Chain jumpTrue() {
            if (tree == null) return Code.mergeChains(trueJumps, code.branch(opcode));
            // we should proceed further in -Xjcov mode only
            int startpc = code.curPc();
            Chain c = Code.mergeChains(trueJumps, code.branch(opcode));
            code.crt.put(tree, CRTable.CRT_BRANCH_TRUE, startpc, code.curPc());
            return c;
        }