[clang] [llvm] [LLVM] Add IRNormalizer Pass (PR #68176)

Justin Fargnoli via llvm-commits llvm-commits at lists.llvm.org
Mon May 6 19:25:12 PDT 2024


https://github.com/justinfargnoli updated https://github.com/llvm/llvm-project/pull/68176

>From 545203edd57ea86c834dc3a063583adf7441b603 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 12 Aug 2023 10:58:45 -0700
Subject: [PATCH 01/50] Add IRCanonicalizer.cpp

---
 llvm/lib/Transforms/Utils/CMakeLists.txt      |   1 +
 llvm/lib/Transforms/Utils/IRCanonicalizer.cpp | 632 ++++++++++++++++++
 2 files changed, 633 insertions(+)
 create mode 100644 llvm/lib/Transforms/Utils/IRCanonicalizer.cpp

diff --git a/llvm/lib/Transforms/Utils/CMakeLists.txt b/llvm/lib/Transforms/Utils/CMakeLists.txt
index 51e8821773c3af..3e9aae240269eb 100644
--- a/llvm/lib/Transforms/Utils/CMakeLists.txt
+++ b/llvm/lib/Transforms/Utils/CMakeLists.txt
@@ -35,6 +35,7 @@ add_llvm_component_library(LLVMTransformUtils
   InjectTLIMappings.cpp
   InstructionNamer.cpp
   IntegerDivision.cpp
+  IRCanonicalizer.cpp
   LCSSA.cpp
   LibCallsShrinkWrap.cpp
   Local.cpp
diff --git a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
new file mode 100644
index 00000000000000..58e2dce0b96685
--- /dev/null
+++ b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
@@ -0,0 +1,632 @@
+//===--------------- IRCanonicalizer.cpp - IR Canonicalizer ---------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file implements the IRCanonicalizer class which aims to transform LLVM
+/// Modules into a canonical form by reordering and renaming instructions while
+/// preserving the same semantics. The canonicalizer makes it easier to spot
+/// semantic differences while diffing two modules which have undergone
+/// different passes.
+///
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Module.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/Pass.h"
+#include "llvm/PassRegistry.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Transforms/Utils.h"
+#include <algorithm>
+#include <vector>
+
+#define DEBUG_TYPE "canon"
+
+using namespace llvm;
+
+namespace {
+/// IRCanonicalizer aims to transform LLVM IR into canonical form.
+class IRCanonicalizer : public FunctionPass {
+public:
+  static char ID;
+
+  /// \name Canonicalizer flags.
+  /// @{
+  /// Preserves original order of instructions.
+  static cl::opt<bool> PreserveOrder;
+  /// Renames all instructions (including user-named).
+  static cl::opt<bool> RenameAll;
+  /// Folds all regular instructions (including pre-outputs).
+  static cl::opt<bool> FoldPreoutputs;
+  /// Sorts and reorders operands in commutative instructions.
+  static cl::opt<bool> ReorderOperands;
+  /// @}
+
+  /// Constructor for the IRCanonicalizer.
+  IRCanonicalizer() : FunctionPass(ID) {}
+
+  bool runOnFunction(Function &F) override;
+
+private:
+  // Random constant for hashing, so the state isn't zero.
+  const uint64_t MagicHashConstant = 0x6acaa36bef8325c5ULL;
+
+  /// \name Naming.
+  /// @{
+  void nameFunctionArguments(Function &F);
+  void nameBasicBlocks(Function &F);
+  void nameInstruction(Instruction *I);
+  void nameAsInitialInstruction(Instruction *I);
+  void nameAsRegularInstruction(Instruction *I);
+  void foldInstructionName(Instruction *I);
+  /// @}
+
+  /// \name Reordering.
+  /// @{
+  void reorderInstructions(SmallVector<Instruction *, 16> &Outputs);
+  void reorderInstruction(Instruction *Used, Instruction *User,
+                          SmallPtrSet<const Instruction *, 32> &Visited);
+  void reorderInstructionOperandsByNames(Instruction *I);
+  void reorderPHIIncomingValues(PHINode *PN);
+  /// @}
+
+  /// \name Utility methods.
+  /// @{
+  SmallVector<Instruction *, 16> collectOutputInstructions(Function &F);
+  bool isOutput(const Instruction *I);
+  bool isInitialInstruction(const Instruction *I);
+  bool hasOnlyImmediateOperands(const Instruction *I);
+  SetVector<int>
+  getOutputFootprint(Instruction *I,
+                     SmallPtrSet<const Instruction *, 32> &Visited);
+  /// @}
+};
+} // namespace
+
+char IRCanonicalizer::ID = 0;
+static RegisterPass<IRCanonicalizer> X("canon", "Canonicalize the IR",
+                                       false /* Only looks at CFG */,
+                                       false /* Analysis Pass */);
+
+cl::opt<bool> IRCanonicalizer::PreserveOrder(
+    "preserve-order", cl::Hidden,
+    cl::desc("Preserves original instruction order"));
+cl::opt<bool> IRCanonicalizer::RenameAll(
+    "rename-all", cl::Hidden,
+    cl::desc("Renames all instructions (including user-named)"));
+cl::opt<bool> IRCanonicalizer::FoldPreoutputs(
+    "fold-all", cl::Hidden,
+    cl::desc("Folds all regular instructions (including pre-outputs)"));
+cl::opt<bool> IRCanonicalizer::ReorderOperands(
+    "reorder-operands", cl::Hidden,
+    cl::desc("Sorts and reorders operands in commutative instructions"));
+
+/// Entry method to the IRCanonicalizer.
+///
+/// \param M Module to canonicalize.
+bool IRCanonicalizer::runOnFunction(Function &F) {
+  nameFunctionArguments(F);
+  nameBasicBlocks(F);
+
+  SmallVector<Instruction *, 16> Outputs = collectOutputInstructions(F);
+
+  if (!PreserveOrder)
+    reorderInstructions(Outputs);
+
+  for (auto &I : Outputs)
+    nameInstruction(I);
+
+  for (auto &I : instructions(F)) {
+    if (!PreserveOrder) {
+      if (ReorderOperands && I.isCommutative())
+        reorderInstructionOperandsByNames(&I);
+
+      if (auto *PN = dyn_cast<PHINode>(&I))
+        reorderPHIIncomingValues(PN);
+    }
+
+    foldInstructionName(&I);
+  }
+
+  return true;
+}
+
+/// Numbers arguments.
+///
+/// \param F Function whose arguments will be renamed.
+void IRCanonicalizer::nameFunctionArguments(Function &F) {
+  int ArgumentCounter = 0;
+  for (auto &A : F.args()) {
+    if (RenameAll || A.getName().empty()) {
+      A.setName("a" + Twine(ArgumentCounter));
+      ++ArgumentCounter;
+    }
+  }
+}
+
+/// Names basic blocks using a generated hash for each basic block in
+/// a function considering the opcode and the order of output instructions.
+///
+/// \param F Function containing basic blocks to rename.
+void IRCanonicalizer::nameBasicBlocks(Function &F) {
+  for (auto &B : F) {
+    // Initialize to a magic constant, so the state isn't zero.
+    uint64_t Hash = MagicHashConstant;
+
+    // Hash considering output instruction opcodes.
+    for (auto &I : B)
+      if (isOutput(&I))
+        Hash = hashing::detail::hash_16_bytes(Hash, I.getOpcode());
+
+    if (RenameAll || B.getName().empty()) {
+      // Name basic block. Substring hash to make diffs more readable.
+      B.setName("bb" + std::to_string(Hash).substr(0, 5));
+    }
+  }
+}
+
+/// Names instructions graphically (recursive) in accordance with the
+/// def-use tree, starting from the initial instructions (defs), finishing at
+/// the output (top-most user) instructions (depth-first).
+///
+/// \param I Instruction to be renamed.
+void IRCanonicalizer::nameInstruction(Instruction *I) {
+  // Determine the type of instruction to name.
+  if (isInitialInstruction(I)) {
+    // This is an initial instruction.
+    nameAsInitialInstruction(I);
+  } else {
+    // This must be a regular instruction.
+    nameAsRegularInstruction(I);
+  }
+}
+
+/// Names instruction following the scheme:
+/// vl00000Callee(Operands)
+///
+/// Where 00000 is a hash calculated considering instruction's opcode and output
+/// footprint. Callee's name is only included when instruction's type is
+/// CallInst. In cases where instruction is commutative, operands list is also
+/// sorted.
+///
+/// Renames instruction only when RenameAll flag is raised or instruction is
+/// unnamed.
+///
+/// \see getOutputFootprint()
+/// \param I Instruction to be renamed.
+void IRCanonicalizer::nameAsInitialInstruction(Instruction *I) {
+  if (I->getType()->isVoidTy() || (!I->getName().empty() && !RenameAll))
+    return;
+
+  // Instruction operands for further sorting.
+  SmallVector<SmallString<64>, 4> Operands;
+
+  // Collect operands.
+  for (auto &OP : I->operands()) {
+    if (!isa<Function>(OP)) {
+      std::string TextRepresentation;
+      raw_string_ostream Stream(TextRepresentation);
+      OP->printAsOperand(Stream, false);
+      Operands.push_back(StringRef(Stream.str()));
+    }
+  }
+
+  if (I->isCommutative())
+    llvm::sort(Operands);
+
+  // Initialize to a magic constant, so the state isn't zero.
+  uint64_t Hash = MagicHashConstant;
+
+  // Consider instruction's opcode in the hash.
+  Hash = hashing::detail::hash_16_bytes(Hash, I->getOpcode());
+
+  SmallPtrSet<const Instruction *, 32> Visited;
+  // Get output footprint for I.
+  SetVector<int> OutputFootprint = getOutputFootprint(I, Visited);
+
+  // Consider output footprint in the hash.
+  for (const int &Output : OutputFootprint)
+    Hash = hashing::detail::hash_16_bytes(Hash, Output);
+
+  // Base instruction name.
+  SmallString<256> Name;
+  Name.append("vl" + std::to_string(Hash).substr(0, 5));
+
+  // In case of CallInst, consider callee in the instruction name.
+  if (const auto *CI = dyn_cast<CallInst>(I)) {
+    Function *F = CI->getCalledFunction();
+
+    if (F != nullptr) {
+      Name.append(F->getName());
+    }
+  }
+
+  Name.append("(");
+  for (unsigned long i = 0; i < Operands.size(); ++i) {
+    Name.append(Operands[i]);
+
+    if (i < Operands.size() - 1)
+      Name.append(", ");
+  }
+  Name.append(")");
+
+  I->setName(Name);
+}
+
+/// Names instruction following the scheme:
+/// op00000Callee(Operands)
+///
+/// Where 00000 is a hash calculated considering instruction's opcode, its
+/// operands' opcodes and order. Callee's name is only included when
+/// instruction's type is CallInst. In cases where instruction is commutative,
+/// operand list is also sorted.
+///
+/// Names instructions recursively in accordance with the def-use tree,
+/// starting from the initial instructions (defs), finishing at
+/// the output (top-most user) instructions (depth-first).
+///
+/// Renames instruction only when RenameAll flag is raised or instruction is
+/// unnamed.
+///
+/// \see getOutputFootprint()
+/// \param I Instruction to be renamed.
+void IRCanonicalizer::nameAsRegularInstruction(Instruction *I) {
+  // Instruction operands for further sorting.
+  SmallVector<SmallString<128>, 4> Operands;
+
+  // The name of a regular instruction depends
+  // on the names of its operands. Hence, all
+  // operands must be named first in the use-def
+  // walk.
+
+  // Collect operands.
+  for (auto &OP : I->operands()) {
+    if (auto *IOP = dyn_cast<Instruction>(OP)) {
+      // Walk down the use-def chain.
+      nameInstruction(IOP);
+      Operands.push_back(IOP->getName());
+    } else if (isa<Value>(OP) && !isa<Function>(OP)) {
+      // This must be an immediate value.
+      std::string TextRepresentation;
+      raw_string_ostream Stream(TextRepresentation);
+      OP->printAsOperand(Stream, false);
+      Operands.push_back(StringRef(Stream.str()));
+    }
+  }
+
+  if (I->isCommutative())
+    llvm::sort(Operands.begin(), Operands.end());
+
+  // Initialize to a magic constant, so the state isn't zero.
+  uint64_t Hash = MagicHashConstant;
+
+  // Consider instruction opcode in the hash.
+  Hash = hashing::detail::hash_16_bytes(Hash, I->getOpcode());
+
+  // Operand opcodes for further sorting (commutative).
+  SmallVector<int, 4> OperandsOpcodes;
+
+  // Collect operand opcodes for hashing.
+  for (auto &OP : I->operands())
+    if (auto *IOP = dyn_cast<Instruction>(OP))
+      OperandsOpcodes.push_back(IOP->getOpcode());
+
+  if (I->isCommutative())
+    llvm::sort(OperandsOpcodes.begin(), OperandsOpcodes.end());
+
+  // Consider operand opcodes in the hash.
+  for (const int Code : OperandsOpcodes)
+    Hash = hashing::detail::hash_16_bytes(Hash, Code);
+
+  // Base instruction name.
+  SmallString<512> Name;
+  Name.append("op" + std::to_string(Hash).substr(0, 5));
+
+  // In case of CallInst, consider callee in the instruction name.
+  if (const auto *CI = dyn_cast<CallInst>(I))
+    if (const Function *F = CI->getCalledFunction())
+      Name.append(F->getName());
+
+  Name.append("(");
+  for (unsigned long i = 0; i < Operands.size(); ++i) {
+    Name.append(Operands[i]);
+
+    if (i < Operands.size() - 1)
+      Name.append(", ");
+  }
+  Name.append(")");
+
+  if ((I->getName().empty() || RenameAll) && !I->getType()->isVoidTy())
+    I->setName(Name);
+}
+
+/// Shortens instruction's name. This method removes called function name from
+/// the instruction name and substitutes the call chain with a corresponding
+/// list of operands.
+///
+/// Examples:
+/// op00000Callee(op00001Callee(...), vl00000Callee(1, 2), ...)  ->
+/// op00000(op00001, vl00000, ...) vl00000Callee(1, 2)  ->  vl00000(1, 2)
+///
+/// This method omits output instructions and pre-output (instructions directly
+/// used by an output instruction) instructions (by default). By default it also
+/// does not affect user named instructions.
+///
+/// \param I Instruction whose name will be folded.
+void IRCanonicalizer::foldInstructionName(Instruction *I) {
+  // If this flag is raised, fold all regular
+  // instructions (including pre-outputs).
+  if (!FoldPreoutputs) {
+    // Don't fold if one of the users is an output instruction.
+    for (auto *U : I->users())
+      if (auto *IU = dyn_cast<Instruction>(U))
+        if (isOutput(IU))
+          return;
+  }
+
+  // Don't fold if it is an output instruction or has no op prefix.
+  if (isOutput(I) || I->getName().substr(0, 2) != "op")
+    return;
+
+  // Instruction operands.
+  SmallVector<SmallString<64>, 4> Operands;
+
+  for (auto &OP : I->operands()) {
+    if (const Instruction *IOP = dyn_cast<Instruction>(OP)) {
+      bool HasCanonicalName = I->getName().substr(0, 2) == "op" ||
+                              I->getName().substr(0, 2) == "vl";
+
+      Operands.push_back(HasCanonicalName ? IOP->getName().substr(0, 7)
+                                          : IOP->getName());
+    }
+  }
+
+  if (I->isCommutative())
+    llvm::sort(Operands.begin(), Operands.end());
+
+  SmallString<256> Name;
+  Name.append(I->getName().substr(0, 7));
+
+  Name.append("(");
+  for (unsigned long i = 0; i < Operands.size(); ++i) {
+    Name.append(Operands[i]);
+
+    if (i < Operands.size() - 1)
+      Name.append(", ");
+  }
+  Name.append(")");
+
+  I->setName(Name);
+}
+
+/// Reorders instructions by walking up the tree from each operand of an output
+/// instruction and reducing the def-use distance.
+/// This method assumes that output instructions were collected top-down,
+/// otherwise the def-use chain may be broken.
+/// This method is a wrapper for recursive reorderInstruction().
+///
+/// \see reorderInstruction()
+/// \param Outputs Vector of pointers to output instructions collected top-down.
+void IRCanonicalizer::reorderInstructions(
+    SmallVector<Instruction *, 16> &Outputs) {
+  // This method assumes output instructions were collected top-down,
+  // otherwise the def-use chain may be broken.
+
+  SmallPtrSet<const Instruction *, 32> Visited;
+
+  // Walk up the tree.
+  for (auto &I : Outputs)
+    for (auto &OP : I->operands())
+      if (auto *IOP = dyn_cast<Instruction>(OP))
+        reorderInstruction(IOP, I, Visited);
+}
+
+/// Reduces def-use distance or places instruction at the end of the basic
+/// block. Continues to walk up the def-use tree recursively. Used by
+/// reorderInstructions().
+///
+/// \see reorderInstructions()
+/// \param Used Pointer to the instruction whose value is used by the \p User.
+/// \param User Pointer to the instruction which uses the \p Used.
+/// \param Visited Set of visited instructions.
+void IRCanonicalizer::reorderInstruction(
+    Instruction *Used, Instruction *User,
+    SmallPtrSet<const Instruction *, 32> &Visited) {
+
+  if (!Visited.count(Used)) {
+    Visited.insert(Used);
+
+    if (Used->getParent() == User->getParent()) {
+      // If Used and User share the same basic block move Used just before User.
+      Used->moveBefore(User);
+    } else {
+      // Otherwise move Used to the very end of its basic block.
+      Used->moveBefore(&Used->getParent()->back());
+    }
+
+    for (auto &OP : Used->operands()) {
+      if (auto *IOP = dyn_cast<Instruction>(OP)) {
+        // Walk up the def-use tree.
+        reorderInstruction(IOP, Used, Visited);
+      }
+    }
+  }
+}
+
+/// Reorders instruction's operands alphabetically. This method assumes
+/// that passed instruction is commutative. Changing the operand order
+/// in other instructions may change the semantics.
+///
+/// \param I Instruction whose operands will be reordered.
+void IRCanonicalizer::reorderInstructionOperandsByNames(Instruction *I) {
+  // This method assumes that passed I is commutative,
+  // changing the order of operands in other instructions
+  // may change the semantics.
+
+  // Instruction operands for further sorting.
+  SmallVector<std::pair<std::string, Value *>, 4> Operands;
+
+  // Collect operands.
+  for (auto &OP : I->operands()) {
+    if (auto *VOP = dyn_cast<Value>(OP)) {
+      if (isa<Instruction>(VOP)) {
+        // This is an an instruction.
+        Operands.push_back(
+            std::pair<std::string, Value *>(VOP->getName(), VOP));
+      } else {
+        std::string TextRepresentation;
+        raw_string_ostream Stream(TextRepresentation);
+        OP->printAsOperand(Stream, false);
+        Operands.push_back(std::pair<std::string, Value *>(Stream.str(), VOP));
+      }
+    }
+  }
+
+  // Sort operands.
+  llvm::sort(Operands.begin(), Operands.end(), llvm::less_first());
+
+  // Reorder operands.
+  unsigned Position = 0;
+  for (auto &OP : I->operands()) {
+    OP.set(Operands[Position].second);
+    Position++;
+  }
+}
+
+/// Reorders PHI node's values according to the names of corresponding basic
+/// blocks.
+///
+/// \param PN PHI node to canonicalize.
+void IRCanonicalizer::reorderPHIIncomingValues(PHINode *PN) {
+  // Values for further sorting.
+  SmallVector<std::pair<Value *, BasicBlock *>, 2> Values;
+
+  // Collect blocks and corresponding values.
+  for (auto &BB : PN->blocks()) {
+    Value *V = PN->getIncomingValueForBlock(BB);
+    Values.push_back(std::pair<Value *, BasicBlock *>(V, BB));
+  }
+
+  // Sort values according to the name of a basic block.
+  llvm::sort(Values, [](const std::pair<Value *, BasicBlock *> &LHS,
+                        const std::pair<Value *, BasicBlock *> &RHS) {
+    return LHS.second->getName() < RHS.second->getName();
+  });
+
+  // Swap.
+  for (unsigned i = 0; i < Values.size(); ++i) {
+    PN->setIncomingBlock(i, Values[i].second);
+    PN->setIncomingValue(i, Values[i].first);
+  }
+}
+
+/// Returns a vector of output instructions. An output is an instruction which
+/// has side-effects or is ReturnInst. Uses isOutput().
+///
+/// \see isOutput()
+/// \param F Function to collect outputs from.
+SmallVector<Instruction *, 16>
+IRCanonicalizer::collectOutputInstructions(Function &F) {
+  // Output instructions are collected top-down in each function,
+  // any change may break the def-use chain in reordering methods.
+  SmallVector<Instruction *, 16> Outputs;
+
+  for (auto &I : instructions(F))
+    if (isOutput(&I))
+      Outputs.push_back(&I);
+
+  return Outputs;
+}
+
+/// Helper method checking whether the instruction may have side effects or is
+/// ReturnInst.
+///
+/// \param I Considered instruction.
+bool IRCanonicalizer::isOutput(const Instruction *I) {
+  // Outputs are such instructions which may have side effects or is ReturnInst.
+  if (I->mayHaveSideEffects() || isa<ReturnInst>(I))
+    return true;
+
+  return false;
+}
+
+/// Helper method checking whether the instruction has users and only
+/// immediate operands.
+///
+/// \param I Considered instruction.
+bool IRCanonicalizer::isInitialInstruction(const Instruction *I) {
+  // Initial instructions are such instructions whose values are used by
+  // other instructions, yet they only depend on immediate values.
+  return !I->user_empty() && hasOnlyImmediateOperands(I);
+}
+
+/// Helper method checking whether the instruction has only immediate operands.
+///
+/// \param I Considered instruction.
+bool IRCanonicalizer::hasOnlyImmediateOperands(const Instruction *I) {
+  for (const auto &OP : I->operands())
+    if (isa<Instruction>(OP))
+      return false; // Found non-immediate operand (instruction).
+
+  return true;
+}
+
+/// Helper method returning indices (distance from the beginning of the basic
+/// block) of outputs using the \p I (eliminates repetitions). Walks down the
+/// def-use tree recursively.
+///
+/// \param I Considered instruction.
+/// \param Visited Set of visited instructions.
+SetVector<int> IRCanonicalizer::getOutputFootprint(
+    Instruction *I, SmallPtrSet<const Instruction *, 32> &Visited) {
+
+  // Vector containing indexes of outputs (no repetitions),
+  // which use I in the order of walking down the def-use tree.
+  SetVector<int> Outputs;
+
+  if (!Visited.count(I)) {
+    Visited.insert(I);
+
+    if (isOutput(I)) {
+      // Gets output instruction's parent function.
+      Function *Func = I->getParent()->getParent();
+
+      // Finds and inserts the index of the output to the vector.
+      unsigned Count = 0;
+      for (const auto &B : *Func) {
+        for (const auto &E : B) {
+          if (&E == I)
+            Outputs.insert(Count);
+          Count++;
+        }
+      }
+
+      // Returns to the used instruction.
+      return Outputs;
+    }
+
+    for (auto *U : I->users()) {
+      if (auto *UI = dyn_cast<Instruction>(U)) {
+        // Vector for outputs which use UI.
+        SetVector<int> OutputsUsingUI = getOutputFootprint(UI, Visited);
+
+        // Insert the indexes of outputs using UI.
+        Outputs.insert(OutputsUsingUI.begin(), OutputsUsingUI.end());
+      }
+    }
+  }
+
+  // Return to the used instruction.
+  return Outputs;
+}

>From 5dfc7b7a71dff1138a1231c5c5db6069daa9da46 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 12 Aug 2023 15:55:40 -0700
Subject: [PATCH 02/50] Port IRCanonicalizer to new pass manager

---
 .../llvm/Transforms/Utils/IRCanonicalizer.h   | 15 +++++++++++++
 llvm/lib/Passes/PassBuilder.cpp               |  1 +
 llvm/lib/Passes/PassRegistry.def              |  4 ++++
 llvm/lib/Transforms/Utils/IRCanonicalizer.cpp | 22 +++++++++----------
 4 files changed, 30 insertions(+), 12 deletions(-)
 create mode 100644 llvm/include/llvm/Transforms/Utils/IRCanonicalizer.h

diff --git a/llvm/include/llvm/Transforms/Utils/IRCanonicalizer.h b/llvm/include/llvm/Transforms/Utils/IRCanonicalizer.h
new file mode 100644
index 00000000000000..81bfd1bcfd2ad9
--- /dev/null
+++ b/llvm/include/llvm/Transforms/Utils/IRCanonicalizer.h
@@ -0,0 +1,15 @@
+#ifndef LLVM_TRANSFORMS_UTILS_IRCANONICALIZER_H
+#define LLVM_TRANSFORMS_UTILS_IRCANONICALIZER_H
+
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+/// IRCanonicalizer aims to transform LLVM IR into canonical form.
+struct IRCanonicalizerPass : public PassInfoMixin<IRCanonicalizerPass> {
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
+};
+
+} // namespace llvm
+
+#endif // LLVM_TRANSFORMS_UTILS_IRCANONICALIZER_H
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index 51ddb73943b10d..3675f028c63e36 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -274,6 +274,7 @@
 #include "llvm/Transforms/Utils/HelloWorld.h"
 #include "llvm/Transforms/Utils/InjectTLIMappings.h"
 #include "llvm/Transforms/Utils/InstructionNamer.h"
+#include "llvm/Transforms/Utils/IRCanonicalizer.h"
 #include "llvm/Transforms/Utils/LCSSA.h"
 #include "llvm/Transforms/Utils/LibCallsShrinkWrap.h"
 #include "llvm/Transforms/Utils/LoopSimplify.h"
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
index 6864f307e56cf4..e253db921dfe05 100644
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -312,6 +312,10 @@ FUNCTION_PASS("bounds-checking", BoundsCheckingPass())
 FUNCTION_PASS("break-crit-edges", BreakCriticalEdgesPass())
 FUNCTION_PASS("callbr-prepare", CallBrPreparePass())
 FUNCTION_PASS("callsite-splitting", CallSiteSplittingPass())
+FUNCTION_PASS("canon", IRCanonicalizerPass())
+FUNCTION_PASS("consthoist", ConstantHoistingPass())
+FUNCTION_PASS("count-visits", CountVisitsPass())
+FUNCTION_PASS("constraint-elimination", ConstraintEliminationPass())
 FUNCTION_PASS("chr", ControlHeightReductionPass())
 FUNCTION_PASS("codegenprepare", CodeGenPreparePass(TM))
 FUNCTION_PASS("consthoist", ConstantHoistingPass())
diff --git a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
index 58e2dce0b96685..afa3d94e7f55be 100644
--- a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
@@ -28,6 +28,7 @@
 #include "llvm/PassRegistry.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Transforms/Utils.h"
+#include "llvm/Transforms/Utils/IRCanonicalizer.h"
 #include <algorithm>
 #include <vector>
 
@@ -37,10 +38,8 @@ using namespace llvm;
 
 namespace {
 /// IRCanonicalizer aims to transform LLVM IR into canonical form.
-class IRCanonicalizer : public FunctionPass {
+class IRCanonicalizer {
 public:
-  static char ID;
-
   /// \name Canonicalizer flags.
   /// @{
   /// Preserves original order of instructions.
@@ -53,10 +52,7 @@ class IRCanonicalizer : public FunctionPass {
   static cl::opt<bool> ReorderOperands;
   /// @}
 
-  /// Constructor for the IRCanonicalizer.
-  IRCanonicalizer() : FunctionPass(ID) {}
-
-  bool runOnFunction(Function &F) override;
+  bool runOnFunction(Function &F);
 
 private:
   // Random constant for hashing, so the state isn't zero.
@@ -94,11 +90,6 @@ class IRCanonicalizer : public FunctionPass {
 };
 } // namespace
 
-char IRCanonicalizer::ID = 0;
-static RegisterPass<IRCanonicalizer> X("canon", "Canonicalize the IR",
-                                       false /* Only looks at CFG */,
-                                       false /* Analysis Pass */);
-
 cl::opt<bool> IRCanonicalizer::PreserveOrder(
     "preserve-order", cl::Hidden,
     cl::desc("Preserves original instruction order"));
@@ -630,3 +621,10 @@ SetVector<int> IRCanonicalizer::getOutputFootprint(
   // Return to the used instruction.
   return Outputs;
 }
+
+PreservedAnalyses IRCanonicalizerPass::run(Function &F,
+                                           FunctionAnalysisManager &AM) {
+  errs() << F.getName() << "\n";
+  IRCanonicalizer{}.runOnFunction(F);
+  return PreservedAnalyses::all();
+}

>From 48e683bc47b3fe762f1f23fa38c474c4b31e21ae Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 12 Aug 2023 16:06:29 -0700
Subject: [PATCH 03/50] Port doc updates

---
 llvm/docs/Passes.rst       | 12 ++++++++++--
 llvm/docs/ReleaseNotes.rst |  5 ++++-
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/llvm/docs/Passes.rst b/llvm/docs/Passes.rst
index 2edad5cd3c881a..c7423268f25719 100644
--- a/llvm/docs/Passes.rst
+++ b/llvm/docs/Passes.rst
@@ -543,8 +543,16 @@ variables with initializers are marked as internal.
 An interprocedural variant of :ref:`Sparse Conditional Constant Propagation
 <passes-sccp>`.
 
-``jump-threading``: Jump Threading
-----------------------------------
+``-ir-canonicalizer``: Transforms IR into canonical form
+--------------------------------------------------------
+
+This pass aims to transform LLVM Modules into a canonical form by reordering and
+renaming instructions while preserving the same semantics. The canonicalizer makes
+it easier to spot semantic differences while diffing two modules which have undergone
+two different passes.
+
+``-jump-threading``: Jump Threading
+-----------------------------------
 
 Jump threading tries to find distinct threads of control flow running through a
 basic block.  This pass looks at blocks that have multiple predecessors and
diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index 59c0d4dd2376dd..150a43d6afaffb 100644
--- a/llvm/docs/ReleaseNotes.rst
+++ b/llvm/docs/ReleaseNotes.rst
@@ -42,7 +42,10 @@ Non-comprehensive list of changes in this release
    functionality, or simply have a lot to talk about), see the `NOTE` below
    for adding a new subsection.
 
-* ...
+* Added a new IRCanonicalizer pass which aims to transform LLVM modules into
+  a canonical form by reordering and renaming instructions while preserving the
+  same semantics. The canonicalizer makes it easier to spot semantic differences
+  when diffing two modules which have undergone different passes.
 
 Update on required toolchains to build LLVM
 -------------------------------------------

>From 2d0dafe9ccfca6204ec0422c8e0a68b8387c5b21 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 12 Aug 2023 16:29:46 -0700
Subject: [PATCH 04/50] Port tests

---
 .../IRCanonicalizer/naming-arguments.ll       |  7 ++++++
 .../IRCanonicalizer/naming-basic-blocks.ll    |  8 +++++++
 .../IRCanonicalizer/naming-instructions.ll    | 12 ++++++++++
 .../reordering-instructions.ll                | 14 +++++++++++
 .../reordering-phi-node-values.ll             | 24 +++++++++++++++++++
 5 files changed, 65 insertions(+)
 create mode 100644 llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll
 create mode 100644 llvm/test/Transforms/IRCanonicalizer/naming-basic-blocks.ll
 create mode 100644 llvm/test/Transforms/IRCanonicalizer/naming-instructions.ll
 create mode 100644 llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll
 create mode 100644 llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll

diff --git a/llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll b/llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll
new file mode 100644
index 00000000000000..b3f7630abd042f
--- /dev/null
+++ b/llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll
@@ -0,0 +1,7 @@
+; RUN: opt -S -passes=canon < %s | FileCheck %s
+
+; CHECK: @foo(i32 %a0, i32 %a1)
+define i32 @foo(i32, i32) {
+  %tmp = mul i32 %0, %1
+  ret i32 %tmp
+}
diff --git a/llvm/test/Transforms/IRCanonicalizer/naming-basic-blocks.ll b/llvm/test/Transforms/IRCanonicalizer/naming-basic-blocks.ll
new file mode 100644
index 00000000000000..79e526f8efb7ac
--- /dev/null
+++ b/llvm/test/Transforms/IRCanonicalizer/naming-basic-blocks.ll
@@ -0,0 +1,8 @@
+; RUN: opt -S -passes=canon --rename-all < %s | FileCheck %s
+
+define i32 @foo(i32 %a0) {
+; CHECK: bb{{([0-9]{5})}}
+entry:
+  %a = add i32 %a0, 2
+  ret i32 %a
+}
diff --git a/llvm/test/Transforms/IRCanonicalizer/naming-instructions.ll b/llvm/test/Transforms/IRCanonicalizer/naming-instructions.ll
new file mode 100644
index 00000000000000..a22e816f5bf01e
--- /dev/null
+++ b/llvm/test/Transforms/IRCanonicalizer/naming-instructions.ll
@@ -0,0 +1,12 @@
+; RUN: opt -S -passes=canon --rename-all < %s | FileCheck %s
+
+define i32 @foo(i32 %a0) {
+entry:
+; CHECK: %"vl{{([0-9]{5})}}(%a0, 2)"
+  %a = add i32 %a0, 2
+; CHECK: %"op{{([0-9]{5})}}(vl{{([0-9]{5})}})"
+  %b = add i32 %a, 6
+; CHECK: %"op{{([0-9]{5})}}(8, op{{([0-9]{5})}}(6, vl{{([0-9]{5})}}(%a0, 2)))"
+  %c = add i32 %b, 8
+  ret i32 %c
+}
diff --git a/llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll b/llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll
new file mode 100644
index 00000000000000..04660ac73c11bd
--- /dev/null
+++ b/llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll
@@ -0,0 +1,14 @@
+; RUN: opt -S -passes=canon < %s | FileCheck %s
+
+define double @foo(double %a0, double %a1) {
+entry:
+; CHECK: %a
+; CHECK: %c
+; CHECK: %b
+; CHECK: %d
+  %a = fmul double %a0, %a1
+  %b = fmul double %a0, 2.000000e+00
+  %c = fmul double %a, 6.000000e+00
+  %d = fmul double %b, 6.000000e+00
+  ret double %d
+}
diff --git a/llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll b/llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll
new file mode 100644
index 00000000000000..5f344ec29be66f
--- /dev/null
+++ b/llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll
@@ -0,0 +1,24 @@
+; RUN: opt -S -passes=canon < %s | FileCheck %s
+
+declare double @foo()
+
+declare double @bar()
+
+define double @baz(double %x) {
+entry:
+  %ifcond = fcmp one double %x, 0.000000e+00
+  br i1 %ifcond, label %then, label %else
+
+then:       ; preds = %entry
+  %calltmp = call double @foo()
+  br label %ifcont
+
+else:       ; preds = %entry
+  %calltmp1 = call double @bar()
+  br label %ifcont
+
+ifcont:     ; preds = %else, %then
+; CHECK: %iftmp = phi double [ %calltmp1, %else ], [ %calltmp, %then ]
+  %iftmp = phi double [ %calltmp, %then ], [ %calltmp1, %else ]
+  ret double %iftmp
+}

>From f85cfc925ca384393bff46dfab3b885a2ca51b51 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 19 Aug 2023 15:23:09 -0700
Subject: [PATCH 05/50] Turn rename-all and -reorder-operands on by default

---
 llvm/lib/Transforms/Utils/IRCanonicalizer.cpp               | 6 ++++--
 llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll    | 2 +-
 .../Transforms/IRCanonicalizer/reordering-instructions.ll   | 2 +-
 .../IRCanonicalizer/reordering-phi-node-values.ll           | 2 +-
 4 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
index afa3d94e7f55be..b5a007c80b32b3 100644
--- a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
@@ -95,13 +95,15 @@ cl::opt<bool> IRCanonicalizer::PreserveOrder(
     cl::desc("Preserves original instruction order"));
 cl::opt<bool> IRCanonicalizer::RenameAll(
     "rename-all", cl::Hidden,
-    cl::desc("Renames all instructions (including user-named)"));
+    cl::desc("Renames all instructions (including user-named)"), 
+    cl::init(true));
 cl::opt<bool> IRCanonicalizer::FoldPreoutputs(
     "fold-all", cl::Hidden,
     cl::desc("Folds all regular instructions (including pre-outputs)"));
 cl::opt<bool> IRCanonicalizer::ReorderOperands(
     "reorder-operands", cl::Hidden,
-    cl::desc("Sorts and reorders operands in commutative instructions"));
+    cl::desc("Sorts and reorders operands in commutative instructions"),
+    cl::init(true));
 
 /// Entry method to the IRCanonicalizer.
 ///
diff --git a/llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll b/llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll
index b3f7630abd042f..5a274f7cc5a3b7 100644
--- a/llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll
+++ b/llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=canon < %s | FileCheck %s
+; RUN: opt -S -passes=canon --rename-all=false < %s | FileCheck %s
 
 ; CHECK: @foo(i32 %a0, i32 %a1)
 define i32 @foo(i32, i32) {
diff --git a/llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll b/llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll
index 04660ac73c11bd..3ea19e8b6c78c9 100644
--- a/llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll
+++ b/llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=canon < %s | FileCheck %s
+; RUN: opt -S -passes=canon --rename-all=false < %s | FileCheck %s
 
 define double @foo(double %a0, double %a1) {
 entry:
diff --git a/llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll b/llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll
index 5f344ec29be66f..3ea0bab50b5b9a 100644
--- a/llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll
+++ b/llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=canon < %s | FileCheck %s
+; RUN: opt -S -passes=canon --rename-all=false < %s | FileCheck %s
 
 declare double @foo()
 

>From 0df9f96c2161acc945206184380bf75f21f30fea Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 19 Aug 2023 15:25:12 -0700
Subject: [PATCH 06/50] Add infinite loop regression test

---
 .../IRCanonicalizer/infinite-loop.ll          | 100 ++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 llvm/test/Transforms/IRCanonicalizer/infinite-loop.ll

diff --git a/llvm/test/Transforms/IRCanonicalizer/infinite-loop.ll b/llvm/test/Transforms/IRCanonicalizer/infinite-loop.ll
new file mode 100644
index 00000000000000..f67c1eb7fa5b22
--- /dev/null
+++ b/llvm/test/Transforms/IRCanonicalizer/infinite-loop.ll
@@ -0,0 +1,100 @@
+; RUN: opt -passes=canon < %s
+
+; XFAIL: *
+; FIXME: Infinite loop in name instructions
+
+define void @test(ptr) {
+bb:
+  br label %bb1
+
+bb1:                                              ; preds = %bb1, %bb
+  %tmp = phi i32 [ undef, %bb ], [ %tmp87, %bb1 ]
+  %tmp2 = phi i32 [ undef, %bb ], [ %tmp86, %bb1 ]
+  %tmp3 = mul i32 %tmp, undef
+  %tmp4 = xor i32 %tmp3, -1
+  %tmp5 = add i32 %tmp, %tmp4
+  %tmp6 = add i32 %tmp2, -1
+  %tmp7 = add i32 %tmp5, %tmp6
+  %tmp8 = mul i32 %tmp7, %tmp3
+  %tmp9 = xor i32 %tmp8, -1
+  %tmp10 = add i32 %tmp7, %tmp9
+  %tmp11 = add i32 %tmp10, undef
+  %tmp12 = mul i32 %tmp11, %tmp8
+  %tmp13 = xor i32 %tmp12, -1
+  %tmp14 = add i32 %tmp11, %tmp13
+  %tmp15 = add i32 %tmp14, undef
+  %tmp16 = mul i32 %tmp15, %tmp12
+  %tmp17 = add i32 %tmp15, undef
+  %tmp18 = add i32 %tmp17, undef
+  %tmp19 = mul i32 %tmp18, %tmp16
+  %tmp20 = xor i32 %tmp19, -1
+  %tmp21 = add i32 %tmp18, %tmp20
+  %tmp22 = add i32 %tmp21, undef
+  %tmp23 = mul i32 %tmp22, %tmp19
+  %tmp24 = xor i32 %tmp23, -1
+  %tmp25 = add i32 %tmp22, %tmp24
+  %tmp26 = add i32 %tmp25, undef
+  %tmp27 = mul i32 %tmp26, %tmp23
+  %tmp28 = xor i32 %tmp27, -1
+  %tmp29 = add i32 %tmp26, %tmp28
+  %tmp30 = add i32 %tmp29, undef
+  %tmp31 = mul i32 %tmp30, %tmp27
+  %tmp32 = xor i32 %tmp31, -1
+  %tmp33 = add i32 %tmp30, %tmp32
+  %tmp34 = add i32 %tmp33, undef
+  %tmp35 = mul i32 %tmp34, %tmp31
+  %tmp36 = xor i32 %tmp35, -1
+  %tmp37 = add i32 %tmp34, %tmp36
+  %tmp38 = add i32 %tmp2, -9
+  %tmp39 = add i32 %tmp37, %tmp38
+  %tmp40 = mul i32 %tmp39, %tmp35
+  %tmp41 = xor i32 %tmp40, -1
+  %tmp42 = add i32 %tmp39, %tmp41
+  %tmp43 = add i32 %tmp42, undef
+  %tmp44 = mul i32 %tmp43, %tmp40
+  %tmp45 = xor i32 %tmp44, -1
+  %tmp46 = add i32 %tmp43, %tmp45
+  %tmp47 = add i32 %tmp46, undef
+  %tmp48 = mul i32 %tmp47, %tmp44
+  %tmp49 = xor i32 %tmp48, -1
+  %tmp50 = add i32 %tmp47, %tmp49
+  %tmp51 = add i32 %tmp50, undef
+  %tmp52 = mul i32 %tmp51, %tmp48
+  %tmp53 = xor i32 %tmp52, -1
+  %tmp54 = add i32 %tmp51, %tmp53
+  %tmp55 = add i32 %tmp54, undef
+  %tmp56 = mul i32 %tmp55, %tmp52
+  %tmp57 = xor i32 %tmp56, -1
+  %tmp58 = add i32 %tmp55, %tmp57
+  %tmp59 = add i32 %tmp2, -14
+  %tmp60 = add i32 %tmp58, %tmp59
+  %tmp61 = mul i32 %tmp60, %tmp56
+  %tmp62 = xor i32 %tmp61, -1
+  %tmp63 = add i32 %tmp60, %tmp62
+  %tmp64 = add i32 %tmp63, undef
+  %tmp65 = mul i32 %tmp64, %tmp61
+  %tmp66 = xor i32 %tmp65, -1
+  %tmp67 = add i32 %tmp64, %tmp66
+  %tmp68 = add i32 %tmp67, undef
+  %tmp69 = mul i32 %tmp68, %tmp65
+  %tmp70 = xor i32 %tmp69, -1
+  %tmp71 = add i32 %tmp68, %tmp70
+  %tmp72 = add i32 %tmp71, undef
+  %tmp73 = mul i32 %tmp72, %tmp69
+  %tmp74 = xor i32 %tmp73, -1
+  %tmp75 = add i32 %tmp72, %tmp74
+  %tmp76 = add i32 %tmp75, undef
+  %tmp77 = mul i32 %tmp76, %tmp73
+  %tmp78 = xor i32 %tmp77, -1
+  %tmp79 = add i32 %tmp76, %tmp78
+  %tmp80 = add i32 %tmp79, undef
+  %tmp81 = mul i32 %tmp80, %tmp77
+  %tmp82 = xor i32 %tmp81, -1
+  %tmp83 = add i32 %tmp80, %tmp82
+  %tmp84 = add i32 %tmp83, undef
+  %tmp85 = add i32 %tmp84, undef
+  %tmp86 = add i32 %tmp2, -21
+  %tmp87 = add i32 %tmp85, %tmp86
+  store i32 %tmp87, ptr %0
+  br label %bb1
+}

>From e26090b9ea48bd5c297a7ac266e320fb4c5a6ca2 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sun, 27 Aug 2023 15:19:36 -0700
Subject: [PATCH 07/50] Add visited set to fix infinite loop bug

---
 llvm/lib/Transforms/Utils/IRCanonicalizer.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
index b5a007c80b32b3..73433a9a05c0d4 100644
--- a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
@@ -57,6 +57,7 @@ class IRCanonicalizer {
 private:
   // Random constant for hashing, so the state isn't zero.
   const uint64_t MagicHashConstant = 0x6acaa36bef8325c5ULL;
+  DenseSet<const Instruction *> NamedInstructions;
 
   /// \name Naming.
   /// @{
@@ -175,6 +176,9 @@ void IRCanonicalizer::nameBasicBlocks(Function &F) {
 ///
 /// \param I Instruction to be renamed.
 void IRCanonicalizer::nameInstruction(Instruction *I) {
+  if (NamedInstructions.contains(I))
+    return;
+  NamedInstructions.insert(I); 
   // Determine the type of instruction to name.
   if (isInitialInstruction(I)) {
     // This is an initial instruction.

>From 134a6ddfe02e918716508d7ce2e92d82e227259e Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sun, 27 Aug 2023 15:20:12 -0700
Subject: [PATCH 08/50] Expand test to expose reordering bug

---
 .../Transforms/IRCanonicalizer/infinite-loop.ll     | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/llvm/test/Transforms/IRCanonicalizer/infinite-loop.ll b/llvm/test/Transforms/IRCanonicalizer/infinite-loop.ll
index f67c1eb7fa5b22..3438a05b4aee48 100644
--- a/llvm/test/Transforms/IRCanonicalizer/infinite-loop.ll
+++ b/llvm/test/Transforms/IRCanonicalizer/infinite-loop.ll
@@ -1,15 +1,14 @@
-; RUN: opt -passes=canon < %s
+; RUN: opt -passes=canon -preserve-order=true < %s
+; RUN: opt -passes=canon -preserve-order=false < %s
 
-; XFAIL: *
-; FIXME: Infinite loop in name instructions
-
-define void @test(ptr) {
+define void @test(ptr, i32) {
 bb:
+  %a = add i32 %1, 1
   br label %bb1
 
 bb1:                                              ; preds = %bb1, %bb
-  %tmp = phi i32 [ undef, %bb ], [ %tmp87, %bb1 ]
-  %tmp2 = phi i32 [ undef, %bb ], [ %tmp86, %bb1 ]
+  %tmp = phi i32 [ %a, %bb ], [ %tmp87, %bb1 ]
+  %tmp2 = phi i32 [ %a, %bb ], [ %tmp86, %bb1 ]
   %tmp3 = mul i32 %tmp, undef
   %tmp4 = xor i32 %tmp3, -1
   %tmp5 = add i32 %tmp, %tmp4

>From 4dad5dec05bd0c7c20e3c842c483f3c92a2dc138 Mon Sep 17 00:00:00 2001
From: Aidan <aidan.goldfarb at mail.mcgill.ca>
Date: Mon, 28 Aug 2023 12:28:20 -0400
Subject: [PATCH 09/50] added some documentation

---
 llvm/lib/Transforms/Utils/IRCanonicalizer.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
index 73433a9a05c0d4..600c2baf6e013a 100644
--- a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
@@ -176,6 +176,9 @@ void IRCanonicalizer::nameBasicBlocks(Function &F) {
 ///
 /// \param I Instruction to be renamed.
 void IRCanonicalizer::nameInstruction(Instruction *I) {
+  //ensure instructions are not renamed. This is done
+  //to prevent situation where instructions are used
+  //before their definition (in phi nodes)
   if (NamedInstructions.contains(I))
     return;
   NamedInstructions.insert(I); 

>From 21f961c99170af46d74c101e1d95a2dd615be84e Mon Sep 17 00:00:00 2001
From: Aidan <aidan.goldfarb at mail.mcgill.ca>
Date: Mon, 28 Aug 2023 13:56:05 -0400
Subject: [PATCH 10/50] pushed broken int test

---
 .../IRCanonicalizer/naming-args-instr-blocks.ll   | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 llvm/test/Transforms/IRCanonicalizer/naming-args-instr-blocks.ll

diff --git a/llvm/test/Transforms/IRCanonicalizer/naming-args-instr-blocks.ll b/llvm/test/Transforms/IRCanonicalizer/naming-args-instr-blocks.ll
new file mode 100644
index 00000000000000..74e1944825011b
--- /dev/null
+++ b/llvm/test/Transforms/IRCanonicalizer/naming-args-instr-blocks.ll
@@ -0,0 +1,15 @@
+; RUN: opt -S -passes=canon --rename-all --preserve-order < %s | FileCheck %s
+
+
+; CHECK: @foo(i32 %a0)
+define i32 @foo(i32) {
+; CHECK: bb{{([0-9]{5})}}
+entry:
+    ; CHECK: %"vl{{([0-9]{5})}}(%a0, 2)"
+    %a = add i32 %0, 2
+    
+    ; CHECK: %"op{{([0-9]{5})}}(vl{{([0-9]{5})}})"
+    %b = add i32 %a, 6
+
+    ret i32 %a
+}

>From f1d24f055543ccb8bb1467c2c2b4f8170d9865f8 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Mon, 11 Sep 2023 12:27:35 -0700
Subject: [PATCH 11/50] Reformat `reorderInstruction`

---
 llvm/lib/Transforms/Utils/IRCanonicalizer.cpp | 30 +++++++++----------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
index 600c2baf6e013a..6f60d3d261d828 100644
--- a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
@@ -443,23 +443,23 @@ void IRCanonicalizer::reorderInstructions(
 void IRCanonicalizer::reorderInstruction(
     Instruction *Used, Instruction *User,
     SmallPtrSet<const Instruction *, 32> &Visited) {
+  if (Visited.contains(Used)) {
+    return;
+  }
+  Visited.insert(Used);
 
-  if (!Visited.count(Used)) {
-    Visited.insert(Used);
-
-    if (Used->getParent() == User->getParent()) {
-      // If Used and User share the same basic block move Used just before User.
-      Used->moveBefore(User);
-    } else {
-      // Otherwise move Used to the very end of its basic block.
-      Used->moveBefore(&Used->getParent()->back());
-    }
+  if (Used->getParent() == User->getParent()) {
+    // If Used and User share the same basic block move Used just before User.
+    Used->moveBefore(User);
+  } else {
+    // Otherwise move Used to the very end of its basic block.
+    Used->moveBefore(&Used->getParent()->back());
+  }
 
-    for (auto &OP : Used->operands()) {
-      if (auto *IOP = dyn_cast<Instruction>(OP)) {
-        // Walk up the def-use tree.
-        reorderInstruction(IOP, Used, Visited);
-      }
+  for (auto &OP : Used->operands()) {
+    if (auto *IOP = dyn_cast<Instruction>(OP)) {
+      // Walk up the def-use tree.
+      reorderInstruction(IOP, Used, Visited);
     }
   }
 }

>From 908740797a645cdfd8f35d54168eba56a3b328af Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Mon, 11 Sep 2023 13:05:30 -0700
Subject: [PATCH 12/50] Bug fix: don't reorder PHI nodes

---
 llvm/lib/Transforms/Utils/IRCanonicalizer.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
index 6f60d3d261d828..a40435f7b82293 100644
--- a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
@@ -443,9 +443,10 @@ void IRCanonicalizer::reorderInstructions(
 void IRCanonicalizer::reorderInstruction(
     Instruction *Used, Instruction *User,
     SmallPtrSet<const Instruction *, 32> &Visited) {
-  if (Visited.contains(Used)) {
+  if(isa<PHINode>(Used))
+    return;
+  if (Visited.contains(Used))
     return;
-  }
   Visited.insert(Used);
 
   if (Used->getParent() == User->getParent()) {

>From d519d353dc9a86536d4202ed81290ab90a9047b4 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Mon, 11 Sep 2023 13:29:27 -0700
Subject: [PATCH 13/50] Revert "Turn rename-all and -reorder-operands on by
 default"

This reverts commit f5b7445662310a2f329e0f4aaf45822058f307ba.
---
 llvm/lib/Transforms/Utils/IRCanonicalizer.cpp               | 6 ++----
 llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll    | 2 +-
 .../Transforms/IRCanonicalizer/reordering-instructions.ll   | 2 +-
 .../IRCanonicalizer/reordering-phi-node-values.ll           | 2 +-
 4 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
index a40435f7b82293..45dc954f97b9c7 100644
--- a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
@@ -96,15 +96,13 @@ cl::opt<bool> IRCanonicalizer::PreserveOrder(
     cl::desc("Preserves original instruction order"));
 cl::opt<bool> IRCanonicalizer::RenameAll(
     "rename-all", cl::Hidden,
-    cl::desc("Renames all instructions (including user-named)"), 
-    cl::init(true));
+    cl::desc("Renames all instructions (including user-named)"));
 cl::opt<bool> IRCanonicalizer::FoldPreoutputs(
     "fold-all", cl::Hidden,
     cl::desc("Folds all regular instructions (including pre-outputs)"));
 cl::opt<bool> IRCanonicalizer::ReorderOperands(
     "reorder-operands", cl::Hidden,
-    cl::desc("Sorts and reorders operands in commutative instructions"),
-    cl::init(true));
+    cl::desc("Sorts and reorders operands in commutative instructions"));
 
 /// Entry method to the IRCanonicalizer.
 ///
diff --git a/llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll b/llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll
index 5a274f7cc5a3b7..b3f7630abd042f 100644
--- a/llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll
+++ b/llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=canon --rename-all=false < %s | FileCheck %s
+; RUN: opt -S -passes=canon < %s | FileCheck %s
 
 ; CHECK: @foo(i32 %a0, i32 %a1)
 define i32 @foo(i32, i32) {
diff --git a/llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll b/llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll
index 3ea19e8b6c78c9..04660ac73c11bd 100644
--- a/llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll
+++ b/llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=canon --rename-all=false < %s | FileCheck %s
+; RUN: opt -S -passes=canon < %s | FileCheck %s
 
 define double @foo(double %a0, double %a1) {
 entry:
diff --git a/llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll b/llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll
index 3ea0bab50b5b9a..5f344ec29be66f 100644
--- a/llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll
+++ b/llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=canon --rename-all=false < %s | FileCheck %s
+; RUN: opt -S -passes=canon < %s | FileCheck %s
 
 declare double @foo()
 

>From fddfbba8824a522de0ac2a791c3abea7b2b265c4 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Mon, 25 Sep 2023 11:13:25 -0500
Subject: [PATCH 14/50] Fix naming-args-instr-blocks.ll

---
 .../Transforms/IRCanonicalizer/naming-args-instr-blocks.ll    | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/test/Transforms/IRCanonicalizer/naming-args-instr-blocks.ll b/llvm/test/Transforms/IRCanonicalizer/naming-args-instr-blocks.ll
index 74e1944825011b..605c62863f2ad3 100644
--- a/llvm/test/Transforms/IRCanonicalizer/naming-args-instr-blocks.ll
+++ b/llvm/test/Transforms/IRCanonicalizer/naming-args-instr-blocks.ll
@@ -8,8 +8,8 @@ entry:
     ; CHECK: %"vl{{([0-9]{5})}}(%a0, 2)"
     %a = add i32 %0, 2
     
-    ; CHECK: %"op{{([0-9]{5})}}(vl{{([0-9]{5})}})"
+    ; CHECK: %"op{{([0-9]{5})}}(6, vl{{([0-9]{5})}}(%a0, 2))"
     %b = add i32 %a, 6
 
-    ret i32 %a
+    ret i32 %b
 }

>From 94192038150c33793a4ad035040652a512c3fd37 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Tue, 3 Oct 2023 21:55:04 -0700
Subject: [PATCH 15/50] clang format changes

---
 llvm/lib/Passes/PassBuilder.cpp               |  2 +-
 llvm/lib/Transforms/Utils/IRCanonicalizer.cpp | 12 ++++++------
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index 3675f028c63e36..4a5bccfe35d312 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -272,9 +272,9 @@
 #include "llvm/Transforms/Utils/EntryExitInstrumenter.h"
 #include "llvm/Transforms/Utils/FixIrreducible.h"
 #include "llvm/Transforms/Utils/HelloWorld.h"
+#include "llvm/Transforms/Utils/IRCanonicalizer.h"
 #include "llvm/Transforms/Utils/InjectTLIMappings.h"
 #include "llvm/Transforms/Utils/InstructionNamer.h"
-#include "llvm/Transforms/Utils/IRCanonicalizer.h"
 #include "llvm/Transforms/Utils/LCSSA.h"
 #include "llvm/Transforms/Utils/LibCallsShrinkWrap.h"
 #include "llvm/Transforms/Utils/LoopSimplify.h"
diff --git a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
index 45dc954f97b9c7..7ea3959e5e90d0 100644
--- a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
@@ -174,12 +174,12 @@ void IRCanonicalizer::nameBasicBlocks(Function &F) {
 ///
 /// \param I Instruction to be renamed.
 void IRCanonicalizer::nameInstruction(Instruction *I) {
-  //ensure instructions are not renamed. This is done
-  //to prevent situation where instructions are used
-  //before their definition (in phi nodes)
+  // Ensure instructions are not renamed. This is done
+  // to prevent situation where instructions are used
+  // before their definition (in phi nodes)
   if (NamedInstructions.contains(I))
     return;
-  NamedInstructions.insert(I); 
+  NamedInstructions.insert(I);
   // Determine the type of instruction to name.
   if (isInitialInstruction(I)) {
     // This is an initial instruction.
@@ -381,7 +381,7 @@ void IRCanonicalizer::foldInstructionName(Instruction *I) {
   SmallVector<SmallString<64>, 4> Operands;
 
   for (auto &OP : I->operands()) {
-    if (const Instruction *IOP = dyn_cast<Instruction>(OP)) {
+    if (const auto *IOP = dyn_cast<Instruction>(OP)) {
       bool HasCanonicalName = I->getName().substr(0, 2) == "op" ||
                               I->getName().substr(0, 2) == "vl";
 
@@ -441,7 +441,7 @@ void IRCanonicalizer::reorderInstructions(
 void IRCanonicalizer::reorderInstruction(
     Instruction *Used, Instruction *User,
     SmallPtrSet<const Instruction *, 32> &Visited) {
-  if(isa<PHINode>(Used))
+  if (isa<PHINode>(Used))
     return;
   if (Visited.contains(Used))
     return;

>From e82f8056ebc27b3de4f5319d9bcb84155dcaa16a Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Wed, 4 Oct 2023 08:12:40 -0700
Subject: [PATCH 16/50] clang-format changes

---
 llvm/lib/Transforms/Utils/IRCanonicalizer.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
index 7ea3959e5e90d0..c12595ba48a3f7 100644
--- a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
@@ -14,6 +14,7 @@
 ///
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Transforms/Utils/IRCanonicalizer.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallString.h"
@@ -28,7 +29,6 @@
 #include "llvm/PassRegistry.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Transforms/Utils.h"
-#include "llvm/Transforms/Utils/IRCanonicalizer.h"
 #include <algorithm>
 #include <vector>
 

>From de45a07d5242c7ba544ecafbbc20e3e831c73935 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 14 Oct 2023 18:04:58 -0400
Subject: [PATCH 17/50] Rename to IRNormalizer

---
 llvm/docs/Passes.rst                          |  2 +-
 llvm/docs/ReleaseNotes.rst                    |  2 +-
 .../llvm/Transforms/Utils/IRCanonicalizer.h   | 15 -----
 .../llvm/Transforms/Utils/IRNormalizer.h      | 15 +++++
 llvm/lib/Passes/PassBuilder.cpp               |  2 +-
 llvm/lib/Passes/PassRegistry.def              | 12 +++-
 llvm/lib/Transforms/Utils/CMakeLists.txt      |  2 +-
 .../{IRCanonicalizer.cpp => IRNormalizer.cpp} | 60 +++++++++----------
 .../infinite-loop.ll                          |  4 +-
 .../naming-args-instr-blocks.ll               |  2 +-
 .../naming-arguments.ll                       |  2 +-
 .../naming-basic-blocks.ll                    |  2 +-
 .../naming-instructions.ll                    |  2 +-
 .../reordering-instructions.ll                |  2 +-
 .../reordering-phi-node-values.ll             |  2 +-
 15 files changed, 67 insertions(+), 59 deletions(-)
 delete mode 100644 llvm/include/llvm/Transforms/Utils/IRCanonicalizer.h
 create mode 100644 llvm/include/llvm/Transforms/Utils/IRNormalizer.h
 rename llvm/lib/Transforms/Utils/{IRCanonicalizer.cpp => IRNormalizer.cpp} (92%)
 rename llvm/test/Transforms/{IRCanonicalizer => IRNormalizer}/infinite-loop.ll (96%)
 rename llvm/test/Transforms/{IRCanonicalizer => IRNormalizer}/naming-args-instr-blocks.ll (75%)
 rename llvm/test/Transforms/{IRCanonicalizer => IRNormalizer}/naming-arguments.ll (66%)
 rename llvm/test/Transforms/{IRCanonicalizer => IRNormalizer}/naming-basic-blocks.ll (60%)
 rename llvm/test/Transforms/{IRCanonicalizer => IRNormalizer}/naming-instructions.ll (80%)
 rename llvm/test/Transforms/{IRCanonicalizer => IRNormalizer}/reordering-instructions.ll (83%)
 rename llvm/test/Transforms/{IRCanonicalizer => IRNormalizer}/reordering-phi-node-values.ll (91%)

diff --git a/llvm/docs/Passes.rst b/llvm/docs/Passes.rst
index c7423268f25719..250002a65fecaf 100644
--- a/llvm/docs/Passes.rst
+++ b/llvm/docs/Passes.rst
@@ -543,7 +543,7 @@ variables with initializers are marked as internal.
 An interprocedural variant of :ref:`Sparse Conditional Constant Propagation
 <passes-sccp>`.
 
-``-ir-canonicalizer``: Transforms IR into canonical form
+``ir-normalizer``: Transforms IR into a canonical form that's easier to diff
 --------------------------------------------------------
 
 This pass aims to transform LLVM Modules into a canonical form by reordering and
diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index 150a43d6afaffb..6786abaee73645 100644
--- a/llvm/docs/ReleaseNotes.rst
+++ b/llvm/docs/ReleaseNotes.rst
@@ -42,7 +42,7 @@ Non-comprehensive list of changes in this release
    functionality, or simply have a lot to talk about), see the `NOTE` below
    for adding a new subsection.
 
-* Added a new IRCanonicalizer pass which aims to transform LLVM modules into
+* Added a new IRNormalizer pass which aims to transform LLVM modules into
   a canonical form by reordering and renaming instructions while preserving the
   same semantics. The canonicalizer makes it easier to spot semantic differences
   when diffing two modules which have undergone different passes.
diff --git a/llvm/include/llvm/Transforms/Utils/IRCanonicalizer.h b/llvm/include/llvm/Transforms/Utils/IRCanonicalizer.h
deleted file mode 100644
index 81bfd1bcfd2ad9..00000000000000
--- a/llvm/include/llvm/Transforms/Utils/IRCanonicalizer.h
+++ /dev/null
@@ -1,15 +0,0 @@
-#ifndef LLVM_TRANSFORMS_UTILS_IRCANONICALIZER_H
-#define LLVM_TRANSFORMS_UTILS_IRCANONICALIZER_H
-
-#include "llvm/IR/PassManager.h"
-
-namespace llvm {
-
-/// IRCanonicalizer aims to transform LLVM IR into canonical form.
-struct IRCanonicalizerPass : public PassInfoMixin<IRCanonicalizerPass> {
-  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
-};
-
-} // namespace llvm
-
-#endif // LLVM_TRANSFORMS_UTILS_IRCANONICALIZER_H
diff --git a/llvm/include/llvm/Transforms/Utils/IRNormalizer.h b/llvm/include/llvm/Transforms/Utils/IRNormalizer.h
new file mode 100644
index 00000000000000..2e3e23340bc5bc
--- /dev/null
+++ b/llvm/include/llvm/Transforms/Utils/IRNormalizer.h
@@ -0,0 +1,15 @@
+#ifndef LLVM_TRANSFORMS_UTILS_IRNORMALIZER_H
+#define LLVM_TRANSFORMS_UTILS_IRNORMALIZER_H
+
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+/// IRNormalizer aims to transform LLVM IR into canonical form.
+struct IRNormalizerPass : public PassInfoMixin<IRNormalizerPass> {
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
+};
+
+} // namespace llvm
+
+#endif // LLVM_TRANSFORMS_UTILS_IRNORMALIZER_H
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index 4a5bccfe35d312..67ef3a41aa238a 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -272,7 +272,7 @@
 #include "llvm/Transforms/Utils/EntryExitInstrumenter.h"
 #include "llvm/Transforms/Utils/FixIrreducible.h"
 #include "llvm/Transforms/Utils/HelloWorld.h"
-#include "llvm/Transforms/Utils/IRCanonicalizer.h"
+#include "llvm/Transforms/Utils/IRNormalizer.h"
 #include "llvm/Transforms/Utils/InjectTLIMappings.h"
 #include "llvm/Transforms/Utils/InstructionNamer.h"
 #include "llvm/Transforms/Utils/LCSSA.h"
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
index e253db921dfe05..b90729efb2b7b3 100644
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -312,7 +312,6 @@ FUNCTION_PASS("bounds-checking", BoundsCheckingPass())
 FUNCTION_PASS("break-crit-edges", BreakCriticalEdgesPass())
 FUNCTION_PASS("callbr-prepare", CallBrPreparePass())
 FUNCTION_PASS("callsite-splitting", CallSiteSplittingPass())
-FUNCTION_PASS("canon", IRCanonicalizerPass())
 FUNCTION_PASS("consthoist", ConstantHoistingPass())
 FUNCTION_PASS("count-visits", CountVisitsPass())
 FUNCTION_PASS("constraint-elimination", ConstraintEliminationPass())
@@ -388,7 +387,16 @@ FUNCTION_PASS("mergereturn", UnifyFunctionExitNodesPass())
 FUNCTION_PASS("move-auto-init", MoveAutoInitPass())
 FUNCTION_PASS("nary-reassociate", NaryReassociatePass())
 FUNCTION_PASS("newgvn", NewGVNPass())
-FUNCTION_PASS("no-op-function", NoOpFunctionPass())
+FUNCTION_PASS("normalize", IRNormalizerPass())
+FUNCTION_PASS("jump-threading", JumpThreadingPass())
+FUNCTION_PASS("partially-inline-libcalls", PartiallyInlineLibCallsPass())
+FUNCTION_PASS("kcfi", KCFIPass())
+FUNCTION_PASS("lcssa", LCSSAPass())
+FUNCTION_PASS("loop-data-prefetch", LoopDataPrefetchPass())
+FUNCTION_PASS("loop-load-elim", LoopLoadEliminationPass())
+FUNCTION_PASS("loop-fusion", LoopFusePass())
+FUNCTION_PASS("loop-distribute", LoopDistributePass())
+FUNCTION_PASS("loop-versioning", LoopVersioningPass())
 FUNCTION_PASS("objc-arc", ObjCARCOptPass())
 FUNCTION_PASS("objc-arc-contract", ObjCARCContractPass())
 FUNCTION_PASS("objc-arc-expand", ObjCARCExpandPass())
diff --git a/llvm/lib/Transforms/Utils/CMakeLists.txt b/llvm/lib/Transforms/Utils/CMakeLists.txt
index 3e9aae240269eb..ae30a1ea5a5898 100644
--- a/llvm/lib/Transforms/Utils/CMakeLists.txt
+++ b/llvm/lib/Transforms/Utils/CMakeLists.txt
@@ -35,7 +35,7 @@ add_llvm_component_library(LLVMTransformUtils
   InjectTLIMappings.cpp
   InstructionNamer.cpp
   IntegerDivision.cpp
-  IRCanonicalizer.cpp
+  IRNormalizer.cpp
   LCSSA.cpp
   LibCallsShrinkWrap.cpp
   Local.cpp
diff --git a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
similarity index 92%
rename from llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
rename to llvm/lib/Transforms/Utils/IRNormalizer.cpp
index c12595ba48a3f7..da2cbc41346d01 100644
--- a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -1,4 +1,4 @@
-//===--------------- IRCanonicalizer.cpp - IR Canonicalizer ---------------===//
+//===--------------- IRNormalizer.cpp - IR Canonicalizer ---------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -6,15 +6,15 @@
 //
 //===----------------------------------------------------------------------===//
 /// \file
-/// This file implements the IRCanonicalizer class which aims to transform LLVM
+/// This file implements the IRNormalizer class which aims to transform LLVM
 /// Modules into a canonical form by reordering and renaming instructions while
-/// preserving the same semantics. The canonicalizer makes it easier to spot
+/// preserving the same semantics. The normalizer makes it easier to spot
 /// semantic differences while diffing two modules which have undergone
 /// different passes.
 ///
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Transforms/Utils/IRCanonicalizer.h"
+#include "llvm/Transforms/Utils/IRNormalizer.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallString.h"
@@ -32,13 +32,13 @@
 #include <algorithm>
 #include <vector>
 
-#define DEBUG_TYPE "canon"
+#define DEBUG_TYPE "normalize"
 
 using namespace llvm;
 
 namespace {
-/// IRCanonicalizer aims to transform LLVM IR into canonical form.
-class IRCanonicalizer {
+/// IRNormalizer aims to transform LLVM IR into canonical form.
+class IRNormalizer {
 public:
   /// \name Canonicalizer flags.
   /// @{
@@ -91,23 +91,23 @@ class IRCanonicalizer {
 };
 } // namespace
 
-cl::opt<bool> IRCanonicalizer::PreserveOrder(
+cl::opt<bool> IRNormalizer::PreserveOrder(
     "preserve-order", cl::Hidden,
     cl::desc("Preserves original instruction order"));
-cl::opt<bool> IRCanonicalizer::RenameAll(
+cl::opt<bool> IRNormalizer::RenameAll(
     "rename-all", cl::Hidden,
     cl::desc("Renames all instructions (including user-named)"));
-cl::opt<bool> IRCanonicalizer::FoldPreoutputs(
+cl::opt<bool> IRNormalizer::FoldPreoutputs(
     "fold-all", cl::Hidden,
     cl::desc("Folds all regular instructions (including pre-outputs)"));
-cl::opt<bool> IRCanonicalizer::ReorderOperands(
+cl::opt<bool> IRNormalizer::ReorderOperands(
     "reorder-operands", cl::Hidden,
     cl::desc("Sorts and reorders operands in commutative instructions"));
 
-/// Entry method to the IRCanonicalizer.
+/// Entry method to the IRNormalizer.
 ///
 /// \param M Module to canonicalize.
-bool IRCanonicalizer::runOnFunction(Function &F) {
+bool IRNormalizer::runOnFunction(Function &F) {
   nameFunctionArguments(F);
   nameBasicBlocks(F);
 
@@ -137,7 +137,7 @@ bool IRCanonicalizer::runOnFunction(Function &F) {
 /// Numbers arguments.
 ///
 /// \param F Function whose arguments will be renamed.
-void IRCanonicalizer::nameFunctionArguments(Function &F) {
+void IRNormalizer::nameFunctionArguments(Function &F) {
   int ArgumentCounter = 0;
   for (auto &A : F.args()) {
     if (RenameAll || A.getName().empty()) {
@@ -151,7 +151,7 @@ void IRCanonicalizer::nameFunctionArguments(Function &F) {
 /// a function considering the opcode and the order of output instructions.
 ///
 /// \param F Function containing basic blocks to rename.
-void IRCanonicalizer::nameBasicBlocks(Function &F) {
+void IRNormalizer::nameBasicBlocks(Function &F) {
   for (auto &B : F) {
     // Initialize to a magic constant, so the state isn't zero.
     uint64_t Hash = MagicHashConstant;
@@ -173,7 +173,7 @@ void IRCanonicalizer::nameBasicBlocks(Function &F) {
 /// the output (top-most user) instructions (depth-first).
 ///
 /// \param I Instruction to be renamed.
-void IRCanonicalizer::nameInstruction(Instruction *I) {
+void IRNormalizer::nameInstruction(Instruction *I) {
   // Ensure instructions are not renamed. This is done
   // to prevent situation where instructions are used
   // before their definition (in phi nodes)
@@ -203,7 +203,7 @@ void IRCanonicalizer::nameInstruction(Instruction *I) {
 ///
 /// \see getOutputFootprint()
 /// \param I Instruction to be renamed.
-void IRCanonicalizer::nameAsInitialInstruction(Instruction *I) {
+void IRNormalizer::nameAsInitialInstruction(Instruction *I) {
   if (I->getType()->isVoidTy() || (!I->getName().empty() && !RenameAll))
     return;
 
@@ -279,7 +279,7 @@ void IRCanonicalizer::nameAsInitialInstruction(Instruction *I) {
 ///
 /// \see getOutputFootprint()
 /// \param I Instruction to be renamed.
-void IRCanonicalizer::nameAsRegularInstruction(Instruction *I) {
+void IRNormalizer::nameAsRegularInstruction(Instruction *I) {
   // Instruction operands for further sorting.
   SmallVector<SmallString<128>, 4> Operands;
 
@@ -362,7 +362,7 @@ void IRCanonicalizer::nameAsRegularInstruction(Instruction *I) {
 /// does not affect user named instructions.
 ///
 /// \param I Instruction whose name will be folded.
-void IRCanonicalizer::foldInstructionName(Instruction *I) {
+void IRNormalizer::foldInstructionName(Instruction *I) {
   // If this flag is raised, fold all regular
   // instructions (including pre-outputs).
   if (!FoldPreoutputs) {
@@ -416,7 +416,7 @@ void IRCanonicalizer::foldInstructionName(Instruction *I) {
 ///
 /// \see reorderInstruction()
 /// \param Outputs Vector of pointers to output instructions collected top-down.
-void IRCanonicalizer::reorderInstructions(
+void IRNormalizer::reorderInstructions(
     SmallVector<Instruction *, 16> &Outputs) {
   // This method assumes output instructions were collected top-down,
   // otherwise the def-use chain may be broken.
@@ -438,7 +438,7 @@ void IRCanonicalizer::reorderInstructions(
 /// \param Used Pointer to the instruction whose value is used by the \p User.
 /// \param User Pointer to the instruction which uses the \p Used.
 /// \param Visited Set of visited instructions.
-void IRCanonicalizer::reorderInstruction(
+void IRNormalizer::reorderInstruction(
     Instruction *Used, Instruction *User,
     SmallPtrSet<const Instruction *, 32> &Visited) {
   if (isa<PHINode>(Used))
@@ -468,7 +468,7 @@ void IRCanonicalizer::reorderInstruction(
 /// in other instructions may change the semantics.
 ///
 /// \param I Instruction whose operands will be reordered.
-void IRCanonicalizer::reorderInstructionOperandsByNames(Instruction *I) {
+void IRNormalizer::reorderInstructionOperandsByNames(Instruction *I) {
   // This method assumes that passed I is commutative,
   // changing the order of operands in other instructions
   // may change the semantics.
@@ -507,7 +507,7 @@ void IRCanonicalizer::reorderInstructionOperandsByNames(Instruction *I) {
 /// blocks.
 ///
 /// \param PN PHI node to canonicalize.
-void IRCanonicalizer::reorderPHIIncomingValues(PHINode *PN) {
+void IRNormalizer::reorderPHIIncomingValues(PHINode *PN) {
   // Values for further sorting.
   SmallVector<std::pair<Value *, BasicBlock *>, 2> Values;
 
@@ -536,7 +536,7 @@ void IRCanonicalizer::reorderPHIIncomingValues(PHINode *PN) {
 /// \see isOutput()
 /// \param F Function to collect outputs from.
 SmallVector<Instruction *, 16>
-IRCanonicalizer::collectOutputInstructions(Function &F) {
+IRNormalizer::collectOutputInstructions(Function &F) {
   // Output instructions are collected top-down in each function,
   // any change may break the def-use chain in reordering methods.
   SmallVector<Instruction *, 16> Outputs;
@@ -552,7 +552,7 @@ IRCanonicalizer::collectOutputInstructions(Function &F) {
 /// ReturnInst.
 ///
 /// \param I Considered instruction.
-bool IRCanonicalizer::isOutput(const Instruction *I) {
+bool IRNormalizer::isOutput(const Instruction *I) {
   // Outputs are such instructions which may have side effects or is ReturnInst.
   if (I->mayHaveSideEffects() || isa<ReturnInst>(I))
     return true;
@@ -564,7 +564,7 @@ bool IRCanonicalizer::isOutput(const Instruction *I) {
 /// immediate operands.
 ///
 /// \param I Considered instruction.
-bool IRCanonicalizer::isInitialInstruction(const Instruction *I) {
+bool IRNormalizer::isInitialInstruction(const Instruction *I) {
   // Initial instructions are such instructions whose values are used by
   // other instructions, yet they only depend on immediate values.
   return !I->user_empty() && hasOnlyImmediateOperands(I);
@@ -573,7 +573,7 @@ bool IRCanonicalizer::isInitialInstruction(const Instruction *I) {
 /// Helper method checking whether the instruction has only immediate operands.
 ///
 /// \param I Considered instruction.
-bool IRCanonicalizer::hasOnlyImmediateOperands(const Instruction *I) {
+bool IRNormalizer::hasOnlyImmediateOperands(const Instruction *I) {
   for (const auto &OP : I->operands())
     if (isa<Instruction>(OP))
       return false; // Found non-immediate operand (instruction).
@@ -587,7 +587,7 @@ bool IRCanonicalizer::hasOnlyImmediateOperands(const Instruction *I) {
 ///
 /// \param I Considered instruction.
 /// \param Visited Set of visited instructions.
-SetVector<int> IRCanonicalizer::getOutputFootprint(
+SetVector<int> IRNormalizer::getOutputFootprint(
     Instruction *I, SmallPtrSet<const Instruction *, 32> &Visited) {
 
   // Vector containing indexes of outputs (no repetitions),
@@ -630,9 +630,9 @@ SetVector<int> IRCanonicalizer::getOutputFootprint(
   return Outputs;
 }
 
-PreservedAnalyses IRCanonicalizerPass::run(Function &F,
+PreservedAnalyses IRNormalizerPass::run(Function &F,
                                            FunctionAnalysisManager &AM) {
   errs() << F.getName() << "\n";
-  IRCanonicalizer{}.runOnFunction(F);
+  IRNormalizer{}.runOnFunction(F);
   return PreservedAnalyses::all();
 }
diff --git a/llvm/test/Transforms/IRCanonicalizer/infinite-loop.ll b/llvm/test/Transforms/IRNormalizer/infinite-loop.ll
similarity index 96%
rename from llvm/test/Transforms/IRCanonicalizer/infinite-loop.ll
rename to llvm/test/Transforms/IRNormalizer/infinite-loop.ll
index 3438a05b4aee48..9b10e91e49b4de 100644
--- a/llvm/test/Transforms/IRCanonicalizer/infinite-loop.ll
+++ b/llvm/test/Transforms/IRNormalizer/infinite-loop.ll
@@ -1,5 +1,5 @@
-; RUN: opt -passes=canon -preserve-order=true < %s
-; RUN: opt -passes=canon -preserve-order=false < %s
+; RUN: opt -passes=normalize -preserve-order=true < %s
+; RUN: opt -passes=normalize -preserve-order=false < %s
 
 define void @test(ptr, i32) {
 bb:
diff --git a/llvm/test/Transforms/IRCanonicalizer/naming-args-instr-blocks.ll b/llvm/test/Transforms/IRNormalizer/naming-args-instr-blocks.ll
similarity index 75%
rename from llvm/test/Transforms/IRCanonicalizer/naming-args-instr-blocks.ll
rename to llvm/test/Transforms/IRNormalizer/naming-args-instr-blocks.ll
index 605c62863f2ad3..afb99585db2ccf 100644
--- a/llvm/test/Transforms/IRCanonicalizer/naming-args-instr-blocks.ll
+++ b/llvm/test/Transforms/IRNormalizer/naming-args-instr-blocks.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=canon --rename-all --preserve-order < %s | FileCheck %s
+; RUN: opt -S -passes=normalize --rename-all --preserve-order < %s | FileCheck %s
 
 
 ; CHECK: @foo(i32 %a0)
diff --git a/llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll b/llvm/test/Transforms/IRNormalizer/naming-arguments.ll
similarity index 66%
rename from llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll
rename to llvm/test/Transforms/IRNormalizer/naming-arguments.ll
index b3f7630abd042f..3a1d435f76fdd0 100644
--- a/llvm/test/Transforms/IRCanonicalizer/naming-arguments.ll
+++ b/llvm/test/Transforms/IRNormalizer/naming-arguments.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=canon < %s | FileCheck %s
+; RUN: opt -S -passes=normalize < %s | FileCheck %s
 
 ; CHECK: @foo(i32 %a0, i32 %a1)
 define i32 @foo(i32, i32) {
diff --git a/llvm/test/Transforms/IRCanonicalizer/naming-basic-blocks.ll b/llvm/test/Transforms/IRNormalizer/naming-basic-blocks.ll
similarity index 60%
rename from llvm/test/Transforms/IRCanonicalizer/naming-basic-blocks.ll
rename to llvm/test/Transforms/IRNormalizer/naming-basic-blocks.ll
index 79e526f8efb7ac..f50c56bcca53f3 100644
--- a/llvm/test/Transforms/IRCanonicalizer/naming-basic-blocks.ll
+++ b/llvm/test/Transforms/IRNormalizer/naming-basic-blocks.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=canon --rename-all < %s | FileCheck %s
+; RUN: opt -S -passes=normalize --rename-all < %s | FileCheck %s
 
 define i32 @foo(i32 %a0) {
 ; CHECK: bb{{([0-9]{5})}}
diff --git a/llvm/test/Transforms/IRCanonicalizer/naming-instructions.ll b/llvm/test/Transforms/IRNormalizer/naming-instructions.ll
similarity index 80%
rename from llvm/test/Transforms/IRCanonicalizer/naming-instructions.ll
rename to llvm/test/Transforms/IRNormalizer/naming-instructions.ll
index a22e816f5bf01e..f1fe503f53ca1d 100644
--- a/llvm/test/Transforms/IRCanonicalizer/naming-instructions.ll
+++ b/llvm/test/Transforms/IRNormalizer/naming-instructions.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=canon --rename-all < %s | FileCheck %s
+; RUN: opt -S -passes=normalize --rename-all < %s | FileCheck %s
 
 define i32 @foo(i32 %a0) {
 entry:
diff --git a/llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll b/llvm/test/Transforms/IRNormalizer/reordering-instructions.ll
similarity index 83%
rename from llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll
rename to llvm/test/Transforms/IRNormalizer/reordering-instructions.ll
index 04660ac73c11bd..8978b01c3caa6d 100644
--- a/llvm/test/Transforms/IRCanonicalizer/reordering-instructions.ll
+++ b/llvm/test/Transforms/IRNormalizer/reordering-instructions.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=canon < %s | FileCheck %s
+; RUN: opt -S -passes=normalize < %s | FileCheck %s
 
 define double @foo(double %a0, double %a1) {
 entry:
diff --git a/llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll b/llvm/test/Transforms/IRNormalizer/reordering-phi-node-values.ll
similarity index 91%
rename from llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll
rename to llvm/test/Transforms/IRNormalizer/reordering-phi-node-values.ll
index 5f344ec29be66f..cba92e8eaf9ac5 100644
--- a/llvm/test/Transforms/IRCanonicalizer/reordering-phi-node-values.ll
+++ b/llvm/test/Transforms/IRNormalizer/reordering-phi-node-values.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=canon < %s | FileCheck %s
+; RUN: opt -S -passes=normalize < %s | FileCheck %s
 
 declare double @foo()
 

>From 50fe4fd4c20aa078d435b9dfed1af2201d2c8646 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 14 Oct 2023 18:07:59 -0400
Subject: [PATCH 18/50] Removing debugging line

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index da2cbc41346d01..a3bf5d1b940913 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -632,7 +632,6 @@ SetVector<int> IRNormalizer::getOutputFootprint(
 
 PreservedAnalyses IRNormalizerPass::run(Function &F,
                                            FunctionAnalysisManager &AM) {
-  errs() << F.getName() << "\n";
   IRNormalizer{}.runOnFunction(F);
   return PreservedAnalyses::all();
 }

>From 4f843fbacec015a7e6fdbdf8aa32dd96b0e91253 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sun, 15 Oct 2023 23:13:32 -0400
Subject: [PATCH 19/50] clang-format changes

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index a3bf5d1b940913..dd6ad517ddd763 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -631,7 +631,7 @@ SetVector<int> IRNormalizer::getOutputFootprint(
 }
 
 PreservedAnalyses IRNormalizerPass::run(Function &F,
-                                           FunctionAnalysisManager &AM) {
+                                        FunctionAnalysisManager &AM) {
   IRNormalizer{}.runOnFunction(F);
   return PreservedAnalyses::all();
 }

>From 45e9eeaa81dea2323353cef3931ea293b4c52ba6 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 21 Oct 2023 14:04:05 -0700
Subject: [PATCH 20/50] Incorporate fixes

---
 llvm/docs/Passes.rst                       | 12 ++++++------
 llvm/docs/ReleaseNotes.rst                 |  2 +-
 llvm/lib/Transforms/Utils/IRNormalizer.cpp |  6 +++---
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/llvm/docs/Passes.rst b/llvm/docs/Passes.rst
index 250002a65fecaf..22432b3ce60325 100644
--- a/llvm/docs/Passes.rst
+++ b/llvm/docs/Passes.rst
@@ -544,15 +544,15 @@ An interprocedural variant of :ref:`Sparse Conditional Constant Propagation
 <passes-sccp>`.
 
 ``ir-normalizer``: Transforms IR into a canonical form that's easier to diff
---------------------------------------------------------
+----------------------------------------------------------------------------
 
 This pass aims to transform LLVM Modules into a canonical form by reordering and
-renaming instructions while preserving the same semantics. The canonicalizer makes
-it easier to spot semantic differences while diffing two modules which have undergone
-two different passes.
+renaming instructions while preserving the same semantics. The normalizer makes
+it easier to spot semantic differences while diffing two modules which have
+undergone two different passes.
 
-``-jump-threading``: Jump Threading
------------------------------------
+``jump-threading``: Jump Threading
+----------------------------------
 
 Jump threading tries to find distinct threads of control flow running through a
 basic block.  This pass looks at blocks that have multiple predecessors and
diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index 6786abaee73645..a12cf481444018 100644
--- a/llvm/docs/ReleaseNotes.rst
+++ b/llvm/docs/ReleaseNotes.rst
@@ -44,7 +44,7 @@ Non-comprehensive list of changes in this release
 
 * Added a new IRNormalizer pass which aims to transform LLVM modules into
   a canonical form by reordering and renaming instructions while preserving the
-  same semantics. The canonicalizer makes it easier to spot semantic differences
+  same semantics. The normalizer makes it easier to spot semantic differences
   when diffing two modules which have undergone different passes.
 
 Update on required toolchains to build LLVM
diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index dd6ad517ddd763..539a5388799717 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -1,4 +1,4 @@
-//===--------------- IRNormalizer.cpp - IR Canonicalizer ---------------===//
+//===--------------- IRNormalizer.cpp - IR Normalizer ---------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -40,7 +40,7 @@ namespace {
 /// IRNormalizer aims to transform LLVM IR into canonical form.
 class IRNormalizer {
 public:
-  /// \name Canonicalizer flags.
+  /// \name Normalizer flags.
   /// @{
   /// Preserves original order of instructions.
   static cl::opt<bool> PreserveOrder;
@@ -106,7 +106,7 @@ cl::opt<bool> IRNormalizer::ReorderOperands(
 
 /// Entry method to the IRNormalizer.
 ///
-/// \param M Module to canonicalize.
+/// \param M Module to normalize.
 bool IRNormalizer::runOnFunction(Function &F) {
   nameFunctionArguments(F);
   nameBasicBlocks(F);

>From 22b79c72649d1594c8040f54b0b2713909da3d5b Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Fri, 10 Nov 2023 12:16:44 -0800
Subject: [PATCH 21/50] Add LLVM_DEBUG() for reordering code

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 539a5388799717..378db63e0bb77e 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -424,10 +424,12 @@ void IRNormalizer::reorderInstructions(
   SmallPtrSet<const Instruction *, 32> Visited;
 
   // Walk up the tree.
-  for (auto &I : Outputs)
+  for (auto &I : Outputs) {
+    LLVM_DEBUG(dbgs() << "Reordering operands of: "; I->dump());
     for (auto &OP : I->operands())
       if (auto *IOP = dyn_cast<Instruction>(OP))
         reorderInstruction(IOP, I, Visited);
+  }
 }
 
 /// Reduces def-use distance or places instruction at the end of the basic
@@ -449,9 +451,12 @@ void IRNormalizer::reorderInstruction(
 
   if (Used->getParent() == User->getParent()) {
     // If Used and User share the same basic block move Used just before User.
+    LLVM_DEBUG(dbgs() << "\tMoved " << *Used << " before " << *User << "\n");
     Used->moveBefore(User);
   } else {
     // Otherwise move Used to the very end of its basic block.
+    LLVM_DEBUG(dbgs() << "\tMoved " << *Used << " to end of block " << 
+               Used->getParent()->getName() << "\n");
     Used->moveBefore(&Used->getParent()->back());
   }
 

>From a5303ef2222ffc046189870a0dc9adb924128106 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Fri, 10 Nov 2023 12:17:32 -0800
Subject: [PATCH 22/50] Accepts F not M

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 378db63e0bb77e..01f6c923dbfcfc 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -106,7 +106,7 @@ cl::opt<bool> IRNormalizer::ReorderOperands(
 
 /// Entry method to the IRNormalizer.
 ///
-/// \param M Module to normalize.
+/// \param F Function to normalize.
 bool IRNormalizer::runOnFunction(Function &F) {
   nameFunctionArguments(F);
   nameBasicBlocks(F);

>From d8213b692e25828cf39bd81f50399960ff26af8d Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Fri, 10 Nov 2023 12:20:11 -0800
Subject: [PATCH 23/50] Fix nits

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 01f6c923dbfcfc..6b615ad729e751 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -180,9 +180,7 @@ void IRNormalizer::nameInstruction(Instruction *I) {
   if (NamedInstructions.contains(I))
     return;
   NamedInstructions.insert(I);
-  // Determine the type of instruction to name.
   if (isInitialInstruction(I)) {
-    // This is an initial instruction.
     nameAsInitialInstruction(I);
   } else {
     // This must be a regular instruction.
@@ -245,9 +243,8 @@ void IRNormalizer::nameAsInitialInstruction(Instruction *I) {
   if (const auto *CI = dyn_cast<CallInst>(I)) {
     Function *F = CI->getCalledFunction();
 
-    if (F != nullptr) {
+    if (F != nullptr)
       Name.append(F->getName());
-    }
   }
 
   Name.append("(");
@@ -294,7 +291,7 @@ void IRNormalizer::nameAsRegularInstruction(Instruction *I) {
       // Walk down the use-def chain.
       nameInstruction(IOP);
       Operands.push_back(IOP->getName());
-    } else if (isa<Value>(OP) && !isa<Function>(OP)) {
+    } else if (!isa<Function>(OP)) {
       // This must be an immediate value.
       std::string TextRepresentation;
       raw_string_ostream Stream(TextRepresentation);

>From 3fc8a170ad50775249a2a43eb996dde28d6bfc48 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Fri, 10 Nov 2023 12:28:46 -0800
Subject: [PATCH 24/50] Spelling fix

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 6b615ad729e751..956f0ff8799f3f 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -47,7 +47,7 @@ class IRNormalizer {
   /// Renames all instructions (including user-named).
   static cl::opt<bool> RenameAll;
   /// Folds all regular instructions (including pre-outputs).
-  static cl::opt<bool> FoldPreoutputs;
+  static cl::opt<bool> FoldPreOutputs;
   /// Sorts and reorders operands in commutative instructions.
   static cl::opt<bool> ReorderOperands;
   /// @}
@@ -97,7 +97,7 @@ cl::opt<bool> IRNormalizer::PreserveOrder(
 cl::opt<bool> IRNormalizer::RenameAll(
     "rename-all", cl::Hidden,
     cl::desc("Renames all instructions (including user-named)"));
-cl::opt<bool> IRNormalizer::FoldPreoutputs(
+cl::opt<bool> IRNormalizer::FoldPreOutputs(
     "fold-all", cl::Hidden,
     cl::desc("Folds all regular instructions (including pre-outputs)"));
 cl::opt<bool> IRNormalizer::ReorderOperands(
@@ -362,7 +362,7 @@ void IRNormalizer::nameAsRegularInstruction(Instruction *I) {
 void IRNormalizer::foldInstructionName(Instruction *I) {
   // If this flag is raised, fold all regular
   // instructions (including pre-outputs).
-  if (!FoldPreoutputs) {
+  if (!FoldPreOutputs) {
     // Don't fold if one of the users is an output instruction.
     for (auto *U : I->users())
       if (auto *IU = dyn_cast<Instruction>(U))

>From 410126053c2c797287cefa860592f81a4f78d9ba Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Fri, 10 Nov 2023 15:06:01 -0800
Subject: [PATCH 25/50] Only sort the first two commutative operands

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 32 ++++++++++++++++++----
 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 956f0ff8799f3f..66013dcc206cd5 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -80,6 +80,10 @@ class IRNormalizer {
 
   /// \name Utility methods.
   /// @{
+  template<typename T>
+  void sortCommutativeOperands(T &Operands) const; 
+  template<typename T, typename Compare>
+  void sortCommutativeOperands(T &Operands, Compare Comp) const; 
   SmallVector<Instruction *, 16> collectOutputInstructions(Function &F);
   bool isOutput(const Instruction *I);
   bool isInitialInstruction(const Instruction *I);
@@ -188,6 +192,24 @@ void IRNormalizer::nameInstruction(Instruction *I) {
   }
 }
 
+template<typename T>
+void IRNormalizer::sortCommutativeOperands(T &Operands) const {
+  if (Operands.size() < 2)
+    return;
+  auto CommutativeEnd = Operands.begin();
+  std::advance(CommutativeEnd, 2);
+  llvm::sort(Operands.begin(), CommutativeEnd);
+}
+
+template<typename T, typename Compare>
+void IRNormalizer::sortCommutativeOperands(T &Operands, Compare Comp) const {
+  if (Operands.size() < 2)
+    return;
+  auto CommutativeEnd = Operands.begin();
+  std::advance(CommutativeEnd, 2);
+  llvm::sort(Operands.begin(), CommutativeEnd, Comp);
+}
+
 /// Names instruction following the scheme:
 /// vl00000Callee(Operands)
 ///
@@ -219,7 +241,7 @@ void IRNormalizer::nameAsInitialInstruction(Instruction *I) {
   }
 
   if (I->isCommutative())
-    llvm::sort(Operands);
+    sortCommutativeOperands(Operands);
 
   // Initialize to a magic constant, so the state isn't zero.
   uint64_t Hash = MagicHashConstant;
@@ -301,7 +323,7 @@ void IRNormalizer::nameAsRegularInstruction(Instruction *I) {
   }
 
   if (I->isCommutative())
-    llvm::sort(Operands.begin(), Operands.end());
+    sortCommutativeOperands(Operands);
 
   // Initialize to a magic constant, so the state isn't zero.
   uint64_t Hash = MagicHashConstant;
@@ -318,7 +340,7 @@ void IRNormalizer::nameAsRegularInstruction(Instruction *I) {
       OperandsOpcodes.push_back(IOP->getOpcode());
 
   if (I->isCommutative())
-    llvm::sort(OperandsOpcodes.begin(), OperandsOpcodes.end());
+    sortCommutativeOperands(OperandsOpcodes);
 
   // Consider operand opcodes in the hash.
   for (const int Code : OperandsOpcodes)
@@ -388,7 +410,7 @@ void IRNormalizer::foldInstructionName(Instruction *I) {
   }
 
   if (I->isCommutative())
-    llvm::sort(Operands.begin(), Operands.end());
+    sortCommutativeOperands(Operands);
 
   SmallString<256> Name;
   Name.append(I->getName().substr(0, 7));
@@ -495,7 +517,7 @@ void IRNormalizer::reorderInstructionOperandsByNames(Instruction *I) {
   }
 
   // Sort operands.
-  llvm::sort(Operands.begin(), Operands.end(), llvm::less_first());
+  sortCommutativeOperands(Operands, llvm::less_first());
 
   // Reorder operands.
   unsigned Position = 0;

>From 9f79701b877868a010c10472c9c67e9a5f1cc2d8 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Fri, 10 Nov 2023 15:19:11 -0800
Subject: [PATCH 26/50] Add LLVM_DEBUG for instruction renaming

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 66013dcc206cd5..7e609199482036 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -226,6 +226,7 @@ void IRNormalizer::sortCommutativeOperands(T &Operands, Compare Comp) const {
 void IRNormalizer::nameAsInitialInstruction(Instruction *I) {
   if (I->getType()->isVoidTy() || (!I->getName().empty() && !RenameAll))
     return;
+  LLVM_DEBUG(dbgs() << "Naming initial instruction: " << *I << "\n");
 
   // Instruction operands for further sorting.
   SmallVector<SmallString<64>, 4> Operands;
@@ -299,6 +300,8 @@ void IRNormalizer::nameAsInitialInstruction(Instruction *I) {
 /// \see getOutputFootprint()
 /// \param I Instruction to be renamed.
 void IRNormalizer::nameAsRegularInstruction(Instruction *I) {
+  LLVM_DEBUG(dbgs() << "Naming regular instruction: " << *I << "\n");
+  
   // Instruction operands for further sorting.
   SmallVector<SmallString<128>, 4> Operands;
 

>From 64e12edd21446f319c835d34d0a98e9dc01276c0 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Fri, 10 Nov 2023 17:16:30 -0800
Subject: [PATCH 27/50] Canonical -> Normal

---
 llvm/docs/Passes.rst                              |  4 ++--
 llvm/docs/ReleaseNotes.rst                        |  2 +-
 llvm/include/llvm/Transforms/Utils/IRNormalizer.h |  2 +-
 llvm/lib/Transforms/Utils/IRNormalizer.cpp        | 12 ++++++------
 4 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/llvm/docs/Passes.rst b/llvm/docs/Passes.rst
index 22432b3ce60325..883829f4d2b5bd 100644
--- a/llvm/docs/Passes.rst
+++ b/llvm/docs/Passes.rst
@@ -543,10 +543,10 @@ variables with initializers are marked as internal.
 An interprocedural variant of :ref:`Sparse Conditional Constant Propagation
 <passes-sccp>`.
 
-``ir-normalizer``: Transforms IR into a canonical form that's easier to diff
+``ir-normalizer``: Transforms IR into a normal form that's easier to diff
 ----------------------------------------------------------------------------
 
-This pass aims to transform LLVM Modules into a canonical form by reordering and
+This pass aims to transform LLVM Modules into a normal form by reordering and
 renaming instructions while preserving the same semantics. The normalizer makes
 it easier to spot semantic differences while diffing two modules which have
 undergone two different passes.
diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index a12cf481444018..f5f3fedd02e099 100644
--- a/llvm/docs/ReleaseNotes.rst
+++ b/llvm/docs/ReleaseNotes.rst
@@ -43,7 +43,7 @@ Non-comprehensive list of changes in this release
    for adding a new subsection.
 
 * Added a new IRNormalizer pass which aims to transform LLVM modules into
-  a canonical form by reordering and renaming instructions while preserving the
+  a normal form by reordering and renaming instructions while preserving the
   same semantics. The normalizer makes it easier to spot semantic differences
   when diffing two modules which have undergone different passes.
 
diff --git a/llvm/include/llvm/Transforms/Utils/IRNormalizer.h b/llvm/include/llvm/Transforms/Utils/IRNormalizer.h
index 2e3e23340bc5bc..b5df02e6ac87cc 100644
--- a/llvm/include/llvm/Transforms/Utils/IRNormalizer.h
+++ b/llvm/include/llvm/Transforms/Utils/IRNormalizer.h
@@ -5,7 +5,7 @@
 
 namespace llvm {
 
-/// IRNormalizer aims to transform LLVM IR into canonical form.
+/// IRNormalizer aims to transform LLVM IR into normal form.
 struct IRNormalizerPass : public PassInfoMixin<IRNormalizerPass> {
   PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
 };
diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 7e609199482036..42dad3d4eceb56 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -7,7 +7,7 @@
 //===----------------------------------------------------------------------===//
 /// \file
 /// This file implements the IRNormalizer class which aims to transform LLVM
-/// Modules into a canonical form by reordering and renaming instructions while
+/// Modules into a normal form by reordering and renaming instructions while
 /// preserving the same semantics. The normalizer makes it easier to spot
 /// semantic differences while diffing two modules which have undergone
 /// different passes.
@@ -37,7 +37,7 @@
 using namespace llvm;
 
 namespace {
-/// IRNormalizer aims to transform LLVM IR into canonical form.
+/// IRNormalizer aims to transform LLVM IR into normal form.
 class IRNormalizer {
 public:
   /// \name Normalizer flags.
@@ -301,7 +301,7 @@ void IRNormalizer::nameAsInitialInstruction(Instruction *I) {
 /// \param I Instruction to be renamed.
 void IRNormalizer::nameAsRegularInstruction(Instruction *I) {
   LLVM_DEBUG(dbgs() << "Naming regular instruction: " << *I << "\n");
-  
+
   // Instruction operands for further sorting.
   SmallVector<SmallString<128>, 4> Operands;
 
@@ -404,10 +404,10 @@ void IRNormalizer::foldInstructionName(Instruction *I) {
 
   for (auto &OP : I->operands()) {
     if (const auto *IOP = dyn_cast<Instruction>(OP)) {
-      bool HasCanonicalName = I->getName().substr(0, 2) == "op" ||
+      bool HasNormalName = I->getName().substr(0, 2) == "op" ||
                               I->getName().substr(0, 2) == "vl";
 
-      Operands.push_back(HasCanonicalName ? IOP->getName().substr(0, 7)
+      Operands.push_back(HasNormalName ? IOP->getName().substr(0, 7)
                                           : IOP->getName());
     }
   }
@@ -533,7 +533,7 @@ void IRNormalizer::reorderInstructionOperandsByNames(Instruction *I) {
 /// Reorders PHI node's values according to the names of corresponding basic
 /// blocks.
 ///
-/// \param PN PHI node to canonicalize.
+/// \param PN PHI node to normalize.
 void IRNormalizer::reorderPHIIncomingValues(PHINode *PN) {
   // Values for further sorting.
   SmallVector<std::pair<Value *, BasicBlock *>, 2> Values;

>From 563bb82fc48a6c4678da78a5e51dea574a228fc8 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Fri, 10 Nov 2023 17:18:33 -0800
Subject: [PATCH 28/50] clang-format changes

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 42dad3d4eceb56..a93f1e2c30b7b5 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -80,9 +80,8 @@ class IRNormalizer {
 
   /// \name Utility methods.
   /// @{
-  template<typename T>
-  void sortCommutativeOperands(T &Operands) const; 
-  template<typename T, typename Compare>
+  template <typename T> void sortCommutativeOperands(T &Operands) const; 
+  template <typename T, typename Compare>
   void sortCommutativeOperands(T &Operands, Compare Comp) const; 
   SmallVector<Instruction *, 16> collectOutputInstructions(Function &F);
   bool isOutput(const Instruction *I);
@@ -192,7 +191,7 @@ void IRNormalizer::nameInstruction(Instruction *I) {
   }
 }
 
-template<typename T>
+template <typename T>
 void IRNormalizer::sortCommutativeOperands(T &Operands) const {
   if (Operands.size() < 2)
     return;
@@ -201,7 +200,7 @@ void IRNormalizer::sortCommutativeOperands(T &Operands) const {
   llvm::sort(Operands.begin(), CommutativeEnd);
 }
 
-template<typename T, typename Compare>
+template <typename T, typename Compare>
 void IRNormalizer::sortCommutativeOperands(T &Operands, Compare Comp) const {
   if (Operands.size() < 2)
     return;
@@ -477,8 +476,8 @@ void IRNormalizer::reorderInstruction(
     Used->moveBefore(User);
   } else {
     // Otherwise move Used to the very end of its basic block.
-    LLVM_DEBUG(dbgs() << "\tMoved " << *Used << " to end of block " << 
-               Used->getParent()->getName() << "\n");
+    LLVM_DEBUG(dbgs() << "\tMoved " << *Used << " to end of block " 
+                      << Used->getParent()->getName() << "\n");
     Used->moveBefore(&Used->getParent()->back());
   }
 

>From c5c1a3ec91c9e31169fbe180b8df2ae919eccc2a Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Fri, 10 Nov 2023 19:16:35 -0800
Subject: [PATCH 29/50] Prefix cli arguments with "norm"

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp                | 8 ++++----
 llvm/test/Transforms/IRNormalizer/infinite-loop.ll        | 4 ++--
 .../Transforms/IRNormalizer/naming-args-instr-blocks.ll   | 3 +--
 llvm/test/Transforms/IRNormalizer/naming-basic-blocks.ll  | 2 +-
 llvm/test/Transforms/IRNormalizer/naming-instructions.ll  | 2 +-
 5 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index a93f1e2c30b7b5..8d6ea64405495c 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -95,16 +95,16 @@ class IRNormalizer {
 } // namespace
 
 cl::opt<bool> IRNormalizer::PreserveOrder(
-    "preserve-order", cl::Hidden,
+    "norm-preserve-order", cl::Hidden,
     cl::desc("Preserves original instruction order"));
 cl::opt<bool> IRNormalizer::RenameAll(
-    "rename-all", cl::Hidden,
+    "norm-rename-all", cl::Hidden,
     cl::desc("Renames all instructions (including user-named)"));
 cl::opt<bool> IRNormalizer::FoldPreOutputs(
-    "fold-all", cl::Hidden,
+    "norm-fold-all", cl::Hidden,
     cl::desc("Folds all regular instructions (including pre-outputs)"));
 cl::opt<bool> IRNormalizer::ReorderOperands(
-    "reorder-operands", cl::Hidden,
+    "norm-reorder-operands", cl::Hidden,
     cl::desc("Sorts and reorders operands in commutative instructions"));
 
 /// Entry method to the IRNormalizer.
diff --git a/llvm/test/Transforms/IRNormalizer/infinite-loop.ll b/llvm/test/Transforms/IRNormalizer/infinite-loop.ll
index 9b10e91e49b4de..109858e97fd36a 100644
--- a/llvm/test/Transforms/IRNormalizer/infinite-loop.ll
+++ b/llvm/test/Transforms/IRNormalizer/infinite-loop.ll
@@ -1,5 +1,5 @@
-; RUN: opt -passes=normalize -preserve-order=true < %s
-; RUN: opt -passes=normalize -preserve-order=false < %s
+; RUN: opt -passes=normalize -norm-preserve-order=true < %s
+; RUN: opt -passes=normalize -norm-preserve-order=false < %s
 
 define void @test(ptr, i32) {
 bb:
diff --git a/llvm/test/Transforms/IRNormalizer/naming-args-instr-blocks.ll b/llvm/test/Transforms/IRNormalizer/naming-args-instr-blocks.ll
index afb99585db2ccf..104ffc8dd6e39f 100644
--- a/llvm/test/Transforms/IRNormalizer/naming-args-instr-blocks.ll
+++ b/llvm/test/Transforms/IRNormalizer/naming-args-instr-blocks.ll
@@ -1,5 +1,4 @@
-; RUN: opt -S -passes=normalize --rename-all --preserve-order < %s | FileCheck %s
-
+; RUN: opt -S -passes=normalize -norm-rename-all -norm-preserve-order < %s | FileCheck %s
 
 ; CHECK: @foo(i32 %a0)
 define i32 @foo(i32) {
diff --git a/llvm/test/Transforms/IRNormalizer/naming-basic-blocks.ll b/llvm/test/Transforms/IRNormalizer/naming-basic-blocks.ll
index f50c56bcca53f3..9493b3f70ef763 100644
--- a/llvm/test/Transforms/IRNormalizer/naming-basic-blocks.ll
+++ b/llvm/test/Transforms/IRNormalizer/naming-basic-blocks.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=normalize --rename-all < %s | FileCheck %s
+; RUN: opt -S -passes=normalize -norm-rename-all < %s | FileCheck %s
 
 define i32 @foo(i32 %a0) {
 ; CHECK: bb{{([0-9]{5})}}
diff --git a/llvm/test/Transforms/IRNormalizer/naming-instructions.ll b/llvm/test/Transforms/IRNormalizer/naming-instructions.ll
index f1fe503f53ca1d..c08ef18f948c83 100644
--- a/llvm/test/Transforms/IRNormalizer/naming-instructions.ll
+++ b/llvm/test/Transforms/IRNormalizer/naming-instructions.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -passes=normalize --rename-all < %s | FileCheck %s
+; RUN: opt -S -passes=normalize -norm-rename-all < %s | FileCheck %s
 
 define i32 @foo(i32 %a0) {
 entry:

>From edfbdf32d0951ca6c27e74e3606c5725da76912d Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Fri, 10 Nov 2023 19:18:16 -0800
Subject: [PATCH 30/50] clang-format changes

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 8d6ea64405495c..7fed01e540d94c 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -80,9 +80,9 @@ class IRNormalizer {
 
   /// \name Utility methods.
   /// @{
-  template <typename T> void sortCommutativeOperands(T &Operands) const; 
+  template <typename T> void sortCommutativeOperands(T &Operands) const;
   template <typename T, typename Compare>
-  void sortCommutativeOperands(T &Operands, Compare Comp) const; 
+  void sortCommutativeOperands(T &Operands, Compare Comp) const;
   SmallVector<Instruction *, 16> collectOutputInstructions(Function &F);
   bool isOutput(const Instruction *I);
   bool isInitialInstruction(const Instruction *I);
@@ -407,7 +407,7 @@ void IRNormalizer::foldInstructionName(Instruction *I) {
                               I->getName().substr(0, 2) == "vl";
 
       Operands.push_back(HasNormalName ? IOP->getName().substr(0, 7)
-                                          : IOP->getName());
+                                       : IOP->getName());
     }
   }
 
@@ -476,7 +476,7 @@ void IRNormalizer::reorderInstruction(
     Used->moveBefore(User);
   } else {
     // Otherwise move Used to the very end of its basic block.
-    LLVM_DEBUG(dbgs() << "\tMoved " << *Used << " to end of block " 
+    LLVM_DEBUG(dbgs() << "\tMoved " << *Used << " to end of block "
                       << Used->getParent()->getName() << "\n");
     Used->moveBefore(&Used->getParent()->back());
   }

>From 416ef0a1c8f2cb040207308abcda890a662dc746 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 11 Nov 2023 13:37:20 -0800
Subject: [PATCH 31/50] clang-format changes

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 7fed01e540d94c..61193c4b794842 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -404,7 +404,7 @@ void IRNormalizer::foldInstructionName(Instruction *I) {
   for (auto &OP : I->operands()) {
     if (const auto *IOP = dyn_cast<Instruction>(OP)) {
       bool HasNormalName = I->getName().substr(0, 2) == "op" ||
-                              I->getName().substr(0, 2) == "vl";
+                           I->getName().substr(0, 2) == "vl";
 
       Operands.push_back(HasNormalName ? IOP->getName().substr(0, 7)
                                        : IOP->getName());

>From 77b8b886dc8cd6ede6fcbe9c6a4928a7c60da39c Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 11 Nov 2023 17:32:07 -0800
Subject: [PATCH 32/50] Use const + WIP

---
 .../llvm/Transforms/Utils/IRNormalizer.h      |  2 +-
 llvm/lib/Transforms/Utils/IRNormalizer.cpp    | 81 +++++++++----------
 2 files changed, 41 insertions(+), 42 deletions(-)

diff --git a/llvm/include/llvm/Transforms/Utils/IRNormalizer.h b/llvm/include/llvm/Transforms/Utils/IRNormalizer.h
index b5df02e6ac87cc..af1f715d4940d8 100644
--- a/llvm/include/llvm/Transforms/Utils/IRNormalizer.h
+++ b/llvm/include/llvm/Transforms/Utils/IRNormalizer.h
@@ -7,7 +7,7 @@ namespace llvm {
 
 /// IRNormalizer aims to transform LLVM IR into normal form.
 struct IRNormalizerPass : public PassInfoMixin<IRNormalizerPass> {
-  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM) const;
 };
 
 } // namespace llvm
diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 61193c4b794842..2ce155233df6bf 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -59,23 +59,26 @@ class IRNormalizer {
   const uint64_t MagicHashConstant = 0x6acaa36bef8325c5ULL;
   DenseSet<const Instruction *> NamedInstructions;
 
+  SmallVector<Instruction *, 16> Outputs;
+
   /// \name Naming.
   /// @{
-  void nameFunctionArguments(Function &F);
-  void nameBasicBlocks(Function &F);
+  void nameFunctionArguments(Function &F) const;
+  void nameBasicBlocks(Function &F) const;
   void nameInstruction(Instruction *I);
-  void nameAsInitialInstruction(Instruction *I);
+  void nameAsInitialInstruction(Instruction *I) const;
   void nameAsRegularInstruction(Instruction *I);
-  void foldInstructionName(Instruction *I);
+  void foldInstructionName(Instruction *I) const;
   /// @}
 
   /// \name Reordering.
   /// @{
-  void reorderInstructions(SmallVector<Instruction *, 16> &Outputs);
+  void reorderInstructions(Function &F) const;
+  void reorderInstructionsInBasicBlock(BasicBlock &BB) const;
   void reorderInstruction(Instruction *Used, Instruction *User,
-                          SmallPtrSet<const Instruction *, 32> &Visited);
-  void reorderInstructionOperandsByNames(Instruction *I);
-  void reorderPHIIncomingValues(PHINode *PN);
+                          SmallPtrSet<const Instruction *, 32> &Visited) const;
+  void reorderInstructionOperandsByNames(Instruction *I) const;
+  void reorderPHIIncomingValues(PHINode *PN) const;
   /// @}
 
   /// \name Utility methods.
@@ -83,13 +86,13 @@ class IRNormalizer {
   template <typename T> void sortCommutativeOperands(T &Operands) const;
   template <typename T, typename Compare>
   void sortCommutativeOperands(T &Operands, Compare Comp) const;
-  SmallVector<Instruction *, 16> collectOutputInstructions(Function &F);
-  bool isOutput(const Instruction *I);
-  bool isInitialInstruction(const Instruction *I);
-  bool hasOnlyImmediateOperands(const Instruction *I);
+  SmallVector<Instruction *, 16> collectOutputInstructions(Function &F) const;
+  bool isOutput(const Instruction *I) const;
+  bool isInitialInstruction(const Instruction *I) const;
+  bool hasOnlyImmediateOperands(const Instruction *I) const;
   SetVector<int>
   getOutputFootprint(Instruction *I,
-                     SmallPtrSet<const Instruction *, 32> &Visited);
+                     SmallPtrSet<const Instruction *, 32> &Visited) const;
   /// @}
 };
 } // namespace
@@ -114,10 +117,10 @@ bool IRNormalizer::runOnFunction(Function &F) {
   nameFunctionArguments(F);
   nameBasicBlocks(F);
 
-  SmallVector<Instruction *, 16> Outputs = collectOutputInstructions(F);
+  Outputs = collectOutputInstructions(F);
 
   if (!PreserveOrder)
-    reorderInstructions(Outputs);
+    reorderInstructions(F);
 
   for (auto &I : Outputs)
     nameInstruction(I);
@@ -140,7 +143,7 @@ bool IRNormalizer::runOnFunction(Function &F) {
 /// Numbers arguments.
 ///
 /// \param F Function whose arguments will be renamed.
-void IRNormalizer::nameFunctionArguments(Function &F) {
+void IRNormalizer::nameFunctionArguments(Function &F) const {
   int ArgumentCounter = 0;
   for (auto &A : F.args()) {
     if (RenameAll || A.getName().empty()) {
@@ -154,7 +157,7 @@ void IRNormalizer::nameFunctionArguments(Function &F) {
 /// a function considering the opcode and the order of output instructions.
 ///
 /// \param F Function containing basic blocks to rename.
-void IRNormalizer::nameBasicBlocks(Function &F) {
+void IRNormalizer::nameBasicBlocks(Function &F) const {
   for (auto &B : F) {
     // Initialize to a magic constant, so the state isn't zero.
     uint64_t Hash = MagicHashConstant;
@@ -222,7 +225,7 @@ void IRNormalizer::sortCommutativeOperands(T &Operands, Compare Comp) const {
 ///
 /// \see getOutputFootprint()
 /// \param I Instruction to be renamed.
-void IRNormalizer::nameAsInitialInstruction(Instruction *I) {
+void IRNormalizer::nameAsInitialInstruction(Instruction *I) const {
   if (I->getType()->isVoidTy() || (!I->getName().empty() && !RenameAll))
     return;
   LLVM_DEBUG(dbgs() << "Naming initial instruction: " << *I << "\n");
@@ -383,7 +386,7 @@ void IRNormalizer::nameAsRegularInstruction(Instruction *I) {
 /// does not affect user named instructions.
 ///
 /// \param I Instruction whose name will be folded.
-void IRNormalizer::foldInstructionName(Instruction *I) {
+void IRNormalizer::foldInstructionName(Instruction *I) const {
   // If this flag is raised, fold all regular
   // instructions (including pre-outputs).
   if (!FoldPreOutputs) {
@@ -436,21 +439,17 @@ void IRNormalizer::foldInstructionName(Instruction *I) {
 /// This method is a wrapper for recursive reorderInstruction().
 ///
 /// \see reorderInstruction()
-/// \param Outputs Vector of pointers to output instructions collected top-down.
-void IRNormalizer::reorderInstructions(
-    SmallVector<Instruction *, 16> &Outputs) {
-  // This method assumes output instructions were collected top-down,
-  // otherwise the def-use chain may be broken.
+void IRNormalizer::reorderInstructions(Function &F) const {
+  SmallPtrSet<const Instruction *, 32> UsedInFunction;
+  for (auto &BB : F) {
+    LLVM_DEBUG(dbgs() << "Reordering instructions of basic block: " 
+                      << BB.getName());
+    reorderInstructionsInBasicBlock(BB);
+  }
+}
 
-  SmallPtrSet<const Instruction *, 32> Visited;
+void IRNormalizer::reorderInstructionsInBasicBlock(BasicBlock &BB) const {
 
-  // Walk up the tree.
-  for (auto &I : Outputs) {
-    LLVM_DEBUG(dbgs() << "Reordering operands of: "; I->dump());
-    for (auto &OP : I->operands())
-      if (auto *IOP = dyn_cast<Instruction>(OP))
-        reorderInstruction(IOP, I, Visited);
-  }
 }
 
 /// Reduces def-use distance or places instruction at the end of the basic
@@ -463,7 +462,7 @@ void IRNormalizer::reorderInstructions(
 /// \param Visited Set of visited instructions.
 void IRNormalizer::reorderInstruction(
     Instruction *Used, Instruction *User,
-    SmallPtrSet<const Instruction *, 32> &Visited) {
+    SmallPtrSet<const Instruction *, 32> &Visited) const {
   if (isa<PHINode>(Used))
     return;
   if (Visited.contains(Used))
@@ -494,7 +493,7 @@ void IRNormalizer::reorderInstruction(
 /// in other instructions may change the semantics.
 ///
 /// \param I Instruction whose operands will be reordered.
-void IRNormalizer::reorderInstructionOperandsByNames(Instruction *I) {
+void IRNormalizer::reorderInstructionOperandsByNames(Instruction *I) const {
   // This method assumes that passed I is commutative,
   // changing the order of operands in other instructions
   // may change the semantics.
@@ -533,7 +532,7 @@ void IRNormalizer::reorderInstructionOperandsByNames(Instruction *I) {
 /// blocks.
 ///
 /// \param PN PHI node to normalize.
-void IRNormalizer::reorderPHIIncomingValues(PHINode *PN) {
+void IRNormalizer::reorderPHIIncomingValues(PHINode *PN) const {
   // Values for further sorting.
   SmallVector<std::pair<Value *, BasicBlock *>, 2> Values;
 
@@ -562,7 +561,7 @@ void IRNormalizer::reorderPHIIncomingValues(PHINode *PN) {
 /// \see isOutput()
 /// \param F Function to collect outputs from.
 SmallVector<Instruction *, 16>
-IRNormalizer::collectOutputInstructions(Function &F) {
+IRNormalizer::collectOutputInstructions(Function &F) const {
   // Output instructions are collected top-down in each function,
   // any change may break the def-use chain in reordering methods.
   SmallVector<Instruction *, 16> Outputs;
@@ -578,7 +577,7 @@ IRNormalizer::collectOutputInstructions(Function &F) {
 /// ReturnInst.
 ///
 /// \param I Considered instruction.
-bool IRNormalizer::isOutput(const Instruction *I) {
+bool IRNormalizer::isOutput(const Instruction *I) const {
   // Outputs are such instructions which may have side effects or is ReturnInst.
   if (I->mayHaveSideEffects() || isa<ReturnInst>(I))
     return true;
@@ -590,7 +589,7 @@ bool IRNormalizer::isOutput(const Instruction *I) {
 /// immediate operands.
 ///
 /// \param I Considered instruction.
-bool IRNormalizer::isInitialInstruction(const Instruction *I) {
+bool IRNormalizer::isInitialInstruction(const Instruction *I) const {
   // Initial instructions are such instructions whose values are used by
   // other instructions, yet they only depend on immediate values.
   return !I->user_empty() && hasOnlyImmediateOperands(I);
@@ -599,7 +598,7 @@ bool IRNormalizer::isInitialInstruction(const Instruction *I) {
 /// Helper method checking whether the instruction has only immediate operands.
 ///
 /// \param I Considered instruction.
-bool IRNormalizer::hasOnlyImmediateOperands(const Instruction *I) {
+bool IRNormalizer::hasOnlyImmediateOperands(const Instruction *I) const {
   for (const auto &OP : I->operands())
     if (isa<Instruction>(OP))
       return false; // Found non-immediate operand (instruction).
@@ -614,7 +613,7 @@ bool IRNormalizer::hasOnlyImmediateOperands(const Instruction *I) {
 /// \param I Considered instruction.
 /// \param Visited Set of visited instructions.
 SetVector<int> IRNormalizer::getOutputFootprint(
-    Instruction *I, SmallPtrSet<const Instruction *, 32> &Visited) {
+    Instruction *I, SmallPtrSet<const Instruction *, 32> &Visited) const {
 
   // Vector containing indexes of outputs (no repetitions),
   // which use I in the order of walking down the def-use tree.
@@ -657,7 +656,7 @@ SetVector<int> IRNormalizer::getOutputFootprint(
 }
 
 PreservedAnalyses IRNormalizerPass::run(Function &F,
-                                        FunctionAnalysisManager &AM) {
+                                        FunctionAnalysisManager &AM) const {
   IRNormalizer{}.runOnFunction(F);
   return PreservedAnalyses::all();
 }

>From 99ba4eec43fe959e8557054857bf813b7254a33d Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Tue, 14 Nov 2023 20:57:44 -0800
Subject: [PATCH 33/50] First draft of new reordering

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp    | 91 +++++++++++++++++--
 .../IRNormalizer/reordering-instructions.ll   |  4 +-
 2 files changed, 86 insertions(+), 9 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 2ce155233df6bf..85230a8beb8fc2 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -30,7 +30,7 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Transforms/Utils.h"
 #include <algorithm>
-#include <vector>
+#include <stack>
 
 #define DEBUG_TYPE "normalize"
 
@@ -74,7 +74,13 @@ class IRNormalizer {
   /// \name Reordering.
   /// @{
   void reorderInstructions(Function &F) const;
-  void reorderInstructionsInBasicBlock(BasicBlock &BB) const;
+  void reorderSourceInstruction(Instruction *I,
+      std::stack<Instruction *> &TopologicalSort, 
+      SmallPtrSet<const Instruction *, 32> &Visited) const;
+  void reorderDefinition(Instruction *Definition,
+      std::stack<Instruction *> &TopologicalSort,
+      SmallPtrSet<const Instruction *, 32> &Visited) const;
+  // TODO: Delete reorderInstruction
   void reorderInstruction(Instruction *Used, Instruction *User,
                           SmallPtrSet<const Instruction *, 32> &Visited) const;
   void reorderInstructionOperandsByNames(Instruction *I) const;
@@ -440,16 +446,87 @@ void IRNormalizer::foldInstructionName(Instruction *I) const {
 ///
 /// \see reorderInstruction()
 void IRNormalizer::reorderInstructions(Function &F) const {
-  SmallPtrSet<const Instruction *, 32> UsedInFunction;
   for (auto &BB : F) {
-    LLVM_DEBUG(dbgs() << "Reordering instructions of basic block: " 
-                      << BB.getName());
-    reorderInstructionsInBasicBlock(BB);
+    LLVM_DEBUG(dbgs() << "Reordering instructions in basic block: " 
+                      << BB.getName() << "\n");
+    // Find the source nodes of the DAG of instructions in this basic block.
+    // We must iterate from the first to the last instruction otherwise side 
+    // effecting instructions could be reordered. 
+
+    std::stack<Instruction *> TopologicalSort;
+    SmallPtrSet<const Instruction *, 32> Visited;
+    for (auto &I : BB) { 
+      if (!isOutput(&I) && !I.isTerminator()) 
+        continue; // I is not a source node. 
+      LLVM_DEBUG(dbgs() << "\tReordering from source instruction: "; I.dump());
+      reorderDefinition(&I, TopologicalSort, Visited);
+    }
+
+    for (auto &I : BB) { 
+      if (Visited.contains(&I)) 
+        continue; // I is not a source node. 
+      LLVM_DEBUG(dbgs() << "\tReordering from source instruction: "; I.dump());
+      reorderDefinition(&I, TopologicalSort, Visited);
+    }
+
+    LLVM_DEBUG(dbgs() << "Inserting instructions into: " << BB.getName() 
+                      << "\n");
+    // Reorder based on the topological sort. 
+    while (!TopologicalSort.empty()) {
+      auto *Instruction = TopologicalSort.top();
+      auto *FirstNonPHIOrDbgOrAlloca = &*BB.getFirstNonPHIOrDbgOrAlloca();
+      // if (Instruction == FirstNonPHIOrDbgOrAlloca) {
+      //   // If the first instruction in the block is the instruction that we're
+      //   // currently trying to insert, then leave it at the top of the block
+      //   // and insert the next instruction above it. 
+      //   TopologicalSort.pop();
+      //   if (TopologicalSort.empty())
+      //     break;
+      //   auto *NextInstruction = TopologicalSort.top();
+      //   LLVM_DEBUG(dbgs() << "\tInserting "; NextInstruction->dump(); 
+      //              dbgs() << "\t\tbefore"; Instruction->dump());
+      //   NextInstruction->moveBefore(Instruction);
+      //   TopologicalSort.pop();
+      // } else {
+      //   LLVM_DEBUG(dbgs() << "\tInserting "; Instruction->dump(); 
+      //              dbgs() << "\t\tafter"; FirstNonPHIOrDbgOrAlloca->dump());
+      //   Instruction->moveAfter(FirstNonPHIOrDbgOrAlloca);
+      //   TopologicalSort.pop();
+      // }
+      Instruction->moveBefore(FirstNonPHIOrDbgOrAlloca);
+        TopologicalSort.pop();
+    }
   }
 }
 
-void IRNormalizer::reorderInstructionsInBasicBlock(BasicBlock &BB) const {
+void IRNormalizer::reorderSourceInstruction(Instruction *I,
+    std::stack<Instruction *> &TopologicalSort,
+    SmallPtrSet<const Instruction *, 32> &Visited) const {
+  LLVM_DEBUG(dbgs() << "\tReordering from source instruction: "; I->dump());
+}
+
+void IRNormalizer::reorderDefinition(Instruction *Definition,
+    std::stack<Instruction *> &TopologicalSort,
+    SmallPtrSet<const Instruction *, 32> &Visited) const {
+  if (Visited.contains(Definition))
+    return;
+  Visited.insert(Definition);
+
+  if (Definition->comesBefore(&*Definition->getParent()
+                                          ->getFirstNonPHIOrDbgOrAlloca()))
+    return; // TODO: Do some kind of ordering for these instructions. 
+
+  for (auto &Operand : Definition->operands()) {
+    if (auto *Op = dyn_cast<Instruction>(Operand)) {
+      if (Op->getParent() != Definition->getParent())
+        continue; // Only reorder instruction within the same basic block
+      reorderDefinition(Op, TopologicalSort, Visited);
+    }
+  }
 
+  LLVM_DEBUG(dbgs() << "\t\tNext in topological sort: "; Definition->dump());
+  if (!Definition->isTerminator())
+    TopologicalSort.emplace(Definition);
 }
 
 /// Reduces def-use distance or places instruction at the end of the basic
diff --git a/llvm/test/Transforms/IRNormalizer/reordering-instructions.ll b/llvm/test/Transforms/IRNormalizer/reordering-instructions.ll
index 8978b01c3caa6d..338fbbe974cce7 100644
--- a/llvm/test/Transforms/IRNormalizer/reordering-instructions.ll
+++ b/llvm/test/Transforms/IRNormalizer/reordering-instructions.ll
@@ -2,10 +2,10 @@
 
 define double @foo(double %a0, double %a1) {
 entry:
-; CHECK: %a
-; CHECK: %c
 ; CHECK: %b
 ; CHECK: %d
+; CHECK: %a
+; CHECK: %c
   %a = fmul double %a0, %a1
   %b = fmul double %a0, 2.000000e+00
   %c = fmul double %a, 6.000000e+00

>From 11769b36c32570eda0ca764a1a5db2526f10d28e Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sun, 19 Nov 2023 17:01:47 -0800
Subject: [PATCH 34/50] New reordering

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 88 +++++-----------------
 1 file changed, 18 insertions(+), 70 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 85230a8beb8fc2..8220217cc6fe44 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -74,15 +74,9 @@ class IRNormalizer {
   /// \name Reordering.
   /// @{
   void reorderInstructions(Function &F) const;
-  void reorderSourceInstruction(Instruction *I,
-      std::stack<Instruction *> &TopologicalSort, 
-      SmallPtrSet<const Instruction *, 32> &Visited) const;
   void reorderDefinition(Instruction *Definition,
       std::stack<Instruction *> &TopologicalSort,
       SmallPtrSet<const Instruction *, 32> &Visited) const;
-  // TODO: Delete reorderInstruction
-  void reorderInstruction(Instruction *Used, Instruction *User,
-                          SmallPtrSet<const Instruction *, 32> &Visited) const;
   void reorderInstructionOperandsByNames(Instruction *I) const;
   void reorderPHIIncomingValues(PHINode *PN) const;
   /// @}
@@ -458,7 +452,8 @@ void IRNormalizer::reorderInstructions(Function &F) const {
     for (auto &I : BB) { 
       if (!isOutput(&I) && !I.isTerminator()) 
         continue; // I is not a source node. 
-      LLVM_DEBUG(dbgs() << "\tReordering from source instruction: "; I.dump());
+      LLVM_DEBUG(dbgs() << "\tReordering from source effecting instruction: "; 
+                 I.dump());
       reorderDefinition(&I, TopologicalSort, Visited);
     }
 
@@ -475,36 +470,12 @@ void IRNormalizer::reorderInstructions(Function &F) const {
     while (!TopologicalSort.empty()) {
       auto *Instruction = TopologicalSort.top();
       auto *FirstNonPHIOrDbgOrAlloca = &*BB.getFirstNonPHIOrDbgOrAlloca();
-      // if (Instruction == FirstNonPHIOrDbgOrAlloca) {
-      //   // If the first instruction in the block is the instruction that we're
-      //   // currently trying to insert, then leave it at the top of the block
-      //   // and insert the next instruction above it. 
-      //   TopologicalSort.pop();
-      //   if (TopologicalSort.empty())
-      //     break;
-      //   auto *NextInstruction = TopologicalSort.top();
-      //   LLVM_DEBUG(dbgs() << "\tInserting "; NextInstruction->dump(); 
-      //              dbgs() << "\t\tbefore"; Instruction->dump());
-      //   NextInstruction->moveBefore(Instruction);
-      //   TopologicalSort.pop();
-      // } else {
-      //   LLVM_DEBUG(dbgs() << "\tInserting "; Instruction->dump(); 
-      //              dbgs() << "\t\tafter"; FirstNonPHIOrDbgOrAlloca->dump());
-      //   Instruction->moveAfter(FirstNonPHIOrDbgOrAlloca);
-      //   TopologicalSort.pop();
-      // }
       Instruction->moveBefore(FirstNonPHIOrDbgOrAlloca);
         TopologicalSort.pop();
     }
   }
 }
 
-void IRNormalizer::reorderSourceInstruction(Instruction *I,
-    std::stack<Instruction *> &TopologicalSort,
-    SmallPtrSet<const Instruction *, 32> &Visited) const {
-  LLVM_DEBUG(dbgs() << "\tReordering from source instruction: "; I->dump());
-}
-
 void IRNormalizer::reorderDefinition(Instruction *Definition,
     std::stack<Instruction *> &TopologicalSort,
     SmallPtrSet<const Instruction *, 32> &Visited) const {
@@ -512,9 +483,14 @@ void IRNormalizer::reorderDefinition(Instruction *Definition,
     return;
   Visited.insert(Definition);
 
-  if (Definition->comesBefore(&*Definition->getParent()
-                                          ->getFirstNonPHIOrDbgOrAlloca()))
-    return; // TODO: Do some kind of ordering for these instructions. 
+  {
+    const auto *BasicBlock = Definition->getParent();
+    const auto FirstNonPHIOrDbgOrAlloca = BasicBlock->getFirstNonPHIOrDbgOrAlloca();
+    if (FirstNonPHIOrDbgOrAlloca == BasicBlock->end())
+      return;
+    if (Definition->comesBefore(&*FirstNonPHIOrDbgOrAlloca))
+      return; // TODO: Do some kind of ordering for these instructions. 
+  }
 
   for (auto &Operand : Definition->operands()) {
     if (auto *Op = dyn_cast<Instruction>(Operand)) {
@@ -525,44 +501,16 @@ void IRNormalizer::reorderDefinition(Instruction *Definition,
   }
 
   LLVM_DEBUG(dbgs() << "\t\tNext in topological sort: "; Definition->dump());
-  if (!Definition->isTerminator())
-    TopologicalSort.emplace(Definition);
-}
-
-/// Reduces def-use distance or places instruction at the end of the basic
-/// block. Continues to walk up the def-use tree recursively. Used by
-/// reorderInstructions().
-///
-/// \see reorderInstructions()
-/// \param Used Pointer to the instruction whose value is used by the \p User.
-/// \param User Pointer to the instruction which uses the \p Used.
-/// \param Visited Set of visited instructions.
-void IRNormalizer::reorderInstruction(
-    Instruction *Used, Instruction *User,
-    SmallPtrSet<const Instruction *, 32> &Visited) const {
-  if (isa<PHINode>(Used))
-    return;
-  if (Visited.contains(Used))
+  if (Definition->isTerminator())
     return;
-  Visited.insert(Used);
-
-  if (Used->getParent() == User->getParent()) {
-    // If Used and User share the same basic block move Used just before User.
-    LLVM_DEBUG(dbgs() << "\tMoved " << *Used << " before " << *User << "\n");
-    Used->moveBefore(User);
-  } else {
-    // Otherwise move Used to the very end of its basic block.
-    LLVM_DEBUG(dbgs() << "\tMoved " << *Used << " to end of block "
-                      << Used->getParent()->getName() << "\n");
-    Used->moveBefore(&Used->getParent()->back());
-  }
-
-  for (auto &OP : Used->operands()) {
-    if (auto *IOP = dyn_cast<Instruction>(OP)) {
-      // Walk up the def-use tree.
-      reorderInstruction(IOP, Used, Visited);
-    }
+  if (auto *Call = dyn_cast<CallInst>(Definition)) {
+    if (Call->isMustTailCall())
+      return;
+    if (Call->getIntrinsicID() == Intrinsic::experimental_deoptimize)
+      return;
   }
+  // TODO: return on llvm.experimental.deopt...
+  TopologicalSort.emplace(Definition);
 }
 
 /// Reorders instruction's operands alphabetically. This method assumes

>From 6ac9081aa983497fa712bd23b419cfbb9009f257 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sun, 19 Nov 2023 17:47:57 -0800
Subject: [PATCH 35/50] Change the output ordering

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 47 +++++++++++++++-------
 1 file changed, 32 insertions(+), 15 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 8220217cc6fe44..045ef08c77ffe0 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -77,6 +77,8 @@ class IRNormalizer {
   void reorderDefinition(Instruction *Definition,
       std::stack<Instruction *> &TopologicalSort,
       SmallPtrSet<const Instruction *, 32> &Visited) const;
+  void reorderBasedOnTopologicalSort(BasicBlock &BB, 
+      std::stack<Instruction *> &TopologicalSort) const;
   void reorderInstructionOperandsByNames(Instruction *I) const;
   void reorderPHIIncomingValues(PHINode *PN) const;
   /// @}
@@ -447,32 +449,35 @@ void IRNormalizer::reorderInstructions(Function &F) const {
     // We must iterate from the first to the last instruction otherwise side 
     // effecting instructions could be reordered. 
 
-    std::stack<Instruction *> TopologicalSort;
     SmallPtrSet<const Instruction *, 32> Visited;
+    std::stack<Instruction *> TopologicalSort;
     for (auto &I : BB) { 
       if (!isOutput(&I) && !I.isTerminator()) 
-        continue; // I is not a source node. 
-      LLVM_DEBUG(dbgs() << "\tReordering from source effecting instruction: "; 
+        continue; // I is not side effecting. 
+      LLVM_DEBUG(dbgs() << "\tReordering from effecting source instruction: "; 
                  I.dump());
       reorderDefinition(&I, TopologicalSort, Visited);
     }
 
+    std::stack<Instruction *> UsedOutsideOfBBTopologicalSort;
+    for (auto &I : BB) { 
+      if (Visited.contains(&I) || !I.isUsedOutsideOfBlock(I.getParent())) 
+        continue;
+      LLVM_DEBUG(dbgs() << "\tReordering from source instruction that's used in another block: "; I.dump());
+      reorderDefinition(&I, UsedOutsideOfBBTopologicalSort, Visited);
+    }
+
     for (auto &I : BB) { 
       if (Visited.contains(&I)) 
-        continue; // I is not a source node. 
-      LLVM_DEBUG(dbgs() << "\tReordering from source instruction: "; I.dump());
+        continue;
+      LLVM_DEBUG(dbgs() << "\tReordering from dead source instruction: "; I.dump());
       reorderDefinition(&I, TopologicalSort, Visited);
     }
 
     LLVM_DEBUG(dbgs() << "Inserting instructions into: " << BB.getName() 
                       << "\n");
-    // Reorder based on the topological sort. 
-    while (!TopologicalSort.empty()) {
-      auto *Instruction = TopologicalSort.top();
-      auto *FirstNonPHIOrDbgOrAlloca = &*BB.getFirstNonPHIOrDbgOrAlloca();
-      Instruction->moveBefore(FirstNonPHIOrDbgOrAlloca);
-        TopologicalSort.pop();
-    }
+    reorderBasedOnTopologicalSort(BB, UsedOutsideOfBBTopologicalSort);
+    reorderBasedOnTopologicalSort(BB, TopologicalSort);
   }
 }
 
@@ -488,7 +493,7 @@ void IRNormalizer::reorderDefinition(Instruction *Definition,
     const auto FirstNonPHIOrDbgOrAlloca = BasicBlock->getFirstNonPHIOrDbgOrAlloca();
     if (FirstNonPHIOrDbgOrAlloca == BasicBlock->end())
       return;
-    if (Definition->comesBefore(&*FirstNonPHIOrDbgOrAlloca))
+    else if (Definition->comesBefore(&*FirstNonPHIOrDbgOrAlloca))
       return; // TODO: Do some kind of ordering for these instructions. 
   }
 
@@ -500,7 +505,7 @@ void IRNormalizer::reorderDefinition(Instruction *Definition,
     }
   }
 
-  LLVM_DEBUG(dbgs() << "\t\tNext in topological sort: "; Definition->dump());
+  // Don't reorder certain instructions. 
   if (Definition->isTerminator())
     return;
   if (auto *Call = dyn_cast<CallInst>(Definition)) {
@@ -509,10 +514,22 @@ void IRNormalizer::reorderDefinition(Instruction *Definition,
     if (Call->getIntrinsicID() == Intrinsic::experimental_deoptimize)
       return;
   }
-  // TODO: return on llvm.experimental.deopt...
+
+  LLVM_DEBUG(dbgs() << "\t\tNext in topological sort: "; Definition->dump());
   TopologicalSort.emplace(Definition);
 }
 
+void IRNormalizer::reorderBasedOnTopologicalSort(BasicBlock &BB, 
+    std::stack<Instruction *> &TopologicalSort) const {
+  // Reorder based on the topological sort. 
+  while (!TopologicalSort.empty()) {
+    auto *Instruction = TopologicalSort.top();
+    auto *FirstNonPHIOrDbgOrAlloca = &*BB.getFirstNonPHIOrDbgOrAlloca();
+    Instruction->moveBefore(FirstNonPHIOrDbgOrAlloca);
+      TopologicalSort.pop();
+  }
+}
+
 /// Reorders instruction's operands alphabetically. This method assumes
 /// that passed instruction is commutative. Changing the operand order
 /// in other instructions may change the semantics.

>From 27acbf65540186bfcab8ec3723438b6d56478fc1 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sun, 19 Nov 2023 17:51:33 -0800
Subject: [PATCH 36/50] Add comments

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 045ef08c77ffe0..f5371aafe321a8 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -474,6 +474,10 @@ void IRNormalizer::reorderInstructions(Function &F) const {
       reorderDefinition(&I, TopologicalSort, Visited);
     }
 
+    // Output order should be:
+    // 1 - Unused Instructions.
+    // 2 - Side effecting instructions .
+    // 3 - Instructions used outside of the basic block.
     LLVM_DEBUG(dbgs() << "Inserting instructions into: " << BB.getName() 
                       << "\n");
     reorderBasedOnTopologicalSort(BB, UsedOutsideOfBBTopologicalSort);
@@ -489,12 +493,14 @@ void IRNormalizer::reorderDefinition(Instruction *Definition,
   Visited.insert(Definition);
 
   {
+    // TODO: Do some kind of ordering for instructions that come before the 
+    // result of getFirstNonPHIOrDbgOrAlloca().
     const auto *BasicBlock = Definition->getParent();
     const auto FirstNonPHIOrDbgOrAlloca = BasicBlock->getFirstNonPHIOrDbgOrAlloca();
     if (FirstNonPHIOrDbgOrAlloca == BasicBlock->end())
       return;
     else if (Definition->comesBefore(&*FirstNonPHIOrDbgOrAlloca))
-      return; // TODO: Do some kind of ordering for these instructions. 
+      return; 
   }
 
   for (auto &Operand : Definition->operands()) {

>From 4a6be27d9bce682f710cafddde5d39af04d20509 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sun, 19 Nov 2023 18:21:56 -0800
Subject: [PATCH 37/50] Revert "Add comments"

This reverts commit dd8d2846a62b099127fcb5cb2ba4b231f317747a.
---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index f5371aafe321a8..045ef08c77ffe0 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -474,10 +474,6 @@ void IRNormalizer::reorderInstructions(Function &F) const {
       reorderDefinition(&I, TopologicalSort, Visited);
     }
 
-    // Output order should be:
-    // 1 - Unused Instructions.
-    // 2 - Side effecting instructions .
-    // 3 - Instructions used outside of the basic block.
     LLVM_DEBUG(dbgs() << "Inserting instructions into: " << BB.getName() 
                       << "\n");
     reorderBasedOnTopologicalSort(BB, UsedOutsideOfBBTopologicalSort);
@@ -493,14 +489,12 @@ void IRNormalizer::reorderDefinition(Instruction *Definition,
   Visited.insert(Definition);
 
   {
-    // TODO: Do some kind of ordering for instructions that come before the 
-    // result of getFirstNonPHIOrDbgOrAlloca().
     const auto *BasicBlock = Definition->getParent();
     const auto FirstNonPHIOrDbgOrAlloca = BasicBlock->getFirstNonPHIOrDbgOrAlloca();
     if (FirstNonPHIOrDbgOrAlloca == BasicBlock->end())
       return;
     else if (Definition->comesBefore(&*FirstNonPHIOrDbgOrAlloca))
-      return; 
+      return; // TODO: Do some kind of ordering for these instructions. 
   }
 
   for (auto &Operand : Definition->operands()) {

>From 2bbc0bbefe3aa4fe014c2983014a763555fcadbd Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sun, 19 Nov 2023 18:22:17 -0800
Subject: [PATCH 38/50] Revert "Change the output ordering"

This reverts commit b1d6ef875221c1a32481592c3c1d92abc2dd1126.
---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 47 +++++++---------------
 1 file changed, 15 insertions(+), 32 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 045ef08c77ffe0..8220217cc6fe44 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -77,8 +77,6 @@ class IRNormalizer {
   void reorderDefinition(Instruction *Definition,
       std::stack<Instruction *> &TopologicalSort,
       SmallPtrSet<const Instruction *, 32> &Visited) const;
-  void reorderBasedOnTopologicalSort(BasicBlock &BB, 
-      std::stack<Instruction *> &TopologicalSort) const;
   void reorderInstructionOperandsByNames(Instruction *I) const;
   void reorderPHIIncomingValues(PHINode *PN) const;
   /// @}
@@ -449,35 +447,32 @@ void IRNormalizer::reorderInstructions(Function &F) const {
     // We must iterate from the first to the last instruction otherwise side 
     // effecting instructions could be reordered. 
 
-    SmallPtrSet<const Instruction *, 32> Visited;
     std::stack<Instruction *> TopologicalSort;
+    SmallPtrSet<const Instruction *, 32> Visited;
     for (auto &I : BB) { 
       if (!isOutput(&I) && !I.isTerminator()) 
-        continue; // I is not side effecting. 
-      LLVM_DEBUG(dbgs() << "\tReordering from effecting source instruction: "; 
+        continue; // I is not a source node. 
+      LLVM_DEBUG(dbgs() << "\tReordering from source effecting instruction: "; 
                  I.dump());
       reorderDefinition(&I, TopologicalSort, Visited);
     }
 
-    std::stack<Instruction *> UsedOutsideOfBBTopologicalSort;
-    for (auto &I : BB) { 
-      if (Visited.contains(&I) || !I.isUsedOutsideOfBlock(I.getParent())) 
-        continue;
-      LLVM_DEBUG(dbgs() << "\tReordering from source instruction that's used in another block: "; I.dump());
-      reorderDefinition(&I, UsedOutsideOfBBTopologicalSort, Visited);
-    }
-
     for (auto &I : BB) { 
       if (Visited.contains(&I)) 
-        continue;
-      LLVM_DEBUG(dbgs() << "\tReordering from dead source instruction: "; I.dump());
+        continue; // I is not a source node. 
+      LLVM_DEBUG(dbgs() << "\tReordering from source instruction: "; I.dump());
       reorderDefinition(&I, TopologicalSort, Visited);
     }
 
     LLVM_DEBUG(dbgs() << "Inserting instructions into: " << BB.getName() 
                       << "\n");
-    reorderBasedOnTopologicalSort(BB, UsedOutsideOfBBTopologicalSort);
-    reorderBasedOnTopologicalSort(BB, TopologicalSort);
+    // Reorder based on the topological sort. 
+    while (!TopologicalSort.empty()) {
+      auto *Instruction = TopologicalSort.top();
+      auto *FirstNonPHIOrDbgOrAlloca = &*BB.getFirstNonPHIOrDbgOrAlloca();
+      Instruction->moveBefore(FirstNonPHIOrDbgOrAlloca);
+        TopologicalSort.pop();
+    }
   }
 }
 
@@ -493,7 +488,7 @@ void IRNormalizer::reorderDefinition(Instruction *Definition,
     const auto FirstNonPHIOrDbgOrAlloca = BasicBlock->getFirstNonPHIOrDbgOrAlloca();
     if (FirstNonPHIOrDbgOrAlloca == BasicBlock->end())
       return;
-    else if (Definition->comesBefore(&*FirstNonPHIOrDbgOrAlloca))
+    if (Definition->comesBefore(&*FirstNonPHIOrDbgOrAlloca))
       return; // TODO: Do some kind of ordering for these instructions. 
   }
 
@@ -505,7 +500,7 @@ void IRNormalizer::reorderDefinition(Instruction *Definition,
     }
   }
 
-  // Don't reorder certain instructions. 
+  LLVM_DEBUG(dbgs() << "\t\tNext in topological sort: "; Definition->dump());
   if (Definition->isTerminator())
     return;
   if (auto *Call = dyn_cast<CallInst>(Definition)) {
@@ -514,22 +509,10 @@ void IRNormalizer::reorderDefinition(Instruction *Definition,
     if (Call->getIntrinsicID() == Intrinsic::experimental_deoptimize)
       return;
   }
-
-  LLVM_DEBUG(dbgs() << "\t\tNext in topological sort: "; Definition->dump());
+  // TODO: return on llvm.experimental.deopt...
   TopologicalSort.emplace(Definition);
 }
 
-void IRNormalizer::reorderBasedOnTopologicalSort(BasicBlock &BB, 
-    std::stack<Instruction *> &TopologicalSort) const {
-  // Reorder based on the topological sort. 
-  while (!TopologicalSort.empty()) {
-    auto *Instruction = TopologicalSort.top();
-    auto *FirstNonPHIOrDbgOrAlloca = &*BB.getFirstNonPHIOrDbgOrAlloca();
-    Instruction->moveBefore(FirstNonPHIOrDbgOrAlloca);
-      TopologicalSort.pop();
-  }
-}
-
 /// Reorders instruction's operands alphabetically. This method assumes
 /// that passed instruction is commutative. Changing the operand order
 /// in other instructions may change the semantics.

>From 8aa1e05756b6ceeb721cb70a26541340b8ec53b2 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sun, 19 Nov 2023 18:30:35 -0800
Subject: [PATCH 39/50] clang-format

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 39 +++++++++++-----------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 8220217cc6fe44..8608e6ff1593e0 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -75,8 +75,8 @@ class IRNormalizer {
   /// @{
   void reorderInstructions(Function &F) const;
   void reorderDefinition(Instruction *Definition,
-      std::stack<Instruction *> &TopologicalSort,
-      SmallPtrSet<const Instruction *, 32> &Visited) const;
+                         std::stack<Instruction *> &TopologicalSort,
+                         SmallPtrSet<const Instruction *, 32> &Visited) const;
   void reorderInstructionOperandsByNames(Instruction *I) const;
   void reorderPHIIncomingValues(PHINode *PN) const;
   /// @}
@@ -441,43 +441,43 @@ void IRNormalizer::foldInstructionName(Instruction *I) const {
 /// \see reorderInstruction()
 void IRNormalizer::reorderInstructions(Function &F) const {
   for (auto &BB : F) {
-    LLVM_DEBUG(dbgs() << "Reordering instructions in basic block: " 
+    LLVM_DEBUG(dbgs() << "Reordering instructions in basic block: "
                       << BB.getName() << "\n");
     // Find the source nodes of the DAG of instructions in this basic block.
-    // We must iterate from the first to the last instruction otherwise side 
-    // effecting instructions could be reordered. 
+    // We must iterate from the first to the last instruction otherwise side
+    // effecting instructions could be reordered.
 
     std::stack<Instruction *> TopologicalSort;
     SmallPtrSet<const Instruction *, 32> Visited;
-    for (auto &I : BB) { 
-      if (!isOutput(&I) && !I.isTerminator()) 
-        continue; // I is not a source node. 
-      LLVM_DEBUG(dbgs() << "\tReordering from source effecting instruction: "; 
+    for (auto &I : BB) {
+      if (!isOutput(&I) && !I.isTerminator())
+        continue; // I is not a source node.
+      LLVM_DEBUG(dbgs() << "\tReordering from source effecting instruction: ";
                  I.dump());
       reorderDefinition(&I, TopologicalSort, Visited);
     }
 
-    for (auto &I : BB) { 
-      if (Visited.contains(&I)) 
-        continue; // I is not a source node. 
+    for (auto &I : BB) {
+      if (Visited.contains(&I))
+        continue; // I is not a source node.
       LLVM_DEBUG(dbgs() << "\tReordering from source instruction: "; I.dump());
       reorderDefinition(&I, TopologicalSort, Visited);
     }
 
-    LLVM_DEBUG(dbgs() << "Inserting instructions into: " << BB.getName() 
+    LLVM_DEBUG(dbgs() << "Inserting instructions into: " << BB.getName()
                       << "\n");
-    // Reorder based on the topological sort. 
+    // Reorder based on the topological sort.
     while (!TopologicalSort.empty()) {
       auto *Instruction = TopologicalSort.top();
       auto *FirstNonPHIOrDbgOrAlloca = &*BB.getFirstNonPHIOrDbgOrAlloca();
       Instruction->moveBefore(FirstNonPHIOrDbgOrAlloca);
-        TopologicalSort.pop();
+      TopologicalSort.pop();
     }
   }
 }
 
-void IRNormalizer::reorderDefinition(Instruction *Definition,
-    std::stack<Instruction *> &TopologicalSort,
+void IRNormalizer::reorderDefinition(
+    Instruction *Definition, std::stack<Instruction *> &TopologicalSort,
     SmallPtrSet<const Instruction *, 32> &Visited) const {
   if (Visited.contains(Definition))
     return;
@@ -485,11 +485,12 @@ void IRNormalizer::reorderDefinition(Instruction *Definition,
 
   {
     const auto *BasicBlock = Definition->getParent();
-    const auto FirstNonPHIOrDbgOrAlloca = BasicBlock->getFirstNonPHIOrDbgOrAlloca();
+    const auto FirstNonPHIOrDbgOrAlloca =
+        BasicBlock->getFirstNonPHIOrDbgOrAlloca();
     if (FirstNonPHIOrDbgOrAlloca == BasicBlock->end())
       return;
     if (Definition->comesBefore(&*FirstNonPHIOrDbgOrAlloca))
-      return; // TODO: Do some kind of ordering for these instructions. 
+      return; // TODO: Do some kind of ordering for these instructions.
   }
 
   for (auto &Operand : Definition->operands()) {

>From 11d83a98ee0a3e25964e1d224c522a0ff0309adb Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sun, 19 Nov 2023 19:52:35 -0800
Subject: [PATCH 40/50] Don't reorder bitcasts the precede musttail

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 8608e6ff1593e0..6bbe4106a517fd 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -510,7 +510,13 @@ void IRNormalizer::reorderDefinition(
     if (Call->getIntrinsicID() == Intrinsic::experimental_deoptimize)
       return;
   }
-  // TODO: return on llvm.experimental.deopt...
+  if (auto *BitCast = dyn_cast<BitCastInst>(Definition)) {
+    if (auto *Call = dyn_cast<CallInst>(BitCast->getOperand(0))) {
+      if (Call->isMustTailCall())
+        return;
+    }
+  }
+
   TopologicalSort.emplace(Definition);
 }
 

>From bf78a5b03e6a9bd40724a7272f3b1749755df4e7 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Wed, 13 Mar 2024 20:51:38 -0700
Subject: [PATCH 41/50] Fixup rebase

---
 llvm/docs/ReleaseNotes.rst       |  2 ++
 llvm/lib/Passes/PassRegistry.def | 13 +------------
 2 files changed, 3 insertions(+), 12 deletions(-)

diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index f5f3fedd02e099..c7c351f86ce28e 100644
--- a/llvm/docs/ReleaseNotes.rst
+++ b/llvm/docs/ReleaseNotes.rst
@@ -47,6 +47,8 @@ Non-comprehensive list of changes in this release
   same semantics. The normalizer makes it easier to spot semantic differences
   when diffing two modules which have undergone different passes.
 
+* ...
+
 Update on required toolchains to build LLVM
 -------------------------------------------
 
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
index b90729efb2b7b3..daf09e0183c534 100644
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -312,9 +312,6 @@ FUNCTION_PASS("bounds-checking", BoundsCheckingPass())
 FUNCTION_PASS("break-crit-edges", BreakCriticalEdgesPass())
 FUNCTION_PASS("callbr-prepare", CallBrPreparePass())
 FUNCTION_PASS("callsite-splitting", CallSiteSplittingPass())
-FUNCTION_PASS("consthoist", ConstantHoistingPass())
-FUNCTION_PASS("count-visits", CountVisitsPass())
-FUNCTION_PASS("constraint-elimination", ConstraintEliminationPass())
 FUNCTION_PASS("chr", ControlHeightReductionPass())
 FUNCTION_PASS("codegenprepare", CodeGenPreparePass(TM))
 FUNCTION_PASS("consthoist", ConstantHoistingPass())
@@ -387,16 +384,8 @@ FUNCTION_PASS("mergereturn", UnifyFunctionExitNodesPass())
 FUNCTION_PASS("move-auto-init", MoveAutoInitPass())
 FUNCTION_PASS("nary-reassociate", NaryReassociatePass())
 FUNCTION_PASS("newgvn", NewGVNPass())
+FUNCTION_PASS("no-op-function", NoOpFunctionPass())
 FUNCTION_PASS("normalize", IRNormalizerPass())
-FUNCTION_PASS("jump-threading", JumpThreadingPass())
-FUNCTION_PASS("partially-inline-libcalls", PartiallyInlineLibCallsPass())
-FUNCTION_PASS("kcfi", KCFIPass())
-FUNCTION_PASS("lcssa", LCSSAPass())
-FUNCTION_PASS("loop-data-prefetch", LoopDataPrefetchPass())
-FUNCTION_PASS("loop-load-elim", LoopLoadEliminationPass())
-FUNCTION_PASS("loop-fusion", LoopFusePass())
-FUNCTION_PASS("loop-distribute", LoopDistributePass())
-FUNCTION_PASS("loop-versioning", LoopVersioningPass())
 FUNCTION_PASS("objc-arc", ObjCARCOptPass())
 FUNCTION_PASS("objc-arc-contract", ObjCARCContractPass())
 FUNCTION_PASS("objc-arc-expand", ObjCARCExpandPass())

>From da4601575b63b4bd3c2ffc699701accd1307dbd0 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Thu, 14 Mar 2024 19:25:00 -0700
Subject: [PATCH 42/50] Add regression tests

---
 .../IRNormalizer/regression-coro-elide-musttail.ll  | 13 +++++++++++++
 .../IRNormalizer/regression-deoptimize.ll           | 11 +++++++++++
 .../regression-dont-hoist-deoptimize.ll             | 13 +++++++++++++
 3 files changed, 37 insertions(+)
 create mode 100644 llvm/test/Transforms/IRNormalizer/regression-coro-elide-musttail.ll
 create mode 100644 llvm/test/Transforms/IRNormalizer/regression-deoptimize.ll
 create mode 100644 llvm/test/Transforms/IRNormalizer/regression-dont-hoist-deoptimize.ll

diff --git a/llvm/test/Transforms/IRNormalizer/regression-coro-elide-musttail.ll b/llvm/test/Transforms/IRNormalizer/regression-coro-elide-musttail.ll
new file mode 100644
index 00000000000000..e24f4d8c5f5c57
--- /dev/null
+++ b/llvm/test/Transforms/IRNormalizer/regression-coro-elide-musttail.ll
@@ -0,0 +1,13 @@
+; RUN: opt < %s -passes=normalize -verify-each
+
+define fastcc void @foo.resume_musttail(ptr %FramePtr) {
+entry:
+  %0 = tail call token @llvm.coro.id(i32 0, ptr null, ptr null, ptr null)
+  musttail call fastcc void undef(ptr null)
+  ret void
+}
+
+; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: read)
+declare token @llvm.coro.id(i32, ptr readnone, ptr nocapture readonly, ptr) #0
+
+attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: read) }
diff --git a/llvm/test/Transforms/IRNormalizer/regression-deoptimize.ll b/llvm/test/Transforms/IRNormalizer/regression-deoptimize.ll
new file mode 100644
index 00000000000000..b4bda7dd7d7674
--- /dev/null
+++ b/llvm/test/Transforms/IRNormalizer/regression-deoptimize.ll
@@ -0,0 +1,11 @@
+; RUN: opt < %s -passes=normalize -verify-each
+
+target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:32-f32:32:32-f64:32:32-v64:32:64-v128:32:128-a0:0:32-n32"
+
+define void @test1() {
+  %1 = load i8, ptr null, align 1
+  call void (...) @llvm.experimental.deoptimize.isVoid() [ "deopt"() ]
+  ret void
+}
+
+declare void @llvm.experimental.deoptimize.isVoid(...)
diff --git a/llvm/test/Transforms/IRNormalizer/regression-dont-hoist-deoptimize.ll b/llvm/test/Transforms/IRNormalizer/regression-dont-hoist-deoptimize.ll
new file mode 100644
index 00000000000000..9ec82f3a18690d
--- /dev/null
+++ b/llvm/test/Transforms/IRNormalizer/regression-dont-hoist-deoptimize.ll
@@ -0,0 +1,13 @@
+; RUN: opt %s -passes=normalize -verify-each
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128-ni:1-p2:32:8:8:32-ni:2"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.experimental.deoptimize.isVoid(...)
+
+define void @widget() {
+bb:
+  %tmp3 = trunc i64 0 to i32
+  call void (...) @llvm.experimental.deoptimize.isVoid(i32 0) [ "deopt"() ]
+  ret void
+}
+

>From 3e2c06dc6b1b4ceda8a064a78daca6b1f29a78f7 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Thu, 14 Mar 2024 19:33:32 -0700
Subject: [PATCH 43/50] Add TODO for future work

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp                      | 2 ++
 .../Transforms/IRNormalizer/regression-dont-hoist-deoptimize.ll | 1 -
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 6bbe4106a517fd..26c46cde09b37f 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -122,6 +122,8 @@ bool IRNormalizer::runOnFunction(Function &F) {
   if (!PreserveOrder)
     reorderInstructions(F);
 
+  // TODO: Reorder basic blocks via a topological sort.
+
   for (auto &I : Outputs)
     nameInstruction(I);
 
diff --git a/llvm/test/Transforms/IRNormalizer/regression-dont-hoist-deoptimize.ll b/llvm/test/Transforms/IRNormalizer/regression-dont-hoist-deoptimize.ll
index 9ec82f3a18690d..e218d8f67d8870 100644
--- a/llvm/test/Transforms/IRNormalizer/regression-dont-hoist-deoptimize.ll
+++ b/llvm/test/Transforms/IRNormalizer/regression-dont-hoist-deoptimize.ll
@@ -10,4 +10,3 @@ bb:
   call void (...) @llvm.experimental.deoptimize.isVoid(i32 0) [ "deopt"() ]
   ret void
 }
-

>From 79253a0679c1d834e6e4d56195919a9ac9e701f4 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Thu, 14 Mar 2024 20:12:54 -0700
Subject: [PATCH 44/50] Stash clang changes

---
 clang/lib/CodeGen/BackendUtil.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 22c3f8642ad8eb..d08d485e6e66bc 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -86,6 +86,7 @@
 #include "llvm/Transforms/Scalar/JumpThreading.h"
 #include "llvm/Transforms/Utils/Debugify.h"
 #include "llvm/Transforms/Utils/EntryExitInstrumenter.h"
+#include "llvm/Transforms/Utils/IRNormalizer.h"
 #include "llvm/Transforms/Utils/ModuleUtils.h"
 #include <memory>
 #include <optional>
@@ -1061,6 +1062,8 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
   if (ClRelinkBuiltinBitcodePostop)
     MPM.addPass(LinkInModulesPass(BC, false));
 
+  MPM.addPass(createModuleToFunctionPassAdaptor(IRNormalizerPass()));
+
   // Add a verifier pass if requested. We don't have to do this if the action
   // requires code generation because there will already be a verifier pass in
   // the code-generation pipeline.

>From 470cae58315da551e3e72a0853612aead53855a4 Mon Sep 17 00:00:00 2001
From: Justin Fargnoli <jfargnoli at nvidia.com>
Date: Sat, 4 May 2024 18:08:16 -0700
Subject: [PATCH 45/50] Condense tests

---
 .../IRNormalizer/naming-basic-blocks.ll       |  8 --------
 .../{naming-instructions.ll => naming.ll}     |  7 +++++++
 ...phi-node-values.ll => reordering-basic.ll} | 20 +++++++++++++++++--
 .../IRNormalizer/reordering-instructions.ll   | 14 -------------
 .../Transforms/IRNormalizer/reordering.ll     |  5 +++++
 5 files changed, 30 insertions(+), 24 deletions(-)
 delete mode 100644 llvm/test/Transforms/IRNormalizer/naming-basic-blocks.ll
 rename llvm/test/Transforms/IRNormalizer/{naming-instructions.ll => naming.ll} (77%)
 rename llvm/test/Transforms/IRNormalizer/{reordering-phi-node-values.ll => reordering-basic.ll} (60%)
 delete mode 100644 llvm/test/Transforms/IRNormalizer/reordering-instructions.ll
 create mode 100644 llvm/test/Transforms/IRNormalizer/reordering.ll

diff --git a/llvm/test/Transforms/IRNormalizer/naming-basic-blocks.ll b/llvm/test/Transforms/IRNormalizer/naming-basic-blocks.ll
deleted file mode 100644
index 9493b3f70ef763..00000000000000
--- a/llvm/test/Transforms/IRNormalizer/naming-basic-blocks.ll
+++ /dev/null
@@ -1,8 +0,0 @@
-; RUN: opt -S -passes=normalize -norm-rename-all < %s | FileCheck %s
-
-define i32 @foo(i32 %a0) {
-; CHECK: bb{{([0-9]{5})}}
-entry:
-  %a = add i32 %a0, 2
-  ret i32 %a
-}
diff --git a/llvm/test/Transforms/IRNormalizer/naming-instructions.ll b/llvm/test/Transforms/IRNormalizer/naming.ll
similarity index 77%
rename from llvm/test/Transforms/IRNormalizer/naming-instructions.ll
rename to llvm/test/Transforms/IRNormalizer/naming.ll
index c08ef18f948c83..9ef718a090f553 100644
--- a/llvm/test/Transforms/IRNormalizer/naming-instructions.ll
+++ b/llvm/test/Transforms/IRNormalizer/naming.ll
@@ -1,5 +1,12 @@
 ; RUN: opt -S -passes=normalize -norm-rename-all < %s | FileCheck %s
 
+define i32 @foo(i32 %a0) {
+; CHECK: bb{{([0-9]{5})}}
+entry:
+  %a = add i32 %a0, 2
+  ret i32 %a
+}
+
 define i32 @foo(i32 %a0) {
 entry:
 ; CHECK: %"vl{{([0-9]{5})}}(%a0, 2)"
diff --git a/llvm/test/Transforms/IRNormalizer/reordering-phi-node-values.ll b/llvm/test/Transforms/IRNormalizer/reordering-basic.ll
similarity index 60%
rename from llvm/test/Transforms/IRNormalizer/reordering-phi-node-values.ll
rename to llvm/test/Transforms/IRNormalizer/reordering-basic.ll
index cba92e8eaf9ac5..59cf3900a6a946 100644
--- a/llvm/test/Transforms/IRNormalizer/reordering-phi-node-values.ll
+++ b/llvm/test/Transforms/IRNormalizer/reordering-basic.ll
@@ -1,16 +1,31 @@
 ; RUN: opt -S -passes=normalize < %s | FileCheck %s
 
-declare double @foo()
+define double @foo(double %a0, double %a1) {
+; CHECK-LABEL: foo(
+entry:
+; CHECK: %b
+; CHECK: %d
+; CHECK: %a
+; CHECK: %c
+  %a = fmul double %a0, %a1
+  %b = fmul double %a0, 2.000000e+00
+  %c = fmul double %a, 6.000000e+00
+  %d = fmul double %b, 6.000000e+00
+  ret double %d
+}
+
+declare double @bir()
 
 declare double @bar()
 
 define double @baz(double %x) {
+; CHECK-LABEL: baz(
 entry:
   %ifcond = fcmp one double %x, 0.000000e+00
   br i1 %ifcond, label %then, label %else
 
 then:       ; preds = %entry
-  %calltmp = call double @foo()
+  %calltmp = call double @bir()
   br label %ifcont
 
 else:       ; preds = %entry
@@ -22,3 +37,4 @@ ifcont:     ; preds = %else, %then
   %iftmp = phi double [ %calltmp, %then ], [ %calltmp1, %else ]
   ret double %iftmp
 }
+
diff --git a/llvm/test/Transforms/IRNormalizer/reordering-instructions.ll b/llvm/test/Transforms/IRNormalizer/reordering-instructions.ll
deleted file mode 100644
index 338fbbe974cce7..00000000000000
--- a/llvm/test/Transforms/IRNormalizer/reordering-instructions.ll
+++ /dev/null
@@ -1,14 +0,0 @@
-; RUN: opt -S -passes=normalize < %s | FileCheck %s
-
-define double @foo(double %a0, double %a1) {
-entry:
-; CHECK: %b
-; CHECK: %d
-; CHECK: %a
-; CHECK: %c
-  %a = fmul double %a0, %a1
-  %b = fmul double %a0, 2.000000e+00
-  %c = fmul double %a, 6.000000e+00
-  %d = fmul double %b, 6.000000e+00
-  ret double %d
-}
diff --git a/llvm/test/Transforms/IRNormalizer/reordering.ll b/llvm/test/Transforms/IRNormalizer/reordering.ll
new file mode 100644
index 00000000000000..1cca67427b533d
--- /dev/null
+++ b/llvm/test/Transforms/IRNormalizer/reordering.ll
@@ -0,0 +1,5 @@
+; RUN: opt -S -passes=normalize < %s | FileCheck %s
+
+define void @foo() {
+  ret void
+}
\ No newline at end of file

>From 19d0ffce4b96d31579647463a02f6d35a502a7ea Mon Sep 17 00:00:00 2001
From: Justin Fargnoli <jfargnoli at nvidia.com>
Date: Sun, 5 May 2024 12:24:59 -0700
Subject: [PATCH 46/50] Elaborate comment

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index 26c46cde09b37f..ee28e2133bd08a 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -446,22 +446,27 @@ void IRNormalizer::reorderInstructions(Function &F) const {
     LLVM_DEBUG(dbgs() << "Reordering instructions in basic block: "
                       << BB.getName() << "\n");
     // Find the source nodes of the DAG of instructions in this basic block.
+    // Source nodes are instructions that have side effects, are terminators, or 
+    // don't have a parent in the DAG of instructions.
+    //
     // We must iterate from the first to the last instruction otherwise side
     // effecting instructions could be reordered.
 
     std::stack<Instruction *> TopologicalSort;
     SmallPtrSet<const Instruction *, 32> Visited;
     for (auto &I : BB) {
+      // First process side effecting and terminating instructions.
       if (!isOutput(&I) && !I.isTerminator())
-        continue; // I is not a source node.
+        continue;
       LLVM_DEBUG(dbgs() << "\tReordering from source effecting instruction: ";
                  I.dump());
       reorderDefinition(&I, TopologicalSort, Visited);
     }
 
     for (auto &I : BB) {
+      // Process the remaining dead instructions.
       if (Visited.contains(&I))
-        continue; // I is not a source node.
+        continue;
       LLVM_DEBUG(dbgs() << "\tReordering from source instruction: "; I.dump());
       reorderDefinition(&I, TopologicalSort, Visited);
     }

>From c7da5cbec117b066d02213279543e5c86e7d2f12 Mon Sep 17 00:00:00 2001
From: Justin Fargnoli <jfargnoli at nvidia.com>
Date: Sun, 5 May 2024 12:25:18 -0700
Subject: [PATCH 47/50] Fix naming.ll

---
 llvm/test/Transforms/IRNormalizer/naming.ll | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/test/Transforms/IRNormalizer/naming.ll b/llvm/test/Transforms/IRNormalizer/naming.ll
index 9ef718a090f553..9f9b033b6a5855 100644
--- a/llvm/test/Transforms/IRNormalizer/naming.ll
+++ b/llvm/test/Transforms/IRNormalizer/naming.ll
@@ -7,7 +7,7 @@ entry:
   ret i32 %a
 }
 
-define i32 @foo(i32 %a0) {
+define i32 @bar(i32 %a0) {
 entry:
 ; CHECK: %"vl{{([0-9]{5})}}(%a0, 2)"
   %a = add i32 %a0, 2

>From b6630609c5315c1e42442ed082f6b80289f9af62 Mon Sep 17 00:00:00 2001
From: Justin Fargnoli <jfargnoli at nvidia.com>
Date: Mon, 6 May 2024 19:23:46 -0700
Subject: [PATCH 48/50] Add TODOs

---
 llvm/lib/Transforms/Utils/IRNormalizer.cpp | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/IRNormalizer.cpp b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
index ee28e2133bd08a..59686d7f8d06ba 100644
--- a/llvm/lib/Transforms/Utils/IRNormalizer.cpp
+++ b/llvm/lib/Transforms/Utils/IRNormalizer.cpp
@@ -45,7 +45,7 @@ class IRNormalizer {
   /// Preserves original order of instructions.
   static cl::opt<bool> PreserveOrder;
   /// Renames all instructions (including user-named).
-  static cl::opt<bool> RenameAll;
+  static cl::opt<bool> RenameAll; // TODO: Don't rename on empty name
   /// Folds all regular instructions (including pre-outputs).
   static cl::opt<bool> FoldPreOutputs;
   /// Sorts and reorders operands in commutative instructions.
@@ -464,7 +464,12 @@ void IRNormalizer::reorderInstructions(Function &F) const {
     }
 
     for (auto &I : BB) {
-      // Process the remaining dead instructions.
+      // Process the remaining instructions.
+      //
+      // TODO: Do more a intelligent sorting of these instructions. For example,
+      // seperate between dead instructinos and instructions used in another 
+      // block. Use properties of the CFG the order instructions that are used 
+      // in another block. 
       if (Visited.contains(&I))
         continue;
       LLVM_DEBUG(dbgs() << "\tReordering from source instruction: "; I.dump());
@@ -495,7 +500,7 @@ void IRNormalizer::reorderDefinition(
     const auto FirstNonPHIOrDbgOrAlloca =
         BasicBlock->getFirstNonPHIOrDbgOrAlloca();
     if (FirstNonPHIOrDbgOrAlloca == BasicBlock->end())
-      return;
+      return; // TODO: Is this necessary?
     if (Definition->comesBefore(&*FirstNonPHIOrDbgOrAlloca))
       return; // TODO: Do some kind of ordering for these instructions.
   }

>From 50ae53381b04daff2f1b2198a3f37970cf985ac9 Mon Sep 17 00:00:00 2001
From: Justin Fargnoli <jfargnoli at nvidia.com>
Date: Mon, 6 May 2024 19:24:04 -0700
Subject: [PATCH 49/50] Prefix infinite-loop.ll with regression

---
 .../{infinite-loop.ll => regression-infinite-loop.ll}             | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename llvm/test/Transforms/IRNormalizer/{infinite-loop.ll => regression-infinite-loop.ll} (100%)

diff --git a/llvm/test/Transforms/IRNormalizer/infinite-loop.ll b/llvm/test/Transforms/IRNormalizer/regression-infinite-loop.ll
similarity index 100%
rename from llvm/test/Transforms/IRNormalizer/infinite-loop.ll
rename to llvm/test/Transforms/IRNormalizer/regression-infinite-loop.ll

>From 0b63a2ef9e4c19b549f7bd030662b34b6d83342d Mon Sep 17 00:00:00 2001
From: Justin Fargnoli <jfargnoli at nvidia.com>
Date: Mon, 6 May 2024 19:24:14 -0700
Subject: [PATCH 50/50] Add first set of reordering tests

---
 .../Transforms/IRNormalizer/reordering.ll     | 109 +++++++++++++++++-
 1 file changed, 107 insertions(+), 2 deletions(-)

diff --git a/llvm/test/Transforms/IRNormalizer/reordering.ll b/llvm/test/Transforms/IRNormalizer/reordering.ll
index 1cca67427b533d..674c58ce3b2b80 100644
--- a/llvm/test/Transforms/IRNormalizer/reordering.ll
+++ b/llvm/test/Transforms/IRNormalizer/reordering.ll
@@ -1,5 +1,110 @@
-; RUN: opt -S -passes=normalize < %s | FileCheck %s
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -S -passes=normalize -verify-each < %s | FileCheck %s
 
 define void @foo() {
+; CHECK-LABEL: define void @foo() {
+; CHECK-NEXT:  bb17254:
+; CHECK-NEXT:    ret void
+;
   ret void
-}
\ No newline at end of file
+}
+
+define void @empty_basic_block() {
+; CHECK-LABEL: define void @empty_basic_block() {
+; CHECK-NEXT:  exit:
+; CHECK-NEXT:    ret void
+;
+exit:
+  ret void
+}
+
+declare void @effecting()
+
+; Place dead instruction(s) before the terminator
+define void @call_effecting() {
+; CHECK-LABEL: define void @call_effecting() {
+; CHECK-NEXT:  bb15160:
+; CHECK-NEXT:    call void @effecting()
+; CHECK-NEXT:    [[TMP0:%.*]] = add i32 0, 1
+; CHECK-NEXT:    ret void
+;
+  %1 = add i32 0, 1
+  call void @effecting()
+  ret void
+}
+
+define void @dont_move_above_phi() {
+; CHECK-LABEL: define void @dont_move_above_phi() {
+; CHECK-NEXT:  bb76951:
+; CHECK-NEXT:    br label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[TMP0:%.*]] = phi i32 [ 0, [[BB76951:%.*]] ]
+; CHECK-NEXT:    call void @effecting()
+; CHECK-NEXT:    ret void
+;
+  br label %exit
+exit:
+  %1 = phi i32 [0, %0]
+  call void @effecting()
+  ret void
+}
+
+define void @dont_move_above_alloca() {
+; CHECK-LABEL: define void @dont_move_above_alloca() {
+; CHECK-NEXT:  bb15160:
+; CHECK-NEXT:    [[TMP0:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @effecting()
+; CHECK-NEXT:    ret void
+;
+  %1 = alloca i32
+  call void @effecting()
+  ret void
+}
+
+declare void @effecting1()
+
+define void @dont_reorder_effecting() {
+; CHECK-LABEL: define void @dont_reorder_effecting() {
+; CHECK-NEXT:  bb10075:
+; CHECK-NEXT:    call void @effecting()
+; CHECK-NEXT:    call void @effecting1()
+; CHECK-NEXT:    ret void
+;
+  call void @effecting()
+  call void @effecting1()
+  ret void
+}
+
+declare void @effecting2(i32)
+
+define void @dont_reorder_effecting1() {
+; CHECK-LABEL: define void @dont_reorder_effecting1() {
+; CHECK-NEXT:  bb10075:
+; CHECK-NEXT:    [[ONE:%.*]] = add i32 1, 1
+; CHECK-NEXT:    call void @effecting2(i32 [[ONE]])
+; CHECK-NEXT:    [[TWO:%.*]] = add i32 2, 2
+; CHECK-NEXT:    call void @effecting2(i32 [[TWO]])
+; CHECK-NEXT:    ret void
+;
+  %one = add i32 1, 1
+  %two = add i32 2, 2
+  call void @effecting2(i32 %one)
+  call void @effecting2(i32 %two)
+  ret void
+}
+
+define void @dont_reorder_across_blocks() {
+; CHECK-LABEL: define void @dont_reorder_across_blocks() {
+; CHECK-NEXT:  bb76951:
+; CHECK-NEXT:    [[ONE:%.*]] = add i32 1, 1
+; CHECK-NEXT:    br label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    call void @effecting2(i32 [[ONE]])
+; CHECK-NEXT:    ret void
+;
+  %one = add i32 1, 1
+  br label %exit
+exit:
+  call void @effecting2(i32 %one)
+  ret void
+}



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