Fix code styles

1. Use Op.getConstantOperandVal to get Constant value
2. (NoFPClass & fcNan) == fcNan
3. Use N2->getAsZExtValue() to get Constant value
4. Use getTargetConstant with ptr width to fix 32bit target
5. Don't propagate the flags
6. Add MIPSr6 testcase for 32bit target tests

Author: Your Name

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

@@ -5761,13 +5761,11 @@ bool SelectionDAG::isKnownNeverNaN(SDValue Op, const APInt &DemandedElts,
     return true;
   }
   case ISD::AssertNoFPClass: {
-    SDValue SDNoFPClass = Op.getOperand(1);
-    assert(isa<ConstantSDNode>(SDNoFPClass) && "NoFPClass is not Constant");
-    FPClassTest NoFPClass = static_cast<FPClassTest>(
-        dyn_cast<ConstantSDNode>(SDNoFPClass)->getZExtValue());
-    if (NoFPClass & fcNan)
+    FPClassTest NoFPClass =
+        static_cast<FPClassTest>(Op.getConstantOperandVal(1));
+    if ((NoFPClass & fcNan) == fcNan)
       return true;
-    if (SNaN && (NoFPClass & fcSNan))
+    if (SNaN && (NoFPClass & fcSNan) == fcSNan)
       return true;
     return isKnownNeverNaN(Op.getOperand(0), SNaN, Depth + 1);
   }
@@ -7421,8 +7419,7 @@ SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
     assert(N1.getValueType().isFloatingPoint() &&
            "AssertNoFPClass is used for a non-floating type");
     assert(isa<ConstantSDNode>(N2) && "NoFPClass is not Constant");
-    FPClassTest NoFPClass =
-        static_cast<FPClassTest>(dyn_cast<ConstantSDNode>(N2)->getZExtValue());
+    FPClassTest NoFPClass = static_cast<FPClassTest>(N2->getAsZExtVal());
     assert(llvm::to_underlying(NoFPClass) <=
                BitmaskEnumDetail::Mask<FPClassTest>() &&
            "FPClassTest value too large");

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -11850,12 +11850,11 @@ void SelectionDAGISel::LowerArguments(const Function &F) {
 
     FPClassTest NoFPClass = Arg.getNoFPClass();
     if (NoFPClass != fcNone) {
-      EVT I64EVT = EVT::getIntegerVT(*DAG.getContext(), 64);
       SDValue SDNoFPClass =
-          DAG.getConstant(static_cast<uint64_t>(NoFPClass), dl, I64EVT);
-      SDNodeFlags ResFlags = Res->getFlags();
+          DAG.getTargetConstant(static_cast<uint64_t>(NoFPClass), dl,
+                                TLI->getPointerTy(DAG.getDataLayout()));
       Res = DAG.getNode(ISD::AssertNoFPClass, dl, Res.getValueType(), Res,
-                        SDNoFPClass, ResFlags);
+                        SDNoFPClass);
     }
 
     SDB->setValue(&Arg, Res);

llvm/test/CodeGen/Mips/nofpclass.ll

@@ -0,0 +1,18 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc --mtriple=mipsisa32r6-linux-gnu < %s | FileCheck %s --check-prefix=MIPS32R6
+; RUN: llc --mtriple=mipsisa64r6-linux-gnu < %s | FileCheck %s --check-prefix=MIPS64R6
+
+define nofpclass(nzero) float @f(float nofpclass(nan) %a, float nofpclass(nan) %b) {
+; MIPS32R6-LABEL: f:
+; MIPS32R6:       # %bb.0: # %entry
+; MIPS32R6-NEXT:    jr $ra
+; MIPS32R6-NEXT:    max.s $f0, $f12, $f14
+;
+; MIPS64R6-LABEL: f:
+; MIPS64R6:       # %bb.0: # %entry
+; MIPS64R6-NEXT:    jr $ra
+; MIPS64R6-NEXT:    max.s $f0, $f12, $f13
+entry:
+  %cond = tail call float @llvm.maximumnum.f32(float %a, float %b)
+  ret float %cond
+}