If a MachineBasicBlock has multiple ways of reaching another block,

allow it to have multiple CFG edges to that block. This is needed
to allow MachineBasicBlock::isOnlyReachableByFallthrough to work
correctly. This fixes PR4126.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71018 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 4 deletions

diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp
index 5ac54ea8a4..71e6b3e4d0 100644
--- a/lib/CodeGen/MachineBasicBlock.cpp
+++ b/lib/CodeGen/MachineBasicBlock.cpp
@@ -305,11 +305,9 @@ void MachineBasicBlock::ReplaceUsesOfBlockWith(MachineBasicBlock *Old,
         I->getOperand(i).setMBB(New);
   }
 
-  // Update the successor information.  If New was already a successor, just
-  // remove the link to Old instead of creating another one.  PR 1444.
+  // Update the successor information.
   removeSuccessor(Old);
-  if (!isSuccessor(New))
-    addSuccessor(New);
+  addSuccessor(New);
 }
 
 /// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in the