Add a missing doxygen comment for a helper method.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144497 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/MachineBlockPlacement.cpp b/lib/CodeGen/MachineBlockPlacement.cpp
index 3eb2998116d0e1bf225d8f18a860ba51863dddee..ec0877fc05575381f29156bc9519691fe3ab8ca8 100644 (file)
--- a/lib/CodeGen/MachineBlockPlacement.cpp
+++ b/lib/CodeGen/MachineBlockPlacement.cpp
@@ -275,6 +275,12 @@ static std::string getBlockNum(MachineBasicBlock *BB) {
 }
 #endif
 
+/// \brief Mark a chain's successors as having one fewer preds.
+///
+/// When a chain is being merged into the "placed" chain, this routine will
+/// quickly walk the successors of each block in the chain and mark them as
+/// having one fewer active predecessor. It also adds any successors of this
+/// chain which reach the zero-predecessor state to the worklist passed in.
 void MachineBlockPlacement::markChainSuccessors(
     BlockChain &Chain,
     MachineBasicBlock *LoopHeaderBB,