C++ (Cpp) findpre Examples

Example #1

File: peep.c Project: cloudaice/golang

/*
 * shortprop eliminates redundant zero/sign extensions.
 *
 *   MOVBS x, R
 *   <no use R>
 *   MOVBS R, R'
 *
 * changed to
 *
 *   MOVBS x, R
 *   ...
 *   MOVB  R, R' (compiled to mov)
 *
 * MOVBS above can be a MOVBS, MOVBU, MOVHS or MOVHU.
 */
static int
shortprop(Flow *r)
{
	Prog *p, *p1;
	Flow *r1;

	p = r->prog;
	r1 = findpre(r, &p->from);
	if(r1 == nil)
		return 0;

	p1 = r1->prog;
	if(p1->as == p->as) {
		// Two consecutive extensions.
		goto gotit;
	}

	if(p1->as == AMOVW && isdconst(&p1->from)
	   && p1->from.offset >= 0 && p1->from.offset < 128) {
		// Loaded an immediate.
		goto gotit;
	}

	return 0;

gotit:
	if(debug['P'])
		print("shortprop\n%P\n%P", p1, p);
	switch(p->as) {
	case AMOVBS:
	case AMOVBU:
		p->as = AMOVB;
		break;
	case AMOVHS:
	case AMOVHU:
		p->as = AMOVH;
		break;
	}
	if(debug['P'])
		print(" => %A\n", p->as);
	return 1;
}

Example #2

File: peep.c Project: BGCX261/znos-git

int
xtramodes(Reg *r, Adr *a)
{
	Reg *r1, *r2, *r3;
	Prog *p, *p1;
	Adr v;

	p = r->prog;
	if(debug['h'] && p->as == AMOVB && p->from.type == D_OREG)	/* byte load */
		return 0;
	v = *a;
	v.type = D_REG;
	r1 = findpre(r, &v);
	if(r1 != R) {
		p1 = r1->prog;
		if(p1->to.type == D_REG && p1->to.reg == v.reg)
		switch(p1->as) {
		case AADD:
			if(p1->from.type == D_REG ||
			   (p1->from.type == D_SHIFT && (p1->from.offset&(1<<4)) == 0 &&
			    (p->as != AMOVB || (a == &p->from && (p1->from.offset&~0xf) == 0))) ||
			   (p1->from.type == D_CONST && 
			    p1->from.offset > -4096 && p1->from.offset < 4096))
			if(nochange(uniqs(r1), r, p1)) {
				if(a != &p->from || v.reg != p->to.reg)
				if (finduse(r->s1, &v)) {
					if(p1->reg == NREG || p1->reg == v.reg)
						/* pre-indexing */
						p->scond |= C_WBIT;
					else return 0;	
				}
				switch (p1->from.type) {
				case D_REG:
					/* register offset */
					a->type = D_SHIFT;
					a->offset = p1->from.reg;
					break;
				case D_SHIFT:
					/* scaled register offset */
					a->type = D_SHIFT;
				case D_CONST:
					/* immediate offset */
					a->offset = p1->from.offset;
					break;
				}
				if(p1->reg != NREG)
					a->reg = p1->reg;
				excise(r1);
				return 1;
			}
			break;
		case AMOVW:
			if(p1->from.type == D_REG)
			if((r2 = findinc(r1, r, &p1->from)) != R) {
			for(r3=uniqs(r2); r3->prog->as==ANOP; r3=uniqs(r3))
				;
			if(r3 == r) {
				/* post-indexing */
				p1 = r2->prog;
				a->reg = p1->to.reg;
				a->offset = p1->from.offset;
				p->scond |= C_PBIT;
				if(!finduse(r, &r1->prog->to))
					excise(r1);
				excise(r2);
				return 1;
			}
			}
			break;
		}
	}
	if(a != &p->from || a->reg != p->to.reg)
	if((r1 = findinc(r, R, &v)) != R) {
		/* post-indexing */
		p1 = r1->prog;
		a->offset = p1->from.offset;
		p->scond |= C_PBIT;
		excise(r1);
		return 1;
	}
	return 0;
}