Revert "[PeepholeOptimizer] Look through PHIs to find additional register sources"

Reported to Broke some internal tests: PR24303

This reverts commit r243486.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243540 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetInstrInfo.h

@@ -1276,33 +1276,6 @@ private:
   unsigned CallFrameSetupOpcode, CallFrameDestroyOpcode;
 };
 
-/// \brief Provide DenseMapInfo for TargetInstrInfo::RegSubRegPair.
-template<>
-struct DenseMapInfo<TargetInstrInfo::RegSubRegPair> {
-  typedef DenseMapInfo<unsigned> RegInfo;
-
-  static inline TargetInstrInfo::RegSubRegPair getEmptyKey() {
-    return TargetInstrInfo::RegSubRegPair(RegInfo::getEmptyKey(),
-                         RegInfo::getEmptyKey());
-  }
-  static inline TargetInstrInfo::RegSubRegPair getTombstoneKey() {
-    return TargetInstrInfo::RegSubRegPair(RegInfo::getTombstoneKey(),
-                         RegInfo::getTombstoneKey());
-  }
-  /// \brief Reuse getHashValue implementation from
-  /// std::pair<unsigned, unsigned>.
-  static unsigned getHashValue(const TargetInstrInfo::RegSubRegPair &Val) {
-    std::pair<unsigned, unsigned> PairVal =
-        std::make_pair(Val.Reg, Val.SubReg);
-    return DenseMapInfo<std::pair<unsigned, unsigned>>::getHashValue(PairVal);
-  }
-  static bool isEqual(const TargetInstrInfo::RegSubRegPair &LHS,
-                      const TargetInstrInfo::RegSubRegPair &RHS) {
-    return RegInfo::isEqual(LHS.Reg, RHS.Reg) &&
-           RegInfo::isEqual(LHS.SubReg, RHS.SubReg);
-  }
-};
-
 } // End llvm namespace
 
 #endif