Add SlotIndexes::repairIndexesInRange(), which repairs SlotIndexes after adding

and removing instructions. The implementation seems more complicated than it
needs to be, but I couldn't find something simpler that dealt with all of the
corner cases.

Also add a call to repairIndexesInRange() from repairIntervalsInRange().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175601 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/SlotIndexes.h

@@ -360,6 +360,11 @@ namespace llvm {
     /// Renumber the index list, providing space for new instructions.
     void renumberIndexes();
 
+    /// Repair indexes after adding and removing instructions.
+    void repairIndexesInRange(MachineBasicBlock *MBB,
+                              MachineBasicBlock::iterator Begin,
+                              MachineBasicBlock::iterator End);
+
     /// Returns the zero index for this analysis.
     SlotIndex getZeroIndex() {
       assert(indexList.front().getIndex() == 0 && "First index is not 0?");