Index: llvm/trunk/include/llvm/CodeGen/MachineMemOperand.h
===================================================================
--- llvm/trunk/include/llvm/CodeGen/MachineMemOperand.h
+++ llvm/trunk/include/llvm/CodeGen/MachineMemOperand.h
@@ -89,32 +89,27 @@
 ///
 class MachineMemOperand {
 public:
-  // This is the number of bits we need to represent flags.
-  static LLVM_CONSTEXPR unsigned MOMaxBits = 8;
-
-  // Target hints allow target passes to annotate memory operations.
-  static LLVM_CONSTEXPR unsigned MOTargetStartBit = 5;
-  static LLVM_CONSTEXPR unsigned MOTargetNumBits = 3;
-
   /// Flags values. These may be or'd together.
   enum Flags : uint16_t {
     // No flags set.
     MONone = 0,
     /// The memory access reads data.
-    MOLoad = 1,
+    MOLoad = 1u << 0,
     /// The memory access writes data.
-    MOStore = 2,
+    MOStore = 1u << 1,
     /// The memory access is volatile.
-    MOVolatile = 4,
+    MOVolatile = 1u << 2,
     /// The memory access is non-temporal.
-    MONonTemporal = 8,
+    MONonTemporal = 1u << 3,
     /// The memory access is invariant.
-    MOInvariant = 16,
+    MOInvariant = 1u << 4,
 
-    // Maximum MemOperandFlag value (inclusive).
-    MOMaxFlag = (1 << MOMaxBits) - 1,
+    // Reserved for use by target-specific passes.
+    MOTargetFlag1 = 1u << 5,
+    MOTargetFlag2 = 1u << 6,
+    MOTargetFlag3 = 1u << 7,
 
-    LLVM_MARK_AS_BITMASK_ENUM(MOMaxFlag)
+    LLVM_MARK_AS_BITMASK_ENUM(/* LargestFlag = */ MOTargetFlag3)
   };
 
 private:
Index: llvm/trunk/lib/CodeGen/MachineInstr.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/MachineInstr.cpp
+++ llvm/trunk/lib/CodeGen/MachineInstr.cpp
@@ -503,8 +503,6 @@
                                      const MDNode *Ranges)
     : PtrInfo(ptrinfo), Size(s), FlagVals(f), BaseAlignLog2(Log2_32(a) + 1),
       AAInfo(AAInfo), Ranges(Ranges) {
-  assert(MOMaxFlag == (1 << MOMaxBits) - 1 &&
-         "MOMaxFlag and MOMaxBits have fallen out of sync.");
   assert((PtrInfo.V.isNull() || PtrInfo.V.is<const PseudoSourceValue*>() ||
           isa<PointerType>(PtrInfo.V.get<const Value*>()->getType())) &&
          "invalid pointer value");
Index: llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.h
===================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.h
+++ llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.h
@@ -28,12 +28,6 @@
 class AArch64TargetMachine;
 
 class AArch64InstrInfo : public AArch64GenInstrInfo {
-  // Reserve bits in the MachineMemOperand target hint flags, starting at 1.
-  // They will be shifted into MOTargetHintStart when accessed.
-  enum TargetMemOperandFlags {
-    MOSuppressPair = 1
-  };
-
   const AArch64RegisterInfo RI;
   const AArch64Subtarget &Subtarget;
 
Index: llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.cpp
===================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -29,6 +29,9 @@
 #define GET_INSTRINFO_CTOR_DTOR
 #include "AArch64GenInstrInfo.inc"
 
+static constexpr MachineMemOperand::Flags MOSuppressPair =
+    MachineMemOperand::MOTargetFlag1;
+
 AArch64InstrInfo::AArch64InstrInfo(const AArch64Subtarget &STI)
     : AArch64GenInstrInfo(AArch64::ADJCALLSTACKDOWN, AArch64::ADJCALLSTACKUP),
       RI(STI.getTargetTriple()), Subtarget(STI) {}
@@ -1449,27 +1452,16 @@
 
 /// Check all MachineMemOperands for a hint to suppress pairing.
 bool AArch64InstrInfo::isLdStPairSuppressed(const MachineInstr &MI) const {
-  static_assert(MOSuppressPair < (1 << MachineMemOperand::MOTargetNumBits),
-                "Too many target MO flags");
-  for (auto *MM : MI.memoperands()) {
-    if (MM->getFlags() &
-        (MOSuppressPair << MachineMemOperand::MOTargetStartBit)) {
-      return true;
-    }
-  }
-  return false;
+  return any_of(MI.memoperands(), [](MachineMemOperand *MMO) {
+    return MMO->getFlags() & MOSuppressPair;
+  });
 }
 
 /// Set a flag on the first MachineMemOperand to suppress pairing.
 void AArch64InstrInfo::suppressLdStPair(MachineInstr &MI) const {
   if (MI.memoperands_empty())
     return;
-
-  static_assert(MOSuppressPair < (1 << MachineMemOperand::MOTargetNumBits),
-                "Too many target MO flags");
-  (*MI.memoperands_begin())
-      ->setFlags(static_cast<MachineMemOperand::Flags>(
-          MOSuppressPair << MachineMemOperand::MOTargetStartBit));
+  (*MI.memoperands_begin())->setFlags(MOSuppressPair);
 }
 
 bool AArch64InstrInfo::isUnscaledLdSt(unsigned Opc) const {