[llvm] llvm-canon (PR #68176)

Justin Fargnoli via llvm-commits llvm-commits at lists.llvm.org
Wed Oct 4 08:14:09 PDT 2023


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

>From f792a030ac1761a96176332fea906cd2d1826c7b Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 12 Aug 2023 10:58:45 -0700
Subject: [PATCH 01/16] 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 a870071f3f641dc..7866e7a8c09c3be 100644
--- a/llvm/lib/Transforms/Utils/CMakeLists.txt
+++ b/llvm/lib/Transforms/Utils/CMakeLists.txt
@@ -34,6 +34,7 @@ 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 000000000000000..58e2dce0b96685b
--- /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 d59bcfc2ccfd156e6ea152fc423feb213c169221 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 12 Aug 2023 15:55:40 -0700
Subject: [PATCH 02/16] Port IRCanonicalizer to new pass manager

---
 .../llvm/Transforms/Utils/IRCanonicalizer.h   | 15 +++++++++++++
 llvm/lib/Passes/PassBuilder.cpp               |  1 +
 llvm/lib/Passes/PassRegistry.def              |  1 +
 llvm/lib/Transforms/Utils/IRCanonicalizer.cpp | 22 +++++++++----------
 4 files changed, 27 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 000000000000000..81bfd1bcfd2ad94
--- /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 bb6b40b14f8b4c8..7b626f7df91cb39 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -237,6 +237,7 @@
 #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 fe24e9da9125ff7..fd30e5a8b4b58b8 100644
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -300,6 +300,7 @@ FUNCTION_PASS("bdce", BDCEPass())
 FUNCTION_PASS("bounds-checking", BoundsCheckingPass())
 FUNCTION_PASS("break-crit-edges", BreakCriticalEdgesPass())
 FUNCTION_PASS("callsite-splitting", CallSiteSplittingPass())
+FUNCTION_PASS("canon", IRCanonicalizerPass())
 FUNCTION_PASS("consthoist", ConstantHoistingPass())
 FUNCTION_PASS("count-visits", CountVisitsPass())
 FUNCTION_PASS("constraint-elimination", ConstraintEliminationPass())
diff --git a/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp b/llvm/lib/Transforms/Utils/IRCanonicalizer.cpp
index 58e2dce0b96685b..afa3d94e7f55be6 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 0c94ebab9a31092edfc409df6ffa922269fcf867 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 12 Aug 2023 16:06:29 -0700
Subject: [PATCH 03/16] Port doc updates

---
 llvm/docs/Passes.rst       | 8 ++++++++
 llvm/docs/ReleaseNotes.rst | 5 ++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/llvm/docs/Passes.rst b/llvm/docs/Passes.rst
index 541e23677debf90..418ab17eb35e259 100644
--- a/llvm/docs/Passes.rst
+++ b/llvm/docs/Passes.rst
@@ -653,6 +653,14 @@ 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
+--------------------------------------------------------
+
+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
 -----------------------------------
 
diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index 8eb8affb5eba9e2..dec2eec7566929e 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 9dbcab1948bba93e61d80a10038ab471f99e1448 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 12 Aug 2023 16:29:46 -0700
Subject: [PATCH 04/16] 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 000000000000000..b3f7630abd042f1
--- /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 000000000000000..79e526f8efb7ac7
--- /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 000000000000000..a22e816f5bf01e9
--- /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 000000000000000..04660ac73c11bd2
--- /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 000000000000000..5f344ec29be66f0
--- /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 f5b7445662310a2f329e0f4aaf45822058f307ba Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 19 Aug 2023 15:23:09 -0700
Subject: [PATCH 05/16] 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 afa3d94e7f55be6..b5a007c80b32b3f 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 b3f7630abd042f1..5a274f7cc5a3b70 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 04660ac73c11bd2..3ea19e8b6c78c97 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 5f344ec29be66f0..3ea0bab50b5b9ac 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 9f93dea7b9d1fb97f947481ac1211da11b897180 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sat, 19 Aug 2023 15:25:12 -0700
Subject: [PATCH 06/16] 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 000000000000000..f67c1eb7fa5b223
--- /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 23a379fc765a86c35b7b9682a66199fdaa1b830f Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sun, 27 Aug 2023 15:19:36 -0700
Subject: [PATCH 07/16] 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 b5a007c80b32b3f..73433a9a05c0d4e 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 560abe4f953f75a89e7a0407ff09ea866664a2fd Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Sun, 27 Aug 2023 15:20:12 -0700
Subject: [PATCH 08/16] 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 f67c1eb7fa5b223..3438a05b4aee489 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 3aaecbddf6a45ba23a32706ac99c8e6e963c924b 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 09/16] 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 73433a9a05c0d4e..600c2baf6e013a5 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 2111bf1e6a27c553990528abee3a9fa2c2390bdd 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 10/16] 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 000000000000000..74e1944825011b0
--- /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 1db7ecbc4a461295f7cdf04488b94984803a3e60 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Mon, 11 Sep 2023 12:27:35 -0700
Subject: [PATCH 11/16] 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 600c2baf6e013a5..6f60d3d261d8286 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 2debd15624fe9b69840551288bec734e8ef2ea75 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Mon, 11 Sep 2023 13:05:30 -0700
Subject: [PATCH 12/16] 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 6f60d3d261d8286..a40435f7b822932 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 8a05e501b94aa50a9802c4df5398dd5a0805572f Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Mon, 11 Sep 2023 13:29:27 -0700
Subject: [PATCH 13/16] 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 a40435f7b822932..45dc954f97b9c7e 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 5a274f7cc5a3b70..b3f7630abd042f1 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 3ea19e8b6c78c97..04660ac73c11bd2 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 3ea0bab50b5b9ac..5f344ec29be66f0 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 fa6159c30002c530f40b41380ed2b64294543c01 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Mon, 25 Sep 2023 11:13:25 -0500
Subject: [PATCH 14/16] 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 74e1944825011b0..605c62863f2ad38 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 aaef294128bb37afff42527cefbac08e29f08e95 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Tue, 3 Oct 2023 21:55:04 -0700
Subject: [PATCH 15/16] clang format changes

---
 llvm/lib/Passes/PassBuilder.cpp               |  4 ++--
 llvm/lib/Transforms/Utils/IRCanonicalizer.cpp | 12 ++++++------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index 8a495e6d7dc14fc..7fc17ab31a11ec8 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -233,14 +233,14 @@
 #include "llvm/Transforms/Utils/CanonicalizeAliases.h"
 #include "llvm/Transforms/Utils/CanonicalizeFreezeInLoops.h"
 #include "llvm/Transforms/Utils/CountVisits.h"
-#include "llvm/Transforms/Utils/Debugify.h"
 #include "llvm/Transforms/Utils/DXILUpgrade.h"
+#include "llvm/Transforms/Utils/Debugify.h"
 #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 45dc954f97b9c7e..7ea3959e5e90d00 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 d7b9fd5da45515624c6aa4b321d5d897612d2395 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Wed, 4 Oct 2023 08:12:40 -0700
Subject: [PATCH 16/16] 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 7ea3959e5e90d00..c12595ba48a3f79 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>
 



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