SelectionDAG: Support nofpclass(nan/qnan/snan)

SelectionDAGISel::LowerArguments: Pass NoNaN Flags to InVals.

`nofpclass` support values nan, snan, qnan, where nan=snan|qnan.
So let's use NoSNaNs and NoQNaNs in SDNodeFlags.

Thus, we can use it in isKnownNeverNaN.

Author: wzssyqa

llvm/include/llvm/CodeGen/SelectionDAGNodes.h

@@ -397,7 +397,7 @@ struct SDNodeFlags {
     Exact = 1 << 2,
     Disjoint = 1 << 3,
     NonNeg = 1 << 4,
-    NoNaNs = 1 << 5,
+    // 1 << 5 was used as NoNaNs
     NoInfs = 1 << 6,
     NoSignedZeros = 1 << 7,
     AllowReciprocal = 1 << 8,
@@ -416,21 +416,26 @@ struct SDNodeFlags {
     // Compare instructions which may carry the samesign flag.
     SameSign = 1 << 14,
 
+    NoSNaNs = 1 << 15,
+    NoQNaNs = 1 << 16,
+
     // 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 | SameSign,
-    FastMathFlags = NoNaNs | NoInfs | NoSignedZeros | AllowReciprocal |
-                    AllowContract | ApproximateFuncs | AllowReassociation,
+                            NonNeg | NoSNaNs | NoQNaNs | NoInfs | SameSign,
+    FastMathFlags = NoSNaNs | NoQNaNs | NoInfs | NoSignedZeros |
+                    AllowReciprocal | AllowContract | ApproximateFuncs |
+                    AllowReassociation,
   };
 
   /// Default constructor turns off all optimization flags.
   SDNodeFlags(unsigned Flags = SDNodeFlags::None) : Flags(Flags) {}
 
   /// Propagate the fast-math-flags from an IR FPMathOperator.
   void copyFMF(const FPMathOperator &FPMO) {
-    setNoNaNs(FPMO.hasNoNaNs());
+    setNoSNaNs(FPMO.hasNoNaNs());
+    setNoQNaNs(FPMO.hasNoNaNs());
     setNoInfs(FPMO.hasNoInfs());
     setNoSignedZeros(FPMO.hasNoSignedZeros());
     setAllowReciprocal(FPMO.hasAllowReciprocal());
@@ -446,7 +451,12 @@ struct SDNodeFlags {
   void setDisjoint(bool b) { setFlag<Disjoint>(b); }
   void setSameSign(bool b) { setFlag<SameSign>(b); }
   void setNonNeg(bool b) { setFlag<NonNeg>(b); }
-  void setNoNaNs(bool b) { setFlag<NoNaNs>(b); }
+  void setNoNaNs(bool b) {
+    setFlag<NoSNaNs>(b);
+    setFlag<NoQNaNs>(b);
+  }
+  void setNoSNaNs(bool b) { setFlag<NoSNaNs>(b); }
+  void setNoQNaNs(bool b) { setFlag<NoQNaNs>(b); }
   void setNoInfs(bool b) { setFlag<NoInfs>(b); }
   void setNoSignedZeros(bool b) { setFlag<NoSignedZeros>(b); }
   void setAllowReciprocal(bool b) { setFlag<AllowReciprocal>(b); }
@@ -463,7 +473,9 @@ struct SDNodeFlags {
   bool hasDisjoint() const { return Flags & Disjoint; }
   bool hasSameSign() const { return Flags & SameSign; }
   bool hasNonNeg() const { return Flags & NonNeg; }
-  bool hasNoNaNs() const { return Flags & NoNaNs; }
+  bool hasNoNaNs() const { return (Flags & NoSNaNs) && (Flags & NoQNaNs); }
+  bool hasNoSNaNs() const { return Flags & NoSNaNs; }
+  bool hasNoQNaNs() const { return Flags & NoQNaNs; }
   bool hasNoInfs() const { return Flags & NoInfs; }
   bool hasNoSignedZeros() const { return Flags & NoSignedZeros; }
   bool hasAllowReciprocal() const { return Flags & AllowReciprocal; }

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

@@ -5613,7 +5613,12 @@ bool SelectionDAG::isBaseWithConstantOffset(SDValue Op) const {
 
 bool SelectionDAG::isKnownNeverNaN(SDValue Op, bool SNaN, unsigned Depth) const {
   // If we're told that NaNs won't happen, assume they won't.
-  if (getTarget().Options.NoNaNsFPMath || Op->getFlags().hasNoNaNs())
+  if (getTarget().Options.NoNaNsFPMath)
+    return true;
+  SDNodeFlags OpFlags = Op->getFlags();
+  if (SNaN && OpFlags.hasNoSNaNs())
+    return true;
+  if (OpFlags.hasNoSNaNs() && OpFlags.hasNoQNaNs())
     return true;
 
   if (Depth >= MaxRecursionDepth)

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -11891,6 +11891,16 @@ void SelectionDAGISel::LowerArguments(const Function &F) {
           AssertOp = ISD::AssertSext;
         else if (Arg.hasAttribute(Attribute::ZExt))
           AssertOp = ISD::AssertZext;
+        if (Arg.hasAttribute(Attribute::NoFPClass)) {
+          SDNodeFlags InValFlags = InVals[i]->getFlags();
+          bool NoSNaN = ((Arg.getNoFPClass() & llvm::fcSNan) == llvm::fcSNan);
+          bool NoQNaN = ((Arg.getNoFPClass() & llvm::fcQNan) == llvm::fcQNan);
+          InValFlags.setNoSNaNs(NoSNaN);
+          InValFlags.setNoQNaNs(NoQNaN);
+          InValFlags.setNoInfs((Arg.getNoFPClass() & llvm::fcInf) ==
+                               llvm::fcInf);
+          InVals[i]->setFlags(InValFlags);
+        }
 
         ArgValues.push_back(getCopyFromParts(DAG, dl, &InVals[i], NumParts,
                                              PartVT, VT, nullptr, NewRoot,