CodeGen: Move split block utility to MachineBasicBlock

AMDGPU needs this in several places, so consolidate them here.

1 files changed, 40 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MachineBasicBlock.cpp b/llvm/lib/CodeGen/MachineBasicBlock.cpp
index 42d5199..8a37a1e 100644
--- a/llvm/lib/CodeGen/MachineBasicBlock.cpp
+++ b/llvm/lib/CodeGen/MachineBasicBlock.cpp
@@ -944,6 +944,46 @@ bool MachineBasicBlock::canFallThrough() {
   return getFallThrough() != nullptr;
 }
 
+MachineBasicBlock *MachineBasicBlock::splitAt(MachineInstr &MI,
+                                              bool UpdateLiveIns,
+                                              LiveIntervals *LIS) {
+  MachineBasicBlock::iterator SplitPoint(&MI);
+  ++SplitPoint;
+
+  if (SplitPoint == end()) {
+    // Don't bother with a new block.
+    return this;
+  }
+
+  MachineFunction *MF = getParent();
+
+  LivePhysRegs LiveRegs;
+  if (UpdateLiveIns) {
+    // Make sure we add any physregs we define in the block as liveins to the
+    // new block.
+    LiveRegs.init(*MF->getSubtarget().getRegisterInfo());
+    LiveRegs.addLiveOuts(*this);
+    for (auto I = rbegin(), E = SplitPoint.getReverse(); I != E; ++I)
+      LiveRegs.stepBackward(*I);
+  }
+
+  MachineBasicBlock *SplitBB = MF->CreateMachineBasicBlock(getBasicBlock());
+
+  MF->insert(++MachineFunction::iterator(this), SplitBB);
+  SplitBB->splice(SplitBB->begin(), this, SplitPoint, end());
+
+  SplitBB->transferSuccessorsAndUpdatePHIs(this);
+  addSuccessor(SplitBB);
+
+  if (UpdateLiveIns)
+    addLiveIns(*SplitBB, LiveRegs);
+
+  if (LIS)
+    LIS->insertMBBInMaps(SplitBB, &MI);
+
+  return SplitBB;
+}
+
 MachineBasicBlock *MachineBasicBlock::SplitCriticalEdge(
     MachineBasicBlock *Succ, Pass &P,
     std::vector<SparseBitVector<>> *LiveInSets) {