#include "gc.h" voidpeep(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 == 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);	}} voidexcise(Reg *r){	Prog *p; 	p = r->prog;	p->as = ANOP;	p->from = zprog.from;	p->to = zprog.to;	p->reg = zprog.reg; /**/} Reg*uniqp(Reg *r){	Reg *r1; 	r1 = r->p1;	if(r1 == R) {		r1 = r->p2;		if(r1 == R || r1->p2link != R)			return R;	} else		if(r->p2 != R)			return R;	return r1;} Reg*uniqs(Reg *r){	Reg *r1; 	r1 = r->s1;	if(r1 == R) {		r1 = r->s2;		if(r1 == R)			return R;	} else		if(r->s2 != R)			return R;	return r1;} intregtyp(Adr *a){ 	if(a->type == D_REG)		return 1;	if(a->type == D_FREG)		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. */intsubprop(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 ABL:		case ABX:			return 0; 		// case ACMP:		// case ACMN:		case AADD:		case ASUB:		// case ASLL:		// case ASRL:		// case ASRA:		// case AORR:		// case AAND:		// case AEOR:		// case AMUL:		// case ADIV:		// case ADIVU: 		// case ACMPF:		// case ACMPD:		// 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; 		case AMOVM:			t = 1<<v2->reg;			if((p->from.type == D_CONST && (p->from.offset&t)) ||			   (p->to.type == D_CONST && (p->to.offset&t)))				return 0;			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;} /* * The idea is to remove redundant copies. *	v1->v2	F=0 *	(use v2	s/v2/v1/)* *	set v1	F=1 *	use v2	return fail *	----------------- *	v1->v2	F=0 *	(use v2	s/v2/v1/)* *	set v1	F=1 *	set v2	return success */intcopyprop(Reg *r0){	Prog *p;	Adr *v1, *v2;	Reg *r; 	p = r0->prog;	v1 = &p->from;	v2 = &p->to;	if(copyas(v1, v2))		return 1;	for(r=firstr; r!=R; r=r->link)		r->active = 0;	return copy1(v1, v2, r0->s1, 0);} intcopy1(Adr *v1, Adr *v2, Reg *r, int f){	int t;	Prog *p; 	if(r->active) {		if(debug['P'])			print("act set; return 1\n");		return 1;	}	r->active = 1;	if(debug['P'])		print("copy %D->%D f=%d\n", v1, v2, f);	for(; r != R; r = r->s1) {		p = r->prog;		if(debug['P'])			print("%P", p);		if(!f && uniqp(r) == R) {			f = 1;			if(debug['P'])				print("; merge; f=%d", f);		}		t = copyu(p, v2, A);		switch(t) {		case 2:	/* rar, cant split */			if(debug['P'])				print("; %Drar; return 0\n", v2);			return 0; 		case 3:	/* set */			if(debug['P'])				print("; %Dset; return 1\n", v2);			return 1; 		case 1:	/* used, substitute */		case 4:	/* use and set */			if(f) {				if(!debug['P'])					return 0;				if(t == 4)					print("; %Dused+set and f=%d; return 0\n", v2, f);				else					print("; %Dused and f=%d; return 0\n", v2, f);				return 0;			}			if(copyu(p, v2, v1)) {				if(debug['P'])					print("; sub fail; return 0\n");				return 0;			}			if(debug['P'])				print("; sub%D/%D", v2, v1);			if(t == 4) {				if(debug['P'])					print("; %Dused+set; return 1\n", v2);				return 1;			}			break;		}		if(!f) {			t = copyu(p, v1, A);			if(!f && (t == 2 || t == 3 || t == 4)) {				f = 1;				if(debug['P'])					print("; %Dset and !f; f=%d", v1, f);			}		}		if(debug['P'])			print("\n");		if(r->s2)			if(!copy1(v1, v2, r->s2, f))				return 0;	}	return 1;} /* * The idea is to remove redundant constants. *	$c1->v1 *	($c1->v2 s/$c1/v1)* *	set v1  return * The v1->v2 should be eliminated by copy propagation. */voidconstprop(Adr *c1, Adr *v1, Reg *r){	Prog *p; 	if(debug['C'])		print("constprop %D->%D\n", c1, v1);	for(; r != R; r = r->s1) {		p = r->prog;		if(debug['C'])			print("%P", p);		if(uniqp(r) == R) {			if(debug['C'])				print("; merge; return\n");			return;		}		if(p->as == AMOVW && copyas(&p->from, c1)) {				if(debug['C'])					print("; sub%D/%D", &p->from, v1);				p->from = *v1;		} else if(copyu(p, v1, A) > 1) {			if(debug['C'])				print("; %Dset; return\n", v1);			return;		}		if(debug['C'])			print("\n");		if(r->s2)			constprop(c1, v1, r->s2);	}} /* * 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) */intcopyu(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))					diag(Z, "movm dst being replaced");	// was return 1;				return 0;			}			if(copyau(&p->to, v))				return 2;		// register updated in thumb // was 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))					diag(Z, "movm src being replaced");	// was return 1;				return 0;			}			if(copyau(&p->from, v)) {				// if(p->to.offset&(1<<v->reg))					// return 4;				return 2;		// register updated in thumb // was 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(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;		}

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