Commit b80dc0bb authored by Daniel Grund's avatar Daniel Grund
Browse files

Improved start sets for blocks with one pred.

parent 9f737617
......@@ -4,8 +4,6 @@
* Copyright: (c) Universitaet Karlsruhe
* Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
*
* NOTE: Comments my be (partially) wrong, since there was a major bug
* (spilling of phis, prespill) whose fixing changed a lot.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
......@@ -50,7 +48,6 @@
static firm_dbg_module_t *dbg = NULL;
#define MIN(a,b) (((a)<(b))?(a):(b))
#undef SINGLE_START_PROJS
typedef struct _workset_t workset_t;
......@@ -77,10 +74,6 @@ struct _workset_t {
loc_t vals[1]; /**< inlined array of the values/distances in this working set */
};
typedef struct _block_info_t {
workset_t *ws_start, *ws_end;
} block_info_t;
/**
* Alloc a new workset on obstack @p ob with maximum size @p max
*/
......@@ -219,13 +212,28 @@ static INLINE int workset_contains(const workset_t *ws, const ir_node *val) {
#define workset_get_val(ws, i) ((ws)->vals[i].irn)
#define workset_sort(ws) qsort((ws)->vals, (ws)->len, sizeof((ws)->vals[0]), loc_compare);
typedef struct _block_info_t {
workset_t *ws_start, *ws_end;
} block_info_t;
static INLINE void *new_block_info(struct obstack *ob) {
block_info_t *res = obstack_alloc(ob, sizeof(*res));
res->ws_start = NULL;
res->ws_end = NULL;
return res;
}
#define get_block_info(blk) ((block_info_t *)get_irn_link(blk))
#define set_block_info(blk, info) set_irn_link(blk, info)
static int is_mem_phi(const ir_node *irn, void *data) {
workset_t *sws;
ir_node *blk = get_nodes_block(irn);
DBG((dbg, DBG_SPILL, "Is %+F a mem-phi?\n", irn));
sws = ((block_info_t *) get_irn_link(blk))->ws_start;
sws = get_block_info(blk)->ws_start;
DBG((dbg, DBG_SPILL, " %d\n", !workset_contains(sws, irn)));
return !workset_contains(sws, irn);
}
......@@ -238,84 +246,6 @@ static int is_mem_phi(const ir_node *irn, void *data) {
((arch_irn_is_ignore(bel->arch, def) ) ? 0 : be_get_next_use(bel->uses, from, from_step, def, skip_from_uses))
/**
* Collects all values live-in at block @p blk and all phi results in this block.
* Then it adds the best values (at most n_regs) to the blocks start_workset.
* The phis among the remaining values get spilled: Introduce psudo-copies of
* their args to break interference and make it possible to spill them to the
* same spill slot.
*/
static void compute_block_start_info(ir_node *blk, void *env) {
belady_env_t *bel = env;
block_info_t *blk_info;
ir_node *irn, *first;
irn_live_t *li;
int i, count, ws_count;
loc_t loc, *starters;
ir_graph *irg = get_irn_irg(blk);
struct obstack ob;
obstack_init(&ob);
/* Get all values living at the block start */
DBG((dbg, DBG_START, "Living at start of %+F:\n", blk));
first = sched_first(blk);
count = 0;
sched_foreach(blk, irn)
if (is_Phi(irn) && arch_get_irn_reg_class(bel->arch, irn, -1) == bel->cls) {
loc.irn = irn;
loc.time = get_distance(bel, first, 0, irn, 0);
obstack_grow(&ob, &loc, sizeof(loc));
DBG((dbg, DBG_START, " %+F:\n", irn));
count++;
} else
break;
live_foreach(blk, li)
if (live_is_in(li) && arch_get_irn_reg_class(bel->arch, li->irn, -1) == bel->cls) {
loc.irn = (ir_node *)li->irn;
loc.time = get_distance(bel, first, 0, li->irn, 0);
obstack_grow(&ob, &loc, sizeof(loc));
DBG((dbg, DBG_START, " %+F:\n", irn));
count++;
}
starters = obstack_finish(&ob);
/* Sort all values */
qsort(starters, count, sizeof(starters[0]), loc_compare);
/* Create the start workset for this block. Copy the best ones from starters */
blk_info = obstack_alloc(&bel->ob, sizeof(*blk_info));
set_irn_link(blk, blk_info);
ws_count = MIN(count, bel->n_regs);
blk_info->ws_start = new_workset(&bel->ob, bel);
workset_bulk_fill(blk_info->ws_start, ws_count, starters);
/* Spill the phis among the remaining values */
for (i=ws_count; i<count; ++i) {
int o, max;
irn = starters[i].irn;
if (!is_Phi(irn) || get_nodes_block(irn) != blk)
continue;
DBG((dbg, DBG_START, "For %+F:\n", irn));
for (max=get_irn_arity(irn), o=0; o<max; ++o) {
ir_node *arg = get_irn_n(irn, o);
ir_node *pred_block = get_Block_cfgpred_block(get_nodes_block(irn), o);
ir_node *cpy = be_new_Copy(bel->cls, irg, pred_block, arg);
pset_insert_ptr(bel->copies, cpy);
DBG((dbg, DBG_START, " place a %+F of %+F in %+F\n", cpy, arg, pred_block));
sched_add_before(pred_block, cpy);
set_irn_n(irn, o, cpy);
}
}
obstack_free(&ob, NULL);
}
/**
* Performs the actions neccessary to grant the request that:
* - new_vals can be held in registers
......@@ -372,7 +302,7 @@ static void displace(belady_env_t *bel, workset_t *new_vals, int is_usage) {
ir_node *irn = ws->vals[i].irn;
if (!pset_find_ptr(bel->used, irn)) {
ir_node *curr_bb = get_nodes_block(bel->instr);
workset_t *ws_start = ((block_info_t *) get_irn_link(curr_bb))->ws_start;
workset_t *ws_start = get_block_info(curr_bb)->ws_start;
workset_remove(ws_start, irn);
DBG((dbg, DBG_DECIDE, " dispose %+F dumb\n", irn));
......@@ -390,6 +320,118 @@ static void displace(belady_env_t *bel, workset_t *new_vals, int is_usage) {
workset_bulk_insert(bel->ws, demand, to_insert);
}
static void belady(ir_node *blk, void *env);
/**
* Collects all values live-in at block @p blk and all phi results in this block.
* Then it adds the best values (at most n_regs) to the blocks start_workset.
* The phis among the remaining values get spilled: Introduce psudo-copies of
* their args to break interference and make it possible to spill them to the
* same spill slot.
*/
static block_info_t *compute_block_start_info(ir_node *blk, void *env) {
belady_env_t *bel = env;
ir_node *irn, *first;
irn_live_t *li;
int i, count, ws_count;
loc_t loc, *starters;
ir_graph *irg = get_irn_irg(blk);
struct obstack ob;
block_info_t *res = get_block_info(blk);
/* Have we seen this block before? */
if (res)
return res;
/* Create the block info for this block. */
res = new_block_info(&bel->ob);
set_block_info(blk, res);
/* Get all values living at the block start sorted by next use*/
obstack_init(&ob);
DBG((dbg, DBG_START, "Living at start of %+F:\n", blk));
first = sched_first(blk);
count = 0;
sched_foreach(blk, irn)
if (is_Phi(irn) && arch_get_irn_reg_class(bel->arch, irn, -1) == bel->cls) {
loc.irn = irn;
loc.time = get_distance(bel, first, 0, irn, 0);
obstack_grow(&ob, &loc, sizeof(loc));
DBG((dbg, DBG_START, " %+F:\n", irn));
count++;
} else
break;
live_foreach(blk, li)
if (live_is_in(li) && arch_get_irn_reg_class(bel->arch, li->irn, -1) == bel->cls) {
loc.irn = (ir_node *)li->irn;
loc.time = get_distance(bel, first, 0, li->irn, 0);
obstack_grow(&ob, &loc, sizeof(loc));
DBG((dbg, DBG_START, " %+F:\n", irn));
count++;
}
starters = obstack_finish(&ob);
qsort(starters, count, sizeof(starters[0]), loc_compare);
/* If we have only one predecessor, we want the start_set of blk to be the end_set of pred */
if (get_irn_arity(blk) == 1 && blk != get_irg_start_block(get_irn_irg(blk))) {
ir_node *pred_blk = get_Block_cfgpred_block(blk, 0);
block_info_t *pred_info = get_block_info(pred_blk);
/* if pred block has not been processed yet, do it now */
if (! pred_info) {
belady(pred_blk, bel);
pred_info = get_block_info(pred_blk);
}
/* now we have an end_set of pred */
assert(pred_info->ws_end && "The recursive call (above) is supposed to compute an end_set");
res->ws_start = workset_clone(&bel->ob, pred_info->ws_end);
} else
/* Else we want the start_set to be the values used 'the closest' */
{
/* Copy the best ones from starters to start workset */
ws_count = MIN(count, bel->n_regs);
res->ws_start = new_workset(&bel->ob, bel);
workset_bulk_fill(res->ws_start, ws_count, starters);
}
/* The phis of this block which are not in the start set have to be spilled later.
* Therefore we add temporary copies in the pred_blocks so the spills can spill
* into the same spill slot.
* After spilling these copies get deleted. */
for (i=workset_get_length(res->ws_start); i<count; ++i) {
int o, max;
irn = starters[i].irn;
if (!is_Phi(irn) || get_nodes_block(irn) != blk)
continue;
DBG((dbg, DBG_START, "For %+F:\n", irn));
for (max=get_irn_arity(irn), o=0; o<max; ++o) {
ir_node *arg = get_irn_n(irn, o);
ir_node *pred_block = get_Block_cfgpred_block(get_nodes_block(irn), o);
ir_node *cpy = be_new_Copy(bel->cls, irg, pred_block, arg);
pset_insert_ptr(bel->copies, cpy);
DBG((dbg, DBG_START, " place a %+F of %+F in %+F\n", cpy, arg, pred_block));
sched_add_before(pred_block, cpy);
set_irn_n(irn, o, cpy);
}
}
obstack_free(&ob, NULL);
return res;
}
/**
* For the given block @p blk, decide for each values
* whether it is used from a register or is reloaded
......@@ -400,17 +442,20 @@ static void belady(ir_node *blk, void *env) {
workset_t *new_vals;
ir_node *irn;
int iter;
block_info_t *blk_info;
#ifdef SINGLE_START_PROJS
ir_node *start_blk = get_irg_start_block(get_irn_irg(blk));
#endif
block_info_t *blk_info = get_irn_link(blk);
/* Don't do a block twice */
if (get_block_info(blk))
return;
/* get the starting workset for this block */
blk_info = compute_block_start_info(blk, bel);
DBG((dbg, DBG_DECIDE, "\n"));
DBG((dbg, DBG_DECIDE, "Decide for %+F\n", blk));
workset_copy(bel->ws, blk_info->ws_start);
DBG((dbg, DBG_WSETS, "Initial start workset for %+F:\n", blk));
DBG((dbg, DBG_WSETS, "Start workset for %+F:\n", blk));
workset_foreach(bel->ws, irn, iter)
DBG((dbg, DBG_WSETS, " %+F\n", irn));
......@@ -423,14 +468,6 @@ static void belady(ir_node *blk, void *env) {
assert(workset_get_length(bel->ws) <= bel->n_regs && "Too much values in workset!");
#ifdef SINGLE_START_PROJS
if (is_Phi(irn) ||
(is_Proj(irn) && blk!=start_blk) ||
(get_irn_mode(irn) == mode_T && blk==start_blk)) {
DBG((dbg, DBG_DECIDE, " ...%+F skipped\n", irn));
continue;
}
#else
/* projs are handled with the tuple value.
* Phis are no real instr (see insert_starters)
* instr_nr does not increase */
......@@ -438,7 +475,6 @@ static void belady(ir_node *blk, void *env) {
DBG((dbg, DBG_DECIDE, " ...%+F skipped\n", irn));
continue;
}
#endif
DBG((dbg, DBG_DECIDE, " ...%+F\n", irn));
/* set instruction in the workset */
......@@ -466,9 +502,6 @@ static void belady(ir_node *blk, void *env) {
/* Remember end-workset for this block */
blk_info->ws_end = workset_clone(&bel->ob, bel->ws);
DBG((dbg, DBG_WSETS, "Start workset for %+F:\n", blk));
workset_foreach(blk_info->ws_start, irn, iter)
DBG((dbg, DBG_WSETS, " %+F\n", irn));
DBG((dbg, DBG_WSETS, "End workset for %+F:\n", blk));
workset_foreach(blk_info->ws_end, irn, iter)
DBG((dbg, DBG_WSETS, " %+F\n", irn));
......@@ -487,12 +520,12 @@ static void fix_block_borders(ir_node *blk, void *env) {
DBG((dbg, DBG_FIX, "\n"));
DBG((dbg, DBG_FIX, "Fixing %+F\n", blk));
wsb = ((block_info_t *)get_irn_link(blk))->ws_start;
wsb = get_block_info(blk)->ws_start;
/* process all pred blocks */
for (i=0, max=get_irn_arity(blk); i<max; ++i) {
ir_node *irnb, *irnp, *pred = get_Block_cfgpred_block(blk, i);
workset_t *wsp = ((block_info_t *)get_irn_link(pred))->ws_end;
workset_t *wsp = get_block_info(pred)->ws_end;
DBG((dbg, DBG_FIX, " Pred %+F\n", pred));
......@@ -597,15 +630,13 @@ void be_spill_belady(const be_chordal_env_t *chordal_env) {
DBG((dbg, LEVEL_1, "running on register class: %s\n", bel.cls->name));
/* do the work */
irg_block_walk_graph(chordal_env->irg, compute_block_start_info, NULL, &bel);
irg_block_walk_graph(chordal_env->irg, belady, NULL, &bel);
be_clear_links(chordal_env->irg);
irg_block_walk_graph(chordal_env->irg, NULL, belady, &bel);
irg_block_walk_graph(chordal_env->irg, fix_block_borders, NULL, &bel);
be_insert_spills_reloads(bel.senv, bel.reloads);
remove_unused_reloads(chordal_env->irg, &bel);
remove_copies(&bel);
/* clean up */
del_pset(bel.reloads);
be_delete_spill_env(bel.senv);
......
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