Revert part of r91101 which was causing an infinite loop in the self-hosting
build bots.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91113 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp
index 7ce723e..0097dd1 100644
--- a/lib/CodeGen/MachineBasicBlock.cpp
+++ b/lib/CodeGen/MachineBasicBlock.cpp
@@ -457,11 +457,16 @@
   SmallSet<const MachineBasicBlock*, 32> Visited;
   const MachineBasicBlock *CurMBB = MBB;
 
-  while (!CurMBB->isLandingPad()) {
-    if (CurMBB->succ_size() != 1)
+  while (!Visited.count(CurMBB) && !CurMBB->isLandingPad()) {
+    if (CurMBB->size() != 1 || CurMBB->succ_empty() || CurMBB->succ_size() != 1)
       break;
 
-    if (!Visited.insert(CurMBB)) break;
+    const TargetInstrInfo *TII =
+      CurMBB->getParent()->getTarget().getInstrInfo();
+    if (!TII->isUnpredicatedTerminator(CurMBB->begin()))
+      break;
+
+    Visited.insert(CurMBB);
     CurMBB = *CurMBB->succ_begin();
   }