[SelectionDAG] Only handle arch-specific COPYSIGNs as libcalls

Author: workingjubilee

llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp

@@ -1649,12 +1649,13 @@ void DAGTypeLegalizer::ExpandFloatRes_FCEIL(SDNode *N,
 
 void DAGTypeLegalizer::ExpandFloatRes_FCOPYSIGN(SDNode *N,
                                                 SDValue &Lo, SDValue &Hi) {
-  ExpandFloatRes_Binary(N, GetFPLibCall(N->getValueType(0),
-                                        RTLIB::COPYSIGN_F32,
-                                        RTLIB::COPYSIGN_F64,
-                                        RTLIB::COPYSIGN_F80,
-                                        RTLIB::COPYSIGN_F128,
-                                        RTLIB::COPYSIGN_PPCF128), Lo, Hi);
+
+  auto VT = N->getValueType(0);
+  ExpandFloatRes_Binary(N,
+                        (VT == MVT::f80       ? RTLIB::COPYSIGN_F80
+                         : VT == MVT::ppcf128 ? RTLIB::COPYSIGN_PPCF128
+                                              : RTLIB::UNKNOWN_LIBCALL),
+                        Lo, Hi);
 }
 
 void DAGTypeLegalizer::ExpandFloatRes_FCOS(SDNode *N,