Commit 8d5aeb26 authored by Duncan P. N. Exon Smith's avatar Duncan P. N. Exon Smith
Browse files

IR: Move NumOperands from User to Value, NFC 

Store `User::NumOperands` (and `MDNode::NumOperands`) in `Value`.

On 64-bit host architectures, this reduces `sizeof(User)` and all
subclasses by 8, and has no effect on `sizeof(Value)` (or, incidentally,
on `sizeof(MDNode)`).

On 32-bit host architectures, this increases `sizeof(Value)` by 4.
However, it has no effect on `sizeof(User)` and `sizeof(MDNode)`, so the
only concrete subclasses of `Value` that actually see the increase are
`BasicBlock`, `Argument`, `InlineAsm`, and `MDString`.  Moreover, I'll
be shocked and confused if this causes a tangible memory regression.

This has no functionality change (other than memory footprint).

llvm-svn: 219845
parent fcece4d2

llvm/include/llvm/IR/Metadata.h

+0 −3
Original line number Diff line number Diff line
@@ -126,9 +126,6 @@ class MDNode : public Value, public FoldingSetNode { 
  /// \brief If the MDNode is uniqued cache the hash to speed up lookup.

  unsigned Hash;



  /// \brief Number of co-allocated 'MDNodeOperand' items.

  unsigned NumOperands;



  /// \brief Subclass data enums.

  enum {

    /// FunctionLocalBit - This bit is set if this MDNode is function local.

llvm/include/llvm/IR/User.h

+3 −4
Original line number Diff line number Diff line
@@ -39,9 +39,6 @@ class User : public Value { 
  friend struct HungoffOperandTraits;

  virtual void anchor();

protected:

  /// \brief The number of values used by this User.

  unsigned NumOperands;



  /// \brief This is a pointer to the array of Uses for this User.

  ///

  /// For nodes of fixed arity (e.g. a binary operator) this array will live
@@ -52,7 +49,9 @@ protected: 


  void *operator new(size_t s, unsigned Us);

  User(Type *ty, unsigned vty, Use *OpList, unsigned NumOps)

    : Value(ty, vty), NumOperands(NumOps), OperandList(OpList) {}

      : Value(ty, vty), OperandList(OpList) {

    NumOperands = NumOps;

  }

  Use *allocHungoffUses(unsigned) const;

  void dropHungoffUses() {

    Use::zap(OperandList, OperandList + NumOperands, true);

llvm/include/llvm/IR/Value.h

+13 −0
Original line number Diff line number Diff line
@@ -92,6 +92,19 @@ private: 
  /// field is initialized to zero by the ctor.

  unsigned short SubclassData;



protected:

  /// \brief The number of operands in the subclass.

  ///

  /// This member is defined by this class, but not used for anything.

  /// Subclasses can use it to store their number of operands, if they have

  /// any.

  ///

  /// This is stored here to save space in User on 64-bit hosts.  Since most

  /// instances of Value have operands, 32-bit hosts aren't significantly

  /// affected.

  unsigned NumOperands;



private:

  template <typename UseT> // UseT == 'Use' or 'const Use'

  class use_iterator_impl

      : public std::iterator<std::forward_iterator_tag, UseT *, ptrdiff_t> {

llvm/lib/IR/Value.cpp

+2 −1
Original line number Diff line number Diff line
@@ -45,7 +45,8 @@ static inline Type *checkType(Type *Ty) { 


Value::Value(Type *ty, unsigned scid)

    : VTy(checkType(ty)), UseList(nullptr), Name(nullptr), SubclassID(scid),

      HasValueHandle(0), SubclassOptionalData(0), SubclassData(0) {

      HasValueHandle(0), SubclassOptionalData(0), SubclassData(0),

      NumOperands(0) {

  // FIXME: Why isn't this in the subclass gunk??

  // Note, we cannot call isa<CallInst> before the CallInst has been

  // constructed.