/*
** Try to "constant-fold" an operation; return 1 iff successful
*/
static int constfolding (FuncState *fs, int op, expdesc *e1, expdesc *e2) {
TValue v1, v2, res;
if (!tonumeral(e1, &v1) || !tonumeral(e2, &v2) || !validop(op, &v1, &v2))
return 0; /* non-numeric operands or not safe to fold */
luaO_arith(fs->ls->L, op, &v1, &v2, &res);
if (ttisinteger(&res)) {
e1->k = VKINT;
e1->u.ival = ivalue(&res);
}
else {
lua_Number n = fltvalue(&res);
if (luai_numisnan(n) || isminuszero(n))
return 0; /* folds neither NaN nor -0 */
e1->k = VKFLT;
e1->u.nval = n;
}
return 1;
}
/*
** Both NaN and -0.0 should not go to the constant table, as they have
** problems with the hashing. (NaN is not a valid key, -0.0 collides
** with +0.0.)
*/
static int luaK_numberK (FuncState *fs, lua_Number r) {
TValue o;
lua_assert(!luai_numisnan(r) && !isminuszero(r));
setfltvalue(&o, r);
return addk(fs, &o, &o);
}
