diff --git a/clang/include/clang/Basic/CodeGenOptions.def b/clang/include/clang/Basic/CodeGenOptions.def
--- a/clang/include/clang/Basic/CodeGenOptions.def
+++ b/clang/include/clang/Basic/CodeGenOptions.def
@@ -61,8 +61,7 @@
 CODEGENOPT(DisableO0ImplyOptNone , 1, 0) ///< Don't annonate function with optnone at O0
 CODEGENOPT(ExperimentalStrictFloatingPoint, 1, 0) ///< Enables the new, experimental
                                                   ///< strict floating point.
-CODEGENOPT(ExperimentalNewPassManager, 1, 0) ///< Enables the new, experimental
-                                             ///< pass manager.
+CODEGENOPT(LegacyPassManager, 1, 0) ///< Use the legacy pass manager.
 CODEGENOPT(DebugPassManager, 1, 0) ///< Prints debug information for the new
                                    ///< pass manager.
 CODEGENOPT(DisableRedZone    , 1, 0) ///< Set when -mno-red-zone is enabled.
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -1351,9 +1351,13 @@
   HelpText<"Enables the global instruction selector">;
 def fexperimental_isel : Flag<["-"], "fexperimental-isel">, Group<f_clang_Group>,
   Alias<fglobal_isel>;
-defm experimental_new_pass_manager : BooleanMarshalledFFlag<"experimental-new-pass-manager", "CodeGenOpts.ExperimentalNewPassManager",
-  "static_cast<unsigned>(LLVM_ENABLE_NEW_PASS_MANAGER)", "Enables an experimental new pass manager in LLVM.",
-  "Disables an experimental new pass manager in LLVM.">, Group<f_clang_Group>, Flags<[CC1Option]>;
+defm legacy_pass_manager : BooleanMarshalledFFlag<"legacy-pass-manager", "CodeGenOpts.LegacyPassManager",
+  "static_cast<unsigned>(LLVM_ENABLE_NEW_PASS_MANAGER)", "Use the legacy pass manager in LLVM",
+  "Use the new pass manager in LLVM">, Group<f_clang_Group>, Flags<[CC1Option]>;
+def fexperimental_new_pass_manager : Flag<["-"], "fexperimental-new-pass-manager">,
+  Group<f_clang_Group>, Flags<[CC1Option]>, Alias<fno_legacy_pass_manager>;
+def fno_experimental_new_pass_manager : Flag<["-"], "fno-experimental-new-pass-manager">,
+  Group<f_clang_Group>, Flags<[CC1Option]>, Alias<flegacy_pass_manager>;
 def fexperimental_strict_floating_point : Flag<["-"], "fexperimental-strict-floating-point">,
   Group<f_clang_Group>, Flags<[CC1Option]>,
   HelpText<"Enables experimental strict floating point in LLVM.">,
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -1482,7 +1482,7 @@
   }
 
   Conf.ProfileRemapping = std::move(ProfileRemapping);
-  Conf.UseNewPM = CGOpts.ExperimentalNewPassManager;
+  Conf.UseNewPM = !CGOpts.LegacyPassManager;
   Conf.DebugPassManager = CGOpts.DebugPassManager;
   Conf.RemarksWithHotness = CGOpts.DiagnosticsWithHotness;
   Conf.RemarksFilename = CGOpts.OptRecordFile;
@@ -1572,7 +1572,7 @@
 
   EmitAssemblyHelper AsmHelper(Diags, HeaderOpts, CGOpts, TOpts, LOpts, M);
 
-  if (CGOpts.ExperimentalNewPassManager)
+  if (!CGOpts.LegacyPassManager)
     AsmHelper.EmitAssemblyWithNewPassManager(Action, std::move(OS));
   else
     AsmHelper.EmitAssembly(Action, std::move(OS));
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -5848,8 +5848,8 @@
                    false))
     CmdArgs.push_back("-fmodules-debuginfo");
 
-  Args.AddLastArg(CmdArgs, options::OPT_fexperimental_new_pass_manager,
-                  options::OPT_fno_experimental_new_pass_manager);
+  Args.AddLastArg(CmdArgs, options::OPT_flegacy_pass_manager,
+                  options::OPT_fno_legacy_pass_manager);
 
   ObjCRuntime Runtime = AddObjCRuntimeArgs(Args, Inputs, CmdArgs, rewriteKind);
   RenderObjCOptions(TC, D, RawTriple, Args, Runtime, rewriteKind != RK_None,
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -595,11 +595,13 @@
                                          Path));
   }
 
-  // Need this flag to turn on new pass manager via Gold plugin.
-  if (Args.hasFlag(options::OPT_fexperimental_new_pass_manager,
-                   options::OPT_fno_experimental_new_pass_manager,
-                   /* Default */ LLVM_ENABLE_NEW_PASS_MANAGER)) {
-    CmdArgs.push_back("-plugin-opt=new-pass-manager");
+  // Pass an option to enable/disable the new pass manager.
+  if (auto *A = Args.getLastArg(options::OPT_flegacy_pass_manager,
+                                options::OPT_fno_legacy_pass_manager)) {
+    if (A->getOption().matches(options::OPT_flegacy_pass_manager))
+      CmdArgs.push_back("-plugin-opt=legacy-pass-manager");
+    else
+      CmdArgs.push_back("-plugin-opt=new-pass-manager");
   }
 
   // Setup statistics file output.
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1006,10 +1006,10 @@
     setPGOUseInstrumentor(Opts, Opts.ProfileInstrumentUsePath);
   Opts.ProfileRemappingFile =
       std::string(Args.getLastArgValue(OPT_fprofile_remapping_file_EQ));
-  if (!Opts.ProfileRemappingFile.empty() && !Opts.ExperimentalNewPassManager) {
+  if (!Opts.ProfileRemappingFile.empty() && Opts.LegacyPassManager) {
     Diags.Report(diag::err_drv_argument_only_allowed_with)
-      << Args.getLastArg(OPT_fprofile_remapping_file_EQ)->getAsString(Args)
-      << "-fexperimental-new-pass-manager";
+        << Args.getLastArg(OPT_fprofile_remapping_file_EQ)->getAsString(Args)
+        << "-fno-legacy-pass-manager";
   }
 
   Opts.CoverageMapping =
@@ -1051,9 +1051,9 @@
 
     // -ftime-report= is only for new pass manager.
     if (A->getOption().getID() == OPT_ftime_report_EQ) {
-      if (!Opts.ExperimentalNewPassManager)
+      if (Opts.LegacyPassManager)
         Diags.Report(diag::err_drv_argument_only_allowed_with)
-            << A->getAsString(Args) << "-fexperimental-new-pass-manager";
+            << A->getAsString(Args) << "-fno-legacy-pass-manager";
 
       StringRef Val = A->getValue();
       if (Val == "per-pass")
diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c
--- a/clang/test/Driver/clang_f_opts.c
+++ b/clang/test/Driver/clang_f_opts.c
@@ -466,14 +466,6 @@
 // CHECK-WCHAR2-NOT: -fwchar-type=int
 // DELIMITERS: {{^ *"}}
 
-// RUN: %clang -### -fno-experimental-new-pass-manager -fexperimental-new-pass-manager %s 2>&1 | FileCheck --check-prefix=CHECK-PM --check-prefix=CHECK-NEW-PM %s
-// RUN: %clang -### -fexperimental-new-pass-manager -fno-experimental-new-pass-manager %s 2>&1 | FileCheck --check-prefix=CHECK-PM --check-prefix=CHECK-NO-NEW-PM %s
-// CHECK-PM-NOT: argument unused
-// CHECK-NEW-PM: -fexperimental-new-pass-manager
-// CHECK-NEW-PM-NOT: -fno-experimental-new-pass-manager
-// CHECK-NO-NEW-PM: -fno-experimental-new-pass-manager
-// CHECK-NO-NEW-PM-NOT: -fexperimental-new-pass-manager
-
 // RUN: %clang -### -S -fstrict-return %s 2>&1 | FileCheck -check-prefix=CHECK-STRICT-RETURN %s
 // RUN: %clang -### -S -fno-strict-return %s 2>&1 | FileCheck -check-prefix=CHECK-NO-STRICT-RETURN %s
 // CHECK-STRICT-RETURN-NOT: "-fno-strict-return"
diff --git a/clang/test/Driver/flegacy-pass-manager.c b/clang/test/Driver/flegacy-pass-manager.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Driver/flegacy-pass-manager.c
@@ -0,0 +1,30 @@
+// RUN: %clang -### -c -flegacy-pass-manager -fno-legacy-pass-manager %s 2>&1 | FileCheck --check-prefixes=NOWARN,NEW %s
+// RUN: %clang -### -c -fno-legacy-pass-manager -flegacy-pass-manager %s 2>&1 | FileCheck --check-prefixes=NOWARN,LEGACY %s
+
+/// -f[no-]experimental-new-pass-manager are legacy aliases when the new PM was still experimental.
+// RUN: %clang -### -c -fno-experimental-new-pass-manager -fexperimental-new-pass-manager %s 2>&1 | FileCheck --check-prefixes=NOWARN,NEW %s
+// RUN: %clang -### -c -fexperimental-new-pass-manager -fno-experimental-new-pass-manager %s 2>&1 | FileCheck --check-prefixes=NOWARN,LEGACY %s
+
+// NOWARN-NOT: warning: argument unused
+
+// NEW:        -fno-legacy-pass-manager
+// NEW-NOT:    -flegacy-pass-manager
+
+// LEGACY:     -flegacy-pass-manager
+// LEGACY-NOT: -fno-legacy-pass-manager
+
+/// For full/Thin LTO, -fno-legacy-pass-manager passes -plugin-opt=new-pass-manager to the linker (which may not be LLD).
+// RUN: %clang -### -target x86_64-linux -flto -fno-legacy-pass-manager %s 2>&1 | FileCheck --check-prefix=LTO_NEW %s
+// RUN: %clang -### -target x86_64-linux -flto=thin -fexperimental-new-pass-manager %s 2>&1 | FileCheck --check-prefix=LTO_NEW %s
+
+// LTO_NEW:    "-plugin-opt=new-pass-manager"
+
+// RUN: %clang -### -target x86_64-linux -flto -flegacy-pass-manager %s 2>&1 | FileCheck --check-prefix=LTO_LEGACY %s
+// RUN: %clang -### -target x86_64-linux -flto=thin -fno-experimental-new-pass-manager %s 2>&1 | FileCheck --check-prefix=LTO_LEGACY %s
+
+// LTO_LEGACY: "-plugin-opt=legacy-pass-manager"
+
+// RUN: %clang -### -target x86_64-linux -flto %s 2>&1 | FileCheck --check-prefix=DEFAULT %s
+//
+// DEFAULT-NOT: "-plugin-opt=new-pass-manager"
+// DEFAULT-NOT: "-plugin-opt=legacy-pass-manager"
diff --git a/clang/test/Driver/gold-lto-new-pass-man.c b/clang/test/Driver/gold-lto-new-pass-man.c
deleted file mode 100644
--- a/clang/test/Driver/gold-lto-new-pass-man.c
+++ /dev/null
@@ -1,7 +0,0 @@
-// RUN: touch %t.o
-//
-// RUN: %clang -target ppc64le-unknown-linux -### %t.o -flto 2>&1 \
-// RUN:     -Wl,-plugin-opt=foo -O3 \
-// RUN:     -fexperimental-new-pass-manager \
-// RUN:     | FileCheck %s
-// CHECK: "-plugin-opt=new-pass-manager"