diff --git a/egs/gigaspeech/ASR/local/compile_hlg.py b/egs/gigaspeech/ASR/local/compile_hlg.py
deleted file mode 100755
index 712708c50..000000000
--- a/egs/gigaspeech/ASR/local/compile_hlg.py
+++ /dev/null
@@ -1,159 +0,0 @@
-#!/usr/bin/env python3
-# Copyright    2021  Xiaomi Corp.        (authors: Fangjun Kuang)
-#
-# See ../../../../LICENSE for clarification regarding multiple authors
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-
-"""
-This script takes as input lang_dir and generates HLG from
-
-    - H, the ctc topology, built from tokens contained in lang_dir/lexicon.txt
-    - L, the lexicon, built from lang_dir/L_disambig.pt
-
-        Caution: We use a lexicon that contains disambiguation symbols
-
-    - G, the LM, built from data/lm/G_4_gram.fst.txt
-
-The generated HLG is saved in $lang_dir/HLG.pt
-"""
-import argparse
-import logging
-from pathlib import Path
-
-import k2
-import torch
-
-from icefall.lexicon import Lexicon
-
-
-def get_args():
-    parser = argparse.ArgumentParser()
-    parser.add_argument(
-        "--lang-dir",
-        type=str,
-        help="""Input and output directory.
-        """,
-    )
-
-    return parser.parse_args()
-
-
-def compile_HLG(lang_dir: str) -> k2.Fsa:
-    """
-    Args:
-      lang_dir:
-        The language directory, e.g., data/lang_phone or data/lang_bpe_5000.
-
-    Return:
-      An FSA representing HLG.
-    """
-    lexicon = Lexicon(lang_dir)
-    max_token_id = max(lexicon.tokens)
-    logging.info(f"Building ctc_topo. max_token_id: {max_token_id}")
-    H = k2.ctc_topo(max_token_id)
-    L = k2.Fsa.from_dict(torch.load(f"{lang_dir}/L_disambig.pt"))
-
-    if Path("data/lm/G_4_gram.pt").is_file():
-        logging.info("Loading pre-compiled G_4_gram")
-        d = torch.load("data/lm/G_4_gram.pt")
-        G = k2.Fsa.from_dict(d)
-    else:
-        logging.info("Loading G_4_gram.fst.txt")
-        with open("data/lm/G_4_gram.fst.txt") as f:
-            G = k2.Fsa.from_openfst(f.read(), acceptor=False)
-            torch.save(G.as_dict(), "data/lm/G_4_gram.pt")
-
-    first_token_disambig_id = lexicon.token_table["#0"]
-    first_word_disambig_id = lexicon.word_table["#0"]
-
-    L = k2.arc_sort(L)
-    G = k2.arc_sort(G)
-
-    logging.info("Intersecting L and G")
-    LG = k2.compose(L, G)
-    logging.info(f"LG shape: {LG.shape}")
-
-    logging.info("Connecting LG")
-    LG = k2.connect(LG)
-    logging.info(f"LG shape after k2.connect: {LG.shape}")
-
-    logging.info(type(LG.aux_labels))
-    logging.info("Determinizing LG")
-
-    LG = k2.determinize(LG)
-    logging.info(type(LG.aux_labels))
-
-    logging.info("Connecting LG after k2.determinize")
-    LG = k2.connect(LG)
-
-    logging.info("Removing disambiguation symbols on LG")
-
-    LG.labels[LG.labels >= first_token_disambig_id] = 0
-    # See https://github.com/k2-fsa/k2/issues/874
-    # for why we need to set LG.properties to None
-    LG.__dict__["_properties"] = None
-
-    assert isinstance(LG.aux_labels, k2.RaggedTensor)
-    LG.aux_labels.values[LG.aux_labels.values >= first_word_disambig_id] = 0
-
-    LG = k2.remove_epsilon(LG)
-    logging.info(f"LG shape after k2.remove_epsilon: {LG.shape}")
-
-    LG = k2.connect(LG)
-    LG.aux_labels = LG.aux_labels.remove_values_eq(0)
-
-    logging.info("Arc sorting LG")
-    LG = k2.arc_sort(LG)
-
-    logging.info("Composing H and LG")
-    # CAUTION: The name of the inner_labels is fixed
-    # to `tokens`. If you want to change it, please
-    # also change other places in icefall that are using
-    # it.
-    HLG = k2.compose(H, LG, inner_labels="tokens")
-
-    logging.info("Connecting LG")
-    HLG = k2.connect(HLG)
-
-    logging.info("Arc sorting LG")
-    HLG = k2.arc_sort(HLG)
-    logging.info(f"HLG.shape: {HLG.shape}")
-
-    return HLG
-
-
-def main():
-    args = get_args()
-    lang_dir = Path(args.lang_dir)
-
-    if (lang_dir / "HLG.pt").is_file():
-        logging.info(f"{lang_dir}/HLG.pt already exists - skipping")
-        return
-
-    logging.info(f"Processing {lang_dir}")
-
-    HLG = compile_HLG(lang_dir)
-    logging.info(f"Saving HLG.pt to {lang_dir}")
-    torch.save(HLG.as_dict(), f"{lang_dir}/HLG.pt")
-
-
-if __name__ == "__main__":
-    formatter = (
-        "%(asctime)s %(levelname)s [%(filename)s:%(lineno)d] %(message)s"
-    )
-
-    logging.basicConfig(format=formatter, level=logging.INFO)
-
-    main()
diff --git a/egs/gigaspeech/ASR/local/compile_hlg.py b/egs/gigaspeech/ASR/local/compile_hlg.py
new file mode 120000
index 000000000..471aa7fb4
--- /dev/null
+++ b/egs/gigaspeech/ASR/local/compile_hlg.py
@@ -0,0 +1 @@
+../../../librispeech/ASR/local/compile_hlg.py
\ No newline at end of file
diff --git a/egs/gigaspeech/ASR/prepare.sh b/egs/gigaspeech/ASR/prepare.sh
index e18806994..559961507 100755
--- a/egs/gigaspeech/ASR/prepare.sh
+++ b/egs/gigaspeech/ASR/prepare.sh
@@ -23,6 +23,7 @@ num_splits=2000
 #      This directory contains the language model downloaded from
 #        https://huggingface.co/wgb14/gigaspeech_lm
 #
+#        - 3gram_pruned_1e7.arpa.gz
 #        - 4gram.arpa.gz
 #        - lexicon.txt
 #
@@ -63,6 +64,7 @@ if [ $stage -le -1 ] && [ $stop_stage -ge -1 ]; then
   # using: `sudo apt-get install git-lfs && git-lfs install`
   [ ! -e $dl_dir/lm ] && mkdir -p $dl_dir/lm
   git clone https://huggingface.co/wgb14/gigaspeech_lm $dl_dir/lm
+  gunzip -c $dl_dir/lm/3gram_pruned_1e7.arpa.gz > $dl_dir/lm/3gram_pruned_1e7.arpa
   gunzip -c $dl_dir/lm/4gram.arpa.gz > $dl_dir/lm/4gram.arpa
 fi
 
@@ -293,8 +295,17 @@ if [ $stage -le 12 ] && [ $stop_stage -ge 12 ]; then
 
   mkdir -p data/lm
 
-  if [ ! -f data/lm/G_4_gram.fst.txt ]; then
+  if [ ! -f data/lm/G_3_gram.fst.txt ]; then
     # It is used in building HLG
+    python3 -m kaldilm \
+      --read-symbol-table="data/lang_phone/words.txt" \
+      --disambig-symbol='#0' \
+      --max-order=3 \
+      $dl_dir/lm/3gram_pruned_1e7.arpa > data/lm/G_3_gram.fst.txt
+  fi
+
+  if [ ! -f data/lm/G_4_gram.fst.txt ]; then
+    # It is used for LM rescoring
     python3 -m kaldilm \
       --read-symbol-table="data/lang_phone/words.txt" \
       --disambig-symbol='#0' \