1 files changed, 64 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/LiveRangeEdit.cpp b/llvm/lib/CodeGen/LiveRangeEdit.cpp
new file mode 100644
index 00000000000..8a123fbe701
--- /dev/null
+++ b/llvm/lib/CodeGen/LiveRangeEdit.cpp
@@ -0,0 +1,64 @@
+//===--- LiveRangeEdit.cpp - Basic tools for editing a register live range --===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// The LiveRangeEdit class represents changes done to a virtual register when it
+// is spilled or split.
+//===----------------------------------------------------------------------===//
+
+#include "LiveRangeEdit.h"
+#include "VirtRegMap.h"
+#include "llvm/CodeGen/LiveIntervalAnalysis.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+
+using namespace llvm;
+
+LiveInterval &LiveRangeEdit::create(MachineRegisterInfo &mri,
+                                    LiveIntervals &lis,
+                                    VirtRegMap &vrm) {
+  const TargetRegisterClass *RC = mri.getRegClass(parent_.reg);
+  unsigned VReg = mri.createVirtualRegister(RC);
+  vrm.grow();
+  LiveInterval &li = lis.getOrCreateInterval(VReg);
+  newRegs_.push_back(&li);
+  return li;
+}
+
+/// allUsesAvailableAt - Return true if all registers used by OrigMI at
+/// OrigIdx are also available with the same value at UseIdx.
+bool LiveRangeEdit::allUsesAvailableAt(const MachineInstr *OrigMI,
+                                       SlotIndex OrigIdx,
+                                       SlotIndex UseIdx,
+                                       LiveIntervals &lis) {
+  OrigIdx = OrigIdx.getUseIndex();
+  UseIdx = UseIdx.getUseIndex();
+  for (unsigned i = 0, e = OrigMI->getNumOperands(); i != e; ++i) {
+    const MachineOperand &MO = OrigMI->getOperand(i);
+    if (!MO.isReg() || !MO.getReg() || MO.getReg() == getReg())
+      continue;
+    // Reserved registers are OK.
+    if (MO.isUndef() || !lis.hasInterval(MO.getReg()))
+      continue;
+    // We don't want to move any defs.
+    if (MO.isDef())
+      return false;
+    // We cannot depend on virtual registers in uselessRegs_.
+    for (unsigned ui = 0, ue = uselessRegs_.size(); ui != ue; ++ui)
+      if (uselessRegs_[ui]->reg == MO.getReg())
+        return false;
+
+    LiveInterval &li = lis.getInterval(MO.getReg());
+    const VNInfo *OVNI = li.getVNInfoAt(OrigIdx);
+    if (!OVNI)
+      continue;
+    if (OVNI != li.getVNInfoAt(UseIdx))
+      return false;
+  }
+  return true;
+}
+