Index: lib/CodeGen/BranchRelaxation.cpp
===================================================================
--- lib/CodeGen/BranchRelaxation.cpp
+++ lib/CodeGen/BranchRelaxation.cpp
@@ -116,6 +116,7 @@
     unsigned Num = MBB.getNumber();
     assert(BlockInfo[Num].Offset % (1u << Align) == 0);
     assert(!Num || BlockInfo[PrevNum].postOffset(MBB) <= BlockInfo[Num].Offset);
+    assert(BlockInfo[Num].Size == computeBlockSize(MBB));
     PrevNum = Num;
   }
 #endif
@@ -385,12 +386,9 @@
 
   DebugLoc DL = MI.getDebugLoc();
   MI.eraseFromParent();
-
-  // insertUnconditonalBranch may have inserted a new block.
-  BlockInfo[MBB->getNumber()].Size += TII->insertIndirectBranch(
+  BlockInfo[BranchBB->getNumber()].Size += TII->insertIndirectBranch(
     *BranchBB, *DestBB, DL, DestOffset - SrcOffset, RS.get());
 
-  computeBlockSize(*BranchBB);
   adjustBlockOffsets(*MBB);
   return true;
 }