diff --git a/lld/COFF/Config.h b/lld/COFF/Config.h
index 1c338cc63fa87..8e86d5493b3d0 100644
--- a/lld/COFF/Config.h
+++ b/lld/COFF/Config.h
@@ -102,6 +102,12 @@ enum class ICFLevel {
         // behavior.
 };
 
+enum class LTOKind{
+  Default, // Any LTO mode without Unified LTO. The default mode.
+  UnifiedRegular, // Regular LTO, with Unified LTO enabled.
+  UnifiedThin // ThinLTO, with Unified LTO enabled.
+};
+
 // Global configuration.
 struct Configuration {
   enum ManifestKind { Default, SideBySide, Embed, No };
@@ -317,6 +323,8 @@ struct Configuration {
   bool writeCheckSum = false;
   EmitKind emit = EmitKind::Obj;
   bool allowDuplicateWeak = false;
+  LTOKind ltoKind;
+  bool useDefaultPipeline = false;
 };
 
 } // namespace lld::coff
diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
index 5613c2e6993a5..44cb85f694b1e 100644
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -1882,6 +1882,15 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
         if (s.getAsInteger(10, config->ltoPartitions) ||
             config->ltoPartitions == 0)
           error("/opt:lldltopartitions: invalid partition count: " + s);
+      } else if (s.consume_front("lldltobackend=")) {
+        config->ltoKind = StringSwitch<LTOKind>(s)
+                              .Case("default", LTOKind::Default)
+                              .Case("unifiedthin", LTOKind::UnifiedThin)
+                              .Case("unifiedregular", LTOKind::UnifiedRegular)
+                              .Default(LTOKind::Default);
+
+      } else if (s.equals("ltodefaultpipeline")) {
+        config->useDefaultPipeline = true;
       } else if (s != "lbr" && s != "nolbr")
         error("/opt: unknown option: " + s);
     }
diff --git a/lld/COFF/LTO.cpp b/lld/COFF/LTO.cpp
index 7df9319112136..20942e6e55d3d 100644
--- a/lld/COFF/LTO.cpp
+++ b/lld/COFF/LTO.cpp
@@ -47,6 +47,19 @@ std::string BitcodeCompiler::getThinLTOOutputFile(StringRef path) {
   return lto::getThinLTOOutputFile(path, ctx.config.thinLTOPrefixReplaceOld,
                                    ctx.config.thinLTOPrefixReplaceNew);
 }
+static lto::LTO::LTOKind toLTOKind(LTOKind kind) {
+  switch (kind) {
+  case LTOKind::Default: {
+    return lto::LTO::LTOK_Default;
+  }
+  case LTOKind::UnifiedRegular: {
+    return lto::LTO::LTOK_UnifiedRegular;
+  }
+  case LTOKind::UnifiedThin: {
+    return lto::LTO::LTOK_UnifiedThin;
+  }
+  }
+}
 
 lto::Config BitcodeCompiler::createConfig() {
   lto::Config c;
@@ -88,6 +101,7 @@ lto::Config BitcodeCompiler::createConfig() {
   c.PGOWarnMismatch = ctx.config.ltoPGOWarnMismatch;
   c.TimeTraceEnabled = ctx.config.timeTraceEnabled;
   c.TimeTraceGranularity = ctx.config.timeTraceGranularity;
+  c.UseDefaultPipeline = ctx.config.useDefaultPipeline;
 
   if (ctx.config.emit == EmitKind::LLVM) {
     c.PostInternalizeModuleHook = [this](size_t task, const Module &m) {
@@ -126,8 +140,9 @@ BitcodeCompiler::BitcodeCompiler(COFFLinkerContext &c) : ctx(c) {
         llvm::heavyweight_hardware_concurrency(ctx.config.thinLTOJobs));
   }
 
+  lto::LTO::LTOKind kind = toLTOKind(ctx.config.ltoKind);
   ltoObj = std::make_unique<lto::LTO>(createConfig(), backend,
-                                      ctx.config.ltoPartitions);
+                                      ctx.config.ltoPartitions, kind);
 }
 
 BitcodeCompiler::~BitcodeCompiler() = default;