/*
* the idea is to substitute
* one register for another
* from one MOV to another
* MOV a, R0
* ADD b, R0 / no use of R1
* MOV R0, R1
* would be converted to
* MOV a, R1
* ADD b, R1
* MOV R1, R0
* hopefully, then the former or latter MOV
* will be eliminated by copy propagation.
*/
int
subprop(Reg *r0)
{
Prog *p;
Addr *v1, *v2;
Reg *r;
int t;
p = r0->prog;
v1 = &p->from;
if(!regtyp(v1))
return 0;
v2 = &p->to;
if(!regtyp(v2))
return 0;
for(r=uniqp(r0); r!=R; r=uniqp(r)) {
if(uniqs(r) == R)
break;
p = r->prog;
switch(p->as) {
case ACALL:
return 0;
case AIMULL:
case AIMULW:
if(p->to.type != D_NONE)
break;
case ADIVB:
case ADIVL:
case ADIVW:
case AIDIVB:
case AIDIVL:
case AIDIVW:
case AIMULB:
case AMULB:
case AMULL:
case AMULW:
case AROLB:
case AROLL:
case AROLW:
case ARORB:
case ARORL:
case ARORW:
case ASALB:
case ASALL:
case ASALW:
case ASARB:
case ASARL:
case ASARW:
case ASHLB:
case ASHLL:
case ASHLW:
case ASHRB:
case ASHRL:
case ASHRW:
case AREP:
case AREPN:
case ACWD:
case ACDQ:
case ASTOSB:
case ASTOSL:
case AMOVSB:
case AMOVSL:
case AFSTSW:
return 0;
case AMOVL:
if(p->to.type == v1->type)
goto gotit;
break;
}
if(copyau(&p->from, v2) ||
copyau(&p->to, v2))
break;
if(copysub(&p->from, v1, v2, 0) ||
copysub(&p->to, v1, v2, 0))
break;
}
return 0;
gotit:
copysub(&p->to, v1, v2, 1);
if(debug['P']) {
print("gotit: %D->%D\n%P", v1, v2, r->prog);
if(p->from.type == v2->type)
print(" excise");
print("\n");
}
for(r=uniqs(r); r!=r0; r=uniqs(r)) {
p = r->prog;
copysub(&p->from, v1, v2, 1);
copysub(&p->to, v1, v2, 1);
if(debug['P'])
print("%P\n", r->prog);
}
t = v1->type;
v1->type = v2->type;
v2->type = t;
if(debug['P'])
print("%P last\n", r->prog);
return 1;
}
/*
* the idea is to substitute
* one register for another
* from one MOV to another
* MOV a, R0
* ADD b, R0 / no use of R1
* MOV R0, R1
* would be converted to
* MOV a, R1
* ADD b, R1
* MOV R1, R0
* hopefully, then the former or latter MOV
* will be eliminated by copy propagation.
*/
int
subprop(Reg *r0)
{
Prog *p;
Adr *v1, *v2;
Reg *r;
int t;
p = r0->prog;
v1 = &p->from;
if(!regtyp(v1))
return 0;
v2 = &p->to;
if(!regtyp(v2))
return 0;
for(r=uniqp(r0); r!=R; r=uniqp(r)) {
if(uniqs(r) == R)
break;
p = r->prog;
switch(p->as) {
case AJAL:
return 0;
case ASGT:
case ASGTU:
case AADD:
case AADDU:
case ASUB:
case ASUBU:
case ASLL:
case ASRL:
case ASRA:
case AOR:
case AAND:
case AXOR:
case AMUL:
case AMULU:
case ADIV:
case ADIVU:
case AADDD:
case AADDF:
case ASUBD:
case ASUBF:
case AMULD:
case AMULF:
case ADIVD:
case ADIVF:
if(p->to.type == v1->type)
if(p->to.reg == v1->reg) {
if(p->reg == NREG)
p->reg = p->to.reg;
goto gotit;
}
break;
case AMOVF:
case AMOVD:
case AMOVW:
if(p->to.type == v1->type)
if(p->to.reg == v1->reg)
goto gotit;
break;
}
if(copyau(&p->from, v2) ||
copyau1(p, v2) ||
copyau(&p->to, v2))
break;
if(copysub(&p->from, v1, v2, 0) ||
copysub1(p, v1, v2, 0) ||
copysub(&p->to, v1, v2, 0))
break;
}
return 0;
gotit:
copysub(&p->to, v1, v2, 1);
if(debug['P']) {
print("gotit: %D->%D\n%P", v1, v2, r->prog);
if(p->from.type == v2->type)
print(" excise");
print("\n");
}
for(r=uniqs(r); r!=r0; r=uniqs(r)) {
p = r->prog;
copysub(&p->from, v1, v2, 1);
copysub1(p, v1, v2, 1);
copysub(&p->to, v1, v2, 1);
if(debug['P'])
print("%P\n", r->prog);
}
t = v1->reg;
v1->reg = v2->reg;
v2->reg = t;
if(debug['P'])
print("%P last\n", r->prog);
return 1;
}
/*
* return
* 1 if v only used (and substitute),
* 2 if read-alter-rewrite
* 3 if set
* 4 if set and used
* 0 otherwise (not touched)
*/
int
copyu(Prog *p, Adr *v, Adr *s)
{
switch(p->as) {
default:
if(debug['P'])
print(" (?)");
return 2;
case ANOP: /* read, write */
case AMOVW:
case AMOVF:
case AMOVD:
case AMOVH:
case AMOVHU:
case AMOVB:
case AMOVBU:
case AMOVDW:
case AMOVWD:
case AMOVFD:
case AMOVDF:
if(s != A) {
if(copysub(&p->from, v, s, 1))
return 1;
if(!copyas(&p->to, v))
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyas(&p->to, v)) {
if(copyau(&p->from, v))
return 4;
return 3;
}
if(copyau(&p->from, v))
return 1;
if(copyau(&p->to, v))
return 1;
return 0;
case ASGT: /* read, read, write */
case ASGTU:
case AADD:
case AADDU:
case ASUB:
case ASUBU:
case ASLL:
case ASRL:
case ASRA:
case AOR:
case ANOR:
case AAND:
case AXOR:
case AMUL:
case AMULU:
case ADIV:
case ADIVU:
case AADDF:
case AADDD:
case ASUBF:
case ASUBD:
case AMULF:
case AMULD:
case ADIVF:
case ADIVD:
if(s != A) {
if(copysub(&p->from, v, s, 1))
return 1;
if(copysub1(p, v, s, 1))
return 1;
if(!copyas(&p->to, v))
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyas(&p->to, v)) {
if(p->reg == NREG)
p->reg = p->to.reg;
if(copyau(&p->from, v))
return 4;
if(copyau1(p, v))
return 4;
return 3;
}
if(copyau(&p->from, v))
return 1;
if(copyau1(p, v))
return 1;
if(copyau(&p->to, v))
return 1;
return 0;
case ABEQ: /* read, read */
case ABNE:
case ABGTZ:
case ABGEZ:
case ABLTZ:
case ABLEZ:
case ACMPEQD:
case ACMPEQF:
case ACMPGED:
case ACMPGEF:
case ACMPGTD:
case ACMPGTF:
case ABFPF:
case ABFPT:
if(s != A) {
if(copysub(&p->from, v, s, 1))
return 1;
return copysub1(p, v, s, 1);
}
if(copyau(&p->from, v))
return 1;
if(copyau1(p, v))
return 1;
return 0;
case AJMP: /* funny */
if(s != A) {
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyau(&p->to, v))
return 1;
return 0;
case ARET: /* funny */
if(v->type == D_REG)
if(v->reg == REGRET)
return 2;
if(v->type == D_FREG)
if(v->reg == FREGRET)
return 2;
case AJAL: /* funny */
if(v->type == D_REG) {
if(v->reg <= REGEXT && v->reg > exregoffset)
return 2;
if(REGARG && v->reg == REGARG)
return 2;
}
if(v->type == D_FREG)
if(v->reg <= FREGEXT && v->reg > exfregoffset)
return 2;
if(s != A) {
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyau(&p->to, v))
return 4;
return 3;
case ATEXT: /* funny */
if(v->type == D_REG)
if(v->reg == REGARG)
return 3;
return 0;
}
/* not reached */
}
/*
* return
* 1 if v only used (and substitute),
* 2 if read-alter-rewrite
* 3 if set
* 4 if set and used
* 0 otherwise (not touched)
*/
int
copyu(Prog *p, Adr *v, Adr *s)
{
switch(p->as) {
default:
if(debug['P'])
print("unknown op %A\n", p->as);
/* SBBL; ADCL; FLD1; SAHF */
return 2;
case ANEGB:
case ANEGW:
case ANEGL:
case ANOTB:
case ANOTW:
case ANOTL:
if(copyas(&p->to, v))
return 2;
break;
case ALEAL: /* lhs addr, rhs store */
if(copyas(&p->from, v))
return 2;
case ANOP: /* rhs store */
case AMOVL:
case AMOVBLSX:
case AMOVBLZX:
case AMOVWLSX:
case AMOVWLZX:
if(copyas(&p->to, v)) {
if(s != A)
return copysub(&p->from, v, s, 1);
if(copyau(&p->from, v))
return 4;
return 3;
}
goto caseread;
case ARCLB:
case ARCLL:
case ARCLW:
case ARCRB:
case ARCRL:
case ARCRW:
case AROLB:
case AROLL:
case AROLW:
case ARORB:
case ARORL:
case ARORW:
case ASALB:
case ASALL:
case ASALW:
case ASARB:
case ASARL:
case ASARW:
case ASHLB:
case ASHLL:
case ASHLW:
case ASHRB:
case ASHRL:
case ASHRW:
if(copyas(&p->to, v))
return 2;
if(copyas(&p->from, v))
if(p->from.type == D_CX)
return 2;
goto caseread;
case AADDB: /* rhs rar */
case AADDL:
case AADDW:
case AANDB:
case AANDL:
case AANDW:
case ADECL:
case ADECW:
case AINCL:
case AINCW:
case ASUBB:
case ASUBL:
case ASUBW:
case AORB:
case AORL:
case AORW:
case AXORB:
case AXORL:
case AXORW:
case AMOVB:
case AMOVW:
if(copyas(&p->to, v))
return 2;
goto caseread;
case ACMPL: /* read only */
case ACMPW:
case ACMPB:
caseread:
if(s != A) {
if(copysub(&p->from, v, s, 1))
return 1;
return copysub(&p->to, v, s, 1);
}
if(copyau(&p->from, v))
return 1;
if(copyau(&p->to, v))
return 1;
break;
case AJGE: /* no reference */
case AJNE:
case AJLE:
case AJEQ:
case AJHI:
case AJLS:
case AJMI:
case AJPL:
case AJGT:
case AJLT:
case AJCC:
case AJCS:
case AADJSP:
case AWAIT:
case ACLD:
break;
case AIMULL:
case AIMULW:
if(p->to.type != D_NONE) {
if(copyas(&p->to, v))
return 2;
goto caseread;
}
case ADIVB:
case ADIVL:
case ADIVW:
case AIDIVB:
case AIDIVL:
case AIDIVW:
case AIMULB:
case AMULB:
case AMULL:
case AMULW:
case ACWD:
case ACDQ:
if(v->type == D_AX || v->type == D_DX)
return 2;
goto caseread;
case AREP:
case AREPN:
if(v->type == D_CX)
return 2;
goto caseread;
case AMOVSB:
case AMOVSL:
if(v->type == D_DI || v->type == D_SI)
return 2;
goto caseread;
case ASTOSB:
case ASTOSL:
if(v->type == D_AX || v->type == D_DI)
return 2;
goto caseread;
case AJMP: /* funny */
if(s != A) {
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyau(&p->to, v))
return 1;
return 0;
case ARET: /* funny */
if(v->type == REGRET || v->type == FREGRET)
return 2;
if(s != A)
return 1;
return 3;
case ACALL: /* funny */
if(REGEXT && v->type <= REGEXT && v->type > exregoffset)
return 2;
if(REGARG >= 0 && v->type == (uchar)REGARG)
return 2;
if(s != A) {
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyau(&p->to, v))
return 4;
return 3;
case ATEXT: /* funny */
if(REGARG >= 0 && v->type == (uchar)REGARG)
return 3;
return 0;
}
return 0;
}
/*
* return
* 1 if v only used (and substitute),
* 2 if read-alter-rewrite
* 3 if set
* 4 if set and used
* 0 otherwise (not touched)
*/
int
copyu(Prog *p, Adr *v, Adr *s)
{
switch(p->as) {
default:
if(debug['P'])
print(" (???)");
return 2;
case AMOVM:
if(v->type != D_REG)
return 0;
if(p->from.type == D_CONST) { /* read reglist, read/rar */
if(s != A) {
if(p->from.offset&(1<<v->reg))
return 1;
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyau(&p->to, v)) {
if(p->scond&C_WBIT)
return 2;
return 1;
}
if(p->from.offset&(1<<v->reg))
return 1;
} else { /* read/rar, write reglist */
if(s != A) {
if(p->to.offset&(1<<v->reg))
return 1;
if(copysub(&p->from, v, s, 1))
return 1;
return 0;
}
if(copyau(&p->from, v)) {
if(p->scond&C_WBIT)
return 2;
if(p->to.offset&(1<<v->reg))
return 4;
return 1;
}
if(p->to.offset&(1<<v->reg))
return 3;
}
return 0;
case ANOP: /* read, write */
case AMOVW:
case AMOVF:
case AMOVD:
case AMOVH:
case AMOVHU:
case AMOVB:
case AMOVBU:
case AMOVDW:
case AMOVWD:
case AMOVFD:
case AMOVDF:
if(p->scond&(C_WBIT|C_PBIT))
if(v->type == D_REG) {
if(p->from.type == D_OREG || p->from.type == D_SHIFT) {
if(p->from.reg == v->reg)
return 2;
} else {
if(p->to.reg == v->reg)
return 2;
}
}
if(s != A) {
if(copysub(&p->from, v, s, 1))
return 1;
if(!copyas(&p->to, v))
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyas(&p->to, v)) {
if(copyau(&p->from, v))
return 4;
return 3;
}
if(copyau(&p->from, v))
return 1;
if(copyau(&p->to, v))
return 1;
return 0;
case AADD: /* read, read, write */
case ASUB:
case ARSB:
case ASLL:
case ASRL:
case ASRA:
case AORR:
case AAND:
case AEOR:
case AMUL:
case ADIV:
case ADIVU:
case AADDF:
case AADDD:
case ASUBF:
case ASUBD:
case AMULF:
case AMULD:
case ADIVF:
case ADIVD:
case ACMPF:
case ACMPD:
case ACMP:
case ACMN:
case ACASE:
if(s != A) {
if(copysub(&p->from, v, s, 1))
return 1;
if(copysub1(p, v, s, 1))
return 1;
if(!copyas(&p->to, v))
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyas(&p->to, v)) {
if(p->reg == NREG)
p->reg = p->to.reg;
if(copyau(&p->from, v))
return 4;
if(copyau1(p, v))
return 4;
return 3;
}
if(copyau(&p->from, v))
return 1;
if(copyau1(p, v))
return 1;
if(copyau(&p->to, v))
return 1;
return 0;
case ABEQ: /* read, read */
case ABNE:
case ABCS:
case ABHS:
case ABCC:
case ABLO:
case ABMI:
case ABPL:
case ABVS:
case ABVC:
case ABHI:
case ABLS:
case ABGE:
case ABLT:
case ABGT:
case ABLE:
if(s != A) {
if(copysub(&p->from, v, s, 1))
return 1;
return copysub1(p, v, s, 1);
}
if(copyau(&p->from, v))
return 1;
if(copyau1(p, v))
return 1;
return 0;
case AB: /* funny */
if(s != A) {
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyau(&p->to, v))
return 1;
return 0;
case ARET: /* funny */
if(v->type == D_REG)
if(v->reg == REGRET)
return 2;
if(v->type == D_FREG)
if(v->reg == FREGRET)
return 2;
case ABL: /* funny */
if(v->type == D_REG) {
if(v->reg <= REGEXT && v->reg > exregoffset)
return 2;
if(v->reg == (uchar)REGARG)
return 2;
}
if(v->type == D_FREG)
if(v->reg <= FREGEXT && v->reg > exfregoffset)
return 2;
if(s != A) {
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyau(&p->to, v))
return 4;
return 3;
case ATEXT: /* funny */
if(v->type == D_REG)
if(v->reg == (uchar)REGARG)
return 3;
return 0;
}
}
/*
* return
* 1 if v only used (and substitute),
* 2 if read-alter-rewrite
* 3 if set
* 4 if set and used
* 0 otherwise (not touched)
*/
int
copyu(Prog *p, Adr *v, Adr *s)
{
switch(p->as) {
default:
if(debug['P'])
print(" (?)");
return 2;
case ANOP: /* read, write */
case AMOVW:
case AMOVH:
case AMOVHU:
case AMOVB:
case AMOVBU:
case AFMOVF:
case AFMOVD:
case AFMOVDW:
case AFMOVWD:
case AFMOVFW:
case AFMOVWF:
case AFMOVFD:
case AFMOVDF:
if(s != A) {
if(copysub(&p->from, v, s, 1))
return 1;
if(!copyas(&p->to, v))
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyas(&p->to, v)) {
if(copyau(&p->from, v))
return 4;
return 3;
}
if(copyau(&p->from, v))
return 1;
if(copyau(&p->to, v))
return 1;
return 0;
case AADD: /* read read write */
case ASUB:
case ASLL:
case ASRL:
case ASRA:
case AOR:
case AAND:
case AXOR:
case AMUL:
case ADIV:
case ADIVL:
case AMOD:
case AMODL:
case AFADDF:
case AFADDD:
case AFSUBF:
case AFSUBD:
case AFMULF:
case AFMULD:
case AFDIVF:
case AFDIVD:
if(s != A) {
if(copysub(&p->from, v, s, 1))
return 1;
if(copysub1(p, v, s, 1))
return 1;
if(!copyas(&p->to, v))
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyas(&p->to, v)) {
if(p->reg == NREG)
p->reg = p->to.reg;
if(copyau(&p->from, v))
return 4;
if(copyau1(p, v))
return 4;
return 3;
}
if(copyau(&p->from, v))
return 1;
if(copyau1(p, v))
return 1;
if(copyau(&p->to, v))
return 1;
return 0;
case ABA: /* no reference */
case ABCC:
case ABCS:
case ABE:
case ABG:
case ABGE:
case ABGU:
case ABL:
case ABLE:
case ABLEU:
case ABN:
case ABNE:
case ABNEG:
case ABPOS:
case ABVC:
case ABVS:
case AFBA:
case AFBE:
case AFBG:
case AFBGE:
case AFBL:
case AFBLE:
case AFBNE:
case AFBN:
case AFBLG:
case AFBO:
case AFBU:
case AFBUE:
case AFBUG:
case AFBUGE:
case AFBUL:
case AFBULE:
break;
case ACMP: /* read read */
case AFCMPD:
case AFCMPF:
if(s != A) {
if(copysub(&p->from, v, s, 1))
return 1;
return copysub(&p->to, v, s, 1);
}
if(copyau(&p->from, v))
return 1;
if(copyau(&p->to, v))
return 1;
break;
case AJMP: /* funny */
if(s != A) {
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyau(&p->to, v))
return 1;
return 0;
case ARETURN: /* funny */
if(v->type == D_REG)
if(v->reg == REGRET)
return 2;
if(v->type == D_FREG)
if(v->reg == FREGRET)
return 2;
case AJMPL: /* funny */
if(v->type == D_REG) {
if(v->reg <= REGEXT && v->reg > exregoffset)
return 2;
if(v->reg == REGARG)
return 2;
}
if(v->type == D_FREG) {
if(v->reg <= FREGEXT && v->reg > exfregoffset)
return 2;
}
if(s != A) {
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyau(&p->to, v))
return 4;
return 3;
case ATEXT: /* funny */
if(v->type == D_REG)
if(v->reg == REGARG)
return 3;
return 0;
}
return 0;
}
/*
* return
* 1 if v only used (and substitute),
* 2 if read-alter-rewrite
* 3 if set
* 4 if set and used
* 0 otherwise (not touched)
*/
int
copyu(Prog *p, Adr *v, Adr *s)
{
ProgInfo info;
switch(p->as) {
case AJMP:
if(s != nil) {
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyau(&p->to, v))
return 1;
return 0;
case ARET:
if(s != nil)
return 1;
return 3;
case ACALL:
if(REGEXT && v->type <= REGEXT && v->type > exregoffset)
return 2;
if(REGARG >= 0 && v->type == (uchar)REGARG)
return 2;
if(v->type == p->from.type)
return 2;
if(s != nil) {
if(copysub(&p->to, v, s, 1))
return 1;
return 0;
}
if(copyau(&p->to, v))
return 4;
return 3;
case ATEXT:
if(REGARG >= 0 && v->type == (uchar)REGARG)
return 3;
return 0;
}
if(p->as == AVARDEF || p->as == AVARKILL)
return 0;
proginfo(&info, p);
if((info.reguse|info.regset) & RtoB(v->type))
return 2;
if(info.flags & LeftAddr)
if(copyas(&p->from, v))
return 2;
if((info.flags & (RightRead|RightWrite)) == (RightRead|RightWrite))
if(copyas(&p->to, v))
return 2;
if(info.flags & RightWrite) {
if(copyas(&p->to, v)) {
if(s != nil)
return copysub(&p->from, v, s, 1);
if(copyau(&p->from, v))
return 4;
return 3;
}
}
if(info.flags & (LeftAddr|LeftRead|LeftWrite|RightAddr|RightRead|RightWrite)) {
if(s != nil) {
if(copysub(&p->from, v, s, 1))
return 1;
return copysub(&p->to, v, s, 1);
}
if(copyau(&p->from, v))
return 1;
if(copyau(&p->to, v))
return 1;
}
return 0;
}
/*
* the idea is to substitute
* one register for another
* from one MOV to another
* MOV a, R0
* ADD b, R0 / no use of R1
* MOV R0, R1
* would be converted to
* MOV a, R1
* ADD b, R1
* MOV R1, R0
* hopefully, then the former or latter MOV
* will be eliminated by copy propagation.
*/
static int
subprop(Flow *r0)
{
Prog *p;
Adr *v1, *v2;
Flow *r;
int t;
ProgInfo info;
p = r0->prog;
v1 = &p->from;
if(!regtyp(v1))
return 0;
v2 = &p->to;
if(!regtyp(v2))
return 0;
for(r=uniqp(r0); r!=nil; r=uniqp(r)) {
if(debug['P'] && debug['v'])
print("\t? %P\n", r->prog);
if(uniqs(r) == nil)
break;
p = r->prog;
if(p->as == AVARDEF || p->as == AVARKILL)
continue;
proginfo(&info, p);
if(info.flags & Call)
return 0;
if(info.reguse | info.regset)
return 0;
if((info.flags & Move) && (info.flags & (SizeL|SizeQ|SizeF|SizeD)) && p->to.type == v1->type)
goto gotit;
if(copyau(&p->from, v2) || copyau(&p->to, v2))
break;
if(copysub(&p->from, v1, v2, 0) || copysub(&p->to, v1, v2, 0))
break;
}
return 0;
gotit:
copysub(&p->to, v1, v2, 1);
if(debug['P']) {
print("gotit: %D->%D\n%P", v1, v2, r->prog);
if(p->from.type == v2->type)
print(" excise");
print("\n");
}
for(r=uniqs(r); r!=r0; r=uniqs(r)) {
p = r->prog;
copysub(&p->from, v1, v2, 1);
copysub(&p->to, v1, v2, 1);
if(debug['P'])
print("%P\n", r->prog);
}
t = v1->type;
v1->type = v2->type;
v2->type = t;
if(debug['P'])
print("%P last\n", r->prog);
return 1;
}