root/src/cmd/5c/reg.c

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DEFINITIONS

This source file includes following definitions.
  1. rega
  2. rcmp
  3. regopt
  4. addsplits
  5. addmove
  6. mkvar
  7. prop
  8. postorder
  9. rpolca
  10. doms
  11. loophead
  12. loopmark
  13. loopit
  14. synch
  15. allreg
  16. paint1
  17. paint2
  18. paint3
  19. addreg
  20. RtoB
  21. BtoR
  22. FtoB
  23. BtoF

// Inferno utils/5c/reg.c
// http://code.google.com/p/inferno-os/source/browse/utils/5c/reg.c
//
//      Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
//      Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
//      Portions Copyright © 1997-1999 Vita Nuova Limited
//      Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
//      Portions Copyright © 2004,2006 Bruce Ellis
//      Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
//      Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
//      Portions Copyright © 2009 The Go Authors.  All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.


#include "gc.h"

void    addsplits(void);

Reg*
rega(void)
{
        Reg *r;

        r = freer;
        if(r == R) {
                r = alloc(sizeof(*r));
        } else
                freer = r->link;

        *r = zreg;
        return r;
}

int
rcmp(const void *a1, const void *a2)
{
        Rgn *p1, *p2;
        int c1, c2;

        p1 = (Rgn*)a1;
        p2 = (Rgn*)a2;
        c1 = p2->cost;
        c2 = p1->cost;
        if(c1 -= c2)
                return c1;
        return p2->varno - p1->varno;
}

void
regopt(Prog *p)
{
        Reg *r, *r1, *r2;
        Prog *p1;
        int i, z;
        int32 initpc, val, npc;
        uint32 vreg;
        Bits bit;
        struct
        {
                int32   m;
                int32   c;
                Reg*    p;
        } log5[6], *lp;

        firstr = R;
        lastr = R;
        nvar = 0;
        regbits = 0;
        for(z=0; z<BITS; z++) {
                externs.b[z] = 0;
                params.b[z] = 0;
                consts.b[z] = 0;
                addrs.b[z] = 0;
        }

        /*
         * pass 1
         * build aux data structure
         * allocate pcs
         * find use and set of variables
         */
        val = 5L * 5L * 5L * 5L * 5L;
        lp = log5;
        for(i=0; i<5; i++) {
                lp->m = val;
                lp->c = 0;
                lp->p = R;
                val /= 5L;
                lp++;
        }
        val = 0;
        for(; p != P; p = p->link) {
                switch(p->as) {
                case ADATA:
                case AGLOBL:
                case ANAME:
                case ASIGNAME:
                case AFUNCDATA:
                        continue;
                }
                r = rega();
                if(firstr == R) {
                        firstr = r;
                        lastr = r;
                } else {
                        lastr->link = r;
                        r->p1 = lastr;
                        lastr->s1 = r;
                        lastr = r;
                }
                r->prog = p;
                r->pc = val;
                val++;

                lp = log5;
                for(i=0; i<5; i++) {
                        lp->c--;
                        if(lp->c <= 0) {
                                lp->c = lp->m;
                                if(lp->p != R)
                                        lp->p->log5 = r;
                                lp->p = r;
                                (lp+1)->c = 0;
                                break;
                        }
                        lp++;
                }

                r1 = r->p1;
                if(r1 != R)
                switch(r1->prog->as) {
                case ARET:
                case AB:
                case ARFE:
                        r->p1 = R;
                        r1->s1 = R;
                }

                /*
                 * left side always read
                 */
                bit = mkvar(&p->from, p->as==AMOVW);
                for(z=0; z<BITS; z++)
                        r->use1.b[z] |= bit.b[z];

                /*
                 * right side depends on opcode
                 */
                bit = mkvar(&p->to, 0);
                if(bany(&bit))
                switch(p->as) {
                default:
                        diag(Z, "reg: unknown asop: %A", p->as);
                        break;

                /*
                 * right side write
                 */
                case ANOP:
                case AMOVB:
                case AMOVBS:
                case AMOVBU:
                case AMOVH:
                case AMOVHS:
                case AMOVHU:
                case AMOVW:
                case AMOVF:
                case AMOVD:
                        for(z=0; z<BITS; z++)
                                r->set.b[z] |= bit.b[z];
                        break;

                /*
                 * right side read
                 */
                case APLD:
                        for(z=0; z<BITS; z++)
                                r->use2.b[z] |= bit.b[z];
                        break;

                /*
                 * funny
                 */
                case ABL:
                        for(z=0; z<BITS; z++)
                                addrs.b[z] |= bit.b[z];
                        break;
                }

                if(p->as == AMOVM) {
                        if(p->from.type == D_CONST)
                                z = p->from.offset;
                        else
                                z = p->to.offset;
                        for(i=0; z; i++) {
                                if(z&1)
                                        regbits |= RtoB(i);
                                z >>= 1;
                        }
                }
        }
        if(firstr == R)
                return;
        initpc = pc - val;
        npc = val;

        /*
         * pass 2
         * turn branch references to pointers
         * build back pointers
         */
        for(r = firstr; r != R; r = r->link) {
                p = r->prog;
                if(p->to.type == D_BRANCH) {
                        val = p->to.offset - initpc;
                        r1 = firstr;
                        while(r1 != R) {
                                r2 = r1->log5;
                                if(r2 != R && val >= r2->pc) {
                                        r1 = r2;
                                        continue;
                                }
                                if(r1->pc == val)
                                        break;
                                r1 = r1->link;
                        }
                        if(r1 == R) {
                                nearln = p->lineno;
                                diag(Z, "ref not found\n%P", p);
                                continue;
                        }
                        if(r1 == r) {
                                nearln = p->lineno;
                                diag(Z, "ref to self\n%P", p);
                                continue;
                        }
                        r->s2 = r1;
                        r->p2link = r1->p2;
                        r1->p2 = r;
                }
        }
        if(debug['R']) {
                p = firstr->prog;
                print("\n%L %D\n", p->lineno, &p->from);
        }

        /*
         * pass 2.5
         * find looping structure
         */
        for(r = firstr; r != R; r = r->link)
                r->active = 0;
        change = 0;
        loopit(firstr, npc);

        /*
         * pass 3
         * iterate propagating usage
         *      back until flow graph is complete
         */
loop1:
        change = 0;
        for(r = firstr; r != R; r = r->link)
                r->active = 0;
        for(r = firstr; r != R; r = r->link)
                if(r->prog->as == ARET)
                        prop(r, zbits, zbits);
loop11:
        /* pick up unreachable code */
        i = 0;
        for(r = firstr; r != R; r = r1) {
                r1 = r->link;
                if(r1 && r1->active && !r->active) {
                        prop(r, zbits, zbits);
                        i = 1;
                }
        }
        if(i)
                goto loop11;
        if(change)
                goto loop1;


        /*
         * pass 4
         * iterate propagating register/variable synchrony
         *      forward until graph is complete
         */
loop2:
        change = 0;
        for(r = firstr; r != R; r = r->link)
                r->active = 0;
        synch(firstr, zbits);
        if(change)
                goto loop2;

        addsplits();

        if(debug['R'] && debug['v']) {
                print("\nprop structure:\n");
                for(r = firstr; r != R; r = r->link) {
                        print("%d:%P", r->loop, r->prog);
                        for(z=0; z<BITS; z++)
                                bit.b[z] = r->set.b[z] |
                                        r->refahead.b[z] | r->calahead.b[z] |
                                        r->refbehind.b[z] | r->calbehind.b[z] |
                                        r->use1.b[z] | r->use2.b[z];
                        if(bany(&bit)) {
                                print("\t");
                                if(bany(&r->use1))
                                        print(" u1=%B", r->use1);
                                if(bany(&r->use2))
                                        print(" u2=%B", r->use2);
                                if(bany(&r->set))
                                        print(" st=%B", r->set);
                                if(bany(&r->refahead))
                                        print(" ra=%B", r->refahead);
                                if(bany(&r->calahead))
                                        print(" ca=%B", r->calahead);
                                if(bany(&r->refbehind))
                                        print(" rb=%B", r->refbehind);
                                if(bany(&r->calbehind))
                                        print(" cb=%B", r->calbehind);
                        }
                        print("\n");
                }
        }

        /*
         * pass 5
         * isolate regions
         * calculate costs (paint1)
         */
        r = firstr;
        if(r) {
                for(z=0; z<BITS; z++)
                        bit.b[z] = (r->refahead.b[z] | r->calahead.b[z]) &
                          ~(externs.b[z] | params.b[z] | addrs.b[z] | consts.b[z]);
                if(bany(&bit)) {
                        nearln = r->prog->lineno;
                        warn(Z, "used and not set: %B", bit);
                        if(debug['R'] && !debug['w'])
                                print("used and not set: %B\n", bit);
                }
        }

        for(r = firstr; r != R; r = r->link)
                r->act = zbits;
        rgp = region;
        nregion = 0;
        for(r = firstr; r != R; r = r->link) {
                for(z=0; z<BITS; z++)
                        bit.b[z] = r->set.b[z] &
                          ~(r->refahead.b[z] | r->calahead.b[z] | addrs.b[z]);
                if(bany(&bit)) {
                        nearln = r->prog->lineno;
                        warn(Z, "set and not used: %B", bit);
                        if(debug['R'])
                                print("set and not used: %B\n", bit);
                        excise(r);
                }
                for(z=0; z<BITS; z++)
                        bit.b[z] = LOAD(r) & ~(r->act.b[z] | addrs.b[z]);
                while(bany(&bit)) {
                        i = bnum(bit);
                        rgp->enter = r;
                        rgp->varno = i;
                        change = 0;
                        if(debug['R'] && debug['v'])
                                print("\n");
                        paint1(r, i);
                        bit.b[i/32] &= ~(1L<<(i%32));
                        if(change <= 0) {
                                if(debug['R'])
                                        print("%L $%d: %B\n",
                                                r->prog->lineno, change, blsh(i));
                                continue;
                        }
                        rgp->cost = change;
                        nregion++;
                        if(nregion >= NRGN) {
                                warn(Z, "too many regions");
                                goto brk;
                        }
                        rgp++;
                }
        }
brk:
        qsort(region, nregion, sizeof(region[0]), rcmp);

        /*
         * pass 6
         * determine used registers (paint2)
         * replace code (paint3)
         */
        rgp = region;
        for(i=0; i<nregion; i++) {
                bit = blsh(rgp->varno);
                vreg = paint2(rgp->enter, rgp->varno);
                vreg = allreg(vreg, rgp);
                if(debug['R']) {
                        if(rgp->regno >= NREG)
                                print("%L $%d F%d: %B\n",
                                        rgp->enter->prog->lineno,
                                        rgp->cost,
                                        rgp->regno-NREG,
                                        bit);
                        else
                                print("%L $%d R%d: %B\n",
                                        rgp->enter->prog->lineno,
                                        rgp->cost,
                                        rgp->regno,
                                        bit);
                }
                if(rgp->regno != 0)
                        paint3(rgp->enter, rgp->varno, vreg, rgp->regno);
                rgp++;
        }
        /*
         * pass 7
         * peep-hole on basic block
         */
        if(!debug['R'] || debug['P'])
                peep();

        /*
         * pass 8
         * recalculate pc
         */
        val = initpc;
        for(r = firstr; r != R; r = r1) {
                r->pc = val;
                p = r->prog;
                p1 = P;
                r1 = r->link;
                if(r1 != R)
                        p1 = r1->prog;
                for(; p != p1; p = p->link) {
                        switch(p->as) {
                        default:
                                val++;
                                break;

                        case ANOP:
                        case ADATA:
                        case AGLOBL:
                        case ANAME:
                        case ASIGNAME:
                        case AFUNCDATA:
                                break;
                        }
                }
        }
        pc = val;

        /*
         * fix up branches
         */
        if(debug['R'])
                if(bany(&addrs))
                        print("addrs: %B\n", addrs);

        r1 = 0; /* set */
        for(r = firstr; r != R; r = r->link) {
                p = r->prog;
                if(p->to.type == D_BRANCH) {
                        p->to.offset = r->s2->pc;
                        p->to.u.branch = r->s2->prog;
                }
                r1 = r;
        }

        /*
         * last pass
         * eliminate nops
         * free aux structures
         */
        for(p = firstr->prog; p != P; p = p->link){
                while(p->link && p->link->as == ANOP)
                        p->link = p->link->link;
        }
        if(r1 != R) {
                r1->link = freer;
                freer = firstr;
        }
}

void
addsplits(void)
{
        Reg *r, *r1;
        int z, i;
        Bits bit;

        for(r = firstr; r != R; r = r->link) {
                if(r->loop > 1)
                        continue;
                if(r->prog->as == ABL)
                        continue;
                for(r1 = r->p2; r1 != R; r1 = r1->p2link) {
                        if(r1->loop <= 1)
                                continue;
                        for(z=0; z<BITS; z++)
                                bit.b[z] = r1->calbehind.b[z] &
                                        (r->refahead.b[z] | r->use1.b[z] | r->use2.b[z]) &
                                        ~(r->calahead.b[z] & addrs.b[z]);
                        while(bany(&bit)) {
                                i = bnum(bit);
                                bit.b[i/32] &= ~(1L << (i%32));
                        }
                }
        }
}

/*
 * add mov b,rn
 * just after r
 */
void
addmove(Reg *r, int bn, int rn, int f)
{
        Prog *p, *p1;
        Addr *a;
        Var *v;

        p1 = alloc(sizeof(*p1));
        *p1 = zprog;
        p = r->prog;

        p1->link = p->link;
        p->link = p1;
        p1->lineno = p->lineno;

        v = var + bn;

        a = &p1->to;
        a->sym = v->sym;
        a->name = v->name;
        a->offset = v->offset;
        a->etype = v->etype;
        a->type = D_OREG;
        if(a->etype == TARRAY || a->sym == nil)
                a->type = D_CONST;

        p1->as = AMOVW;
        if(v->etype == TCHAR || v->etype == TUCHAR)
                p1->as = AMOVBS;
        if(v->etype == TSHORT || v->etype == TUSHORT)
                p1->as = AMOVHS;
        if(v->etype == TFLOAT)
                p1->as = AMOVF;
        if(v->etype == TDOUBLE)
                p1->as = AMOVD;

        p1->from.type = D_REG;
        p1->from.reg = rn;
        if(rn >= NREG) {
                p1->from.type = D_FREG;
                p1->from.reg = rn-NREG;
        }
        if(!f) {
                p1->from = *a;
                *a = zprog.from;
                a->type = D_REG;
                a->reg = rn;
                if(rn >= NREG) {
                        a->type = D_FREG;
                        a->reg = rn-NREG;
                }
                if(v->etype == TUCHAR)
                        p1->as = AMOVBU;
                if(v->etype == TUSHORT)
                        p1->as = AMOVHU;
        }
        if(debug['R'])
                print("%P\t.a%P\n", p, p1);
}

Bits
mkvar(Addr *a, int docon)
{
        Var *v;
        int i, t, n, et, z;
        int32 o;
        Bits bit;
        LSym *s;

        t = a->type;
        if(t == D_REG && a->reg != NREG)
                regbits |= RtoB(a->reg);
        if(t == D_FREG && a->reg != NREG)
                regbits |= FtoB(a->reg);
        s = a->sym;
        o = a->offset;
        et = a->etype;
        if(s == nil) {
                if(t != D_CONST || !docon || a->reg != NREG)
                        goto none;
                et = TLONG;
        }
        if(t == D_CONST) {
                if(s == nil && sval(o))
                        goto none;
        }

        n = a->name;
        v = var;
        for(i=0; i<nvar; i++) {
                if(s == v->sym)
                if(n == v->name)
                if(o == v->offset)
                        goto out;
                v++;
        }
        if(s)
                if(s->name[0] == '.')
                        goto none;
        if(nvar >= NVAR) {
                if(debug['w'] > 1 && s)
                        warn(Z, "variable not optimized: %s", s->name);
                goto none;
        }
        i = nvar;
        nvar++;
        v = &var[i];
        v->sym = s;
        v->offset = o;
        v->etype = et;
        v->name = n;
        if(debug['R'])
                print("bit=%2d et=%2d %D\n", i, et, a);
out:
        bit = blsh(i);
        if(n == D_EXTERN || n == D_STATIC)
                for(z=0; z<BITS; z++)
                        externs.b[z] |= bit.b[z];
        if(n == D_PARAM)
                for(z=0; z<BITS; z++)
                        params.b[z] |= bit.b[z];
        if(v->etype != et || !typechlpfd[et])   /* funny punning */
                for(z=0; z<BITS; z++)
                        addrs.b[z] |= bit.b[z];
        if(t == D_CONST) {
                if(s == nil) {
                        for(z=0; z<BITS; z++)
                                consts.b[z] |= bit.b[z];
                        return bit;
                }
                if(et != TARRAY)
                        for(z=0; z<BITS; z++)
                                addrs.b[z] |= bit.b[z];
                for(z=0; z<BITS; z++)
                        params.b[z] |= bit.b[z];
                return bit;
        }
        if(t == D_OREG)
                return bit;

none:
        return zbits;
}

void
prop(Reg *r, Bits ref, Bits cal)
{
        Reg *r1, *r2;
        int z;

        for(r1 = r; r1 != R; r1 = r1->p1) {
                for(z=0; z<BITS; z++) {
                        ref.b[z] |= r1->refahead.b[z];
                        if(ref.b[z] != r1->refahead.b[z]) {
                                r1->refahead.b[z] = ref.b[z];
                                change++;
                        }
                        cal.b[z] |= r1->calahead.b[z];
                        if(cal.b[z] != r1->calahead.b[z]) {
                                r1->calahead.b[z] = cal.b[z];
                                change++;
                        }
                }
                switch(r1->prog->as) {
                case ABL:
                        for(z=0; z<BITS; z++) {
                                cal.b[z] |= ref.b[z] | externs.b[z];
                                ref.b[z] = 0;
                        }
                        break;

                case ATEXT:
                        for(z=0; z<BITS; z++) {
                                cal.b[z] = 0;
                                ref.b[z] = 0;
                        }
                        break;

                case ARET:
                        for(z=0; z<BITS; z++) {
                                cal.b[z] = externs.b[z];
                                ref.b[z] = 0;
                        }
                }
                for(z=0; z<BITS; z++) {
                        ref.b[z] = (ref.b[z] & ~r1->set.b[z]) |
                                r1->use1.b[z] | r1->use2.b[z];
                        cal.b[z] &= ~(r1->set.b[z] | r1->use1.b[z] | r1->use2.b[z]);
                        r1->refbehind.b[z] = ref.b[z];
                        r1->calbehind.b[z] = cal.b[z];
                }
                if(r1->active)
                        break;
                r1->active = 1;
        }
        for(; r != r1; r = r->p1)
                for(r2 = r->p2; r2 != R; r2 = r2->p2link)
                        prop(r2, r->refbehind, r->calbehind);
}

/*
 * find looping structure
 *
 * 1) find reverse postordering
 * 2) find approximate dominators,
 *      the actual dominators if the flow graph is reducible
 *      otherwise, dominators plus some other non-dominators.
 *      See Matthew S. Hecht and Jeffrey D. Ullman,
 *      "Analysis of a Simple Algorithm for Global Data Flow Problems",
 *      Conf.  Record of ACM Symp. on Principles of Prog. Langs, Boston, Massachusetts,
 *      Oct. 1-3, 1973, pp.  207-217.
 * 3) find all nodes with a predecessor dominated by the current node.
 *      such a node is a loop head.
 *      recursively, all preds with a greater rpo number are in the loop
 */
int32
postorder(Reg *r, Reg **rpo2r, int32 n)
{
        Reg *r1;

        r->rpo = 1;
        r1 = r->s1;
        if(r1 && !r1->rpo)
                n = postorder(r1, rpo2r, n);
        r1 = r->s2;
        if(r1 && !r1->rpo)
                n = postorder(r1, rpo2r, n);
        rpo2r[n] = r;
        n++;
        return n;
}

int32
rpolca(int32 *idom, int32 rpo1, int32 rpo2)
{
        int32 t;

        if(rpo1 == -1)
                return rpo2;
        while(rpo1 != rpo2){
                if(rpo1 > rpo2){
                        t = rpo2;
                        rpo2 = rpo1;
                        rpo1 = t;
                }
                while(rpo1 < rpo2){
                        t = idom[rpo2];
                        if(t >= rpo2)
                                fatal(Z, "bad idom");
                        rpo2 = t;
                }
        }
        return rpo1;
}

int
doms(int32 *idom, int32 r, int32 s)
{
        while(s > r)
                s = idom[s];
        return s == r;
}

int
loophead(int32 *idom, Reg *r)
{
        int32 src;

        src = r->rpo;
        if(r->p1 != R && doms(idom, src, r->p1->rpo))
                return 1;
        for(r = r->p2; r != R; r = r->p2link)
                if(doms(idom, src, r->rpo))
                        return 1;
        return 0;
}

void
loopmark(Reg **rpo2r, int32 head, Reg *r)
{
        if(r->rpo < head || r->active == head)
                return;
        r->active = head;
        r->loop += LOOP;
        if(r->p1 != R)
                loopmark(rpo2r, head, r->p1);
        for(r = r->p2; r != R; r = r->p2link)
                loopmark(rpo2r, head, r);
}

void
loopit(Reg *r, int32 nr)
{
        Reg *r1;
        int32 i, d, me;

        if(nr > maxnr) {
                rpo2r = alloc(nr * sizeof(Reg*));
                idom = alloc(nr * sizeof(int32));
                maxnr = nr;
        }
        d = postorder(r, rpo2r, 0);
        if(d > nr)
                fatal(Z, "too many reg nodes");
        nr = d;
        for(i = 0; i < nr / 2; i++){
                r1 = rpo2r[i];
                rpo2r[i] = rpo2r[nr - 1 - i];
                rpo2r[nr - 1 - i] = r1;
        }
        for(i = 0; i < nr; i++)
                rpo2r[i]->rpo = i;

        idom[0] = 0;
        for(i = 0; i < nr; i++){
                r1 = rpo2r[i];
                me = r1->rpo;
                d = -1;
                if(r1->p1 != R && r1->p1->rpo < me)
                        d = r1->p1->rpo;
                for(r1 = r1->p2; r1 != nil; r1 = r1->p2link)
                        if(r1->rpo < me)
                                d = rpolca(idom, d, r1->rpo);
                idom[i] = d;
        }

        for(i = 0; i < nr; i++){
                r1 = rpo2r[i];
                r1->loop++;
                if(r1->p2 != R && loophead(idom, r1))
                        loopmark(rpo2r, i, r1);
        }
}

void
synch(Reg *r, Bits dif)
{
        Reg *r1;
        int z;

        for(r1 = r; r1 != R; r1 = r1->s1) {
                for(z=0; z<BITS; z++) {
                        dif.b[z] = (dif.b[z] &
                                ~(~r1->refbehind.b[z] & r1->refahead.b[z])) |
                                        r1->set.b[z] | r1->regdiff.b[z];
                        if(dif.b[z] != r1->regdiff.b[z]) {
                                r1->regdiff.b[z] = dif.b[z];
                                change++;
                        }
                }
                if(r1->active)
                        break;
                r1->active = 1;
                for(z=0; z<BITS; z++)
                        dif.b[z] &= ~(~r1->calbehind.b[z] & r1->calahead.b[z]);
                if(r1->s2 != R)
                        synch(r1->s2, dif);
        }
}

uint32
allreg(uint32 b, Rgn *r)
{
        Var *v;
        int i;

        v = var + r->varno;
        r->regno = 0;
        switch(v->etype) {

        default:
                diag(Z, "unknown etype %d/%d", bitno(b), v->etype);
                break;

        case TCHAR:
        case TUCHAR:
        case TSHORT:
        case TUSHORT:
        case TINT:
        case TUINT:
        case TLONG:
        case TULONG:
        case TIND:
        case TARRAY:
                i = BtoR(~b);
                if(i && r->cost >= 0) {
                        r->regno = i;
                        return RtoB(i);
                }
                break;

        case TVLONG:
        case TDOUBLE:
        case TFLOAT:
                i = BtoF(~b);
                if(i && r->cost >= 0) {
                        r->regno = i+NREG;
                        return FtoB(i);
                }
                break;
        }
        return 0;
}

void
paint1(Reg *r, int bn)
{
        Reg *r1;
        Prog *p;
        int z;
        uint32 bb;

        z = bn/32;
        bb = 1L<<(bn%32);
        if(r->act.b[z] & bb)
                return;
        for(;;) {
                if(!(r->refbehind.b[z] & bb))
                        break;
                r1 = r->p1;
                if(r1 == R)
                        break;
                if(!(r1->refahead.b[z] & bb))
                        break;
                if(r1->act.b[z] & bb)
                        break;
                r = r1;
        }

        if(LOAD(r) & ~(r->set.b[z] & ~(r->use1.b[z]|r->use2.b[z])) & bb) {
                change -= CLOAD * r->loop;
                if(debug['R'] && debug['v'])
                        print("%d%P\td %B $%d\n", r->loop,
                                r->prog, blsh(bn), change);
        }
        for(;;) {
                r->act.b[z] |= bb;
                p = r->prog;

                if(r->use1.b[z] & bb) {
                        change += CREF * r->loop;
                        if(debug['R'] && debug['v'])
                                print("%d%P\tu1 %B $%d\n", r->loop,
                                        p, blsh(bn), change);
                }

                if((r->use2.b[z]|r->set.b[z]) & bb) {
                        change += CREF * r->loop;
                        if(debug['R'] && debug['v'])
                                print("%d%P\tu2 %B $%d\n", r->loop,
                                        p, blsh(bn), change);
                }

                if(STORE(r) & r->regdiff.b[z] & bb) {
                        change -= CLOAD * r->loop;
                        if(debug['R'] && debug['v'])
                                print("%d%P\tst %B $%d\n", r->loop,
                                        p, blsh(bn), change);
                }

                if(r->refbehind.b[z] & bb)
                        for(r1 = r->p2; r1 != R; r1 = r1->p2link)
                                if(r1->refahead.b[z] & bb)
                                        paint1(r1, bn);

                if(!(r->refahead.b[z] & bb))
                        break;
                r1 = r->s2;
                if(r1 != R)
                        if(r1->refbehind.b[z] & bb)
                                paint1(r1, bn);
                r = r->s1;
                if(r == R)
                        break;
                if(r->act.b[z] & bb)
                        break;
                if(!(r->refbehind.b[z] & bb))
                        break;
        }
}

uint32
paint2(Reg *r, int bn)
{
        Reg *r1;
        int z;
        uint32 bb, vreg;

        z = bn/32;
        bb = 1L << (bn%32);
        vreg = regbits;
        if(!(r->act.b[z] & bb))
                return vreg;
        for(;;) {
                if(!(r->refbehind.b[z] & bb))
                        break;
                r1 = r->p1;
                if(r1 == R)
                        break;
                if(!(r1->refahead.b[z] & bb))
                        break;
                if(!(r1->act.b[z] & bb))
                        break;
                r = r1;
        }
        for(;;) {
                r->act.b[z] &= ~bb;

                vreg |= r->regu;

                if(r->refbehind.b[z] & bb)
                        for(r1 = r->p2; r1 != R; r1 = r1->p2link)
                                if(r1->refahead.b[z] & bb)
                                        vreg |= paint2(r1, bn);

                if(!(r->refahead.b[z] & bb))
                        break;
                r1 = r->s2;
                if(r1 != R)
                        if(r1->refbehind.b[z] & bb)
                                vreg |= paint2(r1, bn);
                r = r->s1;
                if(r == R)
                        break;
                if(!(r->act.b[z] & bb))
                        break;
                if(!(r->refbehind.b[z] & bb))
                        break;
        }
        return vreg;
}

void
paint3(Reg *r, int bn, int32 rb, int rn)
{
        Reg *r1;
        Prog *p;
        int z;
        uint32 bb;

        z = bn/32;
        bb = 1L << (bn%32);
        if(r->act.b[z] & bb)
                return;
        for(;;) {
                if(!(r->refbehind.b[z] & bb))
                        break;
                r1 = r->p1;
                if(r1 == R)
                        break;
                if(!(r1->refahead.b[z] & bb))
                        break;
                if(r1->act.b[z] & bb)
                        break;
                r = r1;
        }

        if(LOAD(r) & ~(r->set.b[z] & ~(r->use1.b[z]|r->use2.b[z])) & bb)
                addmove(r, bn, rn, 0);
        for(;;) {
                r->act.b[z] |= bb;
                p = r->prog;

                if(r->use1.b[z] & bb) {
                        if(debug['R'])
                                print("%P", p);
                        addreg(&p->from, rn);
                        if(debug['R'])
                                print("\t.c%P\n", p);
                }
                if((r->use2.b[z]|r->set.b[z]) & bb) {
                        if(debug['R'])
                                print("%P", p);
                        addreg(&p->to, rn);
                        if(debug['R'])
                                print("\t.c%P\n", p);
                }

                if(STORE(r) & r->regdiff.b[z] & bb)
                        addmove(r, bn, rn, 1);
                r->regu |= rb;

                if(r->refbehind.b[z] & bb)
                        for(r1 = r->p2; r1 != R; r1 = r1->p2link)
                                if(r1->refahead.b[z] & bb)
                                        paint3(r1, bn, rb, rn);

                if(!(r->refahead.b[z] & bb))
                        break;
                r1 = r->s2;
                if(r1 != R)
                        if(r1->refbehind.b[z] & bb)
                                paint3(r1, bn, rb, rn);
                r = r->s1;
                if(r == R)
                        break;
                if(r->act.b[z] & bb)
                        break;
                if(!(r->refbehind.b[z] & bb))
                        break;
        }
}

void
addreg(Addr *a, int rn)
{

        a->sym = 0;
        a->name = D_NONE;
        a->type = D_REG;
        a->reg = rn;
        if(rn >= NREG) {
                a->type = D_FREG;
                a->reg = rn-NREG;
        }
}

/*
 *      bit     reg
 *      0       R0
 *      1       R1
 *      ...     ...
 *      10      R10
 *      12  R12
 */
int32
RtoB(int r)
{

        if(r < 2 || (r >= REGTMP-2 && r != 12)) // excluded R9 and R10 for m and g, but not R12
                return 0;
        return 1L << r;
}

int
BtoR(int32 b)
{
        b &= 0x11fcL;   // excluded R9 and R10 for m and g, but not R12
        if(b == 0)
                return 0;
        return bitno(b);
}

/*
 *      bit     reg
 *      18      F2
 *      19      F3
 *      ...     ...
 *      31      F15
 */
int32
FtoB(int f)
{

        if(f < 2 || f > NFREG-1)
                return 0;
        return 1L << (f + 16);
}

int
BtoF(int32 b)
{

        b &= 0xfffc0000L;
        if(b == 0)
                return 0;
        return bitno(b) - 16;
}

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