Improve MachineMemOperand handling.

- Allocate MachineMemOperands and MachineMemOperand lists in MachineFunctions.
   This eliminates MachineInstr's std::list member and allows the data to be
   created by isel and live for the remainder of codegen, avoiding a lot of
   copying and unnecessary translation. This also shrinks MemSDNode.
 - Delete MemOperandSDNode. Introduce MachineSDNode which has dedicated
   fields for MachineMemOperands.
 - Change MemSDNode to have a MachineMemOperand member instead of its own
   fields with the same information. This introduces some redundancy, but
   it's more consistent with what MachineInstr will eventually want.
 - Ignore alignment when searching for redundant loads for CSE, but remember
   the greatest alignment.

Target-specific code which previously used MemOperandSDNodes with generic
SDNodes now use MemIntrinsicSDNodes, with opcodes in a designated range
so that the SelectionDAG framework knows that MachineMemOperand information
is available.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82794 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/MachineMemOperand.h

@@ -88,6 +88,16 @@ public:
   bool isStore() const { return Flags & MOStore; }
   bool isVolatile() const { return Flags & MOVolatile; }
 
+  /// refineAlignment - Update this MachineMemOperand to reflect the alignment
+  /// of MMO, if it has a greater alignment. This must only be used when the
+  /// new alignment applies to all users of this MachineMemOperand.
+  void refineAlignment(const MachineMemOperand *MMO);
+
+  /// setValue - Change the SourceValue for this MachineMemOperand. This
+  /// should only be used when an object is being relocated and all references
+  /// to it are being updated.
+  void setValue(const Value *NewSV) { V = NewSV; }
+
   /// Profile - Gather unique data for the object.
   ///
   void Profile(FoldingSetNodeID &ID) const;