#include "becopyopt.h"
#include "becopystat.h"
#include "bitset.h"
+#include "bearch.h"
static firm_dbg_module_t *dbg = NULL;
+#define SEARCH_FREE_COLORS
+
#define SLOTS_PINNED_GLOBAL 256
#define SLOTS_CONFLICTS 8
#define SLOTS_CHANGED_NODES 32
found->new_color = get_irn_col(qn->ou->co, irn);
}
+
/**
* Possible return values of qnode_color_irn()
*/
* 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.
- * @param irn The node to set the color for
- * @param col The color to set
+ *
+ * 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.
*
- * ASSUMPTION: Assumes that a life range of a single value can't be split into
- * several smaller intervals where other values can live in between.
- * This should be true in SSA.
*/
static ir_node *qnode_color_irn(const qnode_t *qn, ir_node *irn, int col, const ir_node *trigger) {
const be_chordal_env_t *chordal_env = qn->ou->co->chordal_env;
const arch_register_class_t *cls = chordal_env->cls;
const arch_env_t *arch_env = chordal_env->main_env->arch_env;
int irn_col = qnode_get_new_color(qn, irn);
+ ir_node *sub_res, *curr;
+ be_ifg_t *ifg = chordal_env->ifg;
+ void *iter = be_ifg_neighbours_iter_alloca(ifg);
+
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;
}
+
+#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);
+ arch_register_req_t req;
+ ir_node *curr;
+ int free_col;
+
+ /* Get all possible colors */
+ arch_put_non_ignore_regs(arch_env, cls, free_cols);
+
+ /* Exclude colors not assignable to the irn */
+ arch_get_register_req(arch_env, &req, irn, -1);
+ if (arch_register_req_is(&req, limited)) {
+ bitset_t *limited = bitset_alloca(cls->n_regs);
+ req.limited(req.limited_env, limited);
+ bitset_and(free_cols, limited);
+ }
+
+ /* 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(arch_env, irn, -1, arch_register_for_index(cls, col))) {
DBG((dbg, LEVEL_3, "\t %+F impossible\n", irn));
return CHANGE_IMPOSSIBLE;
}
/*
- * Process all nodes which would conflict with this change
+ * 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_t *ifg = chordal_env->ifg;
- void *iter = be_ifg_neighbours_iter_alloca(ifg);
- ir_node *sub_res, *curr;
-
- /*
- * 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) {
- sub_res = qnode_color_irn(qn, curr, irn_col, irn);
- if (sub_res != CHANGE_SAVE) {
- be_ifg_neighbours_break(ifg, iter);
- return sub_res;
- }
+ 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) {
+ sub_res = qnode_color_irn(qn, curr, irn_col, irn);
+ if (sub_res != CHANGE_SAVE) {
+ be_ifg_neighbours_break(ifg, iter);
+ return sub_res;
}
}
}
/*
- * If we arrive here, all sub changes have been applied.
- * So it's save to change this irn
+ * 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