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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.
*
* $Id$
*/
/*
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 15:56:06 $
$Revision: 1.1.1.1 $
$Log: regexps.c,v $
* Revision 1.1.1.1 1998/01/17 15:56:06 release
* First version to be checked into rolling release.
*
* Revision 1.7 1996/01/25 17:07:21 currie
* Alias with bit-fields
*
* Revision 1.6 1996/01/08 17:05:33 currie
* current_env in depends_on
*
* Revision 1.5 1995/10/20 10:48:03 currie
* avs -slow + attempts to cheat buggy scheduler
*
* Revision 1.4 1995/09/12 10:59:41 currie
* gcc pedanttry
*
* Revision 1.3 1995/09/04 10:11:57 currie
* e changes !
*
* Revision 1.2 1995/08/16 16:07:08 currie
* Shortened some .h names
*
* Revision 1.1 1995/04/13 09:08:06 currie
* Initial revision
*
***********************************************************************/
/* regexps.c
For trivial 'peephole' optimisations
*/
#include "config.h"
#include "expmacs.h"
#include "addrtypes.h"
#include "tags.h"
#include "move.h"
#include "bitsmacs.h"
#include "maxminmacs.h"
#include "shapemacs.h"
#include "common_types.h"
#include "extratags.h"
#include "check.h"
#include "basicread.h"
#include "regexps.h"
regpeep regexps[48]; /* [0:31] fix pt - [32:47] floating pt */
bool sim_exp(exp a, exp b);
bool eq_sze
(shape as, shape bs)
{
if (is_floating(name(as))) return(name(as) ==name(bs));
if (is_floating(name(bs))) return 0;
return(shape_size(as) == shape_size(bs) && shape_align(as) ==shape_align(bs));
}
bool sim_explist
(exp al, exp bl)
{
if (al == nilexp && bl == nilexp)
return(1);
if (al == nilexp || bl == nilexp)
return(0);
if (!sim_exp(al, bl))
return(0);
if (last(al) && last(bl))
return(1);
if (last(al) || last(bl))
return(0);
return(sim_explist(bro(al), bro(bl)));
}
bool sim_exp
(exp a, exp b)
{ /* basically eq_exp except equal shapes
requirement is weakened to equal sizes
and alignments */
if (name(a) == name(b)) {
if (name(a) == name_tag)
return(son(a) == son(b) && no(a) == no(b) &&
eq_sze(sh(a), sh(b)));
if (name(a) ==maxlike_tag || name(a) ==minlike_tag || name(a) ==abslike_tag) {
return(props(son(a)) ==props(son(b)) &&
shape_size(sh(a)) ==shape_size(sh(b)) &&
sim_explist(son(son(a)),son(son(b))));
}
if (!is_a(name(a)) || !eq_sze(sh(a), sh(b)))
return(0);
if (name(a) == float_tag) return eq_exp(son(a), son(b));
return(no(a) == no(b) &&
sim_explist(son(a), son(b)));
};
return(0);
}
void clear_all
(void)
{ /* forget all register - exp associations */
int i;
for (i = 0; i < 48; i++) {
regexps[i].keptexp = nilexp;
setregalt(regexps[i].inans, 0);
}
}
void clear_reg
(int i)
{ /* forget reg i - exp association */
i = abs(i);
if (i >= 0 && i < 48) {
regexps[i].keptexp = nilexp;
setregalt(regexps[i].inans, 0);
}
}
ans iskept
(exp e)
{ /* find if e has already been evaluated
into a register */
int i;
ans nilans;
ans aa;
setregalt(nilans, 0);
aa = nilans;
for (i = 0; i < 48; i++) {
exp ke = regexps[i].keptexp;
bool isc = regexps[i].iscont;
if (ke != nilexp) { /* there is an accociation with reg i */
if (
((!isc && sim_exp(ke, e)) ||
(name(e) == cont_tag && isc &&
eq_sze(sh(ke), sh(e))
&& sim_exp(ke, son(e)) && al1(sh(son(e))) == al1(sh(ke)))
)
) {
aa = (regexps[i].inans);
switch (aa.discrim) {
case notinreg:
{
if (!aa.val.instoreans.adval) {
/* the expression is given indirectly - it
may have also been loaded into a
register */
continue;
}
/* else ... */
}
default:
return aa;
}
}
else
if (name(ke) == cont_tag && !isc) {
ans aq;
aq = regexps[i].inans;
if (aq.discrim == notinreg) {
instore is;
is = insalt(aq);
if (!is.adval && is.b.offset == 0 && is.b.base > 0 && is.b.base < 31
&& sim_exp(son(ke), e)) {
/* the contents of req expression is here
as a reg-offset */
is.adval = 1;
setinsalt(aq, is);
return aq;
}
}
}
else
if (name(ke) == reff_tag && !isc) {
ans aq;
aq = regexps[i].inans;
if (aq.discrim == notinreg) {
instore is;
is = insalt(aq);
if (is.adval && is.b.offset == (no(ke) / 8)
&& is.b.base > 0 && is.b.base < 31
&& sim_exp(son(ke), e)) {
/* a ref select of req expression is here
as a reg-offset */
is.adval = 1;
is.b.offset = 0;
setinsalt(aq, is);
return aq;
}
}
}
}
}
return aa;
}
void keepexp
(exp e, ans loc)
{ /* set up exp - address association */
int pos;
switch (loc.discrim) {
case insomereg:
case insomefreg: {
failer("Keep ? reg");
}
case inreg:
{
pos = regalt(loc);
break;
}
case infreg:
{
pos = fregalt(loc).fr + 32;
break;
}
case notinreg:
{
pos = insalt(loc).b.base;
if (pos < 0 || pos > 30)
return;
}
};
if (pos==2 || pos == 32) return;
regexps[pos].keptexp = e;
regexps[pos].inans = loc;
regexps[pos].iscont = 0;
}
void keepcont
(exp e, int reg)
{/* set up cont(e)-reg association */
freg fr;
int z = abs(reg);
if (z==2|| z==32) return;
if (z > 31) {
fr.dble = (reg < 0);
fr.fr = z - 32;
setfregalt(regexps[z].inans, fr);
}
else {
instore is;
is.b.base = reg;
is.b.offset = 0;
is.adval = 1;
setinsalt(regexps[z].inans, is);
}
regexps[z].keptexp = e;
regexps[z].iscont = 1;
}
void keepreg
(exp e, int reg)
{ /* set up e-reg association */
freg fr;
int z = abs(reg);
if (z==2 || z==32) return;
if (z > 31) {
fr.dble = (reg < 0);
fr.fr = z - 32;
setfregalt(regexps[z].inans, fr);
}
else {
instore is;
is.b.base = reg;
is.b.offset = 0;
is.adval = 1;
setinsalt(regexps[z].inans, is);
}
regexps[z].keptexp = e;
regexps[z].iscont = 0;
}
static bool couldeffect(exp e, exp z, int count);
static bool couldbe
(exp e, exp lhs, int count)
{ /* could e be lhs? */
int ne = name(e);
exp s = son(e);
if (ne == name_tag) {
if (lhs != 0 && s == son(lhs)) {
return 1;
}
if (isvar(s)) {
return(lhs == 0 && (isvis(s) || isglob(s)));
}
if (name(s) == proc_tag)
return(lhs == 0);
if (son(s) == nilexp)
return 1;
if (count > 5) return 1; /* pathological */
return couldbe(son(s), lhs, count+1);
}
if (ne == cont_tag) {
if (lhs != 0 && name(s) == name_tag && son(s)!= nilexp) {
return(son(s) == son(lhs) || isvis(son(lhs)) || isvis(son(s)));
}
return 1;
}
if (ne == reff_tag || ne == field_tag) {
return couldbe(s, lhs, count);
}
if (ne == addptr_tag || ne == subptr_tag) {
return(couldbe(s, lhs, count) || couldeffect(bro(s), lhs, count));
}
return 1;
}
static bool couldeffect
(exp e, exp z, int count)
{
/* could alteration to z effect e? */
int ne = name(e);
if (ne == cont_tag) {
return couldbe(son(e), z, count);
}
if (ne == name_tag) {
if (isvar(son(e)))
return(z == 0 && isvis(son(e)));
if (name(son(e)) == proc_tag)
return 0;
if (son(son(e)) == nilexp)
return 1 /* could it happen? */ ;
if (count > 5) return 1; /* pathological */
return couldeffect(son(son(e)), z, count+1);
}
if (ne < plus_tag || ne == contvol_tag)
return 1;
e = son(e);
while (e != nilexp) {
if (couldeffect(e, z, count))
return 1;
if (last(e))
return 0;
e = bro(e);
}
return 0;
}
bool dependson
(exp e, bool isc, exp z)
{/* does e depend on z */
if (e == nilexp) {
return 0;
}
for (;;) {
if (name(z) == reff_tag || name(z) == addptr_tag ||
name(z) == subptr_tag) {
z = son(z);
}
if (name(z)!= name_tag) {
if (name(z)!= cont_tag)
return 1;
z = 0;
break;
}
if (isvar(son(z)))
break;
if (name(son(z)) == proc_tag) {
z = 0;
break;
}
if (son(son(z)) == nilexp)
return 1; /* can it happen? */
z = son(son(z));
}
/* z is now unambiguous variable name or 0 meaning some contents */
return((isc)? couldbe(e, z, 0): couldeffect(e, z, 0));
}
void clear_dep_reg
(exp lhs)
{ /* remove association of any register
which depends on lhs */
int i;
for (i = 0; i < 48; i++) {
if (dependson(regexps[i].keptexp, regexps[i].iscont, lhs)) {
regexps[i].keptexp = nilexp;
setregalt(regexps[i].inans, 0);
}
}
}