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/*
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.
*/
/*
$Log: regexps.c,v $
* Revision 1.1.1.1 1998/01/17 15:56:03 release
* First version to be checked into rolling release.
*
* Revision 1.4 1996/11/14 15:22:26 wfs
* Fixed a bug in regexps.c which was common to most of the installers and
* has only just come to light due to PWE's work on powertrans. (There was
* previously only a patch.) Cosmetic changes to other files.
*
* Revision 1.3 1996/01/23 15:26:07 wfs
* "current_env_tag" in "dependson()".
*
* Revision 1.2 1995/12/18 13:12:30 wfs
* Put hppatrans uder cvs control. Major Changes made since last release
* include:
* (i) PIC code generation.
* (ii) Profiling.
* (iii) Dynamic Initialization.
* (iv) Debugging of Exception Handling and Diagnostics.
*
* Revision 5.2 1995/10/20 14:11:15 wfs
* gcc compilation changes.
*
* Revision 5.1 1995/09/15 13:13:36 wfs
* Mike Gerrard's bug fix incorporated.
*
* Revision 5.0 1995/08/25 13:42:58 wfs
* Preperation for August 25 Glue release
*
* Revision 3.4 1995/08/25 10:29:56 wfs
* Register synonyms changed
*
* Revision 3.4 1995/08/25 10:29:56 wfs
* Register synonyms changed
*
* Revision 3.1 95/04/10 16:28:04 16:28:04 wfs (William Simmonds)
* Apr95 tape version.
*
* Revision 3.0 95/03/30 11:18:54 11:18:54 wfs (William Simmonds)
* Mar95 tape version with CRCR95_178 bug fix.
*
* Revision 2.0 95/03/15 15:28:43 15:28:43 wfs (William Simmonds)
* spec 3.1 changes implemented, tests outstanding.
*
* Revision 1.1 95/01/11 13:16:12 13:16:12 wfs (William Simmonds)
* Initial revision
*
*/
#define HPPATRANS_CODE
/* 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 "regmacs.h"
#include "myassert.h"
#include "comment.h"
#include "check.h"
#include "regexps.h"
/* 22.11.94. Corrected bug found by Ian Currie, i.e. isglob(s) assertion
added to line 351 */
int line;
regpeep regexps[64]; /* [0:31] fix pt - [32:47] floating pt */
bool sim_exp PROTO_S ( ( exp, exp ) ) ;
/* Same size and alignment and "both float or both fixed". */
bool eq_sze
PROTO_N ( ( as, bs ) )
PROTO_T ( shape as X 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
PROTO_N ( ( al, bl ) )
PROTO_T ( exp al X 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
PROTO_N ( ( a, b ) )
PROTO_T ( exp a X 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 (!is_a(name(a)) || !eq_sze(sh(a), sh(b)))
return (0);
if(name(a)==float_tag)/* NEW bit */
{
return eq_exp(son(a),son(b));
}
return (no(a) == no(b) && sim_explist(son(a), son(b)));
};
return (0);
}
/* forget all register - exp associations */
void clear_all
PROTO_Z ()
{
int i;
for (i = 0; i < 48; i++)
{
regexps[i].keptexp = nilexp;
setregalt(regexps[i].inans, 0);
}
}
/* forget reg i - exp association */
void clear_reg
PROTO_N ( ( i ) )
PROTO_T ( int i )
{
i = ABS_OF(i);
if (i >= 0 && i < 48)
{
regexps[i].keptexp = nilexp;
setregalt(regexps[i].inans, 0);
}
}
/* find if e has already been evaluated into a register */
ans iskept
PROTO_N ( ( e ) )
PROTO_T ( exp e )
{
int i;
ans nilans;
setregalt(nilans, 0); /* init nilans */
#ifdef NO_KEPT_OPTS
/* no reg tracking */
return nilans;
#endif
/* reg tracking of unions unsafe, as views of location can differ */
/* +++ track on fields */
/* +++ safe to allow structs but not unions */
if (name(sh(e)) == cpdhd)
{
return 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)))
)
)
{
ans aa ;
aa = (regexps[i].inans);
#if 0
FULLCOMMENT4("iskept found: reg=%d isc=%d name(e)=%d name(son(e))=%d", i, isc, name(e), name(son(e)));
FULLCOMMENT3(" hd(e)=%d hd(son(e))=%d hd(ke)=%d", name(sh(e)), name(sh(son(e))), name(sh(ke)));
FULLCOMMENT3(" sim_exp(ke, e)=%d sim_exp(ke, son(e))=%d eq_size(sh(ke), sh(e))=%d",
sim_exp(ke, e), sim_exp(ke, son(e)), eq_size(sh(ke), sh(e)));
#endif
switch (discrim ( aa ))
{
case notinreg:
{
if (!aa.val.instoreans.adval)
{
/*
* the expression is given indirectly - it may have also been
* loaded into a register
*/
continue;
}
}
/* FALLTHROUGH */
default:
return aa;
}
}
else if (name(ke) == cont_tag && !isc)
{
ans aq;
aq = regexps[i].inans;
if (discrim ( aq ) == notinreg)
{
instore is;
is = insalt(aq);
if (!is.adval && is.b.offset == 0 && IS_FIXREG(is.b.base)
&& 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 (discrim ( aq ) == notinreg)
{
instore is;
is = insalt(aq);
if (is.adval && is.b.offset == (no(ke) / 8)
&& IS_FIXREG(is.b.base)
&& 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 nilans;
}
/* set up exp - address association */
void keepexp
PROTO_N ( ( e, loc ) )
PROTO_T ( exp e X ans loc )
{
int reg=0;
switch (discrim ( loc ))
{
case insomereg:
case insomefreg:
{
fail("keep ? reg");
}
#if USE_BITAD
case bitad:
{
return;
}
#endif
case inreg:
{
reg = regalt(loc);
break;
}
case infreg:
{
reg = fregalt(loc).fr + 32;
break;
}
case notinreg:
{
reg = insalt(loc).b.base;
if (!IS_FIXREG(reg))
return;
break;
}
default:{}
}
assert(reg >= 0 && reg < 48);
assert(reg != GR1);
regexps[reg].keptexp = e;
regexps[reg].inans = loc;
regexps[reg].iscont = 0;
}
/* set up cont(e)-reg association */
void keepcont
PROTO_N ( ( e, regcode ) )
PROTO_T ( exp e X int regcode )
{
freg fr;
int reg = ABS_OF(regcode);
assert(reg >= 0 && reg < 48);
assert(reg != GR1);
if (reg > 31)
{
fr.dble = ((regcode < 0) ? 1 : 0);
fr.fr = reg - 32;
setfregalt(regexps[reg].inans, fr);
}
else
{
instore is;
is.b.base = regcode;
is.b.offset = 0;
is.adval = 1;
setinsalt(regexps[reg].inans, is);
}
regexps[reg].keptexp = e;
regexps[reg].iscont = 1;
}
/* set up e-reg association */
void keepreg
PROTO_N ( ( e, regcode ) )
PROTO_T ( exp e X int regcode )
{
freg fr;
int reg = ABS_OF(regcode);
assert(reg >= 0 && reg < 48);
assert(reg != GR1);
if (reg > 31)
{
fr.dble = ((regcode < 0) ? 1 : 0);
fr.fr = reg - 32;
setfregalt(regexps[reg].inans, fr);
}
else
{
instore is;
is.b.base = regcode;
is.b.offset = 0;
is.adval = 1;
setinsalt(regexps[reg].inans, is);
}
regexps[reg].keptexp = e;
regexps[reg].iscont = 0;
}
bool couldeffect PROTO_S ( ( exp, exp ) ) ;
/* could e be lhs */
bool couldbe
PROTO_N ( ( e, lhs ) )
PROTO_T ( exp e X exp 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 (IS_A_PROC(s))
return (lhs == 0);
if (son(s) == nilexp)
return 1;
return couldbe(son(s), lhs);
}
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);
}
if (ne == addptr_tag || ne == subptr_tag)
{
return (couldbe(s, lhs) || couldeffect(bro(s), lhs));
}
return 1;
}
/* could alteration to z effect e? */
bool couldeffect
PROTO_N ( ( e, z /* a name or zero */ ) )
PROTO_T ( exp e X exp z /* a name or zero */ )
{
int ne = name(e);
if (ne == cont_tag)
{
return couldbe(son(e), z);
}
if (ne == name_tag)
{
if (isvar(son(e)))
return (z == 0 && isvis(son(e)));
if ( IS_A_PROC(son(e)) )
return 0;
if (son(son(e)) == nilexp)
return 1 /* could it happen? */ ;
return couldeffect(son(son(e)), z);
}
if (ne < plus_tag || ne == contvol_tag)
return 1;
e = son(e);
while (e != nilexp)
{
if (couldeffect(e, z))
return 1;
if (last(e))
return 0;
e = bro(e);
}
return 0;
}
bool dependson
PROTO_N ( ( e, isc, z ) )
PROTO_T ( exp e X bool isc X 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 ( IS_A_PROC(son(z)) )
{
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) : couldeffect(e, z));
}
/* remove association of any register which depends on lhs */
void clear_dep_reg
PROTO_N ( ( lhs ) )
PROTO_T ( exp 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);
}
}
}