Find anchoring end points for repairIntervalsInRange and repairIndexesInRange
automatically.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175673 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SlotIndexes.cpp b/lib/CodeGen/SlotIndexes.cpp
index b4e562e..f293794 100644
--- a/lib/CodeGen/SlotIndexes.cpp
+++ b/lib/CodeGen/SlotIndexes.cpp
@@ -146,6 +146,15 @@
 void SlotIndexes::repairIndexesInRange(MachineBasicBlock *MBB,
                                        MachineBasicBlock::iterator Begin,
                                        MachineBasicBlock::iterator End) {
+  // FIXME: Is this really necessary? The only caller repairIntervalsForRange()
+  // does the same thing.
+  // Find anchor points, which are at the beginning/end of blocks or at
+  // instructions that already have indexes.
+  while (Begin != MBB->begin() && !hasIndex(Begin))
+    --Begin;
+  while (End != MBB->end() && !hasIndex(End))
+    ++End;
+
   bool includeStart = (Begin == MBB->begin());
   SlotIndex startIdx;
   if (includeStart)