diff --git a/llvm/docs/TestingGuide.rst b/llvm/docs/TestingGuide.rst
index 6ab33383e929..f2c953a6221f 100644
--- a/llvm/docs/TestingGuide.rst
+++ b/llvm/docs/TestingGuide.rst
@@ -328,6 +328,9 @@ assertions:
   update_test_checks.py
   opt
 
+  update_llubi_test_checks.py
+  llubi
+
 Precommit workflow for tests
 ----------------------------
 
diff --git a/llvm/test/tools/llubi/main.ll b/llvm/test/tools/llubi/main.ll
index c10824621018..d1e91312314e 100644
--- a/llvm/test/tools/llubi/main.ll
+++ b/llvm/test/tools/llubi/main.ll
@@ -1,3 +1,4 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
 ; RUN: llubi --verbose < %s 2>&1 | FileCheck %s
 
 define i32 @main(i32 %argc, ptr %argv) {
@@ -5,7 +6,7 @@ define i32 @main(i32 %argc, ptr %argv) {
 }
 
 ; CHECK: Entering function: main
-; CHECK:   i32 %argc = i32 1
-; CHECK:   ptr %argv = ptr 0x8 [argv]
-; CHECK:   ret i32 0
-; CHECK: Exiting function: main
+; CHECK-NEXT:   i32 %argc = i32 1
+; CHECK-NEXT:   ptr %argv = ptr 0x8 [argv]
+; CHECK-NEXT:   ret i32 0
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/main2.ll b/llvm/test/tools/llubi/main2.ll
index 58c5744bb090..0752f6335418 100644
--- a/llvm/test/tools/llubi/main2.ll
+++ b/llvm/test/tools/llubi/main2.ll
@@ -1,3 +1,4 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
 ; RUN: llubi --verbose < %s 2>&1 | FileCheck %s
 
 define i32 @main() {
@@ -5,5 +6,5 @@ define i32 @main() {
 }
 
 ; CHECK: Entering function: main
-; CHECK:   ret i32 0
-; CHECK: Exiting function: main
+; CHECK-NEXT:   ret i32 0
+; CHECK-NEXT: Exiting function: main
diff --git a/llvm/test/tools/llubi/poison.ll b/llvm/test/tools/llubi/poison.ll
index cf3b69d1aeb7..9d98b7f75e86 100644
--- a/llvm/test/tools/llubi/poison.ll
+++ b/llvm/test/tools/llubi/poison.ll
@@ -1,11 +1,12 @@
+; NOTE: Assertions have been autogenerated by utils/update_llubi_test_checks.py UTC_ARGS: --version 6
 ; RUN: not llubi --verbose < %s 2>&1 | FileCheck %s
 
 define i32 @main(i32 %argc, ptr %argv) {
   ret i32 poison
 }
 ; CHECK: Entering function: main
-; CHECK:   i32 %argc = i32 1
-; CHECK:   ptr %argv = ptr 0x8 [argv]
-; CHECK:   ret i32 poison
-; CHECK: Exiting function: main
-; CHECK: error: Execution of function 'main' resulted in poison return value.
+; CHECK-NEXT:   i32 %argc = i32 1
+; CHECK-NEXT:   ptr %argv = ptr 0x8 [argv]
+; CHECK-NEXT:   ret i32 poison
+; CHECK-NEXT: Exiting function: main
+; CHECK-NEXT: error: Execution of function 'main' resulted in poison return value.
diff --git a/llvm/utils/UpdateTestChecks/common.py b/llvm/utils/UpdateTestChecks/common.py
index 9cca0a7ad5d3..60ee18f5e4fc 100644
--- a/llvm/utils/UpdateTestChecks/common.py
+++ b/llvm/utils/UpdateTestChecks/common.py
@@ -2723,6 +2723,7 @@ def get_autogennote_suffix(parser, args):
             "tool_binary",
             "opt_binary",
             "llc_binary",
+            "llubi_binary",
             "clang",
             "opt",
             "llvm_bin",
diff --git a/llvm/utils/update_llubi_test_checks.py b/llvm/utils/update_llubi_test_checks.py
new file mode 100755
index 000000000000..6b2600069835
--- /dev/null
+++ b/llvm/utils/update_llubi_test_checks.py
@@ -0,0 +1,135 @@
+#!/usr/bin/env python3
+# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+"""A test case update script.
+
+This script is a utility to update LLVM 'llubi' based test cases with new
+FileCheck patterns.
+"""
+
+from __future__ import print_function
+
+from sys import stderr
+from traceback import print_exc
+import argparse
+import os
+import subprocess
+import sys
+
+from UpdateTestChecks import common
+
+
+# Invoke the tool that is being tested.
+def invoke_tool(exe, cmd_args, ir, check_rc):
+    with open(ir) as ir_file:
+        substitutions = common.getSubstitutions(ir)
+        stdout = subprocess.run(
+            exe + " " + common.applySubstitutions(cmd_args, substitutions),
+            shell=True,
+            stdin=ir_file,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.STDOUT,
+            check=check_rc,
+        ).stdout.decode()
+    # Fix line endings to unix CR style.
+    return stdout.replace("\r\n", "\n")
+
+
+def update_test(ti: common.TestInfo):
+    if len(ti.run_lines) == 0:
+        common.warn("No RUN lines found in test: " + ti.path)
+        return
+    if len(ti.run_lines) > 1:
+        common.warn("Multiple RUN lines found in test: " + ti.path)
+        common.warn("Only the first RUN line will be processed.")
+
+    l = ti.run_lines[0]
+    if "|" not in l:
+        common.warn("Skipping unparsable RUN line: " + l)
+        return
+
+    commands = [cmd.strip() for cmd in l.split("|")]
+    assert len(commands) == 2
+    llubi_cmd = commands[-2]
+    filecheck_cmd = commands[-1]
+    args = llubi_cmd.split(" ")
+    llubi_tool = args[0]
+    check_rc = True
+    if len(args) > 1 and args[0] == "not":
+        llubi_tool = args[1]
+        check_rc = False
+
+    common.verify_filecheck_prefixes(filecheck_cmd)
+
+    if llubi_tool != "llubi":
+        common.warn("Skipping non-llubi RUN line: " + l)
+        return
+
+    if not filecheck_cmd.startswith("FileCheck "):
+        common.warn("Skipping non-FileChecked RUN line: " + l)
+        return
+
+    llubi_args = llubi_cmd[llubi_cmd.index(llubi_tool) + len(llubi_tool) :].strip()
+    llubi_args = llubi_args.replace("< %s", "").replace("%s", "").strip()
+    prefixes = common.get_check_prefixes(filecheck_cmd)
+
+    common.debug("Extracted llubi cmd:", llubi_tool, llubi_args)
+    common.debug("Extracted FileCheck prefixes:", str(prefixes))
+    prefix_set = set([prefix for prefix in prefixes])
+
+    raw_tool_output = invoke_tool(
+        ti.args.llubi_binary or llubi_tool,
+        llubi_args,
+        ti.path,
+        check_rc=check_rc,
+    )
+    if ti.args.llubi_binary:
+        raw_tool_output = raw_tool_output.replace(ti.args.llubi_binary, llubi_tool)
+
+    output_lines = []
+    common.dump_input_lines(output_lines, ti, prefix_set, ";")
+    tool_output_lines = raw_tool_output.splitlines()
+    if len(tool_output_lines) == 0:
+        common.warn("No output from llubi.")
+    else:
+        output_lines.append("; CHECK: " + tool_output_lines[0])
+        output_lines.extend(["; CHECK-NEXT: " + line for line in tool_output_lines[1:]])
+
+    common.debug("Writing %d lines to %s..." % (len(output_lines), ti.path))
+    with open(ti.path, "wb") as f:
+        f.writelines(["{}\n".format(l).encode("utf-8") for l in output_lines])
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument(
+        "--llubi-binary",
+        default=None,
+        help='The "llubi" binary to use to generate the test case',
+    )
+    parser.add_argument(
+        "--tool",
+        default=None,
+        help="Treat the given tool name as an llubi-like tool for which check lines should be generated",
+    )
+    parser.add_argument("tests", nargs="+")
+    initial_args = common.parse_commandline_args(parser)
+
+    script_name = os.path.basename(__file__)
+
+    returncode = 0
+    for ti in common.itertests(
+        initial_args.tests, parser, script_name="utils/" + script_name
+    ):
+        try:
+            update_test(ti)
+        except Exception as e:
+            stderr.write(f"Error: Failed to update test {ti.path}\n")
+            print_exc()
+            returncode = 1
+    return returncode
+
+
+if __name__ == "__main__":
+    sys.exit(main())