1 files changed, 4 insertions, 1 deletions
diff --git a/lib/CodeGen/MachineBlockPlacement.cpp b/lib/CodeGen/MachineBlockPlacement.cpp
index 4cbc94e0b7..0d15e8a726 100644
--- a/lib/CodeGen/MachineBlockPlacement.cpp
+++ b/lib/CodeGen/MachineBlockPlacement.cpp
@@ -488,7 +488,10 @@ MachineBasicBlock *MachineBlockPlacement::getFirstUnplacedBlock(
       continue;
     if (BlockToChain[I] != &PlacedChain) {
       PrevUnplacedBlockIt = I;
-      return I;
+      // Now select the head of the chain to which the unplaced block belongs
+      // as the block to place. This will force the entire chain to be placed,
+      // and satisfies the requirements of merging chains.
+      return *BlockToChain[I]->begin();
     }
   }
   return 0;