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2 7u83 1 
/*
6 7u83 2 
 * Copyright (c) 2002-2005 The TenDRA Project <http://www.tendra.org/>.
3 
 * All rights reserved.
4 
 *
5 
 * Redistribution and use in source and binary forms, with or without
6 
 * modification, are permitted provided that the following conditions are met:
7 
 *
8 
 * 1. Redistributions of source code must retain the above copyright notice,
9 
 *    this list of conditions and the following disclaimer.
10 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
11 
 *    this list of conditions and the following disclaimer in the documentation
12 
 *    and/or other materials provided with the distribution.
13 
 * 3. Neither the name of The TenDRA Project nor the names of its contributors
14 
 *    may be used to endorse or promote products derived from this software
15 
 *    without specific, prior written permission.
16 
 *
17 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
18 
 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
19 
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20 
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
21 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
22 
 * EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
23 
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
24 
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25 
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
26 
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
27 
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 
 *
29 
 * $Id$
30 
 */
31 
/*
2 7u83 32 
    		 Crown Copyright (c) 1997
33 
 
34 
    This TenDRA(r) Computer Program is subject to Copyright
35 
    owned by the United Kingdom Secretary of State for Defence
36 
    acting through the Defence Evaluation and Research Agency
37 
    (DERA).  It is made available to Recipients with a
38 
    royalty-free licence for its use, reproduction, transfer
39 
    to other parties and amendment for any purpose not excluding
40 
    product development provided that any such use et cetera
41 
    shall be deemed to be acceptance of the following conditions:-
42 
 
43 
        (1) Its Recipients shall ensure that this Notice is
44 
        reproduced upon any copies or amended versions of it;
45 
 
46 
        (2) Any amended version of it shall be clearly marked to
47 
        show both the nature of and the organisation responsible
48 
        for the relevant amendment or amendments;
49 
 
50 
        (3) Its onward transfer from a recipient to another
51 
        party shall be deemed to be that party's acceptance of
52 
        these conditions;
53 
 
54 
        (4) DERA gives no warranty or assurance as to its
55 
        quality or suitability for any purpose and DERA accepts
56 
        no liability whatsoever in relation to any use to which
57 
        it may be put.
58 
*/
59 
 
60 
 
61 
/**********************************************************************
62 
$Author: release $
63 
$Date: 1998/01/17 15:56:06 $
64 
$Revision: 1.1.1.1 $
65 
$Log: regexps.c,v $
66 
 * Revision 1.1.1.1  1998/01/17  15:56:06  release
67 
 * First version to be checked into rolling release.
68 
 *
69 
 * Revision 1.7  1996/01/25  17:07:21  currie
70 
 * Alias with bit-fields
71 
 *
72 
 * Revision 1.6  1996/01/08  17:05:33  currie
73 
 * current_env in depends_on
74 
 *
75 
 * Revision 1.5  1995/10/20  10:48:03  currie
76 
 * avs -slow + attempts to cheat buggy scheduler
77 
 *
78 
 * Revision 1.4  1995/09/12  10:59:41  currie
79 
 * gcc pedanttry
80 
 *
81 
 * Revision 1.3  1995/09/04  10:11:57  currie
82 
 * e changes !
83 
 *
84 
 * Revision 1.2  1995/08/16  16:07:08  currie
85 
 * Shortened some .h names
86 
 *
87 
 * Revision 1.1  1995/04/13  09:08:06  currie
88 
 * Initial revision
89 
 *
90 
***********************************************************************/
91 
 
92 
/* regexps.c
93 
 
94 
For trivial 'peephole' optimisations
95 
 
96 
*/
97 
 
98 
 
99 
 
100 
#include "config.h"
101 
#include "expmacs.h"
102 
#include "addrtypes.h"
103 
#include "tags.h"
104 
#include "move.h"
105 
#include "bitsmacs.h"
106 
#include "maxminmacs.h"
107 
#include "shapemacs.h"
108 
#include "common_types.h"
109 
#include "extratags.h"
110 
#include "check.h"
111 
#include "basicread.h"
112 
#include "regexps.h"
113 
 
114 
regpeep regexps[48];		/* [0:31] fix pt - [32:47] floating pt */
115 
 
6 7u83 116 
bool sim_exp(exp a, exp b);
2 7u83 117 
 
118 
bool eq_sze
6 7u83 119 
(shape as, shape bs)
2 7u83 120 
{
6 7u83 121 
  if (is_floating(name(as))) return(name(as) ==name(bs));
2 7u83 122 
  if (is_floating(name(bs))) return 0;
6 7u83 123 
  return(shape_size(as) == shape_size(bs) && shape_align(as) ==shape_align(bs));
2 7u83 124 
}
125 
 
126 
bool sim_explist
6 7u83 127 
(exp al, exp bl)
2 7u83 128 
{
129 
  if (al == nilexp && bl == nilexp)
6 7u83 130 
    return(1);
2 7u83 131 
  if (al == nilexp || bl == nilexp)
6 7u83 132 
    return(0);
133 
  if (!sim_exp(al, bl))
134 
    return(0);
135 
  if (last(al) && last(bl))
136 
    return(1);
137 
  if (last(al) || last(bl))
138 
    return(0);
139 
  return(sim_explist(bro(al), bro(bl)));
2 7u83 140 
}
141 
 
142 
bool sim_exp
6 7u83 143 
(exp a, exp b)
2 7u83 144 
{	/* basically eq_exp except equal shapes
145 
				   requirement  is weakened to equal sizes
146 
				   and alignments */
6 7u83 147 
  if (name(a) == name(b)) {
148 
    if (name(a) == name_tag)
149 
      return(son(a) == son(b) && no(a) == no(b) &&
150 
	  eq_sze(sh(a), sh(b)));
151 
    if (name(a) ==maxlike_tag || name(a) ==minlike_tag || name(a) ==abslike_tag) {
152 
    	return(props(son(a)) ==props(son(b)) &&
153 
		shape_size(sh(a)) ==shape_size(sh(b)) &&
154 
    			sim_explist(son(son(a)),son(son(b))));
2 7u83 155 
    }
6 7u83 156 
    if (!is_a(name(a)) || !eq_sze(sh(a), sh(b)))
157 
      return(0);
2 7u83 158 
    if (name(a) == float_tag) return eq_exp(son(a), son(b));
6 7u83 159 
    return(no(a) == no(b) &&
160 
	sim_explist(son(a), son(b)));
2 7u83 161 
  };
6 7u83 162 
  return(0);
2 7u83 163 
}
164 
 
165 
void clear_all
6 7u83 166 
(void)
2 7u83 167 
{	/* forget all register - exp associations */
168 
  int   i;
169 
  for (i = 0; i < 48; i++) {
170 
    regexps[i].keptexp = nilexp;
6 7u83 171 
    setregalt(regexps[i].inans, 0);
2 7u83 172 
  }
173 
}
174 
 
175 
 
176 
void clear_reg
6 7u83 177 
(int i)
2 7u83 178 
{	/* forget reg i - exp association */
6 7u83 179 
  i = abs(i);
2 7u83 180 
  if (i >= 0 && i < 48) {
181 
    regexps[i].keptexp = nilexp;
6 7u83 182 
    setregalt(regexps[i].inans, 0);
2 7u83 183 
  }
184 
}
185 
 
186 
 
187 
ans iskept
6 7u83 188 
(exp e)
2 7u83 189 
{		/* find if e has already been evaluated
190 
				   into a register */
191 
  int   i;
192 
  ans nilans;
193 
  ans aa;
6 7u83 194 
  setregalt(nilans, 0);
2 7u83 195 
  aa = nilans;
196 
  for (i = 0; i < 48; i++) {
197 
    exp ke = regexps[i].keptexp;
198 
    bool isc = regexps[i].iscont;
199 
    if (ke != nilexp) {		/* there is an accociation with reg i */
200 
      if (
6 7u83 201 
	 ((!isc && sim_exp(ke, e)) ||
202 
	   (name(e) == cont_tag && isc  &&
203 
	      eq_sze(sh(ke), sh(e))
204 
	      && sim_exp(ke, son(e)) && al1(sh(son(e))) == al1(sh(ke)))
205 
	 )
2 7u83 206 
	) {
207 
	aa = (regexps[i].inans);
208 
	switch (aa.discrim) {
209 
	  case notinreg:
210 
	    {
211 
	      if (!aa.val.instoreans.adval) {
212 
				/* the expression is given indirectly - it
213 
				   may have also been loaded into a
214 
				   register */
215 
		continue;
216 
	      }
217 
	      /* else ... */
218 
	    }
219 
	  default:
220 
	    return aa;
221 
	}
222 
      }
223 
      else
6 7u83 224 
	if (name(ke) == cont_tag && !isc) {
2 7u83 225 
	  ans aq;
226 
	  aq = regexps[i].inans;
227 
	  if (aq.discrim == notinreg) {
228 
	    instore is;
6 7u83 229 
	    is = insalt(aq);
2 7u83 230 
	    if (!is.adval && is.b.offset == 0 && is.b.base > 0 && is.b.base < 31
6 7u83 231 
		&& sim_exp(son(ke), e)) {
2 7u83 232 
				/* the contents of req expression is here
233 
				   as a reg-offset */
234 
	      is.adval = 1;
6 7u83 235 
	      setinsalt(aq, is);
2 7u83 236 
	      return aq;
237 
	    }
238 
	  }
239 
	}
240 
	else
6 7u83 241 
	  if (name(ke) == reff_tag && !isc) {
2 7u83 242 
	    ans aq;
243 
	    aq = regexps[i].inans;
244 
	    if (aq.discrim == notinreg) {
245 
	      instore is;
6 7u83 246 
	      is = insalt(aq);
247 
	      if (is.adval && is.b.offset == (no(ke) / 8)
2 7u83 248 
		  && is.b.base > 0 && is.b.base < 31
6 7u83 249 
		  && sim_exp(son(ke), e)) {
2 7u83 250 
				/* a ref select of req expression is here
251 
				   as a reg-offset */
252 
		is.adval = 1;
253 
		is.b.offset = 0;
6 7u83 254 
		setinsalt(aq, is);
2 7u83 255 
		return aq;
256 
	      }
257 
	    }
258 
	  }
259 
    }
260 
  }
261 
  return aa;
262 
}
263 
 
264 
void keepexp
6 7u83 265 
(exp e, ans loc)
2 7u83 266 
{	/* set up exp - address association */
267 
  int   pos;
268 
  switch (loc.discrim) {
269 
    case insomereg:
270 
    case insomefreg: {
6 7u83 271 
	failer("Keep ? reg");
2 7u83 272 
      }
273 
    case inreg:
274 
      {
6 7u83 275 
	pos = regalt(loc);
2 7u83 276 
	break;
277 
      }
278 
    case infreg:
279 
      {
6 7u83 280 
	pos = fregalt(loc).fr + 32;
2 7u83 281 
	break;
282 
      }
283 
    case notinreg:
284 
      {
6 7u83 285 
	pos = insalt(loc).b.base;
2 7u83 286 
	if (pos < 0 || pos > 30)
287 
	  return;
288 
      }
289 
 
290 
  };
291 
  if (pos==2 || pos == 32) return;
292 
  regexps[pos].keptexp = e;
293 
  regexps[pos].inans = loc;
294 
  regexps[pos].iscont = 0;
295 
}
296 
 
297 
void keepcont
6 7u83 298 
(exp e, int reg)
2 7u83 299 
{/* set up cont(e)-reg association */
300 
  freg fr;
6 7u83 301 
  int   z = abs(reg);
2 7u83 302 
  if (z==2|| z==32) return;
303 
  if (z > 31) {
304 
    fr.dble = (reg < 0);
305 
    fr.fr = z - 32;
6 7u83 306 
    setfregalt(regexps[z].inans, fr);
2 7u83 307 
  }
308 
  else {
309 
    instore is;
310 
    is.b.base = reg;
311 
    is.b.offset = 0;
312 
    is.adval = 1;
6 7u83 313 
    setinsalt(regexps[z].inans, is);
2 7u83 314 
  }
315 
 
316 
  regexps[z].keptexp = e;
317 
 
318 
  regexps[z].iscont = 1;
319 
 
320 
}
321 
 
322 
void keepreg
6 7u83 323 
(exp e, int reg)
2 7u83 324 
{	/* set up e-reg association */
325 
  freg fr;
6 7u83 326 
  int   z = abs(reg);
2 7u83 327 
  if (z==2 || z==32) return;
328 
  if (z > 31) {
329 
    fr.dble = (reg < 0);
330 
    fr.fr = z - 32;
6 7u83 331 
    setfregalt(regexps[z].inans, fr);
2 7u83 332 
  }
333 
  else {
334 
    instore is;
335 
    is.b.base = reg;
336 
    is.b.offset = 0;
337 
    is.adval = 1;
6 7u83 338 
    setinsalt(regexps[z].inans, is);
2 7u83 339 
  }
340 
 
341 
  regexps[z].keptexp = e;
342 
  regexps[z].iscont = 0;
343 
}
344 
 
6 7u83 345 
static bool couldeffect(exp e, exp z, int count);
2 7u83 346 
 
347 
static bool couldbe
6 7u83 348 
(exp e, exp lhs, int count)
2 7u83 349 
{ /* could e be lhs? */
6 7u83 350 
  int   ne = name(e);
351 
  exp s = son(e);
2 7u83 352 
 
353 
  if (ne == name_tag) {
6 7u83 354 
    if (lhs != 0 && s == son(lhs)) {
2 7u83 355 
	return 1;
356 
    }
6 7u83 357 
    if (isvar(s)) {
358 
      return(lhs == 0 && (isvis(s) || isglob(s)));
2 7u83 359 
    }
6 7u83 360 
    if (name(s) == proc_tag)
361 
      return(lhs == 0);
362 
    if (son(s) == nilexp)
2 7u83 363 
      return 1;
364 
    if (count > 5) return 1; /* pathological */
6 7u83 365 
    return couldbe(son(s), lhs, count+1);
2 7u83 366 
  }
367 
  if (ne == cont_tag) {
6 7u83 368 
    if (lhs != 0 && name(s) == name_tag && son(s)!= nilexp) {
369 
      return(son(s) == son(lhs) || isvis(son(lhs)) || isvis(son(s)));
2 7u83 370 
    }
371 
    return 1;
372 
  }
373 
  if (ne == reff_tag || ne == field_tag) {
6 7u83 374 
    return couldbe(s, lhs, count);
2 7u83 375 
  }
376 
  if (ne == addptr_tag || ne == subptr_tag) {
6 7u83 377 
    return(couldbe(s, lhs, count) || couldeffect(bro(s), lhs, count));
2 7u83 378 
  }
379 
 
380 
  return 1;
381 
 
382 
}
383 
 
384 
static bool couldeffect
6 7u83 385 
(exp e, exp z, int count)
2 7u83 386 
{
387 
				/* could alteration to z effect e? */
6 7u83 388 
  int   ne = name(e);
2 7u83 389 
  if (ne == cont_tag) {
6 7u83 390 
    return couldbe(son(e), z, count);
2 7u83 391 
  }
392 
  if (ne == name_tag) {
6 7u83 393 
    if (isvar(son(e)))
394 
      return(z == 0 && isvis(son(e)));
395 
    if (name(son(e)) == proc_tag)
2 7u83 396 
      return 0;
6 7u83 397 
    if (son(son(e)) == nilexp)
2 7u83 398 
      return 1 /* could it happen? */ ;
399 
    if (count > 5) return 1; /* pathological */
6 7u83 400 
    return couldeffect(son(son(e)), z, count+1);
2 7u83 401 
 
402 
  }
403 
  if (ne < plus_tag || ne == contvol_tag)
404 
    return 1;
405 
 
6 7u83 406 
  e = son(e);
2 7u83 407 
 
408 
  while (e != nilexp) {
6 7u83 409 
    if (couldeffect(e, z, count))
2 7u83 410 
      return 1;
6 7u83 411 
    if (last(e))
2 7u83 412 
      return 0;
6 7u83 413 
    e = bro(e);
2 7u83 414 
  }
415 
  return 0;
416 
}
417 
 
418 
bool dependson
6 7u83 419 
(exp e, bool isc, exp z)
2 7u83 420 
{/* does e depend on z */
421 
  if (e == nilexp) {
422 
    return 0;
423 
  }
424 
  for (;;) {
6 7u83 425 
    if (name(z) == reff_tag || name(z) == addptr_tag ||
426 
	name(z) == subptr_tag) {
427 
      z = son(z);
2 7u83 428 
    }
429 
 
6 7u83 430 
   if (name(z)!= name_tag) {
431 
    if (name(z)!= cont_tag)
2 7u83 432 
      return 1;
433 
    z = 0;
434 
    break;
435 
   }
436 
 
6 7u83 437 
    if (isvar(son(z)))
2 7u83 438 
      break;
6 7u83 439 
    if (name(son(z)) == proc_tag) {
2 7u83 440 
      z = 0;
441 
      break;
442 
    }
6 7u83 443 
    if (son(son(z)) == nilexp)
2 7u83 444 
      return 1;			/* can it happen? */
6 7u83 445 
    z = son(son(z));
2 7u83 446 
  }
447 
 
448 
  /* z is now unambiguous variable name or 0 meaning some contents */
449 
 
6 7u83 450 
  return((isc)? couldbe(e, z, 0): couldeffect(e, z, 0));
2 7u83 451 
}
452 
 
453 
 
454 
 
455 
 
456 
 
457 
void clear_dep_reg
6 7u83 458 
(exp lhs)
2 7u83 459 
{	/* remove association of any register
460 
				   which depends on lhs */
461 
  int   i;
462 
  for (i = 0; i < 48; i++) {
6 7u83 463 
    if (dependson(regexps[i].keptexp, regexps[i].iscont, lhs)) {
2 7u83 464 
      regexps[i].keptexp = nilexp;
6 7u83 465 
      setregalt(regexps[i].inans, 0);
2 7u83 466 
    }
467 
  }
468 
}