1 files changed, 67 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/TailDuplication.cpp b/contrib/llvm/lib/CodeGen/TailDuplication.cpp
new file mode 100644
index 000000000000..489a607eb176
--- /dev/null
+++ b/contrib/llvm/lib/CodeGen/TailDuplication.cpp
@@ -0,0 +1,67 @@
+//===- TailDuplication.cpp - Duplicate blocks into predecessors' tails ----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass duplicates basic blocks ending in unconditional branches into
+// the tails of their predecessors, using the TailDuplicator utility class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/TailDuplicator.h"
+#include "llvm/Pass.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "tailduplication"
+
+namespace {
+
+/// Perform tail duplication. Delegates to TailDuplicator
+class TailDuplicatePass : public MachineFunctionPass {
+  TailDuplicator Duplicator;
+
+public:
+  static char ID;
+
+  explicit TailDuplicatePass() : MachineFunctionPass(ID) {}
+
+  bool runOnMachineFunction(MachineFunction &MF) override;
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+};
+
+} // end anonymous namespace
+
+char TailDuplicatePass::ID = 0;
+
+char &llvm::TailDuplicateID = TailDuplicatePass::ID;
+
+INITIALIZE_PASS(TailDuplicatePass, DEBUG_TYPE, "Tail Duplication", false, false)
+
+bool TailDuplicatePass::runOnMachineFunction(MachineFunction &MF) {
+  if (skipFunction(*MF.getFunction()))
+    return false;
+
+  auto MBPI = &getAnalysis<MachineBranchProbabilityInfo>();
+
+  Duplicator.initMF(MF, MBPI, /* LayoutMode */ false);
+
+  bool MadeChange = false;
+  while (Duplicator.tailDuplicateBlocks())
+    MadeChange = true;
+
+  return MadeChange;
+}
+
+void TailDuplicatePass::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.addRequired<MachineBranchProbabilityInfo>();
+  MachineFunctionPass::getAnalysisUsage(AU);
+}