[NVPTX] legalize v2i32 to improve codegen of v2f32 ops

Since v2f32 is legal but v2i32 is not, this causes some sequences of
operations like bitcast (build_vector) to be lowered inefficiently.

Author: Prince781

llvm/lib/Target/NVPTX/NVPTXISelDAGToDAG.cpp

@@ -1018,6 +1018,7 @@ pickOpcodeForVT(MVT::SimpleValueType VT, std::optional<unsigned> Opcode_i16,
   case MVT::f32:
     return Opcode_i32;
   case MVT::v2f32:
+  case MVT::v2i32:
   case MVT::i64:
   case MVT::f64:
     return Opcode_i64;

llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp

@@ -226,21 +226,20 @@ getVectorLoweringShape(EVT VectorEVT, const NVPTXSubtarget &STI,
   switch (VectorVT.SimpleTy) {
   default:
     return std::nullopt;
+
   case MVT::v4i64:
   case MVT::v4f64:
-  case MVT::v8i32:
-    // This is a "native" vector type iff the address space is global
-    // and the target supports 256-bit loads/stores
+    // This is a "native" vector type iff the address space is global and the
+    // target supports 256-bit loads/stores
     if (!CanLowerTo256Bit)
       return std::nullopt;
     LLVM_FALLTHROUGH;
   case MVT::v2i8:
-  case MVT::v2i32:
   case MVT::v2i64:
   case MVT::v2f64:
-  case MVT::v4i32:
     // This is a "native" vector type
     return std::pair(NumElts, EltVT);
+
   case MVT::v16f16:  // <8 x f16x2>
   case MVT::v16bf16: // <8 x bf16x2>
   case MVT::v16i16:  // <8 x i16x2>
@@ -264,12 +263,18 @@ getVectorLoweringShape(EVT VectorEVT, const NVPTXSubtarget &STI,
   case MVT::v16i8:  // <4 x i8x4>
     PackRegSize = 32;
     break;
-  case MVT::v8f32: // <4 x f32x2>
+
+  case MVT::v8f32:  // <4 x f32x2>
+  case MVT::v8i32:  // <4 x i32x2>
+    // This is a "native" vector type iff the address space is global and the
+    // target supports 256-bit loads/stores
     if (!CanLowerTo256Bit)
       return std::nullopt;
     LLVM_FALLTHROUGH;
-  case MVT::v2f32: // <1 x f32x2>
-  case MVT::v4f32: // <2 x f32x2>
+  case MVT::v2f32:  // <1 x f32x2>
+  case MVT::v4f32:  // <2 x f32x2>
+  case MVT::v2i32:  // <1 x i32x2>
+  case MVT::v4i32:  // <2 x i32x2>
     if (!STI.hasF32x2Instructions())
       return std::pair(NumElts, EltVT);
     PackRegSize = 64;
@@ -590,8 +595,10 @@ NVPTXTargetLowering::NVPTXTargetLowering(const NVPTXTargetMachine &TM,
   addRegisterClass(MVT::bf16, &NVPTX::B16RegClass);
   addRegisterClass(MVT::v2bf16, &NVPTX::B32RegClass);
 
-  if (STI.hasF32x2Instructions())
+  if (STI.hasF32x2Instructions()) {
     addRegisterClass(MVT::v2f32, &NVPTX::B64RegClass);
+    addRegisterClass(MVT::v2i32, &NVPTX::B64RegClass);
+  }
 
   // Conversion to/from FP16/FP16x2 is always legal.
   setOperationAction(ISD::BUILD_VECTOR, MVT::v2f16, Custom);
@@ -628,12 +635,13 @@ NVPTXTargetLowering::NVPTXTargetLowering(const NVPTXTargetMachine &TM,
   setOperationAction(ISD::INSERT_VECTOR_ELT, MVT::v4i8, Custom);
   setOperationAction(ISD::VECTOR_SHUFFLE, MVT::v4i8, Custom);
 
-  // No support for these operations with v2f32.
-  setOperationAction(ISD::INSERT_VECTOR_ELT, MVT::v2f32, Expand);
-  setOperationAction(ISD::VECTOR_SHUFFLE, MVT::v2f32, Expand);
+  // No support for these operations with v2f32/v2i32
+  setOperationAction(ISD::INSERT_VECTOR_ELT, {MVT::v2f32, MVT::v2i32}, Expand);
+  setOperationAction(ISD::VECTOR_SHUFFLE, {MVT::v2f32, MVT::v2i32}, Expand);
   // Need custom lowering in case the index is dynamic.
   if (STI.hasF32x2Instructions())
-    setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::v2f32, Custom);
+    setOperationAction(ISD::EXTRACT_VECTOR_ELT, {MVT::v2f32, MVT::v2i32},
+                       Custom);
 
   // Custom conversions to/from v2i8.
   setOperationAction(ISD::BITCAST, MVT::v2i8, Custom);
@@ -661,14 +669,13 @@ NVPTXTargetLowering::NVPTXTargetLowering(const NVPTXTargetMachine &TM,
   // Operations not directly supported by NVPTX.
   for (MVT VT : {MVT::bf16, MVT::f16, MVT::v2bf16, MVT::v2f16, MVT::f32,
                  MVT::v2f32, MVT::f64, MVT::i1, MVT::i8, MVT::i16, MVT::v2i16,
-                 MVT::v4i8, MVT::i32, MVT::i64}) {
+                 MVT::v4i8, MVT::i32, MVT::v2i32, MVT::i64}) {
     setOperationAction(ISD::SELECT_CC, VT, Expand);
     setOperationAction(ISD::BR_CC, VT, Expand);
   }
 
-  // Not directly supported. TLI would attempt to expand operations like
-  // FMINIMUM(v2f32) using invalid SETCC and VSELECT nodes.
-  setOperationAction(ISD::VSELECT, MVT::v2f32, Expand);
+  // We don't want ops like FMINIMUM or UMAX to be lowered to SETCC+VSELECT.
+  setOperationAction(ISD::VSELECT, {MVT::v2f32, MVT::v2i32}, Expand);
 
   // Some SIGN_EXTEND_INREG can be done using cvt instruction.
   // For others we will expand to a SHL/SRA pair.
@@ -815,7 +822,14 @@ NVPTXTargetLowering::NVPTXTargetLowering(const NVPTXTargetMachine &TM,
   setOperationAction({ISD::SDIV, ISD::UDIV, ISD::SRA, ISD::SRL, ISD::MULHS,
                       ISD::MULHU, ISD::FP_TO_SINT, ISD::FP_TO_UINT,
                       ISD::SINT_TO_FP, ISD::UINT_TO_FP, ISD::SETCC},
-                     MVT::v2i16, Expand);
+                     {MVT::v2i16, MVT::v2i32}, Expand);
+
+  // v2i32 is not supported for any arithmetic operations
+  setOperationAction({ISD::ABS, ISD::SMIN, ISD::SMAX, ISD::UMIN, ISD::UMAX,
+                      ISD::CTPOP, ISD::CTLZ, ISD::ADD, ISD::SUB, ISD::MUL,
+                      ISD::SHL, ISD::SRA, ISD::SRL, ISD::OR, ISD::AND, ISD::XOR,
+                      ISD::SREM, ISD::UREM},
+                     MVT::v2i32, Expand);
 
   setOperationAction(ISD::ADDC, MVT::i32, Legal);
   setOperationAction(ISD::ADDE, MVT::i32, Legal);
@@ -829,7 +843,7 @@ NVPTXTargetLowering::NVPTXTargetLowering(const NVPTXTargetMachine &TM,
   }
 
   setOperationAction(ISD::CTTZ, MVT::i16, Expand);
-  setOperationAction(ISD::CTTZ, MVT::v2i16, Expand);
+  setOperationAction(ISD::CTTZ, {MVT::v2i16, MVT::v2i32}, Expand);
   setOperationAction(ISD::CTTZ, MVT::i32, Expand);
   setOperationAction(ISD::CTTZ, MVT::i64, Expand);
 
@@ -1067,7 +1081,7 @@ NVPTXTargetLowering::NVPTXTargetLowering(const NVPTXTargetMachine &TM,
   // Custom lowering for tcgen05.st vector operands
   setOperationAction(ISD::INTRINSIC_VOID,
                      {MVT::v2i32, MVT::v4i32, MVT::v8i32, MVT::v16i32,
-                      MVT::v32i32, MVT::v64i32, MVT::v128i32},
+                      MVT::v32i32, MVT::v64i32, MVT::v128i32, MVT::Other},
                      Custom);
 
   // Enable custom lowering for the following:
@@ -2572,7 +2586,7 @@ static SDValue LowerVectorArith(SDValue Op, SelectionDAG &DAG) {
   return V;
 }
 
-static SDValue LowerTcgen05St(SDValue Op, SelectionDAG &DAG) {
+static SDValue lowerTcgen05St(SDValue Op, SelectionDAG &DAG) {
   SDNode *N = Op.getNode();
   SDLoc DL(N);
   SmallVector<SDValue, 32> Ops;
@@ -2598,7 +2612,52 @@ static SDValue LowerTcgen05St(SDValue Op, SelectionDAG &DAG) {
   return Tcgen05StNode;
 }
 
-static SDValue LowerIntrinsicVoid(SDValue Op, SelectionDAG &DAG) {
+// Lower vector return type of tcgen05.ld intrinsics
+static std::optional<std::pair<SDValue, SDValue>>
+lowerTcgen05Ld(SDNode *N, SelectionDAG &DAG, bool HasOffset = false) {
+  SDLoc DL(N);
+  EVT ResVT = N->getValueType(0);
+  if (!ResVT.isVector())
+    return {}; // already legalized.
+
+  const unsigned NumElts = ResVT.getVectorNumElements();
+
+  // Create the return type of the instructions
+  SmallVector<EVT, 5> ListVTs;
+  for (unsigned i = 0; i < NumElts; ++i)
+    ListVTs.push_back(MVT::i32);
+
+  ListVTs.push_back(N->getValueType(1)); // Chain
+
+  SDVTList ResVTs = DAG.getVTList(ListVTs);
+
+  SmallVector<SDValue, 8> Ops{N->getOperand(0), N->getOperand(1),
+                              N->getOperand(2)};
+
+  if (HasOffset) {
+    Ops.push_back(N->getOperand(3)); // offset
+    Ops.push_back(N->getOperand(4)); // Pack flag
+  } else
+    Ops.push_back(N->getOperand(3)); // Pack flag
+
+  MemIntrinsicSDNode *MemSD = cast<MemIntrinsicSDNode>(N);
+  SDValue NewNode =
+      DAG.getMemIntrinsicNode(ISD::INTRINSIC_W_CHAIN, DL, ResVTs, Ops,
+                              MemSD->getMemoryVT(), MemSD->getMemOperand());
+
+  // split the vector result
+  SmallVector<SDValue, 4> ScalarRes;
+  for (unsigned i = 0; i < NumElts; ++i) {
+    SDValue Res = NewNode.getValue(i);
+    ScalarRes.push_back(Res);
+  }
+
+  SDValue Chain = NewNode.getValue(NumElts);
+  SDValue BuildVector = DAG.getNode(ISD::BUILD_VECTOR, DL, ResVT, ScalarRes);
+  return {{BuildVector, Chain}};
+}
+
+static SDValue lowerIntrinsicVoid(SDValue Op, SelectionDAG &DAG) {
   SDNode *N = Op.getNode();
   SDValue Intrin = N->getOperand(1);
 
@@ -2644,7 +2703,7 @@ static SDValue LowerIntrinsicVoid(SDValue Op, SelectionDAG &DAG) {
   case Intrinsic::nvvm_tcgen05_st_16x64b_x64:
   case Intrinsic::nvvm_tcgen05_st_32x32b_x64:
   case Intrinsic::nvvm_tcgen05_st_32x32b_x128:
-    return LowerTcgen05St(Op, DAG);
+    return lowerTcgen05St(Op, DAG);
   }
   return Op;
 }
@@ -2717,6 +2776,26 @@ static SDValue lowerPrmtIntrinsic(SDValue Op, SelectionDAG &DAG) {
   SDValue Selector = (Op->op_end() - 1)->get();
   return getPRMT(A, B, Selector, DL, DAG, Mode);
 }
+
+static SDValue lowerIntrinsicWChain(SDValue Op, SelectionDAG &DAG) {
+  switch (Op->getConstantOperandVal(1)) {
+  default:
+    return Op;
+
+  case Intrinsic::nvvm_tcgen05_ld_16x64b_x2:
+  case Intrinsic::nvvm_tcgen05_ld_16x128b_x1:
+  case Intrinsic::nvvm_tcgen05_ld_32x32b_x2:
+    if (auto Pair = lowerTcgen05Ld(Op.getNode(), DAG))
+      return DAG.getMergeValues({Pair->first, Pair->second}, SDLoc(Op));
+    return SDValue();
+
+  case Intrinsic::nvvm_tcgen05_ld_16x32bx2_x2:
+    if (auto Pair = lowerTcgen05Ld(Op.getNode(), DAG, /*HasOffset=*/true))
+      return DAG.getMergeValues({Pair->first, Pair->second}, SDLoc(Op));
+    return SDValue();
+  }
+}
+
 static SDValue lowerIntrinsicWOChain(SDValue Op, SelectionDAG &DAG) {
   switch (Op->getConstantOperandVal(0)) {
   default:
@@ -2879,11 +2958,11 @@ NVPTXTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::ADDRSPACECAST:
     return LowerADDRSPACECAST(Op, DAG);
   case ISD::INTRINSIC_W_CHAIN:
-    return Op;
+    return lowerIntrinsicWChain(Op, DAG);
   case ISD::INTRINSIC_WO_CHAIN:
     return lowerIntrinsicWOChain(Op, DAG);
   case ISD::INTRINSIC_VOID:
-    return LowerIntrinsicVoid(Op, DAG);
+    return lowerIntrinsicVoid(Op, DAG);
   case ISD::BUILD_VECTOR:
     return LowerBUILD_VECTOR(Op, DAG);
   case ISD::BITCAST:
@@ -5673,7 +5752,7 @@ static SDValue PerformEXTRACTCombine(SDNode *N,
       IsPTXVectorType(VectorVT.getSimpleVT()))
     return SDValue(); // Native vector loads already combine nicely w/
                       // extract_vector_elt.
-  // Don't mess with singletons or packed types (v2f32, v2*16, v4i8 and v8i8),
+  // Don't mess with singletons or packed types (v2*32, v2*16, v4i8 and v8i8),
   // we already handle them OK.
   if (VectorVT.getVectorNumElements() == 1 ||
       NVPTX::isPackedVectorTy(VectorVT) || VectorVT == MVT::v8i8)
@@ -6045,53 +6124,6 @@ static void ReplaceBITCAST(SDNode *Node, SelectionDAG &DAG,
       DAG.getNode(ISD::BUILD_VECTOR, DL, MVT::v2i8, {Vec0, Vec1}));
 }
 
-// Lower vector return type of tcgen05.ld intrinsics
-static void ReplaceTcgen05Ld(SDNode *N, SelectionDAG &DAG,
-                             SmallVectorImpl<SDValue> &Results,
-                             bool hasOffset = false) {
-  SDLoc DL(N);
-  EVT ResVT = N->getValueType(0);
-  if (!ResVT.isVector())
-    return; // already legalized.
-
-  const unsigned NumElts = ResVT.getVectorNumElements();
-
-  // Create the return type of the instructions
-  SmallVector<EVT, 5> ListVTs;
-  for (unsigned i = 0; i < NumElts; ++i)
-    ListVTs.push_back(MVT::i32);
-
-  ListVTs.push_back(N->getValueType(1)); // Chain
-
-  SDVTList ResVTs = DAG.getVTList(ListVTs);
-
-  SmallVector<SDValue, 8> Ops{N->getOperand(0), N->getOperand(1),
-                              N->getOperand(2)};
-
-  if (hasOffset) {
-    Ops.push_back(N->getOperand(3)); // offset
-    Ops.push_back(N->getOperand(4)); // Pack flag
-  } else
-    Ops.push_back(N->getOperand(3)); // Pack flag
-
-  MemIntrinsicSDNode *MemSD = cast<MemIntrinsicSDNode>(N);
-  SDValue NewNode =
-      DAG.getMemIntrinsicNode(ISD::INTRINSIC_W_CHAIN, DL, ResVTs, Ops,
-                              MemSD->getMemoryVT(), MemSD->getMemOperand());
-
-  // split the vector result
-  SmallVector<SDValue, 4> ScalarRes;
-  for (unsigned i = 0; i < NumElts; ++i) {
-    SDValue Res = NewNode.getValue(i);
-    ScalarRes.push_back(Res);
-  }
-
-  SDValue Chain = NewNode.getValue(NumElts);
-  SDValue BuildVector = DAG.getNode(ISD::BUILD_VECTOR, DL, ResVT, ScalarRes);
-  Results.push_back(BuildVector); // Build Vector
-  Results.push_back(Chain);       // Chain
-}
-
 static void ReplaceINTRINSIC_W_CHAIN(SDNode *N, SelectionDAG &DAG,
                                      SmallVectorImpl<SDValue> &Results) {
   SDValue Chain = N->getOperand(0);
@@ -6227,7 +6259,11 @@ static void ReplaceINTRINSIC_W_CHAIN(SDNode *N, SelectionDAG &DAG,
   case Intrinsic::nvvm_tcgen05_ld_16x256b_x8:
   case Intrinsic::nvvm_tcgen05_ld_16x256b_x16:
   case Intrinsic::nvvm_tcgen05_ld_16x256b_x32:
-    return ReplaceTcgen05Ld(N, DAG, Results);
+    if (auto Pair = lowerTcgen05Ld(N, DAG)) {
+      Results.push_back(Pair->first);
+      Results.push_back(Pair->second);
+    }
+    return;
 
   case Intrinsic::nvvm_tcgen05_ld_16x32bx2_x2:
   case Intrinsic::nvvm_tcgen05_ld_16x32bx2_x4:
@@ -6236,7 +6272,11 @@ static void ReplaceINTRINSIC_W_CHAIN(SDNode *N, SelectionDAG &DAG,
   case Intrinsic::nvvm_tcgen05_ld_16x32bx2_x32:
   case Intrinsic::nvvm_tcgen05_ld_16x32bx2_x64:
   case Intrinsic::nvvm_tcgen05_ld_16x32bx2_x128:
-    return ReplaceTcgen05Ld(N, DAG, Results, /* Offset */ true);
+    if (auto Pair = lowerTcgen05Ld(N, DAG, /*HasOffset=*/true)) {
+      Results.push_back(Pair->first);
+      Results.push_back(Pair->second);
+    }
+    return;
   }
 }
 

llvm/lib/Target/NVPTX/NVPTXInstrInfo.td

@@ -754,8 +754,10 @@ def : Pat<(vt (select i1:$p, vt:$a, vt:$b)),
           (SELP_b32rr $a, $b, $p)>;
 }
 
-def : Pat<(v2f32 (select i1:$p, v2f32:$a, v2f32:$b)),
+foreach vt = [v2f32, v2i32] in {
+def : Pat<(vt (select i1:$p, vt:$a, vt:$b)),
           (SELP_b64rr $a, $b, $p)>;
+}
 
 //-----------------------------------
 // Test Instructions
@@ -2092,8 +2094,8 @@ foreach vt = [v2f16, v2bf16, v2i16] in {
             (V2I16toI32 $a, $b)>;
 }
 
-// Same thing for the 64-bit type v2f32.
-foreach vt = [v2f32] in {
+// Handle extracting one element from the pair (64-bit types)
+foreach vt = [v2f32, v2i32] in {
   def : Pat<(extractelt vt:$src, 0), (I64toI32L_Sink $src)>, Requires<[hasPTX<71>]>;
   def : Pat<(extractelt vt:$src, 1), (I64toI32H_Sink $src)>, Requires<[hasPTX<71>]>;
 

llvm/lib/Target/NVPTX/NVPTXRegisterInfo.td

@@ -54,7 +54,8 @@ def B16 : NVPTXRegClass<[i16, f16, bf16], 16, (add (sequence "RS%u", 0, 4))>;
 def B32 : NVPTXRegClass<[i32, v2f16, v2bf16, v2i16, v4i8, f32], 32,
                               (add (sequence "R%u", 0, 4),
                               VRFrame32, VRFrameLocal32)>;
-def B64 : NVPTXRegClass<[i64, v2f32, f64], 64, (add (sequence "RL%u", 0, 4),
+def B64 : NVPTXRegClass<[i64, v2i32, v2f32, f64], 64,
+                        (add (sequence "RL%u", 0, 4),
                          VRFrame64, VRFrameLocal64)>;
 // 128-bit regs are not defined as general regs in NVPTX. They are used for inlineASM only.
 def B128 : NVPTXRegClass<[i128], 128, (add (sequence "RQ%u", 0, 4))>;

llvm/lib/Target/NVPTX/NVPTXUtilities.h

@@ -99,8 +99,8 @@ namespace NVPTX {
 // register. NOTE: This must be kept in sync with the register classes
 // defined in NVPTXRegisterInfo.td.
 inline auto packed_types() {
-  static const auto PackedTypes = {MVT::v4i8, MVT::v2f16, MVT::v2bf16,
-                                   MVT::v2i16, MVT::v2f32};
+  static const auto PackedTypes = {MVT::v4i8,  MVT::v2f16, MVT::v2bf16,
+                                   MVT::v2i16, MVT::v2f32, MVT::v2i32};
   return PackedTypes;
 }