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/*

 * Copyright (c) 2002-2006 The TenDRA Project <http://www.tendra.org/>.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 * 1. Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright notice,

 *    this list of conditions and the following disclaimer in the documentation

 *    and/or other materials provided with the distribution.

 * 3. Neither the name of The TenDRA Project nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific, prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS

 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;

 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,

 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR

 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF

 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * $Id$

 */

/*

    		 Crown Copyright (c) 1997

    This TenDRA(r) Computer Program is subject to Copyright

    owned by the United Kingdom Secretary of State for Defence

    acting through the Defence Evaluation and Research Agency

    (DERA).  It is made available to Recipients with a

    royalty-free licence for its use, reproduction, transfer

    to other parties and amendment for any purpose not excluding

    product development provided that any such use et cetera

    shall be deemed to be acceptance of the following conditions:-

        (1) Its Recipients shall ensure that this Notice is

        reproduced upon any copies or amended versions of it;

        (2) Any amended version of it shall be clearly marked to

        show both the nature of and the organisation responsible

        for the relevant amendment or amendments;

        (3) Its onward transfer from a recipient to another

        party shall be deemed to be that party's acceptance of

        these conditions;

        (4) DERA gives no warranty or assurance as to its

        quality or suitability for any purpose and DERA accepts

        no liability whatsoever in relation to any use to which

        it may be put.

*/

/**********************************************************************

$Author: release $

$Date: 1998/01/17 15:55:47 $

$Revision: 1.1.1.1 $

$Log: unroll.c,v $

 * Revision 1.1.1.1  1998/01/17  15:55:47  release

 * First version to be checked into rolling release.

 *

 * Revision 1.2  1995/09/11  13:58:41  currie

 * gcc pedantry

 *

 * Revision 1.1  1995/04/06  10:44:05  currie

 * Initial revision

 *

***********************************************************************/

#include "config.h"

#include "common_types.h"

#include "basicread.h"

#include "exp.h"

#include "expmacs.h"

#include "tags.h"

#include "installglob.h"

#include "externs.h"

#include "check_id.h"

#include "check.h"

#include "me_fns.h"

#include "install_fns.h"

#include "shapemacs.h"

#include "unroll.h"

static int unroll_complex(exp, int, exp, int, exp, int);

/* MACROS */

#define LIMIT 55

#define SIMPLE_LIMIT 0

#define UNROLL_MAX 16

#define UNROLL_BY 4

/* VARIABLES */

/* All variables initialised */

/* records the uses of the control variable */

static exp names[LIMIT];	/* no init needed */

static int names_index;		/* no init needed */

/* permit removal of internal test */

static int allow_double;	/* no init needed */

static int jumps_out;		/* no init needed */

/* PROCEDURES */

static int

uc_list(exp e, int n, exp control, int lia, exp ul, int decr)

{

	int c = unroll_complex(e, n, control, lia, ul, decr);

	if (c < 0 || last(e)) {

		return c;

	}

	return uc_list(bro(e), c, control, lia, ul, decr);

}

static int

unroll_complex(exp e, int n, exp control, int lia, exp ul, int decr)

{

	/* e = body - repeated statement less label */

	/* n = complexity maximum */

	/* control = variable declaration for control variable */

	/* lia = boolean, limit is aliased */

	/* ul = variable declaration for limit if not aliased */

	/* decr = unit to decrement by */

	if (n < 0) {

		return - 1;	/* complexity exceeded */

	}

	if (son(e) == nilexp) {

		if (name(e) == goto_tag) {

			/* prevent removal of internal test */

			allow_double = 0;

		}

		return n;

	}

	switch (name(e)) {

	case test_tag:

	case testbit_tag:

		if (!isunroll(pt(e))) {

			/* flag set and cleared by cond_tag below */

			/* prevent removal of internal test; jump out of loop */

			allow_double = 0;

		}

		return uc_list(son(e), n - decr, control, lia, ul, decr);

	case goto_tag:

		if (!isunroll(pt(e))) {

			/* flag set and cleared by cond_tag below */

			/* prevent removal of internal test; jump out of loop */

			allow_double = 0;

		}

		return n - 1;

	case cond_tag: {

		int t;

		setunroll(bro(son(e)));		/* mark internal label */

		if (name(sh(son(e))) == bothd) {

			t = unroll_complex(son(e), n - (4 * decr), control, lia,

					   ul, 0);

			t = unroll_complex(bro(son(e)), t - decr, control, lia,

					   ul, decr);

		} else {

			t = unroll_complex(son(e), n - decr, control, lia, ul,

					   decr);

			t = unroll_complex(bro(son(e)), t - decr, control, lia,

					   ul, decr);

		}

		clearunroll(bro(son(e)));	/* unmark it */

		return t;

	}

	case ass_tag:

	case assvol_tag: {

		exp assdest = son(e);	/* destination of assignment */

		if (name(assdest) == name_tag && son(assdest) == ul) {

			/* prevent removal of internal test; assigning to

			 * limit */

			allow_double = 0;

		}

		if (lia) {

			if (name(assdest) == name_tag && !isvar(son(assdest))) {

				/* prevent removal of internal test; perhaps

				 * assigning to limit */

				allow_double = 0;

			}

			if (name(assdest) == name_tag &&

			    !iscaonly(son(assdest))) {

				/* prevent removal of internal test; perhaps

				 * assigning to limit */

				allow_double = 0;

			}

		}

		return uc_list(son(e), n - decr, control, lia, ul, decr);

	}

	case name_tag:

		/* is this the control variable? */

		if (son(e) == control) {

			exp t;

			if (!last(e) || name(bro(e)) != cont_tag) {

				/* any use but contents -> no test elim */

				allow_double = 0;

			} else {

				/* it is a cont */

				t = bro(e);

			}

#if isalpha

				if (!last(t) || name(bro(t)) != chvar_tag ||

				    last(bro(t)) ||

				    name(bro(bro(t))) != val_tag ||

				    !last(bro(bro(t))) ||

				    name(bro(bro(bro(t)))) != offset_mult_tag) {

					/* not offset_mult -> no test elim */

					allow_double = 0;

				} else {

					/* record the use */

					names[names_index++] = bro(e);

				}

#else

				if (last(t) || name(bro(t)) != val_tag ||

				    !last(bro(t)) ||

				    name(bro(bro(t))) != offset_mult_tag) {

					/* not offset_mult -> no test elim */

					allow_double = 0;

				} else {

					/* record the use */

					names[names_index++] = bro(e);

				}

#endif

			}

		return n - decr;

	case apply_tag:

	case solve_tag:

		return -1;	/* no unroll */

	case case_tag:

		return unroll_complex(son(e), n - decr, control, lia, ul, decr);

	case string_tag:

	case env_offset_tag:

	case general_env_offset_tag:

		return n - decr;	/* decrease the complexity count */

	case top_tag:

	case prof_tag:

	case clear_tag:

		return n;

	case labst_tag:

		return unroll_complex(bro(son(e)), n, control, lia, ul, decr);

	case seq_tag:

		return uc_list(son(e), n, control, lia, ul, decr);

	case round_tag:

	case fplus_tag:

	case fminus_tag:

	case fmult_tag:

	case fdiv_tag:

	case fabs_tag:

	case fneg_tag:

	case fpower_tag:

	case fmax_tag:

	case fmin_tag:

	case float_tag:

	case chfl_tag:

		return uc_list (son(e), n - (16 * decr), control, lia, ul,

				decr);	/* heavy flpt ops */

	default:

		return uc_list (son(e), n - decr, control, lia, ul, decr);	/* other ops decrease complexity by 1 */

	}

}

void

simple_unroll(exp candidate, exp body, exp inc, exp te)

{

	/* candidate = rep_tag */

	/* body = repeated statement less label, assignment and test */

	/* inc = the single assignment to the control variable */

	/* te = the final test - only jump to repeat label */

	/* repeated statement less label, assignment and test */

	exp second_body = copy(body);

	exp second_inc = copy(inc);	/* assignment to control */

	exp second_test = copy(te);

	exp z = getexp(f_top, te, 0, nilexp, nilexp, 0, 0, 0);

	exp seq = getexp(f_top, bro(son(candidate)), 1, z, nilexp, 0, 0,

			 seq_tag);

	exp cond_labst;

	exp cl1, mt;

	exp cond, f;

	exp *point;

	float freq = fno(bro(son(candidate)));

	/* decrease label count (increased by copy(te)) */

	no(son(bro(son(candidate))))--;

	setlast(second_inc);

	bro(second_inc) = z;

	clearlast(second_body);

	bro(second_body) = second_inc;

	clearlast(second_test);

	bro(second_test) = second_body;

	clearlast(inc);

	bro(inc) = second_test;

	clearlast(body);

	bro(body) = inc;

	son(z) = body;

	setlast(te);

	bro(te) = seq;

	bro(son(bro(son(candidate)))) = seq;

	/*

	   candidate

	   rep

	   x	labst

	   1 use	seq

	   body	inc	second_test	second_body	second_inc

	 */

	cond_labst = getexp(f_top, nilexp, 1, nilexp, nilexp, 0, 0, labst_tag);

	fno(cond_labst) = (float)(freq / 20.0);

	mt = getexp(f_top, cond_labst, 1, nilexp, nilexp, 0, 0, top_tag);

	cl1 = getexp(f_top, mt, 0, nilexp, nilexp, 0, 1, clear_tag);

	son(cond_labst) = cl1;

	pt(second_test) = cond_labst;

	settest_number(second_test, (int)int_inverse_ntest[test_number(te)]);

	cond = getexp(f_top, bro(candidate), (int)(last(candidate)), candidate,

		      nilexp, 0, 0, cond_tag);

	bro(cond_labst) = cond;

	f = father(candidate);

	point = refto(f, candidate);

	*point = cond;

	clearlast(candidate);

	bro(candidate) = cond_labst;

	/*

	   cond

	   cond

	   rep				labst(ln)

	   x	labst			1 use	top

	   1 use	seq

	   body	inc	second_test(invert, ln)	second_body	second_inc

	 */

	setunrolled(candidate);

	return;

}

static exp

inc_offset(exp var, shape sha, exp konst, exp body, int i)

{

	exp sum, t;

	exp id = son(var);

	exp rest = pt(id);

	body = copy(body);

	if (names_index > 0) {

		/* count of offset_mult uses of control variable */

		t = pt(id);

		sum = me_u3(sha, copy(var), cont_tag);

		sum = hold_check(me_b3(sha, sum, me_shint(sha, i * no(konst)),

				       plus_tag));	/* variable + i */

		for (i = 0; i < names_index; ++i) {

			exp q = pt(t);

			exp b = bro(t);

			/* replace the offset_mults in body */

			replace(bro(t), copy(sum), body);

			kill_exp(b, b);

			t = q;

		}

		if (t != rest) {

			failer("unroll failure");

		}

		kill_exp(sum, sum);

	}

	return body;

}

void

unroll_trans(exp candidate, exp body, exp inc, exp te, exp limit, int nt,

	     exp var, exp konst, exp reps, int times)

{

	/* candidate = rep_tag */

	/* body = repeated statement less label, assignment and test */

	/* inc = the single assignment to the control variable */

	/* te = the final test - only jump to repeat label */

	/* limit = the limit exp */

	/* nt = the test number */

	/* var = name_tag for control variable */

	/* konst = the value added to the control variable */

	/* reps = current element of the repeat list */

	/* times = no of times to unroll */

	float freq = fno(bro(son(candidate)));

	if (allow_double && no(konst) == 1 &&

	    /* allow_double==0 prevents test elimination */

	    (nt == (int)f_greater_than || nt == (int)f_greater_than_or_equal) &&

	    /* the permitted tests - we are counting upwards */

	    ((name(limit) == name_tag && !isvar(son(limit))) ||

	     name(limit) == val_tag ||

	     (name(limit) == cont_tag && name(son(limit)) == name_tag &&

	      isvar(son(son(limit)))))	/* permitted forms of limit */

	   ) {

		/* unroll and remove the internal increment and test */

		int i;

		shape sha = sh(konst);

		/* 0 - (times - 2) are preliminaries (times - 1) is test out

		 * times is the loop (times + 1) is the end */

		exp branches [UNROLL_MAX + 2];

		/* used to jump out after < times */

		exp test_out = copy(te);

		exp temp, temp1, bc, repeater, lrep, res, id, temp2;

		/* used to increment the control variable */

		exp new_c = me_shint(sha, times * no(konst));

		settest_number(test_out,

			       (int)int_inverse_ntest[test_number(test_out)]);

		for (i = 0; i < times + 2; ++i) {

			/* set up labst for branches */

			exp lia = me_shint(sha, (((i > 1) &&

						  (i < (times - 1))) ||

						 i >= times) ? 2 : 1);

			exp li = getexp(f_bottom, nilexp, 0, lia, nilexp, 0, 0,

					labst_tag);

			fno(li) = (float)(freq / 20.0);

			name(lia) = clear_tag;

			clearlast(lia);

			branches[i] = li;

		}

		SET(branches);

		sh(branches[times+1]) = f_top;

		for (i = 0; i < times - 1; ++ i) {

			/* set up preliminaries */

			exp sub = me_b3(f_top, copy(body), copy(inc), 0);

			exp seq = me_b3(f_bottom, sub,

					getexp(f_bottom, nilexp, 0, nilexp,

					       branches[i + 1], 0, 0, goto_tag),

					seq_tag);

			bro(son(branches[i])) = seq;

			setlast(seq);

			bro(seq) = branches[i];

		}

		pt(test_out) = branches[times+1];

		temp = me_u3(f_top, test_out, 0);

		temp = me_b3(f_bottom, temp,

			     getexp(f_bottom, nilexp, 0, nilexp,

				    branches[times], 0, 0, goto_tag), seq_tag);

		bro(son(branches[times - 1])) = temp;

		setlast(temp);

		bro(temp) = branches[times - 1];

		temp = copy(body);

		temp1 = temp;

		if (jumps_out) {

			bro(temp1) = copy(inc);

			clearlast(temp1);

			temp1 = bro(temp1);

		}

		for (i = 1; i < times - 1; ++i) {

			if (jumps_out) {

				bro(temp1) = copy(body);

			} else {

				bro(temp1) = inc_offset(var, sha, konst, body,

							i);

			}

			clearlast(temp1);

			temp1 = bro(temp1);

			if (jumps_out) {

				bro(temp1) = copy(inc);

				clearlast(temp1);

				temp1 = bro(temp1);

			}

		}

		bc = getexp(f_top, nilexp, 0, temp, nilexp, 0, 0, 0);

		setlast(temp1);

		bro(temp1) = bc;

		if (jumps_out) {

			bc = me_b3(f_top, bc, copy(body), seq_tag);

		} else {

			bc = me_b3(f_top, bc, inc_offset(var, sha, konst, body,

							 i), seq_tag);

			kill_exp(body, body);

		}

		if (jumps_out) {

			kill_exp(new_c, new_c);

		} else {

			/* replace konst by times * konst */

			replace(bro(son(bro(var))), new_c, new_c);

		}

		temp = me_b3(f_top, bc, inc, 0);

		temp = me_b3(f_top, temp, te, seq_tag);

		lrep = me_b3(f_top, me_shint(sha, 1), temp, labst_tag);

		fno(lrep) = freq / (float)times;

		name(son(lrep)) = clear_tag;

		repeater = me_b3(f_top, f_make_top(), lrep, rep_tag);

		son(reps) = repeater;

		pt(te) = lrep;	/* label in repeater */

		pt(test_out) = branches[times+1];

		temp = f_make_top();

		bro(son(branches[times + 1])) = temp;

		setlast(temp);

		bro(temp) = branches[times + 1];

		temp = me_u3(f_top, repeater, 0);

		temp = me_b3(f_bottom, temp,

			     getexp(f_bottom, nilexp, 0, nilexp,

				    branches[times + 1], 0, 0, goto_tag),

			     seq_tag);

		bro(son(branches[times])) = temp;

		setlast(temp);

		bro(temp) = branches[times];

		temp = me_u3(sha, copy(var), cont_tag);

		temp1 = copy(limit);

		sh(temp1) = sha;

		temp = hold_check(me_b3(sha, temp1, temp, minus_tag));

		if (nt == (int)f_greater_than) {

			temp = hold_check(me_b3(sha, temp, me_shint(sha, 1),

						plus_tag));

		}

		temp = hold_check(me_b3(sha, temp, me_shint(sha, times - 1),

					and_tag));

		id = me_startid(sha, temp, 0);

		temp = getexp(f_top, nilexp, 0, me_obtain(id), branches[times],

			      0, 0, test_tag);

		settest_number(temp, f_not_equal);

		bro(son(temp)) = me_shint(sha, 0);

		setlast(bro(son(temp)));

		bro(bro(son(temp))) = temp;

		temp1 = temp;

		for (i = 1; i < (times - 1); ++i) {

			temp2 = getexp(f_top, nilexp, 0, me_obtain(id),

				       branches[times - i - 1], 0, 0, test_tag);

			settest_number(temp2, f_not_equal);

			bro(son(temp2)) = me_shint(sha, i);

			setlast(bro(son(temp2)));

			bro(bro(son(temp2))) = temp2;

			settest_number(temp, f_not_equal);

			clearlast(temp1);

			bro(temp1) = temp2;

			temp1 = temp2;

		}

		bc = getexp(f_top, nilexp, 0, temp, nilexp, 0, 0, 0);

		setlast(temp1);

		bro(temp1) = bc;

		bc = me_b3(f_bottom, bc,

			   getexp(f_bottom, nilexp, 0, nilexp, branches[0], 0,

				  0, goto_tag), seq_tag);

		id = me_complete_id(id, bc);

		temp1 = id;

		for (i = 0; i < (times + 2); ++i) {

			bro(temp1) = branches[i];

			clearlast(temp1);

			temp1 = bro(temp1);

		}

		res = getexp(f_top, nilexp, 0, id, nilexp, 0, 0, solve_tag);

		setlast(temp1);

		bro(temp1) = res;

		setunrolled(repeater);

		replace(candidate, res, res);

	}

#if is80x86

	else {

		simple_unroll(candidate, body, inc, te);

	}

#endif

	return;

}

void

unroller(void)

{

  exp reps = repeat_list;

  exp candidate;

  exp labst;

  exp rb;

  while (reps != nilexp) {

    if (no(reps) == 0 && son(reps) != nilexp && name(son(reps)) == rep_tag) {

      /* this is a leaf repeat node */

      candidate = son(reps);		/* this is the repeat */

      labst = bro(son(candidate));	/* the repeated statement */

      rb = bro(son(labst));		/* the repeated statement less label */

      if (name(son(candidate)) == top_tag && no(son(labst)) == 1 &&

	  name(rb) == seq_tag && name(bro(son(rb))) == seq_tag) {

/*

	rep_tag

	top_tag	labst_tag

	count		seq_tag

*/

	exp final = bro(son(rb));

	exp body = son(son(rb));

	exp ass = son(son(final));

	exp te = bro(son(final));

	if (name(ass) == ass_tag && name(te) == test_tag) {

/*

	rep_tag

	top_tag	labst_tag

	count		seq_tag

	body	0	test_tag = te

	ass_tag = ass

*/

	  exp dest = son(ass);

	  exp val = bro(dest);

	  if (name(dest) == name_tag && isvar(son(dest)) &&

	      iscaonly(son(dest)) && shape_size(sh(val)) == 32) {

/*

	rep_tag

	top_tag	labst_tag

	count		seq_tag

	body	0	test_tag = te

	ass_tag = ass

	name = dest	val (32)

	var & ca

*/

	    if (name(val) == plus_tag && name(son(val)) == cont_tag &&

		name(son(son(val))) == name_tag &&

		son(son(son(val))) == son(dest) &&

		name(bro(son(val))) == val_tag) {

/*

	rep_tag

	top_tag	labst_tag

	count		seq_tag

	body	0	test_tag = te

	ass_tag = ass

	name = dest	plus_tag =val (32)

	var & ca	cont_tag	val_tag

	name_tag -> dest

*/

	      exp konst = bro(son(val));

	      int nt = (int)test_number(te);

	      if (name(son(te)) == cont_tag && name(son(son(te))) == name_tag &&

		  pt(te) == labst && son(son(son(te))) == son(dest)) {

/*

	rep_tag

	top_tag	labst_tag

	count	seq_tag

	body	0	test_tag(nt, labst) = te

	ass_tag = ass	cont_tag

	name = dest	plus_tag =val (32)	name_tag -> dest

	var & ca	cont_tag val_tag = konst

	name_tag -> dest

*/

		int count;

		exp limit = bro(son(te));

		exp unaliased_limit = nilexp;

		int limit_is_aliased = 0;

		if (name(limit) == cont_tag && name(son(limit)) == name_tag &&

		    isvar(son(son(limit)))) {

/*

	rep_tag

	top_tag	labst_tag

	count	seq_tag

	body	0	test_tag(nt, labst) = te

	ass_tag = ass	cont_tag	cont_tag = limit

	name = dest	plus_tag =val (32)	name_tag -> dest

	var & ca	cont_tag val_tag = konst

	name_tag -> dest

*/

		  if (iscaonly(son(son(limit)))) {

		    unaliased_limit = son(son(limit));

		  } else {

		    limit_is_aliased = 1;

		  }

		}

		names_index = 0;

		allow_double = 1;

		jumps_out = 0;

		count = unroll_complex(body, LIMIT, son(dest), limit_is_aliased,

				       unaliased_limit, 1);

		if (count >= 0) {

		  unroll_trans(candidate, body, ass, te, limit, nt, dest, konst,

			       reps, UNROLL_BY);

		}

	      }

	    } else {

	      int count;

	      names_index = 0;

	      allow_double = 0;

	      count = unroll_complex(body, SIMPLE_LIMIT, nilexp, 0, nilexp, 1);

	      if (count >= 0) {

	        simple_unroll(candidate, body, ass, te);

	      }

  	    }

	  }

	}

      }

    }

    reps = pt(reps);

  }

  return;

}