diff --git a/llvm/test/tools/llvm-reduce/custom-delta-passes.ll b/llvm/test/tools/llvm-reduce/custom-delta-passes.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-reduce/custom-delta-passes.ll
@@ -0,0 +1,20 @@
+; RUN: llvm-reduce --delta-passes=module-inline-asm --test FileCheck --test-arg --check-prefixes=CHECK-INTERESTINGNESS --test-arg %s --test-arg --input-file %s -o %t
+; RUN: FileCheck --check-prefix=CHECK-NOCHANGE %s < %t
+; RUN: llvm-reduce --delta-passes=function-bodies --test FileCheck --test-arg --check-prefixes=CHECK-INTERESTINGNESS --test-arg %s --test-arg --input-file %s -o %t
+; RUN: FileCheck --check-prefix=CHECK-CHANGE %s < %t
+; RUN: llvm-reduce --delta-passes=function-bodies,module-inline-asm --test FileCheck --test-arg --check-prefixes=CHECK-INTERESTINGNESS --test-arg %s --test-arg --input-file %s -o %t
+; RUN: FileCheck --check-prefix=CHECK-CHANGE %s < %t
+
+; RUN: not llvm-reduce --delta-passes=foo --test FileCheck --test-arg --check-prefixes=CHECK-INTERESTINGNESS --test-arg %s --test-arg --input-file %s -o %t 2>&1 | FileCheck %s --check-prefix=ERROR
+; RUN: not llvm-reduce --delta-passes='function-bodies;module-inline-asm' --test FileCheck --test-arg --check-prefixes=CHECK-INTERESTINGNESS --test-arg %s --test-arg --input-file %s -o %t 2>&1 | FileCheck %s --check-prefix=ERROR
+
+; CHECK-INTERESTINGNESS: @f
+
+; CHECK-NOCHANGE: define {{.*}} @f
+; CHECK-CHANGE: declare {{.*}} @f
+
+; ERROR: unknown
+
+define void @f() {
+  ret void
+}
diff --git a/llvm/tools/llvm-reduce/DeltaManager.cpp b/llvm/tools/llvm-reduce/DeltaManager.cpp
--- a/llvm/tools/llvm-reduce/DeltaManager.cpp
+++ b/llvm/tools/llvm-reduce/DeltaManager.cpp
@@ -28,11 +28,15 @@
 #include "deltas/ReduceModuleInlineAsm.h"
 #include "deltas/ReduceOperandBundles.h"
 #include "deltas/ReduceSpecialGlobals.h"
+#include "llvm/Support/CommandLine.h"
 
-namespace llvm {
+using namespace llvm;
 
-// TODO: Add CLI option to run only specified Passes (for unit tests)
-void runDeltaPasses(TestRunner &Tester) {
+static cl::opt<std::string>
+    DeltaPasses("delta-passes",
+                cl::desc("Delta passes to run, separated by commas"));
+
+static void runAllDeltaPasses(TestRunner &Tester) {
   reduceSpecialGlobalsDeltaPass(Tester);
   reduceAliasesDeltaPass(Tester);
   reduceFunctionBodiesDeltaPass(Tester);
@@ -49,4 +53,51 @@
   reduceModuleInlineAsmDeltaPass(Tester);
   // TODO: Implement the remaining Delta Passes
 }
-} // namespace llvm
+
+static void runDeltaPassName(TestRunner &Tester, StringRef PassName) {
+  if (PassName == "special-globals") {
+    reduceSpecialGlobalsDeltaPass(Tester);
+  } else if (PassName == "aliases") {
+    reduceAliasesDeltaPass(Tester);
+  } else if (PassName == "function-bodies") {
+    reduceFunctionBodiesDeltaPass(Tester);
+  } else if (PassName == "functions") {
+    reduceFunctionsDeltaPass(Tester);
+  } else if (PassName == "basic-blocks") {
+    reduceBasicBlocksDeltaPass(Tester);
+  } else if (PassName == "global-values") {
+    reduceGlobalValuesDeltaPass(Tester);
+  } else if (PassName == "global-initializers") {
+    reduceGlobalsInitializersDeltaPass(Tester);
+  } else if (PassName == "global-variables") {
+    reduceGlobalsDeltaPass(Tester);
+  } else if (PassName == "metadata") {
+    reduceMetadataDeltaPass(Tester);
+  } else if (PassName == "arguments") {
+    reduceArgumentsDeltaPass(Tester);
+  } else if (PassName == "instructions") {
+    reduceInstructionsDeltaPass(Tester);
+  } else if (PassName == "operand-bundles") {
+    reduceOperandBundesDeltaPass(Tester);
+  } else if (PassName == "attributes") {
+    reduceAttributesDeltaPass(Tester);
+  } else if (PassName == "module-inline-asm") {
+    reduceModuleInlineAsmDeltaPass(Tester);
+  } else {
+    errs() << "unknown pass \"" << PassName << "\"";
+    exit(1);
+  }
+}
+
+void llvm::runDeltaPasses(TestRunner &Tester) {
+  if (DeltaPasses.empty()) {
+    runAllDeltaPasses(Tester);
+  } else {
+    StringRef Passes = DeltaPasses;
+    while (!Passes.empty()) {
+      auto Split = Passes.split(",");
+      runDeltaPassName(Tester, Split.first);
+      Passes = Split.second;
+    }
+  }
+}