LegalizeTypesGeneric.cpp revision 1b127eaad4867eb33176b5d65c0f043cf015e365 
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  DebugLoc dl = N->getDebugLoc();
139
140  assert(Part.getValueType() == N->getValueType(0) &&
141         "Type twice as big as expanded type not itself expanded!");
142  MVT NVT = TLI.getTypeToTransformTo(N->getValueType(0));
143
144  Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Part,
145                   DAG.getConstant(0, TLI.getPointerTy()));
146  Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Part,
147                   DAG.getConstant(1, TLI.getPointerTy()));
148}
149
150void DAGTypeLegalizer::ExpandRes_EXTRACT_VECTOR_ELT(SDNode *N, SDValue &Lo,
151                                                    SDValue &Hi) {
152  SDValue OldVec = N->getOperand(0);
153  unsigned OldElts = OldVec.getValueType().getVectorNumElements();
154  DebugLoc dl = N->getDebugLoc();
155
156  // Convert to a vector of the expanded element type, for example
157  // <3 x i64> -> <6 x i32>.
158  MVT OldVT = N->getValueType(0);
159  MVT NewVT = TLI.getTypeToTransformTo(OldVT);
160
161  SDValue NewVec = DAG.getNode(ISD::BIT_CONVERT, dl,
162                                 MVT::getVectorVT(NewVT, 2*OldElts),
163                                 OldVec);
164
165  // Extract the elements at 2 * Idx and 2 * Idx + 1 from the new vector.
166  SDValue Idx = N->getOperand(1);
167
168  // Make sure the type of Idx is big enough to hold the new values.
169  if (Idx.getValueType().bitsLT(TLI.getPointerTy()))
170    Idx = DAG.getNode(ISD::ZERO_EXTEND, dl, TLI.getPointerTy(), Idx);
171
172  Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx, Idx);
173  Lo = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, NewVT, NewVec, Idx);
174
175  Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx,
176                    DAG.getConstant(1, Idx.getValueType()));
177  Hi = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, NewVT, NewVec, Idx);
178
179  if (TLI.isBigEndian())
180    std::swap(Lo, Hi);
181}
182
183void DAGTypeLegalizer::ExpandRes_NormalLoad(SDNode *N, SDValue &Lo,
184                                            SDValue &Hi) {
185  assert(ISD::isNormalLoad(N) && "This routine only for normal loads!");
186  DebugLoc dl = N->getDebugLoc();
187
188  LoadSDNode *LD = cast<LoadSDNode>(N);
189  MVT NVT = TLI.getTypeToTransformTo(LD->getValueType(0));
190  SDValue Chain = LD->getChain();
191  SDValue Ptr = LD->getBasePtr();
192  int SVOffset = LD->getSrcValueOffset();
193  unsigned Alignment = LD->getAlignment();
194  bool isVolatile = LD->isVolatile();
195
196  assert(NVT.isByteSized() && "Expanded type not byte sized!");
197
198  Lo = DAG.getLoad(NVT, dl, Chain, Ptr, LD->getSrcValue(), SVOffset,
199                   isVolatile, Alignment);
200
201  // Increment the pointer to the other half.
202  unsigned IncrementSize = NVT.getSizeInBits() / 8;
203  Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
204                    DAG.getIntPtrConstant(IncrementSize));
205  Hi = DAG.getLoad(NVT, dl, Chain, Ptr, LD->getSrcValue(),
206                   SVOffset+IncrementSize,
207                   isVolatile, MinAlign(Alignment, IncrementSize));
208
209  // Build a factor node to remember that this load is independent of the
210  // other one.
211  Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo.getValue(1),
212                      Hi.getValue(1));
213
214  // Handle endianness of the load.
215  if (TLI.isBigEndian())
216    std::swap(Lo, Hi);
217
218  // Modified the chain - switch anything that used the old chain to use
219  // the new one.
220  ReplaceValueWith(SDValue(N, 1), Chain);
221}
222
223void DAGTypeLegalizer::ExpandRes_VAARG(SDNode *N, SDValue &Lo, SDValue &Hi) {
224  MVT NVT = TLI.getTypeToTransformTo(N->getValueType(0));
225  SDValue Chain = N->getOperand(0);
226  SDValue Ptr = N->getOperand(1);
227  DebugLoc dl = N->getDebugLoc();
228
229  Lo = DAG.getVAArg(NVT, dl, Chain, Ptr, N->getOperand(2));
230  Hi = DAG.getVAArg(NVT, dl, Lo.getValue(1), Ptr, N->getOperand(2));
231
232  // Handle endianness of the load.
233  if (TLI.isBigEndian())
234    std::swap(Lo, Hi);
235
236  // Modified the chain - switch anything that used the old chain to use
237  // the new one.
238  ReplaceValueWith(SDValue(N, 1), Hi.getValue(1));
239}
240
241
242//===--------------------------------------------------------------------===//
243// Generic Operand Expansion.
244//===--------------------------------------------------------------------===//
245
246SDValue DAGTypeLegalizer::ExpandOp_BIT_CONVERT(SDNode *N) {
247  DebugLoc dl = N->getDebugLoc();
248  if (N->getValueType(0).isVector()) {
249    // An illegal expanding type is being converted to a legal vector type.
250    // Make a two element vector out of the expanded parts and convert that
251    // instead, but only if the new vector type is legal (otherwise there
252    // is no point, and it might create expansion loops).  For example, on
253    // x86 this turns v1i64 = BIT_CONVERT i64 into v1i64 = BIT_CONVERT v2i32.
254    MVT OVT = N->getOperand(0).getValueType();
255    MVT NVT = MVT::getVectorVT(TLI.getTypeToTransformTo(OVT), 2);
256
257    if (isTypeLegal(NVT)) {
258      SDValue Parts[2];
259      GetExpandedOp(N->getOperand(0), Parts[0], Parts[1]);
260
261      if (TLI.isBigEndian())
262        std::swap(Parts[0], Parts[1]);
263
264      SDValue Vec = DAG.getNode(ISD::BUILD_VECTOR, dl, NVT, Parts, 2);
265      return DAG.getNode(ISD::BIT_CONVERT, dl, N->getValueType(0), Vec);
266    }
267  }
268
269  // Otherwise, store to a temporary and load out again as the new type.
270  return CreateStackStoreLoad(N->getOperand(0), N->getValueType(0));
271}
272
273SDValue DAGTypeLegalizer::ExpandOp_BUILD_VECTOR(SDNode *N) {
274  // The vector type is legal but the element type needs expansion.
275  MVT VecVT = N->getValueType(0);
276  unsigned NumElts = VecVT.getVectorNumElements();
277  MVT OldVT = N->getOperand(0).getValueType();
278  MVT NewVT = TLI.getTypeToTransformTo(OldVT);
279  DebugLoc dl = N->getDebugLoc();
280
281  // Build a vector of twice the length out of the expanded elements.
282  // For example <3 x i64> -> <6 x i32>.
283  std::vector<SDValue> NewElts;
284  NewElts.reserve(NumElts*2);
285
286  for (unsigned i = 0; i < NumElts; ++i) {
287    SDValue Lo, Hi;
288    GetExpandedOp(N->getOperand(i), Lo, Hi);
289    if (TLI.isBigEndian())
290      std::swap(Lo, Hi);
291    NewElts.push_back(Lo);
292    NewElts.push_back(Hi);
293  }
294
295  SDValue NewVec = DAG.getNode(ISD::BUILD_VECTOR, dl,
296                                 MVT::getVectorVT(NewVT, NewElts.size()),
297                                 &NewElts[0], NewElts.size());
298
299  // Convert the new vector to the old vector type.
300  return DAG.getNode(ISD::BIT_CONVERT, dl, VecVT, NewVec);
301}
302
303SDValue DAGTypeLegalizer::ExpandOp_EXTRACT_ELEMENT(SDNode *N) {
304  SDValue Lo, Hi;
305  GetExpandedOp(N->getOperand(0), Lo, Hi);
306  return cast<ConstantSDNode>(N->getOperand(1))->getZExtValue() ? Hi : Lo;
307}
308
309SDValue DAGTypeLegalizer::ExpandOp_INSERT_VECTOR_ELT(SDNode *N) {
310  // The vector type is legal but the element type needs expansion.
311  MVT VecVT = N->getValueType(0);
312  unsigned NumElts = VecVT.getVectorNumElements();
313  DebugLoc dl = N->getDebugLoc();
314
315  SDValue Val = N->getOperand(1);
316  MVT OldEVT = Val.getValueType();
317  MVT NewEVT = TLI.getTypeToTransformTo(OldEVT);
318
319  assert(OldEVT == VecVT.getVectorElementType() &&
320         "Inserted element type doesn't match vector element type!");
321
322  // Bitconvert to a vector of twice the length with elements of the expanded
323  // type, insert the expanded vector elements, and then convert back.
324  MVT NewVecVT = MVT::getVectorVT(NewEVT, NumElts*2);
325  SDValue NewVec = DAG.getNode(ISD::BIT_CONVERT, dl,
326                               NewVecVT, N->getOperand(0));
327
328  SDValue Lo, Hi;
329  GetExpandedOp(Val, Lo, Hi);
330  if (TLI.isBigEndian())
331    std::swap(Lo, Hi);
332
333  SDValue Idx = N->getOperand(2);
334  Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx, Idx);
335  NewVec = DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, NewVecVT, NewVec, Lo, Idx);
336  Idx = DAG.getNode(ISD::ADD, dl,
337                    Idx.getValueType(), Idx, DAG.getIntPtrConstant(1));
338  NewVec =  DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, NewVecVT, NewVec, Hi, Idx);
339
340  // Convert the new vector to the old vector type.
341  return DAG.getNode(ISD::BIT_CONVERT, dl, VecVT, NewVec);
342}
343
344SDValue DAGTypeLegalizer::ExpandOp_SCALAR_TO_VECTOR(SDNode *N) {
345  DebugLoc dl = N->getDebugLoc();
346  MVT VT = N->getValueType(0);
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