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/* adv.c -- OpenRISC Custom Unit Compiler, Advanced Optimizations

 *    Copyright (C) 2002 Marko Mlinar, markom@opencores.org

 *

 *    This file is part of OpenRISC 1000 Architectural Simulator.

 *

 *    This program is free software; you can redistribute it and/or modify

 *    it under the terms of the GNU General Public License as published by

 *    the Free Software Foundation; either version 2 of the License, or

 *    (at your option) any later version.

 *

 *    This program is distributed in the hope that it will be useful,

 *    but WITHOUT ANY WARRANTY; without even the implied warranty of

 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *    GNU General Public License for more details.

 *

 *    You should have received a copy of the GNU General Public License

 *    along with this program; if not, write to the Free Software

 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */

#include <stdio.h>

#include <stdlib.h>

#include <stdarg.h>

#include <assert.h>

#include "sim-config.h"

#include "abstract.h"

#include "cuc.h"

#include "insn.h"

#include "support/profile.h"

/* Marks successor of b with mask m */

static void mark_successors (cuc_func *f, int b, int m, int stopb)

{

  if (b < 0 || b == BBID_END) return;

  if (f->bb[b].tmp & m) return;

  f->bb[b].tmp |= m;

  /* mark stopb also; and stop searching -- we will gen new result in stopb */

  if (b == stopb) return;

  mark_successors (f, f->bb[b].next[0], m, stopb);

  mark_successors (f, f->bb[b].next[1], m, stopb);

}

static unsigned long mask (unsigned long c)

{

  if (c) return (1 << (log2 (c) + 1)) - 1;

  else return 0;

}

/* Calculates facts, that are determined by conditionals */

void insert_conditional_facts (cuc_func *f)

{

  int b, i, j;

  int b1, i1, j1;

  cuc_insn n[2];

  for (b = 0; b < f->num_bb; b++) if (f->bb[b].ninsn > 0) {

    cuc_insn *ii = &f->bb[b].insn[f->bb[b].ninsn - 1];

    /* We have following situation

       x <= ...

       sfxx f, x, CONST

       bf ..., f */

    if (ii->type & IT_BRANCH && ii->opt[1] & OPT_REF && REF_BB(ii->op[1]) == b

     && f->INSN(ii->op[1]).opt[2] & OPT_CONST) {

      int ok = 0;

      unsigned long c = f->INSN(ii->op[1]).op[2];

      int rref = f->INSN(ii->op[1]).op[1];

      unsigned long r;

      if (!(f->INSN(ii->op[1]).opt[1] & OPT_REF)) continue;

      r = f->INSN(rref).op[0];

      for (j = 0; j < 2; j++) {

        change_insn_type (&n[j], II_ADD);

        n[j].type = 0;

        n[j].dep = NULL;

        n[j].op[0] = r; n[j].opt[0] = OPT_REGISTER | OPT_DEST;

        n[j].op[1] = 0; n[j].opt[1] = OPT_CONST;

        n[j].op[2] = rref; n[j].opt[2] = OPT_REF;

        n[j].opt[3] = OPT_NONE;

        sprintf (n[j].disasm, "conditional %s fact", j ? "false" : "true");

      }

      /* First get the conditional and two instruction to place after the current BB */

      switch (f->INSN(ii->op[1]).index) {

        case II_SFEQ:

          change_insn_type (&n[0], II_ADD);

          n[0].op[0] = r; n[0].opt[0] = OPT_REGISTER | OPT_DEST;

          n[0].op[1] = 0; n[0].opt[1] = OPT_CONST;

          n[0].op[2] = c; n[0].opt[2] = OPT_CONST;

          ok = 1;

          break;

        case II_SFNE:

          change_insn_type (&n[1], II_ADD);

          n[1].op[0] = r; n[1].opt[0] = OPT_REGISTER | OPT_DEST;

          n[1].op[1] = 0; n[1].opt[1] = OPT_CONST;

          n[1].op[2] = c; n[1].opt[2] = OPT_CONST;

          ok = 2;

          break;

        case II_SFLT:

          change_insn_type (&n[0], II_AND);

          n[0].op[0] = r; n[0].opt[0] = OPT_REGISTER | OPT_DEST;

          n[0].op[1] = rref; n[0].opt[1] = OPT_REF;

          n[0].op[2] = mask (c); n[0].opt[2] = OPT_CONST;

          ok = 1;

          break;

        case II_SFGT:

          change_insn_type (&n[1], II_ADD);

          n[1].op[0] = r; n[1].opt[0] = OPT_REGISTER | OPT_DEST;

          n[1].op[1] = rref; n[1].opt[1] = OPT_REF;

          n[1].op[2] = mask (c + 1); n[1].opt[2] = OPT_CONST;

          ok = 2;

          break;

        case II_SFLE:

          change_insn_type (&n[0], II_AND);

          n[0].op[0] = r; n[0].opt[0] = OPT_REGISTER | OPT_DEST;

          n[0].op[1] = rref; n[0].opt[1] = OPT_REF;

          n[0].op[2] = mask (c); n[0].opt[2] = OPT_CONST;

          ok = 1;

          break;

        case II_SFGE:

          change_insn_type (&n[1], II_ADD);

          n[1].op[0] = r; n[1].opt[0] = OPT_REGISTER | OPT_DEST;

          n[1].op[1] = rref; n[1].opt[1] = OPT_REF;

          n[1].op[2] = mask (c + 1); n[1].opt[2] = OPT_CONST;

          ok = 2;

          break;

        default:

          ok = 0;

          break;

      }

      /* Now add two BBs at the end and relink */

      if (ok) {

        int cnt = 0;

        printf ("%x rref %x cnt %i\n", b, rref, cnt);

        fflush (stdout);

        for (j = 0; j < 2; j++) {

          int nb = f->num_bb++;

          int sb;

          int k;

          assert (nb < MAX_BB);

          f->bb[nb].type = 0;

          f->bb[nb].first = -1; f->bb[nb].last = -1;

          f->bb[nb].prev[0] = b; f->bb[nb].prev[1] = -1;

          sb = f->bb[nb].next[0] = f->bb[b].next[j]; f->bb[nb].next[1] = -1;

          assert (cnt >= 0);

          printf ("%x %x %x rref %x cnt %i\n", b, sb, nb, rref, cnt);

          fflush (stdout);

          assert (sb >= 0);

          f->bb[b].next[j] = nb;

          if (sb != BBID_END) {

            if (f->bb[sb].prev[0] == b) f->bb[sb].prev[0] = nb;

            else if (f->bb[sb].prev[1] == b) f->bb[sb].prev[1] = nb;

            else assert (0);

          }

          f->bb[nb].insn = (cuc_insn *) malloc (sizeof (cuc_insn) * (cnt + 1));

          assert (f->bb[nb].insn);

          f->bb[nb].insn[0] = n[j];

          f->bb[nb].ninsn = cnt + 1;

          f->bb[nb].mdep = NULL;

          f->bb[nb].nmemory = 0;

          f->bb[nb].cnt = 0;

          f->bb[nb].unrolled = 0;

          f->bb[nb].ntim = 0;

          f->bb[nb].selected_tim = -1;

        }

        for (b1 = 0; b1 < f->num_bb; b1++) f->bb[b1].tmp = 0;

        /* Find successor blocks and change links accordingly */

        mark_successors (f, f->num_bb - 2, 2, b);

        mark_successors (f, f->num_bb - 1, 1, b);

        for (b1 = 0; b1 < f->num_bb - 2; b1++) if (f->bb[b1].tmp == 1 || f->bb[b1].tmp == 2) {

          int end;

          if (REF_BB (rref) == b1) end = REF_I (rref) + 1;

          else end = f->bb[b1].ninsn;

          for (i1 = 0; i1 < end; i1++)

            for (j1 = 0; j1 < MAX_OPERANDS; j1++)

              if (f->bb[b1].insn[i1].opt[j1] & OPT_REF && f->bb[b1].insn[i1].op[j1] == rref)

                f->bb[b1].insn[i1].op[j1] = REF (f->num_bb - f->bb[b1].tmp, 0);

        }

        print_cuc_bb (f, "FACT");

      }

    }

  }

}

static unsigned long max_op (cuc_func *f, int ref, int o)

{

  if (f->INSN(ref).opt[o] & OPT_REF) return f->INSN(f->INSN(ref).op[o]).max;

  else if (f->INSN(ref).opt[o] & OPT_CONST) return f->INSN(ref).op[o];

  else if (f->INSN(ref).opt[o] & OPT_REGISTER) return 0xffffffff;

  else assert (0);

}

/* Returns maximum value, based on inputs */

static unsigned long calc_max (cuc_func *f, int ref)

{

  cuc_insn *ii = &f->INSN(ref);

  if (ii->type & IT_COND) return 1;

  switch (ii->index) {

    case II_ADD : return MIN ((unsigned long long) max_op (f, ref, 1)

                            + (unsigned long long)max_op (f, ref, 2), 0xffffffff);

    case II_SUB : return 0xffffffff;

    case II_AND : return MIN (max_op (f, ref, 1), max_op (f, ref, 2));

    case II_OR  : return max_op (f, ref, 1) | max_op (f, ref, 2);

    case II_XOR : return max_op (f, ref, 1) | max_op (f, ref, 2);

    case II_MUL : return MIN ((unsigned long long) max_op (f, ref, 1)

                            * (unsigned long long)max_op (f, ref, 2), 0xffffffff);

    case II_SLL : if (ii->opt[2] & OPT_CONST) return max_op (f, ref, 1) << ii->op[2];

                  else return max_op (f, ref, 1);

    case II_SRA : return max_op (f, ref, 1);

    case II_SRL : if (ii->opt[2] & OPT_CONST) return max_op (f, ref, 1) >> ii->op[2];

                  else return max_op (f, ref, 1);

    case II_LB  : return 0xff;

    case II_LH  : return 0xffff;

    case II_LW  : return 0xffffffff;

    case II_SB  :

    case II_SH  :

    case II_SW  : return 0;

    case II_SFEQ:

    case II_SFNE:

    case II_SFLE:

    case II_SFLT:

    case II_SFGE:

    case II_SFGT: return 1;

    case II_BF  : return 0;

    case II_LRBB: return 1;

    case II_CMOV: return MAX (max_op (f, ref, 1), max_op (f, ref, 2));

    case II_REG : return max_op (f, ref, 1);

    case II_NOP : assert (0);

    case II_CALL: assert (0);

    default:  assert (0);

  }

  return -1;

}

/* Width optimization -- detect maximum values;

   these values are actually estimates, since the problem

   is to hard otherwise...

   We calculate these maximums iteratively -- we are slowly

   approaching final solution. This algorithm is surely finite,

   but can be very slow; so we stop after some iterations;

   normal loops should be in this range */

void detect_max_values (cuc_func *f)

{

  int b, i, j;

  int modified = 0;

  int iteration = 0;

  for (b = 0; b < f->num_bb; b++) {

    for (i = 0; i < f->bb[b].ninsn; i++) f->bb[b].insn[i].max = 0;

    f->bb[b].tmp = 1;

  }

  /* Repeat until something is changing */

  do {

    modified = 0;

    for (b = 0; b < f->num_bb; b++) {

      if (f->bb[b].tmp) {

        for (i = 0; i < f->bb[b].ninsn; i++) {

          unsigned long m = calc_max (f, REF (b, i));

          if (m > f->bb[b].insn[i].max) {

            f->bb[b].insn[i].max = m;

            modified = 1;

          }

        }

      }

    }

    if (iteration++ > CUC_WIDTH_ITERATIONS) break;

  } while (modified);

  /* Something bad has happened; now we will assign 0xffffffff to all unsatisfied

     instructions; this one is stoppable in O(n ^ 2) */

  if (iteration > CUC_WIDTH_ITERATIONS) {

    do {

      modified = 0;

      for (b = 0; b < f->num_bb; b++)

        for (i = 0; i < f->bb[b].ninsn; i++) {

          unsigned long m = calc_max (f, REF (b, i));

          if (m > f->bb[b].insn[i].max) {

            f->bb[b].insn[i].max = 0xffffffff;

            modified = 1;

          }

        }

    } while (modified);

  }

  cucdebug (1, "detect_max_values %i iterations\n", iteration);

}