Move PHIElimination's SplitCriticalEdge for MachineBasicBlocks out

into a utility routine, teach it how to update MachineLoopInfo, and
make use of it in MachineLICM to split critical edges on demand.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106555 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/MachineBasicBlock.h b/include/llvm/CodeGen/MachineBasicBlock.h
index cc651ca77b..82f9c0f25f 100644
--- a/include/llvm/CodeGen/MachineBasicBlock.h
+++ b/include/llvm/CodeGen/MachineBasicBlock.h
@@ -19,6 +19,7 @@
 
 namespace llvm {
 
+class Pass;
 class BasicBlock;
 class MachineFunction;
 class MCSymbol;
@@ -281,6 +282,14 @@ public:
   /// it returns end()
   iterator getFirstTerminator();
 
+  /// SplitCriticalEdge - Split the critical edge from this block to the
+  /// given successor block, and return the newly created block, or null
+  /// if splitting is not possible.
+  ///
+  /// This function updates LiveVariables, MachineDominatorTree, and
+  /// MachineLoopInfo, as applicable.
+  MachineBasicBlock *SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P);
+
   void pop_front() { Insts.pop_front(); }
   void pop_back() { Insts.pop_back(); }
   void push_back(MachineInstr *MI) { Insts.push_back(MI); }