[libfirm] / ir / be / belower.c

/**
 * Author:      Christian Wuerdig
 * Date:        2005/12/14
 * Copyright:   (c) Universitaet Karlsruhe
 * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
 * CVS-Id:      $Id$
 *
 * Performs lowering of perm nodes and spill/reload optimization.
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdlib.h>

#include "ircons.h"
#include "ident.h"
#include "debug.h"
#include "irhooks.h"

#include "bearch.h"
#include "belower.h"
#include "benode_t.h"
#include "bechordal_t.h"
#include "besched_t.h"

#include "irgmod.h"
#include "iredges_t.h"
#include "irgwalk.h"

#ifdef HAVE_MALLOC_H
 #include <malloc.h>
#endif
#ifdef HAVE_ALLOCA_H
 #include <alloca.h>
#endif

#undef is_Perm
#define is_Perm(arch_env, irn) (arch_irn_classify(arch_env, irn) == arch_irn_class_perm)

/* collect static data about perms */
typedef struct _perm_stat_t {
        const arch_register_class_t *cls; /**< the current register class */
    int  *perm_size_ar;       /**< the sizes of all perms in an irg */
    int  *real_perm_size_ar;  /**< the sizes of all perms in an irg */
        int  *chain_len_ar;       /**< the sizes of all chains for all perms */
        int  *cycle_len_ar;       /**< the siyes of all cycles for all perms */
        int   num_perms;          /**< number of all perms */
        int   num_real_perms;     /**< number of all perms */
        int   num_chains;         /**< the number of all chains */
        int   num_cycles;         /**< the number of all cycles */
} perm_stat_t;

/* lowering walker environment */
typedef struct _lower_env_t {
        be_chordal_env_t  *chord_env;
        unsigned           do_copy:1;
        unsigned           do_stat:1;
        unsigned           pstat_n:30;
        perm_stat_t      **pstat;
        DEBUG_ONLY(firm_dbg_module_t *dbg_module;)
} lower_env_t;

/* holds a perm register pair */
typedef struct _reg_pair_t {
        const arch_register_t *in_reg;    /**< a perm IN register */
        ir_node               *in_node;   /**< the in node to which the register belongs */

        const arch_register_t *out_reg;   /**< a perm OUT register */
        ir_node               *out_node;  /**< the out node to which the register belongs */

        int                    checked;   /**< indicates whether the pair was check for cycle or not */
} reg_pair_t;

typedef enum _perm_type_t {
        PERM_CYCLE,
        PERM_CHAIN,
        PERM_SWAP,
        PERM_COPY
} perm_type_t;

/* structure to represent cycles or chains in a perm */
typedef struct _perm_cycle_t {
        const arch_register_t **elems;       /**< the registers in the cycle */
        int                     n_elems;     /**< number of elements in the cycle */
        perm_type_t             type;        /**< type (CHAIN or CYCLE) */
} perm_cycle_t;

/* Compare the in registers of two register pairs */
static int compare_reg_pair(const void *a, const void *b) {
        const reg_pair_t *pair_a = a;
        const reg_pair_t *pair_b = b;

        if (pair_a->in_reg->index > pair_b->in_reg->index)
                return 1;
        else
                return -1;
}

/* returns the number register pairs marked as checked */
static int get_n_checked_pairs(reg_pair_t *pairs, int n) {
        int i, n_checked = 0;

        for (i = 0; i < n; i++) {
                if (pairs[i].checked)
                        n_checked++;
        }

        return n_checked;
}

/**
 * Gets the node corresponding to a register from an array of register pairs.
 * NOTE: The given registers pairs and the register to look for must belong
 *       to the same register class.
 *
 * @param pairs  The array of register pairs
 * @param n      The number of pairs
 * @param reg    The register to look for
 * @param in_out 0 == look for IN register, 1 == look for OUT register
 * @return The corresponding node or NULL if not found
 */
static ir_node *get_node_for_register(reg_pair_t *pairs, int n, const arch_register_t *reg, int in_out) {
        int i;

        if (in_out) {
                for (i = 0; i < n; i++) {
                        /* out register matches */
                        if (pairs[i].out_reg->index == reg->index)
                                return pairs[i].out_node;
                }
        }
        else {
                for (i = 0; i < n; i++) {
                        /* in register matches */
                        if (pairs[i].in_reg->index == reg->index)
                                return pairs[i].in_node;
                }
        }

        return NULL;
}

/**
 * Gets the index in the register pair array where the in/out register
 * corresponds to reg_idx.
 *
 * @param pairs  The array of register pairs
 * @param n      The number of pairs
 * @param reg    The register index to look for
 * @param in_out 0 == look for IN register, 1 == look for OUT register
 * @return The corresponding index in pairs or -1 if not found
 */
static int get_pairidx_for_regidx(reg_pair_t *pairs, int n, int reg_idx, int in_out) {
        int i;

        if (in_out) {
                for (i = 0; i < n; i++) {
                        /* out register matches */
                        if (pairs[i].out_reg->index == reg_idx)
                                return i;
                }
        }
        else {
                for (i = 0; i < n; i++) {
                        /* in register matches */
                        if (pairs[i].in_reg->index == reg_idx)
                                return i;
                }
        }

        return -1;
}

/**
 * Gets an array of register pairs and tries to identify a cycle or chain starting
 * at position start.
 *
 * @param cycle Variable to hold the cycle
 * @param pairs Array of register pairs
 * @param start Index to start
 * @return The cycle or chain
 */
static perm_cycle_t *get_perm_cycle(perm_cycle_t *cycle, reg_pair_t *pairs, int n, int start) {
        int head         = pairs[start].in_reg->index;
        int cur_idx      = pairs[start].out_reg->index;
        int cur_pair_idx = start;
        int n_pairs_done = get_n_checked_pairs(pairs, n);
        int idx;
        perm_type_t cycle_tp = PERM_CYCLE;

        /* We could be right in the middle of a chain, so we need to find the start */
        while (head != cur_idx) {
                /* goto previous register in cycle or chain */
                cur_pair_idx = get_pairidx_for_regidx(pairs, n, head, 1);

                if (cur_pair_idx < 0) {
                        cycle_tp = PERM_CHAIN;
                        break;
                }
                else {
                        head  = pairs[cur_pair_idx].in_reg->index;
                        start = cur_pair_idx;
                }
        }

        /* assume worst case: all remaining pairs build a cycle or chain */
        cycle->elems    = xcalloc((n - n_pairs_done) * 2, sizeof(cycle->elems[0]));
        cycle->n_elems  = 2;  /* initial number of elements is 2 */
        cycle->elems[0] = pairs[start].in_reg;
        cycle->elems[1] = pairs[start].out_reg;
        cycle->type     = cycle_tp;
        cur_idx         = pairs[start].out_reg->index;

        idx = 2;
        /* check for cycle or end of a chain */
        while (cur_idx != head) {
                /* goto next register in cycle or chain */
                cur_pair_idx = get_pairidx_for_regidx(pairs, n, cur_idx, 0);

                if (cur_pair_idx < 0)
                        break;

                cur_idx = pairs[cur_pair_idx].out_reg->index;

                /* it's not the first element: insert it */
                if (cur_idx != head) {
                        cycle->elems[idx++] = pairs[cur_pair_idx].out_reg;
                        cycle->n_elems++;
                }
                else {
                        /* we are there where we started -> CYCLE */
                        cycle->type = PERM_CYCLE;
                }
        }

        /* mark all pairs having one in/out register with cycle in common as checked */
        for (idx = 0; idx < cycle->n_elems; idx++) {
                cur_pair_idx = get_pairidx_for_regidx(pairs, n, cycle->elems[idx]->index, 0);

                if (cur_pair_idx >= 0)
                        pairs[cur_pair_idx].checked = 1;

                cur_pair_idx = get_pairidx_for_regidx(pairs, n, cycle->elems[idx]->index, 1);

                if (cur_pair_idx >= 0)
                        pairs[cur_pair_idx].checked = 1;
        }

        return cycle;
}

/**
 * Lowers a perm node.  Resolves cycles and creates a bunch of
 * copy and swap operations to permute registers.
 * Note: The caller of this function has to make sure, that irn
 *       is a Perm node.
 *
 * @param irn      The perm node
 * @param block    The block the perm node belongs to
 * @param walk_env The environment
 */
static void lower_perm_node(ir_node *irn, void *walk_env) {
        const arch_register_class_t *reg_class;
        const arch_env_t            *arch_env;
        lower_env_t     *env         = walk_env;
        perm_stat_t    **pstat       = env->pstat;
        int              pstat_idx   = -1;
        int              real_size   = 0;
        int              n, i, pn, do_copy, j, n_ops;
        reg_pair_t      *pairs;
        const ir_edge_t *edge;
        perm_cycle_t    *cycle;
        ir_node         *sched_point, *block, *in[2];
        ir_node         *arg1, *arg2, *res1, *res2;
        ir_node         *cpyxchg = NULL;
        ident           *cls_id;
        DEBUG_ONLY(firm_dbg_module_t *mod;)

        arch_env = env->chord_env->birg->main_env->arch_env;
        do_copy  = env->do_copy;
        DEBUG_ONLY(mod = env->dbg_module;)
        block    = get_nodes_block(irn);

        /*
                Get the schedule predecessor node to the perm
                NOTE: This works with auto-magic. If we insert the
                        new copy/exchange nodes after this node, everything
                        should be ok.
        */
        sched_point = sched_prev(irn);
        DBG((mod, LEVEL_1, "sched point is %+F\n", sched_point));
        assert(sched_point && "Perm is not scheduled or has no predecessor");

        n = get_irn_arity(irn);
        assert(n == get_irn_n_edges(irn) && "perm's in and out numbers different");

        reg_class = arch_get_irn_register(arch_env, get_irn_n(irn, 0))->reg_class;
        cls_id    = new_id_from_str(reg_class->name);
        pairs     = alloca(n * sizeof(pairs[0]));

        if (env->do_stat) {
                /* determine index in statistics */
                for (i = 0; i < env->pstat_n; i++) {
                        if (strcmp(pstat[i]->cls->name, reg_class->name) == 0) {
                                pstat_idx = i;
                                break;
                        }
                }
                assert(pstat_idx >= 0 && "could not determine class index for statistics");

                pstat[pstat_idx]->num_perms++;
                pstat[pstat_idx]->perm_size_ar[n - 1]++;
        }

        /* build the list of register pairs (in, out) */
        i = 0;
        foreach_out_edge(irn, edge) {
                pairs[i].out_node = get_edge_src_irn(edge);
                pn                = get_Proj_proj(pairs[i].out_node);
                pairs[i].in_node  = get_irn_n(irn, pn);

                pairs[i].in_reg  = arch_get_irn_register(arch_env, pairs[i].in_node);
                pairs[i].out_reg = arch_get_irn_register(arch_env, pairs[i].out_node);

                pairs[i].checked = 0;
                i++;
        }

        /* sort the register pairs by the indices of the in registers */
        qsort(pairs, n, sizeof(pairs[0]), compare_reg_pair);

        /* Mark all equal pairs as checked, and exchange the OUT proj with
                the IN node. */
        for (i = 0; i < n; i++) {
                if (pairs[i].in_reg->index == pairs[i].out_reg->index) {
                        DBG((mod, LEVEL_1, "%+F removing equal perm register pair (%+F, %+F, %s)\n",
                                irn, pairs[i].in_node, pairs[i].out_node, pairs[i].out_reg->name));

                        /* We have to check for a special case:
                                The in-node could be a Proj from a Perm. In this case,
                                we need to correct the projnum */
                        if (is_Perm(arch_env, pairs[i].in_node) && is_Proj(pairs[i].in_node)) {
                                set_Proj_proj(pairs[i].out_node, get_Proj_proj(pairs[i].in_node));
                        }

                        /* remove the proj from the schedule */
                        sched_remove(pairs[i].out_node);

                        /* reroute the edges from the proj to the argument */
                        edges_reroute(pairs[i].out_node, pairs[i].in_node, env->chord_env->irg);

                        pairs[i].checked = 1;
                }
        }

        /* Set do_copy to 0 if it's on but we have no free register */
        if (do_copy) {
                do_copy = 0;
        }

        if (env->do_stat && get_n_checked_pairs(pairs, n) < n) {
                pstat[pstat_idx]->num_real_perms++;
                pstat[pstat_idx]->real_perm_size_ar[n - 1]++;
                real_size = n - get_n_checked_pairs(pairs, n);
        }

        hook_be_block_stat_perm(cls_id, reg_class->n_regs, irn, block, n, real_size);

        /* check for cycles and chains */
        while (get_n_checked_pairs(pairs, n) < n) {
                i = 0;

                /* go to the first not-checked pair */
                while (pairs[i].checked) i++;
                cycle = xcalloc(1, sizeof(*cycle));
                cycle = get_perm_cycle(cycle, pairs, n, i);

                DB((mod, LEVEL_1, "%+F: following %s created:\n  ", irn, cycle->type == PERM_CHAIN ? "chain" : "cycle"));
                for (j = 0; j < cycle->n_elems; j++) {
                        DB((mod, LEVEL_1, " %s", cycle->elems[j]->name));
                }
                DB((mod, LEVEL_1, "\n"));

                /* statistics */
                if (env->do_stat) {
                        int n_idx = cycle->n_elems - 1;
                        if (cycle->type == PERM_CHAIN) {
                                pstat[pstat_idx]->num_chains++;
                                pstat[pstat_idx]->chain_len_ar[n_idx]++;
                        }
                        else {
                                pstat[pstat_idx]->num_cycles++;
                                pstat[pstat_idx]->cycle_len_ar[n_idx]++;
                        }
                }

                /* We don't need to do anything if we have a Perm with two
                        elements which represents a cycle, because those nodes
                        already represent exchange nodes */
                if (n == 2 && cycle->type == PERM_CYCLE) {
                        free(cycle);
                        continue;
                }

//TODO: - iff PERM_CYCLE && do_copy -> determine free temp reg and insert copy to/from it before/after
//        the copy cascade (this reduces the cycle into a chain)

                /* build copy/swap nodes from back to front */
                for (i = cycle->n_elems - 2; i >= 0; i--) {
                        arg1 = get_node_for_register(pairs, n, cycle->elems[i], 0);
                        arg2 = get_node_for_register(pairs, n, cycle->elems[i + 1], 0);

                        res1 = get_node_for_register(pairs, n, cycle->elems[i], 1);
                        res2 = get_node_for_register(pairs, n, cycle->elems[i + 1], 1);

                        n_ops = 0;
                        /*
                                If we have a cycle and don't copy: we need to create exchange nodes
                                NOTE: An exchange node is a perm node with 2 INs and 2 OUTs
                                IN_1  = in node with register i
                                IN_2  = in node with register i + 1
                                OUT_1 = out node with register i + 1
                                OUT_2 = out node with register i
                        */
                        if (cycle->type == PERM_CYCLE && !do_copy) {
                                in[0] = arg1;
                                in[1] = arg2;

                                /* At this point we have to handle the following problem:     */
                                /*                                                            */
                                /* If we have a cycle with more than two elements, then       */
                                /* this could correspond to the following Perm node:          */
                                /*                                                            */
                                /*   +----+   +----+   +----+                                 */
                                /*   | r1 |   | r2 |   | r3 |                                 */
                                /*   +-+--+   +-+--+   +--+-+                                 */
                                /*     |        |         |                                   */
                                /*     |        |         |                                   */
                                /*   +-+--------+---------+-+                                 */
                                /*   |         Perm         |                                 */
                                /*   +-+--------+---------+-+                                 */
                                /*     |        |         |                                   */
                                /*     |        |         |                                   */
                                /*   +-+--+   +-+--+   +--+-+                                 */
                                /*   |Proj|   |Proj|   |Proj|                                 */
                                /*   | r2 |   | r3 |   | r1 |                                 */
                                /*   +----+   +----+   +----+                                 */
                                /*                                                            */
                                /* This node is about to be split up into two 2x Perm's       */
                                /* for which we need 4 Proj's and the one additional Proj     */
                                /* of the first Perm has to be one IN of the second. So in    */
                                /* general we need to create one additional Proj for each     */
                                /* "middle" Perm and set this to one in node of the successor */
                                /* Perm.                                                      */

                                DBG((mod, LEVEL_1, "%+F creating exchange node (%+F, %s) and (%+F, %s) with\n",
                                        irn, arg1, cycle->elems[i]->name, arg2, cycle->elems[i + 1]->name));
                                DBG((mod, LEVEL_1, "%+F                        (%+F, %s) and (%+F, %s)\n",
                                        irn, res1, cycle->elems[i]->name, res2, cycle->elems[i + 1]->name));

                                cpyxchg = be_new_Perm(reg_class, env->chord_env->irg, block, 2, in);
                                n_ops++;

                                if (i > 0) {
                                        /* cycle is not done yet */
                                        int pidx = get_pairidx_for_regidx(pairs, n, cycle->elems[i]->index, 0);

                                        /* create intermediate proj */
                                        res1 = new_r_Proj(get_irn_irg(irn), block, cpyxchg, get_irn_mode(res1), 0);

                                        /* set as in for next Perm */
                                        pairs[pidx].in_node = res1;
                                }
                                else {
                                        sched_remove(res1);
                                }

                                sched_remove(res2);

                                set_Proj_pred(res2, cpyxchg);
                                set_Proj_proj(res2, 0);
                                set_Proj_pred(res1, cpyxchg);
                                set_Proj_proj(res1, 1);

                                sched_add_after(sched_point, res1);
                                sched_add_after(sched_point, res2);

                                arch_set_irn_register(arch_env, res2, cycle->elems[i + 1]);
                                arch_set_irn_register(arch_env, res1, cycle->elems[i]);

                                /* insert the copy/exchange node in schedule after the magic schedule node (see above) */
                                sched_add_after(sched_point, cpyxchg);

                                DBG((mod, LEVEL_1, "replacing %+F with %+F, placed new node after %+F\n", irn, cpyxchg, sched_point));

                                /* set the new scheduling point */
                                sched_point = res1;
                        }
                        else {
                                DBG((mod, LEVEL_1, "%+F creating copy node (%+F, %s) -> (%+F, %s)\n",
                                        irn, arg1, cycle->elems[i]->name, res2, cycle->elems[i + 1]->name));

                                cpyxchg = be_new_Copy(reg_class, env->chord_env->irg, block, arg1);
                                arch_set_irn_register(arch_env, cpyxchg, cycle->elems[i + 1]);
                                n_ops++;

                                /* remove the proj from the schedule */
                                sched_remove(res2);

                                /* exchange copy node and proj */
                                exchange(res2, cpyxchg);

                                /* insert the copy/exchange node in schedule after the magic schedule node (see above) */
                                sched_add_after(sched_point, cpyxchg);

                                /* set the new scheduling point */
                                sched_point = cpyxchg;
                        }

                        if (env->do_stat) {
                                hook_be_block_stat_permcycle(cls_id, irn, block, cycle->type == PERM_CHAIN, cycle->n_elems, n_ops);
                        }
                }

                free((void *) cycle->elems);
                free(cycle);
        }



        /* remove the perm from schedule */
        sched_remove(irn);
}



static int get_n_out_edges(const ir_node *irn) {
        const ir_edge_t *edge;
        int cnt = 0;

        foreach_out_edge(irn, edge) {
                cnt++;
        }

        return cnt;
}

static ir_node *belower_skip_proj(ir_node *irn) {
        while(is_Proj(irn))
                irn = get_Proj_pred(irn);
        return irn;
}

static void fix_in(ir_node *irn, ir_node *old, ir_node *nw) {
        int i, n;

        irn = belower_skip_proj(irn);
        n   = get_irn_arity(irn);

        for (i = 0; i < n; i++) {
                if (get_irn_n(irn, i) == old) {
                        set_irn_n(irn, i, nw);
                        break;
                }
        }
}

static void gen_assure_different_pattern(ir_node *irn, be_irg_t *birg, ir_node *other_different) {
        const arch_env_t          *arch_env = birg->main_env->arch_env;
        ir_node                   *in[2], *keep, *cpy, *temp;
        ir_node                   *block = get_nodes_block(irn);
        const arch_register_class_t *cls = arch_get_irn_reg_class(arch_env, other_different, -1);
        FIRM_DBG_REGISTER(firm_dbg_module_t *mod, "firm.be.lower");

        if (arch_irn_is(arch_env, other_different, ignore) || ! mode_is_datab(get_irn_mode(other_different))) {
                DBG((mod, LEVEL_1, "ignore constraint for %+F because other_irn is ignore or not a datab node\n", irn));
                return;
        }

        /* Make a not spillable copy of the different node   */
        /* this is needed because the different irn could be */
        /* in block far far away                             */
        /* The copy is optimized later if not needed         */

        temp = new_rd_Unknown(birg->irg, get_irn_mode(other_different));
        cpy = be_new_Copy(cls, birg->irg, block, temp);
        be_node_set_flags(cpy, BE_OUT_POS(0), arch_irn_flags_dont_spill);

        in[0] = irn;
        in[1] = cpy;

        /* Let the irn use the copy instead of the old other_different */
        fix_in(irn, other_different, cpy);

        /* Add the Keep resp. CopyKeep and reroute the users */
        /* of the other_different irn in case of CopyKeep.   */
        if (get_n_out_edges(other_different) == 0) {
                keep = be_new_Keep(cls, birg->irg, block, 2, in);
        }
        else {
                keep = be_new_CopyKeep_single(cls, birg->irg, block, cpy, irn, get_irn_mode(other_different));
                be_node_set_reg_class(keep, 1, cls);
                edges_reroute(other_different, keep, birg->irg);
        }

        /* after rerouting: let the copy point to the other_different irn */
        set_irn_n(cpy, 0, other_different);

        DBG((mod, LEVEL_1, "created %+F for %+F to assure should_be_different\n", keep, irn));
}

/**
 * Checks if node has a should_be_different constraint in output
 * and adds a Keep then to assure the constraint.
 */
static void assure_different_constraints(ir_node *irn, be_irg_t *birg) {
        const arch_env_t          *arch_env = birg->main_env->arch_env;
        const arch_register_req_t *req;
        arch_register_req_t        req_temp;
        int i, n;

        req = arch_get_register_req(arch_env, &req_temp, irn, -1);

        if (req) {
                if (arch_register_req_is(req, should_be_different)) {
                        gen_assure_different_pattern(irn, birg, req->other_different);
                }
                else if (arch_register_req_is(req, should_be_different_from_all)) {
                        n = get_irn_arity(belower_skip_proj(irn));
                        for (i = 0; i < n; i++) {
                                gen_assure_different_pattern(irn, birg, get_irn_n(belower_skip_proj(irn), i));
                        }
                }
        }
}



/**
 * Calls the functions to assure register constraints.
 *
 * @param irn      The node to be checked for lowering
 * @param walk_env The walker environment
 */
static void assure_constraints_walker(ir_node *irn, void *walk_env) {
        if (is_Block(irn))
                return;

        if (mode_is_datab(get_irn_mode(irn)))
                assure_different_constraints(irn, walk_env);

        return;
}



/**
 * Walks over all nodes to assure register constraints.
 *
 * @param birg  The birg structure containing the irg
 */
void assure_constraints(be_irg_t *birg) {
        irg_walk_blkwise_graph(birg->irg, NULL, assure_constraints_walker, birg);
}



/**
 * Calls the corresponding lowering function for the node.
 *
 * @param irn      The node to be checked for lowering
 * @param walk_env The walker environment
 */
static void lower_nodes_after_ra_walker(ir_node *irn, void *walk_env) {
        lower_env_t      *env      = walk_env;
        const arch_env_t *arch_env = env->chord_env->birg->main_env->arch_env;

        if (!is_Block(irn) && !is_Proj(irn)) {
                if (is_Perm(arch_env, irn)) {
                        lower_perm_node(irn, walk_env);
                }
        }

        return;
}

static void lower_print_perm_stat(lower_env_t *env) {
        int i, j, total_len_chain, total_len_cycle, total_size_perm, total_size_real_perm;

        printf("=== IRG: %s ===\n", get_entity_name(get_irg_entity(env->chord_env->irg)));
        for (i = 0; i < env->pstat_n; i++) {
                if (env->pstat[i]->num_perms == 0)
                        continue;

                printf("CLASS: %s\n", env->pstat[i]->cls->name);
                printf("# total perms:      %d (size:num   -> 1:%d", env->pstat[i]->num_perms, env->pstat[i]->perm_size_ar[0]);

                total_size_perm = env->pstat[i]->perm_size_ar[0];
                for (j = 1; j < env->pstat[i]->cls->n_regs; j++) {
                        total_size_perm += (j + 1) * env->pstat[i]->perm_size_ar[j];
                        printf(", %d:%d", j + 1, env->pstat[i]->perm_size_ar[j]);
                }
                printf(")\n");
                printf("avg perm size:      %.2f\n", env->pstat[i]->num_perms ? (float)total_size_perm / (float)env->pstat[i]->num_perms : 0);

                printf("# real perms:       %d (size:num  -> 1:%d", env->pstat[i]->num_real_perms, env->pstat[i]->real_perm_size_ar[0]);

                total_size_real_perm = env->pstat[i]->real_perm_size_ar[0];
                for (j = 1; j < env->pstat[i]->cls->n_regs; j++) {
                        total_size_real_perm += (j + 1) * env->pstat[i]->real_perm_size_ar[j];
                        printf(", %d:%d", j + 1, env->pstat[i]->real_perm_size_ar[j]);
                }
                printf(")\n");
                printf("avg real perm size: %.2f\n", env->pstat[i]->num_real_perms ? (float)total_size_real_perm / (float)env->pstat[i]->num_real_perms : 0);

                printf("# total chains:     %d (lenght:num -> 1:%d", env->pstat[i]->num_chains, env->pstat[i]->chain_len_ar[0]);

                total_len_chain = env->pstat[i]->chain_len_ar[0];

                for (j = 1; j < env->pstat[i]->cls->n_regs; j++) {
                        total_len_chain += (j + 1) * env->pstat[i]->chain_len_ar[j];
                        printf(", %d:%d", j + 1, env->pstat[i]->chain_len_ar[j]);
                }
                printf(")\n");
                printf("avg chain length:   %.2f\n", env->pstat[i]->num_chains ? (float)total_len_chain / (float)env->pstat[i]->num_chains : 0);
                printf("avg chains/perm:    %.2f\n", env->pstat[i]->num_real_perms ? (float)env->pstat[i]->num_chains / (float)env->pstat[i]->num_real_perms : 0);

                printf("# total cycles:     %d (length:num -> 1:%d", env->pstat[i]->num_cycles, env->pstat[i]->cycle_len_ar[0]);

                total_len_cycle = env->pstat[i]->cycle_len_ar[0];
                for (j = 1; j < env->pstat[i]->cls->n_regs; j++) {
                        total_len_cycle += (j + 1) * env->pstat[i]->cycle_len_ar[j];
                        printf(", %d:%d", j + 1, env->pstat[i]->cycle_len_ar[j]);
                }
                printf(")\n");
                printf("avg cycle length:   %.2f\n", env->pstat[i]->num_cycles ? (float)total_len_cycle / (float)env->pstat[i]->num_cycles : 0);
                printf("avg cycles/perm:    %.2f\n", env->pstat[i]->num_real_perms ? (float)env->pstat[i]->num_cycles / (float)env->pstat[i]->num_real_perms : 0);
        }
}

/**
 * Walks over all blocks in an irg and performs lowering need to be
 * done after register allocation (e.g. perm lowering).
 *
 * @param chord_env The chordal environment containing the irg
 * @param do_copy   1 == resolve cycles with a free reg if available
 */
void lower_nodes_after_ra(be_chordal_env_t *chord_env, int do_copy, int do_stat) {
        lower_env_t env;

        env.chord_env  = chord_env;
        env.do_copy    = do_copy;
        env.do_stat    = do_stat;
        FIRM_DBG_REGISTER(env.dbg_module, "firm.be.lower");

        /* if we want statistics: allocate memory for the data and initialize with 0 */
        if (do_stat) {
                const arch_isa_t *isa = chord_env->birg->main_env->arch_env->isa;
                int i, n = arch_isa_get_n_reg_class(isa);

                env.pstat   = alloca(n * sizeof(env.pstat[0]));
                env.pstat_n = n;

                for (i = 0; i < n; i++) {
                        const arch_register_class_t *cls = arch_isa_get_reg_class(isa, i);
                        int                       n_regs = cls->n_regs;

                        env.pstat[i] = alloca(sizeof(*(env.pstat[0])));
                        memset(env.pstat[i], 0, sizeof(*(env.pstat[0])));

                        env.pstat[i]->perm_size_ar      = alloca(n_regs * sizeof(env.pstat[i]->perm_size_ar[0]));
                        env.pstat[i]->real_perm_size_ar = alloca(n_regs * sizeof(env.pstat[i]->real_perm_size_ar[0]));
                        env.pstat[i]->chain_len_ar      = alloca(n_regs * sizeof(env.pstat[i]->chain_len_ar[0]));
                        env.pstat[i]->cycle_len_ar      = alloca(n_regs * sizeof(env.pstat[i]->cycle_len_ar[0]));

                        memset(env.pstat[i]->perm_size_ar, 0, n_regs * sizeof(env.pstat[i]->perm_size_ar[0]));
                        memset(env.pstat[i]->real_perm_size_ar, 0, n_regs * sizeof(env.pstat[i]->real_perm_size_ar[0]));
                        memset(env.pstat[i]->chain_len_ar, 0, n_regs * sizeof(env.pstat[i]->chain_len_ar[0]));
                        memset(env.pstat[i]->cycle_len_ar, 0, n_regs * sizeof(env.pstat[i]->cycle_len_ar[0]));

                        env.pstat[i]->cls = cls;
                }
        }

        irg_walk_blkwise_graph(chord_env->irg, NULL, lower_nodes_after_ra_walker, &env);

        if (do_stat) {
                lower_print_perm_stat(&env);
        }
}

#undef is_Perm