diff --git a/clang-tools-extra/clangd/CompileCommands.cpp b/clang-tools-extra/clangd/CompileCommands.cpp
index ba21e81d3fb525..ffc66303c9fc4c 100644
--- a/clang-tools-extra/clangd/CompileCommands.cpp
+++ b/clang-tools-extra/clangd/CompileCommands.cpp
@@ -9,14 +9,11 @@
 #include "CompileCommands.h"
 #include "Config.h"
 #include "support/Logger.h"
-#include "support/Trace.h"
 #include "clang/Driver/Options.h"
 #include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Tooling/ArgumentsAdjusters.h"
 #include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Option/ArgList.h"
 #include "llvm/Option/Option.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/Debug.h"
@@ -191,33 +188,11 @@ CommandMangler CommandMangler::detect() {
   return Result;
 }
 
-CommandMangler CommandMangler::forTests() { return CommandMangler(); }
+CommandMangler CommandMangler::forTests() {
+  return CommandMangler();
+}
 
 void CommandMangler::adjust(std::vector<std::string> &Cmd) const {
-  trace::Span S("AdjustCompileFlags");
-  auto &OptTable = clang::driver::getDriverOptTable();
-  // OriginalArgs needs to outlive ArgList.
-  llvm::SmallVector<const char *, 16> OriginalArgs;
-  OriginalArgs.reserve(Cmd.size());
-  for (const std::string &S : Cmd)
-    OriginalArgs.push_back(S.c_str());
-  // ParseArgs propagates missig arg/opt counts on error, but preserves
-  // everything it could parse in ArgList. So we just ignore those counts.
-  unsigned IgnoredCount;
-  auto ArgList = OptTable.ParseArgs(OriginalArgs, IgnoredCount, IgnoredCount);
-
-  // Move the inputs to the end, separated via `--` from flags. This ensures
-  // modifications done in the following steps apply in more cases (like setting
-  // -x, which only affects inputs that come after it).
-  if (!ArgList.hasArgNoClaim(driver::options::OPT__DASH_DASH)) {
-    // In theory there might be more than one input, but clangd can't deal with
-    // them anyway.
-    if (auto *Input = ArgList.getLastArg(driver::options::OPT_INPUT)) {
-      Cmd.insert(Cmd.end(), {"--", Input->getAsString(ArgList)});
-      Cmd.erase(Cmd.begin() + Input->getIndex());
-    }
-  }
-
   for (auto &Edit : Config::current().CompileFlags.Edits)
     Edit(Cmd);
 
@@ -240,7 +215,7 @@ void CommandMangler::adjust(std::vector<std::string> &Cmd) const {
 
   // Don't set `-isysroot` if it is already set or if `--sysroot` is set.
   // `--sysroot` is a superset of the `-isysroot` argument.
-  if (Sysroot && !Has("--sysroot") && !Has("-isysroot")) {
+  if (Sysroot && !Has("-isysroot") && !Has("--sysroot")) {
     ToAppend.push_back("-isysroot");
     ToAppend.push_back(*Sysroot);
   }
diff --git a/clang-tools-extra/clangd/test/did-change-configuration-params.test b/clang-tools-extra/clangd/test/did-change-configuration-params.test
index e90e26c0d3a7ab..19d41d0812e232 100644
--- a/clang-tools-extra/clangd/test/did-change-configuration-params.test
+++ b/clang-tools-extra/clangd/test/did-change-configuration-params.test
@@ -48,7 +48,7 @@
 #
 # ERR: ASTWorker building file {{.*}}foo.c version 0 with command
 # ERR: [{{.*}}clangd-test2]
-# ERR: clang -c -Wall -Werror {{.*}} -- foo.c
+# ERR: clang -c foo.c -Wall -Werror
 ---
 {"jsonrpc":"2.0","id":5,"method":"shutdown"}
 ---
diff --git a/clang-tools-extra/clangd/unittests/BackgroundIndexTests.cpp b/clang-tools-extra/clangd/unittests/BackgroundIndexTests.cpp
index 79da2f059a8c29..de8ff2b4a14e17 100644
--- a/clang-tools-extra/clangd/unittests/BackgroundIndexTests.cpp
+++ b/clang-tools-extra/clangd/unittests/BackgroundIndexTests.cpp
@@ -133,9 +133,8 @@ TEST_F(BackgroundIndexTest, Config) {
   Opts.ContextProvider = [](PathRef P) {
     Config C;
     if (P.endswith("foo.cpp"))
-      C.CompileFlags.Edits.push_back([](std::vector<std::string> &Argv) {
-        Argv = tooling::getInsertArgumentAdjuster("-Done=two")(Argv, "");
-      });
+      C.CompileFlags.Edits.push_back(
+          [](std::vector<std::string> &Argv) { Argv.push_back("-Done=two"); });
     if (P.endswith("baz.cpp"))
       C.Index.Background = Config::BackgroundPolicy::Skip;
     return Context::current().derive(Config::Key, std::move(C));
diff --git a/clang-tools-extra/clangd/unittests/CompileCommandsTests.cpp b/clang-tools-extra/clangd/unittests/CompileCommandsTests.cpp
index 11f0b409dfecaf..f5727305b465c4 100644
--- a/clang-tools-extra/clangd/unittests/CompileCommandsTests.cpp
+++ b/clang-tools-extra/clangd/unittests/CompileCommandsTests.cpp
@@ -11,7 +11,6 @@
 #include "TestFS.h"
 #include "support/Context.h"
 
-#include "clang/Tooling/ArgumentsAdjusters.h"
 #include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/FileSystem.h"
@@ -166,15 +165,13 @@ TEST(CommandMangler, ConfigEdits) {
         for (char &C : Arg)
           C = llvm::toUpper(C);
     });
-    Cfg.CompileFlags.Edits.push_back([](std::vector<std::string> &Argv) {
-      Argv = tooling::getInsertArgumentAdjuster("--hello")(Argv, "");
-    });
+    Cfg.CompileFlags.Edits.push_back(
+        [](std::vector<std::string> &Argv) { Argv.push_back("--hello"); });
     WithContextValue WithConfig(Config::Key, std::move(Cfg));
     Mangler.adjust(Cmd);
   }
-  // Edits are applied in given order and before other mangling and they always
-  // go before filename.
-  EXPECT_THAT(Cmd, ElementsAre(_, "--hello", "--", "FOO.CC"));
+  // Edits are applied in given order and before other mangling.
+  EXPECT_THAT(Cmd, ElementsAre(_, "FOO.CC", "--hello"));
 }
 
 static std::string strip(llvm::StringRef Arg, llvm::StringRef Argv) {
@@ -338,8 +335,9 @@ TEST(ArgStripperTest, OrderDependent) {
 }
 
 TEST(PrintArgvTest, All) {
-  std::vector<llvm::StringRef> Args = {"one",      "two",    "thr ee",
-                                       "f\"o\"ur", "fi\\ve", "$"};
+  std::vector<llvm::StringRef> Args = {
+      "one", "two", "thr ee", "f\"o\"ur", "fi\\ve", "$"
+  };
   const char *Expected = R"(one two "thr ee" "f\"o\"ur" "fi\\ve" $)";
   EXPECT_EQ(Expected, printArgv(Args));
 }