ConstantFold.cpp revision 0425a87a625de7f107642242c21eafb58c2119da 
1//===- ConstantHandling.cpp - Implement ConstantHandling.h ----------------===//
2//
3// This file implements the various intrinsic operations, on constant values.
4//
5//===----------------------------------------------------------------------===//
6
7#include "llvm/ConstantHandling.h"
8#include "llvm/iPHINode.h"
9#include "llvm/InstrTypes.h"
10#include "llvm/DerivedTypes.h"
11#include <cmath>
12
13AnnotationID ConstRules::AID(AnnotationManager::getID("opt::ConstRules",
14						      &ConstRules::find));
15
16// ConstantFoldInstruction - Attempt to constant fold the specified instruction.
17// If successful, the constant result is returned, if not, null is returned.
18//
19Constant *ConstantFoldInstruction(Instruction *I) {
20  if (PHINode *PN = dyn_cast<PHINode>(I)) {
21    if (PN->getNumIncomingValues() == 0)
22      return Constant::getNullValue(PN->getType());
23
24    Constant *Result = dyn_cast<Constant>(PN->getIncomingValue(0));
25    if (Result == 0) return 0;
26
27    // Handle PHI nodes specially here...
28    for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i)
29      if (PN->getIncomingValue(i) != Result)
30        return 0;   // Not all the same incoming constants...
31
32    // If we reach here, all incoming values are the same constant.
33    return Result;
34  }
35
36  Constant *Op0 = 0;
37  Constant *Op1 = 0;
38
39  if (I->getNumOperands() != 0) {    // Get first operand if it's a constant...
40    Op0 = dyn_cast<Constant>(I->getOperand(0));
41    if (Op0 == 0) return 0;          // Not a constant?, can't fold
42
43    if (I->getNumOperands() != 1) {  // Get second operand if it's a constant...
44      Op1 = dyn_cast<Constant>(I->getOperand(1));
45      if (Op1 == 0) return 0;        // Not a constant?, can't fold
46    }
47  }
48
49  if (isa<BinaryOperator>(I))
50    return ConstantExpr::get(I->getOpcode(), Op0, Op1);
51
52  switch (I->getOpcode()) {
53  case Instruction::Cast:
54    return ConstantExpr::getCast(Op0, I->getType());
55  case Instruction::Shl:
56  case Instruction::Shr:
57    return ConstantExpr::getShift(I->getOpcode(), Op0, Op1);
58  case Instruction::GetElementPtr: {
59    std::vector<Constant*> IdxList;
60    IdxList.reserve(I->getNumOperands()-1);
61    if (Op1) IdxList.push_back(Op1);
62    for (unsigned i = 2, e = I->getNumOperands(); i != e; ++i)
63      if (Constant *C = dyn_cast<Constant>(I->getOperand(i)))
64        IdxList.push_back(C);
65      else
66        return 0;  // Non-constant operand
67    return ConstantExpr::getGetElementPtr(Op0, IdxList);
68  }
69  default:
70    return 0;
71  }
72}
73
74static unsigned getSize(const Type *Ty) {
75  unsigned S = Ty->getPrimitiveSize();
76  return S ? S : 8;  // Treat pointers at 8 bytes
77}
78
79Constant *ConstantFoldCastInstruction(const Constant *V, const Type *DestTy) {
80  if (V->getType() == DestTy) return (Constant*)V;
81
82  if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
83    if (CE->getOpcode() == Instruction::Cast) {
84      Constant *Op = const_cast<Constant*>(CE->getOperand(0));
85      // Try to not produce a cast of a cast, which is almost always redundant.
86      if (!Op->getType()->isFloatingPoint() &&
87          !CE->getType()->isFloatingPoint() &&
88          !DestTy->getType()->isFloatingPoint()) {
89        unsigned S1 = getSize(Op->getType()), S2 = getSize(CE->getType());
90        unsigned S3 = getSize(DestTy);
91        if (Op->getType() == DestTy && S3 >= S2)
92          return Op;
93        if (S1 >= S2 && S2 >= S3)
94          return ConstantExpr::getCast(Op, DestTy);
95        if (S1 <= S2 && S2 >= S3 && S1 <= S3)
96          return ConstantExpr::getCast(Op, DestTy);
97      }
98    } else if (CE->getOpcode() == Instruction::GetElementPtr) {
99      // If all of the indexes in the GEP are null values, there is no pointer
100      // adjustment going on.  We might as well cast the source pointer.
101      bool isAllNull = true;
102      for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
103        if (!CE->getOperand(i)->isNullValue()) {
104          isAllNull = false;
105          break;
106        }
107      if (isAllNull)
108        return ConstantExpr::getCast(CE->getOperand(0), DestTy);
109    }
110
111  return ConstRules::get(*V, *V)->castTo(V, DestTy);
112}
113
114Constant *ConstantFoldBinaryInstruction(unsigned Opcode, const Constant *V1,
115                                        const Constant *V2) {
116  switch (Opcode) {
117  case Instruction::Add:     return *V1 + *V2;
118  case Instruction::Sub:     return *V1 - *V2;
119  case Instruction::Mul:     return *V1 * *V2;
120  case Instruction::Div:     return *V1 / *V2;
121  case Instruction::Rem:     return *V1 % *V2;
122  case Instruction::And:     return *V1 & *V2;
123  case Instruction::Or:      return *V1 | *V2;
124  case Instruction::Xor:     return *V1 ^ *V2;
125
126  case Instruction::SetEQ:   return *V1 == *V2;
127  case Instruction::SetNE:   return *V1 != *V2;
128  case Instruction::SetLE:   return *V1 <= *V2;
129  case Instruction::SetGE:   return *V1 >= *V2;
130  case Instruction::SetLT:   return *V1 <  *V2;
131  case Instruction::SetGT:   return *V1 >  *V2;
132  }
133  return 0;
134}
135
136Constant *ConstantFoldShiftInstruction(unsigned Opcode, const Constant *V1,
137                                       const Constant *V2) {
138  switch (Opcode) {
139  case Instruction::Shl:     return *V1 << *V2;
140  case Instruction::Shr:     return *V1 >> *V2;
141  default:                   return 0;
142  }
143}
144
145Constant *ConstantFoldGetElementPtr(const Constant *C,
146                                    const std::vector<Constant*> &IdxList) {
147  if (IdxList.size() == 0 ||
148      (IdxList.size() == 1 && IdxList[0]->isNullValue()))
149    return const_cast<Constant*>(C);
150
151  // TODO If C is null and all idx's are null, return null of the right type.
152
153
154  if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
155    // Combine Indices - If the source pointer to this getelementptr instruction
156    // is a getelementptr instruction, combine the indices of the two
157    // getelementptr instructions into a single instruction.
158    //
159    if (CE->getOpcode() == Instruction::GetElementPtr) {
160      if (CE->getOperand(CE->getNumOperands()-1)->getType() == Type::LongTy) {
161        std::vector<Constant*> NewIndices;
162        NewIndices.reserve(IdxList.size() + CE->getNumOperands());
163        for (unsigned i = 1, e = CE->getNumOperands()-1; i != e; ++i)
164          NewIndices.push_back(cast<Constant>(CE->getOperand(i)));
165
166        // Add the last index of the source with the first index of the new GEP.
167        Constant *Combined =
168          ConstantExpr::get(Instruction::Add, IdxList[0],
169                            CE->getOperand(CE->getNumOperands()-1));
170
171        NewIndices.push_back(Combined);
172        NewIndices.insert(NewIndices.end(), IdxList.begin()+1, IdxList.end());
173        return ConstantExpr::getGetElementPtr(CE->getOperand(0), NewIndices);
174      }
175    }
176
177    // Implement folding of:
178    //    int* getelementptr ([2 x int]* cast ([3 x int]* %X to [2 x int]*),
179    //                        long 0, long 0)
180    // To: int* getelementptr ([3 x int]* %X, long 0, long 0)
181    //
182    if (CE->getOpcode() == Instruction::Cast && IdxList.size() > 1 &&
183        IdxList[0]->isNullValue())
184      if (const PointerType *SPT =
185          dyn_cast<PointerType>(CE->getOperand(0)->getType()))
186        if (const ArrayType *SAT = dyn_cast<ArrayType>(SPT->getElementType()))
187          if (const ArrayType *CAT =
188              dyn_cast<ArrayType>(cast<PointerType>(C->getType())->getElementType()))
189            if (CAT->getElementType() == SAT->getElementType())
190              return ConstantExpr::getGetElementPtr(
191                      (Constant*)CE->getOperand(0), IdxList);
192  }
193  return 0;
194}
195
196
197//===----------------------------------------------------------------------===//
198//                             TemplateRules Class
199//===----------------------------------------------------------------------===//
200//
201// TemplateRules - Implement a subclass of ConstRules that provides all
202// operations as noops.  All other rules classes inherit from this class so
203// that if functionality is needed in the future, it can simply be added here
204// and to ConstRules without changing anything else...
205//
206// This class also provides subclasses with typesafe implementations of methods
207// so that don't have to do type casting.
208//
209template<class ArgType, class SubClassName>
210class TemplateRules : public ConstRules {
211
212  //===--------------------------------------------------------------------===//
213  // Redirecting functions that cast to the appropriate types
214  //===--------------------------------------------------------------------===//
215
216  virtual Constant *add(const Constant *V1, const Constant *V2) const {
217    return SubClassName::Add((const ArgType *)V1, (const ArgType *)V2);
218  }
219  virtual Constant *sub(const Constant *V1, const Constant *V2) const {
220    return SubClassName::Sub((const ArgType *)V1, (const ArgType *)V2);
221  }
222  virtual Constant *mul(const Constant *V1, const Constant *V2) const {
223    return SubClassName::Mul((const ArgType *)V1, (const ArgType *)V2);
224  }
225  virtual Constant *div(const Constant *V1, const Constant *V2) const {
226    return SubClassName::Div((const ArgType *)V1, (const ArgType *)V2);
227  }
228  virtual Constant *rem(const Constant *V1, const Constant *V2) const {
229    return SubClassName::Rem((const ArgType *)V1, (const ArgType *)V2);
230  }
231  virtual Constant *op_and(const Constant *V1, const Constant *V2) const {
232    return SubClassName::And((const ArgType *)V1, (const ArgType *)V2);
233  }
234  virtual Constant *op_or(const Constant *V1, const Constant *V2) const {
235    return SubClassName::Or((const ArgType *)V1, (const ArgType *)V2);
236  }
237  virtual Constant *op_xor(const Constant *V1, const Constant *V2) const {
238    return SubClassName::Xor((const ArgType *)V1, (const ArgType *)V2);
239  }
240  virtual Constant *shl(const Constant *V1, const Constant *V2) const {
241    return SubClassName::Shl((const ArgType *)V1, (const ArgType *)V2);
242  }
243  virtual Constant *shr(const Constant *V1, const Constant *V2) const {
244    return SubClassName::Shr((const ArgType *)V1, (const ArgType *)V2);
245  }
246
247  virtual ConstantBool *lessthan(const Constant *V1,
248                                 const Constant *V2) const {
249    return SubClassName::LessThan((const ArgType *)V1, (const ArgType *)V2);
250  }
251
252  // Casting operators.  ick
253  virtual ConstantBool *castToBool(const Constant *V) const {
254    return SubClassName::CastToBool((const ArgType*)V);
255  }
256  virtual ConstantSInt *castToSByte(const Constant *V) const {
257    return SubClassName::CastToSByte((const ArgType*)V);
258  }
259  virtual ConstantUInt *castToUByte(const Constant *V) const {
260    return SubClassName::CastToUByte((const ArgType*)V);
261  }
262  virtual ConstantSInt *castToShort(const Constant *V) const {
263    return SubClassName::CastToShort((const ArgType*)V);
264  }
265  virtual ConstantUInt *castToUShort(const Constant *V) const {
266    return SubClassName::CastToUShort((const ArgType*)V);
267  }
268  virtual ConstantSInt *castToInt(const Constant *V) const {
269    return SubClassName::CastToInt((const ArgType*)V);
270  }
271  virtual ConstantUInt *castToUInt(const Constant *V) const {
272    return SubClassName::CastToUInt((const ArgType*)V);
273  }
274  virtual ConstantSInt *castToLong(const Constant *V) const {
275    return SubClassName::CastToLong((const ArgType*)V);
276  }
277  virtual ConstantUInt *castToULong(const Constant *V) const {
278    return SubClassName::CastToULong((const ArgType*)V);
279  }
280  virtual ConstantFP   *castToFloat(const Constant *V) const {
281    return SubClassName::CastToFloat((const ArgType*)V);
282  }
283  virtual ConstantFP   *castToDouble(const Constant *V) const {
284    return SubClassName::CastToDouble((const ArgType*)V);
285  }
286  virtual Constant *castToPointer(const Constant *V,
287                                  const PointerType *Ty) const {
288    return SubClassName::CastToPointer((const ArgType*)V, Ty);
289  }
290
291  //===--------------------------------------------------------------------===//
292  // Default "noop" implementations
293  //===--------------------------------------------------------------------===//
294
295  static Constant *Add(const ArgType *V1, const ArgType *V2) { return 0; }
296  static Constant *Sub(const ArgType *V1, const ArgType *V2) { return 0; }
297  static Constant *Mul(const ArgType *V1, const ArgType *V2) { return 0; }
298  static Constant *Div(const ArgType *V1, const ArgType *V2) { return 0; }
299  static Constant *Rem(const ArgType *V1, const ArgType *V2) { return 0; }
300  static Constant *And(const ArgType *V1, const ArgType *V2) { return 0; }
301  static Constant *Or (const ArgType *V1, const ArgType *V2) { return 0; }
302  static Constant *Xor(const ArgType *V1, const ArgType *V2) { return 0; }
303  static Constant *Shl(const ArgType *V1, const ArgType *V2) { return 0; }
304  static Constant *Shr(const ArgType *V1, const ArgType *V2) { return 0; }
305  static ConstantBool *LessThan(const ArgType *V1, const ArgType *V2) {
306    return 0;
307  }
308
309  // Casting operators.  ick
310  static ConstantBool *CastToBool  (const Constant *V) { return 0; }
311  static ConstantSInt *CastToSByte (const Constant *V) { return 0; }
312  static ConstantUInt *CastToUByte (const Constant *V) { return 0; }
313  static ConstantSInt *CastToShort (const Constant *V) { return 0; }
314  static ConstantUInt *CastToUShort(const Constant *V) { return 0; }
315  static ConstantSInt *CastToInt   (const Constant *V) { return 0; }
316  static ConstantUInt *CastToUInt  (const Constant *V) { return 0; }
317  static ConstantSInt *CastToLong  (const Constant *V) { return 0; }
318  static ConstantUInt *CastToULong (const Constant *V) { return 0; }
319  static ConstantFP   *CastToFloat (const Constant *V) { return 0; }
320  static ConstantFP   *CastToDouble(const Constant *V) { return 0; }
321  static Constant     *CastToPointer(const Constant *,
322                                     const PointerType *) {return 0;}
323};
324
325
326
327//===----------------------------------------------------------------------===//
328//                             EmptyRules Class
329//===----------------------------------------------------------------------===//
330//
331// EmptyRules provides a concrete base class of ConstRules that does nothing
332//
333struct EmptyRules : public TemplateRules<Constant, EmptyRules> {
334};
335
336
337
338//===----------------------------------------------------------------------===//
339//                              BoolRules Class
340//===----------------------------------------------------------------------===//
341//
342// BoolRules provides a concrete base class of ConstRules for the 'bool' type.
343//
344struct BoolRules : public TemplateRules<ConstantBool, BoolRules> {
345
346  static ConstantBool *LessThan(const ConstantBool *V1, const ConstantBool *V2){
347    return ConstantBool::get(V1->getValue() < V2->getValue());
348  }
349
350  static Constant *And(const ConstantBool *V1, const ConstantBool *V2) {
351    return ConstantBool::get(V1->getValue() & V2->getValue());
352  }
353
354  static Constant *Or(const ConstantBool *V1, const ConstantBool *V2) {
355    return ConstantBool::get(V1->getValue() | V2->getValue());
356  }
357
358  static Constant *Xor(const ConstantBool *V1, const ConstantBool *V2) {
359    return ConstantBool::get(V1->getValue() ^ V2->getValue());
360  }
361
362  // Casting operators.  ick
363#define DEF_CAST(TYPE, CLASS, CTYPE) \
364  static CLASS *CastTo##TYPE  (const ConstantBool *V) {    \
365    return CLASS::get(Type::TYPE##Ty, (CTYPE)(bool)V->getValue()); \
366  }
367
368  DEF_CAST(Bool  , ConstantBool, bool)
369  DEF_CAST(SByte , ConstantSInt, signed char)
370  DEF_CAST(UByte , ConstantUInt, unsigned char)
371  DEF_CAST(Short , ConstantSInt, signed short)
372  DEF_CAST(UShort, ConstantUInt, unsigned short)
373  DEF_CAST(Int   , ConstantSInt, signed int)
374  DEF_CAST(UInt  , ConstantUInt, unsigned int)
375  DEF_CAST(Long  , ConstantSInt, int64_t)
376  DEF_CAST(ULong , ConstantUInt, uint64_t)
377  DEF_CAST(Float , ConstantFP  , float)
378  DEF_CAST(Double, ConstantFP  , double)
379#undef DEF_CAST
380};
381
382
383//===----------------------------------------------------------------------===//
384//                            PointerRules Class
385//===----------------------------------------------------------------------===//
386//
387// PointerRules provides a concrete base class of ConstRules for pointer types
388//
389struct PointerRules : public TemplateRules<ConstantPointer, PointerRules> {
390  static ConstantBool *CastToBool  (const Constant *V) {
391    if (V->isNullValue()) return ConstantBool::False;
392    return 0;  // Can't const prop other types of pointers
393  }
394  static ConstantSInt *CastToSByte (const Constant *V) {
395    if (V->isNullValue()) return ConstantSInt::get(Type::SByteTy, 0);
396    return 0;  // Can't const prop other types of pointers
397  }
398  static ConstantUInt *CastToUByte (const Constant *V) {
399    if (V->isNullValue()) return ConstantUInt::get(Type::UByteTy, 0);
400    return 0;  // Can't const prop other types of pointers
401  }
402  static ConstantSInt *CastToShort (const Constant *V) {
403    if (V->isNullValue()) return ConstantSInt::get(Type::ShortTy, 0);
404    return 0;  // Can't const prop other types of pointers
405  }
406  static ConstantUInt *CastToUShort(const Constant *V) {
407    if (V->isNullValue()) return ConstantUInt::get(Type::UShortTy, 0);
408    return 0;  // Can't const prop other types of pointers
409  }
410  static ConstantSInt *CastToInt   (const Constant *V) {
411    if (V->isNullValue()) return ConstantSInt::get(Type::IntTy, 0);
412    return 0;  // Can't const prop other types of pointers
413  }
414  static ConstantUInt *CastToUInt  (const Constant *V) {
415    if (V->isNullValue()) return ConstantUInt::get(Type::UIntTy, 0);
416    return 0;  // Can't const prop other types of pointers
417  }
418  static ConstantSInt *CastToLong  (const Constant *V) {
419    if (V->isNullValue()) return ConstantSInt::get(Type::LongTy, 0);
420    return 0;  // Can't const prop other types of pointers
421  }
422  static ConstantUInt *CastToULong (const Constant *V) {
423    if (V->isNullValue()) return ConstantUInt::get(Type::ULongTy, 0);
424    return 0;  // Can't const prop other types of pointers
425  }
426  static ConstantFP   *CastToFloat (const Constant *V) {
427    if (V->isNullValue()) return ConstantFP::get(Type::FloatTy, 0);
428    return 0;  // Can't const prop other types of pointers
429  }
430  static ConstantFP   *CastToDouble(const Constant *V) {
431    if (V->isNullValue()) return ConstantFP::get(Type::DoubleTy, 0);
432    return 0;  // Can't const prop other types of pointers
433  }
434
435  static Constant *CastToPointer(const ConstantPointer *V,
436                                 const PointerType *PTy) {
437    if (V->getType() == PTy)
438      return const_cast<ConstantPointer*>(V);  // Allow cast %PTy %ptr to %PTy
439    if (V->isNullValue())
440      return ConstantPointerNull::get(PTy);
441    return 0;  // Can't const prop other types of pointers
442  }
443};
444
445
446//===----------------------------------------------------------------------===//
447//                             DirectRules Class
448//===----------------------------------------------------------------------===//
449//
450// DirectRules provides a concrete base classes of ConstRules for a variety of
451// different types.  This allows the C++ compiler to automatically generate our
452// constant handling operations in a typesafe and accurate manner.
453//
454template<class ConstantClass, class BuiltinType, Type **Ty, class SuperClass>
455struct DirectRules : public TemplateRules<ConstantClass, SuperClass> {
456  static Constant *Add(const ConstantClass *V1, const ConstantClass *V2) {
457    BuiltinType R = (BuiltinType)V1->getValue() + (BuiltinType)V2->getValue();
458    return ConstantClass::get(*Ty, R);
459  }
460
461  static Constant *Sub(const ConstantClass *V1, const ConstantClass *V2) {
462    BuiltinType R = (BuiltinType)V1->getValue() - (BuiltinType)V2->getValue();
463    return ConstantClass::get(*Ty, R);
464  }
465
466  static Constant *Mul(const ConstantClass *V1, const ConstantClass *V2) {
467    BuiltinType R = (BuiltinType)V1->getValue() * (BuiltinType)V2->getValue();
468    return ConstantClass::get(*Ty, R);
469  }
470
471  static Constant *Div(const ConstantClass *V1, const ConstantClass *V2) {
472    if (V2->isNullValue()) return 0;
473    BuiltinType R = (BuiltinType)V1->getValue() / (BuiltinType)V2->getValue();
474    return ConstantClass::get(*Ty, R);
475  }
476
477  static ConstantBool *LessThan(const ConstantClass *V1,
478                                const ConstantClass *V2) {
479    bool R = (BuiltinType)V1->getValue() < (BuiltinType)V2->getValue();
480    return ConstantBool::get(R);
481  }
482
483  static Constant *CastToPointer(const ConstantClass *V,
484                                 const PointerType *PTy) {
485    if (V->isNullValue())    // Is it a FP or Integral null value?
486      return ConstantPointerNull::get(PTy);
487    return 0;  // Can't const prop other types of pointers
488  }
489
490  // Casting operators.  ick
491#define DEF_CAST(TYPE, CLASS, CTYPE) \
492  static CLASS *CastTo##TYPE  (const ConstantClass *V) {    \
493    return CLASS::get(Type::TYPE##Ty, (CTYPE)(BuiltinType)V->getValue()); \
494  }
495
496  DEF_CAST(Bool  , ConstantBool, bool)
497  DEF_CAST(SByte , ConstantSInt, signed char)
498  DEF_CAST(UByte , ConstantUInt, unsigned char)
499  DEF_CAST(Short , ConstantSInt, signed short)
500  DEF_CAST(UShort, ConstantUInt, unsigned short)
501  DEF_CAST(Int   , ConstantSInt, signed int)
502  DEF_CAST(UInt  , ConstantUInt, unsigned int)
503  DEF_CAST(Long  , ConstantSInt, int64_t)
504  DEF_CAST(ULong , ConstantUInt, uint64_t)
505  DEF_CAST(Float , ConstantFP  , float)
506  DEF_CAST(Double, ConstantFP  , double)
507#undef DEF_CAST
508};
509
510
511//===----------------------------------------------------------------------===//
512//                           DirectIntRules Class
513//===----------------------------------------------------------------------===//
514//
515// DirectIntRules provides implementations of functions that are valid on
516// integer types, but not all types in general.
517//
518template <class ConstantClass, class BuiltinType, Type **Ty>
519struct DirectIntRules
520  : public DirectRules<ConstantClass, BuiltinType, Ty,
521                       DirectIntRules<ConstantClass, BuiltinType, Ty> > {
522
523  static Constant *Div(const ConstantClass *V1, const ConstantClass *V2) {
524    if (V2->isNullValue()) return 0;
525    if (V2->isAllOnesValue() &&              // MIN_INT / -1
526        (BuiltinType)V1->getValue() == -(BuiltinType)V1->getValue())
527      return 0;
528    BuiltinType R = (BuiltinType)V1->getValue() / (BuiltinType)V2->getValue();
529    return ConstantClass::get(*Ty, R);
530  }
531
532  static Constant *Rem(const ConstantClass *V1,
533                       const ConstantClass *V2) {
534    if (V2->isNullValue()) return 0;         // X / 0
535    if (V2->isAllOnesValue() &&              // MIN_INT / -1
536        (BuiltinType)V1->getValue() == -(BuiltinType)V1->getValue())
537      return 0;
538    BuiltinType R = (BuiltinType)V1->getValue() % (BuiltinType)V2->getValue();
539    return ConstantClass::get(*Ty, R);
540  }
541
542  static Constant *And(const ConstantClass *V1, const ConstantClass *V2) {
543    BuiltinType R = (BuiltinType)V1->getValue() & (BuiltinType)V2->getValue();
544    return ConstantClass::get(*Ty, R);
545  }
546  static Constant *Or(const ConstantClass *V1, const ConstantClass *V2) {
547    BuiltinType R = (BuiltinType)V1->getValue() | (BuiltinType)V2->getValue();
548    return ConstantClass::get(*Ty, R);
549  }
550  static Constant *Xor(const ConstantClass *V1, const ConstantClass *V2) {
551    BuiltinType R = (BuiltinType)V1->getValue() ^ (BuiltinType)V2->getValue();
552    return ConstantClass::get(*Ty, R);
553  }
554
555  static Constant *Shl(const ConstantClass *V1, const ConstantClass *V2) {
556    BuiltinType R = (BuiltinType)V1->getValue() << (BuiltinType)V2->getValue();
557    return ConstantClass::get(*Ty, R);
558  }
559
560  static Constant *Shr(const ConstantClass *V1, const ConstantClass *V2) {
561    BuiltinType R = (BuiltinType)V1->getValue() >> (BuiltinType)V2->getValue();
562    return ConstantClass::get(*Ty, R);
563  }
564};
565
566
567//===----------------------------------------------------------------------===//
568//                           DirectFPRules Class
569//===----------------------------------------------------------------------===//
570//
571// DirectFPRules provides implementations of functions that are valid on
572// floating point types, but not all types in general.
573//
574template <class ConstantClass, class BuiltinType, Type **Ty>
575struct DirectFPRules
576  : public DirectRules<ConstantClass, BuiltinType, Ty,
577                       DirectFPRules<ConstantClass, BuiltinType, Ty> > {
578  static Constant *Rem(const ConstantClass *V1, const ConstantClass *V2) {
579    if (V2->isNullValue()) return 0;
580    BuiltinType Result = std::fmod((BuiltinType)V1->getValue(),
581                                   (BuiltinType)V2->getValue());
582    return ConstantClass::get(*Ty, Result);
583  }
584};
585
586//===----------------------------------------------------------------------===//
587//                            DirectRules Subclasses
588//===----------------------------------------------------------------------===//
589//
590// Given the DirectRules class we can now implement lots of types with little
591// code.  Thank goodness C++ compilers are great at stomping out layers of
592// templates... can you imagine having to do this all by hand? (/me is lazy :)
593//
594
595// ConstRules::find - Return the constant rules that take care of the specified
596// type.
597//
598Annotation *ConstRules::find(AnnotationID AID, const Annotable *TyA, void *) {
599  assert(AID == ConstRules::AID && "Bad annotation for factory!");
600  const Type *Ty = cast<Type>((const Value*)TyA);
601
602  switch (Ty->getPrimitiveID()) {
603  case Type::BoolTyID:    return new BoolRules();
604  case Type::PointerTyID: return new PointerRules();
605  case Type::SByteTyID:
606    return new DirectIntRules<ConstantSInt,   signed char , &Type::SByteTy>();
607  case Type::UByteTyID:
608    return new DirectIntRules<ConstantUInt, unsigned char , &Type::UByteTy>();
609  case Type::ShortTyID:
610    return new DirectIntRules<ConstantSInt,   signed short, &Type::ShortTy>();
611  case Type::UShortTyID:
612    return new DirectIntRules<ConstantUInt, unsigned short, &Type::UShortTy>();
613  case Type::IntTyID:
614    return new DirectIntRules<ConstantSInt,   signed int  , &Type::IntTy>();
615  case Type::UIntTyID:
616    return new DirectIntRules<ConstantUInt, unsigned int  , &Type::UIntTy>();
617  case Type::LongTyID:
618    return new DirectIntRules<ConstantSInt,  int64_t      , &Type::LongTy>();
619  case Type::ULongTyID:
620    return new DirectIntRules<ConstantUInt, uint64_t      , &Type::ULongTy>();
621  case Type::FloatTyID:
622    return new DirectFPRules<ConstantFP  , float         , &Type::FloatTy>();
623  case Type::DoubleTyID:
624    return new DirectFPRules<ConstantFP  , double        , &Type::DoubleTy>();
625  default:
626    return new EmptyRules();
627  }
628}
629
630ConstRules *ConstRules::getConstantExprRules() {
631  static EmptyRules CERules;
632  return &CERules;
633}
634