Index: include/llvm/LTO/Config.h
===================================================================
--- include/llvm/LTO/Config.h
+++ include/llvm/LTO/Config.h
@@ -46,6 +46,16 @@
   unsigned OptLevel = 2;
   bool DisableVerify = false;
 
+  enum EmitIRType {
+    EIRT_CodeGen, /// Do CodeGen and emit CGFileType
+    EIRT_LL,      /// Emit human-readable LLVM assembly
+    EIRT_BC,      /// Emit LLVM bitcode files
+    EIRT_Nothing, /// Don't emit anything (benchmarking mode)
+  };
+
+  /// Type of IR file to output, defaults to none (do codegen).
+  EmitIRType IROutputType = EIRT_CodeGen;
+
   /// Disable entirely the optimizer, including importing for ThinLTO
   bool CodeGenOnly = false;
 
Index: lib/LTO/LTOBackend.cpp
===================================================================
--- lib/LTO/LTOBackend.cpp
+++ lib/LTO/LTOBackend.cpp
@@ -21,6 +21,8 @@
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/Bitcode/BitcodeReader.h"
 #include "llvm/Bitcode/BitcodeWriter.h"
+#include "llvm/Bitcode/BitcodeWriterPass.h"
+#include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/PassManager.h"
 #include "llvm/IR/Verifier.h"
@@ -269,11 +271,32 @@
   if (Conf.PreCodeGenModuleHook && !Conf.PreCodeGenModuleHook(Task, Mod))
     return;
 
-  auto Stream = AddStream(Task);
-  legacy::PassManager CodeGenPasses;
-  if (TM->addPassesToEmitFile(CodeGenPasses, *Stream->OS, Conf.CGFileType))
-    report_fatal_error("Failed to setup codegen");
-  CodeGenPasses.run(Mod);
+  switch (Conf.IROutputType) {
+  case Config::EIRT_Nothing:
+    break;
+
+  case Config::EIRT_BC: {
+    auto Stream = AddStream(Task);
+    legacy::PassManager PerModulePasses;
+    PerModulePasses.add(createBitcodeWriterPass(*Stream->OS));
+    PerModulePasses.run(Mod);
+  } break;
+
+  case Config::EIRT_LL: {
+    auto Stream = AddStream(Task);
+    legacy::PassManager PerModulePasses;
+    PerModulePasses.add(createPrintModulePass(*Stream->OS));
+    PerModulePasses.run(Mod);
+  } break;
+
+  case Config::EIRT_CodeGen: {
+    auto Stream = AddStream(Task);
+    legacy::PassManager CodeGenPasses;
+    if (TM->addPassesToEmitFile(CodeGenPasses, *Stream->OS, Conf.CGFileType))
+      report_fatal_error("Failed to setup codegen");
+    CodeGenPasses.run(Mod);
+  } break;
+  }
 }
 
 void splitCodeGen(Config &C, TargetMachine *TM, AddStreamFn AddStream,