Function patchtestreg

depends/lua/src/lcode.c:195–207

** Patch destination register for a TESTSET instruction. ** If instruction in position 'node' is not a TESTSET, return 0 ("fails"). ** Otherwise, if 'reg' is not 'NO_REG', set it as the destination ** register. Otherwise, change instruction to a simple 'TEST' (produces ** no register value) */

** no register value)
*/
static int patchtestreg (FuncState *fs, int node, int reg) {
  Instruction *i = getjumpcontrol(fs, node);
  if (GET_OPCODE(*i) != OP_TESTSET)
    return 0;  /* cannot patch other instructions */
  if (reg != NO_REG && reg != GETARG_B(*i))
    SETARG_A(*i, reg);
  else {
     /* no register to put value or register already has the value;
        change instruction to simple test */
    *i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));
  }
  return 1;
}


/*