DAG: Consider __sincos_stret when deciding to form fsincos (llvm#165169)

Author: arsenm

llvm/include/llvm/CodeGen/RuntimeLibcallUtil.h

@@ -84,6 +84,10 @@ LLVM_ABI Libcall getSINCOS(EVT RetVT);
 /// UNKNOWN_LIBCALL if there is none.
 LLVM_ABI Libcall getSINCOSPI(EVT RetVT);
 
+/// Return the SINCOS_STRET_ value for the given types, or UNKNOWN_LIBCALL if
+/// there is none.
+LLVM_ABI Libcall getSINCOS_STRET(EVT RetVT);
+
 /// getMODF - Return the MODF_* value for the given types, or
 /// UNKNOWN_LIBCALL if there is none.
 LLVM_ABI Libcall getMODF(EVT RetVT);

llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp

@@ -2400,10 +2400,11 @@ SelectionDAGLegalize::ExpandDivRemLibCall(SDNode *Node,
   Results.push_back(Rem);
 }
 
-/// Return true if sincos libcall is available.
+/// Return true if sincos or __sincos_stret libcall is available.
 static bool isSinCosLibcallAvailable(SDNode *Node, const TargetLowering &TLI) {
-  RTLIB::Libcall LC = RTLIB::getSINCOS(Node->getSimpleValueType(0).SimpleTy);
-  return TLI.getLibcallName(LC) != nullptr;
+  MVT::SimpleValueType VT = Node->getSimpleValueType(0).SimpleTy;
+  return TLI.getLibcallImpl(RTLIB::getSINCOS(VT)) != RTLIB::Unsupported ||
+         TLI.getLibcallImpl(RTLIB::getSINCOS_STRET(VT)) != RTLIB::Unsupported;
 }
 
 /// Only issue sincos libcall if both sin and cos are needed.
@@ -3752,9 +3753,9 @@ bool SelectionDAGLegalize::ExpandNode(SDNode *Node) {
     EVT VT = Node->getValueType(0);
     // Turn fsin / fcos into ISD::FSINCOS node if there are a pair of fsin /
     // fcos which share the same operand and both are used.
-    if ((TLI.isOperationLegalOrCustom(ISD::FSINCOS, VT) ||
-         isSinCosLibcallAvailable(Node, TLI))
-        && useSinCos(Node)) {
+    if ((TLI.isOperationLegal(ISD::FSINCOS, VT) ||
+         isSinCosLibcallAvailable(Node, TLI)) &&
+        useSinCos(Node)) {
       SDVTList VTs = DAG.getVTList(VT, VT);
       Tmp1 = DAG.getNode(ISD::FSINCOS, dl, VTs, Node->getOperand(0));
       if (Node->getOpcode() == ISD::FCOS)

llvm/lib/CodeGen/TargetLoweringBase.cpp

@@ -434,6 +434,11 @@ RTLIB::Libcall RTLIB::getSINCOSPI(EVT RetVT) {
                       SINCOSPI_F128, SINCOSPI_PPCF128);
 }
 
+RTLIB::Libcall RTLIB::getSINCOS_STRET(EVT RetVT) {
+  return getFPLibCall(RetVT, SINCOS_STRET_F32, SINCOS_STRET_F64,
+                      UNKNOWN_LIBCALL, UNKNOWN_LIBCALL, UNKNOWN_LIBCALL);
+}
+
 RTLIB::Libcall RTLIB::getMODF(EVT RetVT) {
   return getFPLibCall(RetVT, MODF_F32, MODF_F64, MODF_F80, MODF_F128,
                       MODF_PPCF128);

llvm/lib/Target/ARM/ARMISelLowering.cpp

@@ -1298,12 +1298,8 @@ ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM_,
     setOperationAction(ISD::STRICT_FSETCCS, MVT::f64, Custom);
   }
 
-  // Use __sincos_stret if available.
-  if (getLibcallName(RTLIB::SINCOS_STRET_F32) != nullptr &&
-      getLibcallName(RTLIB::SINCOS_STRET_F64) != nullptr) {
-    setOperationAction(ISD::FSINCOS, MVT::f64, Custom);
-    setOperationAction(ISD::FSINCOS, MVT::f32, Custom);
-  }
+  setOperationAction(ISD::FSINCOS, MVT::f64, Custom);
+  setOperationAction(ISD::FSINCOS, MVT::f32, Custom);
 
   // FP-ARMv8 implements a lot of rounding-like FP operations.
   if (Subtarget->hasFPARMv8Base()) {
@@ -9835,13 +9831,18 @@ static SDValue LowerUADDSUBO_CARRY(SDValue Op, SelectionDAG &DAG) {
 }
 
 SDValue ARMTargetLowering::LowerFSINCOS(SDValue Op, SelectionDAG &DAG) const {
-  assert(Subtarget->isTargetDarwin());
-
   // For iOS, we want to call an alternative entry point: __sincos_stret,
   // return values are passed via sret.
   SDLoc dl(Op);
   SDValue Arg = Op.getOperand(0);
   EVT ArgVT = Arg.getValueType();
+  RTLIB::Libcall LC = RTLIB::getSINCOS_STRET(ArgVT);
+  RTLIB::LibcallImpl SincosStret = getLibcallImpl(LC);
+  if (SincosStret == RTLIB::Unsupported)
+    return SDValue();
+
+  assert(Subtarget->isTargetDarwin());
+
   Type *ArgTy = ArgVT.getTypeForEVT(*DAG.getContext());
   auto PtrVT = getPointerTy(DAG.getDataLayout());
 
@@ -9871,11 +9872,9 @@ SDValue ARMTargetLowering::LowerFSINCOS(SDValue Op, SelectionDAG &DAG) const {
 
   Args.emplace_back(Arg, ArgTy);
 
-  RTLIB::Libcall LC =
-      (ArgVT == MVT::f64) ? RTLIB::SINCOS_STRET_F64 : RTLIB::SINCOS_STRET_F32;
-  const char *LibcallName = getLibcallName(LC);
-  CallingConv::ID CC = getLibcallCallingConv(LC);
-  SDValue Callee = DAG.getExternalSymbol(LibcallName, getPointerTy(DL));
+  StringRef LibcallName = getLibcallImplName(SincosStret);
+  CallingConv::ID CC = getLibcallImplCallingConv(SincosStret);
+  SDValue Callee = DAG.getExternalSymbol(LibcallName.data(), getPointerTy(DL));
 
   TargetLowering::CallLoweringInfo CLI(DAG);
   CLI.setDebugLoc(dl)

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -2572,11 +2572,8 @@ X86TargetLowering::X86TargetLowering(const X86TargetMachine &TM,
   }
 
   // Combine sin / cos into _sincos_stret if it is available.
-  if (getLibcallName(RTLIB::SINCOS_STRET_F32) != nullptr &&
-      getLibcallName(RTLIB::SINCOS_STRET_F64) != nullptr) {
-    setOperationAction(ISD::FSINCOS, MVT::f64, Custom);
-    setOperationAction(ISD::FSINCOS, MVT::f32, Custom);
-  }
+  setOperationAction(ISD::FSINCOS, MVT::f64, Custom);
+  setOperationAction(ISD::FSINCOS, MVT::f32, Custom);
 
   if (Subtarget.isTargetWin64()) {
     setOperationAction(ISD::SDIV, MVT::i128, Custom);
@@ -33067,26 +33064,30 @@ static SDValue LowerADDSUBO_CARRY(SDValue Op, SelectionDAG &DAG) {
 
 static SDValue LowerFSINCOS(SDValue Op, const X86Subtarget &Subtarget,
                             SelectionDAG &DAG) {
+  const TargetLowering &TLI = DAG.getTargetLoweringInfo();
+  SDValue Arg = Op.getOperand(0);
+  EVT ArgVT = Arg.getValueType();
+  bool isF64 = ArgVT == MVT::f64;
+
+  RTLIB::Libcall LC = isF64 ? RTLIB::SINCOS_STRET_F64 : RTLIB::SINCOS_STRET_F32;
+  const char *LibcallName = TLI.getLibcallName(LC);
+  if (!LibcallName)
+    return SDValue();
+
   assert(Subtarget.isTargetDarwin() && Subtarget.is64Bit());
 
   // For MacOSX, we want to call an alternative entry point: __sincos_stret,
   // which returns the values as { float, float } (in XMM0) or
   // { double, double } (which is returned in XMM0, XMM1).
   SDLoc dl(Op);
-  SDValue Arg = Op.getOperand(0);
-  EVT ArgVT = Arg.getValueType();
   Type *ArgTy = ArgVT.getTypeForEVT(*DAG.getContext());
 
   TargetLowering::ArgListTy Args;
   Args.emplace_back(Arg, ArgTy);
 
-  bool isF64 = ArgVT == MVT::f64;
   // Only optimize x86_64 for now. i386 is a bit messy. For f32,
   // the small struct {f32, f32} is returned in (eax, edx). For f64,
   // the results are returned via SRet in memory.
-  const TargetLowering &TLI = DAG.getTargetLoweringInfo();
-  RTLIB::Libcall LC = isF64 ? RTLIB::SINCOS_STRET_F64 : RTLIB::SINCOS_STRET_F32;
-  const char *LibcallName = TLI.getLibcallName(LC);
   SDValue Callee =
       DAG.getExternalSymbol(LibcallName, TLI.getPointerTy(DAG.getDataLayout()));