Pack MachineInstr fields better.

This shrinks MachineInstr to 64 bytes (from 72).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171813 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/MachineInstr.h

@@ -87,7 +87,7 @@ private:
                                         // anything other than to convey comment
                                         // information to AsmPrinter.
 
-  uint16_t NumMemRefs;                  // information on memory references
+  uint8_t NumMemRefs;                   // Information on memory references.
   mmo_iterator MemRefs;
 
   DebugLoc debugLoc;                    // Source line information.
@@ -993,7 +993,8 @@ public:
   /// list. This does not transfer ownership.
   void setMemRefs(mmo_iterator NewMemRefs, mmo_iterator NewMemRefsEnd) {
     MemRefs = NewMemRefs;
-    NumMemRefs = NewMemRefsEnd - NewMemRefs;
+    NumMemRefs = uint8_t(NewMemRefsEnd - NewMemRefs);
+    assert(NumMemRefs == NewMemRefsEnd - NewMemRefs && "Too many memrefs");
   }
 
 private:

lib/CodeGen/MachineInstr.cpp

@@ -741,16 +741,14 @@ void MachineInstr::RemoveOperand(unsigned OpNo) {
 void MachineInstr::addMemOperand(MachineFunction &MF,
                                  MachineMemOperand *MO) {
   mmo_iterator OldMemRefs = MemRefs;
-  uint16_t OldNumMemRefs = NumMemRefs;
+  unsigned OldNumMemRefs = NumMemRefs;
 
-  uint16_t NewNum = NumMemRefs + 1;
+  unsigned NewNum = NumMemRefs + 1;
   mmo_iterator NewMemRefs = MF.allocateMemRefsArray(NewNum);
 
   std::copy(OldMemRefs, OldMemRefs + OldNumMemRefs, NewMemRefs);
   NewMemRefs[NewNum - 1] = MO;
-
-  MemRefs = NewMemRefs;
-  NumMemRefs = NewNum;
+  setMemRefs(NewMemRefs, NewMemRefs + NewNum);
 }
 
 bool MachineInstr::hasPropertyInBundle(unsigned Mask, QueryType Type) const {