From f0a25f7253745d8aa3c3692e53110fc20a569bd0 Mon Sep 17 00:00:00 2001
From: Florian Hahn <florian.hahn@arm.com>
Date: Tue, 6 Mar 2018 13:12:32 +0000
Subject: [PATCH] [CloneFunction] Support BB == PredBB in
 DuplicateInstructionsInSplit.

In case PredBB == BB and StopAt == BB's terminator, StopAt != &*BI will
fail, because BB's terminator instruction gets replaced.

By using BB.getTerminator() we get the current terminator which we can use
to compare.

Reviewers: sanjoy, anna, reames

Reviewed By: anna

Differential Revision: https://reviews.llvm.org/D43822

llvm-svn: 326779
---
 llvm/lib/Transforms/Utils/CloneFunction.cpp |  4 +-
 llvm/unittests/Transforms/Utils/Cloning.cpp | 98 +++++++++++++++++++++
 2 files changed, 101 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 16af2c7b808b..3bc178ec88b6 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -811,7 +811,9 @@ llvm::DuplicateInstructionsInSplitBetween(BasicBlock *BB, BasicBlock *PredBB,
 
   // Clone the non-phi instructions of BB into NewBB, keeping track of the
   // mapping and using it to remap operands in the cloned instructions.
-  for (; StopAt != &*BI; ++BI) {
+  // Stop once we see the terminator too. This covers the case where BB's
+  // terminator gets replaced and StopAt == BB's terminator.
+  for (; StopAt != &*BI && BB->getTerminator() != &*BI; ++BI) {
     Instruction *New = BI->clone();
     New->setName(BI->getName());
     New->insertBefore(NewTerm);
diff --git a/llvm/unittests/Transforms/Utils/Cloning.cpp b/llvm/unittests/Transforms/Utils/Cloning.cpp
index 2ce19bd51a87..9a1ad19ebaa4 100644
--- a/llvm/unittests/Transforms/Utils/Cloning.cpp
+++ b/llvm/unittests/Transforms/Utils/Cloning.cpp
@@ -251,6 +251,104 @@ TEST_F(CloneInstruction, DuplicateInstructionsToSplit) {
   delete F;
 }
 
+TEST_F(CloneInstruction, DuplicateInstructionsToSplitBlocksEq1) {
+  Type *ArgTy1[] = {Type::getInt32PtrTy(context)};
+  FunctionType *FT = FunctionType::get(Type::getVoidTy(context), ArgTy1, false);
+  V = new Argument(Type::getInt32Ty(context));
+
+  Function *F = Function::Create(FT, Function::ExternalLinkage);
+
+  BasicBlock *BB1 = BasicBlock::Create(context, "", F);
+  IRBuilder<> Builder1(BB1);
+
+  BasicBlock *BB2 = BasicBlock::Create(context, "", F);
+  IRBuilder<> Builder2(BB2);
+
+  Builder1.CreateBr(BB2);
+
+  Instruction *AddInst = cast<Instruction>(Builder2.CreateAdd(V, V));
+  Instruction *MulInst = cast<Instruction>(Builder2.CreateMul(AddInst, V));
+  Instruction *SubInst = cast<Instruction>(Builder2.CreateSub(MulInst, V));
+  Builder2.CreateBr(BB2);
+
+  ValueToValueMapTy Mapping;
+
+  auto Split = DuplicateInstructionsInSplitBetween(BB2, BB2, BB2->getTerminator(), Mapping);
+
+  EXPECT_TRUE(Split);
+  EXPECT_EQ(Mapping.size(), 3u);
+  EXPECT_TRUE(Mapping.find(AddInst) != Mapping.end());
+  EXPECT_TRUE(Mapping.find(MulInst) != Mapping.end());
+  EXPECT_TRUE(Mapping.find(SubInst) != Mapping.end());
+
+  auto AddSplit = dyn_cast<Instruction>(Mapping[AddInst]);
+  EXPECT_TRUE(AddSplit);
+  EXPECT_EQ(AddSplit->getOperand(0), V);
+  EXPECT_EQ(AddSplit->getOperand(1), V);
+  EXPECT_EQ(AddSplit->getParent(), Split);
+
+  auto MulSplit = dyn_cast<Instruction>(Mapping[MulInst]);
+  EXPECT_TRUE(MulSplit);
+  EXPECT_EQ(MulSplit->getOperand(0), AddSplit);
+  EXPECT_EQ(MulSplit->getOperand(1), V);
+  EXPECT_EQ(MulSplit->getParent(), Split);
+
+  auto SubSplit = dyn_cast<Instruction>(Mapping[SubInst]);
+  EXPECT_EQ(MulSplit->getNextNode(), SubSplit);
+  EXPECT_EQ(SubSplit->getNextNode(), Split->getTerminator());
+  EXPECT_EQ(Split->getSingleSuccessor(), BB2);
+  EXPECT_EQ(BB2->getSingleSuccessor(), Split);
+
+  delete F;
+}
+
+TEST_F(CloneInstruction, DuplicateInstructionsToSplitBlocksEq2) {
+  Type *ArgTy1[] = {Type::getInt32PtrTy(context)};
+  FunctionType *FT = FunctionType::get(Type::getVoidTy(context), ArgTy1, false);
+  V = new Argument(Type::getInt32Ty(context));
+
+  Function *F = Function::Create(FT, Function::ExternalLinkage);
+
+  BasicBlock *BB1 = BasicBlock::Create(context, "", F);
+  IRBuilder<> Builder1(BB1);
+
+  BasicBlock *BB2 = BasicBlock::Create(context, "", F);
+  IRBuilder<> Builder2(BB2);
+
+  Builder1.CreateBr(BB2);
+
+  Instruction *AddInst = cast<Instruction>(Builder2.CreateAdd(V, V));
+  Instruction *MulInst = cast<Instruction>(Builder2.CreateMul(AddInst, V));
+  Instruction *SubInst = cast<Instruction>(Builder2.CreateSub(MulInst, V));
+  Builder2.CreateBr(BB2);
+
+  ValueToValueMapTy Mapping;
+
+  auto Split = DuplicateInstructionsInSplitBetween(BB2, BB2, SubInst, Mapping);
+
+  EXPECT_TRUE(Split);
+  EXPECT_EQ(Mapping.size(), 2u);
+  EXPECT_TRUE(Mapping.find(AddInst) != Mapping.end());
+  EXPECT_TRUE(Mapping.find(MulInst) != Mapping.end());
+
+  auto AddSplit = dyn_cast<Instruction>(Mapping[AddInst]);
+  EXPECT_TRUE(AddSplit);
+  EXPECT_EQ(AddSplit->getOperand(0), V);
+  EXPECT_EQ(AddSplit->getOperand(1), V);
+  EXPECT_EQ(AddSplit->getParent(), Split);
+
+  auto MulSplit = dyn_cast<Instruction>(Mapping[MulInst]);
+  EXPECT_TRUE(MulSplit);
+  EXPECT_EQ(MulSplit->getOperand(0), AddSplit);
+  EXPECT_EQ(MulSplit->getOperand(1), V);
+  EXPECT_EQ(MulSplit->getParent(), Split);
+  EXPECT_EQ(MulSplit->getNextNode(), Split->getTerminator());
+  EXPECT_EQ(Split->getSingleSuccessor(), BB2);
+  EXPECT_EQ(BB2->getSingleSuccessor(), Split);
+
+  delete F;
+}
+
 class CloneFunc : public ::testing::Test {
 protected:
   void SetUp() override {