[GISel]: Fix broken matcher for hasOneUse

[aditya_nandakumar]

Summary

Fix build breakage with code that was never instantiated.

[aditya_nandakumar]

363424

include/llvm/CodeGen/GlobalISel/MIPatternMatch.h

bool mi_match(Reg R, MachineRegisterInfo &MRI, Pattern &&P) {
   return P.match(MRI, R);
 }
 
 // TODO: Extend for N use.
 template <typename SubPatternT> struct OneUse_match {
   SubPatternT SubPat;
   OneUse_match(const SubPatternT &SP) : SubPat(SP) {}
 
-  template <typename OpTy>
-  bool match(const MachineRegisterInfo &MRI, unsigned Reg) {
+  bool match(MachineRegisterInfo &MRI, unsigned Reg) {
     return MRI.hasOneUse(Reg) && SubPat.match(MRI, Reg);
   }
 };
 
 template <typename SubPat>
 inline OneUse_match<SubPat> m_OneUse(const SubPat &SP) {
   return SP;
 }

unittests/CodeGen/GlobalISel/PatternMatchTest.cpp

TEST(PatternMatchInstr, MatchCombinators) {
   EXPECT_EQ(Src1, Copies[1]);
 
   // Match a case where none of the predicates hold true.
   match = mi_match(
       MIBAdd->getOperand(0).getReg(), MRI,
       m_any_of(m_SpecificType(LLT::scalar(16)), m_GSub(m_Reg(), m_Reg())));
   EXPECT_FALSE(match);
 }
+
+TEST(PatternMatchInstr, MatchMiscellaneous) {
+  LLVMContext Context;
+  std::unique_ptr<LLVMTargetMachine> TM = createTargetMachine();
+  if (!TM)
+    return;
+  auto ModuleMMIPair = createDummyModule(Context, *TM, "");
+  MachineFunction *MF =
+      getMFFromMMI(ModuleMMIPair.first.get(), ModuleMMIPair.second.get());
+  SmallVector<unsigned, 4> Copies;
+  collectCopies(Copies, MF);
+  MachineBasicBlock *EntryMBB = &*MF->begin();
+  MachineIRBuilder B(*MF);
+  MachineRegisterInfo &MRI = MF->getRegInfo();
+  B.setInsertPt(*EntryMBB, EntryMBB->end());
+  LLT s64 = LLT::scalar(64);
+  auto MIBAdd = B.buildAdd(s64, Copies[0], Copies[1]);
+  // Make multiple uses of this add.
+  B.buildCast(LLT::pointer(0, 32), MIBAdd);
+  B.buildCast(LLT::pointer(1, 32), MIBAdd);
+  bool match = mi_match(MIBAdd.getReg(0), MRI, m_GAdd(m_Reg(), m_Reg()));
+  EXPECT_TRUE(match);
+  match = mi_match(MIBAdd.getReg(0), MRI, m_OneUse(m_GAdd(m_Reg(), m_Reg())));
+  EXPECT_FALSE(match);
+}
 } // namespace
 
 int main(int argc, char **argv) {
   ::testing::InitGoogleTest(&argc, argv);
   initLLVM();
   return RUN_ALL_TESTS();
 }