2 files changed, 34 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Utils/CMakeLists.txt b/llvm/lib/Transforms/Utils/CMakeLists.txt
index 7a21c03da22..83bc05d0311 100644
--- a/llvm/lib/Transforms/Utils/CMakeLists.txt
+++ b/llvm/lib/Transforms/Utils/CMakeLists.txt
@@ -37,6 +37,7 @@ add_llvm_library(LLVMTransformUtils
   MetaRenamer.cpp
   ModuleUtils.cpp
   NameAnonGlobals.cpp
+  OrderedInstructions.cpp
   PredicateInfo.cpp
   PromoteMemoryToRegister.cpp
   StripGCRelocates.cpp
diff --git a/llvm/lib/Transforms/Utils/OrderedInstructions.cpp b/llvm/lib/Transforms/Utils/OrderedInstructions.cpp
new file mode 100644
index 00000000000..2e67e0def5b
--- /dev/null
+++ b/llvm/lib/Transforms/Utils/OrderedInstructions.cpp
@@ -0,0 +1,33 @@
+//===-- OrderedInstructions.cpp - Instruction dominance function ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines utility to check dominance relation of 2 instructions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Utils/OrderedInstructions.h"
+using namespace llvm;
+
+/// Given 2 instructions, use OrderedBasicBlock to check for dominance relation
+/// if the instructions are in the same basic block, Otherwise, use dominator
+/// tree.
+bool OrderedInstructions::dominates(const Instruction *InstA,
+                                    const Instruction *InstB) const {
+  const BasicBlock *IBB = InstA->getParent();
+  // Use ordered basic block to do dominance check in case the 2 instructions
+  // are in the same basic block.
+  if (IBB == InstB->getParent()) {
+    auto OBB = OBBMap.find(IBB);
+    if (OBB == OBBMap.end())
+      OBB = OBBMap.insert({IBB, make_unique<OrderedBasicBlock>(IBB)}).first;
+    return OBB->second->dominates(InstA, InstB);
+  } else {
+    return DT->dominates(InstA->getParent(), InstB->getParent());
+  }
+}