LegalizeTypesGeneric.cpp revision 475871a144eb604ddaf37503397ba0941442e5fb
1//===-------- LegalizeTypesGeneric.cpp - Generic type legalization --------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements generic type expansion and splitting for LegalizeTypes. 11// The routines here perform legalization when the details of the type (such as 12// whether it is an integer or a float) do not matter. 13// Expansion is the act of changing a computation in an illegal type to be a 14// computation in two identical registers of a smaller type. 15// Splitting is the act of changing a computation in an illegal type to be a 16// computation in two not necessarily identical registers of a smaller type. 17// 18//===----------------------------------------------------------------------===// 19 20#include "LegalizeTypes.h" 21using namespace llvm; 22 23//===----------------------------------------------------------------------===// 24// Generic Result Expansion. 25//===----------------------------------------------------------------------===// 26 27// These routines assume that the Lo/Hi part is stored first in memory on 28// little/big-endian machines, followed by the Hi/Lo part. This means that 29// they cannot be used as is on vectors, for which Lo is always stored first. 30 31void DAGTypeLegalizer::ExpandRes_BIT_CONVERT(SDNode *N, SDValue &Lo, 32 SDValue &Hi) { 33 MVT NVT = TLI.getTypeToTransformTo(N->getValueType(0)); 34 SDValue InOp = N->getOperand(0); 35 MVT InVT = InOp.getValueType(); 36 37 // Handle some special cases efficiently. 38 switch (getTypeAction(InVT)) { 39 default: 40 assert(false && "Unknown type action!"); 41 case Legal: 42 case PromoteInteger: 43 break; 44 case SoftenFloat: 45 // Convert the integer operand instead. 46 SplitInteger(GetSoftenedFloat(InOp), Lo, Hi); 47 Lo = DAG.getNode(ISD::BIT_CONVERT, NVT, Lo); 48 Hi = DAG.getNode(ISD::BIT_CONVERT, NVT, Hi); 49 return; 50 case ExpandInteger: 51 case ExpandFloat: 52 // Convert the expanded pieces of the input. 53 GetExpandedOp(InOp, Lo, Hi); 54 Lo = DAG.getNode(ISD::BIT_CONVERT, NVT, Lo); 55 Hi = DAG.getNode(ISD::BIT_CONVERT, NVT, Hi); 56 return; 57 case SplitVector: 58 // Convert the split parts of the input if it was split in two. 59 GetSplitVector(InOp, Lo, Hi); 60 if (Lo.getValueType() == Hi.getValueType()) { 61 if (TLI.isBigEndian()) 62 std::swap(Lo, Hi); 63 Lo = DAG.getNode(ISD::BIT_CONVERT, NVT, Lo); 64 Hi = DAG.getNode(ISD::BIT_CONVERT, NVT, Hi); 65 return; 66 } 67 break; 68 case ScalarizeVector: 69 // Convert the element instead. 70 SplitInteger(BitConvertToInteger(GetScalarizedVector(InOp)), Lo, Hi); 71 Lo = DAG.getNode(ISD::BIT_CONVERT, NVT, Lo); 72 Hi = DAG.getNode(ISD::BIT_CONVERT, NVT, Hi); 73 return; 74 } 75 76 // Lower the bit-convert to a store/load from the stack, then expand the load. 77 SDValue Op = CreateStackStoreLoad(InOp, N->getValueType(0)); 78 ExpandRes_NormalLoad(Op.Val, Lo, Hi); 79} 80 81void DAGTypeLegalizer::ExpandRes_BUILD_PAIR(SDNode *N, SDValue &Lo, 82 SDValue &Hi) { 83 // Return the operands. 84 Lo = N->getOperand(0); 85 Hi = N->getOperand(1); 86} 87 88void DAGTypeLegalizer::ExpandRes_EXTRACT_ELEMENT(SDNode *N, SDValue &Lo, 89 SDValue &Hi) { 90 GetExpandedOp(N->getOperand(0), Lo, Hi); 91 SDValue Part = cast<ConstantSDNode>(N->getOperand(1))->getValue() ? Hi : Lo; 92 93 assert(Part.getValueType() == N->getValueType(0) && 94 "Type twice as big as expanded type not itself expanded!"); 95 MVT NVT = TLI.getTypeToTransformTo(N->getValueType(0)); 96 97 Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, NVT, Part, 98 DAG.getConstant(0, TLI.getPointerTy())); 99 Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, NVT, Part, 100 DAG.getConstant(1, TLI.getPointerTy())); 101} 102 103void DAGTypeLegalizer::ExpandRes_EXTRACT_VECTOR_ELT(SDNode *N, SDValue &Lo, 104 SDValue &Hi) { 105 SDValue OldVec = N->getOperand(0); 106 unsigned OldElts = OldVec.getValueType().getVectorNumElements(); 107 108 // Convert to a vector of the expanded element type, for example 109 // <3 x i64> -> <6 x i32>. 110 MVT OldVT = N->getValueType(0); 111 MVT NewVT = TLI.getTypeToTransformTo(OldVT); 112 113 SDValue NewVec = DAG.getNode(ISD::BIT_CONVERT, 114 MVT::getVectorVT(NewVT, 2*OldElts), 115 OldVec); 116 117 // Extract the elements at 2 * Idx and 2 * Idx + 1 from the new vector. 118 SDValue Idx = N->getOperand(1); 119 120 // Make sure the type of Idx is big enough to hold the new values. 121 if (Idx.getValueType().bitsLT(TLI.getPointerTy())) 122 Idx = DAG.getNode(ISD::ZERO_EXTEND, TLI.getPointerTy(), Idx); 123 124 Idx = DAG.getNode(ISD::ADD, Idx.getValueType(), Idx, Idx); 125 Lo = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, NewVT, NewVec, Idx); 126 127 Idx = DAG.getNode(ISD::ADD, Idx.getValueType(), Idx, 128 DAG.getConstant(1, Idx.getValueType())); 129 Hi = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, NewVT, NewVec, Idx); 130 131 if (TLI.isBigEndian()) 132 std::swap(Lo, Hi); 133} 134 135void DAGTypeLegalizer::ExpandRes_NormalLoad(SDNode *N, SDValue &Lo, 136 SDValue &Hi) { 137 assert(ISD::isNormalLoad(N) && "This routine only for normal loads!"); 138 139 LoadSDNode *LD = cast<LoadSDNode>(N); 140 MVT NVT = TLI.getTypeToTransformTo(LD->getValueType(0)); 141 SDValue Chain = LD->getChain(); 142 SDValue Ptr = LD->getBasePtr(); 143 int SVOffset = LD->getSrcValueOffset(); 144 unsigned Alignment = LD->getAlignment(); 145 bool isVolatile = LD->isVolatile(); 146 147 assert(NVT.isByteSized() && "Expanded type not byte sized!"); 148 149 Lo = DAG.getLoad(NVT, Chain, Ptr, LD->getSrcValue(), SVOffset, 150 isVolatile, Alignment); 151 152 // Increment the pointer to the other half. 153 unsigned IncrementSize = NVT.getSizeInBits() / 8; 154 Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr, 155 DAG.getIntPtrConstant(IncrementSize)); 156 Hi = DAG.getLoad(NVT, Chain, Ptr, LD->getSrcValue(), SVOffset+IncrementSize, 157 isVolatile, MinAlign(Alignment, IncrementSize)); 158 159 // Build a factor node to remember that this load is independent of the 160 // other one. 161 Chain = DAG.getNode(ISD::TokenFactor, MVT::Other, Lo.getValue(1), 162 Hi.getValue(1)); 163 164 // Handle endianness of the load. 165 if (TLI.isBigEndian()) 166 std::swap(Lo, Hi); 167 168 // Modified the chain - switch anything that used the old chain to use 169 // the new one. 170 ReplaceValueWith(SDValue(N, 1), Chain); 171} 172 173 174//===--------------------------------------------------------------------===// 175// Generic Operand Expansion. 176//===--------------------------------------------------------------------===// 177 178SDValue DAGTypeLegalizer::ExpandOp_BIT_CONVERT(SDNode *N) { 179 if (N->getValueType(0).isVector()) { 180 // An illegal expanding type is being converted to a legal vector type. 181 // Make a two element vector out of the expanded parts and convert that 182 // instead, but only if the new vector type is legal (otherwise there 183 // is no point, and it might create expansion loops). For example, on 184 // x86 this turns v1i64 = BIT_CONVERT i64 into v1i64 = BIT_CONVERT v2i32. 185 MVT OVT = N->getOperand(0).getValueType(); 186 MVT NVT = MVT::getVectorVT(TLI.getTypeToTransformTo(OVT), 2); 187 188 if (isTypeLegal(NVT)) { 189 SDValue Parts[2]; 190 GetExpandedOp(N->getOperand(0), Parts[0], Parts[1]); 191 192 if (TLI.isBigEndian()) 193 std::swap(Parts[0], Parts[1]); 194 195 SDValue Vec = DAG.getNode(ISD::BUILD_VECTOR, NVT, Parts, 2); 196 return DAG.getNode(ISD::BIT_CONVERT, N->getValueType(0), Vec); 197 } 198 } 199 200 // Otherwise, store to a temporary and load out again as the new type. 201 return CreateStackStoreLoad(N->getOperand(0), N->getValueType(0)); 202} 203 204SDValue DAGTypeLegalizer::ExpandOp_BUILD_VECTOR(SDNode *N) { 205 // The vector type is legal but the element type needs expansion. 206 MVT VecVT = N->getValueType(0); 207 unsigned NumElts = VecVT.getVectorNumElements(); 208 MVT OldVT = N->getOperand(0).getValueType(); 209 MVT NewVT = TLI.getTypeToTransformTo(OldVT); 210 211 // Build a vector of twice the length out of the expanded elements. 212 // For example <3 x i64> -> <6 x i32>. 213 std::vector<SDValue> NewElts; 214 NewElts.reserve(NumElts*2); 215 216 for (unsigned i = 0; i < NumElts; ++i) { 217 SDValue Lo, Hi; 218 GetExpandedOp(N->getOperand(i), Lo, Hi); 219 if (TLI.isBigEndian()) 220 std::swap(Lo, Hi); 221 NewElts.push_back(Lo); 222 NewElts.push_back(Hi); 223 } 224 225 SDValue NewVec = DAG.getNode(ISD::BUILD_VECTOR, 226 MVT::getVectorVT(NewVT, NewElts.size()), 227 &NewElts[0], NewElts.size()); 228 229 // Convert the new vector to the old vector type. 230 return DAG.getNode(ISD::BIT_CONVERT, VecVT, NewVec); 231} 232 233SDValue DAGTypeLegalizer::ExpandOp_EXTRACT_ELEMENT(SDNode *N) { 234 SDValue Lo, Hi; 235 GetExpandedOp(N->getOperand(0), Lo, Hi); 236 return cast<ConstantSDNode>(N->getOperand(1))->getValue() ? Hi : Lo; 237} 238 239SDValue DAGTypeLegalizer::ExpandOp_NormalStore(SDNode *N, unsigned OpNo) { 240 assert(ISD::isNormalStore(N) && "This routine only for normal stores!"); 241 assert(OpNo == 1 && "Can only expand the stored value so far"); 242 243 StoreSDNode *St = cast<StoreSDNode>(N); 244 MVT NVT = TLI.getTypeToTransformTo(St->getValue().getValueType()); 245 SDValue Chain = St->getChain(); 246 SDValue Ptr = St->getBasePtr(); 247 int SVOffset = St->getSrcValueOffset(); 248 unsigned Alignment = St->getAlignment(); 249 bool isVolatile = St->isVolatile(); 250 251 assert(NVT.isByteSized() && "Expanded type not byte sized!"); 252 unsigned IncrementSize = NVT.getSizeInBits() / 8; 253 254 SDValue Lo, Hi; 255 GetExpandedOp(St->getValue(), Lo, Hi); 256 257 if (TLI.isBigEndian()) 258 std::swap(Lo, Hi); 259 260 Lo = DAG.getStore(Chain, Lo, Ptr, St->getSrcValue(), SVOffset, 261 isVolatile, Alignment); 262 263 Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr, 264 DAG.getIntPtrConstant(IncrementSize)); 265 assert(isTypeLegal(Ptr.getValueType()) && "Pointers must be legal!"); 266 Hi = DAG.getStore(Chain, Hi, Ptr, St->getSrcValue(), SVOffset + IncrementSize, 267 isVolatile, MinAlign(Alignment, IncrementSize)); 268 269 return DAG.getNode(ISD::TokenFactor, MVT::Other, Lo, Hi); 270} 271 272 273//===--------------------------------------------------------------------===// 274// Generic Result Splitting. 275//===--------------------------------------------------------------------===// 276 277// Be careful to make no assumptions about which of Lo/Hi is stored first in 278// memory (for vectors it is always Lo first followed by Hi in the following 279// bytes; for integers and floats it is Lo first if and only if the machine is 280// little-endian). 281 282void DAGTypeLegalizer::SplitRes_MERGE_VALUES(SDNode *N, 283 SDValue &Lo, SDValue &Hi) { 284 // A MERGE_VALUES node can produce any number of values. We know that the 285 // first illegal one needs to be expanded into Lo/Hi. 286 unsigned i; 287 288 // The string of legal results gets turns into the input operands, which have 289 // the same type. 290 for (i = 0; isTypeLegal(N->getValueType(i)); ++i) 291 ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i))); 292 293 // The first illegal result must be the one that needs to be expanded. 294 GetSplitOp(N->getOperand(i), Lo, Hi); 295 296 // Legalize the rest of the results into the input operands whether they are 297 // legal or not. 298 unsigned e = N->getNumValues(); 299 for (++i; i != e; ++i) 300 ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i))); 301} 302 303void DAGTypeLegalizer::SplitRes_SELECT(SDNode *N, SDValue &Lo, 304 SDValue &Hi) { 305 SDValue LL, LH, RL, RH; 306 GetSplitOp(N->getOperand(1), LL, LH); 307 GetSplitOp(N->getOperand(2), RL, RH); 308 309 SDValue Cond = N->getOperand(0); 310 Lo = DAG.getNode(ISD::SELECT, LL.getValueType(), Cond, LL, RL); 311 Hi = DAG.getNode(ISD::SELECT, LH.getValueType(), Cond, LH, RH); 312} 313 314void DAGTypeLegalizer::SplitRes_SELECT_CC(SDNode *N, SDValue &Lo, 315 SDValue &Hi) { 316 SDValue LL, LH, RL, RH; 317 GetSplitOp(N->getOperand(2), LL, LH); 318 GetSplitOp(N->getOperand(3), RL, RH); 319 320 Lo = DAG.getNode(ISD::SELECT_CC, LL.getValueType(), N->getOperand(0), 321 N->getOperand(1), LL, RL, N->getOperand(4)); 322 Hi = DAG.getNode(ISD::SELECT_CC, LH.getValueType(), N->getOperand(0), 323 N->getOperand(1), LH, RH, N->getOperand(4)); 324} 325 326void DAGTypeLegalizer::SplitRes_UNDEF(SDNode *N, SDValue &Lo, SDValue &Hi) { 327 MVT LoVT, HiVT; 328 GetSplitDestVTs(N->getValueType(0), LoVT, HiVT); 329 Lo = DAG.getNode(ISD::UNDEF, LoVT); 330 Hi = DAG.getNode(ISD::UNDEF, HiVT); 331} 332