1 files changed, 62 insertions, 0 deletions
diff --git a/lib/CodeGen/LiveRangeUtils.h b/lib/CodeGen/LiveRangeUtils.h
new file mode 100644
index 000000000000..bd57609c3d84
--- /dev/null
+++ b/lib/CodeGen/LiveRangeUtils.h
@@ -0,0 +1,62 @@
+//===-- LiveRangeUtils.h - Live Range modification utilities ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+/// This file contains helper functions to modify live ranges.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_CODEGEN_LIVERANGEUTILS_H
+#define LLVM_LIB_CODEGEN_LIVERANGEUTILS_H
+
+#include "llvm/CodeGen/LiveInterval.h"
+
+namespace llvm {
+
+/// Helper function that distributes live range value numbers and the
+/// corresponding segments of a master live range \p LR to a list of newly
+/// created live ranges \p SplitLRs. \p VNIClasses maps each value number in \p
+/// LR to 0 meaning it should stay or to 1..N meaning it should go to a specific
+/// live range in the \p SplitLRs array.
+template<typename LiveRangeT, typename EqClassesT>
+static void DistributeRange(LiveRangeT &LR, LiveRangeT *SplitLRs[],
+                            EqClassesT VNIClasses) {
+  // Move segments to new intervals.
+  typename LiveRangeT::iterator J = LR.begin(), E = LR.end();
+  while (J != E && VNIClasses[J->valno->id] == 0)
+    ++J;
+  for (typename LiveRangeT::iterator I = J; I != E; ++I) {
+    if (unsigned eq = VNIClasses[I->valno->id]) {
+      assert((SplitLRs[eq-1]->empty() || SplitLRs[eq-1]->expiredAt(I->start)) &&
+             "New intervals should be empty");
+      SplitLRs[eq-1]->segments.push_back(*I);
+    } else
+      *J++ = *I;
+  }
+  LR.segments.erase(J, E);
+
+  // Transfer VNInfos to their new owners and renumber them.
+  unsigned j = 0, e = LR.getNumValNums();
+  while (j != e && VNIClasses[j] == 0)
+    ++j;
+  for (unsigned i = j; i != e; ++i) {
+    VNInfo *VNI = LR.getValNumInfo(i);
+    if (unsigned eq = VNIClasses[i]) {
+      VNI->id = SplitLRs[eq-1]->getNumValNums();
+      SplitLRs[eq-1]->valnos.push_back(VNI);
+    } else {
+      VNI->id = j;
+      LR.valnos[j++] = VNI;
+    }
+  }
+  LR.valnos.resize(j);
+}
+
+} // End llvm namespace
+
+#endif