Drop ZeroIndex and InvalidIndex.

They are not used any more. Simply use SlotIndex() to get an invalid
index.

llvm-svn: 149727

llvm/include/llvm/CodeGen/LiveIntervalAnalysis.h

@@ -161,14 +161,6 @@ namespace llvm {
       return indexes_;
     }
 
-    SlotIndex getZeroIndex() const {
-      return indexes_->getZeroIndex();
-    }
-
-    SlotIndex getInvalidIndex() const {
-      return indexes_->getInvalidIndex();
-    }
-
     /// isNotInMIMap - returns true if the specified machine instr has been
     /// removed or was never entered in the map.
     bool isNotInMIMap(const MachineInstr* Instr) const {

llvm/include/llvm/CodeGen/SlotIndexes.h

@@ -472,11 +472,6 @@ namespace llvm {
       return SlotIndex(back(), 0);
     }
 
-    /// Returns the invalid index marker for this analysis.
-    SlotIndex getInvalidIndex() {
-      return getZeroIndex();
-    }
-
     /// Returns the distance between the highest and lowest indexes allocated
     /// so far.
     unsigned getIndexesLength() const {