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hellwig |
#include "c.h"
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#include <float.h>
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static char rcsid[] = "$Id: simp.c,v 1.1 2002/08/28 23:12:45 drh Exp $";
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#define foldcnst(TYPE,VAR,OP) \
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if (l->op == CNST+TYPE && r->op == CNST+TYPE) \
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return cnsttree(ty, l->u.v.VAR OP r->u.v.VAR)
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#define commute(L,R) \
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if (generic(R->op) == CNST && generic(L->op) != CNST) \
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do { Tree t = L; L = R; R = t; } while(0)
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#define xfoldcnst(TYPE,VAR,OP,FUNC)\
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if (l->op == CNST+TYPE && r->op == CNST+TYPE\
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&& FUNC(l->u.v.VAR,r->u.v.VAR,\
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ty->u.sym->u.limits.min.VAR,\
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ty->u.sym->u.limits.max.VAR, needconst)) \
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return cnsttree(ty, l->u.v.VAR OP r->u.v.VAR)
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#define xcvtcnst(FTYPE,SRC,DST,VAR,EXPR) \
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if (l->op == CNST+FTYPE) do {\
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if (!explicitCast\
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&& ((SRC) < DST->u.sym->u.limits.min.VAR || (SRC) > DST->u.sym->u.limits.max.VAR))\
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warning("overflow in converting constant expression from `%t' to `%t'\n", l->type, DST);\
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if (needconst\
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|| !((SRC) < DST->u.sym->u.limits.min.VAR || (SRC) > DST->u.sym->u.limits.max.VAR))\
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return cnsttree(ty, (EXPR)); } while(0)
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#define identity(X,Y,TYPE,VAR,VAL) \
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if (X->op == CNST+TYPE && X->u.v.VAR == VAL) return Y
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#define zerofield(OP,TYPE,VAR) \
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if (l->op == FIELD \
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&& r->op == CNST+TYPE && r->u.v.VAR == 0)\
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return eqtree(OP, bittree(BAND, l->kids[0],\
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cnsttree(unsignedtype, \
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(unsigned long)fieldmask(l->u.field)<<fieldright(l->u.field))), r)
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#define cfoldcnst(TYPE,VAR,OP) \
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if (l->op == CNST+TYPE && r->op == CNST+TYPE) \
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return cnsttree(inttype, (long)(l->u.v.VAR OP r->u.v.VAR))
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#define foldaddp(L,R,RTYPE,VAR) \
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if (L->op == CNST+P && R->op == CNST+RTYPE) { \
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Tree e = tree(CNST+P, ty, NULL, NULL);\
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e->u.v.p = (char *)L->u.v.p + R->u.v.VAR;\
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return e; }
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#define ufoldcnst(TYPE,EXP) if (l->op == CNST+TYPE) return EXP
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#define sfoldcnst(OP) \
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if (l->op == CNST+U && r->op == CNST+I \
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&& r->u.v.i >= 0 && r->u.v.i < 8*l->type->size) \
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return cnsttree(ty, (unsigned long)(l->u.v.u OP r->u.v.i))
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#define geu(L,R,V) \
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if (R->op == CNST+U && R->u.v.u == 0) do { \
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warning("result of unsigned comparison is constant\n"); \
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return tree(RIGHT, inttype, root(L), cnsttree(inttype, (long)(V))); } while(0)
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#define idempotent(OP) if (l->op == OP) return l->kids[0]
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int needconst;
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int explicitCast;
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static int addi(long x, long y, long min, long max, int needconst) {
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int cond = x == 0 || y == 0
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|| x < 0 && y < 0 && x >= min - y
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|| x < 0 && y > 0
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|| x > 0 && y < 0
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|| x > 0 && y > 0 && x <= max - y;
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if (!cond && needconst) {
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warning("overflow in constant expression\n");
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cond = 1;
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}
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return cond;
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}
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static int addd(double x, double y, double min, double max, int needconst) {
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int cond = x == 0 || y == 0
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|| x < 0 && y < 0 && x >= min - y
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|| x < 0 && y > 0
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|| x > 0 && y < 0
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|| x > 0 && y > 0 && x <= max - y;
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if (!cond && needconst) {
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warning("overflow in constant expression\n");
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cond = 1;
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}
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return cond;
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}
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static Tree addrtree(Tree e, long n, Type ty) {
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Symbol p = e->u.sym, q;
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if (p->scope == GLOBAL
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|| p->sclass == STATIC || p->sclass == EXTERN)
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NEW0(q, PERM);
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else
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NEW0(q, FUNC);
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q->name = stringd(genlabel(1));
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q->sclass = p->sclass;
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q->scope = p->scope;
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assert(isptr(ty) || isarray(ty));
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q->type = isptr(ty) ? ty->type : ty;
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q->temporary = p->temporary;
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q->generated = p->generated;
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q->addressed = p->addressed;
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q->computed = 1;
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q->defined = 1;
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q->ref = 1;
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assert(IR->address);
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if (p->scope == GLOBAL
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|| p->sclass == STATIC || p->sclass == EXTERN) {
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if (p->sclass == AUTO)
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q->sclass = STATIC;
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(*IR->address)(q, p, n);
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} else {
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Code cp;
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addlocal(p);
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cp = code(Address);
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cp->u.addr.sym = q;
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cp->u.addr.base = p;
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cp->u.addr.offset = n;
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}
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e = tree(e->op, ty, NULL, NULL);
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e->u.sym = q;
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return e;
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}
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/* div[id] - return 1 if min <= x/y <= max, 0 otherwise */
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static int divi(long x, long y, long min, long max, int needconst) {
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| 125 |
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int cond = y != 0 && !(x == min && y == -1);
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if (!cond && needconst) {
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warning("overflow in constant expression\n");
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| 128 |
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cond = 1;
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| 129 |
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}
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| 130 |
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return cond;
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}
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static int divd(double x, double y, double min, double max, int needconst) {
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int cond;
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if (x < 0) x = -x;
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if (y < 0) y = -y;
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cond = y != 0 && !(y < 1 && x > max*y);
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if (!cond && needconst) {
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warning("overflow in constant expression\n");
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cond = 1;
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}
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return cond;
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}
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/* mul[id] - return 1 if min <= x*y <= max, 0 otherwise */
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static int muli(long x, long y, long min, long max, int needconst) {
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int cond = x > -1 && x <= 1 || y > -1 && y <= 1
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|| x < 0 && y < 0 && -x <= max/-y
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|| x < 0 && y > 0 && x >= min/y
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|| x > 0 && y < 0 && y >= min/x
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|| x > 0 && y > 0 && x <= max/y;
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if (!cond && needconst) {
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warning("overflow in constant expression\n");
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cond = 1;
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}
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return cond;
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}
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static int muld(double x, double y, double min, double max, int needconst) {
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int cond = x >= -1 && x <= 1 || y >= -1 && y <= 1
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|| x < 0 && y < 0 && -x <= max/-y
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|| x < 0 && y > 0 && x >= min/y
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|| x > 0 && y < 0 && y >= min/x
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| 170 |
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|| x > 0 && y > 0 && x <= max/y;
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if (!cond && needconst) {
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warning("overflow in constant expression\n");
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| 173 |
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cond = 1;
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| 174 |
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}
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| 175 |
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return cond;
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| 177 |
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| 178 |
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}
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| 179 |
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/* sub[id] - return 1 if min <= x-y <= max, 0 otherwise */
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static int subi(long x, long y, long min, long max, int needconst) {
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| 181 |
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return addi(x, -y, min, max, needconst);
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| 182 |
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}
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| 183 |
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| 184 |
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static int subd(double x, double y, double min, double max, int needconst) {
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| 185 |
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return addd(x, -y, min, max, needconst);
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| 186 |
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}
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| 187 |
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Tree constexpr(int tok) {
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| 188 |
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Tree p;
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| 189 |
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| 190 |
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needconst++;
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| 191 |
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p = expr1(tok);
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| 192 |
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needconst--;
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| 193 |
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return p;
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| 194 |
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}
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| 195 |
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| 196 |
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int intexpr(int tok, int n) {
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| 197 |
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Tree p = constexpr(tok);
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| 198 |
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| 199 |
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needconst++;
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| 200 |
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if (p->op == CNST+I || p->op == CNST+U)
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| 201 |
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n = cast(p, inttype)->u.v.i;
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| 202 |
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else
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| 203 |
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error("integer expression must be constant\n");
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| 204 |
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needconst--;
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| 205 |
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return n;
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| 206 |
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}
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| 207 |
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Tree simplify(int op, Type ty, Tree l, Tree r) {
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| 208 |
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int n;
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| 209 |
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Tree p;
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| 210 |
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| 211 |
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if (optype(op) == 0)
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| 212 |
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op = mkop(op, ty);
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| 213 |
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switch (op) {
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| 214 |
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case ADD+U:
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| 215 |
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foldcnst(U,u,+);
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| 216 |
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commute(r,l);
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| 217 |
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identity(r,l,U,u,0);
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| 218 |
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break;
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| 219 |
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case ADD+I:
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| 220 |
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xfoldcnst(I,i,+,addi);
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| 221 |
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commute(r,l);
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| 222 |
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identity(r,l,I,i,0);
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| 223 |
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break;
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| 224 |
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case CVI+I:
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| 225 |
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xcvtcnst(I,l->u.v.i,ty,i,(long)extend(l->u.v.i,ty));
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| 226 |
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break;
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| 227 |
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case CVU+I:
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| 228 |
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if (l->op == CNST+U) {
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| 229 |
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if (!explicitCast && l->u.v.u > ty->u.sym->u.limits.max.i)
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| 230 |
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warning("overflow in converting constant expression from `%t' to `%t'\n", l->type, ty);
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| 231 |
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if (needconst || !(l->u.v.u > ty->u.sym->u.limits.max.i))
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| 232 |
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return cnsttree(ty, (long)extend(l->u.v.u,ty));
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| 233 |
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}
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| 234 |
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break;
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| 235 |
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case CVP+U:
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| 236 |
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xcvtcnst(P,(unsigned long)l->u.v.p,ty,u,(unsigned long)l->u.v.p);
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| 237 |
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break;
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| 238 |
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case CVU+P:
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| 239 |
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xcvtcnst(U,(void*)l->u.v.u,ty,p,(void*)l->u.v.u);
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| 240 |
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break;
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| 241 |
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case CVP+P:
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| 242 |
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xcvtcnst(P,l->u.v.p,ty,p,l->u.v.p);
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| 243 |
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break;
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| 244 |
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case CVI+U:
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| 245 |
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xcvtcnst(I,l->u.v.i,ty,u,((unsigned long)l->u.v.i)&ones(8*ty->size));
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| 246 |
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break;
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| 247 |
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case CVU+U:
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| 248 |
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xcvtcnst(U,l->u.v.u,ty,u,l->u.v.u&ones(8*ty->size));
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| 249 |
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break;
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| 250 |
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| 251 |
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case CVI+F:
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| 252 |
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xcvtcnst(I,l->u.v.i,ty,d,(long double)l->u.v.i);
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| 253 |
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case CVU+F:
|
| 254 |
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xcvtcnst(U,l->u.v.u,ty,d,(long double)l->u.v.u);
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| 255 |
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break;
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| 256 |
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case CVF+I:
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| 257 |
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xcvtcnst(F,l->u.v.d,ty,i,(long)l->u.v.d);
|
| 258 |
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break;
|
| 259 |
|
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case CVF+F: {
|
| 260 |
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float d;
|
| 261 |
|
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if (l->op == CNST+F)
|
| 262 |
|
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if (l->u.v.d < ty->u.sym->u.limits.min.d)
|
| 263 |
|
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d = ty->u.sym->u.limits.min.d;
|
| 264 |
|
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else if (l->u.v.d > ty->u.sym->u.limits.max.d)
|
| 265 |
|
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d = ty->u.sym->u.limits.max.d;
|
| 266 |
|
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else
|
| 267 |
|
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d = l->u.v.d;
|
| 268 |
|
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xcvtcnst(F,l->u.v.d,ty,d,(long double)d);
|
| 269 |
|
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break;
|
| 270 |
|
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}
|
| 271 |
|
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case BAND+U:
|
| 272 |
|
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foldcnst(U,u,&);
|
| 273 |
|
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commute(r,l);
|
| 274 |
|
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identity(r,l,U,u,ones(8*ty->size));
|
| 275 |
|
|
if (r->op == CNST+U && r->u.v.u == 0)
|
| 276 |
|
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return tree(RIGHT, ty, root(l), cnsttree(ty, 0UL));
|
| 277 |
|
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break;
|
| 278 |
|
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case BAND+I:
|
| 279 |
|
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foldcnst(I,i,&);
|
| 280 |
|
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commute(r,l);
|
| 281 |
|
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identity(r,l,I,i,ones(8*ty->size));
|
| 282 |
|
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if (r->op == CNST+I && r->u.v.u == 0)
|
| 283 |
|
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return tree(RIGHT, ty, root(l), cnsttree(ty, 0L));
|
| 284 |
|
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break;
|
| 285 |
|
|
|
| 286 |
|
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case MUL+U:
|
| 287 |
|
|
commute(l,r);
|
| 288 |
|
|
if (l->op == CNST+U && (n = ispow2(l->u.v.u)) != 0)
|
| 289 |
|
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return simplify(LSH, ty, r, cnsttree(inttype, (long)n));
|
| 290 |
|
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foldcnst(U,u,*);
|
| 291 |
|
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identity(r,l,U,u,1);
|
| 292 |
|
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break;
|
| 293 |
|
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case NE+I:
|
| 294 |
|
|
cfoldcnst(I,i,!=);
|
| 295 |
|
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commute(r,l);
|
| 296 |
|
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zerofield(NE,I,i);
|
| 297 |
|
|
break;
|
| 298 |
|
|
|
| 299 |
|
|
case EQ+I:
|
| 300 |
|
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cfoldcnst(I,i,==);
|
| 301 |
|
|
commute(r,l);
|
| 302 |
|
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zerofield(EQ,I,i);
|
| 303 |
|
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break;
|
| 304 |
|
|
case ADD+P:
|
| 305 |
|
|
foldaddp(l,r,I,i);
|
| 306 |
|
|
foldaddp(l,r,U,u);
|
| 307 |
|
|
foldaddp(r,l,I,i);
|
| 308 |
|
|
foldaddp(r,l,U,u);
|
| 309 |
|
|
commute(r,l);
|
| 310 |
|
|
identity(r,retype(l,ty),I,i,0);
|
| 311 |
|
|
identity(r,retype(l,ty),U,u,0);
|
| 312 |
|
|
/*
|
| 313 |
|
|
Some assemblers, e.g., the MIPS, can't handle offsets
|
| 314 |
|
|
larger than 16 bits. A better solution would be to change
|
| 315 |
|
|
the interface so that address() could fail.
|
| 316 |
|
|
*/
|
| 317 |
|
|
if (l->op == ADDRG+P && l->u.sym->generated
|
| 318 |
|
|
&& (r->op == CNST+I && (r->u.v.i > 32767 || r->u.v.i < -32768)
|
| 319 |
|
|
|| r->op == CNST+U && r->u.v.u > 65536))
|
| 320 |
|
|
break;
|
| 321 |
|
|
if (IR->address
|
| 322 |
|
|
&& isaddrop(l->op)
|
| 323 |
|
|
&& (r->op == CNST+I && r->u.v.i <= longtype->u.sym->u.limits.max.i
|
| 324 |
|
|
&& r->u.v.i >= longtype->u.sym->u.limits.min.i
|
| 325 |
|
|
|| r->op == CNST+U && r->u.v.u <= longtype->u.sym->u.limits.max.i))
|
| 326 |
|
|
return addrtree(l, cast(r, longtype)->u.v.i, ty);
|
| 327 |
|
|
if (IR->address
|
| 328 |
|
|
&& l->op == ADD+P && isaddrop(l->kids[1]->op)
|
| 329 |
|
|
&& (r->op == CNST+I && r->u.v.i <= longtype->u.sym->u.limits.max.i
|
| 330 |
|
|
&& r->u.v.i >= longtype->u.sym->u.limits.min.i
|
| 331 |
|
|
|| r->op == CNST+U && r->u.v.u <= longtype->u.sym->u.limits.max.i))
|
| 332 |
|
|
return simplify(ADD+P, ty, l->kids[0],
|
| 333 |
|
|
addrtree(l->kids[1], cast(r, longtype)->u.v.i, ty));
|
| 334 |
|
|
if ((l->op == ADD+I || l->op == SUB+I)
|
| 335 |
|
|
&& l->kids[1]->op == CNST+I && isaddrop(r->op))
|
| 336 |
|
|
return simplify(ADD+P, ty, l->kids[0],
|
| 337 |
|
|
simplify(generic(l->op)+P, ty, r, l->kids[1]));
|
| 338 |
|
|
if (l->op == ADD+P && generic(l->kids[1]->op) == CNST
|
| 339 |
|
|
&& generic(r->op) == CNST)
|
| 340 |
|
|
return simplify(ADD+P, ty, l->kids[0],
|
| 341 |
|
|
simplify(ADD, l->kids[1]->type, l->kids[1], r));
|
| 342 |
|
|
if (l->op == ADD+I && generic(l->kids[1]->op) == CNST
|
| 343 |
|
|
&& r->op == ADD+P && generic(r->kids[1]->op) == CNST)
|
| 344 |
|
|
return simplify(ADD+P, ty, l->kids[0],
|
| 345 |
|
|
simplify(ADD+P, ty, r->kids[0],
|
| 346 |
|
|
simplify(ADD, r->kids[1]->type, l->kids[1], r->kids[1])));
|
| 347 |
|
|
if (l->op == RIGHT && l->kids[1])
|
| 348 |
|
|
return tree(RIGHT, ty, l->kids[0],
|
| 349 |
|
|
simplify(ADD+P, ty, l->kids[1], r));
|
| 350 |
|
|
else if (l->op == RIGHT && l->kids[0])
|
| 351 |
|
|
return tree(RIGHT, ty,
|
| 352 |
|
|
simplify(ADD+P, ty, l->kids[0], r), NULL);
|
| 353 |
|
|
break;
|
| 354 |
|
|
|
| 355 |
|
|
case ADD+F:
|
| 356 |
|
|
xfoldcnst(F,d,+,addd);
|
| 357 |
|
|
commute(r,l);
|
| 358 |
|
|
break;
|
| 359 |
|
|
case AND+I:
|
| 360 |
|
|
op = AND;
|
| 361 |
|
|
ufoldcnst(I,l->u.v.i ? cond(r) : l); /* 0&&r => 0, 1&&r => r */
|
| 362 |
|
|
break;
|
| 363 |
|
|
case OR+I:
|
| 364 |
|
|
op = OR;
|
| 365 |
|
|
/* 0||r => r, 1||r => 1 */
|
| 366 |
|
|
ufoldcnst(I,l->u.v.i ? cnsttree(ty, 1L) : cond(r));
|
| 367 |
|
|
break;
|
| 368 |
|
|
case BCOM+I:
|
| 369 |
|
|
ufoldcnst(I,cnsttree(ty, (long)extend((~l->u.v.i)&ones(8*ty->size), ty)));
|
| 370 |
|
|
idempotent(BCOM+U);
|
| 371 |
|
|
break;
|
| 372 |
|
|
case BCOM+U:
|
| 373 |
|
|
ufoldcnst(U,cnsttree(ty, (unsigned long)((~l->u.v.u)&ones(8*ty->size))));
|
| 374 |
|
|
idempotent(BCOM+U);
|
| 375 |
|
|
break;
|
| 376 |
|
|
case BOR+U:
|
| 377 |
|
|
foldcnst(U,u,|);
|
| 378 |
|
|
commute(r,l);
|
| 379 |
|
|
identity(r,l,U,u,0);
|
| 380 |
|
|
break;
|
| 381 |
|
|
case BOR+I:
|
| 382 |
|
|
foldcnst(I,i,|);
|
| 383 |
|
|
commute(r,l);
|
| 384 |
|
|
identity(r,l,I,i,0);
|
| 385 |
|
|
break;
|
| 386 |
|
|
case BXOR+U:
|
| 387 |
|
|
foldcnst(U,u,^);
|
| 388 |
|
|
commute(r,l);
|
| 389 |
|
|
identity(r,l,U,u,0);
|
| 390 |
|
|
break;
|
| 391 |
|
|
case BXOR+I:
|
| 392 |
|
|
foldcnst(I,i,^);
|
| 393 |
|
|
commute(r,l);
|
| 394 |
|
|
identity(r,l,I,i,0);
|
| 395 |
|
|
break;
|
| 396 |
|
|
case DIV+F:
|
| 397 |
|
|
xfoldcnst(F,d,/,divd);
|
| 398 |
|
|
break;
|
| 399 |
|
|
case DIV+I:
|
| 400 |
|
|
identity(r,l,I,i,1);
|
| 401 |
|
|
if (r->op == CNST+I && r->u.v.i == 0
|
| 402 |
|
|
|| l->op == CNST+I && l->u.v.i == ty->u.sym->u.limits.min.i
|
| 403 |
|
|
&& r->op == CNST+I && r->u.v.i == -1)
|
| 404 |
|
|
break;
|
| 405 |
|
|
xfoldcnst(I,i,/,divi);
|
| 406 |
|
|
break;
|
| 407 |
|
|
case DIV+U:
|
| 408 |
|
|
identity(r,l,U,u,1);
|
| 409 |
|
|
if (r->op == CNST+U && r->u.v.u == 0)
|
| 410 |
|
|
break;
|
| 411 |
|
|
if (r->op == CNST+U && (n = ispow2(r->u.v.u)) != 0)
|
| 412 |
|
|
return simplify(RSH, ty, l, cnsttree(inttype, (long)n));
|
| 413 |
|
|
foldcnst(U,u,/);
|
| 414 |
|
|
break;
|
| 415 |
|
|
case EQ+F:
|
| 416 |
|
|
cfoldcnst(F,d,==);
|
| 417 |
|
|
commute(r,l);
|
| 418 |
|
|
break;
|
| 419 |
|
|
case EQ+U:
|
| 420 |
|
|
cfoldcnst(U,u,==);
|
| 421 |
|
|
commute(r,l);
|
| 422 |
|
|
zerofield(EQ,U,u);
|
| 423 |
|
|
break;
|
| 424 |
|
|
case GE+F: cfoldcnst(F,d,>=); break;
|
| 425 |
|
|
case GE+I: cfoldcnst(I,i,>=); break;
|
| 426 |
|
|
case GE+U:
|
| 427 |
|
|
geu(l,r,1); /* l >= 0 => (l,1) */
|
| 428 |
|
|
cfoldcnst(U,u,>=);
|
| 429 |
|
|
if (l->op == CNST+U && l->u.v.u == 0) /* 0 >= r => r == 0 */
|
| 430 |
|
|
return eqtree(EQ, r, l);
|
| 431 |
|
|
break;
|
| 432 |
|
|
case GT+F: cfoldcnst(F,d, >); break;
|
| 433 |
|
|
case GT+I: cfoldcnst(I,i, >); break;
|
| 434 |
|
|
case GT+U:
|
| 435 |
|
|
geu(r,l,0); /* 0 > r => (r,0) */
|
| 436 |
|
|
cfoldcnst(U,u, >);
|
| 437 |
|
|
if (r->op == CNST+U && r->u.v.u == 0) /* l > 0 => l != 0 */
|
| 438 |
|
|
return eqtree(NE, l, r);
|
| 439 |
|
|
break;
|
| 440 |
|
|
case LE+F: cfoldcnst(F,d,<=); break;
|
| 441 |
|
|
case LE+I: cfoldcnst(I,i,<=); break;
|
| 442 |
|
|
case LE+U:
|
| 443 |
|
|
geu(r,l,1); /* 0 <= r => (r,1) */
|
| 444 |
|
|
cfoldcnst(U,u,<=);
|
| 445 |
|
|
if (r->op == CNST+U && r->u.v.u == 0) /* l <= 0 => l == 0 */
|
| 446 |
|
|
return eqtree(EQ, l, r);
|
| 447 |
|
|
break;
|
| 448 |
|
|
case LSH+I:
|
| 449 |
|
|
identity(r,l,I,i,0);
|
| 450 |
|
|
if (l->op == CNST+I && r->op == CNST+I
|
| 451 |
|
|
&& r->u.v.i >= 0 && r->u.v.i < 8*l->type->size
|
| 452 |
|
|
&& muli(l->u.v.i, 1<<r->u.v.i, ty->u.sym->u.limits.min.i, ty->u.sym->u.limits.max.i, needconst))
|
| 453 |
|
|
return cnsttree(ty, (long)(l->u.v.i<<r->u.v.i));
|
| 454 |
|
|
if (r->op == CNST+I && (r->u.v.i >= 8*ty->size || r->u.v.i < 0)) {
|
| 455 |
|
|
warning("shifting an `%t' by %d bits is undefined\n", ty, r->u.v.i);
|
| 456 |
|
|
break;
|
| 457 |
|
|
}
|
| 458 |
|
|
|
| 459 |
|
|
break;
|
| 460 |
|
|
case LSH+U:
|
| 461 |
|
|
identity(r,l,I,i,0);
|
| 462 |
|
|
sfoldcnst(<<);
|
| 463 |
|
|
if (r->op == CNST+I && (r->u.v.i >= 8*ty->size || r->u.v.i < 0)) {
|
| 464 |
|
|
warning("shifting an `%t' by %d bits is undefined\n", ty, r->u.v.i);
|
| 465 |
|
|
break;
|
| 466 |
|
|
}
|
| 467 |
|
|
|
| 468 |
|
|
break;
|
| 469 |
|
|
|
| 470 |
|
|
case LT+F: cfoldcnst(F,d, <); break;
|
| 471 |
|
|
case LT+I: cfoldcnst(I,i, <); break;
|
| 472 |
|
|
case LT+U:
|
| 473 |
|
|
geu(l,r,0); /* l < 0 => (l,0) */
|
| 474 |
|
|
cfoldcnst(U,u, <);
|
| 475 |
|
|
if (l->op == CNST+U && l->u.v.u == 0) /* 0 < r => r != 0 */
|
| 476 |
|
|
return eqtree(NE, r, l);
|
| 477 |
|
|
break;
|
| 478 |
|
|
case MOD+I:
|
| 479 |
|
|
if (r->op == CNST+I && r->u.v.i == 0
|
| 480 |
|
|
|| l->op == CNST+I && l->u.v.i == ty->u.sym->u.limits.min.i
|
| 481 |
|
|
&& r->op == CNST+I && r->u.v.i == -1)
|
| 482 |
|
|
break;
|
| 483 |
|
|
xfoldcnst(I,i,%,divi);
|
| 484 |
|
|
if (r->op == CNST+I && r->u.v.i == 1) /* l%1 => (l,0) */
|
| 485 |
|
|
return tree(RIGHT, ty, root(l), cnsttree(ty, 0L));
|
| 486 |
|
|
break;
|
| 487 |
|
|
case MOD+U:
|
| 488 |
|
|
if (r->op == CNST+U && ispow2(r->u.v.u)) /* l%2^n => l&(2^n-1) */
|
| 489 |
|
|
return bittree(BAND, l, cnsttree(ty, r->u.v.u - 1));
|
| 490 |
|
|
if (r->op == CNST+U && r->u.v.u == 0)
|
| 491 |
|
|
break;
|
| 492 |
|
|
foldcnst(U,u,%);
|
| 493 |
|
|
break;
|
| 494 |
|
|
case MUL+F:
|
| 495 |
|
|
xfoldcnst(F,d,*,muld);
|
| 496 |
|
|
commute(l,r);
|
| 497 |
|
|
break;
|
| 498 |
|
|
case MUL+I:
|
| 499 |
|
|
commute(l,r);
|
| 500 |
|
|
xfoldcnst(I,i,*,muli);
|
| 501 |
|
|
if (l->op == CNST+I && r->op == ADD+I && r->kids[1]->op == CNST+I)
|
| 502 |
|
|
/* c1*(x + c2) => c1*x + c1*c2 */
|
| 503 |
|
|
return simplify(ADD, ty, simplify(MUL, ty, l, r->kids[0]),
|
| 504 |
|
|
simplify(MUL, ty, l, r->kids[1]));
|
| 505 |
|
|
if (l->op == CNST+I && r->op == SUB+I && r->kids[1]->op == CNST+I)
|
| 506 |
|
|
/* c1*(x - c2) => c1*x - c1*c2 */
|
| 507 |
|
|
return simplify(SUB, ty, simplify(MUL, ty, l, r->kids[0]),
|
| 508 |
|
|
simplify(MUL, ty, l, r->kids[1]));
|
| 509 |
|
|
if (l->op == CNST+I && l->u.v.i > 0 && (n = ispow2(l->u.v.i)) != 0)
|
| 510 |
|
|
/* 2^n * r => r<<n */
|
| 511 |
|
|
return simplify(LSH, ty, r, cnsttree(inttype, (long)n));
|
| 512 |
|
|
identity(r,l,I,i,1);
|
| 513 |
|
|
break;
|
| 514 |
|
|
case NE+F:
|
| 515 |
|
|
cfoldcnst(F,d,!=);
|
| 516 |
|
|
commute(r,l);
|
| 517 |
|
|
break;
|
| 518 |
|
|
case NE+U:
|
| 519 |
|
|
cfoldcnst(U,u,!=);
|
| 520 |
|
|
commute(r,l);
|
| 521 |
|
|
zerofield(NE,U,u);
|
| 522 |
|
|
break;
|
| 523 |
|
|
case NEG+F:
|
| 524 |
|
|
ufoldcnst(F,cnsttree(ty, -l->u.v.d));
|
| 525 |
|
|
idempotent(NEG+F);
|
| 526 |
|
|
break;
|
| 527 |
|
|
case NEG+I:
|
| 528 |
|
|
if (l->op == CNST+I) {
|
| 529 |
|
|
if (needconst && l->u.v.i == ty->u.sym->u.limits.min.i)
|
| 530 |
|
|
warning("overflow in constant expression\n");
|
| 531 |
|
|
if (needconst || l->u.v.i != ty->u.sym->u.limits.min.i)
|
| 532 |
|
|
return cnsttree(ty, -l->u.v.i);
|
| 533 |
|
|
}
|
| 534 |
|
|
idempotent(NEG+I);
|
| 535 |
|
|
break;
|
| 536 |
|
|
case NOT+I:
|
| 537 |
|
|
op = NOT;
|
| 538 |
|
|
ufoldcnst(I,cnsttree(ty, !l->u.v.i));
|
| 539 |
|
|
break;
|
| 540 |
|
|
case RSH+I:
|
| 541 |
|
|
identity(r,l,I,i,0);
|
| 542 |
|
|
if (l->op == CNST+I && r->op == CNST+I
|
| 543 |
|
|
&& r->u.v.i >= 0 && r->u.v.i < 8*l->type->size) {
|
| 544 |
|
|
long n = l->u.v.i>>r->u.v.i;
|
| 545 |
|
|
if (l->u.v.i < 0)
|
| 546 |
|
|
n |= ~0UL<<(8*l->type->size - r->u.v.i);
|
| 547 |
|
|
return cnsttree(ty, n);
|
| 548 |
|
|
}
|
| 549 |
|
|
if (r->op == CNST+I && (r->u.v.i >= 8*ty->size || r->u.v.i < 0)) {
|
| 550 |
|
|
warning("shifting an `%t' by %d bits is undefined\n", ty, r->u.v.i);
|
| 551 |
|
|
break;
|
| 552 |
|
|
}
|
| 553 |
|
|
|
| 554 |
|
|
break;
|
| 555 |
|
|
case RSH+U:
|
| 556 |
|
|
identity(r,l,I,i,0);
|
| 557 |
|
|
sfoldcnst(>>);
|
| 558 |
|
|
if (r->op == CNST+I && (r->u.v.i >= 8*ty->size || r->u.v.i < 0)) {
|
| 559 |
|
|
warning("shifting an `%t' by %d bits is undefined\n", ty, r->u.v.i);
|
| 560 |
|
|
break;
|
| 561 |
|
|
}
|
| 562 |
|
|
|
| 563 |
|
|
break;
|
| 564 |
|
|
case SUB+F:
|
| 565 |
|
|
xfoldcnst(F,d,-,subd);
|
| 566 |
|
|
break;
|
| 567 |
|
|
case SUB+I:
|
| 568 |
|
|
xfoldcnst(I,i,-,subi);
|
| 569 |
|
|
identity(r,l,I,i,0);
|
| 570 |
|
|
break;
|
| 571 |
|
|
case SUB+U:
|
| 572 |
|
|
foldcnst(U,u,-);
|
| 573 |
|
|
identity(r,l,U,u,0);
|
| 574 |
|
|
break;
|
| 575 |
|
|
case SUB+P:
|
| 576 |
|
|
if (l->op == CNST+P && r->op == CNST+P)
|
| 577 |
|
|
return cnsttree(ty, (long)((char *)l->u.v.p - (char *)r->u.v.p));
|
| 578 |
|
|
if (r->op == CNST+I || r->op == CNST+U)
|
| 579 |
|
|
return simplify(ADD, ty, l,
|
| 580 |
|
|
cnsttree(inttype, r->op == CNST+I ? -r->u.v.i : -(long)r->u.v.u));
|
| 581 |
|
|
if (isaddrop(l->op) && r->op == ADD+I && r->kids[1]->op == CNST+I)
|
| 582 |
|
|
/* l - (x + c) => l-c - x */
|
| 583 |
|
|
return simplify(SUB, ty,
|
| 584 |
|
|
simplify(SUB, ty, l, r->kids[1]), r->kids[0]);
|
| 585 |
|
|
break;
|
| 586 |
|
|
default:assert(0);
|
| 587 |
|
|
}
|
| 588 |
|
|
return tree(op, ty, l, r);
|
| 589 |
|
|
}
|
| 590 |
|
|
/* ispow2 - if u > 1 && u == 2^n, return n, otherwise return 0 */
|
| 591 |
|
|
int ispow2(unsigned long u) {
|
| 592 |
|
|
int n;
|
| 593 |
|
|
|
| 594 |
|
|
if (u > 1 && (u&(u-1)) == 0)
|
| 595 |
|
|
for (n = 0; u; u >>= 1, n++)
|
| 596 |
|
|
if (u&1)
|
| 597 |
|
|
return n;
|
| 598 |
|
|
return 0;
|
| 599 |
|
|
}
|
| 600 |
|
|
|
