Index: llvm/unittests/CodeGen/GlobalISel/CMakeLists.txt
===================================================================
--- llvm/unittests/CodeGen/GlobalISel/CMakeLists.txt
+++ llvm/unittests/CodeGen/GlobalISel/CMakeLists.txt
@@ -19,4 +19,5 @@
   GISelMITest.cpp
   PatternMatchTest.cpp
   KnownBitsTest.cpp
+  GISelUtilsTest.cpp
   )
Index: llvm/unittests/CodeGen/GlobalISel/GISelUtilsTest.cpp
===================================================================
--- /dev/null
+++ llvm/unittests/CodeGen/GlobalISel/GISelUtilsTest.cpp
@@ -0,0 +1,117 @@
+//===- GISelUtilsTest.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/GlobalISel/Utils.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+constexpr LLT S1 = LLT::scalar(1);
+constexpr LLT S16 = LLT::scalar(16);
+constexpr LLT S32 = LLT::scalar(32);
+constexpr LLT S64 = LLT::scalar(64);
+constexpr LLT P0 = LLT::pointer(0, 64);
+constexpr LLT P1 = LLT::pointer(1, 32);
+
+constexpr LLT V2S16 = LLT::vector(2, 16);
+constexpr LLT V4S16 = LLT::vector(4, 16);
+
+constexpr LLT V2S32 = LLT::vector(2, 32);
+constexpr LLT V3S32 = LLT::vector(3, 32);
+constexpr LLT V4S32 = LLT::vector(4, 32);
+constexpr LLT V6S32 = LLT::vector(6, 32);
+
+constexpr LLT V2P0 = LLT::vector(2, P0);
+constexpr LLT V3P0 = LLT::vector(3, P0);
+constexpr LLT V4P0 = LLT::vector(4, P0);
+constexpr LLT V6P0 = LLT::vector(6, P0);
+
+TEST(GISelUtilsTest, getGCDType) {
+  EXPECT_EQ(S1, getGCDType(S1, S1));
+  EXPECT_EQ(S32, getGCDType(S32, S32));
+  EXPECT_EQ(S1, getGCDType(S1, S32));
+  EXPECT_EQ(S1, getGCDType(S32, S1));
+  EXPECT_EQ(S16, getGCDType(S16, S32));
+  EXPECT_EQ(S16, getGCDType(S32, S16));
+
+  EXPECT_EQ(V2S32, getGCDType(V2S32, V2S32));
+  EXPECT_EQ(S32, getGCDType(V3S32, V2S32));
+  EXPECT_EQ(S32, getGCDType(V2S32, V3S32));
+
+  EXPECT_EQ(V2S16, getGCDType(V4S16, V2S16));
+  EXPECT_EQ(V2S16, getGCDType(V2S16, V4S16));
+
+  EXPECT_EQ(V2S32, getGCDType(V4S32, V2S32));
+  EXPECT_EQ(V2S32, getGCDType(V2S32, V4S32));
+
+
+  EXPECT_EQ(S16, getGCDType(P0, S16));
+  EXPECT_EQ(S16, getGCDType(S16, P0));
+
+  EXPECT_EQ(S32, getGCDType(P0, S32));
+  EXPECT_EQ(S32, getGCDType(S32, P0));
+
+  EXPECT_EQ(S64, getGCDType(P0, S64));
+  EXPECT_EQ(S64, getGCDType(S64, P0));
+
+  EXPECT_EQ(S32, getGCDType(P0, P1));
+  EXPECT_EQ(S32, getGCDType(P1, P0));
+
+  EXPECT_EQ(P0, getGCDType(V3P0, V2P0));
+  EXPECT_EQ(P0, getGCDType(V2P0, V3P0));
+}
+
+TEST(GISelUtilsTest, getLCMType) {
+  EXPECT_EQ(S1, getLCMType(S1, S1));
+  EXPECT_EQ(S32, getLCMType(S32, S1));
+  EXPECT_EQ(S32, getLCMType(S1, S32));
+  EXPECT_EQ(S32, getLCMType(S32, S32));
+
+  EXPECT_EQ(S32, getLCMType(S32, S16));
+  EXPECT_EQ(S32, getLCMType(S16, S32));
+
+  EXPECT_EQ(S64, getLCMType(S64, P0));
+  EXPECT_EQ(S64, getLCMType(P0, S64));
+
+  EXPECT_EQ(S64, getLCMType(S32, P0));
+  EXPECT_EQ(S64, getLCMType(P0, S32));
+
+  EXPECT_EQ(S32, getLCMType(S32, P1));
+  EXPECT_EQ(S32, getLCMType(P1, S32));
+  EXPECT_EQ(S64, getLCMType(P0, P0));
+  EXPECT_EQ(S32, getLCMType(P1, P1));
+
+  EXPECT_EQ(S64, getLCMType(P0, P1));
+  EXPECT_EQ(S64, getLCMType(P1, P0));
+
+  EXPECT_EQ(V2S32, getLCMType(V2S32, V2S32));
+  EXPECT_EQ(V2S32, getLCMType(V2S32, S32));
+  EXPECT_EQ(V2S32, getLCMType(S32, V2S32));
+  EXPECT_EQ(V2S32, getLCMType(V2S32, V2S32));
+  EXPECT_EQ(V6S32, getLCMType(V2S32, V3S32));
+  EXPECT_EQ(V6S32, getLCMType(V3S32, V2S32));
+  EXPECT_EQ(LLT::vector(12, S32), getLCMType(V4S32, V3S32));
+  EXPECT_EQ(LLT::vector(12, S32), getLCMType(V3S32, V4S32));
+
+  EXPECT_EQ(V2P0, getLCMType(V2P0, V2P0));
+  EXPECT_EQ(V2P0, getLCMType(V2P0, P0));
+  EXPECT_EQ(V2P0, getLCMType(P0, V2P0));
+  EXPECT_EQ(V2P0, getLCMType(V2P0, V2P0));
+  EXPECT_EQ(V6P0, getLCMType(V2P0, V3P0));
+  EXPECT_EQ(V6P0, getLCMType(V3P0, V2P0));
+  EXPECT_EQ(LLT::vector(12, P0), getLCMType(V4P0, V3P0));
+  EXPECT_EQ(LLT::vector(12, P0), getLCMType(V3P0, V4P0));
+
+  EXPECT_EQ(V2S32, getLCMType(V2S32, S64));
+
+  // FIXME
+  //EXPECT_EQ(S64, getLCMType(S64, V2S32));
+}
+
+}