diff --git a/include/llvm/CodeGen/GlobalISel/MIPatternMatch.h b/include/llvm/CodeGen/GlobalISel/MIPatternMatch.h
index 336eba7f979..797f5e542fb 100644
--- a/include/llvm/CodeGen/GlobalISel/MIPatternMatch.h
+++ b/include/llvm/CodeGen/GlobalISel/MIPatternMatch.h
@@ -43,8 +43,8 @@ inline OneUse_match<SubPat> m_OneUse(const SubPat &SP) {
 }
 
 struct ConstantMatch {
-  uint64_t &CR;
-  ConstantMatch(uint64_t &C) : CR(C) {}
+  int64_t &CR;
+  ConstantMatch(int64_t &C) : CR(C) {}
   bool match(const MachineRegisterInfo &MRI, unsigned Reg) {
     if (auto MaybeCst = getConstantVRegVal(Reg, MRI)) {
       CR = *MaybeCst;
@@ -54,7 +54,7 @@ struct ConstantMatch {
   }
 };
 
-inline ConstantMatch m_ICst(uint64_t &Cst) { return ConstantMatch(Cst); }
+inline ConstantMatch m_ICst(int64_t &Cst) { return ConstantMatch(Cst); }
 
 // TODO: Rework this for different kinds of MachineOperand.
 // Currently assumes the Src for a match is a register.
diff --git a/unittests/CodeGen/GlobalISel/PatternMatchTest.cpp b/unittests/CodeGen/GlobalISel/PatternMatchTest.cpp
index d402d0b1e11..1084db78180 100644
--- a/unittests/CodeGen/GlobalISel/PatternMatchTest.cpp
+++ b/unittests/CodeGen/GlobalISel/PatternMatchTest.cpp
@@ -134,10 +134,10 @@ TEST(PatternMatchInstr, MatchIntConstant) {
   MachineRegisterInfo &MRI = MF->getRegInfo();
   B.setInsertPt(*EntryMBB, EntryMBB->end());
   auto MIBCst = B.buildConstant(LLT::scalar(64), 42);
-  uint64_t Cst;
+  int64_t Cst;
   bool match = mi_match(MIBCst->getOperand(0).getReg(), MRI, m_ICst(Cst));
   ASSERT_TRUE(match);
-  ASSERT_EQ(Cst, (uint64_t)42);
+  ASSERT_EQ(Cst, 42);
 }
 
 TEST(PatternMatchInstr, MatchBinaryOp) {
@@ -189,11 +189,11 @@ TEST(PatternMatchInstr, MatchBinaryOp) {
   auto MIBMul2 = B.buildMul(s64, Copies[0], B.buildConstant(s64, 42));
   // Try to match MUL(Cst, Reg) on src of MUL(Reg, Cst) to validate
   // commutativity.
-  uint64_t Cst;
+  int64_t Cst;
   match = mi_match(MIBMul2->getOperand(0).getReg(), MRI,
                    m_GMul(m_ICst(Cst), m_Reg(Src0)));
   ASSERT_TRUE(match);
-  ASSERT_EQ(Cst, (uint64_t)42);
+  ASSERT_EQ(Cst, 42);
   ASSERT_EQ(Src0, Copies[0]);
 
   // Make sure commutative doesn't work with something like SUB.
@@ -208,7 +208,7 @@ TEST(PatternMatchInstr, MatchBinaryOp) {
   match = mi_match(MIBFMul->getOperand(0).getReg(), MRI,
                    m_GFMul(m_ICst(Cst), m_Reg(Src0)));
   ASSERT_TRUE(match);
-  ASSERT_EQ(Cst, (uint64_t)42);
+  ASSERT_EQ(Cst, 42);
   ASSERT_EQ(Src0, Copies[0]);
 
   // Build AND %0, %1