ref: 53fbb0515159465421053c3165b1aa9da196aa4d
dir: /sys/src/cmd/cc/scon.c/
#include "cc.h" static Node* acast(Type *t, Node *n) { if(n->type->etype != t->etype || n->op == OBIT) { n = new1(OCAST, n, Z); if(nocast(n->left->type, t)) *n = *n->left; n->type = t; } return n; } void evconst(Node *n) { Node *l, *r; int et, isf; vlong v; double d; if(n == Z || n->type == T) return; et = n->type->etype; isf = typefd[et]; l = n->left; r = n->right; d = 0; v = 0; switch(n->op) { default: return; case ONEG: if(isf) d = -l->fconst; else v = -l->vconst; break; case OCOM: v = ~l->vconst; break; case OCAST: if(et == TVOID) return; et = l->type->etype; if(isf) { if(typefd[et]) d = l->fconst; else d = l->vconst; } else { if(typefd[et]) v = l->fconst; else v = convvtox(l->vconst, n->type->etype); } break; case OCONST: break; case OADD: if(isf) d = l->fconst + r->fconst; else { v = l->vconst + r->vconst; } break; case OSUB: if(isf) d = l->fconst - r->fconst; else v = l->vconst - r->vconst; break; case OMUL: if(isf) d = l->fconst * r->fconst; else { v = l->vconst * r->vconst; } break; case OLMUL: v = (uvlong)l->vconst * (uvlong)r->vconst; break; case ODIV: if(vconst(r) == 0) { warn(n, "divide by zero"); return; } if(isf) d = l->fconst / r->fconst; else v = l->vconst / r->vconst; break; case OLDIV: if(vconst(r) == 0) { warn(n, "divide by zero"); return; } v = (uvlong)l->vconst / (uvlong)r->vconst; break; case OMOD: if(vconst(r) == 0) { warn(n, "modulo by zero"); return; } v = l->vconst % r->vconst; break; case OLMOD: if(vconst(r) == 0) { warn(n, "modulo by zero"); return; } v = (uvlong)l->vconst % (uvlong)r->vconst; break; case OAND: v = l->vconst & r->vconst; break; case OOR: v = l->vconst | r->vconst; break; case OXOR: v = l->vconst ^ r->vconst; break; case OLSHR: v = (uvlong)l->vconst >> r->vconst; break; case OASHR: v = l->vconst >> r->vconst; break; case OASHL: v = l->vconst << r->vconst; break; case OLO: v = (uvlong)l->vconst < (uvlong)r->vconst; break; case OLT: if(typefd[l->type->etype]) v = l->fconst < r->fconst; else v = l->vconst < r->vconst; break; case OHI: v = (uvlong)l->vconst > (uvlong)r->vconst; break; case OGT: if(typefd[l->type->etype]) v = l->fconst > r->fconst; else v = l->vconst > r->vconst; break; case OLS: v = (uvlong)l->vconst <= (uvlong)r->vconst; break; case OLE: if(typefd[l->type->etype]) v = l->fconst <= r->fconst; else v = l->vconst <= r->vconst; break; case OHS: v = (uvlong)l->vconst >= (uvlong)r->vconst; break; case OGE: if(typefd[l->type->etype]) v = l->fconst >= r->fconst; else v = l->vconst >= r->vconst; break; case OEQ: if(typefd[l->type->etype]) v = l->fconst == r->fconst; else v = l->vconst == r->vconst; break; case ONE: if(typefd[l->type->etype]) v = l->fconst != r->fconst; else v = l->vconst != r->vconst; break; case ONOT: if(typefd[l->type->etype]) v = !l->fconst; else v = !l->vconst; break; case OANDAND: if(typefd[l->type->etype]) v = l->fconst && r->fconst; else v = l->vconst && r->vconst; break; case OOROR: if(typefd[l->type->etype]) v = l->fconst || r->fconst; else v = l->vconst || r->vconst; break; } if(isf) { n->fconst = d; } else { n->vconst = convvtox(v, n->type->etype); } n->oldop = n->op; n->op = OCONST; } void acom(Node *n) { Type *t; Node *l, *r; int i; switch(n->op) { case ONAME: case OCONST: case OSTRING: case OINDREG: case OREGISTER: return; case ONEG: l = n->left; if(addo(n) && addo(l)) break; acom(l); return; case OADD: case OSUB: case OMUL: l = n->left; r = n->right; if(addo(n)) { if(addo(r)) break; if(addo(l)) break; } acom(l); acom(r); return; default: l = n->left; r = n->right; if(l != Z) acom(l); if(r != Z) acom(r); return; } /* bust terms out */ t = n->type; term[0].mult = 0; term[0].node = Z; nterm = 1; acom1(1, n); if(debug['m']) for(i=0; i<nterm; i++) { print("%d %3lld ", i, term[i].mult); prtree1(term[i].node, 1, 0); } if(nterm < NTERM) acom2(n, t); n->type = t; } int acomcmp1(const void *a1, const void *a2) { vlong c1, c2; Term *t1, *t2; t1 = (Term*)a1; t2 = (Term*)a2; c1 = t1->mult; if(c1 < 0) c1 = -c1; c2 = t2->mult; if(c2 < 0) c2 = -c2; if(c1 > c2) return 1; if(c1 < c2) return -1; c1 = 1; if(t1->mult < 0) c1 = 0; c2 = 1; if(t2->mult < 0) c2 = 0; if(c2 -= c1) return c2; if(t2 > t1) return 1; return -1; } int acomcmp2(const void *a1, const void *a2) { vlong c1, c2; Term *t1, *t2; t1 = (Term*)a1; t2 = (Term*)a2; c1 = t1->mult; c2 = t2->mult; if(c1 > c2) return 1; if(c1 < c2) return -1; if(t2 > t1) return 1; return -1; } void acom2(Node *n, Type *t) { Node *l, *r; Term trm[NTERM]; int et, nt, i, j; vlong c1, c2; /* * copy into automatic */ c2 = 0; nt = nterm; for(i=0; i<nt; i++) trm[i] = term[i]; /* * recur on subtrees */ j = 0; for(i=1; i<nt; i++) { c1 = trm[i].mult; if(c1 == 0) continue; l = trm[i].node; if(l != Z) { j = 1; acom(l); } } c1 = trm[0].mult; if(j == 0) { n->oldop = n->op; n->op = OCONST; n->vconst = c1; return; } et = t->etype; /* * prepare constant term, * combine it with an addressing term */ if(c1 != 0) { l = new1(OCONST, Z, Z); l->type = t; l->vconst = c1; trm[0].mult = 1; for(i=1; i<nt; i++) { if(trm[i].mult != 1) continue; r = trm[i].node; if(r->op != OADDR) continue; r->type = t; l = new1(OADD, r, l); l->type = t; trm[i].mult = 0; break; } trm[0].node = l; } /* * look for factorable terms * c1*i + c1*c2*j -> c1*(i + c2*j) */ qsort(trm+1, nt-1, sizeof(trm[0]), acomcmp1); for(i=nt-1; i>=0; i--) { c1 = trm[i].mult; if(c1 < 0) c1 = -c1; if(c1 <= 1) continue; for(j=i+1; j<nt; j++) { c2 = trm[j].mult; if(c2 < 0) c2 = -c2; if(c2 <= 1) continue; if(c2 % c1) continue; r = trm[j].node; if(r->type->etype != et) r = acast(t, r); c2 = trm[j].mult/trm[i].mult; if(c2 != 1 && c2 != -1) { r = new1(OMUL, r, new(OCONST, Z, Z)); r->type = t; r->right->type = t; r->right->vconst = c2; } l = trm[i].node; if(l->type->etype != et) l = acast(t, l); r = new1(OADD, l, r); r->type = t; if(c2 == -1) r->op = OSUB; trm[i].node = r; trm[j].mult = 0; } } if(debug['m']) { print("\n"); for(i=0; i<nt; i++) { print("%d %3lld ", i, trm[i].mult); prtree1(trm[i].node, 1, 0); } } /* * put it all back together */ qsort(trm+1, nt-1, sizeof(trm[0]), acomcmp2); l = Z; for(i=nt-1; i>=0; i--) { c1 = trm[i].mult; if(c1 == 0) continue; r = trm[i].node; if(r->type->etype != et || r->op == OBIT) r = acast(t, r); if(c1 != 1 && c1 != -1) { r = new1(OMUL, r, new(OCONST, Z, Z)); r->type = t; r->right->type = t; if(c1 < 0) { r->right->vconst = -c1; c1 = -1; } else { r->right->vconst = c1; c1 = 1; } } if(l == Z) { l = r; c2 = c1; continue; } if(c1 < 0) if(c2 < 0) l = new1(OADD, l, r); else l = new1(OSUB, l, r); else if(c2 < 0) { l = new1(OSUB, r, l); c2 = 1; } else l = new1(OADD, l, r); l->type = t; } if(c2 < 0) { r = new1(OCONST, 0, 0); r->vconst = 0; r->type = t; l = new1(OSUB, r, l); l->type = t; } *n = *l; } void acom1(vlong v, Node *n) { Node *l, *r; if(v == 0 || nterm >= NTERM) return; if(!addo(n)) { if(n->op == OCONST) if(!typefd[n->type->etype]) { term[0].mult += v*n->vconst; return; } term[nterm].mult = v; term[nterm].node = n; nterm++; return; } switch(n->op) { case OCAST: acom1(v, n->left); break; case ONEG: acom1(-v, n->left); break; case OADD: acom1(v, n->left); acom1(v, n->right); break; case OSUB: acom1(v, n->left); acom1(-v, n->right); break; case OMUL: l = n->left; r = n->right; if(l->op == OCONST) if(!typefd[n->type->etype]) { acom1(v*l->vconst, r); break; } if(r->op == OCONST) if(!typefd[n->type->etype]) { acom1(v*r->vconst, l); break; } break; default: diag(n, "not addo"); } } int addo(Node *n) { if(n != Z) if(!typefd[n->type->etype]) if(!typev[n->type->etype] || ewidth[TVLONG] == ewidth[TIND]) switch(n->op) { case OCAST: if(nilcast(n->left->type, n->type)) return 1; break; case ONEG: case OADD: case OSUB: return 1; case OMUL: if(n->left->op == OCONST) return 1; if(n->right->op == OCONST) return 1; } return 0; }