKSET 128
#define DBG_GLOBAL 256
-#define DEAD UINT_MAX
-#define LIVE_END (DEAD-1)
+#define ALREADY_SPILLED_FACTOR 2
+
+#define DEAD UINT_MAX
+#define LIVE_END (DEAD-1)
+#define REMAT_DIST (DEAD-2)
+
+static int already_spilled_factor = 2;
+static int remat_live_range_ext = 1;
+static int global_pass_enabled = 1;
+
+static const lc_opt_table_entry_t options[] = {
+ LC_OPT_ENT_INT ("asf", "already spilled factor", &already_spilled_factor),
+ LC_OPT_ENT_BOOL ("remat", "rematerializable ops get infinite long live ranges", &remat_live_range_ext),
+ LC_OPT_ENT_BOOL ("global", "enable/disable the global pass", &global_pass_enabled),
+ LC_OPT_LAST
+};
DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
typedef struct _belady_env_t {
struct obstack ob;
ir_graph *irg;
+ const dfs_t *dfs;
const arch_env_t *arch;
const arch_register_class_t *cls;
be_lv_t *lv;
ir_exec_freq *ef;
- ir_node **blocks; /**< Array of all blocks. */
- int n_blocks; /**< Number of blocks in the graph. */
- int n_regs; /**< number of regs in this reg-class */
- workset_t *ws; /**< the main workset used while processing a block. ob-allocated */
- ir_node *instr; /**< current instruction */
- unsigned instr_nr; /**< current instruction number (relative to block start) */
+ ir_node **blocks; /**< Array of all blocks. */
+ int n_blocks; /**< Number of blocks in the graph. */
+ int n_regs; /**< number of regs in this reg-class */
+ workset_t *ws; /**< the main workset used while processing a block. ob-allocated */
+ ir_node *instr; /**< current instruction */
+ int instr_nr; /**< current instruction number (relative to block start) */
- spill_env_t *senv; /**< see bespill.h */
+ spill_env_t *senv; /**< see bespill.h */
+ bitset_t *spilled; /**< bitset to keep all the irns which have already been spilled. */
+ ir_nodeset_t *extra_spilled; /** All nodes for which a special spill location has been computed. */
} belady_env_t;
int i;
/* check for current regclass */
if (!arch_irn_consider_in_reg_alloc(env->arch, env->cls, val)) {
- DBG((dbg, DBG_WORKSET, "Skipped %+F\n", val));
+ // DBG((dbg, DBG_WORKSET, "Skipped %+F\n", val));
return;
}
#define workset_sort(ws) qsort((ws)->vals, (ws)->len, sizeof((ws)->vals[0]), loc_compare);
#define workset_contains(ws, n) (workset_get_index(ws, n) >= 0)
+typedef struct _bring_in_t bring_in_t;
+
typedef struct _block_info_t {
belady_env_t *bel;
- const ir_node *bl;
- workset_t *ws_start, *ws_end;
- ir_phase next_uses;
+ ir_node *bl;
int id;
+ ir_phase next_uses;
+ workset_t *ws_end; /**< The end set after the local belady pass. */
+ double exec_freq; /**< The execution frequency of this block. */
+ double reload_cost; /**< Cost of a reload in this block. */
ir_node *first_non_in; /**< First node in block which is not a phi. */
ir_node *last_ins; /**< The instruction before which end of
block reloads will be inserted. */
- workset_t *entrance_reg; /**< That set will contain all values
- transported into the block which
- are used before they are displaced.
- That means, we later have to care to
- bring them into the block in a register
- or reload them at the entry of the block. */
+ int pressure; /**< The amount of registers which remain free
+ in this block. This capacity can be used to let
+ global variables, transported into other blocks,
+ live through this block. */
- int pressure; /**< The amount of registers which remain free
- in this block. This capacity can be used to let
- global variables, transported into other blocks,
- live through this block. */
+ int front_pressure; /**< The pressure right before the first
+ real (non-phi) node. At the beginning
+ of the global pass, this is 0. */
+ struct list_head br_head; /**< List head for all bring_in variables. */
+ int free_at_jump; /**< registers free at jump. */
- double exec_freq; /**< The execution frequency of this block. */
} block_info_t;
static INLINE void *new_block_info(belady_env_t *bel, int id)
res->bel = bel;
res->bl = bl;
res->id = id;
- res->entrance_reg = new_workset(bel, &bel->ob);
res->exec_freq = get_block_execfreq(bel->ef, bl);
+ res->reload_cost = bel->arch->isa->reload_cost * res->exec_freq;
+ res->free_at_jump = bel->n_regs;
+ INIT_LIST_HEAD(&res->br_head);
set_irn_link(bl, res);
return res;
}
in the block. Needed to identify
transport in values for the global
pass. */
- int step; /**< The time step of the use. */
+ sched_timestep_t step; /**< The time step of the use. */
+ ir_node *irn;
struct _next_use_t *next; /**< The next use int this block
or NULL. */
} next_use_t;
-static void *next_use_init(ir_phase *phase, ir_node *irn, void *old)
+static void *next_use_init(ir_phase *phase, const ir_node *irn, void *old)
{
(void) phase;
(void) irn;
{
ir_node *irn;
+ sched_renumber(bi->bl);
+
phase_init(&bi->next_uses, "next uses", bi->bel->irg, PHASE_DEFAULT_GROWTH, next_use_init, NULL);
sched_foreach_reverse(bi->bl, irn) {
- int i, step = sched_get_time_step(irn);
+ int i;
if (is_Phi(irn))
break;
next_use_t *curr = phase_get_irn_data(&bi->next_uses, op);
next_use_t *use = phase_alloc(&bi->next_uses, sizeof(use[0]));
- assert(step >= 0);
use->is_first_use = 1;
- use->step = step;
+ use->step = sched_get_time_step(irn);
use->next = curr;
+ use->irn = irn;
- if (curr)
+ if (curr) {
curr->is_first_use = 0;
+ assert(curr->step >= use->step);
+ }
phase_set_irn_data(&bi->next_uses, op, use);
}
phase_set_irn_data(&bi->next_uses, irn, use->next);
}
+static __attribute__((unused)) int block_freq_gt(const void *a, const void *b)
+{
+ const ir_node * const *p = a;
+ const ir_node * const *q = b;
+ block_info_t *pi = get_block_info(*p);
+ block_info_t *qi = get_block_info(*q);
+ double diff = qi->exec_freq - pi->exec_freq;
+ return (diff > 0) - (diff < 0);
+}
+
+static int block_freq_dfs_gt(const void *a, const void *b)
+{
+ const ir_node * const *p = a;
+ const ir_node * const *q = b;
+ block_info_t *pi = get_block_info(*p);
+ block_info_t *qi = get_block_info(*q);
+ double diff;
+
+ if ((pi->exec_freq > 1.0 && qi->exec_freq > 1.0)
+ || (pi->exec_freq <= 1.0 && qi->exec_freq <= 1.0)) {
+
+ const dfs_t *dfs = pi->bel->dfs;
+ int pp = dfs_get_post_num(dfs, pi->bl);
+ int pq = dfs_get_post_num(dfs, qi->bl);
+ return pq - pp;
+ }
+
+ diff = qi->exec_freq - pi->exec_freq;
+ return (diff > 0) - (diff < 0);
+}
+
+/*
+ ____ _ ___
+ | __ ) _ __(_)_ __ __ _ |_ _|_ __
+ | _ \| '__| | '_ \ / _` | | || '_ \
+ | |_) | | | | | | | (_| | | || | | |
+ |____/|_| |_|_| |_|\__, | |___|_| |_|
+ |___/
+
+ Data structures to represent bring in variables.
+*/
+
+struct _bring_in_t {
+ ir_node *irn; /**< The node to bring in. */
+ block_info_t *bi; /**< The block to which bring in should happen. */
+ int pressure_so_far; /**< The maximal pressure till the first use of irn in bl. */
+ ir_node *first_use; /**< The first user of irn in bl. */
+ sched_timestep_t use_step; /**< Schedule sttep of the first use. */
+
+ int is_remat : 1; /**< Is rematerializable. */
+ int sect_pressure; /**< Offset to maximum pressure in block. */
+ struct list_head list;
+ struct list_head sect_list;
+ bring_in_t *sect_head;
+};
+
+static INLINE bring_in_t *new_bring_in(block_info_t *bi, ir_node *irn, const next_use_t *use)
+{
+ bring_in_t *br = obstack_alloc(&bi->bel->ob, sizeof(br[0]));
+
+ br->irn = irn;
+ br->bi = bi;
+ br->first_use = use->irn;
+ br->use_step = use->step;
+ br->is_remat = be_is_rematerializable(bi->bel->senv, irn, use->irn);
+ br->pressure_so_far = bi->pressure;
+ br->sect_pressure = bi->front_pressure;
+ br->sect_head = br;
+
+ INIT_LIST_HEAD(&br->list);
+ INIT_LIST_HEAD(&br->sect_list);
+ list_add_tail(&br->list, &bi->br_head);
+ return br;
+}
+
+static int bring_in_cmp(const void *a, const void *b)
+{
+ const bring_in_t *p = *(const bring_in_t * const *) a;
+ const bring_in_t *q = *(const bring_in_t * const *) b;
+ double fp, fq;
+
+ /* if one of both is a remat node, it will be done after the other. */
+ if (p->is_remat != q->is_remat)
+ return p->is_remat - q->is_remat;
+
+ /* in the same block, the one further in the front has to be processed first!
+ * Otherwise the front_pressure 'trick' is not exact. */
+ if (p->bi == q->bi)
+ return p->use_step - q->use_step;
+
+ fp = p->bi->exec_freq;
+ fq = q->bi->exec_freq;
+
+ /* if both have the same frequency, inspect the frequency of the definition */
+ if (fp == fq) {
+ double fdp = get_block_info(get_nodes_block(p->irn))->exec_freq;
+ double fdq = get_block_info(get_nodes_block(q->irn))->exec_freq;
+
+ /* if the defs of both have the same freq, we go for reverse dfs post order. */
+ if (fdp == fdq) {
+ const dfs_t *dfs = p->bi->bel->dfs;
+ int pp = dfs_get_post_num(dfs, p->bi->bl);
+ int pq = dfs_get_post_num(dfs, q->bi->bl);
+ return pq - pp;
+ }
+
+ return (fdq > fdp) - (fdq < fdp);
+ }
+
+ return (fq > fp) - (fq < fp);
+}
+
static INLINE unsigned get_curr_distance(block_info_t *bi, const ir_node *irn, int is_usage)
{
- belady_env_t *env = bi->bel;
- next_use_t *use = get_current_use(bi, irn);
- int curr_step = sched_get_time_step(env->instr);
- int flags = arch_irn_get_flags(env->arch, irn);
+ belady_env_t *env = bi->bel;
+ sched_timestep_t curr_step = sched_get_time_step(env->instr);
+ next_use_t *use = get_current_use(bi, irn);
+ int flags = arch_irn_get_flags(env->arch, irn);
assert(!(flags & arch_irn_flags_ignore));
use = use->next;
if (use) {
+ unsigned res = use->step - curr_step;
+
assert(use->step >= curr_step);
- return use->step - curr_step;
+
+ if (res != 0) {
+ if (remat_live_range_ext && be_is_rematerializable(env->senv, irn, use->irn))
+ res = REMAT_DIST;
+ else if (bitset_contains_irn(env->spilled, irn))
+ res *= already_spilled_factor;
+ }
+
+ return res;
}
return be_is_live_end(env->lv, bi->bl, irn) ? LIVE_END : DEAD;
*/
static INLINE int is_transport_in(const ir_node *bl, const ir_node *irn)
{
- return is_local_phi(bl, irn) || get_nodes_block(irn) != bl;
+ return get_nodes_block(irn) != bl || is_Phi(irn);
}
/**
/* mark value as used */
if (! workset_contains(ws, val)) {
- DBG((dbg, DBG_DECIDE, " insert %+F\n", val));
+ DBG((dbg, DBG_DECIDE, "\t\tinsert %+F\n", val));
to_insert[demand++] = val;
if (is_usage) {
- int insert_reload = 1;
next_use_t *use = get_current_use(bi, val);
/*
* entrance to here or not.
*/
assert(use);
- assert(sched_get_time_step(env->instr) == use->step);
+ assert(sched_get_time_step(env->instr) == (int) use->step);
if (is_transport_in(bi->bl, val) && use->is_first_use) {
- DBG((dbg, DBG_DECIDE, "entrance node %+F, pressure %d:\n", val, bi->pressure));
- if (bi->pressure < env->n_regs) {
- workset_insert(env, bi->entrance_reg, val);
- insert_reload = 0;
- ++bi->pressure;
- DBG((dbg, DBG_DECIDE, "... no reload. must be considered at block start\n"));
- }
+ bring_in_t *bri = new_bring_in(bi, val, use);
+ bri->first_use = env->instr;
+
+ /* reset the section pressure, since a new section starts. */
+ bi->front_pressure = 0;
+
+ DBG((dbg, DBG_DECIDE, "\t\tbring in node %+F, pressure %d:\n", val, bi->pressure));
+ DBG((dbg, DBG_DECIDE, "\t\tno reload. must be considered at block start\n"));
}
- if (insert_reload) {
- DBG((dbg, DBG_SPILL, "Reload %+F before %+F\n", val, env->instr));
+ else {
+ bitset_add_irn(env->spilled, val);
+ DBG((dbg, DBG_SPILL, "\t\tReload %+F before %+F\n", val, env->instr));
be_add_reload(env->senv, val, env->instr, env->cls, 1);
}
}
} else {
- assert(is_usage || "Defined value already in workset?!?");
- DBG((dbg, DBG_DECIDE, " skip %+F\n", val));
+ assert(is_usage && "Defined value already in workset?!?");
+ DBG((dbg, DBG_DECIDE, "\t\tskip %+F\n", val));
}
}
- DBG((dbg, DBG_DECIDE, " demand = %d\n", demand));
+ DBG((dbg, DBG_DECIDE, "\t\tdemand = %d\n", demand));
/*
2. Make room for at least 'demand' slots
/* Only make more free room if we do not have enough */
if (len > max_allowed) {
- // int curr_step = sched_get_time_step(env->instr);
-
- DBG((dbg, DBG_DECIDE, " disposing %d values\n", len - max_allowed));
+ DBG((dbg, DBG_DECIDE, "\t\tdisposing %d values\n", len - max_allowed));
/* get current next-use distance */
for (i = 0; i < ws->len; ++i) {
for (i = 0; i < demand; ++i)
workset_insert(env, env->ws, to_insert[i]);
- bi->pressure = MAX(bi->pressure, workset_get_length(env->ws));
+ /* TODO: simplify this expression? */
+ bi->pressure = MAX(bi->pressure, workset_get_length(env->ws));
+ bi->front_pressure = MAX(bi->front_pressure, workset_get_length(env->ws));
}
/**
static void belady(belady_env_t *env, int id) {
block_info_t *block_info = new_block_info(env, id);
const ir_node *block = block_info->bl;
- void *obst_state = obstack_base(&env->ob);
workset_t *new_vals;
ir_node *irn;
int iter;
- DBG((dbg, DBG_WSETS, "Processing %+F...\n", block_info->bl));
+ DBG((dbg, DBG_WSETS, "Belady on %+F\n", block_info->bl));
new_vals = new_workset(env, &env->ob);
workset_clear(env->ws);
/* projs are handled with the tuple value.
* Phis are no real instr (see insert_starters())
* instr_nr does not increase */
- if (is_Proj(irn) || is_Phi(irn)) {
- DBG((dbg, DBG_DECIDE, " ...%+F skipped\n", irn));
+ if (is_Proj(irn) || is_Phi(irn))
continue;
- }
- DBG((dbg, DBG_DECIDE, " ...%+F\n", irn));
+ DBG((dbg, DBG_DECIDE, "\t%+F\n", irn));
if (!block_info->first_non_in)
block_info->first_non_in = irn;
for(i = 0, arity = get_irn_arity(irn); i < arity; ++i) {
workset_insert(env, new_vals, get_irn_n(irn, i));
}
+ DBG((dbg, DBG_DECIDE, "\t* uses\n"));
displace(block_info, new_vals, 1);
/*
} else {
workset_insert(env, new_vals, irn);
}
+ DBG((dbg, DBG_DECIDE, "\t* defs\n"));
displace(block_info, new_vals, 0);
+ if (is_op_forking(get_irn_op(env->instr))) {
+ for (i = get_irn_arity(env->instr) - 1; i >= 0; --i) {
+ ir_node *op = get_irn_n(env->instr, i);
+ block_info->free_at_jump -= arch_irn_consider_in_reg_alloc(env->arch, env->cls, op);
+ }
+ }
+
env->instr_nr++;
}
phase_free(&block_info->next_uses);
- obstack_free(&env->ob, obst_state);
/* Remember end-workset for this block */
block_info->ws_end = workset_clone(env, &env->ob, env->ws);
workset_foreach(block_info->ws_end, irn, iter)
DBG((dbg, DBG_WSETS, " %+F (%u)\n", irn, workset_get_time(block_info->ws_end, iter)));
DBG((dbg, DBG_WSETS, "Max pressure in block: %d\n", block_info->pressure));
+
+ /* now, initialize the front pressure to 0. */
+ block_info->front_pressure = 0;
}
/*
#define ver_is_older(v, w) ((v) < (w))
#define ver_is_younger(v, w) ((v) > (w))
-static int block_freq_gt(const void *a, const void *b)
-{
- const ir_node * const *p = a;
- const ir_node * const *q = b;
- block_info_t *pi = get_block_info(*p);
- block_info_t *qi = get_block_info(*q);
- double diff = qi->exec_freq - pi->exec_freq;
- return (diff > 0) - (diff < 0);
-}
-
enum {
irn_act_none = 0,
irn_act_reload,
struct _block_state_t *next;
struct _block_state_t *next_intern;
block_info_t *bi;
- unsigned pressure;
+ int pressure;
workset_t *end_state;
} block_state_t;
irn_action_t *ia_top;
} rollback_info_t;
-static INLINE block_state_t *get_block_state(global_end_state_t *ges, block_info_t *bi)
+static INLINE block_state_t *get_block_state(global_end_state_t *ges, const block_info_t *bi)
{
int id = bi->id;
assert(!ver_is_younger(ges->bs_tops_vers[id], ges->version));
*/
{
- int n_regs = bi->bel->n_regs;
+ int n_regs = bi->free_at_jump;
int len = workset_get_length(end);
int slot = -1;
int i;
workset_t *end = bs->end_state;
ir_node *ins_before = block_info_get_last_ins(bi);
double reload_here = be_get_reload_costs(bi->bel->senv, irn, ins_before);
- int pressure_ok = bs->pressure < (unsigned) n_regs;
+ int pressure_ok = bs->pressure < n_regs;
+
+ if (reload_here < bi->reload_cost)
+ reload_here = 0.0;
/*
* No matter what we do, the value will be in the end set
DBG((dbg, DBG_GLOBAL, "\t%2Dthere is a free slot. capacity=%d, reload here=%f, pressure %s\n",
level, n_regs - bs->pressure, reload_here, pressure_ok ? "ok" : "insufficient"));
+
/* look if we can bring the value in. */
- if (pressure_ok) {
+ if (pressure_ok && reload_here > 0.0) {
rollback_info_t rb = trans_begin(ges);
double new_limit = MIN(reload_here, limit);
}
}
+
DBG((dbg, DBG_GLOBAL, "\t%2D%s\n", level,
vs->act == irn_act_reload ? "reloading" : "bringing in"));
}
ir_node **nodes = alloca(get_irn_arity(bl) * sizeof(nodes[0]));
rollback_info_t rb = trans_begin(ges);
-
glob_costs = 0.0;
for (i = 0; i < n; ++i) {
ir_node *pr = get_Block_cfgpred_block(bl, i);
for (ia = ges->ia_top; ia != NULL; ia = ia->next) {
switch (ia->act) {
case irn_act_live_through:
- if (is_local_phi(ia->bl, ia->irn)) {
- bitset_add_irn(ges->succ_phis, ia->irn);
- DBG((dbg, DBG_GLOBAL, "\t\tlive through phi kept alive: %+F\n", ia->irn));
+ {
+ block_info_t *bi = get_block_info(ia->bl);
+ bring_in_t *iter;
+
+ if (is_local_phi(ia->bl, ia->irn)) {
+ bitset_add_irn(ges->succ_phis, ia->irn);
+ DBG((dbg, DBG_GLOBAL, "\t\tlive through phi kept alive: %+F\n", ia->irn));
+ }
+
+ list_for_each_entry_reverse(bring_in_t, iter, &bi->br_head, list)
+ ++iter->sect_pressure;
+ ++bi->front_pressure;
}
break;
case irn_act_reload:
bitset_clear_all(ges->committed);
}
+static ir_node *better_spilled_here(const bring_in_t *br)
+{
+ const block_info_t *bi = br->bi;
+ double spill_ef = get_block_info(get_nodes_block(br->irn))->exec_freq;
+
+ /*
+ * If the bring in node is a phi in the bring in block,
+ * we look at all definitions and sum up their execution frequencies,
+ * since spills will be placed there.
+ * (except for the case where an operand is also a phi which is spilled :-( )
+ * If that cost is higher than spilling the phi in that block, we opt for
+ * bringing the phi into the block and spill it there.
+ */
+ if (is_local_phi(bi->bl, br->irn)) {
+ ir_node *bl = bi->bl;
+ int i;
+
+ spill_ef = 0.0;
+ for (i = get_Block_n_cfgpreds(bl) - 1; i >= 0; --i)
+ spill_ef += get_block_info(get_Block_cfgpred_block(bl, i))->exec_freq;
+ }
+
+ return bi->exec_freq < spill_ef ? sched_prev(bi->first_non_in) : NULL;
+}
+
+static int get_max_pressure_so_far(const block_info_t *bi, const bring_in_t *br)
+{
+ const struct list_head *l;
+ int res = INT_MIN;
+
+ assert(br->bi == bi);
+ for (l = &br->list; l != &bi->br_head; l = l->prev) {
+ br = list_entry(l, bring_in_t, list);
+ res = MAX(res, br->sect_pressure);
+ }
+
+ /* finally consider the front pressure distance and add the reference line (the global block pressure) */
+ return MAX(res, bi->front_pressure);
+}
+
+#define block_last_bring_in(bi) list_entry((bi)->br_head.prev, bring_in_t, list)
+
+#if 0
+static int get_block_max_pressure(const block_info_t *bi)
+{
+ int max = get_max_pressure_so_far(bi, block_last_bring_in(bi));
+ return MAX(bi->pressure, max);
+}
+#endif
+
/**
- * Examine all irns which shall be in regs at the beginning of the
- * block.
+ * Try to bring a variable into a block.
+ * @param ges The state of all end sets.
+ * @param block The block.
+ * @param irn The variable.
*/
-static void fix_block_borders(global_end_state_t *ges, ir_node *block) {
- block_info_t *bi = get_block_info(block);
- belady_env_t *env = ges->env;
- void *reset_level = obstack_base(&ges->obst);
+static void optimize_variable(global_end_state_t *ges, bring_in_t *br)
+{
+ block_info_t *bi = br->bi;
+ ir_node *irn = br->irn;
+ ir_node *bl = bi->bl;
+ belady_env_t *env = ges->env;
+ void *reset_level = obstack_base(&ges->obst);
+ int k = env->n_regs;
+ int pressure_upto_use = get_max_pressure_so_far(bi, br);
+ int front_pressure = bi->front_pressure;
+ ir_node *better_spill_loc = NULL;
- ir_node *irn;
- int i;
+ assert(front_pressure <= k);
+ assert(pressure_upto_use <= k);
+
+ DBG((dbg, DBG_GLOBAL, "fixing %+F at %+F (%f), front pr: %d, pr to use: %d, first use: %x\n",
+ irn, bl, bi->exec_freq, front_pressure, pressure_upto_use, br->first_use));
- for (i = workset_get_length(bi->ws_end) - 1; i >= 0; --i)
- workset_set_version(bi->ws_end, i, ver_youngest);
+ // assert(!is_local_phi(bl, irn) || !bitset_contains_irn(ges->succ_phis, irn));
+
+ /*
+ * if we cannot bring the value to the use, let's see ifit would be worthwhile
+ * to bring the value to the beginning of the block to have a better spill
+ * location.
+ *
+ * better _spilled_here will return a node where the value can be spilled after
+ * or NULL if this block does not provide a better spill location.
+ */
+#if 1
+ if (pressure_upto_use >= k && front_pressure < k && !bitset_contains_irn(env->spilled, irn))
+ better_spill_loc = better_spilled_here(br);
+#endif
- DBG((dbg, DBG_GLOBAL, "fixing block borders at %+F (%f)\n", block, bi->exec_freq));
+ /*
+ * If either we can bring the value to the use or we should try
+ * to bring it here to do the spill here, let's try to bring it in.
+ */
+ if (better_spill_loc || pressure_upto_use < k) {
+ block_state_t *bs;
+ double bring_in_costs, local_costs;
+ rollback_info_t trans;
+ int pressure_inc;
- /* process all variables which shall be in a reg at
- * the beginning of the block in the order of the next use. */
- workset_foreach(bi->entrance_reg, irn, i) {
- double local_costs = be_get_reload_costs(env->senv, irn, bi->first_non_in);
- double bring_in_costs;
+ /* process all variables which shall be in a reg at
+ * the beginning of the block in the order of the next use. */
+ local_costs = be_get_reload_costs(env->senv, irn, br->first_use);
/* reset the lists */
ges->bs_top = NULL;
ges->ia_top = NULL;
- DBG((dbg, DBG_GLOBAL, "\ttrans in var %+F, version %x\n", irn, ges->version));
+ /* if the variable will live into this block, we must adapt the pressure.
+ * The new pressure is the MAX of:
+ * 1) the total block pressure
+ * 2) the pressure so far + the front pressure increase + 1
+ *
+ * If the second is larger than the first,
+ * we have to increment the total block pressure and hence
+ * save the old pressure to restire it in case of failing to
+ * bring the variable into the block in a register.
+ */
+ trans = trans_begin(ges);
+ bs = new_block_state(ges, bi);
+ pressure_inc = MAX(bs->pressure, better_spill_loc ? front_pressure : pressure_upto_use + 1);
+ bs->pressure = pressure_inc;
- bring_in_costs = can_bring_in(ges, block, irn, local_costs, 1);
- DBG((dbg, DBG_GLOBAL, "\tbring in: %f, local: %f", bring_in_costs, local_costs));
+ assert(bi->pressure <= k);
+ DBG((dbg, DBG_GLOBAL, "\ttrans in var %+F, version %x\n", irn, ges->version));
+ bring_in_costs = can_bring_in(ges, bl, irn, local_costs, 1);
+ DBG((dbg, DBG_GLOBAL, "\tbring in: %f, local: %f\n", bring_in_costs, local_costs));
/*
- * we were not able to let the value arrive
- * in a register at the entrance of the block
- * or it is too costly, so we have to do the reload locally
+ * Following cases can now occur:
+ * 1) There is room and costs ok
+ * 2) Cannot bring to use but can spill at begin and costs are ok
+ * 3) neither of both worked.
+ *
+ * following actions can be taken:
+ * a) commit changes
+ * b) mark phi as succeded if node was phi
+ * c) insert reload at use location
+ * d) give a spill location hint
+ *
+ * this is the case/action matrix
+ * | abcd
+ * --+----------
+ * 1 | XX
+ * 2 | XXXX
+ * 3 | X
*/
- if (bring_in_costs >= local_costs) {
- DBG((dbg, DBG_GLOBAL, " -> do local reload\n"));
- be_add_reload(env->senv, irn, bi->first_non_in, env->cls, 1);
- } else {
+
+ /* the costs were acceptable... */
+ if (bring_in_costs < local_costs) {
+ int check = 0;
+ bring_in_t *iter;
+
/*
+ * case 1 and first part of case 2:
+ * commit all the changes done. this manifests the bring-in action.
* if the transport-in was a phi (that is actually used in block)
- * it will no longer remain and we have to spill it completely.
+ * mark it in the succ_phis set to *not* phi spill it.
*/
- if (is_local_phi(block, irn))
+ materialize_and_commit_end_state(ges);
+ if (is_local_phi(bl, irn))
bitset_add_irn(ges->succ_phis, irn);
- DBG((dbg, DBG_GLOBAL, " -> bring it in\n"));
- materialize_and_commit_end_state(ges);
+ DBG((dbg, DBG_GLOBAL, "\t-> bring it in.", pressure_inc));
+
+ /* second half of case 2 */
+ if (pressure_upto_use >= k) {
+ DBG((dbg, DBG_GLOBAL, "\t-> use blocked. local reload: %+F, try spill at: %+F\n",
+ br->first_use, better_spill_loc));
+ be_add_reload(env->senv, irn, br->first_use, env->cls, 1);
+ be_add_spill(env->senv, irn, sched_next(better_spill_loc));
+ ir_nodeset_insert(env->extra_spilled, irn);
+ }
+
+ /*
+ * go from the last bring in use to the first and add all the variabled
+ * which additionally live through the block to their pressure.
+ * at the point were the actually treated use is, we have to increase
+ * the pressure by one more as the nrought in value starts to count.
+ * Finally, adjust the front pressure as well.
+ */
+ pressure_inc = 0;
+ list_for_each_entry_reverse(bring_in_t, iter, &bi->br_head, list) {
+ if (iter == br)
+ pressure_inc += pressure_upto_use < k;
+ iter->sect_pressure += pressure_inc;
+ check = MAX(check, iter->sect_pressure);
+ DBG((dbg, DBG_GLOBAL, "\tinc section pressure of %+F by %d to %d\n", iter->first_use, pressure_inc, iter->sect_pressure));
+ }
+ bi->front_pressure += pressure_inc;
+ assert(MAX(check, bi->front_pressure) <= bi->pressure);
+ DBG((dbg, DBG_GLOBAL, "\t-> result: p: %d, fp: %d\n", bi->pressure, bi->front_pressure));
}
- DBG((dbg, DBG_GLOBAL, "\n"));
+ /* case 3: nothing worked. insert normal reload and rollback. */
+ else {
+ DBG((dbg, DBG_GLOBAL, "\t-> bring in was too expensive. local reload: %+F\n", br->first_use));
+ be_add_reload(env->senv, irn, br->first_use, env->cls, 1);
+ bitset_add_irn(env->spilled, irn);
+ trans_rollback(ges, &trans);
+ }
+ }
- /* reset the obstack and create a new version. */
- obstack_free(&ges->obst, reset_level);
- ges->version = ver_make_newer(ges->version);
+ /* there was no opportunity for optimization at all. reload and be sad ... */
+ else {
+ DBG((dbg, DBG_GLOBAL, "\t-> can\'t do anything but reload before %+F\n", br->first_use));
+ be_add_reload(env->senv, irn, br->first_use, env->cls, 1);
+ bitset_add_irn(env->spilled, irn);
}
+
+ DBG((dbg, DBG_GLOBAL, "\n"));
+
+ /* reset the obstack and create a new version. */
+ obstack_free(&ges->obst, reset_level);
+ ges->version = ver_make_newer(ges->version);
}
+static bring_in_t **determine_global_order(belady_env_t *env)
+{
+ bring_in_t **res;
+ bring_in_t *elm;
+ int i, n = 0;
+
+ for (i = env->n_blocks - 1; i >= 0; --i) {
+ block_info_t *bi = get_block_info(env->blocks[i]);
+ list_for_each_entry(bring_in_t, elm, &bi->br_head, list) {
+ obstack_ptr_grow(&env->ob, elm);
+ n += 1;
+ }
+ }
+
+ obstack_ptr_grow(&env->ob, NULL);
+ res = obstack_finish(&env->ob);
+ qsort(res, n, sizeof(res[0]), bring_in_cmp);
+ return res;
+}
+
+
+
+
static void global_assign(belady_env_t *env)
{
+ ir_nodeset_iterator_t iter;
global_end_state_t ges;
- int i;
+ bring_in_t **br;
+ ir_node *irn;
+ int i, j;
/*
* sort the blocks according to execution frequency.
* That's not necessary for belady() but for the global pass later on.
*/
- qsort(env->blocks, env->n_blocks, sizeof(env->blocks[0]), block_freq_gt);
+ qsort(env->blocks, env->n_blocks, sizeof(env->blocks[0]), block_freq_dfs_gt);
memset(&ges, 0, sizeof(ges));
obstack_init(&ges.obst);
ges.bs_tops = obstack_alloc(&ges.obst, sizeof(ges.bs_tops[0]) * env->n_blocks);
ges.bs_tops_vers = obstack_alloc(&ges.obst, sizeof(ges.bs_tops_vers[0]) * env->n_blocks);
- for (i = 0; i < env->n_blocks; ++i)
+ /* invalidate all state stack pointer versions */
+ for (i = 0; i < env->n_blocks; ++i) {
+ block_info_t *bi = get_block_info(env->blocks[i]);
ges.bs_tops_vers[i] = ver_oldest;
- for (i = 0; i < env->n_blocks; ++i)
- fix_block_borders(&ges, env->blocks[i]);
+ /* Set all block end sets entries to the youngest version */
+ for (j = workset_get_length(bi->ws_end) - 1; j >= 0; --j)
+ workset_set_version(bi->ws_end, j, ver_youngest);
+ }
+
+ /* determine ordeer and optimize them */
+ for (br = determine_global_order(env); *br; ++br)
+ optimize_variable(&ges, *br);
/*
* Now we spill phis which cannot be kept since they were replaced
be_spill_phi(env->senv, irn);
}
}
+
+ /* check dominance for specially spilled nodes. */
+ foreach_ir_nodeset (env->extra_spilled, irn, iter)
+ make_spill_locations_dominate_irn(env->senv, irn);
}
static void collect_blocks(ir_node *bl, void *data)
/* init belady env */
obstack_init(&env.ob);
- env.irg = irg;
- env.arch = birg->main_env->arch_env;
- env.cls = cls;
- env.lv = be_get_birg_liveness(birg);
- env.n_regs = n_regs;
- env.ws = new_workset(&env, &env.ob);
- env.senv = be_new_spill_env(birg);
- env.ef = be_get_birg_exec_freq(birg);
- env.n_blocks = 0;
+ env.irg = irg;
+ env.arch = be_get_birg_arch_env(birg);
+ env.cls = cls;
+ env.lv = be_get_birg_liveness(birg);
+ env.dfs = env.lv->dfs;
+ env.n_regs = n_regs;
+ env.ws = new_workset(&env, &env.ob);
+ env.senv = be_new_spill_env(birg);
+ env.ef = be_get_birg_exec_freq(birg);
+ env.spilled = bitset_irg_obstack_alloc(&env.ob, irg);
+ env.extra_spilled = ir_nodeset_new(64);
+ env.n_blocks = 0;
irg_block_walk_graph(irg, NULL, collect_blocks, &env);
obstack_ptr_grow(&env.ob, NULL);
env.blocks = obstack_finish(&env.ob);
+ /* renumbering in the blocks gives nicer debug output as number are smaller. */
+#ifdef DEBUG_libfirm
+ for (i = 0; i < env.n_blocks; ++i)
+ sched_renumber(env.blocks[i]);
+#endif
+
/* Fix high register pressure in blocks with belady algorithm */
for (i = 0; i < env.n_blocks; ++i)
belady(&env, i);
global_assign(&env);
+ /* check dominance for specially spilled nodes. */
+ {
+ ir_nodeset_iterator_t iter;
+ ir_node *irn;
+
+ foreach_ir_nodeset (env.extra_spilled, irn, iter)
+ make_spill_locations_dominate_irn(env.senv, irn);
+ }
+
/* Insert spill/reload nodes into the graph and fix usages */
be_insert_spills_reloads(env.senv);
/* clean up */
be_delete_spill_env(env.senv);
+ ir_nodeset_del(env.extra_spilled);
obstack_free(&env.ob, NULL);
}
void be_init_spillbelady2(void)
{
+ lc_opt_entry_t *be_grp = lc_opt_get_grp(firm_opt_get_root(), "be");
+ lc_opt_entry_t *spill_grp = lc_opt_get_grp(be_grp, "spill");
+ lc_opt_entry_t *bel2_grp = lc_opt_get_grp(spill_grp, "belady2");
+
static be_spiller_t belady_spiller = {
be_spill_belady
};
+ lc_opt_add_table(bel2_grp, options);
be_register_spiller("belady2", &belady_spiller);
FIRM_DBG_REGISTER(dbg, "firm.be.spill.belady2");
}
projects / libfirm / blobdiff