Commit f7fe0b3b authored by Matthias Braun's avatar Matthias Braun
Browse files

remove copyheur + copyheur2

parent 763096fc
/*
* This file is part of libFirm.
* Copyright (C) 2012 University of Karlsruhe.
*/
/**
* @file
* @brief First simple copy minimization heuristics.
* @author Daniel Grund
* @date 12.04.2005
*
* Heuristic for minimizing copies using a queue which holds 'qnodes' not yet
* examined. A qnode has a 'target color', nodes out of the opt unit and
* a 'conflict graph'. 'Conflict graph' = "Interference graph' + 'conflict edges'
* A 'max indep set' is determined from these. We try to color this mis using a
* color-exchanging mechanism. Occuring conflicts are modeled with 'conflict edges'
* and the qnode is reinserted in the queue. The first qnode colored without
* conflicts is the best one.
*/
#include "debug.h"
#include "bitset.h"
#include "raw_bitset.h"
#include "xmalloc.h"
#include "becopyopt_t.h"
#include "becopystat.h"
#include "belive.h"
#include "beirg.h"
#include "bemodule.h"
DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
/** Defines an invalid register index. */
#define NO_COLOR (-1)
#define SEARCH_FREE_COLORS
#define SLOTS_PINNED_GLOBAL 64
#define SLOTS_CONFLICTS 8
#define SLOTS_CHANGED_NODES 32
#define list_entry_queue(lh) list_entry(lh, qnode_t, queue)
#define HASH_CONFLICT(c) (hash_irn(c.n1) ^ hash_irn(c.n2))
/**
* Modeling additional conflicts between nodes. NOT live range interference
*/
typedef struct conflict_t {
const ir_node *n1, *n2;
} conflict_t;
/**
* If an irn is changed, the changes first get stored in a node_stat_t,
* to allow undo of changes (=drop new data) in case of conflicts.
*/
typedef struct node_stat_t {
ir_node *irn;
int new_color;
unsigned pinned_local :1;
} node_stat_t;
/**
* Represents a node in the optimization queue.
*/
typedef struct qnode_t {
struct list_head queue; /**< chaining of unit_t->queue */
int color; /**< target color */
set *conflicts; /**< contains conflict_t's. All internal conflicts */
int mis_costs; /**< costs of nodes/copies in the mis. */
int mis_size; /**< size of the array below */
ir_node **mis; /**< the nodes of unit_t->nodes[] being part of the max independent set */
set *changed_nodes; /**< contains node_stat_t's. */
} qnode_t;
static pset *pinned_global; /**< optimized nodes should not be altered any more */
static int set_cmp_conflict_t(const void *x, const void *y, size_t size)
{
const conflict_t *xx = (const conflict_t*)x;
const conflict_t *yy = (const conflict_t*)y;
(void) size;
return xx->n1 != yy->n1 || xx->n2 != yy->n2;
}
/**
* If a local pinned conflict occurs, a new edge in the conflict graph is added.
* The next maximum independent set build, will regard it.
*/
static inline void qnode_add_conflict(const qnode_t *qn, const ir_node *n1, const ir_node *n2)
{
conflict_t c;
DBG((dbg, LEVEL_4, "\t %+F -- %+F\n", n1, n2));
if (get_irn_idx(n1) < get_irn_idx(n2)) {
c.n1 = n1;
c.n2 = n2;
} else {
c.n1 = n2;
c.n2 = n1;
}
(void)set_insert(conflict_t, qn->conflicts, &c, sizeof(c), HASH_CONFLICT(c));
}
/**
* Checks if two nodes are in a conflict.
*/
static inline int qnode_are_conflicting(const qnode_t *qn, const ir_node *n1, const ir_node *n2)
{
conflict_t c;
/* search for live range interference */
if (n1 != n2) {
if (be_values_interfere(n1, n2))
return 1;
}
/* search for recoloring conflicts */
if (get_irn_idx(n1) < get_irn_idx(n2)) {
c.n1 = n1;
c.n2 = n2;
} else {
c.n1 = n2;
c.n2 = n1;
}
return set_find(conflict_t, qn->conflicts, &c, sizeof(c), HASH_CONFLICT(c)) != 0;
}
static int set_cmp_node_stat_t(const void *x, const void *y, size_t size)
{
(void) size;
return ((const node_stat_t*)x)->irn != ((const node_stat_t*)y)->irn;
}
/**
* Finds a node status entry of a node if existent. Otherwise return NULL
*/
static inline const node_stat_t *qnode_find_node(const qnode_t *qn, ir_node *irn)
{
node_stat_t find;
find.irn = irn;
return set_find(node_stat_t, qn->changed_nodes, &find, sizeof(find), hash_irn(irn));
}
/**
* Finds a node status entry of a node if existent. Otherwise it will return
* an initialized new entry for this node.
*/
static inline node_stat_t *qnode_find_or_insert_node(const qnode_t *qn, ir_node *irn)
{
node_stat_t find;
find.irn = irn;
find.new_color = NO_COLOR;
find.pinned_local = 0;
return set_insert(node_stat_t, qn->changed_nodes, &find, sizeof(find), hash_irn(irn));
}
/**
* Returns the virtual color of a node if set before, else returns the real color.
*/
static inline int qnode_get_new_color(const qnode_t *qn, ir_node *irn)
{
const node_stat_t *found = qnode_find_node(qn, irn);
if (found)
return found->new_color;
else
return get_irn_col(irn);
}
/**
* Sets the virtual color of a node.
*/
static inline void qnode_set_new_color(const qnode_t *qn, ir_node *irn, int color)
{
node_stat_t *found = qnode_find_or_insert_node(qn, irn);
found->new_color = color;
DBG((dbg, LEVEL_3, "\t col(%+F) := %d\n", irn, color));
}
/**
* Checks if a node is local pinned. A node is local pinned, iff it belongs
* to the same optimization unit and has been optimized before the current
* processed node.
*/
static inline int qnode_is_pinned_local(const qnode_t *qn, ir_node *irn)
{
const node_stat_t *found = qnode_find_node(qn, irn);
if (found)
return found->pinned_local;
else
return 0;
}
/**
* Local-pins a node, so optimizations of further nodes of the same opt unit
* can handle situations in which a color change would undo prior optimizations.
*/
static inline void qnode_pin_local(const qnode_t *qn, ir_node *irn)
{
node_stat_t *found = qnode_find_or_insert_node(qn, irn);
found->pinned_local = 1;
if (found->new_color == NO_COLOR)
found->new_color = get_irn_col(irn);
}
/**
* Possible return values of qnode_color_irn()
*/
#define CHANGE_SAVE NULL
#define CHANGE_IMPOSSIBLE (ir_node *)1
/**
* Performs virtual re-coloring of node @p n to color @p col. Virtual colors of
* other nodes are changed too, as required to preserve correctness. Function is
* aware of local and global pinning. Recursive.
*
* If irn == trigger the color @p col must be used. (the first recoloring)
* If irn != trigger an arbitrary free color may be used. If no color is free, @p col is used.
*
* @param irn The node to set the color for
* @param col The color to set
* @param trigger The irn that caused the wish to change the color of the irn
* External callers must call with trigger = irn
*
* @return CHANGE_SAVE iff setting the color is possible, with all transitive effects.
* CHANGE_IMPOSSIBLE iff conflicts with reg-constraintsis occured.
* Else the first conflicting ir_node encountered is returned.
*
*/
static ir_node *qnode_color_irn(qnode_t const *const qn, ir_node *const irn, int const col, ir_node const *const trigger, bitset_t const *const allocatable_regs, be_ifg_t *const ifg)
{
int irn_col = qnode_get_new_color(qn, irn);
neighbours_iter_t iter;
DBG((dbg, LEVEL_3, "\t %+F \tcaused col(%+F) \t%2d --> %2d\n", trigger, irn, irn_col, col));
/* If the target color is already set do nothing */
if (irn_col == col) {
DBG((dbg, LEVEL_3, "\t %+F same color\n", irn));
return CHANGE_SAVE;
}
/* If the irn is pinned, changing color is impossible */
if (pset_find_ptr(pinned_global, irn) || qnode_is_pinned_local(qn, irn)) {
DBG((dbg, LEVEL_3, "\t %+F conflicting\n", irn));
return irn;
}
arch_register_req_t const *const req = arch_get_irn_register_req(irn);
arch_register_class_t const *const cls = req->cls;
#ifdef SEARCH_FREE_COLORS
/* If we resolve conflicts (recursive calls) we can use any unused color.
* In case of the first call @p col must be used.
*/
if (irn != trigger) {
bitset_t *free_cols = bitset_alloca(cls->n_regs);
int free_col;
/* Get all possible colors */
bitset_copy(free_cols, allocatable_regs);
/* Exclude colors not assignable to the irn */
if (arch_register_req_is(req, limited))
rbitset_and(free_cols->data, req->limited, free_cols->size);
/* Exclude the color of the irn, because it must _change_ its color */
bitset_clear(free_cols, irn_col);
/* Exclude all colors used by adjacent nodes */
be_ifg_foreach_neighbour(ifg, &iter, irn, curr)
bitset_clear(free_cols, qnode_get_new_color(qn, curr));
free_col = bitset_next_set(free_cols, 0);
if (free_col != -1) {
qnode_set_new_color(qn, irn, free_col);
return CHANGE_SAVE;
}
}
#endif /* SEARCH_FREE_COLORS */
/* If target color is not allocatable changing color is impossible */
if (!arch_reg_is_allocatable(req, arch_register_for_index(cls, col))) {
DBG((dbg, LEVEL_3, "\t %+F impossible\n", irn));
return CHANGE_IMPOSSIBLE;
}
/*
* If we arrive here changing color may be possible, but there may be conflicts.
* Try to color all conflicting nodes 'curr' with the color of the irn itself.
*/
be_ifg_foreach_neighbour(ifg, &iter, irn, curr) {
DBG((dbg, LEVEL_3, "\t Confl %+F(%d)\n", curr, qnode_get_new_color(qn, curr)));
if (qnode_get_new_color(qn, curr) == col && curr != trigger) {
ir_node *const sub_res = qnode_color_irn(qn, curr, irn_col, irn, allocatable_regs, ifg);
if (sub_res != CHANGE_SAVE) {
be_ifg_neighbours_break(&iter);
return sub_res;
}
}
}
/*
* If we arrive here, all conflicts were resolved.
* So it is save to change this irn
*/
qnode_set_new_color(qn, irn, col);
return CHANGE_SAVE;
}
/**
* Tries to set the colors for all members of this queue node;
* to the target color qn->color
* @returns 1 iff all members colors could be set
* 0 else
*/
static int qnode_try_color(qnode_t const *const qn, bitset_t const *const allocatable_regs, be_ifg_t *const ifg)
{
int i;
for (i=0; i<qn->mis_size; ++i) {
ir_node *test_node, *confl_node;
test_node = qn->mis[i];
DBG((dbg, LEVEL_3, "\t Testing %+F\n", test_node));
confl_node = qnode_color_irn(qn, test_node, qn->color, test_node, allocatable_regs, ifg);
if (confl_node == CHANGE_SAVE) {
DBG((dbg, LEVEL_3, "\t Save --> pin local\n"));
qnode_pin_local(qn, test_node);
} else if (confl_node == CHANGE_IMPOSSIBLE) {
DBG((dbg, LEVEL_3, "\t Impossible --> remove from qnode\n"));
qnode_add_conflict(qn, test_node, test_node);
return 0;
} else {
if (qnode_is_pinned_local(qn, confl_node)) {
/* changing test_node would change back a node of current ou */
if (confl_node == qn->mis[0]) {
/* Adding a conflict edge between testnode and conflnode
* would introduce a root -- arg interference.
* So remove the arg of the qn */
DBG((dbg, LEVEL_3, "\t Conflicting local with phi --> remove from qnode\n"));
qnode_add_conflict(qn, test_node, test_node);
} else {
DBG((dbg, LEVEL_3, "\t Conflicting local --> add conflict\n"));
qnode_add_conflict(qn, confl_node, test_node);
}
}
if (pset_find_ptr(pinned_global, confl_node)) {
/* changing test_node would change back a node of a prior ou */
DBG((dbg, LEVEL_3, "\t Conflicting global --> remove from qnode\n"));
qnode_add_conflict(qn, test_node, test_node);
}
return 0;
}
}
return 1;
}
/**
* Determines a maximum weighted independent set with respect to
* the interference and conflict edges of all nodes in a qnode.
*/
static inline void qnode_max_ind_set(qnode_t *qn, const unit_t *ou)
{
ir_node **safe, **unsafe;
int i, o, safe_count, safe_costs, unsafe_count, *unsafe_costs;
bitset_t *curr, *best;
int next, curr_weight, best_weight = 0;
/* assign the nodes into two groups.
* safe: node has no interference, hence it is in every max stable set.
* unsafe: node has an interference
*/
safe = ALLOCAN(ir_node*, ou->node_count - 1);
safe_costs = 0;
safe_count = 0;
unsafe = ALLOCAN(ir_node*, ou->node_count - 1);
unsafe_costs = ALLOCAN(int, ou->node_count - 1);
unsafe_count = 0;
for (i=1; i<ou->node_count; ++i) {
int is_safe = 1;
for (o=1; o<ou->node_count; ++o) {
if (qnode_are_conflicting(qn, ou->nodes[i], ou->nodes[o])) {
if (i!=o) {
unsafe_costs[unsafe_count] = ou->costs[i];
unsafe[unsafe_count] = ou->nodes[i];
++unsafe_count;
}
is_safe = 0;
break;
}
}
if (is_safe) {
safe_costs += ou->costs[i];
safe[safe_count++] = ou->nodes[i];
}
}
/* now compute the best set out of the unsafe nodes*/
best = bitset_alloca(unsafe_count);
if (unsafe_count > MIS_HEUR_TRIGGER) {
/* Heuristic: Greedy trial and error form index 0 to unsafe_count-1 */
for (i=0; i<unsafe_count; ++i) {
bitset_set(best, i);
/* check if it is a stable set */
for (o=bitset_next_set(best, 0); o!=-1 && o<=i; o=bitset_next_set(best, o+1))
if (qnode_are_conflicting(qn, unsafe[i], unsafe[o])) {
bitset_clear(best, i); /* clear the bit and try next one */
break;
}
}
/* compute the weight */
bitset_foreach(best, pos)
best_weight += unsafe_costs[pos];
} else {
/* Exact Algorithm: Brute force */
curr = bitset_alloca(unsafe_count);
bitset_set_all(curr);
while (!bitset_is_empty(curr)) {
/* check if curr is a stable set */
for (i=bitset_next_set(curr, 0); i!=-1; i=bitset_next_set(curr, i+1))
for (o=bitset_next_set(curr, i); o!=-1; o=bitset_next_set(curr, o+1)) /* !!!!! difference to ou_max_ind_set_costs(): NOT (curr, i+1) */
if (qnode_are_conflicting(qn, unsafe[i], unsafe[o]))
goto no_stable_set;
/* if we arrive here, we have a stable set */
/* compute the weight of the stable set*/
curr_weight = 0;
bitset_foreach(curr, pos)
curr_weight += unsafe_costs[pos];
/* any better ? */
if (curr_weight > best_weight) {
best_weight = curr_weight;
bitset_copy(best, curr);
}
no_stable_set:
bitset_minus1(curr);
}
}
/* transfer the best set into the qn */
qn->mis_size = 1+safe_count+bitset_popcount(best);
qn->mis_costs = safe_costs+best_weight;
qn->mis[0] = ou->nodes[0]; /* the root is always in a max stable set */
next = 1;
for (i=0; i<safe_count; ++i)
qn->mis[next++] = safe[i];
bitset_foreach(best, pos)
qn->mis[next++] = unsafe[pos];
}
/**
* Creates a new qnode
*/
static inline qnode_t *new_qnode(const unit_t *ou, int color)
{
qnode_t *qn = XMALLOC(qnode_t);
qn->color = color;
qn->mis = XMALLOCN(ir_node*, ou->node_count);
qn->conflicts = new_set(set_cmp_conflict_t, SLOTS_CONFLICTS);
qn->changed_nodes = new_set(set_cmp_node_stat_t, SLOTS_CHANGED_NODES);
return qn;
}
/**
* Frees space used by a queue node
*/
static inline void free_qnode(qnode_t *qn)
{
del_set(qn->conflicts);
del_set(qn->changed_nodes);
free(qn->mis);
free(qn);
}
/**
* Inserts a qnode in the sorted queue of the optimization unit. Queue is
* ordered by field 'size' (the size of the mis) in decreasing order.
*/
static inline void ou_insert_qnode(unit_t *ou, qnode_t *qn)
{
struct list_head *lh;
if (qnode_are_conflicting(qn, ou->nodes[0], ou->nodes[0])) {
/* root node is not in qnode */
free_qnode(qn);
return;
}
qnode_max_ind_set(qn, ou);
/* do the insertion */
DBG((dbg, LEVEL_4, "\t Insert qnode color %d with cost %d\n", qn->color, qn->mis_costs));
lh = &ou->queue;
while (lh->next != &ou->queue) {
qnode_t *curr = list_entry_queue(lh->next);
if (curr->mis_costs <= qn->mis_costs)
break;
lh = lh->next;
}
list_add(&qn->queue, lh);
}
/**
* Tries to re-allocate colors of nodes in this opt unit, to achieve lower
* costs of copy instructions placed during SSA-destruction and lowering.
* Works only for opt units with exactly 1 root node, which is the
* case for approximately 80% of all phi classes and 100% of register constrained
* nodes. (All other phi classes are reduced to this case.)
*/
static void ou_optimize(unit_t *ou, bitset_t const *const allocatable_regs, be_ifg_t *const ifg)
{
DBG((dbg, LEVEL_1, "\tOptimizing unit:\n"));
for (int i = 0; i < ou->node_count; ++i)
DBG((dbg, LEVEL_1, "\t %+F\n", ou->nodes[i]));
/* init queue */
INIT_LIST_HEAD(&ou->queue);
arch_register_req_t const *const req = arch_get_irn_register_req(ou->nodes[0]);
unsigned const n_regs = req->cls->n_regs;
if (arch_register_req_is(req, limited)) {
unsigned const* limited = req->limited;
for (unsigned idx = 0; idx != n_regs; ++idx) {
if (!bitset_is_set(allocatable_regs, idx))
continue;
if (!rbitset_is_set(limited, idx))
continue;
ou_insert_qnode(ou, new_qnode(ou, idx));
}
} else {
for (unsigned idx = 0; idx != n_regs; ++idx) {
if (!bitset_is_set(allocatable_regs, idx))
continue;
ou_insert_qnode(ou, new_qnode(ou, idx));
}
}
/* search best */
qnode_t *curr;
for (;;) {
assert(!list_empty(&ou->queue));
/* get head of queue */
curr = list_entry_queue(ou->queue.next);
list_del(&curr->queue);
DBG((dbg, LEVEL_2, "\t Examine qnode color %d with cost %d\n", curr->color, curr->mis_costs));
/* try */
if (qnode_try_color(curr, allocatable_regs, ifg))
break;
/* no success, so re-insert */
del_set(curr->changed_nodes);
curr->changed_nodes = new_set(set_cmp_node_stat_t, SLOTS_CHANGED_NODES);
ou_insert_qnode(ou, curr);
}
/* apply the best found qnode */
if (curr->mis_size >= 2) {
int root_col = qnode_get_new_color(curr, ou->nodes[0]);
DBG((dbg, LEVEL_1, "\t Best color: %d Costs: %d << %d << %d\n", curr->color, ou->min_nodes_costs, ou->all_nodes_costs - curr->mis_costs, ou->all_nodes_costs));
/* globally pin root and all args which have the same color */
pset_insert_ptr(pinned_global, ou->nodes[0]);
for (int i = 1; i < ou->node_count; ++i) {
ir_node *irn = ou->nodes[i];
int nc = qnode_get_new_color(curr, irn);
if (nc != NO_COLOR && nc == root_col)
pset_insert_ptr(pinned_global, irn);
}
/* set color of all changed nodes */
foreach_set(curr->changed_nodes, node_stat_t, ns) {
/* NO_COLOR is possible, if we had an undo */
if (ns->new_color != NO_COLOR) {
DBG((dbg, LEVEL_1, "\t color(%+F) := %d\n", ns->irn, ns->new_color));
set_irn_col(req->cls, ns->irn, ns->new_color);
}
}
}
/* free best qnode (curr) and queue */
free_qnode(curr);
list_for_each_entry_safe(qnode_t, curr, tmp, &ou->queue, queue)
free_qnode(curr);
}
/**
* Solves the problem using a heuristic approach
* Uses the OU data structure
*/
int co_solve_heuristic(copy_opt_t *co)
{
ASSERT_OU_AVAIL(co);
pinned_global = pset_new_ptr(SLOTS_PINNED_GLOBAL);
bitset_t const *const allocatable_regs = co->cenv->allocatable_regs;
be_ifg_t *const ifg = co->cenv->ifg;
list_for_each_entry(unit_t, curr, &co->units, units) {
if (curr->node_count > 1)
ou_optimize(curr, allocatable_regs, ifg);
}
del_pset(pinned_global);
return 0;
}
BE_REGISTER_MODULE_CONSTRUCTOR(be_init_copyheur)
void be_init_copyheur(void)
{
static co_algo_info copyheur = {
co_solve_heuristic, 0
};