LegalizeTypes.h revision 4ac8ecc756bd6829ca06c4289548d3eed31c3fa7 
1//===-- LegalizeTypes.h - Definition of the DAG Type Legalizer class ------===//
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 defines the DAGTypeLegalizer class.  This is a private interface
11// shared between the code that implements the SelectionDAG::LegalizeTypes
12// method.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef SELECTIONDAG_LEGALIZETYPES_H
17#define SELECTIONDAG_LEGALIZETYPES_H
18
19#define DEBUG_TYPE "legalize-types"
20#include "llvm/CodeGen/SelectionDAG.h"
21#include "llvm/Target/TargetLowering.h"
22#include "llvm/ADT/DenseMap.h"
23#include "llvm/Support/Compiler.h"
24#include "llvm/Support/Debug.h"
25
26namespace llvm {
27
28//===----------------------------------------------------------------------===//
29/// DAGTypeLegalizer - This takes an arbitrary SelectionDAG as input and
30/// hacks on it until the target machine can handle it.  This involves
31/// eliminating value sizes the machine cannot handle (promoting small sizes to
32/// large sizes or splitting up large values into small values) as well as
33/// eliminating operations the machine cannot handle.
34///
35/// This code also does a small amount of optimization and recognition of idioms
36/// as part of its processing.  For example, if a target does not support a
37/// 'setcc' instruction efficiently, but does support 'brcc' instruction, this
38/// will attempt merge setcc and brc instructions into brcc's.
39///
40class VISIBILITY_HIDDEN DAGTypeLegalizer {
41  TargetLowering &TLI;
42  SelectionDAG &DAG;
43public:
44  // NodeIDFlags - This pass uses the NodeID on the SDNodes to hold information
45  // about the state of the node.  The enum has all the values.
46  enum NodeIDFlags {
47    /// ReadyToProcess - All operands have been processed, so this node is ready
48    /// to be handled.
49    ReadyToProcess = 0,
50
51    /// NewNode - This is a new node that was created in the process of
52    /// legalizing some other node.
53    NewNode = -1,
54
55    /// Processed - This is a node that has already been processed.
56    Processed = -2
57
58    // 1+ - This is a node which has this many unlegalized operands.
59  };
60private:
61  enum LegalizeAction {
62    Legal,      // The target natively supports this type.
63    Promote,    // This type should be executed in a larger type.
64    Expand,     // This type should be split into two types of half the size.
65    FloatToInt, // Convert a floating point type to an integer of the same size.
66    Scalarize,  // Replace this one-element vector type with its element type.
67    Split       // This vector type should be split into smaller vectors.
68  };
69
70  /// ValueTypeActions - This is a bitvector that contains two bits for each
71  /// simple value type, where the two bits correspond to the LegalizeAction
72  /// enum from TargetLowering.  This can be queried with "getTypeAction(VT)".
73  TargetLowering::ValueTypeActionImpl ValueTypeActions;
74
75  /// getTypeAction - Return how we should legalize values of this type, either
76  /// it is already legal, or we need to promote it to a larger integer type, or
77  /// we need to expand it into multiple registers of a smaller integer type, or
78  /// we need to scalarize a one-element vector type into the element type, or
79  /// we need to split a vector type into smaller vector types.
80  LegalizeAction getTypeAction(MVT::ValueType VT) const {
81    switch (ValueTypeActions.getTypeAction(VT)) {
82    default:
83      assert(false && "Unknown legalize action!");
84    case TargetLowering::Legal:
85      return Legal;
86    case TargetLowering::Promote:
87      return Promote;
88    case TargetLowering::Expand:
89      // Expand can mean
90      // 1) split scalar in half, 2) convert a float to an integer,
91      // 3) scalarize a single-element vector, 4) split a vector in two.
92      if (!MVT::isVector(VT)) {
93        if (MVT::getSizeInBits(VT) ==
94            MVT::getSizeInBits(TLI.getTypeToTransformTo(VT)))
95          return FloatToInt;
96        else
97          return Expand;
98      } else if (MVT::getVectorNumElements(VT) == 1) {
99        return Scalarize;
100      } else {
101        return Split;
102      }
103    }
104  }
105
106  /// isTypeLegal - Return true if this type is legal on this target.
107  bool isTypeLegal(MVT::ValueType VT) const {
108    return ValueTypeActions.getTypeAction(VT) == TargetLowering::Legal;
109  }
110
111  /// PromotedNodes - For nodes that are below legal width, this map indicates
112  /// what promoted value to use.
113  DenseMap<SDOperandImpl, SDOperand> PromotedNodes;
114
115  /// ExpandedNodes - For nodes that need to be expanded this map indicates
116  /// which operands are the expanded version of the input.
117  DenseMap<SDOperandImpl, std::pair<SDOperand, SDOperand> > ExpandedNodes;
118
119  /// FloatToIntedNodes - For floating point nodes converted to integers of
120  /// the same size, this map indicates the converted value to use.
121  DenseMap<SDOperandImpl, SDOperand> FloatToIntedNodes;
122
123  /// ScalarizedNodes - For nodes that are <1 x ty>, this map indicates the
124  /// scalar value of type 'ty' to use.
125  DenseMap<SDOperandImpl, SDOperand> ScalarizedNodes;
126
127  /// SplitNodes - For nodes that need to be split this map indicates
128  /// which operands are the expanded version of the input.
129  DenseMap<SDOperandImpl, std::pair<SDOperand, SDOperand> > SplitNodes;
130
131  /// ReplacedNodes - For nodes that have been replaced with another,
132  /// indicates the replacement node to use.
133  DenseMap<SDOperandImpl, SDOperand> ReplacedNodes;
134
135  /// Worklist - This defines a worklist of nodes to process.  In order to be
136  /// pushed onto this worklist, all operands of a node must have already been
137  /// processed.
138  SmallVector<SDNode*, 128> Worklist;
139
140public:
141  explicit DAGTypeLegalizer(SelectionDAG &dag)
142    : TLI(dag.getTargetLoweringInfo()), DAG(dag),
143    ValueTypeActions(TLI.getValueTypeActions()) {
144    assert(MVT::LAST_VALUETYPE <= 32 &&
145           "Too many value types for ValueTypeActions to hold!");
146  }
147
148  void run();
149
150  /// ReanalyzeNode - Recompute the NodeID and correct processed operands
151  /// for the specified node, adding it to the worklist if ready.
152  void ReanalyzeNode(SDNode *N) {
153    N->setNodeId(NewNode);
154    AnalyzeNewNode(N);
155  }
156
157private:
158  void AnalyzeNewNode(SDNode *&N);
159
160  void ReplaceValueWith(SDOperand From, SDOperand To);
161  void ReplaceNodeWith(SDNode *From, SDNode *To);
162
163  void RemapNode(SDOperand &N);
164
165  // Common routines.
166  SDOperand BitConvertToInteger(SDOperand Op);
167  SDOperand CreateStackStoreLoad(SDOperand Op, MVT::ValueType DestVT);
168  SDOperand JoinIntegers(SDOperand Lo, SDOperand Hi);
169  void SplitInteger(SDOperand Op, SDOperand &Lo, SDOperand &Hi);
170  void SplitInteger(SDOperand Op, MVT::ValueType LoVT, MVT::ValueType HiVT,
171                    SDOperand &Lo, SDOperand &Hi);
172
173  //===--------------------------------------------------------------------===//
174  // Promotion Support: LegalizeTypesPromote.cpp
175  //===--------------------------------------------------------------------===//
176
177  SDOperand GetPromotedOp(SDOperand Op) {
178    SDOperand &PromotedOp = PromotedNodes[Op];
179    RemapNode(PromotedOp);
180    assert(PromotedOp.Val && "Operand wasn't promoted?");
181    return PromotedOp;
182  }
183  void SetPromotedOp(SDOperand Op, SDOperand Result);
184
185  /// GetPromotedZExtOp - Get a promoted operand and zero extend it to the final
186  /// size.
187  SDOperand GetPromotedZExtOp(SDOperand Op) {
188    MVT::ValueType OldVT = Op.getValueType();
189    Op = GetPromotedOp(Op);
190    return DAG.getZeroExtendInReg(Op, OldVT);
191  }
192
193  // Result Promotion.
194  void PromoteResult(SDNode *N, unsigned ResNo);
195  SDOperand PromoteResult_BIT_CONVERT(SDNode *N);
196  SDOperand PromoteResult_BUILD_PAIR(SDNode *N);
197  SDOperand PromoteResult_Constant(SDNode *N);
198  SDOperand PromoteResult_CTLZ(SDNode *N);
199  SDOperand PromoteResult_CTPOP(SDNode *N);
200  SDOperand PromoteResult_CTTZ(SDNode *N);
201  SDOperand PromoteResult_EXTRACT_VECTOR_ELT(SDNode *N);
202  SDOperand PromoteResult_FP_ROUND(SDNode *N);
203  SDOperand PromoteResult_FP_TO_XINT(SDNode *N);
204  SDOperand PromoteResult_INT_EXTEND(SDNode *N);
205  SDOperand PromoteResult_LOAD(LoadSDNode *N);
206  SDOperand PromoteResult_SDIV(SDNode *N);
207  SDOperand PromoteResult_SELECT   (SDNode *N);
208  SDOperand PromoteResult_SELECT_CC(SDNode *N);
209  SDOperand PromoteResult_SETCC(SDNode *N);
210  SDOperand PromoteResult_SHL(SDNode *N);
211  SDOperand PromoteResult_SimpleIntBinOp(SDNode *N);
212  SDOperand PromoteResult_SRA(SDNode *N);
213  SDOperand PromoteResult_SRL(SDNode *N);
214  SDOperand PromoteResult_TRUNCATE(SDNode *N);
215  SDOperand PromoteResult_UDIV(SDNode *N);
216  SDOperand PromoteResult_UNDEF(SDNode *N);
217
218  // Operand Promotion.
219  bool PromoteOperand(SDNode *N, unsigned OperandNo);
220  SDOperand PromoteOperand_ANY_EXTEND(SDNode *N);
221  SDOperand PromoteOperand_BUILD_PAIR(SDNode *N);
222  SDOperand PromoteOperand_BR_CC(SDNode *N, unsigned OpNo);
223  SDOperand PromoteOperand_BRCOND(SDNode *N, unsigned OpNo);
224  SDOperand PromoteOperand_BUILD_VECTOR(SDNode *N);
225  SDOperand PromoteOperand_FP_EXTEND(SDNode *N);
226  SDOperand PromoteOperand_FP_ROUND(SDNode *N);
227  SDOperand PromoteOperand_INT_TO_FP(SDNode *N);
228  SDOperand PromoteOperand_INSERT_VECTOR_ELT(SDNode *N, unsigned OpNo);
229  SDOperand PromoteOperand_MEMBARRIER(SDNode *N);
230  SDOperand PromoteOperand_RET(SDNode *N, unsigned OpNo);
231  SDOperand PromoteOperand_SELECT(SDNode *N, unsigned OpNo);
232  SDOperand PromoteOperand_SETCC(SDNode *N, unsigned OpNo);
233  SDOperand PromoteOperand_SIGN_EXTEND(SDNode *N);
234  SDOperand PromoteOperand_STORE(StoreSDNode *N, unsigned OpNo);
235  SDOperand PromoteOperand_TRUNCATE(SDNode *N);
236  SDOperand PromoteOperand_ZERO_EXTEND(SDNode *N);
237
238  void PromoteSetCCOperands(SDOperand &LHS,SDOperand &RHS, ISD::CondCode Code);
239
240  //===--------------------------------------------------------------------===//
241  // Expansion Support: LegalizeTypesExpand.cpp
242  //===--------------------------------------------------------------------===//
243
244  void GetExpandedOp(SDOperand Op, SDOperand &Lo, SDOperand &Hi);
245  void SetExpandedOp(SDOperand Op, SDOperand Lo, SDOperand Hi);
246
247  // Result Expansion.
248  void ExpandResult(SDNode *N, unsigned ResNo);
249  void ExpandResult_ANY_EXTEND (SDNode *N, SDOperand &Lo, SDOperand &Hi);
250  void ExpandResult_AssertZext (SDNode *N, SDOperand &Lo, SDOperand &Hi);
251  void ExpandResult_BIT_CONVERT(SDNode *N, SDOperand &Lo, SDOperand &Hi);
252  void ExpandResult_BUILD_PAIR (SDNode *N, SDOperand &Lo, SDOperand &Hi);
253  void ExpandResult_Constant   (SDNode *N, SDOperand &Lo, SDOperand &Hi);
254  void ExpandResult_CTLZ       (SDNode *N, SDOperand &Lo, SDOperand &Hi);
255  void ExpandResult_CTPOP      (SDNode *N, SDOperand &Lo, SDOperand &Hi);
256  void ExpandResult_CTTZ       (SDNode *N, SDOperand &Lo, SDOperand &Hi);
257  void ExpandResult_EXTRACT_VECTOR_ELT(SDNode *N, SDOperand &Lo, SDOperand &Hi);
258  void ExpandResult_LOAD       (LoadSDNode *N, SDOperand &Lo, SDOperand &Hi);
259  void ExpandResult_MERGE_VALUES(SDNode *N, SDOperand &Lo, SDOperand &Hi);
260  void ExpandResult_SIGN_EXTEND(SDNode *N, SDOperand &Lo, SDOperand &Hi);
261  void ExpandResult_SIGN_EXTEND_INREG(SDNode *N, SDOperand &Lo, SDOperand &Hi);
262  void ExpandResult_TRUNCATE   (SDNode *N, SDOperand &Lo, SDOperand &Hi);
263  void ExpandResult_UNDEF      (SDNode *N, SDOperand &Lo, SDOperand &Hi);
264  void ExpandResult_ZERO_EXTEND(SDNode *N, SDOperand &Lo, SDOperand &Hi);
265
266  void ExpandResult_Logical    (SDNode *N, SDOperand &Lo, SDOperand &Hi);
267  void ExpandResult_BSWAP      (SDNode *N, SDOperand &Lo, SDOperand &Hi);
268  void ExpandResult_ADDSUB     (SDNode *N, SDOperand &Lo, SDOperand &Hi);
269  void ExpandResult_ADDSUBC    (SDNode *N, SDOperand &Lo, SDOperand &Hi);
270  void ExpandResult_ADDSUBE    (SDNode *N, SDOperand &Lo, SDOperand &Hi);
271  void ExpandResult_SELECT     (SDNode *N, SDOperand &Lo, SDOperand &Hi);
272  void ExpandResult_SELECT_CC  (SDNode *N, SDOperand &Lo, SDOperand &Hi);
273  void ExpandResult_MUL        (SDNode *N, SDOperand &Lo, SDOperand &Hi);
274  void ExpandResult_Shift      (SDNode *N, SDOperand &Lo, SDOperand &Hi);
275
276  void ExpandShiftByConstant(SDNode *N, unsigned Amt,
277                             SDOperand &Lo, SDOperand &Hi);
278  bool ExpandShiftWithKnownAmountBit(SDNode *N, SDOperand &Lo, SDOperand &Hi);
279
280  // Operand Expansion.
281  bool ExpandOperand(SDNode *N, unsigned OperandNo);
282  SDOperand ExpandOperand_BIT_CONVERT(SDNode *N);
283  SDOperand ExpandOperand_BR_CC(SDNode *N);
284  SDOperand ExpandOperand_BUILD_VECTOR(SDNode *N);
285  SDOperand ExpandOperand_EXTRACT_ELEMENT(SDNode *N);
286  SDOperand ExpandOperand_SETCC(SDNode *N);
287  SDOperand ExpandOperand_SINT_TO_FP(SDOperand Source, MVT::ValueType DestTy);
288  SDOperand ExpandOperand_STORE(StoreSDNode *N, unsigned OpNo);
289  SDOperand ExpandOperand_TRUNCATE(SDNode *N);
290  SDOperand ExpandOperand_UINT_TO_FP(SDOperand Source, MVT::ValueType DestTy);
291
292  void ExpandSetCCOperands(SDOperand &NewLHS, SDOperand &NewRHS,
293                           ISD::CondCode &CCCode);
294
295  //===--------------------------------------------------------------------===//
296  // Float to Integer Conversion Support: LegalizeTypesFloatToInt.cpp
297  //===--------------------------------------------------------------------===//
298
299  SDOperand GetIntegerOp(SDOperand Op) {
300    SDOperand &IntegerOp = FloatToIntedNodes[Op];
301    RemapNode(IntegerOp);
302    assert(IntegerOp.Val && "Operand wasn't converted to integer?");
303    return IntegerOp;
304  }
305  void SetIntegerOp(SDOperand Op, SDOperand Result);
306
307  // Result Float to Integer Conversion.
308  void FloatToIntResult(SDNode *N, unsigned OpNo);
309  SDOperand FloatToIntRes_BIT_CONVERT(SDNode *N);
310  SDOperand FloatToIntRes_BUILD_PAIR(SDNode *N);
311  SDOperand FloatToIntRes_FCOPYSIGN(SDNode *N);
312  SDOperand FloatToIntRes_LOAD(SDNode *N);
313
314  // Operand Float to Integer Conversion.
315  bool FloatToIntOperand(SDNode *N, unsigned OpNo);
316  SDOperand FloatToIntOp_BIT_CONVERT(SDNode *N);
317
318  //===--------------------------------------------------------------------===//
319  // Scalarization Support: LegalizeTypesScalarize.cpp
320  //===--------------------------------------------------------------------===//
321
322  SDOperand GetScalarizedOp(SDOperand Op) {
323    SDOperand &ScalarOp = ScalarizedNodes[Op];
324    RemapNode(ScalarOp);
325    assert(ScalarOp.Val && "Operand wasn't scalarized?");
326    return ScalarOp;
327  }
328  void SetScalarizedOp(SDOperand Op, SDOperand Result);
329
330  // Result Vector Scalarization: <1 x ty> -> ty.
331  void ScalarizeResult(SDNode *N, unsigned OpNo);
332  SDOperand ScalarizeRes_BinOp(SDNode *N);
333  SDOperand ScalarizeRes_UnaryOp(SDNode *N);
334
335  SDOperand ScalarizeRes_BIT_CONVERT(SDNode *N);
336  SDOperand ScalarizeRes_FPOWI(SDNode *N);
337  SDOperand ScalarizeRes_INSERT_VECTOR_ELT(SDNode *N);
338  SDOperand ScalarizeRes_LOAD(LoadSDNode *N);
339  SDOperand ScalarizeRes_SELECT(SDNode *N);
340  SDOperand ScalarizeRes_UNDEF(SDNode *N);
341  SDOperand ScalarizeRes_VECTOR_SHUFFLE(SDNode *N);
342
343  // Operand Vector Scalarization: <1 x ty> -> ty.
344  bool ScalarizeOperand(SDNode *N, unsigned OpNo);
345  SDOperand ScalarizeOp_BIT_CONVERT(SDNode *N);
346  SDOperand ScalarizeOp_EXTRACT_VECTOR_ELT(SDNode *N);
347  SDOperand ScalarizeOp_STORE(StoreSDNode *N, unsigned OpNo);
348
349  //===--------------------------------------------------------------------===//
350  // Vector Splitting Support: LegalizeTypesSplit.cpp
351  //===--------------------------------------------------------------------===//
352
353  void GetSplitOp(SDOperand Op, SDOperand &Lo, SDOperand &Hi);
354  void SetSplitOp(SDOperand Op, SDOperand Lo, SDOperand Hi);
355
356  // Result Vector Splitting: <128 x ty> -> 2 x <64 x ty>.
357  void SplitResult(SDNode *N, unsigned OpNo);
358
359  void SplitRes_UNDEF(SDNode *N, SDOperand &Lo, SDOperand &Hi);
360  void SplitRes_LOAD(LoadSDNode *N, SDOperand &Lo, SDOperand &Hi);
361  void SplitRes_BUILD_PAIR(SDNode *N, SDOperand &Lo, SDOperand &Hi);
362  void SplitRes_INSERT_VECTOR_ELT(SDNode *N, SDOperand &Lo, SDOperand &Hi);
363  void SplitRes_VECTOR_SHUFFLE(SDNode *N, SDOperand &Lo, SDOperand &Hi);
364
365  void SplitRes_BUILD_VECTOR(SDNode *N, SDOperand &Lo, SDOperand &Hi);
366  void SplitRes_CONCAT_VECTORS(SDNode *N, SDOperand &Lo, SDOperand &Hi);
367  void SplitRes_BIT_CONVERT(SDNode *N, SDOperand &Lo, SDOperand &Hi);
368  void SplitRes_UnOp(SDNode *N, SDOperand &Lo, SDOperand &Hi);
369  void SplitRes_BinOp(SDNode *N, SDOperand &Lo, SDOperand &Hi);
370  void SplitRes_FPOWI(SDNode *N, SDOperand &Lo, SDOperand &Hi);
371  void SplitRes_SELECT(SDNode *N, SDOperand &Lo, SDOperand &Hi);
372
373  // Operand Vector Splitting: <128 x ty> -> 2 x <64 x ty>.
374  bool SplitOperand(SDNode *N, unsigned OpNo);
375
376  SDOperand SplitOp_BIT_CONVERT(SDNode *N);
377  SDOperand SplitOp_EXTRACT_SUBVECTOR(SDNode *N);
378  SDOperand SplitOp_EXTRACT_VECTOR_ELT(SDNode *N);
379  SDOperand SplitOp_RET(SDNode *N, unsigned OpNo);
380  SDOperand SplitOp_STORE(StoreSDNode *N, unsigned OpNo);
381  SDOperand SplitOp_VECTOR_SHUFFLE(SDNode *N, unsigned OpNo);
382
383public:
384  void SanityCheck(SDNode *N);
385};
386
387} // end namespace llvm.
388
389#endif
390