[llvm] Use DIExpression::foldConstantMath() at the result of an appendOpsToArg() (PR #71721)

Shubham Sandeep Rastogi via llvm-commits llvm-commits at lists.llvm.org
Fri Mar 8 17:58:03 PST 2024


https://github.com/rastogishubham updated https://github.com/llvm/llvm-project/pull/71721

>From d105b0f5e0da59a10f185bea88959ffb224e1601 Mon Sep 17 00:00:00 2001
From: Shubham Sandeep Rastogi <srastogi22 at apple.com>
Date: Wed, 4 Oct 2023 11:34:19 -0700
Subject: [PATCH 1/5] [NFC] Move DIExpressionCursor to DebugInfoMetadata.h

---
 llvm/include/llvm/IR/DebugInfoMetadata.h      | 61 +++++++++++++++++++
 llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h | 61 -------------------
 2 files changed, 61 insertions(+), 61 deletions(-)

diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
index 156f6eb49253de..28d2bc5faca580 100644
--- a/llvm/include/llvm/IR/DebugInfoMetadata.h
+++ b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -3093,6 +3093,67 @@ template <> struct DenseMapInfo<DIExpression::FragmentInfo> {
   static bool isEqual(const FragInfo &A, const FragInfo &B) { return A == B; }
 };
 
+/// Holds a DIExpression and keeps track of how many operands have been consumed
+/// so far.
+class DIExpressionCursor {
+  DIExpression::expr_op_iterator Start, End;
+
+public:
+  DIExpressionCursor(const DIExpression *Expr) {
+    if (!Expr) {
+      assert(Start == End);
+      return;
+    }
+    Start = Expr->expr_op_begin();
+    End = Expr->expr_op_end();
+  }
+
+  DIExpressionCursor(ArrayRef<uint64_t> Expr)
+      : Start(Expr.begin()), End(Expr.end()) {}
+
+  DIExpressionCursor(const DIExpressionCursor &) = default;
+
+  /// Consume one operation.
+  std::optional<DIExpression::ExprOperand> take() {
+    if (Start == End)
+      return std::nullopt;
+    return *(Start++);
+  }
+
+  /// Consume N operations.
+  void consume(unsigned N) { std::advance(Start, N); }
+
+  /// Return the current operation.
+  std::optional<DIExpression::ExprOperand> peek() const {
+    if (Start == End)
+      return std::nullopt;
+    return *(Start);
+  }
+
+  /// Return the next operation.
+  std::optional<DIExpression::ExprOperand> peekNext() const {
+    if (Start == End)
+      return std::nullopt;
+
+    auto Next = Start.getNext();
+    if (Next == End)
+      return std::nullopt;
+
+    return *Next;
+  }
+
+  /// Determine whether there are any operations left in this expression.
+  operator bool() const { return Start != End; }
+
+  DIExpression::expr_op_iterator begin() const { return Start; }
+  DIExpression::expr_op_iterator end() const { return End; }
+
+  /// Retrieve the fragment information, if any.
+  std::optional<DIExpression::FragmentInfo> getFragmentInfo() const {
+    return DIExpression::getFragmentInfo(Start, End);
+  }
+};
+
 /// Global variables.
 ///
 /// TODO: Remove DisplayName.  It's always equal to Name.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h
index 667a9efc6f6c04..4daa78b15b8e29 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.h
@@ -31,67 +31,6 @@ class DIELoc;
 class TargetRegisterInfo;
 class MachineLocation;
 
-/// Holds a DIExpression and keeps track of how many operands have been consumed
-/// so far.
-class DIExpressionCursor {
-  DIExpression::expr_op_iterator Start, End;
-
-public:
-  DIExpressionCursor(const DIExpression *Expr) {
-    if (!Expr) {
-      assert(Start == End);
-      return;
-    }
-    Start = Expr->expr_op_begin();
-    End = Expr->expr_op_end();
-  }
-
-  DIExpressionCursor(ArrayRef<uint64_t> Expr)
-      : Start(Expr.begin()), End(Expr.end()) {}
-
-  DIExpressionCursor(const DIExpressionCursor &) = default;
-
-  /// Consume one operation.
-  std::optional<DIExpression::ExprOperand> take() {
-    if (Start == End)
-      return std::nullopt;
-    return *(Start++);
-  }
-
-  /// Consume N operations.
-  void consume(unsigned N) { std::advance(Start, N); }
-
-  /// Return the current operation.
-  std::optional<DIExpression::ExprOperand> peek() const {
-    if (Start == End)
-      return std::nullopt;
-    return *(Start);
-  }
-
-  /// Return the next operation.
-  std::optional<DIExpression::ExprOperand> peekNext() const {
-    if (Start == End)
-      return std::nullopt;
-
-    auto Next = Start.getNext();
-    if (Next == End)
-      return std::nullopt;
-
-    return *Next;
-  }
-
-  /// Determine whether there are any operations left in this expression.
-  operator bool() const { return Start != End; }
-
-  DIExpression::expr_op_iterator begin() const { return Start; }
-  DIExpression::expr_op_iterator end() const { return End; }
-
-  /// Retrieve the fragment information, if any.
-  std::optional<DIExpression::FragmentInfo> getFragmentInfo() const {
-    return DIExpression::getFragmentInfo(Start, End);
-  }
-};
-
 /// Base class containing the logic for constructing DWARF expressions
 /// independently of whether they are emitted into a DIE or into a .debug_loc
 /// entry.

>From 1f9b4814ea4043bc7c7bd8cc2a8dd2c2c65319f5 Mon Sep 17 00:00:00 2001
From: Shubham Sandeep Rastogi <srastogi22 at apple.com>
Date: Wed, 1 Nov 2023 17:25:26 -0700
Subject: [PATCH 2/5] Add functions peekNextN(unsigned) and
 assignNewExpr(ArrayRef<uint64_t>) to DIExpressionCursor

This commit adds two functions to the DIExpressionCursor class.

peekNextN(unsigned) works like peekNext, but lets you peek the next Nth
element

assignNewExpr(ArrayRef<uint64_t>) lets you assign a new expression to
the same DIExpressionCursor object
---
 llvm/include/llvm/IR/DebugInfoMetadata.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
index 28d2bc5faca580..2450b46049ab51 100644
--- a/llvm/include/llvm/IR/DebugInfoMetadata.h
+++ b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -3142,6 +3142,23 @@ class DIExpressionCursor {
     return *Next;
   }
 
+  std::optional<DIExpression::ExprOperand> peekNextN(unsigned N) const {
+    if (Start == End)
+      return std::nullopt;
+    DIExpression::expr_op_iterator Nth = Start;
+    for (unsigned I = 0; I < N; I++) {
+      Nth = Nth.getNext();
+      if (Nth == End)
+        return std::nullopt;
+    }
+    return *Nth;
+  }
+
+  void assignNewExpr(ArrayRef<uint64_t> Expr) {
+    this->Start = DIExpression::expr_op_iterator(Expr.begin());
+    this->End = DIExpression::expr_op_iterator(Expr.end());
+  }
+
   /// Determine whether there are any operations left in this expression.
   operator bool() const { return Start != End; }
 

>From 766c3bc13f8688a4db76b055e93668f1f798724c Mon Sep 17 00:00:00 2001
From: Shubham Sandeep Rastogi <srastogi22 at apple.com>
Date: Fri, 20 Oct 2023 10:44:22 -0700
Subject: [PATCH 3/5] Introduce DIExpression::foldConstantMath()

DIExpressions can get very long and have a lot of redundant operations.
This function uses simple pattern matching to fold constant math that
can be evaluated at compile time.
---
 llvm/include/llvm/IR/DebugInfoMetadata.h |   5 +
 llvm/lib/IR/DebugInfoMetadata.cpp        | 316 ++++++++++++++++++++++-
 llvm/unittests/IR/MetadataTest.cpp       | 279 ++++++++++++++++++++
 3 files changed, 599 insertions(+), 1 deletion(-)

diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
index 2450b46049ab51..333a866fd3101e 100644
--- a/llvm/include/llvm/IR/DebugInfoMetadata.h
+++ b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -3064,6 +3064,11 @@ class DIExpression : public MDNode {
   /// expression and constant on failure.
   std::pair<DIExpression *, const ConstantInt *>
   constantFold(const ConstantInt *CI);
+
+  /// Try to shorten an expression with constant math operations that can be
+  /// evaulated at compile time. Returns a new expression on success, or the old
+  /// expression if there is nothing to be reduced.
+  DIExpression *foldConstantMath();
 };
 
 inline bool operator==(const DIExpression::FragmentInfo &A,
diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index 28f96653d815b5..550e47c9b8c024 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -1870,7 +1870,6 @@ DIExpression *DIExpression::append(const DIExpression *Expr,
     }
     Op.appendToVector(NewOps);
   }
-
   NewOps.append(Ops.begin(), Ops.end());
   auto *result = DIExpression::get(Expr->getContext(), NewOps);
   assert(result->isValid() && "concatenated expression is not valid");
@@ -2011,6 +2010,321 @@ DIExpression::constantFold(const ConstantInt *CI) {
           ConstantInt::get(getContext(), NewInt)};
 }
 
+static bool isConstantVal(uint64_t Op) {
+  return Op == dwarf::DW_OP_constu || Op == dwarf::DW_OP_consts;
+}
+
+static bool isNeutralElement(uint64_t Op, uint64_t Val) {
+  switch (Op) {
+  case dwarf::DW_OP_plus:
+  case dwarf::DW_OP_minus:
+  case dwarf::DW_OP_shl:
+  case dwarf::DW_OP_shr:
+    return Val == 0;
+  case dwarf::DW_OP_mul:
+  case dwarf::DW_OP_div:
+    return Val == 1;
+  default:
+    return false;
+  }
+}
+
+static std::optional<uint64_t>
+foldOperationIfPossible(uint64_t Op, uint64_t Operand1, uint64_t Operand2) {
+  switch (Op) {
+  case dwarf::DW_OP_plus:
+    return Operand1 + Operand2;
+  case dwarf::DW_OP_minus:
+    return Operand1 - Operand2;
+  case dwarf::DW_OP_shl:
+    return Operand1 << Operand2;
+  case dwarf::DW_OP_shr:
+    return Operand1 >> Operand2;
+  case dwarf::DW_OP_mul:
+    return Operand1 * Operand2;
+  case dwarf::DW_OP_div:
+    return Operand1 / Operand2;
+  default:
+    return std::nullopt;
+  }
+}
+
+static bool operationsAreFoldableAndCommutative(uint64_t Op1, uint64_t Op2) {
+  if (Op1 != Op2)
+    return false;
+  switch (Op1) {
+  case dwarf::DW_OP_plus:
+  case dwarf::DW_OP_mul:
+    return true;
+  default:
+    return false;
+  }
+}
+
+static void consumeOneOperator(DIExpressionCursor &Cursor, uint64_t &Loc,
+                               const DIExpression::ExprOperand &Op) {
+  Cursor.consume(1);
+  Loc = Loc + Op.getSize();
+}
+
+static void startFromBeginning(uint64_t &Loc, DIExpressionCursor &Cursor,
+                               ArrayRef<uint64_t> WorkingOps) {
+  Cursor.assignNewExpr(WorkingOps);
+  Loc = 0;
+}
+
+static void moveCursorToCurrentOp(uint64_t &Loc, DIExpressionCursor &Cursor,
+                                  ArrayRef<uint64_t> WorkingOps,
+                                  uint32_t NumOfOpsConsumed) {
+  Cursor.assignNewExpr(WorkingOps);
+  Cursor.consume(NumOfOpsConsumed);
+  assert(Cursor.peek()->getOp() == WorkingOps[Loc] &&
+         "Cursor position does not match position of iterator 'Loc' to "
+         "WorkingOps");
+}
+
+// This function will canonicalize:
+// 1. DW_OP_plus_uconst to DW_OP_constu <const-val> DW_OP_plus
+// 2. DW_OP_lit<n> to DW_OP_constu <n>
+static void canonicalizeDwarfOperations(SmallVectorImpl<uint64_t> &WorkingOps) {
+  DIExpressionCursor Cursor(WorkingOps);
+  uint64_t Loc = 0;
+  uint32_t NumOfOpsConsumed = 0;
+  while (Loc < WorkingOps.size()) {
+    auto Op = Cursor.peek();
+    // Expression has no operations, break.
+    if (!Op)
+      break;
+    auto OpRaw = Op->getOp();
+    auto OpArg = Op->getArg(0);
+
+    if (OpRaw >= dwarf::DW_OP_lit0 && OpRaw <= dwarf::DW_OP_lit31) {
+      WorkingOps[Loc] = dwarf::DW_OP_constu;
+      WorkingOps.insert(WorkingOps.begin() + Loc + 1,
+                        OpRaw - dwarf::DW_OP_lit0);
+    } else if (OpRaw == dwarf::DW_OP_plus_uconst) {
+      WorkingOps[Loc] = dwarf::DW_OP_constu;
+      WorkingOps[Loc + 1] = OpArg;
+      WorkingOps.insert(WorkingOps.begin() + Loc + 2, dwarf::DW_OP_plus);
+      moveCursorToCurrentOp(Loc, Cursor, WorkingOps, NumOfOpsConsumed);
+    }
+    consumeOneOperator(Cursor, Loc, *Cursor.peek());
+    NumOfOpsConsumed++;
+  }
+}
+
+// This function will convert:
+// DW_OP_constu <const-val> DW_OP_plus to DW_OP_plus_uconst
+static void optimizeDwarfOperations(SmallVectorImpl<uint64_t> &WorkingOps) {
+  DIExpressionCursor Cursor(WorkingOps);
+  uint64_t Loc = 0;
+  uint32_t NumOfOpsConsumed = 0;
+  while (Loc < WorkingOps.size()) {
+    auto Op1 = Cursor.peek();
+    // Expression has no operations, exit.
+    if (!Op1)
+      break;
+    auto Op1Raw = Op1->getOp();
+    auto Op1Arg = Op1->getArg(0);
+
+    if (Op1Raw == dwarf::DW_OP_constu && Op1Arg == 0) {
+      WorkingOps[Loc] = dwarf::DW_OP_lit0;
+      WorkingOps.erase(WorkingOps.begin() + Loc + 1);
+      moveCursorToCurrentOp(Loc, Cursor, WorkingOps, NumOfOpsConsumed);
+      continue;
+    }
+
+    auto Op2 = Cursor.peekNext();
+    // Expression has no more operations, exit.
+    if (!Op2)
+      break;
+    auto Op2Raw = Op2->getOp();
+
+    if (Op1Raw == dwarf::DW_OP_constu && Op2Raw == dwarf::DW_OP_plus) {
+      WorkingOps.erase(WorkingOps.begin() + Loc + 2);
+      WorkingOps[Loc] = dwarf::DW_OP_plus_uconst;
+      WorkingOps[Loc + 1] = Op1Arg;
+      moveCursorToCurrentOp(Loc, Cursor, WorkingOps, NumOfOpsConsumed);
+    }
+    consumeOneOperator(Cursor, Loc, *Cursor.peek());
+    NumOfOpsConsumed++;
+  }
+}
+
+// {DW_OP_const[u, s], 0, DW_OP_[plus, minus, shl, shr]} -> {}
+// {DW_OP_const[u, s], 1, DW_OP_[mul, div]} -> {}
+static bool tryFoldNoOpMath(uint64_t Op1Raw, uint64_t Op1Arg, uint64_t Op2Raw,
+                            uint64_t &Loc, DIExpressionCursor &Cursor,
+                            SmallVectorImpl<uint64_t> &WorkingOps) {
+  if (isConstantVal(Op1Raw) && isNeutralElement(Op2Raw, Op1Arg)) {
+    WorkingOps.erase(WorkingOps.begin() + Loc, WorkingOps.begin() + Loc + 3);
+    startFromBeginning(Loc, Cursor, WorkingOps);
+    return true;
+  }
+  return false;
+}
+
+// {DW_OP_const[u, s], Const1, DW_OP_const[u, s], Const2, DW_OP_[plus,
+// minus, mul, div, shl, shr] -> {DW_OP_constu, Const1 [+, -, *, /, <<, >>]
+// Const2}
+static bool tryFoldConstants(std::optional<DIExpression::ExprOperand> Op1,
+                             uint64_t Op1Raw, uint64_t Op1Arg, uint64_t Op2Raw,
+                             uint64_t Op2Arg, uint64_t Op3Raw, uint64_t &Loc,
+                             DIExpressionCursor &Cursor,
+                             SmallVectorImpl<uint64_t> &WorkingOps) {
+  if (isConstantVal(Op1Raw) && isConstantVal(Op2Raw)) {
+    auto Result = foldOperationIfPossible(Op3Raw, Op1Arg, Op2Arg);
+    if (!Result) {
+      consumeOneOperator(Cursor, Loc, *Op1);
+      return true;
+    }
+    WorkingOps.erase(WorkingOps.begin() + Loc + 2,
+                     WorkingOps.begin() + Loc + 5);
+    WorkingOps[Loc] = dwarf::DW_OP_constu;
+    WorkingOps[Loc + 1] = *Result;
+    startFromBeginning(Loc, Cursor, WorkingOps);
+    return true;
+  }
+  return false;
+}
+
+// {DW_OP_const[u, s], Const1, DW_OP_[plus, mul], DW_OP_const[u, s], Const2,
+// DW_OP_[plus, mul]} -> {DW_OP_constu, Const1 [+, *] Const2, DW_OP_[plus, mul]}
+static bool tryFoldCommutativeMath(uint64_t Op1Raw, uint64_t Op1Arg,
+                                   uint64_t Op2Raw, uint64_t Op2Arg,
+                                   uint64_t Op3Raw, uint64_t Op3Arg,
+                                   uint64_t Op4Raw, uint64_t &Loc,
+                                   DIExpressionCursor &Cursor,
+                                   SmallVectorImpl<uint64_t> &WorkingOps) {
+
+  if (isConstantVal(Op1Raw) && isConstantVal(Op3Raw) &&
+      operationsAreFoldableAndCommutative(Op2Raw, Op4Raw)) {
+    auto Result = foldOperationIfPossible(Op2Raw, Op1Arg, Op3Arg);
+    if (!Result)
+      llvm_unreachable(
+          "Something went very wrong here! This should always work");
+    WorkingOps.erase(WorkingOps.begin() + Loc + 3,
+                     WorkingOps.begin() + Loc + 6);
+    WorkingOps[Loc] = dwarf::DW_OP_constu;
+    WorkingOps[Loc + 1] = *Result;
+    startFromBeginning(Loc, Cursor, WorkingOps);
+    return true;
+  }
+  return false;
+}
+
+// {DW_OP_const[u, s], Const1, DW_OP_[plus, mul], DW_OP_LLVM_arg, Arg1,
+// DW_OP_[plus, mul], DW_OP_const[u, s], Const2, DW_OP_[plus, mul]} ->
+// {DW_OP_constu, Const1 [+, *] Const2, DW_OP_[plus, mul], DW_OP_LLVM_arg,
+// Arg1, DW_OP_[plus, mul]}
+static bool tryFoldCommutativeMathWithArgInBetween(
+    uint64_t Op1Raw, uint64_t Op1Arg, uint64_t Op2Raw, uint64_t Op3Raw,
+    uint64_t Op4Raw, uint64_t Op5Raw, uint64_t Op5Arg, uint64_t Op6Raw,
+    uint64_t &Loc, DIExpressionCursor &Cursor,
+    SmallVectorImpl<uint64_t> &WorkingOps) {
+  if (isConstantVal(Op1Raw) && Op3Raw == dwarf::DW_OP_LLVM_arg &&
+      isConstantVal(Op5Raw) &&
+      operationsAreFoldableAndCommutative(Op2Raw, Op4Raw) &&
+      operationsAreFoldableAndCommutative(Op4Raw, Op6Raw)) {
+    auto Result = foldOperationIfPossible(Op2Raw, Op1Arg, Op5Arg);
+    if (!Result)
+      llvm_unreachable(
+          "Something went very wrong here! This should always work");
+    WorkingOps.erase(WorkingOps.begin() + Loc + 6,
+                     WorkingOps.begin() + Loc + 9);
+    WorkingOps[Loc] = dwarf::DW_OP_constu;
+    WorkingOps[Loc + 1] = *Result;
+    startFromBeginning(Loc, Cursor, WorkingOps);
+    return true;
+  }
+  return false;
+}
+
+DIExpression *DIExpression::foldConstantMath() {
+
+  SmallVector<uint64_t, 8> WorkingOps(Elements.begin(), Elements.end());
+  uint64_t Loc = 0;
+  canonicalizeDwarfOperations(WorkingOps);
+  DIExpressionCursor Cursor(WorkingOps);
+
+  while (Loc < WorkingOps.size()) {
+
+    auto Op1 = Cursor.peek();
+    // Expression has no operations, exit.
+    if (!Op1)
+      break;
+    auto Op1Raw = Op1->getOp();
+    auto Op1Arg = Op1->getArg(0);
+
+    if (!isConstantVal(Op1Raw)) {
+      // Early exit, all of the following patterns start with a constant value.
+      consumeOneOperator(Cursor, Loc, *Op1);
+      continue;
+    }
+
+    auto Op2 = Cursor.peekNext();
+    // All following patterns require at least 2 Operations, exit.
+    if (!Op2)
+      break;
+    auto Op2Raw = Op2->getOp();
+
+    if (tryFoldNoOpMath(Op1Raw, Op1Arg, Op2Raw, Loc, Cursor, WorkingOps))
+      continue;
+
+    auto Op2Arg = Op2->getArg(0);
+
+    auto Op3 = Cursor.peekNextN(2);
+    // Op2 could still match a pattern, skip iteration.
+    if (!Op3) {
+      consumeOneOperator(Cursor, Loc, *Op1);
+      continue;
+    }
+    auto Op3Raw = Op3->getOp();
+
+    if (tryFoldConstants(Op1, Op1Raw, Op1Arg, Op2Raw, Op2Arg, Op3Raw, Loc,
+                         Cursor, WorkingOps))
+      continue;
+
+    auto Op3Arg = Op3->getArg(0);
+
+    auto Op4 = Cursor.peekNextN(3);
+    // Op2 and Op3 could still match a pattern, skip iteration.
+    if (!Op4) {
+      consumeOneOperator(Cursor, Loc, *Op1);
+      continue;
+    }
+    auto Op4Raw = Op4->getOp();
+
+    if (tryFoldCommutativeMath(Op1Raw, Op1Arg, Op2Raw, Op2Arg, Op3Raw, Op3Arg,
+                               Op4Raw, Loc, Cursor, WorkingOps))
+      continue;
+
+    auto Op5 = Cursor.peekNextN(4);
+    if (!Op5) {
+      consumeOneOperator(Cursor, Loc, *Op1);
+      continue;
+    }
+    auto Op5Raw = Op5->getOp();
+    auto Op5Arg = Op5->getArg(0);
+    auto Op6 = Cursor.peekNextN(5);
+    if (!Op6) {
+      consumeOneOperator(Cursor, Loc, *Op1);
+      continue;
+    }
+    auto Op6Raw = Op6->getOp();
+    if (tryFoldCommutativeMathWithArgInBetween(Op1Raw, Op1Arg, Op2Raw, Op3Raw,
+                                               Op4Raw, Op5Raw, Op5Arg, Op6Raw,
+                                               Loc, Cursor, WorkingOps))
+      continue;
+
+    consumeOneOperator(Cursor, Loc, *Op1);
+  }
+  optimizeDwarfOperations(WorkingOps);
+  auto *Result = DIExpression::get(getContext(), WorkingOps);
+  assert(Result->isValid() && "concatenated expression is not valid");
+  return Result;
+}
+
 uint64_t DIExpression::getNumLocationOperands() const {
   uint64_t Result = 0;
   for (auto ExprOp : expr_ops())
diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
index 767dd1a59d2b9e..c6c9b2a683f9e9 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -3120,6 +3120,285 @@ TEST_F(DIExpressionTest, get) {
   EXPECT_EQ(N0WithPrependedOps, N2);
 }
 
+TEST_F(DIExpressionTest, Fold) {
+
+  // Remove a No-op DW_OP_plus_uconst from an expression.
+  SmallVector<uint64_t, 8> Ops = {dwarf::DW_OP_plus_uconst, 0};
+  auto *Expr = DIExpression::get(Context, Ops);
+  auto *E = Expr->foldConstantMath();
+  SmallVector<uint64_t, 8> ResOps;
+  auto *ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Remove a No-op add from an expression.
+  Ops[0] = dwarf::DW_OP_constu;
+  Ops[1] = 0;
+  Ops.push_back(dwarf::DW_OP_plus);
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Remove a No-op subtract from an expression.
+  Ops[2] = dwarf::DW_OP_minus;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Remove a No-op shift left from an expression.
+  Ops[2] = dwarf::DW_OP_shl;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Remove a No-op shift right from an expression.
+  Ops[2] = dwarf::DW_OP_shr;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Remove a No-op multiply from an expression.
+  Ops[2] = dwarf::DW_OP_mul;
+  Ops[1] = 1;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Remove a No-op divide from an expression.
+  Ops[2] = dwarf::DW_OP_div;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test fold {DW_OP_plus_uconst, Const1, DW_OP_plus_uconst, Const2} ->
+  // {DW_OP_plus_uconst, Const1 + Const2}
+  Ops[0] = dwarf::DW_OP_plus_uconst;
+  Ops[1] = 2;
+  Ops[2] = dwarf::DW_OP_plus_uconst;
+  Ops.push_back(3);
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps.push_back(dwarf::DW_OP_plus_uconst);
+  ResOps.push_back(5);
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_constu, Const1, DW_OP_plus_uconst, Const2} -> {DW_OP_constu,
+  // Const1 + Const2}
+  Ops[0] = dwarf::DW_OP_constu;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps[0] = dwarf::DW_OP_constu;
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_plus} ->
+  // {DW_OP_constu, Const1 + Const2}
+  Ops[1] = 8;
+  Ops[2] = dwarf::DW_OP_constu;
+  Ops[3] = 2;
+  Ops.push_back(dwarf::DW_OP_plus);
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps[0] = dwarf::DW_OP_constu;
+  ResOps[1] = 10;
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_minus} ->
+  // {DW_OP_constu, Const1 - Const2}
+  Ops[4] = dwarf::DW_OP_minus;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps[0] = dwarf::DW_OP_constu;
+  ResOps[1] = 6;
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_mul} ->
+  // {DW_OP_constu, Const1 * Const2}
+  Ops[4] = dwarf::DW_OP_mul;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps[0] = dwarf::DW_OP_constu;
+  ResOps[1] = 16;
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_div} ->
+  // {DW_OP_constu, Const1 / Const2}
+  Ops[4] = dwarf::DW_OP_div;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps[0] = dwarf::DW_OP_constu;
+  ResOps[1] = 4;
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_shl} ->
+  // {DW_OP_constu, Const1 << Const2}
+  Ops[4] = dwarf::DW_OP_shl;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps[0] = dwarf::DW_OP_constu;
+  ResOps[1] = 32;
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_shr} ->
+  // {DW_OP_constu, Const1 >> Const2}
+  Ops[4] = dwarf::DW_OP_shr;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps[0] = dwarf::DW_OP_constu;
+  ResOps[1] = 2;
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_plus_uconst, Const1, DW_OP_constu, Const2, DW_OP_plus} ->
+  // {DW_OP_plus_uconst, Const1 + Const2}
+  Ops[0] = dwarf::DW_OP_plus_uconst;
+  Ops[1] = 8;
+  Ops[2] = dwarf::DW_OP_constu;
+  Ops[3] = 2;
+  Ops[4] = dwarf::DW_OP_plus;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps[0] = dwarf::DW_OP_plus_uconst;
+  ResOps[1] = 10;
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_constu, Const1, DW_OP_plus, DW_OP_plus_uconst, Const2} ->
+  // {DW_OP_plus_uconst, Const1 + Const2}
+  Ops[0] = dwarf::DW_OP_constu;
+  Ops[1] = 8;
+  Ops[2] = dwarf::DW_OP_plus;
+  Ops[3] = dwarf::DW_OP_plus_uconst;
+  Ops[4] = 2;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_constu, Const1, DW_OP_plus, DW_OP_constu, Const2, DW_OP_plus}
+  // -> {DW_OP_plus_uconst, Const1 + Const2}
+  Ops[0] = dwarf::DW_OP_constu;
+  Ops[1] = 8;
+  Ops[2] = dwarf::DW_OP_plus;
+  Ops[3] = dwarf::DW_OP_constu;
+  Ops[4] = 2;
+  Ops.push_back(dwarf::DW_OP_plus);
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps[0] = dwarf::DW_OP_plus_uconst;
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_constu, Const1, DW_OP_mul, DW_OP_constu, Const2, DW_OP_mul} ->
+  // {DW_OP_constu, Const1 * Const2, DW_OP_mul}
+  Ops[0] = dwarf::DW_OP_constu;
+  Ops[1] = 8;
+  Ops[2] = dwarf::DW_OP_mul;
+  Ops[3] = dwarf::DW_OP_constu;
+  Ops[4] = 2;
+  Ops[5] = dwarf::DW_OP_mul;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps[0] = dwarf::DW_OP_constu;
+  ResOps[1] = 16;
+  ResOps.push_back(dwarf::DW_OP_mul);
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_plus_uconst, Const1, DW_OP_plus, DW_OP_LLVM_arg, Arg,
+  // DW_OP_plus, DW_OP_constu, Const2, DW_OP_plus} -> {DW_OP_plus_uconst, Const1
+  // + Const2, DW_OP_LLVM_arg, Arg, DW_OP_plus}
+  Ops[0] = dwarf::DW_OP_plus_uconst;
+  Ops[1] = 8;
+  Ops[2] = dwarf::DW_OP_LLVM_arg;
+  Ops[3] = 0;
+  Ops[4] = dwarf::DW_OP_plus;
+  Ops[5] = dwarf::DW_OP_constu;
+  Ops.push_back(2);
+  Ops.push_back(dwarf::DW_OP_plus);
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps[0] = dwarf::DW_OP_plus_uconst;
+  ResOps[1] = 10;
+  ResOps[2] = dwarf::DW_OP_LLVM_arg;
+  ResOps.push_back(0);
+  ResOps.push_back(dwarf::DW_OP_plus);
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_constu, Const1, DW_OP_plus, DW_OP_LLVM_arg, Arg, DW_OP_plus,
+  // DW_OP_plus_uconst, Const2} -> {DW_OP_constu, Const1 + Const2, DW_OP_plus,
+  // DW_OP_LLVM_arg, Arg, DW_OP_plus}
+  Ops[0] = dwarf::DW_OP_constu;
+  Ops[1] = 8;
+  Ops[2] = dwarf::DW_OP_plus;
+  Ops[3] = dwarf::DW_OP_LLVM_arg;
+  Ops[4] = 0;
+  Ops[5] = dwarf::DW_OP_plus;
+  Ops[6] = dwarf::DW_OP_plus_uconst;
+  Ops[7] = 2;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps[0] = dwarf::DW_OP_plus_uconst;
+  ResOps[1] = 10;
+  ResOps[2] = dwarf::DW_OP_LLVM_arg;
+  ResOps[3] = 0;
+  ResOps[4] = dwarf::DW_OP_plus;
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_constu, Const1, DW_OP_plus, DW_OP_LLVM_arg, Arg, DW_OP_plus,
+  // DW_OP_constu, Const2, DW_OP_plus} -> {DW_OP_constu, Const1 + Const2,
+  // DW_OP_plus, DW_OP_LLVM_arg, Arg, DW_OP_plus}
+  Ops[0] = dwarf::DW_OP_constu;
+  Ops[1] = 8;
+  Ops[2] = dwarf::DW_OP_plus;
+  Ops[3] = dwarf::DW_OP_LLVM_arg;
+  Ops[4] = 0;
+  Ops[5] = dwarf::DW_OP_plus;
+  Ops[6] = dwarf::DW_OP_constu;
+  Ops[7] = 2;
+  Ops.push_back(dwarf::DW_OP_plus);
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+
+  // Test {DW_OP_constu, Const1, DW_OP_mul, DW_OP_LLVM_arg, Arg, DW_OP_mul,
+  // DW_OP_constu, Const2, DW_OP_mul} -> {DW_OP_constu, Const1 * Const2,
+  // DW_OP_mul, DW_OP_LLVM_arg, Arg, DW_OP_mul}
+  Ops[0] = dwarf::DW_OP_constu;
+  Ops[1] = 8;
+  Ops[2] = dwarf::DW_OP_mul;
+  Ops[3] = dwarf::DW_OP_LLVM_arg;
+  Ops[4] = 0;
+  Ops[5] = dwarf::DW_OP_mul;
+  Ops[6] = dwarf::DW_OP_constu;
+  Ops[7] = 2;
+  Ops[8] = dwarf::DW_OP_mul;
+  Expr = DIExpression::get(Context, Ops);
+  E = Expr->foldConstantMath();
+  ResOps[0] = dwarf::DW_OP_constu;
+  ResOps[1] = 16;
+  ResOps[2] = dwarf::DW_OP_mul;
+  ResOps[3] = dwarf::DW_OP_LLVM_arg;
+  ResOps[4] = 0;
+  ResOps.push_back(dwarf::DW_OP_mul);
+  ResExpr = DIExpression::get(Context, ResOps);
+  EXPECT_EQ(E, ResExpr);
+}
+
 TEST_F(DIExpressionTest, isValid) {
 #define EXPECT_VALID(...)                                                      \
   do {                                                                         \

>From 29b0eee0254bf8d14c9b726163343af165bfca34 Mon Sep 17 00:00:00 2001
From: Shubham Sandeep Rastogi <srastogi22 at apple.com>
Date: Fri, 8 Mar 2024 11:28:34 -0800
Subject: [PATCH 4/5] Use DIExpression:foldConstantMath() at the result of an
 append()

---
 llvm/lib/IR/DebugInfoMetadata.cpp             |  3 +-
 llvm/test/Bitcode/upgrade-dbg-addr.ll         |  2 +-
 .../MIR/AArch64/dbgcall-site-expr-chain.mir   |  4 +-
 llvm/unittests/IR/MetadataTest.cpp            | 88 +++++++++++++++++++
 4 files changed, 93 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index 550e47c9b8c024..92b5ce01f6db0a 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -1871,7 +1871,8 @@ DIExpression *DIExpression::append(const DIExpression *Expr,
     Op.appendToVector(NewOps);
   }
   NewOps.append(Ops.begin(), Ops.end());
-  auto *result = DIExpression::get(Expr->getContext(), NewOps);
+  auto *result =
+      DIExpression::get(Expr->getContext(), NewOps)->foldConstantMath();
   assert(result->isValid() && "concatenated expression is not valid");
   return result;
 }
diff --git a/llvm/test/Bitcode/upgrade-dbg-addr.ll b/llvm/test/Bitcode/upgrade-dbg-addr.ll
index 40fd7db18948b5..1943c35b0059fb 100644
--- a/llvm/test/Bitcode/upgrade-dbg-addr.ll
+++ b/llvm/test/Bitcode/upgrade-dbg-addr.ll
@@ -8,7 +8,7 @@ entry:
   %num.addr = alloca i32, align 4
   store i32 %num, ptr %num.addr, align 4
   ; CHECK-NOT: call void @llvm.dbg.addr
-  ; CHECK: call void @llvm.dbg.value(metadata ptr %num.addr, metadata ![[#]], metadata !DIExpression(DW_OP_plus_uconst, 0, DW_OP_deref))
+  ; CHECK: call void @llvm.dbg.value(metadata ptr %num.addr, metadata ![[#]], metadata !DIExpression(DW_OP_deref))
   call void @llvm.dbg.addr(metadata ptr %num.addr, metadata !16, metadata !DIExpression(DW_OP_plus_uconst, 0)), !dbg !17
   %0 = load i32, ptr %num.addr, align 4
   ret i32 %0
diff --git a/llvm/test/DebugInfo/MIR/AArch64/dbgcall-site-expr-chain.mir b/llvm/test/DebugInfo/MIR/AArch64/dbgcall-site-expr-chain.mir
index cb3e780664404c..02f4ce1200ca17 100644
--- a/llvm/test/DebugInfo/MIR/AArch64/dbgcall-site-expr-chain.mir
+++ b/llvm/test/DebugInfo/MIR/AArch64/dbgcall-site-expr-chain.mir
@@ -105,7 +105,7 @@ body:             |
 
 # CHECK: DW_TAG_GNU_call_site_parameter
 # CHECK-NEXT: DW_AT_location (DW_OP_reg2 W2)
-# CHECK-NEXT: DW_AT_GNU_call_site_value (DW_OP_breg19 W19+700, DW_OP_plus_uconst 0x9, DW_OP_plus_uconst 0x50)
+# CHECK-NEXT: DW_AT_GNU_call_site_value (DW_OP_breg19 W19+789)
 
 # CHECK: DW_TAG_GNU_call_site_parameter
 # CHECK-NEXT: DW_AT_location (DW_OP_reg1 W1)
@@ -113,4 +113,4 @@ body:             |
 
 # CHECK: DW_TAG_GNU_call_site_parameter
 # CHECK-NEXT: DW_AT_location (DW_OP_reg0 W0)
-# CHECK-NEXT: DW_AT_GNU_call_site_value (DW_OP_breg19 W19+100, DW_OP_plus_uconst 0x17)
+# CHECK-NEXT: DW_AT_GNU_call_site_value (DW_OP_breg19 W19+123)
diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
index c6c9b2a683f9e9..8368b83a6d4684 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -3399,6 +3399,94 @@ TEST_F(DIExpressionTest, Fold) {
   EXPECT_EQ(E, ResExpr);
 }
 
+TEST_F(DIExpressionTest, Append) {
+  // Test appending a {dwarf::DW_OP_constu, <const>, DW_OP_plus} to a DW_OP_plus
+  // expression
+  SmallVector<uint64_t, 8> Ops = {dwarf::DW_OP_LLVM_arg, 0, dwarf::DW_OP_constu,
+                                  2, dwarf::DW_OP_plus};
+  auto *Expr = DIExpression::get(Context, Ops);
+  SmallVector<uint64_t, 8> AppendOps = {dwarf::DW_OP_constu, 3,
+                                        dwarf::DW_OP_plus};
+  auto *AppendExpr = DIExpression::append(Expr, AppendOps);
+  SmallVector<uint64_t, 8> OpsRes = {dwarf::DW_OP_LLVM_arg, 0,
+                                     dwarf::DW_OP_plus_uconst, 5};
+  auto *ResExpr = DIExpression::get(Context, OpsRes);
+  EXPECT_EQ(ResExpr, AppendExpr);
+
+  // Test appending a {dwarf::DW_OP_plus_uconst, <const>} to a DW_OP_plus
+  // expression uint64_t PlusUConstOps[] = {dwarf::DW_OP_plus_uconst, 3};
+  AppendOps.clear();
+  AppendOps.push_back(dwarf::DW_OP_plus_uconst);
+  AppendOps.push_back(3);
+  AppendExpr = DIExpression::append(Expr, AppendOps);
+  OpsRes.clear();
+  OpsRes.push_back(dwarf::DW_OP_LLVM_arg);
+  OpsRes.push_back(0);
+  OpsRes.push_back(dwarf::DW_OP_plus_uconst);
+  OpsRes.push_back(5);
+  ResExpr = DIExpression::get(Context, OpsRes);
+  EXPECT_EQ(ResExpr, AppendExpr);
+
+  // Test appending a {dwarf::DW_OP_constu, 0, DW_OP_plus} to an expression
+  AppendOps[0] = dwarf::DW_OP_constu;
+  AppendOps[1] = 0;
+  AppendOps.push_back(dwarf::DW_OP_plus);
+  AppendExpr = DIExpression::append(Expr, AppendOps);
+  OpsRes[2] = dwarf::DW_OP_plus_uconst;
+  OpsRes[3] = Ops[3];
+  ResExpr = DIExpression::get(Context, OpsRes);
+  EXPECT_EQ(ResExpr, AppendExpr);
+
+  // Test appending a {dwarf::DW_OP_constu, 0, DW_OP_minus} to an expression
+  AppendOps[2] = dwarf::DW_OP_minus;
+  AppendExpr = DIExpression::append(Expr, AppendOps);
+  OpsRes[3] = Ops[3];
+  ResExpr = DIExpression::get(Context, OpsRes);
+  EXPECT_EQ(ResExpr, AppendExpr);
+
+  // Test appending a {dwarf::DW_OP_constu, 0, DW_OP_shl} to an expression
+  AppendOps[2] = dwarf::DW_OP_shl;
+  AppendExpr = DIExpression::append(Expr, AppendOps);
+  OpsRes[3] = Ops[3];
+  ResExpr = DIExpression::get(Context, OpsRes);
+  EXPECT_EQ(ResExpr, AppendExpr);
+
+  // Test appending a {dwarf::DW_OP_constu, 0, DW_OP_shr} to an expression
+  AppendOps[2] = dwarf::DW_OP_shr;
+  AppendExpr = DIExpression::append(Expr, AppendOps);
+  OpsRes[3] = Ops[3];
+  ResExpr = DIExpression::get(Context, OpsRes);
+  EXPECT_EQ(ResExpr, AppendExpr);
+
+  // Test appending a {dwarf::DW_OP_constu, <const>, DW_OP_mul} to a DW_OP_mul
+  // expression
+  Ops[4] = dwarf::DW_OP_mul;
+  Expr = DIExpression::get(Context, Ops);
+  AppendOps[1] = 3;
+  AppendOps[2] = dwarf::DW_OP_mul;
+  AppendExpr = DIExpression::append(Expr, AppendOps);
+  OpsRes[2] = dwarf::DW_OP_constu;
+  OpsRes[3] = 6;
+  OpsRes.push_back(dwarf::DW_OP_mul);
+  ResExpr = DIExpression::get(Context, OpsRes);
+  EXPECT_EQ(ResExpr, AppendExpr);
+
+  // Test appending a {dwarf::DW_OP_constu, 1, DW_OP_mul} to an expression
+  AppendOps[1] = 1;
+  AppendExpr = DIExpression::append(Expr, AppendOps);
+  OpsRes[3] = Ops[3];
+  ResExpr = DIExpression::get(Context, OpsRes);
+  EXPECT_EQ(ResExpr, AppendExpr);
+
+  // Test appending a {dwarf::DW_OP_constu, 1, DW_OP_div} to an expression
+  AppendOps[1] = 1;
+  AppendOps[2] = dwarf::DW_OP_div;
+  AppendExpr = DIExpression::append(Expr, AppendOps);
+  OpsRes[3] = Ops[3];
+  ResExpr = DIExpression::get(Context, OpsRes);
+  EXPECT_EQ(ResExpr, AppendExpr);
+}
+
 TEST_F(DIExpressionTest, isValid) {
 #define EXPECT_VALID(...)                                                      \
   do {                                                                         \

>From 629c305d937e7dfd0228815d5180bb2b62b4d99b Mon Sep 17 00:00:00 2001
From: Shubham Sandeep Rastogi <srastogi22 at apple.com>
Date: Fri, 8 Mar 2024 17:47:17 -0800
Subject: [PATCH 5/5] Use DIExpression:foldConstantMath() at the result of an
 appendOpsToArg()

---
 llvm/lib/IR/DebugInfoMetadata.cpp             |  5 +-
 .../MIR/InstrRef/deref-spills-with-size.mir   | 24 +++----
 .../InstrRef/follow-spill-of-indir-value.mir  |  4 +-
 llvm/test/DebugInfo/salvage-icmp.ll           |  2 +-
 .../Transforms/Coroutines/swift-async-dbg.ll  |  8 +--
 .../Transforms/InstCombine/cast-mul-select.ll |  2 +-
 .../Transforms/InstCombine/debuginfo-dce.ll   |  2 +-
 .../Transforms/InstCombine/debuginfo-sink.ll  | 62 +++++++++----------
 llvm/unittests/IR/MetadataTest.cpp            | 19 ++++++
 llvm/unittests/Transforms/Utils/LocalTest.cpp |  3 +-
 10 files changed, 75 insertions(+), 56 deletions(-)

diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index 92b5ce01f6db0a..5abced5a191ef7 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -1774,7 +1774,8 @@ DIExpression *DIExpression::appendOpsToArg(const DIExpression *Expr,
     assert(ArgNo == 0 &&
            "Location Index must be 0 for a non-variadic expression.");
     SmallVector<uint64_t, 8> NewOps(Ops.begin(), Ops.end());
-    return DIExpression::prependOpcodes(Expr, NewOps, StackValue);
+    return DIExpression::prependOpcodes(Expr, NewOps, StackValue)
+        ->foldConstantMath();
   }
 
   SmallVector<uint64_t, 8> NewOps;
@@ -1795,7 +1796,7 @@ DIExpression *DIExpression::appendOpsToArg(const DIExpression *Expr,
   if (StackValue)
     NewOps.push_back(dwarf::DW_OP_stack_value);
 
-  return DIExpression::get(Expr->getContext(), NewOps);
+  return DIExpression::get(Expr->getContext(), NewOps)->foldConstantMath();
 }
 
 DIExpression *DIExpression::replaceArg(const DIExpression *Expr,
diff --git a/llvm/test/DebugInfo/MIR/InstrRef/deref-spills-with-size.mir b/llvm/test/DebugInfo/MIR/InstrRef/deref-spills-with-size.mir
index 0253c95cc1324b..0ab3ec62f35467 100644
--- a/llvm/test/DebugInfo/MIR/InstrRef/deref-spills-with-size.mir
+++ b/llvm/test/DebugInfo/MIR/InstrRef/deref-spills-with-size.mir
@@ -83,9 +83,9 @@
 # DWARF-NEXT: DW_OP_breg7 RSP-8
 # DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_stack_value
 ## scalar / stack value with various sizes.
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value)
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_plus_uconst 0x1, DW_OP_stack_value
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref, DW_OP_plus_uconst 0x1, DW_OP_stack_value
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_plus_uconst 0x1, DW_OP_stack_value)
 # DWARF:      DW_AT_name ("flannel")
 
 # Variable with fragments.
@@ -96,9 +96,9 @@
 # DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_piece 0x4
 # DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_stack_value, DW_OP_piece 0x4
 ## Scalar / stack value with various sizes.
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value, DW_OP_piece 0x4
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x4, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value, DW_OP_piece 0x4
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value, DW_OP_piece 0x4)
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_plus_uconst 0x1, DW_OP_stack_value, DW_OP_piece 0x4
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x4, DW_OP_plus_uconst 0x1, DW_OP_stack_value, DW_OP_piece 0x4
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_plus_uconst 0x1, DW_OP_stack_value, DW_OP_piece 0x4)
 # DWARF:      DW_AT_name ("shoes")
 
 --- |
@@ -308,7 +308,7 @@ body:             |
     $rax = MOV64ri 0, debug-location !7
     DBG_INSTR_REF !8, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), dbg-instr-ref(16, 0), debug-location !7
     ; CHECK:      DBG_VALUE_LIST ![[VARNUM]],
-    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 8, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), $rsp
+    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 8, DW_OP_plus_uconst, 1, DW_OP_stack_value), $rsp
     $eax = MOV32ri 0, debug-location !7
     DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
     ; CHECK: DBG_VALUE $noreg, $noreg
@@ -319,7 +319,7 @@ body:             |
     $rax = MOV64ri 0, debug-location !7
     DBG_INSTR_REF !8, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), dbg-instr-ref(17, 0), debug-location !7
     ; CHECK:      DBG_VALUE_LIST ![[VARNUM]],
-    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), $rsp
+    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref, DW_OP_plus_uconst, 1, DW_OP_stack_value), $rsp
     $eax = MOV32ri 0, debug-location !7
     DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
     ; CHECK: DBG_VALUE $noreg, $noreg
@@ -330,7 +330,7 @@ body:             |
     $rax = MOV64ri 0, debug-location !7
     DBG_INSTR_REF !8, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), dbg-instr-ref(18, 0), debug-location !7
     ; CHECK:      DBG_VALUE_LIST ![[VARNUM]],
-    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 1, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), $rsp
+    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 1, DW_OP_plus_uconst, 1, DW_OP_stack_value), $rsp
     $eax = MOV32ri 0, debug-location !7
     DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
     ; CHECK: DBG_VALUE $noreg, $noreg
@@ -341,7 +341,7 @@ body:             |
     $rax = MOV64ri 0, debug-location !7
     DBG_INSTR_REF !10, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), dbg-instr-ref(19, 0), debug-location !7
     ; CHECK:      DBG_VALUE_LIST ![[VARNUM2]],
-    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 8, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), $rsp
+    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 8, DW_OP_plus_uconst, 1, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), $rsp
     $eax = MOV32ri 0, debug-location !7
     DBG_VALUE $noreg, $noreg, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
     ; CHECK: DBG_VALUE $noreg, $noreg
@@ -352,7 +352,7 @@ body:             |
     $rax = MOV64ri 0, debug-location !7
     DBG_INSTR_REF !10, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), dbg-instr-ref(20, 0), debug-location !7
     ; CHECK:      DBG_VALUE_LIST ![[VARNUM2]],
-    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 4, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), $rsp
+    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 4, DW_OP_plus_uconst, 1, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), $rsp
     $eax = MOV32ri 0, debug-location !7
     DBG_VALUE $noreg, $noreg, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
     ; CHECK: DBG_VALUE $noreg, $noreg
@@ -363,7 +363,7 @@ body:             |
     $rax = MOV64ri 0, debug-location !7
     DBG_INSTR_REF !10, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), dbg-instr-ref(21, 0), debug-location !7
     ; CHECK:      DBG_VALUE_LIST ![[VARNUM2]],
-    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 1, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), $rsp
+    ; CHECK-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 1, DW_OP_plus_uconst, 1, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), $rsp
     $eax = MOV32ri 0, debug-location !7
     DBG_VALUE $noreg, $noreg, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
     ; CHECK: DBG_VALUE $noreg, $noreg
diff --git a/llvm/test/DebugInfo/MIR/InstrRef/follow-spill-of-indir-value.mir b/llvm/test/DebugInfo/MIR/InstrRef/follow-spill-of-indir-value.mir
index e3b8df27785434..d3541b4845721b 100644
--- a/llvm/test/DebugInfo/MIR/InstrRef/follow-spill-of-indir-value.mir
+++ b/llvm/test/DebugInfo/MIR/InstrRef/follow-spill-of-indir-value.mir
@@ -27,7 +27,7 @@
 ## 
 ## Second location, variable pointed to by the register value plus eight.
 ##
-# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref, DW_OP_lit8, DW_OP_plus)
+# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref, DW_OP_plus_uconst 0x8)
 ##
 ## Spilt to stack: push stack location and deref the pointer onto the dwarf
 ## expr stack. Then add eight to it, and it points to the variable.
@@ -135,7 +135,7 @@ body:             |
     ; CHECK: DBG_VALUE $rdi,
     MOV64mr $rsp, 1, $noreg, -8, $noreg, $rdi :: (store (s64) into %stack.0)
     $rdi = MOV64ri 0
-    ; CHECK: DBG_VALUE $rsp, 0, ![[VARNUM]], !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref, DW_OP_constu, 8, DW_OP_plus),
+    ; CHECK: DBG_VALUE $rsp, 0, ![[VARNUM]], !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref, DW_OP_plus_uconst, 8),
 
     renamable $rax = MOV64rm $rsp, 1, $noreg, -8, $noreg :: (load (s64) from %stack.0)
     renamable $eax = MOV32rm killed renamable $rax, 1, $noreg, 0, $noreg, debug-location !24 :: (load (s32) from %ir.i1, !tbaa !25)
diff --git a/llvm/test/DebugInfo/salvage-icmp.ll b/llvm/test/DebugInfo/salvage-icmp.ll
index ce9e809e12c1a8..f47c20e7992e65 100644
--- a/llvm/test/DebugInfo/salvage-icmp.ll
+++ b/llvm/test/DebugInfo/salvage-icmp.ll
@@ -5,7 +5,7 @@
 
 ; CHECK: call void @llvm.dbg.value(metadata i32 %a,
 ; CHECK-SAME: ![[VAR_C:[0-9]+]],
-; CHECK-SAME: !DIExpression(DW_OP_constu, 0, DW_OP_ne, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 0, DW_OP_eq, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 1, DW_OP_gt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551615, DW_OP_gt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 2, DW_OP_ge, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551614, DW_OP_ge, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 3, DW_OP_lt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551613, DW_OP_lt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 4, DW_OP_le, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551612, DW_OP_le, DW_OP_stack_value))
+; CHECK-SAME: !DIExpression(DW_OP_lit0, DW_OP_ne, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_lit0, DW_OP_eq, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 1, DW_OP_gt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551615, DW_OP_gt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 2, DW_OP_ge, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551614, DW_OP_ge, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 3, DW_OP_lt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551613, DW_OP_lt, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_constu, 4, DW_OP_le, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_consts, 18446744073709551612, DW_OP_le, DW_OP_stack_value))
 
 ; CHECK: call void @llvm.dbg.value(metadata !DIArgList(i32 %a, i32 %a, i32 %a, i32 %b, i32 %a, i32 %b, i32 %b, i32 %a, i32 %a, i32 %b, i32 %b),
 ; CHECK-SAME: ![[VAR_C:[0-9]+]],
diff --git a/llvm/test/Transforms/Coroutines/swift-async-dbg.ll b/llvm/test/Transforms/Coroutines/swift-async-dbg.ll
index 74edf7a3f3a540..548b3eddb39d37 100644
--- a/llvm/test/Transforms/Coroutines/swift-async-dbg.ll
+++ b/llvm/test/Transforms/Coroutines/swift-async-dbg.ll
@@ -30,7 +30,7 @@ define swifttailcc void @coroutineA(ptr swiftasync %arg) !dbg !48 {
 ; CHECK-LABEL: define {{.*}} @coroutineA(
 ; CHECK-SAME:    ptr swiftasync %[[frame_ptr:.*]])
 ; CHECK:      @llvm.dbg.declare(metadata ptr %[[frame_ptr]], {{.*}} !DIExpression(
-; CHECK-SAME:                   DW_OP_plus_uconst, 16, DW_OP_plus_uconst, 8)
+; CHECK-SAME:                   DW_OP_plus_uconst, 24)
 ; CHECK:      @llvm.dbg.value(metadata ptr %[[frame_ptr]], {{.*}} !DIExpression(
 ; CHECK-SAME:                 DW_OP_plus_uconst, 16, DW_OP_deref)
 ; CHECK:      call {{.*}} @swift_task_switch
@@ -49,7 +49,7 @@ define swifttailcc void @coroutineA(ptr swiftasync %arg) !dbg !48 {
 ; CHECK-LABEL: define {{.*}} @coroutineATY0_(
 ; CHECK-SAME:    ptr swiftasync %[[frame_ptr:.*]])
 ; CHECK:      @llvm.dbg.declare(metadata ptr %[[frame_ptr]], {{.*}} !DIExpression(
-; CHECK-SAME:                   DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 16, DW_OP_plus_uconst, 8)
+; CHECK-SAME:                   DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 24)
 ; CHECK:      @llvm.dbg.value(metadata ptr %[[frame_ptr]], {{.*}} !DIExpression(
 ; CHECK-SAME:                 DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 16, DW_OP_deref)
 ; CHECK:      @llvm.dbg.value(metadata !DIArgList(ptr %[[frame_ptr]], i32 %{{.*}}), {{.*}} !DIExpression(
@@ -70,7 +70,7 @@ define swifttailcc void @coroutineA(ptr swiftasync %arg) !dbg !48 {
 ; CHECK-SAME:    ptr swiftasync %[[frame_ptr:.*]])
 ; Note the extra level of indirection that shows up here!
 ; CHECK:      @llvm.dbg.declare(metadata ptr %[[frame_ptr]], {{.*}} !DIExpression(
-; CHECK-SAME:                   DW_OP_LLVM_entry_value, 1, DW_OP_deref, DW_OP_plus_uconst, 16, DW_OP_plus_uconst, 8)
+; CHECK-SAME:                   DW_OP_LLVM_entry_value, 1, DW_OP_deref, DW_OP_plus_uconst, 24)
 ; CHECK:      @llvm.dbg.value(metadata ptr %[[frame_ptr]], {{.*}} !DIExpression(
 ; CHECK-SAME:                 DW_OP_LLVM_entry_value, 1, DW_OP_deref, DW_OP_plus_uconst, 16, DW_OP_deref)
 ; CHECK:      call {{.*}} @swift_task_switch
@@ -85,7 +85,7 @@ define swifttailcc void @coroutineA(ptr swiftasync %arg) !dbg !48 {
 ; CHECK-LABEL: define {{.*}} @coroutineATY2_(
 ; CHECK-SAME:    ptr swiftasync %[[frame_ptr:.*]])
 ; CHECK:      @llvm.dbg.declare(metadata ptr %[[frame_ptr]], {{.*}} !DIExpression(
-; CHECK-SAME:                   DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 16, DW_OP_plus_uconst, 8)
+; CHECK-SAME:                   DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 24)
 }
 
 ; Everything from here on is just support code for the coroutines.
diff --git a/llvm/test/Transforms/InstCombine/cast-mul-select.ll b/llvm/test/Transforms/InstCombine/cast-mul-select.ll
index 50769ebe76f5c5..79d7ac9e6d0bed 100644
--- a/llvm/test/Transforms/InstCombine/cast-mul-select.ll
+++ b/llvm/test/Transforms/InstCombine/cast-mul-select.ll
@@ -207,7 +207,7 @@ define void @PR36225(i32 %a, i32 %b, i1 %c1, i3 %v1, i3 %v2) {
 ; DBGINFO-NEXT:  entry:
 ; DBGINFO-NEXT:    br label [[WHILE_BODY:%.*]], !dbg [[DBG94:![0-9]+]]
 ; DBGINFO:       while.body:
-; DBGINFO-NEXT:    call void @llvm.dbg.value(metadata i32 [[B:%.*]], metadata [[META89:![0-9]+]], metadata !DIExpression(DW_OP_constu, 0, DW_OP_eq, DW_OP_stack_value)), !dbg [[DBG95:![0-9]+]]
+; DBGINFO-NEXT:    call void @llvm.dbg.value(metadata i32 [[B:%.*]], metadata [[META89:![0-9]+]], metadata !DIExpression(DW_OP_lit0, DW_OP_eq, DW_OP_stack_value)), !dbg [[DBG95:![0-9]+]]
 ; DBGINFO-NEXT:    br i1 [[C1:%.*]], label [[FOR_BODY3_US:%.*]], label [[FOR_BODY3:%.*]], !dbg [[DBG96:![0-9]+]]
 ; DBGINFO:       for.body3.us:
 ; DBGINFO-NEXT:    [[TOBOOL:%.*]] = icmp eq i32 [[B]], 0, !dbg [[DBG95]]
diff --git a/llvm/test/Transforms/InstCombine/debuginfo-dce.ll b/llvm/test/Transforms/InstCombine/debuginfo-dce.ll
index 257222cb70c238..27e0580804cae7 100644
--- a/llvm/test/Transforms/InstCombine/debuginfo-dce.ll
+++ b/llvm/test/Transforms/InstCombine/debuginfo-dce.ll
@@ -61,7 +61,7 @@ entry:
 ; CHECK: define void @salvage_gep0
 ; CHECK-NEXT: entry:
 ; CHECK-NEXT: call void @llvm.dbg.value(metadata ptr %queue,
-; CHECK-SAME:                           metadata !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_plus_uconst, 0, DW_OP_stack_value))
+; CHECK-SAME:                           metadata !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_stack_value))
   store ptr %1, ptr %im_not_dead, align 8
   ret void, !dbg !26
 }
diff --git a/llvm/test/Transforms/InstCombine/debuginfo-sink.ll b/llvm/test/Transforms/InstCombine/debuginfo-sink.ll
index 0c7d30d70c366b..63f09d26cce4f9 100644
--- a/llvm/test/Transforms/InstCombine/debuginfo-sink.ll
+++ b/llvm/test/Transforms/InstCombine/debuginfo-sink.ll
@@ -54,33 +54,33 @@ sink2:
   ret i32 %extract
 }
 
-; This GEP is sunk, and has multiple debug uses in the same block. Check that
-; only the last use is cloned into the sunk block, and that both of the
-; original dbg.values are salvaged.
-;
-; CHECK-LABEL: define i32 @baz(ptr
-; CHECK:       call void @llvm.dbg.value(metadata ptr %a, metadata !{{[0-9]+}},
-; CHECK-SAME:  metadata !DIExpression(DW_OP_plus_uconst, 4, DW_OP_stack_value))
-; CHECK-NEXT:  call void @llvm.dbg.value(metadata ptr %a, metadata !{{[0-9]+}},
-; CHECK-SAME:  metadata !DIExpression(DW_OP_plus_uconst, 4, DW_OP_plus_uconst, 5, DW_OP_stack_value))
-; CHECK-NEXT:  br label %sink1
-
-define i32 @baz(ptr %a) !dbg !80 {
-entry:
-  %gep = getelementptr i32, ptr %a, i32 1
-  call void @llvm.dbg.value(metadata ptr %gep, metadata !83, metadata !12), !dbg !84
-  call void @llvm.dbg.value(metadata ptr %gep, metadata !83, metadata !DIExpression(DW_OP_plus_uconst, 5)), !dbg !85
-  br label %sink1
-
-sink1:
-; CHECK-LABEL: sink1:
-; CHECK:       call void @llvm.dbg.value(metadata ptr %gep,
-; CHECK-SAME:  metadata !{{[0-9]+}}, metadata !DIExpression(DW_OP_plus_uconst, 5))
-; CHECK-NEXT:  load
-  %0 = load i32, ptr %gep, align 4, !dbg !85
-  ret i32 %0, !dbg !85
-}
-
+; This GEP is sunk, and has multiple debug uses in the same block. Check that
+; only the last use is cloned into the sunk block, and that both of the
+; original dbg.values are salvaged.
+;
+; CHECK-LABEL: define i32 @baz(ptr
+; CHECK:       call void @llvm.dbg.value(metadata ptr %a, metadata !{{[0-9]+}},
+; CHECK-SAME:  metadata !DIExpression(DW_OP_plus_uconst, 4, DW_OP_stack_value))
+; CHECK-NEXT:  call void @llvm.dbg.value(metadata ptr %a, metadata !{{[0-9]+}},
+; CHECK-SAME:  metadata !DIExpression(DW_OP_plus_uconst, 9, DW_OP_stack_value))
+; CHECK-NEXT:  br label %sink1
+
+define i32 @baz(ptr %a) !dbg !80 {
+entry:
+  %gep = getelementptr i32, ptr %a, i32 1
+  call void @llvm.dbg.value(metadata ptr %gep, metadata !83, metadata !12), !dbg !84
+  call void @llvm.dbg.value(metadata ptr %gep, metadata !83, metadata !DIExpression(DW_OP_plus_uconst, 5)), !dbg !85
+  br label %sink1
+
+sink1:
+; CHECK-LABEL: sink1:
+; CHECK:       call void @llvm.dbg.value(metadata ptr %gep,
+; CHECK-SAME:  metadata !{{[0-9]+}}, metadata !DIExpression(DW_OP_plus_uconst, 5))
+; CHECK-NEXT:  load
+  %0 = load i32, ptr %gep, align 4, !dbg !85
+  ret i32 %0, !dbg !85
+}
+
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!3, !4, !5}
 !llvm.ident = !{!6}
@@ -105,7 +105,7 @@ sink1:
 !72 = !{!10, !10, !10}
 !73 = !DILocalVariable(name: "k", scope: !70, file: !1, line: 2, type: !10)
 !74 = !DILocation(line: 5, column: 3, scope: !70)
-!80 = distinct !DISubprogram(name: "baz", scope: !1, file: !1, line: 2, type: !8, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
-!83 = !DILocalVariable(name: "l", scope: !80, file: !1, line: 2, type: !10)
-!84 = !DILocation(line: 5, column: 3, scope: !80)
-!85 = !DILocation(line: 6, column: 3, scope: !80)
+!80 = distinct !DISubprogram(name: "baz", scope: !1, file: !1, line: 2, type: !8, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
+!83 = !DILocalVariable(name: "l", scope: !80, file: !1, line: 2, type: !10)
+!84 = !DILocation(line: 5, column: 3, scope: !80)
+!85 = !DILocation(line: 6, column: 3, scope: !80)
diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
index 8368b83a6d4684..03b8758754b9cb 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -3412,6 +3412,9 @@ TEST_F(DIExpressionTest, Append) {
                                      dwarf::DW_OP_plus_uconst, 5};
   auto *ResExpr = DIExpression::get(Context, OpsRes);
   EXPECT_EQ(ResExpr, AppendExpr);
+  auto *AppendToArgExpr =
+      DIExpression::appendOpsToArg(Expr, AppendOps, 0, false);
+  EXPECT_EQ(ResExpr, AppendToArgExpr);
 
   // Test appending a {dwarf::DW_OP_plus_uconst, <const>} to a DW_OP_plus
   // expression uint64_t PlusUConstOps[] = {dwarf::DW_OP_plus_uconst, 3};
@@ -3426,6 +3429,8 @@ TEST_F(DIExpressionTest, Append) {
   OpsRes.push_back(5);
   ResExpr = DIExpression::get(Context, OpsRes);
   EXPECT_EQ(ResExpr, AppendExpr);
+  AppendToArgExpr = DIExpression::appendOpsToArg(Expr, AppendOps, 0, false);
+  EXPECT_EQ(ResExpr, AppendToArgExpr);
 
   // Test appending a {dwarf::DW_OP_constu, 0, DW_OP_plus} to an expression
   AppendOps[0] = dwarf::DW_OP_constu;
@@ -3436,6 +3441,8 @@ TEST_F(DIExpressionTest, Append) {
   OpsRes[3] = Ops[3];
   ResExpr = DIExpression::get(Context, OpsRes);
   EXPECT_EQ(ResExpr, AppendExpr);
+  AppendToArgExpr = DIExpression::appendOpsToArg(Expr, AppendOps, 0, false);
+  EXPECT_EQ(ResExpr, AppendToArgExpr);
 
   // Test appending a {dwarf::DW_OP_constu, 0, DW_OP_minus} to an expression
   AppendOps[2] = dwarf::DW_OP_minus;
@@ -3443,6 +3450,8 @@ TEST_F(DIExpressionTest, Append) {
   OpsRes[3] = Ops[3];
   ResExpr = DIExpression::get(Context, OpsRes);
   EXPECT_EQ(ResExpr, AppendExpr);
+  AppendToArgExpr = DIExpression::appendOpsToArg(Expr, AppendOps, 0, false);
+  EXPECT_EQ(ResExpr, AppendToArgExpr);
 
   // Test appending a {dwarf::DW_OP_constu, 0, DW_OP_shl} to an expression
   AppendOps[2] = dwarf::DW_OP_shl;
@@ -3450,6 +3459,8 @@ TEST_F(DIExpressionTest, Append) {
   OpsRes[3] = Ops[3];
   ResExpr = DIExpression::get(Context, OpsRes);
   EXPECT_EQ(ResExpr, AppendExpr);
+  AppendToArgExpr = DIExpression::appendOpsToArg(Expr, AppendOps, 0, false);
+  EXPECT_EQ(ResExpr, AppendToArgExpr);
 
   // Test appending a {dwarf::DW_OP_constu, 0, DW_OP_shr} to an expression
   AppendOps[2] = dwarf::DW_OP_shr;
@@ -3457,6 +3468,8 @@ TEST_F(DIExpressionTest, Append) {
   OpsRes[3] = Ops[3];
   ResExpr = DIExpression::get(Context, OpsRes);
   EXPECT_EQ(ResExpr, AppendExpr);
+  AppendToArgExpr = DIExpression::appendOpsToArg(Expr, AppendOps, 0, false);
+  EXPECT_EQ(ResExpr, AppendToArgExpr);
 
   // Test appending a {dwarf::DW_OP_constu, <const>, DW_OP_mul} to a DW_OP_mul
   // expression
@@ -3470,6 +3483,8 @@ TEST_F(DIExpressionTest, Append) {
   OpsRes.push_back(dwarf::DW_OP_mul);
   ResExpr = DIExpression::get(Context, OpsRes);
   EXPECT_EQ(ResExpr, AppendExpr);
+  AppendToArgExpr = DIExpression::appendOpsToArg(Expr, AppendOps, 0, false);
+  EXPECT_EQ(ResExpr, AppendToArgExpr);
 
   // Test appending a {dwarf::DW_OP_constu, 1, DW_OP_mul} to an expression
   AppendOps[1] = 1;
@@ -3477,6 +3492,8 @@ TEST_F(DIExpressionTest, Append) {
   OpsRes[3] = Ops[3];
   ResExpr = DIExpression::get(Context, OpsRes);
   EXPECT_EQ(ResExpr, AppendExpr);
+  AppendToArgExpr = DIExpression::appendOpsToArg(Expr, AppendOps, 0, false);
+  EXPECT_EQ(ResExpr, AppendToArgExpr);
 
   // Test appending a {dwarf::DW_OP_constu, 1, DW_OP_div} to an expression
   AppendOps[1] = 1;
@@ -3485,6 +3502,8 @@ TEST_F(DIExpressionTest, Append) {
   OpsRes[3] = Ops[3];
   ResExpr = DIExpression::get(Context, OpsRes);
   EXPECT_EQ(ResExpr, AppendExpr);
+  AppendToArgExpr = DIExpression::appendOpsToArg(Expr, AppendOps, 0, false);
+  EXPECT_EQ(ResExpr, AppendToArgExpr);
 }
 
 TEST_F(DIExpressionTest, isValid) {
diff --git a/llvm/unittests/Transforms/Utils/LocalTest.cpp b/llvm/unittests/Transforms/Utils/LocalTest.cpp
index 82257741045754..2d83e09e9af2f4 100644
--- a/llvm/unittests/Transforms/Utils/LocalTest.cpp
+++ b/llvm/unittests/Transforms/Utils/LocalTest.cpp
@@ -544,8 +544,7 @@ struct SalvageDebugInfoTest : ::testing::Test {
     const auto &CI = *cast<ConstantInt>(DI.getVariableLocationOp(0));
     if (CI.isZero())
       return DI.getExpression()->getElements().equals(
-          {dwarf::DW_OP_plus_uconst, 1, dwarf::DW_OP_plus_uconst, 2,
-           dwarf::DW_OP_stack_value});
+          {dwarf::DW_OP_plus_uconst, 3, dwarf::DW_OP_stack_value});
     else if (CI.isOneValue())
       return DI.getExpression()->getElements().equals(
           {dwarf::DW_OP_plus_uconst, 2, dwarf::DW_OP_stack_value});



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