void
peep(void)
{
Reg *r, *r1, *r2;
Prog *p, *p1;
int t;
/*
* complete R structure
*/
t = 0;
for(r=firstr; r!=R; r=r1) {
r1 = r->link;
if(r1 == R)
break;
p = r->prog->link;
while(p != r1->prog)
switch(p->as) {
default:
r2 = rega();
r->link = r2;
r2->link = r1;
r2->prog = p;
r2->p1 = r;
r->s1 = r2;
r2->s1 = r1;
r1->p1 = r2;
r = r2;
t++;
case ADATA:
case AGLOBL:
case ANAME:
case ASIGNAME:
p = p->link;
}
}
loop1:
t = 0;
for(r=firstr; r!=R; r=r->link) {
p = r->prog;
if(p->as == ASLL || p->as == ASRL || p->as == ASRA) {
/*
* elide shift into D_SHIFT operand of subsequent instruction
*/
if(shiftprop(r)) {
excise(r);
t++;
}
}
if(p->as == AMOVW || p->as == AMOVF || p->as == AMOVD)
if(regtyp(&p->to)) {
if(p->from.type == D_CONST)
constprop(&p->from, &p->to, r->s1);
else if(regtyp(&p->from))
if(p->from.type == p->to.type) {
if(copyprop(r)) {
excise(r);
t++;
} else
if(subprop(r) && copyprop(r)) {
excise(r);
t++;
}
}
}
}
if(t)
goto loop1;
/*
* look for MOVB x,R; MOVB R,R
*/
for(r=firstr; r!=R; r=r->link) {
p = r->prog;
switch(p->as) {
default:
continue;
case AEOR:
/*
* EOR -1,x,y => MVN x,y
*/
if(p->from.type == D_CONST && p->from.offset == -1) {
p->as = AMVN;
p->from.type = D_REG;
if(p->reg != NREG)
p->from.reg = p->reg;
else
p->from.reg = p->to.reg;
p->reg = NREG;
}
continue;
case AMOVH:
case AMOVHU:
case AMOVB:
case AMOVBU:
if(p->to.type != D_REG)
continue;
break;
}
r1 = r->link;
if(r1 == R)
continue;
p1 = r1->prog;
if(p1->as != p->as)
continue;
if(p1->from.type != D_REG || p1->from.reg != p->to.reg)
continue;
if(p1->to.type != D_REG || p1->to.reg != p->to.reg)
continue;
excise(r1);
}
for(r=firstr; r!=R; r=r->link) {
p = r->prog;
switch(p->as) {
case AMOVW:
case AMOVB:
case AMOVBU:
if(p->from.type == D_OREG && p->from.offset == 0)
xtramodes(r, &p->from);
else if(p->to.type == D_OREG && p->to.offset == 0)
xtramodes(r, &p->to);
else
continue;
break;
case ACMP:
/*
* elide CMP $0,x if calculation of x can set condition codes
*/
if(p->from.type != D_CONST || p->from.offset != 0)
continue;
r2 = r->s1;
if(r2 == R)
continue;
t = r2->prog->as;
switch(t) {
default:
continue;
case ABEQ:
case ABNE:
case ABMI:
case ABPL:
break;
case ABGE:
t = ABPL;
break;
case ABLT:
t = ABMI;
break;
case ABHI:
t = ABNE;
break;
case ABLS:
t = ABEQ;
break;
}
r1 = r;
do
r1 = uniqp(r1);
while (r1 != R && r1->prog->as == ANOP);
if(r1 == R)
continue;
p1 = r1->prog;
if(p1->to.type != D_REG)
continue;
if(p1->to.reg != p->reg)
if(!(p1->as == AMOVW && p1->from.type == D_REG && p1->from.reg == p->reg))
continue;
switch(p1->as) {
default:
continue;
case AMOVW:
if(p1->from.type != D_REG)
continue;
case AAND:
case AEOR:
case AORR:
case ABIC:
case AMVN:
case ASUB:
case ARSB:
case AADD:
case AADC:
case ASBC:
case ARSC:
break;
}
p1->scond |= C_SBIT;
r2->prog->as = t;
excise(r);
continue;
}
}
predicate();
}
void
peep(Prog *firstp)
{
Flow *r;
Graph *g;
Prog *p;
int t;
g = flowstart(firstp, sizeof(Flow));
if(g == nil)
return;
for(r=g->start, t=0; r!=nil; r=r->link, t++)
r->active = t;
loop1:
if(debug['P'] && debug['v'])
dumpit("loop1", g->start, 0);
t = 0;
for(r=g->start; r!=nil; r=r->link) {
p = r->prog;
switch(p->as) {
case ASLL:
case ASRL:
case ASRA:
/*
* elide shift into D_SHIFT operand of subsequent instruction
*/
// if(shiftprop(r)) {
// excise(r);
// t++;
// break;
// }
break;
case AMOVB:
case AMOVH:
case AMOVW:
case AMOVF:
case AMOVD:
if(regtyp(&p->from))
if(p->from.type == p->to.type)
if(p->scond == C_SCOND_NONE) {
if(copyprop(g, r)) {
excise(r);
t++;
break;
}
if(subprop(r) && copyprop(g, r)) {
excise(r);
t++;
break;
}
}
break;
case AMOVHS:
case AMOVHU:
case AMOVBS:
case AMOVBU:
if(p->from.type == D_REG) {
if(shortprop(r))
t++;
}
break;
#ifdef NOTDEF
if(p->scond == C_SCOND_NONE)
if(regtyp(&p->to))
if(isdconst(&p->from)) {
constprop(&p->from, &p->to, r->s1);
}
break;
#endif
}
}
if(t)
goto loop1;
for(r=g->start; r!=nil; r=r->link) {
p = r->prog;
switch(p->as) {
case AEOR:
/*
* EOR -1,x,y => MVN x,y
*/
if(isdconst(&p->from) && p->from.offset == -1) {
p->as = AMVN;
p->from.type = D_REG;
if(p->reg != NREG)
p->from.reg = p->reg;
else
p->from.reg = p->to.reg;
p->reg = NREG;
}
break;
}
}
for(r=g->start; r!=nil; r=r->link) {
p = r->prog;
switch(p->as) {
case AMOVW:
case AMOVB:
case AMOVBS:
case AMOVBU:
if(p->from.type == D_OREG && p->from.offset == 0)
xtramodes(g, r, &p->from);
else
if(p->to.type == D_OREG && p->to.offset == 0)
xtramodes(g, r, &p->to);
else
continue;
break;
// case ACMP:
// /*
// * elide CMP $0,x if calculation of x can set condition codes
// */
// if(isdconst(&p->from) || p->from.offset != 0)
// continue;
// r2 = r->s1;
// if(r2 == nil)
// continue;
// t = r2->prog->as;
// switch(t) {
// default:
// continue;
// case ABEQ:
// case ABNE:
// case ABMI:
// case ABPL:
// break;
// case ABGE:
// t = ABPL;
// break;
// case ABLT:
// t = ABMI;
// break;
// case ABHI:
// t = ABNE;
// break;
// case ABLS:
// t = ABEQ;
// break;
// }
// r1 = r;
// do
// r1 = uniqp(r1);
// while (r1 != nil && r1->prog->as == ANOP);
// if(r1 == nil)
// continue;
// p1 = r1->prog;
// if(p1->to.type != D_REG)
// continue;
// if(p1->to.reg != p->reg)
// if(!(p1->as == AMOVW && p1->from.type == D_REG && p1->from.reg == p->reg))
// continue;
//
// switch(p1->as) {
// default:
// continue;
// case AMOVW:
// if(p1->from.type != D_REG)
// continue;
// case AAND:
// case AEOR:
// case AORR:
// case ABIC:
// case AMVN:
// case ASUB:
// case ARSB:
// case AADD:
// case AADC:
// case ASBC:
// case ARSC:
// break;
// }
// p1->scond |= C_SBIT;
// r2->prog->as = t;
// excise(r);
// continue;
}
}
// predicate(g);
flowend(g);
}