LegalizeTypesGeneric.cpp revision 2bee0afb7d023e029975abf7d3157759fa797d37 
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"
21#include "llvm/Target/TargetData.h"
22#include "llvm/CodeGen/PseudoSourceValue.h"
23using namespace llvm;
24
25//===----------------------------------------------------------------------===//
26// Generic Result Expansion.
27//===----------------------------------------------------------------------===//
28
29// These routines assume that the Lo/Hi part is stored first in memory on
30// little/big-endian machines, followed by the Hi/Lo part.  This means that
31// they cannot be used as is on vectors, for which Lo is always stored first.
32
33void DAGTypeLegalizer::ExpandRes_BIT_CONVERT(SDNode *N, SDValue &Lo,
34                                             SDValue &Hi) {
35  MVT OutVT = N->getValueType(0);
36  MVT NOutVT = TLI.getTypeToTransformTo(OutVT);
37  SDValue InOp = N->getOperand(0);
38  MVT InVT = InOp.getValueType();
39  DebugLoc dl = N->getDebugLoc();
40
41  // Handle some special cases efficiently.
42  switch (getTypeAction(InVT)) {
43    default:
44      assert(false && "Unknown type action!");
45    case Legal:
46    case PromoteInteger:
47      break;
48    case SoftenFloat:
49      // Convert the integer operand instead.
50      SplitInteger(GetSoftenedFloat(InOp), Lo, Hi);
51      Lo = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Lo);
52      Hi = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Hi);
53      return;
54    case ExpandInteger:
55    case ExpandFloat:
56      // Convert the expanded pieces of the input.
57      GetExpandedOp(InOp, Lo, Hi);
58      Lo = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Lo);
59      Hi = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Hi);
60      return;
61    case SplitVector:
62      // Convert the split parts of the input if it was split in two.
63      GetSplitVector(InOp, Lo, Hi);
64      if (Lo.getValueType() == Hi.getValueType()) {
65        if (TLI.isBigEndian())
66          std::swap(Lo, Hi);
67        Lo = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Lo);
68        Hi = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Hi);
69        return;
70      }
71      break;
72    case ScalarizeVector:
73      // Convert the element instead.
74      SplitInteger(BitConvertToInteger(GetScalarizedVector(InOp)), Lo, Hi);
75      Lo = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Lo);
76      Hi = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Hi);
77      return;
78    case WidenVector: {
79      assert(!(InVT.getVectorNumElements() & 1) && "Unsupported BIT_CONVERT");
80      InOp = GetWidenedVector(InOp);
81      MVT InNVT = MVT::getVectorVT(InVT.getVectorElementType(),
82                                   InVT.getVectorNumElements()/2);
83      Lo = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, InNVT, InOp,
84                       DAG.getIntPtrConstant(0));
85      Hi = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, InNVT, InOp,
86                       DAG.getIntPtrConstant(InNVT.getVectorNumElements()));
87      if (TLI.isBigEndian())
88        std::swap(Lo, Hi);
89      Lo = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Lo);
90      Hi = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Hi);
91      return;
92    }
93  }
94
95  // Lower the bit-convert to a store/load from the stack.
96  assert(NOutVT.isByteSized() && "Expanded type not byte sized!");
97
98  // Create the stack frame object.  Make sure it is aligned for both
99  // the source and expanded destination types.
100  unsigned Alignment =
101    TLI.getTargetData()->getPrefTypeAlignment(NOutVT.getTypeForMVT());
102  SDValue StackPtr = DAG.CreateStackTemporary(InVT, Alignment);
103  int SPFI = cast<FrameIndexSDNode>(StackPtr.getNode())->getIndex();
104  const Value *SV = PseudoSourceValue::getFixedStack(SPFI);
105
106  // Emit a store to the stack slot.
107  SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, InOp, StackPtr, SV, 0);
108
109  // Load the first half from the stack slot.
110  Lo = DAG.getLoad(NOutVT, dl, Store, StackPtr, SV, 0);
111
112  // Increment the pointer to the other half.
113  unsigned IncrementSize = NOutVT.getSizeInBits() / 8;
114  StackPtr = DAG.getNode(ISD::ADD, dl, StackPtr.getValueType(), StackPtr,
115                         DAG.getIntPtrConstant(IncrementSize));
116
117  // Load the second half from the stack slot.
118  Hi = DAG.getLoad(NOutVT, dl, Store, StackPtr, SV, IncrementSize, false,
119                   MinAlign(Alignment, IncrementSize));
120
121  // Handle endianness of the load.
122  if (TLI.isBigEndian())
123    std::swap(Lo, Hi);
124}
125
126void DAGTypeLegalizer::ExpandRes_BUILD_PAIR(SDNode *N, SDValue &Lo,
127                                            SDValue &Hi) {
128  // Return the operands.
129  Lo = N->getOperand(0);
130  Hi = N->getOperand(1);
131}
132
133void DAGTypeLegalizer::ExpandRes_EXTRACT_ELEMENT(SDNode *N, SDValue &Lo,
134                                                 SDValue &Hi) {
135  GetExpandedOp(N->getOperand(0), Lo, Hi);
136  SDValue Part = cast<ConstantSDNode>(N->getOperand(1))->getZExtValue() ?
137                   Hi : Lo;
138
139  assert(Part.getValueType() == N->getValueType(0) &&
140         "Type twice as big as expanded type not itself expanded!");
141
142  GetPairElements(Part, Lo, Hi);
143}
144
145void DAGTypeLegalizer::ExpandRes_EXTRACT_VECTOR_ELT(SDNode *N, SDValue &Lo,
146                                                    SDValue &Hi) {
147  SDValue OldVec = N->getOperand(0);
148  unsigned OldElts = OldVec.getValueType().getVectorNumElements();
149  DebugLoc dl = N->getDebugLoc();
150
151  // Convert to a vector of the expanded element type, for example
152  // <3 x i64> -> <6 x i32>.
153  MVT OldVT = N->getValueType(0);
154  MVT NewVT = TLI.getTypeToTransformTo(OldVT);
155
156  SDValue NewVec = DAG.getNode(ISD::BIT_CONVERT, dl,
157                                 MVT::getVectorVT(NewVT, 2*OldElts),
158                                 OldVec);
159
160  // Extract the elements at 2 * Idx and 2 * Idx + 1 from the new vector.
161  SDValue Idx = N->getOperand(1);
162
163  // Make sure the type of Idx is big enough to hold the new values.
164  if (Idx.getValueType().bitsLT(TLI.getPointerTy()))
165    Idx = DAG.getNode(ISD::ZERO_EXTEND, dl, TLI.getPointerTy(), Idx);
166
167  Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx, Idx);
168  Lo = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, NewVT, NewVec, Idx);
169
170  Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx,
171                    DAG.getConstant(1, Idx.getValueType()));
172  Hi = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, NewVT, NewVec, Idx);
173
174  if (TLI.isBigEndian())
175    std::swap(Lo, Hi);
176}
177
178void DAGTypeLegalizer::ExpandRes_NormalLoad(SDNode *N, SDValue &Lo,
179                                            SDValue &Hi) {
180  assert(ISD::isNormalLoad(N) && "This routine only for normal loads!");
181  DebugLoc dl = N->getDebugLoc();
182
183  LoadSDNode *LD = cast<LoadSDNode>(N);
184  MVT NVT = TLI.getTypeToTransformTo(LD->getValueType(0));
185  SDValue Chain = LD->getChain();
186  SDValue Ptr = LD->getBasePtr();
187  int SVOffset = LD->getSrcValueOffset();
188  unsigned Alignment = LD->getAlignment();
189  bool isVolatile = LD->isVolatile();
190
191  assert(NVT.isByteSized() && "Expanded type not byte sized!");
192
193  Lo = DAG.getLoad(NVT, dl, Chain, Ptr, LD->getSrcValue(), SVOffset,
194                   isVolatile, Alignment);
195
196  // Increment the pointer to the other half.
197  unsigned IncrementSize = NVT.getSizeInBits() / 8;
198  Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
199                    DAG.getIntPtrConstant(IncrementSize));
200  Hi = DAG.getLoad(NVT, dl, Chain, Ptr, LD->getSrcValue(),
201                   SVOffset+IncrementSize,
202                   isVolatile, MinAlign(Alignment, IncrementSize));
203
204  // Build a factor node to remember that this load is independent of the
205  // other one.
206  Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo.getValue(1),
207                      Hi.getValue(1));
208
209  // Handle endianness of the load.
210  if (TLI.isBigEndian())
211    std::swap(Lo, Hi);
212
213  // Modified the chain - switch anything that used the old chain to use
214  // the new one.
215  ReplaceValueWith(SDValue(N, 1), Chain);
216}
217
218void DAGTypeLegalizer::ExpandRes_VAARG(SDNode *N, SDValue &Lo, SDValue &Hi) {
219  MVT NVT = TLI.getTypeToTransformTo(N->getValueType(0));
220  SDValue Chain = N->getOperand(0);
221  SDValue Ptr = N->getOperand(1);
222  DebugLoc dl = N->getDebugLoc();
223
224  Lo = DAG.getVAArg(NVT, dl, Chain, Ptr, N->getOperand(2));
225  Hi = DAG.getVAArg(NVT, dl, Lo.getValue(1), Ptr, N->getOperand(2));
226
227  // Handle endianness of the load.
228  if (TLI.isBigEndian())
229    std::swap(Lo, Hi);
230
231  // Modified the chain - switch anything that used the old chain to use
232  // the new one.
233  ReplaceValueWith(SDValue(N, 1), Hi.getValue(1));
234}
235
236
237//===--------------------------------------------------------------------===//
238// Generic Operand Expansion.
239//===--------------------------------------------------------------------===//
240
241SDValue DAGTypeLegalizer::ExpandOp_BIT_CONVERT(SDNode *N) {
242  DebugLoc dl = N->getDebugLoc();
243  if (N->getValueType(0).isVector()) {
244    // An illegal expanding type is being converted to a legal vector type.
245    // Make a two element vector out of the expanded parts and convert that
246    // instead, but only if the new vector type is legal (otherwise there
247    // is no point, and it might create expansion loops).  For example, on
248    // x86 this turns v1i64 = BIT_CONVERT i64 into v1i64 = BIT_CONVERT v2i32.
249    MVT OVT = N->getOperand(0).getValueType();
250    MVT NVT = MVT::getVectorVT(TLI.getTypeToTransformTo(OVT), 2);
251
252    if (isTypeLegal(NVT)) {
253      SDValue Parts[2];
254      GetExpandedOp(N->getOperand(0), Parts[0], Parts[1]);
255
256      if (TLI.isBigEndian())
257        std::swap(Parts[0], Parts[1]);
258
259      SDValue Vec = DAG.getNode(ISD::BUILD_VECTOR, dl, NVT, Parts, 2);
260      return DAG.getNode(ISD::BIT_CONVERT, dl, N->getValueType(0), Vec);
261    }
262  }
263
264  // Otherwise, store to a temporary and load out again as the new type.
265  return CreateStackStoreLoad(N->getOperand(0), N->getValueType(0));
266}
267
268SDValue DAGTypeLegalizer::ExpandOp_BUILD_VECTOR(SDNode *N) {
269  // The vector type is legal but the element type needs expansion.
270  MVT VecVT = N->getValueType(0);
271  unsigned NumElts = VecVT.getVectorNumElements();
272  MVT OldVT = N->getOperand(0).getValueType();
273  MVT NewVT = TLI.getTypeToTransformTo(OldVT);
274  DebugLoc dl = N->getDebugLoc();
275
276  assert(OldVT == VecVT.getVectorElementType() &&
277         "BUILD_VECTOR operand type doesn't match vector element type!");
278
279  // Build a vector of twice the length out of the expanded elements.
280  // For example <3 x i64> -> <6 x i32>.
281  std::vector<SDValue> NewElts;
282  NewElts.reserve(NumElts*2);
283
284  for (unsigned i = 0; i < NumElts; ++i) {
285    SDValue Lo, Hi;
286    GetExpandedOp(N->getOperand(i), Lo, Hi);
287    if (TLI.isBigEndian())
288      std::swap(Lo, Hi);
289    NewElts.push_back(Lo);
290    NewElts.push_back(Hi);
291  }
292
293  SDValue NewVec = DAG.getNode(ISD::BUILD_VECTOR, dl,
294                                 MVT::getVectorVT(NewVT, NewElts.size()),
295                                 &NewElts[0], NewElts.size());
296
297  // Convert the new vector to the old vector type.
298  return DAG.getNode(ISD::BIT_CONVERT, dl, VecVT, NewVec);
299}
300
301SDValue DAGTypeLegalizer::ExpandOp_EXTRACT_ELEMENT(SDNode *N) {
302  SDValue Lo, Hi;
303  GetExpandedOp(N->getOperand(0), Lo, Hi);
304  return cast<ConstantSDNode>(N->getOperand(1))->getZExtValue() ? Hi : Lo;
305}
306
307SDValue DAGTypeLegalizer::ExpandOp_INSERT_VECTOR_ELT(SDNode *N) {
308  // The vector type is legal but the element type needs expansion.
309  MVT VecVT = N->getValueType(0);
310  unsigned NumElts = VecVT.getVectorNumElements();
311  DebugLoc dl = N->getDebugLoc();
312
313  SDValue Val = N->getOperand(1);
314  MVT OldEVT = Val.getValueType();
315  MVT NewEVT = TLI.getTypeToTransformTo(OldEVT);
316
317  assert(OldEVT == VecVT.getVectorElementType() &&
318         "Inserted element type doesn't match vector element type!");
319
320  // Bitconvert to a vector of twice the length with elements of the expanded
321  // type, insert the expanded vector elements, and then convert back.
322  MVT NewVecVT = MVT::getVectorVT(NewEVT, NumElts*2);
323  SDValue NewVec = DAG.getNode(ISD::BIT_CONVERT, dl,
324                               NewVecVT, N->getOperand(0));
325
326  SDValue Lo, Hi;
327  GetExpandedOp(Val, Lo, Hi);
328  if (TLI.isBigEndian())
329    std::swap(Lo, Hi);
330
331  SDValue Idx = N->getOperand(2);
332  Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx, Idx);
333  NewVec = DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, NewVecVT, NewVec, Lo, Idx);
334  Idx = DAG.getNode(ISD::ADD, dl,
335                    Idx.getValueType(), Idx, DAG.getIntPtrConstant(1));
336  NewVec =  DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, NewVecVT, NewVec, Hi, Idx);
337
338  // Convert the new vector to the old vector type.
339  return DAG.getNode(ISD::BIT_CONVERT, dl, VecVT, NewVec);
340}
341
342SDValue DAGTypeLegalizer::ExpandOp_SCALAR_TO_VECTOR(SDNode *N) {
343  DebugLoc dl = N->getDebugLoc();
344  MVT VT = N->getValueType(0);
345  assert(VT.getVectorElementType() == N->getOperand(0).getValueType() &&
346         "SCALAR_TO_VECTOR operand type doesn't match vector element type!");
347  unsigned NumElts = VT.getVectorNumElements();
348  SmallVector<SDValue, 16> Ops(NumElts);
349  Ops[0] = N->getOperand(0);
350  SDValue UndefVal = DAG.getUNDEF(Ops[0].getValueType());
351  for (unsigned i = 1; i < NumElts; ++i)
352    Ops[i] = UndefVal;
353  return DAG.getNode(ISD::BUILD_VECTOR, dl, VT, &Ops[0], NumElts);
354}
355
356SDValue DAGTypeLegalizer::ExpandOp_NormalStore(SDNode *N, unsigned OpNo) {
357  assert(ISD::isNormalStore(N) && "This routine only for normal stores!");
358  assert(OpNo == 1 && "Can only expand the stored value so far");
359  DebugLoc dl = N->getDebugLoc();
360
361  StoreSDNode *St = cast<StoreSDNode>(N);
362  MVT NVT = TLI.getTypeToTransformTo(St->getValue().getValueType());
363  SDValue Chain = St->getChain();
364  SDValue Ptr = St->getBasePtr();
365  int SVOffset = St->getSrcValueOffset();
366  unsigned Alignment = St->getAlignment();
367  bool isVolatile = St->isVolatile();
368
369  assert(NVT.isByteSized() && "Expanded type not byte sized!");
370  unsigned IncrementSize = NVT.getSizeInBits() / 8;
371
372  SDValue Lo, Hi;
373  GetExpandedOp(St->getValue(), Lo, Hi);
374
375  if (TLI.isBigEndian())
376    std::swap(Lo, Hi);
377
378  Lo = DAG.getStore(Chain, dl, Lo, Ptr, St->getSrcValue(), SVOffset,
379                    isVolatile, Alignment);
380
381  Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
382                    DAG.getIntPtrConstant(IncrementSize));
383  assert(isTypeLegal(Ptr.getValueType()) && "Pointers must be legal!");
384  Hi = DAG.getStore(Chain, dl, Hi, Ptr, St->getSrcValue(),
385                    SVOffset + IncrementSize,
386                    isVolatile, MinAlign(Alignment, IncrementSize));
387
388  return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo, Hi);
389}
390
391
392//===--------------------------------------------------------------------===//
393// Generic Result Splitting.
394//===--------------------------------------------------------------------===//
395
396// Be careful to make no assumptions about which of Lo/Hi is stored first in
397// memory (for vectors it is always Lo first followed by Hi in the following
398// bytes; for integers and floats it is Lo first if and only if the machine is
399// little-endian).
400
401void DAGTypeLegalizer::SplitRes_MERGE_VALUES(SDNode *N,
402                                             SDValue &Lo, SDValue &Hi) {
403  // A MERGE_VALUES node can produce any number of values.  We know that the
404  // first illegal one needs to be expanded into Lo/Hi.
405  unsigned i;
406
407  // The string of legal results gets turned into input operands, which have
408  // the same type.
409  for (i = 0; isTypeLegal(N->getValueType(i)); ++i)
410    ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i)));
411
412  // The first illegal result must be the one that needs to be expanded.
413  GetSplitOp(N->getOperand(i), Lo, Hi);
414
415  // Legalize the rest of the results into the input operands whether they are
416  // legal or not.
417  unsigned e = N->getNumValues();
418  for (++i; i != e; ++i)
419    ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i)));
420}
421
422void DAGTypeLegalizer::SplitRes_SELECT(SDNode *N, SDValue &Lo,
423                                       SDValue &Hi) {
424  SDValue LL, LH, RL, RH;
425  DebugLoc dl = N->getDebugLoc();
426  GetSplitOp(N->getOperand(1), LL, LH);
427  GetSplitOp(N->getOperand(2), RL, RH);
428
429  SDValue Cond = N->getOperand(0);
430  Lo = DAG.getNode(ISD::SELECT, dl, LL.getValueType(), Cond, LL, RL);
431  Hi = DAG.getNode(ISD::SELECT, dl, LH.getValueType(), Cond, LH, RH);
432}
433
434void DAGTypeLegalizer::SplitRes_SELECT_CC(SDNode *N, SDValue &Lo,
435                                          SDValue &Hi) {
436  SDValue LL, LH, RL, RH;
437  DebugLoc dl = N->getDebugLoc();
438  GetSplitOp(N->getOperand(2), LL, LH);
439  GetSplitOp(N->getOperand(3), RL, RH);
440
441  Lo = DAG.getNode(ISD::SELECT_CC, dl, LL.getValueType(), N->getOperand(0),
442                   N->getOperand(1), LL, RL, N->getOperand(4));
443  Hi = DAG.getNode(ISD::SELECT_CC, dl, LH.getValueType(), N->getOperand(0),
444                   N->getOperand(1), LH, RH, N->getOperand(4));
445}
446
447void DAGTypeLegalizer::SplitRes_UNDEF(SDNode *N, SDValue &Lo, SDValue &Hi) {
448  MVT LoVT, HiVT;
449  DebugLoc dl = N->getDebugLoc();
450  GetSplitDestVTs(N->getValueType(0), LoVT, HiVT);
451  Lo = DAG.getUNDEF(LoVT);
452  Hi = DAG.getUNDEF(HiVT);
453}
454