Modify df_iterator to support post-order actions

Summary: This makes a change to the state used to maintain visited information for depth first iterator. We know assume a method "completed(...)" which is called after all children of a node have been visited. In all existing cases, this method does nothing so this patch has no functional changes.  It will however allow a client to distinguish back from cross edges in a DFS tree.

Reviewers: nadav, mehdi_amini, dberlin

Subscribers: MatzeB, mzolotukhin, twoh, freik, llvm-commits

Differential Revision: https://reviews.llvm.org/D25191

llvm-svn: 283391

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/LiveVariables.cpp b/llvm/lib/CodeGen/LiveVariables.cpp
index dd87216f5e6..269b990a314 100644
--- a/llvm/lib/CodeGen/LiveVariables.cpp
+++ b/llvm/lib/CodeGen/LiveVariables.cpp
@@ -643,7 +643,7 @@ bool LiveVariables::runOnMachineFunction(MachineFunction &mf) {
   // register before its uses due to dominance properties of SSA (except for PHI
   // nodes, which are treated as a special case).
   MachineBasicBlock *Entry = &MF->front();
-  SmallPtrSet<MachineBasicBlock*,16> Visited;
+  df_iterator_default_set<MachineBasicBlock*,16> Visited;
 
   for (MachineBasicBlock *MBB : depth_first_ext(Entry, Visited)) {
     runOnBlock(MBB, NumRegs);