[SDAG][NFC] Convert SDNodeFlags into an enumeration (llvm#114167)

This patch converts `SDNodeFlags` into an enumeration as we did for
`FastMathFlags`. It simplifies the implementation and improves
compile-time. This patch is NFC since it doesn't break SDNodeFlags API.

Author: dtcxzyw

llvm/include/llvm/CodeGen/SelectionDAGNodes.h

@@ -378,36 +378,48 @@ template<> struct simplify_type<SDUse> {
 /// the backend.
 struct SDNodeFlags {
 private:
-  bool NoUnsignedWrap : 1;
-  bool NoSignedWrap : 1;
-  bool Exact : 1;
-  bool Disjoint : 1;
-  bool NonNeg : 1;
-  bool NoNaNs : 1;
-  bool NoInfs : 1;
-  bool NoSignedZeros : 1;
-  bool AllowReciprocal : 1;
-  bool AllowContract : 1;
-  bool ApproximateFuncs : 1;
-  bool AllowReassociation : 1;
-
-  // We assume instructions do not raise floating-point exceptions by default,
-  // and only those marked explicitly may do so.  We could choose to represent
-  // this via a positive "FPExcept" flags like on the MI level, but having a
-  // negative "NoFPExcept" flag here makes the flag intersection logic more
-  // straightforward.
-  bool NoFPExcept : 1;
-  // Instructions with attached 'unpredictable' metadata on IR level.
-  bool Unpredictable : 1;
+  friend class SDNode;
+
+  unsigned Flags = 0;
+
+  template <unsigned Flag> void setFlag(bool B) {
+    Flags = (Flags & ~Flag) | (B ? Flag : 0);
+  }
 
 public:
+  enum : unsigned {
+    None = 0,
+    NoUnsignedWrap = 1 << 0,
+    NoSignedWrap = 1 << 1,
+    Exact = 1 << 2,
+    Disjoint = 1 << 3,
+    NonNeg = 1 << 4,
+    NoNaNs = 1 << 5,
+    NoInfs = 1 << 6,
+    NoSignedZeros = 1 << 7,
+    AllowReciprocal = 1 << 8,
+    AllowContract = 1 << 9,
+    ApproximateFuncs = 1 << 10,
+    AllowReassociation = 1 << 11,
+
+    // We assume instructions do not raise floating-point exceptions by default,
+    // and only those marked explicitly may do so.  We could choose to represent
+    // this via a positive "FPExcept" flags like on the MI level, but having a
+    // negative "NoFPExcept" flag here makes the flag intersection logic more
+    // straightforward.
+    NoFPExcept = 1 << 12,
+    // Instructions with attached 'unpredictable' metadata on IR level.
+    Unpredictable = 1 << 13,
+
+    // NOTE: Please update LargestValue in LLVM_DECLARE_ENUM_AS_BITMASK below
+    // the class definition when adding new flags.
+
+    PoisonGeneratingFlags = NoUnsignedWrap | NoSignedWrap | Exact | Disjoint |
+                            NonNeg | NoNaNs | NoInfs,
+  };
+
   /// Default constructor turns off all optimization flags.
-  SDNodeFlags()
-      : NoUnsignedWrap(false), NoSignedWrap(false), Exact(false),
-        Disjoint(false), NonNeg(false), NoNaNs(false), NoInfs(false),
-        NoSignedZeros(false), AllowReciprocal(false), AllowContract(false),
-        ApproximateFuncs(false), AllowReassociation(false), NoFPExcept(false),
-        Unpredictable(false) {}
+  SDNodeFlags() : Flags(0) {}
 
   /// Propagate the fast-math-flags from an IR FPMathOperator.
   void copyFMF(const FPMathOperator &FPMO) {
@@ -421,71 +433,49 @@ struct SDNodeFlags {
   }
 
   // These are mutators for each flag.
-  void setNoUnsignedWrap(bool b) { NoUnsignedWrap = b; }
-  void setNoSignedWrap(bool b) { NoSignedWrap = b; }
-  void setExact(bool b) { Exact = b; }
-  void setDisjoint(bool b) { Disjoint = b; }
-  void setNonNeg(bool b) { NonNeg = b; }
-  void setNoNaNs(bool b) { NoNaNs = b; }
-  void setNoInfs(bool b) { NoInfs = b; }
-  void setNoSignedZeros(bool b) { NoSignedZeros = b; }
-  void setAllowReciprocal(bool b) { AllowReciprocal = b; }
-  void setAllowContract(bool b) { AllowContract = b; }
-  void setApproximateFuncs(bool b) { ApproximateFuncs = b; }
-  void setAllowReassociation(bool b) { AllowReassociation = b; }
-  void setNoFPExcept(bool b) { NoFPExcept = b; }
-  void setUnpredictable(bool b) { Unpredictable = b; }
+  void setNoUnsignedWrap(bool b) { setFlag<NoUnsignedWrap>(b); }
+  void setNoSignedWrap(bool b) { setFlag<NoSignedWrap>(b); }
+  void setExact(bool b) { setFlag<Exact>(b); }
+  void setDisjoint(bool b) { setFlag<Disjoint>(b); }
+  void setNonNeg(bool b) { setFlag<NonNeg>(b); }
+  void setNoNaNs(bool b) { setFlag<NoNaNs>(b); }
+  void setNoInfs(bool b) { setFlag<NoInfs>(b); }
+  void setNoSignedZeros(bool b) { setFlag<NoSignedZeros>(b); }
+  void setAllowReciprocal(bool b) { setFlag<AllowReciprocal>(b); }
+  void setAllowContract(bool b) { setFlag<AllowContract>(b); }
+  void setApproximateFuncs(bool b) { setFlag<ApproximateFuncs>(b); }
+  void setAllowReassociation(bool b) { setFlag<AllowReassociation>(b); }
+  void setNoFPExcept(bool b) { setFlag<NoFPExcept>(b); }
+  void setUnpredictable(bool b) { setFlag<Unpredictable>(b); }
 
   // These are accessors for each flag.
-  bool hasNoUnsignedWrap() const { return NoUnsignedWrap; }
-  bool hasNoSignedWrap() const { return NoSignedWrap; }
-  bool hasExact() const { return Exact; }
-  bool hasDisjoint() const { return Disjoint; }
-  bool hasNonNeg() const { return NonNeg; }
-  bool hasNoNaNs() const { return NoNaNs; }
-  bool hasNoInfs() const { return NoInfs; }
-  bool hasNoSignedZeros() const { return NoSignedZeros; }
-  bool hasAllowReciprocal() const { return AllowReciprocal; }
-  bool hasAllowContract() const { return AllowContract; }
-  bool hasApproximateFuncs() const { return ApproximateFuncs; }
-  bool hasAllowReassociation() const { return AllowReassociation; }
-  bool hasNoFPExcept() const { return NoFPExcept; }
-  bool hasUnpredictable() const { return Unpredictable; }
+  bool hasNoUnsignedWrap() const { return Flags & NoUnsignedWrap; }
+  bool hasNoSignedWrap() const { return Flags & NoSignedWrap; }
+  bool hasExact() const { return Flags & Exact; }
+  bool hasDisjoint() const { return Flags & Disjoint; }
+  bool hasNonNeg() const { return Flags & NonNeg; }
+  bool hasNoNaNs() const { return Flags & NoNaNs; }
+  bool hasNoInfs() const { return Flags & NoInfs; }
+  bool hasNoSignedZeros() const { return Flags & NoSignedZeros; }
+  bool hasAllowReciprocal() const { return Flags & AllowReciprocal; }
+  bool hasAllowContract() const { return Flags & AllowContract; }
+  bool hasApproximateFuncs() const { return Flags & ApproximateFuncs; }
+  bool hasAllowReassociation() const { return Flags & AllowReassociation; }
+  bool hasNoFPExcept() const { return Flags & NoFPExcept; }
+  bool hasUnpredictable() const { return Flags & Unpredictable; }
 
   bool operator==(const SDNodeFlags &Other) const {
-    return NoUnsignedWrap == Other.NoUnsignedWrap &&
-           NoSignedWrap == Other.NoSignedWrap && Exact == Other.Exact &&
-           Disjoint == Other.Disjoint && NonNeg == Other.NonNeg &&
-           NoNaNs == Other.NoNaNs && NoInfs == Other.NoInfs &&
-           NoSignedZeros == Other.NoSignedZeros &&
-           AllowReciprocal == Other.AllowReciprocal &&
-           AllowContract == Other.AllowContract &&
-           ApproximateFuncs == Other.ApproximateFuncs &&
-           AllowReassociation == Other.AllowReassociation &&
-           NoFPExcept == Other.NoFPExcept &&
-           Unpredictable == Other.Unpredictable;
+    return Flags == Other.Flags;
   }
 
   /// Clear any flags in this flag set that aren't also set in Flags. All
   /// flags will be cleared if Flags are undefined.
-  void intersectWith(const SDNodeFlags Flags) {
-    NoUnsignedWrap &= Flags.NoUnsignedWrap;
-    NoSignedWrap &= Flags.NoSignedWrap;
-    Exact &= Flags.Exact;
-    Disjoint &= Flags.Disjoint;
-    NonNeg &= Flags.NonNeg;
-    NoNaNs &= Flags.NoNaNs;
-    NoInfs &= Flags.NoInfs;
-    NoSignedZeros &= Flags.NoSignedZeros;
-    AllowReciprocal &= Flags.AllowReciprocal;
-    AllowContract &= Flags.AllowContract;
-    ApproximateFuncs &= Flags.ApproximateFuncs;
-    AllowReassociation &= Flags.AllowReassociation;
-    NoFPExcept &= Flags.NoFPExcept;
-    Unpredictable &= Flags.Unpredictable;
-  }
+  void intersectWith(const SDNodeFlags Flags) { this->Flags &= Flags.Flags; }
 };
 
+LLVM_DECLARE_ENUM_AS_BITMASK(decltype(SDNodeFlags::None),
+                             SDNodeFlags::Unpredictable);
+
 /// Represents one node in the SelectionDAG.
 ///
 class SDNode : public FoldingSetNode, public ilist_node<SDNode> {
@@ -1029,10 +1019,7 @@ END_TWO_BYTE_PACK()
   void intersectFlagsWith(const SDNodeFlags Flags);
 
   bool hasPoisonGeneratingFlags() const {
-    SDNodeFlags Flags = getFlags();
-    return Flags.hasNoUnsignedWrap() || Flags.hasNoSignedWrap() ||
-           Flags.hasExact() || Flags.hasDisjoint() || Flags.hasNonNeg() ||
-           Flags.hasNoNaNs() || Flags.hasNoInfs();
+    return Flags.Flags & SDNodeFlags::PoisonGeneratingFlags;
   }
 
   void setCFIType(uint32_t Type) { CFIType = Type; }