Avoid creating a SlotIndex from the end() iterator.

No test case, spotted by inspection.

llvm-svn: 176705

1 files changed, 10 insertions, 6 deletions

diff --git a/llvm/include/llvm/CodeGen/SlotIndexes.h b/llvm/include/llvm/CodeGen/SlotIndexes.h
index 78fb233e5ff..0f85c994a22 100644
--- a/llvm/include/llvm/CodeGen/SlotIndexes.h
+++ b/llvm/include/llvm/CodeGen/SlotIndexes.h
@@ -396,12 +396,16 @@ namespace llvm {
       return index.isValid() ? index.listEntry()->getInstr() : 0;
     }
 
-    /// Returns the next non-null index.
-    SlotIndex getNextNonNullIndex(SlotIndex index) {
-      IndexList::iterator itr(index.listEntry());
-      ++itr;
-      while (itr != indexList.end() && itr->getInstr() == 0) { ++itr; }
-      return SlotIndex(itr, index.getSlot());
+    /// Returns the next non-null index, if one exists.
+    /// Otherwise returns getLastIndex().
+    SlotIndex getNextNonNullIndex(SlotIndex Index) {
+      IndexList::iterator I = Index.listEntry();
+      IndexList::iterator E = indexList.end();
+      while (I != E)
+        if ((++I)->getInstr())
+          return SlotIndex(I, Index.getSlot());
+      // We reached the end of the function.
+      return getLastIndex();
     }
 
     /// getIndexBefore - Returns the index of the last indexed instruction