Subversion Repositories tendra.SVN

/*

    		 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 PROTO_S ( ( 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 */

static exp names[LIMIT];	/* no init needed */ /* records the uses of the control variable */

static int names_index;		/* no init needed */

static int allow_double;	/* no init needed */ /* permit removal of internal test */

static int jumps_out;		/* no init needed */

/* PROCEDURES */

static int  uc_list

    PROTO_N ( (e, n, control, lia, ul, decr) )

    PROTO_T ( exp e X int n X exp control X int lia X exp ul X 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

    PROTO_N ( (e, n, control, lia, ul, decr) )

    PROTO_T ( exp e X int n X exp control X int lia X exp ul X 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)

      allow_double = 0;		/* prevent removal of internal test */

    return n;

  };

  switch (name (e)) {

    case test_tag:

    case testbit_tag:

      if (!isunroll(pt(e))) {	/* flag set and cleared by cond_tag below */

	allow_double = 0;	/* prevent removal of internal test; jump out of loop */

      };

      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 */

	allow_double = 0;	/* prevent removal of internal test; jump out of loop */

      };

      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)

	  allow_double = 0;	/* prevent removal of internal test; assigning to limit */

	if (lia) {

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

	    allow_double = 0;	/* prevent removal of internal test; perhaps assigning to limit */

	  if (name(assdest) == name_tag && !iscaonly(son(assdest)))

	    allow_double = 0;	/* prevent removal of internal test; perhaps assigning to limit */

	};

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

      };

    case name_tag:

      if (son (e) == control) { /* is this the control variable? */

	exp t;

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

	  allow_double = 0;	/* any use but contents -> no test elim */

	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)

	    allow_double = 0;	/* not offset_mult -> no test elim */

	  else

	    names[names_index++] = bro(e);	/* record the use */

#else

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

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

	    allow_double = 0;	/* not offset_mult -> no test elim */

	  else

	    names[names_index++] = bro(e);	/* record the use */

#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

    PROTO_N ( (candidate, body, inc, te) )

    PROTO_T ( exp candidate X exp body X exp inc X 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 */

    exp second_body = copy (body);	/* repeated statement less label, assignment and test */

    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)));

    no (son (bro (son (candidate))))--;	/* decrease label count (increased by copy(te)) */

    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

    PROTO_N ( (var, sha, konst, body, i) )

    PROTO_T ( exp var X shape sha X exp konst X exp body X 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(bro(t), copy(sum), body);	/* replace the offset_mults in body */

      kill_exp(b, b);

      t = q;

    };

    if (t != rest)

      failer("unroll failure");

    kill_exp(sum, sum);

  };

  return body;

}

void unroll_trans

    PROTO_N ( (candidate, body, inc, te, limit, nt, var, konst, reps, times) )

    PROTO_T ( exp candidate X exp body X exp inc X exp te X exp limit X

	      int nt X exp var X exp konst X exp reps X 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);

    exp branches [UNROLL_MAX + 2];	/* 0 - (times-2) are preliminaries

					   (times-1) is test out

					   times is the loop

					   (times+1) is the end */

    exp test_out = copy(te);		/* used to jump out after < times */

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

    exp new_c = me_shint(sha, times*no(konst));	/* used to increment the control variable */

    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(bro(son(bro(var))), new_c, new_c);	/* replace konst by times*konst */

    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

    PROTO_Z ()

{

  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;

}