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/*

 * Copyright (c) 2002-2005 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.

 *

 * $Id$

 */

/*

    Copyright (c) 1993 Open Software Foundation, Inc.

    All Rights Reserved

    Permission to use, copy, modify, and distribute this software

    and its documentation for any purpose and without fee is hereby

    granted, provided that the above copyright notice appears in all

    copies and that both the copyright notice and this permission

    notice appear in supporting documentation.

    OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING

    ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A

    PARTICULAR PURPOSE.

    IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR

    CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM

    LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,

    NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION

    WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

*/

/*

    		 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: 1998/02/04 15:49:13 $

$Revision: 1.2 $

$Log: weights.c,v $

 * Revision 1.2  1998/02/04  15:49:13  release

 * Added OSF copyright message.

 *

 * Revision 1.1.1.1  1998/01/17  15:55:58  release

 * First version to be checked into rolling release.

 *

 * Revision 1.2  1996/10/04  16:05:06  pwe

 * add banners and mod for PWE ownership

 *

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

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

		weights.c

	The main procedure here is weightsv which determines

the allocation of s regs. It considers which of those tags not already

allocated to a t reg by scan, are best put in an s register. The same

conditions as for t regs apply as to the suitability of the tags for registers.

Weights estimates the usage of each tag and hence the amount that would

be saved if it were held in an s reg. Thus it computes break points for

register allocation for later use by reg_alloc.

	The type weights consists of two arrays of integers. In the first

array each integer corresponds to a fixpnt reg and the second arrays'

integers correspond to floating point regs.

	At the end of a call of weights on an ident exp the props field

of the ident may still contain inreg_bits or infreg_bits, set by scan, to

indicate that a t reg should be used. Otherwise number of ident is set up to

represent the break point for allocation. A similar process occurs for

proc parameters which have the break value in the forweights field

of the parapair of the corresponding procrec. This value has three

meanings:

	1) The ident (or parameter) defines a fixpnt value and number

of ident (forweights of parpair) is an integer brk with the interpretation

that if there are at least brk fixpt s registers unallocated at this point then

one will be used for this tag (parameter).

	2) As 1 but for floating point values.

	3) number of ident = 100 in which case allocate value on the

stack, (this is obviously always available for parameters).

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

#include "config.h"

#include "memtdf.h"

#include "exptypes.h"

#include "exp.h"

#include "expmacs.h"

#include "tags.h"

#include "localtypes.h"

#include "procrectypes.h"

#include "procrecs.h"

#include "bitsmacs.h"

#include "maxminmacs.h"

#include "regable.h"

#include "shapemacs.h"

#include "myassert.h"

#include "weights.h"

static CONST weights zeroweights =

{

  { 0.0	/* , ... */ },

  { 0.0	/* , ... */ }

};

weights weightsv(double, exp);

weights add_weights(weights * w1, weights * w2)

{

  /* sum of weights */

  weights r;

  long i;

  for (i = 0; i < wfixno; ++i)

  {

   (r.fix)[i] = (w1->fix)[i] + (w2->fix)[i];

  }

  for (i = 0; i < wfloatno; ++i)

  {

   (r.floating)[i] = (w1->floating)[i] + (w2->floating)[i];

  }

  return(r);

}

wp max_weights(double loc, weights * ws, bool fix)

{

  /*

   * loc is the usage count of a tag, ws is the weights computed for the scope

   * of the tag and fix distinguishes between fix and float. This computes the

   * weights for the declaration and a break point for register allocation

   * which gives the number of available regs for which it is worthwhile to

   * allocate this tag into a reg ("regged"). This proc is the source of all

   * non-zero weights. NB loc may be negative since using a s-reg will involve

   * a dump and restore.

   */

  long bk = wfixno + 1;

  long i;

  float *w = (ws->fix);		/* w[i] = greatest usage of (i+1) inner fixed tags  */

  wp res;

  float *pw = & (((res.wp_weights).fix)[0]);

  if (fix)

  {

    for (i = 0; i < wfixno; ++i)

    {

      if (i == 0)

      {

	if (loc > w[i])

	{

	  /* this tag has higher usage than any inner one ... */

	  pw[i] = loc;

	  bk = i;		/* ... so it's regged in pref to others */

	}

	else

	  pw[i] = w[i];

      }

      else

      {

	if ((loc + w[i - 1]) > w[i])

	{

	  /*

	   * this tag and i inner ones have higher usage than any other (i+1)

	   * inner ones ...

	   */

	  pw[i] = loc + w[i - 1];

	  if (i < bk)

	    bk = i;

	  /*

	   * ... so it and i inner ones are regged in preference to any other

	   * (i+1) inner ones

	   */

	}

	else

	  pw[i] = w[i];

      }

    }

    res.fix_break = bk;

  }

  else

  {

    for (i = 0; i < wfixno; ++i)

    {

      pw[i] = w[i];

    }

  }

  res.fix_break = bk;

  bk = wfloatno + 1;

  w = (ws->floating);

  pw = & (((res.wp_weights).floating)[0]);

  if (!fix)

  {				/* same algorithm for float regs as fixed regs */

    for (i = 0; i < wfloatno; ++i)

    {

      if (i == 0)

      {

	if (loc > w[i])

	{

	  pw[i] = loc;

	  bk = i;

	}

	else

	  pw[i] = w[i];

      }

      else

      {

	if ((loc + w[i - 1]) > w[i])

	{

	  pw[i] = loc + w[i - 1];

	  if (i < bk)

	    bk = i;

	}

	else

	  pw[i] = w[i];

      }

    }

  }

  else

  {

    for (i = 0; i < wfloatno; ++i)

    {

      pw[i] = w[i];

    }

  }

  res.float_break = bk;

  return res;

}

weights mult_weights(double m, weights * ws)

{

  /*

   * multiply weights by scalar - non overflowing

   */

  weights res;

  float *r = & (res.fix)[0];

  float *w = ws->fix;

  long i;

  for (i = 0; i < wfixno; ++i)

  {

    r[i] = w[i]* m;

  }

  r = & (res.floating)[0];

  w = ws->floating;

  for (i = 0; i < wfloatno; ++i)

  {

    r[i] = w[i]* m;

  }

  return(res);

}

weights add_wlist(double scale, exp re)

{				/* sum of  weights of list re */

  weights w, w1;

  exp r = re;

  if (r == nilexp)

  {

    return zeroweights;

  }

  else if (last(r))

  {

    return(weightsv(scale, r));

  }

  else

  {

    w = weightsv(scale, r);

    do

    {

      r = bro(r);

      w1 = weightsv(scale, r);

      w = add_weights(&w, &w1);

    } while (!last(r));

    return w;

  }

}

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

	weightsv

This procedure estimates the usage of tags and parameters to help

determine whether they can advantageously be placed in s registers.

The parameter scale allows more importance to be placed on usage

inside 'for' loops for example. The procedure reg_alloc in reg_alloc.c

finally determines the actual choice of s reg and recodes the number

field of an ident.

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

weights weightsv(double scale, exp e)

{

tailrecurse:

  switch (name(e))

  {

  case name_tag:

    {

      exp s = son(e);

      if (name(s) == ident_tag && !isglob(s))

      {

	/*

	 * 64-bit & 32-bit float load same speed on POWER,

	 * so don't differentiate, eg by adding sacle*2.0

	 */

	fno(s) += scale;

      }

      /* usage of tag stored in number of son of load_name (decl) */

      return zeroweights;

    }

  case ident_tag:

    {

      if (son(e)!= nilexp)

      {

	weights wdef;

	bool wdef_set;

	weights wbody;

	long noe = no(e) /* set by scan */ ;

#if 1

	if (isparam(e))

	{

	  /* initialising is a use */

	  fno(e) = scale;

	  wdef_set = 0;

	}

	else

#endif

	if (name(son(e)) == clear_tag || props(e) & defer_bit)

	{

	  fno(e) = 0.0;

	  wdef_set = 0;

	}

	else

	{

	  /*

	   * 64-bit & 32-bit float load same speed on POWER,

	   * so don't differentiate, eg by adding sacle*2.0

	   */

	  ASSERT(!isparam(e));

	  fno(e) = scale;

	  wdef = weightsv(scale, son(e));

	  wdef_set = 1;

	}

	/* weights for initialisation of dec */

	wbody = weightsv(scale, bro(son(e)));

	/* weights of body of scan */

	if (props(e) & defer_bit)

	{			/* declaration will be treated transparently

				 * in code production */

	  exp t = son(e);

	  exp s;

	  if (name(t) == val_tag || name(t) == real_tag)

	  {

	    return wbody;

	  }

	  while (name(t)!= name_tag)

	  {

	    t = son(t);

	  }

	  s = son(t);

	  if (name(s) == ident_tag && !isglob(t))

	  {

	    fno(s) += fno(e);

	  }

	  /* usage of tag stored in number of son of load_name (decl) */

	  return wbody;

	}			/* end deferred */

	if ((props(e) & inreg_bits) == 0 && fixregable(e))

	{

	  wp p;

	  /*

	   * Usage decreased by 1.5 because of dump and restore of s-reg.

	   * Dump and restore do not create load delay slots hence 1.5, not 2.0.

	   */

	  p = max_weights(fno(e) - 1.5 * scale, &wbody, 1);

	  no(e) = p.fix_break;

	  if (wdef_set)

	    return add_weights(&wdef, &p.wp_weights);

	  else

	    return p.wp_weights;

	}

	else if ((props(e) & infreg_bits) == 0 && floatregable(e))

	{

	  wp p;

	  /*

	   * Usage decreased by 1.5 because of dump and restore of double s-reg.

	   * 64-bit & 32-bit float load same speed on POWER, so don't differentiate.

	   * Dump and restore do not create load delay slots hence 1.5, not 2.0.

	   */

	  p = max_weights(fno(e) - 1.5 * scale, &wbody, 0);

	  no(e) = p.float_break;

	  if (wdef_set)

	    return add_weights(&wdef, &p.wp_weights);

	  else

	    return p.wp_weights;

	}

	else

	{

	  no(e) = noe /* restore to value given by scan */ ;

	  if (wdef_set)

	    return add_weights(&wdef, &wbody);

	  else

	    return wbody;

	}

      }

      else

      {

	return zeroweights;

      }

    }

  case rep_tag:

    {

      e = bro(son(e));

      goto tailrecurse;

    }

  case case_tag:

    {

      e = son(e);

      goto tailrecurse;

    }

  case labst_tag:

    {

      scale = fno(e);

      e = bro(son(e));

      goto tailrecurse;

    }

   case val_tag:

   case env_offset_tag:

   case general_env_offset_tag:

   case caller_name_tag:

    {

      return zeroweights;

    }

  case ncopies_tag:

    {

      scale = no(e)* scale;

      e = son(e);

      goto tailrecurse;

    }

  default:

    {

      if (son(e) == nilexp)

      {

	return zeroweights;

      }

      if (last(son(e)))

      {

	e = son(e);

	goto tailrecurse;

      }

      return(add_wlist(scale, son(e)));

    }

  }

}