Function codeeq

src/lcode.cpp:1808–1849

** Emit code for equality comparisons ('==', '~='). ** 'e1' was already put as RK by 'luaK_infix'. */

** 'e1' was already put as RK by 'luaK_infix'.
*/
static void codeeq (FuncState *fs, BinOpr opr, expdesc *e1, expdesc *e2) {
  int r1, r2;
  int im;
  int isfloat = 0;  /* not needed here, but kept for symmetry */
  OpCode op;
  if (e1->k != VNONRELOC && e1->k != VSAFECALL) {
    lua_assert(vkisconst(e1->k) && !hasjumps(e1));
    swapexps(e1, e2);
  }
  if (vkisconst(e1->k) && vkisconst(e2->k) && !hasjumps(e1) && !hasjumps(e2)
      && (e1->k != VKINT || e2->k != VKFLT) && (e1->k != VKFLT || e2->k != VKINT)  /* don't optimize comparisons between VKINT and VKFLT */
  ) {
    bool eq = false;
    if (e1->k == e2->k) {
      switch (e1->k) {
      default: eq = true; break;
      case VKFLT: eq = (e1->u.nval == e2->u.nval); break;
      case VKINT: eq = (e1->u.ival == e2->u.ival); break;
      case VKSTR: eq = (e1->u.strval == e2->u.strval); break;
      case VCONST: eq = (e1->u.info == e2->u.info); break;
      }
    }
    e1->k = ((eq ^ (opr != OPR_EQ)) ? VTRUE : VFALSE);
    return;
  }
  r1 = luaK_exp2anyreg(fs, e1);  /* 1st expression must be in register */
  if (isSCnumber(e2, &im, &isfloat)) {
    op = OP_EQI;
    r2 = im;  /* immediate operand */
  }
  else if (exp2RK(fs, e2)) {  /* 2nd expression is constant? */
    op = OP_EQK;
    r2 = e2->u.info;  /* constant index */
  }
  else {
    op = OP_EQ;  /* will compare two registers */
    r2 = luaK_exp2anyreg(fs, e2);
  }
  freeexps(fs, e1, e2);
  e1->u.pc = condjump(fs, op, r1, r2, isfloat, (opr == OPR_EQ));
  e1->k = VJMP;
}


/*