1 files changed, 26 insertions, 7 deletions
diff --git a/lib/Transforms/Utils/OrderedInstructions.cpp b/lib/Transforms/Utils/OrderedInstructions.cpp
index dc780542ce68..6d0b96f6aa8a 100644
--- a/lib/Transforms/Utils/OrderedInstructions.cpp
+++ b/lib/Transforms/Utils/OrderedInstructions.cpp
@@ -14,19 +14,38 @@
 #include "llvm/Transforms/Utils/OrderedInstructions.h"
 using namespace llvm;
 
+bool OrderedInstructions::localDominates(const Instruction *InstA,
+                                         const Instruction *InstB) const {
+  assert(InstA->getParent() == InstB->getParent() &&
+         "Instructions must be in the same basic block");
+
+  const BasicBlock *IBB = InstA->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);
+}
+
 /// 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);
-  }
+  if (InstA->getParent() == InstB->getParent())
+    return localDominates(InstA, InstB);
   return DT->dominates(InstA->getParent(), InstB->getParent());
 }
+
+bool OrderedInstructions::dfsBefore(const Instruction *InstA,
+                                    const Instruction *InstB) const {
+  // Use ordered basic block in case the 2 instructions are in the same basic
+  // block.
+  if (InstA->getParent() == InstB->getParent())
+    return localDominates(InstA, InstB);
+
+  DomTreeNode *DA = DT->getNode(InstA->getParent());
+  DomTreeNode *DB = DT->getNode(InstB->getParent());
+  return DA->getDFSNumIn() < DB->getDFSNumIn();
+}