diff --git a/llvm/test/Reduce/Inputs/remove-args.py b/llvm/test/Reduce/Inputs/remove-args.py
--- a/llvm/test/Reduce/Inputs/remove-args.py
+++ b/llvm/test/Reduce/Inputs/remove-args.py
@@ -3,17 +3,10 @@
 import sys
 
 UsedArgumentPresent = False
-# So ReduceFunctions pass doesn't remove anything
-FunctionCount = 0
 
 input = open(sys.argv[1], "r")
 for line in input:
   if "%used" in line:
-    UsedArgumentPresent = True
-  if "define" in line:
-    FunctionCount += 1
+    sys.exit(0) # Interesting!
 
-if UsedArgumentPresent and FunctionCount == 3:
-  sys.exit(0) # Interesting!
-else:
-  sys.exit(1)
+sys.exit(1)
diff --git a/llvm/test/Reduce/remove-args.ll b/llvm/test/Reduce/remove-args.ll
--- a/llvm/test/Reduce/remove-args.ll
+++ b/llvm/test/Reduce/remove-args.ll
@@ -1,7 +1,7 @@
 ; Test that llvm-reduce can remove uninteresting function arguments from function definitions as well as their calls.
 ; Note: This pass also removes InstAllocs of uninteresting args
 ;
-; RUN: llvm-reduce --test %p/Inputs/remove-args.py %s
+; RUN: llvm-reduce --test %p/Inputs/remove-args.py %s --run-only args
 ; RUN: cat reduced.ll | FileCheck %s
 ; REQUIRES: plugins
 
diff --git a/llvm/test/Reduce/remove-funcs.ll b/llvm/test/Reduce/remove-funcs.ll
--- a/llvm/test/Reduce/remove-funcs.ll
+++ b/llvm/test/Reduce/remove-funcs.ll
@@ -1,7 +1,7 @@
 ; Test that llvm-reduce can remove uninteresting functions as well as
 ; their InstCalls.
 ;
-; RUN: llvm-reduce --test %p/Inputs/remove-funcs.py %s
+; RUN: llvm-reduce --test %p/Inputs/remove-funcs.py %s --run-only funcs
 ; RUN: cat reduced.ll | FileCheck %s
 ; REQUIRES: plugins
 
diff --git a/llvm/test/Reduce/remove-global-vars.ll b/llvm/test/Reduce/remove-global-vars.ll
--- a/llvm/test/Reduce/remove-global-vars.ll
+++ b/llvm/test/Reduce/remove-global-vars.ll
@@ -1,7 +1,7 @@
 ; Test that llvm-reduce can remove uninteresting Global Variables as well as
 ; their direct uses.
 ;
-; RUN: llvm-reduce --test %p/Inputs/remove-global-vars.py %s
+; RUN: llvm-reduce --test %p/Inputs/remove-global-vars.py %s --run-only globals
 ; RUN: cat reduced.ll | FileCheck %s
 ; REQUIRES: plugins
 
diff --git a/llvm/test/Reduce/remove-metadata.ll b/llvm/test/Reduce/remove-metadata.ll
--- a/llvm/test/Reduce/remove-metadata.ll
+++ b/llvm/test/Reduce/remove-metadata.ll
@@ -1,7 +1,7 @@
 ; Test that llvm-reduce can remove uninteresting metadata from an IR file.
 ; The Metadata pass erases named & unnamed metadata nodes, as well as debug functions.
 ;
-; RUN: llvm-reduce --test %p/Inputs/remove-metadata.py %s
+; RUN: llvm-reduce --test %p/Inputs/remove-metadata.py %s --run-only metadata
 ; RUN: cat reduced.ll | FileCheck %s
 ; REQUIRES: plugins
 
diff --git a/llvm/tools/llvm-reduce/DeltaManager.h b/llvm/tools/llvm-reduce/DeltaManager.h
--- a/llvm/tools/llvm-reduce/DeltaManager.h
+++ b/llvm/tools/llvm-reduce/DeltaManager.h
@@ -20,7 +20,6 @@
 
 namespace llvm {
 
-// TODO: Add CLI option to run only specified Passes (for unit tests)
 inline void runDeltaPasses(TestRunner &Tester) {
   reduceFunctionsDeltaPass(Tester);
   reduceGlobalsDeltaPass(Tester);
@@ -29,4 +28,18 @@
   // TODO: Implement the remaining Delta Passes
 }
 
+inline void runSpecifiedDeltaPasses(TestRunner &Tester,
+                                    const std::vector<std::string> &Passes) {
+  for (auto &Pass : Passes) {
+    if (Pass == "funcs")
+      reduceFunctionsDeltaPass(Tester);
+    else if (Pass == "globals")
+      reduceGlobalsDeltaPass(Tester);
+    else if (Pass == "metadata")
+      reduceMetadataDeltaPass(Tester);
+    else if (Pass == "args")
+      reduceArgumentsDeltaPass(Tester);
+  }
+}
+
 } // namespace llvm
diff --git a/llvm/tools/llvm-reduce/llvm-reduce.cpp b/llvm/tools/llvm-reduce/llvm-reduce.cpp
--- a/llvm/tools/llvm-reduce/llvm-reduce.cpp
+++ b/llvm/tools/llvm-reduce/llvm-reduce.cpp
@@ -53,11 +53,24 @@
                  cl::desc("WARNING: This option will replace your input file"
                           "with the reduced version!"));
 
-static cl::opt<bool>
-    RunOnlySpecifiedPasses("run-only", 
-                           cl::desc("option used for testing purposes,"
-                                    "runs only the specified delta passes"),
-                           cl::Hidden);
+static cl::opt<std::string>
+    SpecifiedPasses("run-only",
+                    cl::desc("option used for testing purposes,"
+                             "runs only the specified delta passes"),
+                    cl::Hidden);
+
+static std::vector<std::string> parseDeltaPassNames(std::string PassNames) {
+  std::vector<std::string> DeltaPasses;
+  if (PassNames.empty())
+    return DeltaPasses;
+
+  SmallVector<StringRef, 8> Deltas;
+  StringRef(PassNames).split(Deltas, ',', -1, false);
+  for (auto &D : Deltas)
+    DeltaPasses.push_back(D);
+
+  return DeltaPasses;
+}
 
 // Parses IR into a Module and verifies it
 static std::unique_ptr<Module> parseInputFile(StringRef Filename,
@@ -90,8 +103,14 @@
   TestRunner Tester(TestFilename, TestArguments, InputFilename);
   Tester.setProgram(std::move(OriginalProgram));
 
-  // Try to reduce code
-  runDeltaPasses(Tester);
+  // No passes specified, run all of them
+  if (SpecifiedPasses.empty())
+    runDeltaPasses(Tester);
+  else {
+    std::vector<std::string> DeltaPasses = parseDeltaPassNames(SpecifiedPasses);
+    runSpecifiedDeltaPasses(Tester, DeltaPasses);
+  }
+
   StringRef ReducedFilename = sys::path::filename(Tester.getReducedFilepath());
 
   if (ReducedFilename == sys::path::filename(InputFilename)) {