expandFMINIMUMNUM_FMAXIMUMNUM: Quiet is not needed for NaN vs NaN

New LangRef doesn't requires quieting for NaN vs NaN, aka
the result may be sNaN for sNaN vs NaN.
See: llvm#139228

Author: wzssyqa

llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -8684,11 +8684,6 @@ SDValue TargetLowering::expandFMINIMUMNUM_FMAXIMUMNUM(SDNode *Node,
 
   SDValue MinMax =
       DAG.getSelectCC(DL, LHS, RHS, LHS, RHS, IsMax ? ISD::SETGT : ISD::SETLT);
-  // If MinMax is NaN, let's quiet it.
-  if (!Flags.hasNoNaNs() && !DAG.isKnownNeverNaN(LHS) &&
-      !DAG.isKnownNeverNaN(RHS)) {
-    MinMax = DAG.getNode(ISD::FCANONICALIZE, DL, VT, MinMax, Flags);
-  }
 
   // Fixup signed zero behavior.
   if (Options.NoSignedZerosFPMath || Flags.hasNoSignedZeros() ||