1 //===- ConstantFolding.cpp - LLVM constant folder -------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements folding of constants for LLVM. This implements the
11 // (internal) ConstantFolding.h interface, which is used by the
12 // ConstantExpr::get* methods to automatically fold constants when possible.
14 // The current constant folding implementation is implemented in two pieces: the
15 // template-based folder for simple primitive constants like ConstantInt, and
16 // the special case hackery that we use to symbolically evaluate expressions
17 // that use ConstantExprs.
19 //===----------------------------------------------------------------------===//
21 #include "ConstantFolding.h"
22 #include "llvm/Constants.h"
23 #include "llvm/Instructions.h"
24 #include "llvm/DerivedTypes.h"
25 #include "llvm/Function.h"
26 #include "llvm/Support/Compiler.h"
27 #include "llvm/Support/GetElementPtrTypeIterator.h"
28 #include "llvm/Support/ManagedStatic.h"
29 #include "llvm/Support/MathExtras.h"
34 struct VISIBILITY_HIDDEN ConstRules {
36 virtual ~ConstRules() {}
38 // Binary Operators...
39 virtual Constant *add(const Constant *V1, const Constant *V2) const = 0;
40 virtual Constant *sub(const Constant *V1, const Constant *V2) const = 0;
41 virtual Constant *mul(const Constant *V1, const Constant *V2) const = 0;
42 virtual Constant *urem(const Constant *V1, const Constant *V2) const = 0;
43 virtual Constant *srem(const Constant *V1, const Constant *V2) const = 0;
44 virtual Constant *frem(const Constant *V1, const Constant *V2) const = 0;
45 virtual Constant *udiv(const Constant *V1, const Constant *V2) const = 0;
46 virtual Constant *sdiv(const Constant *V1, const Constant *V2) const = 0;
47 virtual Constant *fdiv(const Constant *V1, const Constant *V2) const = 0;
48 virtual Constant *op_and(const Constant *V1, const Constant *V2) const = 0;
49 virtual Constant *op_or (const Constant *V1, const Constant *V2) const = 0;
50 virtual Constant *op_xor(const Constant *V1, const Constant *V2) const = 0;
51 virtual Constant *shl(const Constant *V1, const Constant *V2) const = 0;
52 virtual Constant *lshr(const Constant *V1, const Constant *V2) const = 0;
53 virtual Constant *ashr(const Constant *V1, const Constant *V2) const = 0;
54 virtual Constant *lessthan(const Constant *V1, const Constant *V2) const =0;
55 virtual Constant *equalto(const Constant *V1, const Constant *V2) const = 0;
58 virtual Constant *castToBool (const Constant *V) const = 0;
59 virtual Constant *castToSByte (const Constant *V) const = 0;
60 virtual Constant *castToUByte (const Constant *V) const = 0;
61 virtual Constant *castToShort (const Constant *V) const = 0;
62 virtual Constant *castToUShort(const Constant *V) const = 0;
63 virtual Constant *castToInt (const Constant *V) const = 0;
64 virtual Constant *castToUInt (const Constant *V) const = 0;
65 virtual Constant *castToLong (const Constant *V) const = 0;
66 virtual Constant *castToULong (const Constant *V) const = 0;
67 virtual Constant *castToFloat (const Constant *V) const = 0;
68 virtual Constant *castToDouble(const Constant *V) const = 0;
69 virtual Constant *castToPointer(const Constant *V,
70 const PointerType *Ty) const = 0;
72 // ConstRules::get - Return an instance of ConstRules for the specified
75 static ConstRules &get(const Constant *V1, const Constant *V2);
77 ConstRules(const ConstRules &); // Do not implement
78 ConstRules &operator=(const ConstRules &); // Do not implement
83 //===----------------------------------------------------------------------===//
84 // TemplateRules Class
85 //===----------------------------------------------------------------------===//
87 // TemplateRules - Implement a subclass of ConstRules that provides all
88 // operations as noops. All other rules classes inherit from this class so
89 // that if functionality is needed in the future, it can simply be added here
90 // and to ConstRules without changing anything else...
92 // This class also provides subclasses with typesafe implementations of methods
93 // so that don't have to do type casting.
96 template<class ArgType, class SubClassName>
97 class VISIBILITY_HIDDEN TemplateRules : public ConstRules {
100 //===--------------------------------------------------------------------===//
101 // Redirecting functions that cast to the appropriate types
102 //===--------------------------------------------------------------------===//
104 virtual Constant *add(const Constant *V1, const Constant *V2) const {
105 return SubClassName::Add((const ArgType *)V1, (const ArgType *)V2);
107 virtual Constant *sub(const Constant *V1, const Constant *V2) const {
108 return SubClassName::Sub((const ArgType *)V1, (const ArgType *)V2);
110 virtual Constant *mul(const Constant *V1, const Constant *V2) const {
111 return SubClassName::Mul((const ArgType *)V1, (const ArgType *)V2);
113 virtual Constant *udiv(const Constant *V1, const Constant *V2) const {
114 return SubClassName::UDiv((const ArgType *)V1, (const ArgType *)V2);
116 virtual Constant *sdiv(const Constant *V1, const Constant *V2) const {
117 return SubClassName::SDiv((const ArgType *)V1, (const ArgType *)V2);
119 virtual Constant *fdiv(const Constant *V1, const Constant *V2) const {
120 return SubClassName::FDiv((const ArgType *)V1, (const ArgType *)V2);
122 virtual Constant *urem(const Constant *V1, const Constant *V2) const {
123 return SubClassName::URem((const ArgType *)V1, (const ArgType *)V2);
125 virtual Constant *srem(const Constant *V1, const Constant *V2) const {
126 return SubClassName::SRem((const ArgType *)V1, (const ArgType *)V2);
128 virtual Constant *frem(const Constant *V1, const Constant *V2) const {
129 return SubClassName::FRem((const ArgType *)V1, (const ArgType *)V2);
131 virtual Constant *op_and(const Constant *V1, const Constant *V2) const {
132 return SubClassName::And((const ArgType *)V1, (const ArgType *)V2);
134 virtual Constant *op_or(const Constant *V1, const Constant *V2) const {
135 return SubClassName::Or((const ArgType *)V1, (const ArgType *)V2);
137 virtual Constant *op_xor(const Constant *V1, const Constant *V2) const {
138 return SubClassName::Xor((const ArgType *)V1, (const ArgType *)V2);
140 virtual Constant *shl(const Constant *V1, const Constant *V2) const {
141 return SubClassName::Shl((const ArgType *)V1, (const ArgType *)V2);
143 virtual Constant *lshr(const Constant *V1, const Constant *V2) const {
144 return SubClassName::LShr((const ArgType *)V1, (const ArgType *)V2);
146 virtual Constant *ashr(const Constant *V1, const Constant *V2) const {
147 return SubClassName::AShr((const ArgType *)V1, (const ArgType *)V2);
150 virtual Constant *lessthan(const Constant *V1, const Constant *V2) const {
151 return SubClassName::LessThan((const ArgType *)V1, (const ArgType *)V2);
153 virtual Constant *equalto(const Constant *V1, const Constant *V2) const {
154 return SubClassName::EqualTo((const ArgType *)V1, (const ArgType *)V2);
157 // Casting operators. ick
158 virtual Constant *castToBool(const Constant *V) const {
159 return SubClassName::CastToBool((const ArgType*)V);
161 virtual Constant *castToSByte(const Constant *V) const {
162 return SubClassName::CastToSByte((const ArgType*)V);
164 virtual Constant *castToUByte(const Constant *V) const {
165 return SubClassName::CastToUByte((const ArgType*)V);
167 virtual Constant *castToShort(const Constant *V) const {
168 return SubClassName::CastToShort((const ArgType*)V);
170 virtual Constant *castToUShort(const Constant *V) const {
171 return SubClassName::CastToUShort((const ArgType*)V);
173 virtual Constant *castToInt(const Constant *V) const {
174 return SubClassName::CastToInt((const ArgType*)V);
176 virtual Constant *castToUInt(const Constant *V) const {
177 return SubClassName::CastToUInt((const ArgType*)V);
179 virtual Constant *castToLong(const Constant *V) const {
180 return SubClassName::CastToLong((const ArgType*)V);
182 virtual Constant *castToULong(const Constant *V) const {
183 return SubClassName::CastToULong((const ArgType*)V);
185 virtual Constant *castToFloat(const Constant *V) const {
186 return SubClassName::CastToFloat((const ArgType*)V);
188 virtual Constant *castToDouble(const Constant *V) const {
189 return SubClassName::CastToDouble((const ArgType*)V);
191 virtual Constant *castToPointer(const Constant *V,
192 const PointerType *Ty) const {
193 return SubClassName::CastToPointer((const ArgType*)V, Ty);
196 //===--------------------------------------------------------------------===//
197 // Default "noop" implementations
198 //===--------------------------------------------------------------------===//
200 static Constant *Add (const ArgType *V1, const ArgType *V2) { return 0; }
201 static Constant *Sub (const ArgType *V1, const ArgType *V2) { return 0; }
202 static Constant *Mul (const ArgType *V1, const ArgType *V2) { return 0; }
203 static Constant *SDiv(const ArgType *V1, const ArgType *V2) { return 0; }
204 static Constant *UDiv(const ArgType *V1, const ArgType *V2) { return 0; }
205 static Constant *FDiv(const ArgType *V1, const ArgType *V2) { return 0; }
206 static Constant *URem(const ArgType *V1, const ArgType *V2) { return 0; }
207 static Constant *SRem(const ArgType *V1, const ArgType *V2) { return 0; }
208 static Constant *FRem(const ArgType *V1, const ArgType *V2) { return 0; }
209 static Constant *And (const ArgType *V1, const ArgType *V2) { return 0; }
210 static Constant *Or (const ArgType *V1, const ArgType *V2) { return 0; }
211 static Constant *Xor (const ArgType *V1, const ArgType *V2) { return 0; }
212 static Constant *Shl (const ArgType *V1, const ArgType *V2) { return 0; }
213 static Constant *LShr(const ArgType *V1, const ArgType *V2) { return 0; }
214 static Constant *AShr(const ArgType *V1, const ArgType *V2) { return 0; }
215 static Constant *LessThan(const ArgType *V1, const ArgType *V2) {
218 static Constant *EqualTo(const ArgType *V1, const ArgType *V2) {
222 // Casting operators. ick
223 static Constant *CastToBool (const Constant *V) { return 0; }
224 static Constant *CastToSByte (const Constant *V) { return 0; }
225 static Constant *CastToUByte (const Constant *V) { return 0; }
226 static Constant *CastToShort (const Constant *V) { return 0; }
227 static Constant *CastToUShort(const Constant *V) { return 0; }
228 static Constant *CastToInt (const Constant *V) { return 0; }
229 static Constant *CastToUInt (const Constant *V) { return 0; }
230 static Constant *CastToLong (const Constant *V) { return 0; }
231 static Constant *CastToULong (const Constant *V) { return 0; }
232 static Constant *CastToFloat (const Constant *V) { return 0; }
233 static Constant *CastToDouble(const Constant *V) { return 0; }
234 static Constant *CastToPointer(const Constant *,
235 const PointerType *) {return 0;}
238 virtual ~TemplateRules() {}
240 } // end anonymous namespace
243 //===----------------------------------------------------------------------===//
245 //===----------------------------------------------------------------------===//
247 // EmptyRules provides a concrete base class of ConstRules that does nothing
250 struct VISIBILITY_HIDDEN EmptyRules
251 : public TemplateRules<Constant, EmptyRules> {
252 static Constant *EqualTo(const Constant *V1, const Constant *V2) {
253 if (V1 == V2) return ConstantBool::getTrue();
257 } // end anonymous namespace
261 //===----------------------------------------------------------------------===//
263 //===----------------------------------------------------------------------===//
265 // BoolRules provides a concrete base class of ConstRules for the 'bool' type.
268 struct VISIBILITY_HIDDEN BoolRules
269 : public TemplateRules<ConstantBool, BoolRules> {
271 static Constant *LessThan(const ConstantBool *V1, const ConstantBool *V2) {
272 return ConstantBool::get(V1->getValue() < V2->getValue());
275 static Constant *EqualTo(const Constant *V1, const Constant *V2) {
276 return ConstantBool::get(V1 == V2);
279 static Constant *And(const ConstantBool *V1, const ConstantBool *V2) {
280 return ConstantBool::get(V1->getValue() & V2->getValue());
283 static Constant *Or(const ConstantBool *V1, const ConstantBool *V2) {
284 return ConstantBool::get(V1->getValue() | V2->getValue());
287 static Constant *Xor(const ConstantBool *V1, const ConstantBool *V2) {
288 return ConstantBool::get(V1->getValue() ^ V2->getValue());
291 // Casting operators. ick
292 #define DEF_CAST(TYPE, CLASS, CTYPE) \
293 static Constant *CastTo##TYPE (const ConstantBool *V) { \
294 return CLASS::get(Type::TYPE##Ty, (CTYPE)(bool)V->getValue()); \
297 DEF_CAST(Bool , ConstantBool, bool)
298 DEF_CAST(SByte , ConstantInt, signed char)
299 DEF_CAST(UByte , ConstantInt, unsigned char)
300 DEF_CAST(Short , ConstantInt, signed short)
301 DEF_CAST(UShort, ConstantInt, unsigned short)
302 DEF_CAST(Int , ConstantInt, signed int)
303 DEF_CAST(UInt , ConstantInt, unsigned int)
304 DEF_CAST(Long , ConstantInt, int64_t)
305 DEF_CAST(ULong , ConstantInt, uint64_t)
306 DEF_CAST(Float , ConstantFP , float)
307 DEF_CAST(Double, ConstantFP , double)
310 } // end anonymous namespace
313 //===----------------------------------------------------------------------===//
314 // NullPointerRules Class
315 //===----------------------------------------------------------------------===//
317 // NullPointerRules provides a concrete base class of ConstRules for null
321 struct VISIBILITY_HIDDEN NullPointerRules
322 : public TemplateRules<ConstantPointerNull, NullPointerRules> {
323 static Constant *EqualTo(const Constant *V1, const Constant *V2) {
324 return ConstantBool::getTrue(); // Null pointers are always equal
326 static Constant *CastToBool(const Constant *V) {
327 return ConstantBool::getFalse();
329 static Constant *CastToSByte (const Constant *V) {
330 return ConstantInt::get(Type::SByteTy, 0);
332 static Constant *CastToUByte (const Constant *V) {
333 return ConstantInt::get(Type::UByteTy, 0);
335 static Constant *CastToShort (const Constant *V) {
336 return ConstantInt::get(Type::ShortTy, 0);
338 static Constant *CastToUShort(const Constant *V) {
339 return ConstantInt::get(Type::UShortTy, 0);
341 static Constant *CastToInt (const Constant *V) {
342 return ConstantInt::get(Type::IntTy, 0);
344 static Constant *CastToUInt (const Constant *V) {
345 return ConstantInt::get(Type::UIntTy, 0);
347 static Constant *CastToLong (const Constant *V) {
348 return ConstantInt::get(Type::LongTy, 0);
350 static Constant *CastToULong (const Constant *V) {
351 return ConstantInt::get(Type::ULongTy, 0);
353 static Constant *CastToFloat (const Constant *V) {
354 return ConstantFP::get(Type::FloatTy, 0);
356 static Constant *CastToDouble(const Constant *V) {
357 return ConstantFP::get(Type::DoubleTy, 0);
360 static Constant *CastToPointer(const ConstantPointerNull *V,
361 const PointerType *PTy) {
362 return ConstantPointerNull::get(PTy);
365 } // end anonymous namespace
367 //===----------------------------------------------------------------------===//
368 // ConstantPackedRules Class
369 //===----------------------------------------------------------------------===//
371 /// DoVectorOp - Given two packed constants and a function pointer, apply the
372 /// function pointer to each element pair, producing a new ConstantPacked
374 static Constant *EvalVectorOp(const ConstantPacked *V1,
375 const ConstantPacked *V2,
376 Constant *(*FP)(Constant*, Constant*)) {
377 std::vector<Constant*> Res;
378 for (unsigned i = 0, e = V1->getNumOperands(); i != e; ++i)
379 Res.push_back(FP(const_cast<Constant*>(V1->getOperand(i)),
380 const_cast<Constant*>(V2->getOperand(i))));
381 return ConstantPacked::get(Res);
384 /// PackedTypeRules provides a concrete base class of ConstRules for
385 /// ConstantPacked operands.
388 struct VISIBILITY_HIDDEN ConstantPackedRules
389 : public TemplateRules<ConstantPacked, ConstantPackedRules> {
391 static Constant *Add(const ConstantPacked *V1, const ConstantPacked *V2) {
392 return EvalVectorOp(V1, V2, ConstantExpr::getAdd);
394 static Constant *Sub(const ConstantPacked *V1, const ConstantPacked *V2) {
395 return EvalVectorOp(V1, V2, ConstantExpr::getSub);
397 static Constant *Mul(const ConstantPacked *V1, const ConstantPacked *V2) {
398 return EvalVectorOp(V1, V2, ConstantExpr::getMul);
400 static Constant *UDiv(const ConstantPacked *V1, const ConstantPacked *V2) {
401 return EvalVectorOp(V1, V2, ConstantExpr::getUDiv);
403 static Constant *SDiv(const ConstantPacked *V1, const ConstantPacked *V2) {
404 return EvalVectorOp(V1, V2, ConstantExpr::getSDiv);
406 static Constant *FDiv(const ConstantPacked *V1, const ConstantPacked *V2) {
407 return EvalVectorOp(V1, V2, ConstantExpr::getFDiv);
409 static Constant *URem(const ConstantPacked *V1, const ConstantPacked *V2) {
410 return EvalVectorOp(V1, V2, ConstantExpr::getURem);
412 static Constant *SRem(const ConstantPacked *V1, const ConstantPacked *V2) {
413 return EvalVectorOp(V1, V2, ConstantExpr::getSRem);
415 static Constant *FRem(const ConstantPacked *V1, const ConstantPacked *V2) {
416 return EvalVectorOp(V1, V2, ConstantExpr::getFRem);
418 static Constant *And(const ConstantPacked *V1, const ConstantPacked *V2) {
419 return EvalVectorOp(V1, V2, ConstantExpr::getAnd);
421 static Constant *Or (const ConstantPacked *V1, const ConstantPacked *V2) {
422 return EvalVectorOp(V1, V2, ConstantExpr::getOr);
424 static Constant *Xor(const ConstantPacked *V1, const ConstantPacked *V2) {
425 return EvalVectorOp(V1, V2, ConstantExpr::getXor);
427 static Constant *LessThan(const ConstantPacked *V1, const ConstantPacked *V2){
430 static Constant *EqualTo(const ConstantPacked *V1, const ConstantPacked *V2) {
431 for (unsigned i = 0, e = V1->getNumOperands(); i != e; ++i) {
433 ConstantExpr::getSetEQ(const_cast<Constant*>(V1->getOperand(i)),
434 const_cast<Constant*>(V2->getOperand(i)));
435 if (ConstantBool *CB = dyn_cast<ConstantBool>(C))
438 // Otherwise, could not decide from any element pairs.
442 } // end anonymous namespace
445 //===----------------------------------------------------------------------===//
446 // GeneralPackedRules Class
447 //===----------------------------------------------------------------------===//
449 /// GeneralPackedRules provides a concrete base class of ConstRules for
450 /// PackedType operands, where both operands are not ConstantPacked. The usual
451 /// cause for this is that one operand is a ConstantAggregateZero.
454 struct VISIBILITY_HIDDEN GeneralPackedRules
455 : public TemplateRules<Constant, GeneralPackedRules> {
457 } // end anonymous namespace
460 //===----------------------------------------------------------------------===//
461 // DirectIntRules Class
462 //===----------------------------------------------------------------------===//
464 // DirectIntRules provides implementations of functions that are valid on
465 // integer types, but not all types in general.
468 template <class BuiltinType, Type **Ty>
469 struct VISIBILITY_HIDDEN DirectIntRules
470 : public TemplateRules<ConstantInt, DirectIntRules<BuiltinType, Ty> > {
472 static Constant *Add(const ConstantInt *V1, const ConstantInt *V2) {
473 BuiltinType R = (BuiltinType)V1->getZExtValue() +
474 (BuiltinType)V2->getZExtValue();
475 return ConstantInt::get(*Ty, R);
478 static Constant *Sub(const ConstantInt *V1, const ConstantInt *V2) {
479 BuiltinType R = (BuiltinType)V1->getZExtValue() -
480 (BuiltinType)V2->getZExtValue();
481 return ConstantInt::get(*Ty, R);
484 static Constant *Mul(const ConstantInt *V1, const ConstantInt *V2) {
485 BuiltinType R = (BuiltinType)V1->getZExtValue() *
486 (BuiltinType)V2->getZExtValue();
487 return ConstantInt::get(*Ty, R);
490 static Constant *LessThan(const ConstantInt *V1, const ConstantInt *V2) {
491 bool R = (BuiltinType)V1->getZExtValue() < (BuiltinType)V2->getZExtValue();
492 return ConstantBool::get(R);
495 static Constant *EqualTo(const ConstantInt *V1, const ConstantInt *V2) {
496 bool R = (BuiltinType)V1->getZExtValue() == (BuiltinType)V2->getZExtValue();
497 return ConstantBool::get(R);
500 static Constant *CastToPointer(const ConstantInt *V,
501 const PointerType *PTy) {
502 if (V->isNullValue()) // Is it a FP or Integral null value?
503 return ConstantPointerNull::get(PTy);
504 return 0; // Can't const prop other types of pointers
507 // Casting operators. ick
508 #define DEF_CAST(TYPE, CLASS, CTYPE) \
509 static Constant *CastTo##TYPE (const ConstantInt *V) { \
510 return CLASS::get(Type::TYPE##Ty, (CTYPE)((BuiltinType)V->getZExtValue()));\
513 DEF_CAST(Bool , ConstantBool, bool)
514 DEF_CAST(SByte , ConstantInt, signed char)
515 DEF_CAST(UByte , ConstantInt, unsigned char)
516 DEF_CAST(Short , ConstantInt, signed short)
517 DEF_CAST(UShort, ConstantInt, unsigned short)
518 DEF_CAST(Int , ConstantInt, signed int)
519 DEF_CAST(UInt , ConstantInt, unsigned int)
520 DEF_CAST(Long , ConstantInt, int64_t)
521 DEF_CAST(ULong , ConstantInt, uint64_t)
522 DEF_CAST(Float , ConstantFP , float)
523 DEF_CAST(Double, ConstantFP , double)
526 static Constant *UDiv(const ConstantInt *V1, const ConstantInt *V2) {
527 if (V2->isNullValue()) // X / 0
529 BuiltinType R = (BuiltinType)(V1->getZExtValue() / V2->getZExtValue());
530 return ConstantInt::get(*Ty, R);
533 static Constant *SDiv(const ConstantInt *V1, const ConstantInt *V2) {
534 if (V2->isNullValue()) // X / 0
536 if (V2->isAllOnesValue() && // MIN_INT / -1
537 (BuiltinType)V1->getSExtValue() == -(BuiltinType)V1->getSExtValue())
539 BuiltinType R = (BuiltinType)(V1->getSExtValue() / V2->getSExtValue());
540 return ConstantInt::get(*Ty, R);
543 static Constant *URem(const ConstantInt *V1,
544 const ConstantInt *V2) {
545 if (V2->isNullValue()) return 0; // X / 0
546 BuiltinType R = (BuiltinType)(V1->getZExtValue() % V2->getZExtValue());
547 return ConstantInt::get(*Ty, R);
550 static Constant *SRem(const ConstantInt *V1,
551 const ConstantInt *V2) {
552 if (V2->isNullValue()) return 0; // X % 0
553 if (V2->isAllOnesValue() && // MIN_INT % -1
554 (BuiltinType)V1->getSExtValue() == -(BuiltinType)V1->getSExtValue())
556 BuiltinType R = (BuiltinType)(V1->getSExtValue() % V2->getSExtValue());
557 return ConstantInt::get(*Ty, R);
560 static Constant *And(const ConstantInt *V1, const ConstantInt *V2) {
562 (BuiltinType)V1->getZExtValue() & (BuiltinType)V2->getZExtValue();
563 return ConstantInt::get(*Ty, R);
565 static Constant *Or(const ConstantInt *V1, const ConstantInt *V2) {
567 (BuiltinType)V1->getZExtValue() | (BuiltinType)V2->getZExtValue();
568 return ConstantInt::get(*Ty, R);
570 static Constant *Xor(const ConstantInt *V1, const ConstantInt *V2) {
572 (BuiltinType)V1->getZExtValue() ^ (BuiltinType)V2->getZExtValue();
573 return ConstantInt::get(*Ty, R);
576 static Constant *Shl(const ConstantInt *V1, const ConstantInt *V2) {
578 (BuiltinType)V1->getZExtValue() << (BuiltinType)V2->getZExtValue();
579 return ConstantInt::get(*Ty, R);
582 static Constant *LShr(const ConstantInt *V1, const ConstantInt *V2) {
583 BuiltinType R = BuiltinType(V1->getZExtValue() >> V2->getZExtValue());
584 return ConstantInt::get(*Ty, R);
587 static Constant *AShr(const ConstantInt *V1, const ConstantInt *V2) {
588 BuiltinType R = BuiltinType(V1->getSExtValue() >> V2->getZExtValue());
589 return ConstantInt::get(*Ty, R);
592 } // end anonymous namespace
595 //===----------------------------------------------------------------------===//
596 // DirectFPRules Class
597 //===----------------------------------------------------------------------===//
599 /// DirectFPRules provides implementations of functions that are valid on
600 /// floating point types, but not all types in general.
603 template <class BuiltinType, Type **Ty>
604 struct VISIBILITY_HIDDEN DirectFPRules
605 : public TemplateRules<ConstantFP, DirectFPRules<BuiltinType, Ty> > {
607 static Constant *Add(const ConstantFP *V1, const ConstantFP *V2) {
608 BuiltinType R = (BuiltinType)V1->getValue() +
609 (BuiltinType)V2->getValue();
610 return ConstantFP::get(*Ty, R);
613 static Constant *Sub(const ConstantFP *V1, const ConstantFP *V2) {
614 BuiltinType R = (BuiltinType)V1->getValue() - (BuiltinType)V2->getValue();
615 return ConstantFP::get(*Ty, R);
618 static Constant *Mul(const ConstantFP *V1, const ConstantFP *V2) {
619 BuiltinType R = (BuiltinType)V1->getValue() * (BuiltinType)V2->getValue();
620 return ConstantFP::get(*Ty, R);
623 static Constant *LessThan(const ConstantFP *V1, const ConstantFP *V2) {
624 bool R = (BuiltinType)V1->getValue() < (BuiltinType)V2->getValue();
625 return ConstantBool::get(R);
628 static Constant *EqualTo(const ConstantFP *V1, const ConstantFP *V2) {
629 bool R = (BuiltinType)V1->getValue() == (BuiltinType)V2->getValue();
630 return ConstantBool::get(R);
633 static Constant *CastToPointer(const ConstantFP *V,
634 const PointerType *PTy) {
635 if (V->isNullValue()) // Is it a FP or Integral null value?
636 return ConstantPointerNull::get(PTy);
637 return 0; // Can't const prop other types of pointers
640 // Casting operators. ick
641 #define DEF_CAST(TYPE, CLASS, CTYPE) \
642 static Constant *CastTo##TYPE (const ConstantFP *V) { \
643 return CLASS::get(Type::TYPE##Ty, (CTYPE)(BuiltinType)V->getValue()); \
646 DEF_CAST(Bool , ConstantBool, bool)
647 DEF_CAST(SByte , ConstantInt, signed char)
648 DEF_CAST(UByte , ConstantInt, unsigned char)
649 DEF_CAST(Short , ConstantInt, signed short)
650 DEF_CAST(UShort, ConstantInt, unsigned short)
651 DEF_CAST(Int , ConstantInt, signed int)
652 DEF_CAST(UInt , ConstantInt, unsigned int)
653 DEF_CAST(Long , ConstantInt, int64_t)
654 DEF_CAST(ULong , ConstantInt, uint64_t)
655 DEF_CAST(Float , ConstantFP , float)
656 DEF_CAST(Double, ConstantFP , double)
659 static Constant *FRem(const ConstantFP *V1, const ConstantFP *V2) {
660 if (V2->isNullValue()) return 0;
661 BuiltinType Result = std::fmod((BuiltinType)V1->getValue(),
662 (BuiltinType)V2->getValue());
663 return ConstantFP::get(*Ty, Result);
665 static Constant *FDiv(const ConstantFP *V1, const ConstantFP *V2) {
666 BuiltinType inf = std::numeric_limits<BuiltinType>::infinity();
667 if (V2->isExactlyValue(0.0)) return ConstantFP::get(*Ty, inf);
668 if (V2->isExactlyValue(-0.0)) return ConstantFP::get(*Ty, -inf);
669 BuiltinType R = (BuiltinType)V1->getValue() / (BuiltinType)V2->getValue();
670 return ConstantFP::get(*Ty, R);
673 } // end anonymous namespace
675 static ManagedStatic<EmptyRules> EmptyR;
676 static ManagedStatic<BoolRules> BoolR;
677 static ManagedStatic<NullPointerRules> NullPointerR;
678 static ManagedStatic<ConstantPackedRules> ConstantPackedR;
679 static ManagedStatic<GeneralPackedRules> GeneralPackedR;
680 static ManagedStatic<DirectIntRules<signed char , &Type::SByteTy> > SByteR;
681 static ManagedStatic<DirectIntRules<unsigned char , &Type::UByteTy> > UByteR;
682 static ManagedStatic<DirectIntRules<signed short , &Type::ShortTy> > ShortR;
683 static ManagedStatic<DirectIntRules<unsigned short, &Type::UShortTy> > UShortR;
684 static ManagedStatic<DirectIntRules<signed int , &Type::IntTy> > IntR;
685 static ManagedStatic<DirectIntRules<unsigned int , &Type::UIntTy> > UIntR;
686 static ManagedStatic<DirectIntRules<int64_t , &Type::LongTy> > LongR;
687 static ManagedStatic<DirectIntRules<uint64_t , &Type::ULongTy> > ULongR;
688 static ManagedStatic<DirectFPRules <float , &Type::FloatTy> > FloatR;
689 static ManagedStatic<DirectFPRules <double , &Type::DoubleTy> > DoubleR;
691 /// ConstRules::get - This method returns the constant rules implementation that
692 /// implements the semantics of the two specified constants.
693 ConstRules &ConstRules::get(const Constant *V1, const Constant *V2) {
694 if (isa<ConstantExpr>(V1) || isa<ConstantExpr>(V2) ||
695 isa<GlobalValue>(V1) || isa<GlobalValue>(V2) ||
696 isa<UndefValue>(V1) || isa<UndefValue>(V2))
699 switch (V1->getType()->getTypeID()) {
700 default: assert(0 && "Unknown value type for constant folding!");
701 case Type::BoolTyID: return *BoolR;
702 case Type::PointerTyID: return *NullPointerR;
703 case Type::SByteTyID: return *SByteR;
704 case Type::UByteTyID: return *UByteR;
705 case Type::ShortTyID: return *ShortR;
706 case Type::UShortTyID: return *UShortR;
707 case Type::IntTyID: return *IntR;
708 case Type::UIntTyID: return *UIntR;
709 case Type::LongTyID: return *LongR;
710 case Type::ULongTyID: return *ULongR;
711 case Type::FloatTyID: return *FloatR;
712 case Type::DoubleTyID: return *DoubleR;
713 case Type::PackedTyID:
714 if (isa<ConstantPacked>(V1) && isa<ConstantPacked>(V2))
715 return *ConstantPackedR;
716 return *GeneralPackedR; // Constant folding rules for ConstantAggregateZero.
721 //===----------------------------------------------------------------------===//
722 // ConstantFold*Instruction Implementations
723 //===----------------------------------------------------------------------===//
725 /// CastConstantPacked - Convert the specified ConstantPacked node to the
726 /// specified packed type. At this point, we know that the elements of the
727 /// input packed constant are all simple integer or FP values.
728 static Constant *CastConstantPacked(ConstantPacked *CP,
729 const PackedType *DstTy) {
730 unsigned SrcNumElts = CP->getType()->getNumElements();
731 unsigned DstNumElts = DstTy->getNumElements();
732 const Type *SrcEltTy = CP->getType()->getElementType();
733 const Type *DstEltTy = DstTy->getElementType();
735 // If both vectors have the same number of elements (thus, the elements
736 // are the same size), perform the conversion now.
737 if (SrcNumElts == DstNumElts) {
738 std::vector<Constant*> Result;
740 // If the src and dest elements are both integers, or both floats, we can
741 // just BitCast each element because the elements are the same size.
742 if ((SrcEltTy->isIntegral() && DstEltTy->isIntegral()) ||
743 (SrcEltTy->isFloatingPoint() && DstEltTy->isFloatingPoint())) {
744 for (unsigned i = 0; i != SrcNumElts; ++i)
746 ConstantExpr::getCast(Instruction::BitCast, CP->getOperand(1),
748 return ConstantPacked::get(Result);
751 // If this is an int-to-fp cast ..
752 if (SrcEltTy->isIntegral()) {
753 // Ensure that it is int-to-fp cast
754 assert(DstEltTy->isFloatingPoint());
755 if (DstEltTy->getTypeID() == Type::DoubleTyID) {
756 for (unsigned i = 0; i != SrcNumElts; ++i) {
758 BitsToDouble(cast<ConstantInt>(CP->getOperand(i))->getZExtValue());
759 Result.push_back(ConstantFP::get(Type::DoubleTy, V));
761 return ConstantPacked::get(Result);
763 assert(DstEltTy == Type::FloatTy && "Unknown fp type!");
764 for (unsigned i = 0; i != SrcNumElts; ++i) {
766 BitsToFloat(cast<ConstantInt>(CP->getOperand(i))->getZExtValue());
767 Result.push_back(ConstantFP::get(Type::FloatTy, V));
769 return ConstantPacked::get(Result);
772 // Otherwise, this is an fp-to-int cast.
773 assert(SrcEltTy->isFloatingPoint() && DstEltTy->isIntegral());
775 if (SrcEltTy->getTypeID() == Type::DoubleTyID) {
776 for (unsigned i = 0; i != SrcNumElts; ++i) {
778 DoubleToBits(cast<ConstantFP>(CP->getOperand(i))->getValue());
779 Constant *C = ConstantInt::get(Type::ULongTy, V);
780 Result.push_back(ConstantExpr::getCast(C, DstEltTy));
782 return ConstantPacked::get(Result);
785 assert(SrcEltTy->getTypeID() == Type::FloatTyID);
786 for (unsigned i = 0; i != SrcNumElts; ++i) {
787 uint32_t V = FloatToBits(cast<ConstantFP>(CP->getOperand(i))->getValue());
788 Constant *C = ConstantInt::get(Type::UIntTy, V);
789 Result.push_back(ConstantExpr::getCast(C, DstEltTy));
791 return ConstantPacked::get(Result);
794 // Otherwise, this is a cast that changes element count and size. Handle
795 // casts which shrink the elements here.
797 // FIXME: We need to know endianness to do this!
802 /// This function determines which opcode to use to fold two constant cast
803 /// expressions together. It uses CastInst::isEliminableCastPair to determine
804 /// the opcode. Consequently its just a wrapper around that function.
805 /// @Determine if it is valid to fold a cast of a cast
807 foldConstantCastPair(
808 unsigned opc, ///< opcode of the second cast constant expression
809 const ConstantExpr*Op, ///< the first cast constant expression
810 const Type *DstTy ///< desintation type of the first cast
812 assert(Op && Op->isCast() && "Can't fold cast of cast without a cast!");
813 assert(DstTy && DstTy->isFirstClassType() && "Invalid cast destination type");
814 assert(CastInst::isCast(opc) && "Invalid cast opcode");
816 // The the types and opcodes for the two Cast constant expressions
817 const Type *SrcTy = Op->getOperand(0)->getType();
818 const Type *MidTy = Op->getType();
819 Instruction::CastOps firstOp = Instruction::CastOps(Op->getOpcode());
820 Instruction::CastOps secondOp = Instruction::CastOps(opc);
822 // Let CastInst::isEliminableCastPair do the heavy lifting.
823 return CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy, DstTy,
827 Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
828 const Type *DestTy) {
829 const Type *SrcTy = V->getType();
831 // Handle some simple cases
833 return (Constant*)V; // no-op cast
835 if (isa<UndefValue>(V))
836 return UndefValue::get(DestTy);
838 // If the cast operand is a constant expression, there's a few things we can
839 // do to try to simplify it.
840 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
842 // Try hard to fold cast of cast because they are almost always
844 if (unsigned newOpc = foldConstantCastPair(opc, CE, DestTy))
845 return ConstantExpr::getCast(newOpc, CE->getOperand(0), DestTy);
846 } else if (CE->getOpcode() == Instruction::GetElementPtr) {
847 // If all of the indexes in the GEP are null values, there is no pointer
848 // adjustment going on. We might as well cast the source pointer.
849 bool isAllNull = true;
850 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
851 if (!CE->getOperand(i)->isNullValue()) {
856 return ConstantExpr::getCast(CE->getOperand(0), DestTy);
860 // We actually have to do a cast now, but first, we might need to fix up
861 // the value of the operand.
863 case Instruction::FPTrunc:
864 case Instruction::Trunc:
865 case Instruction::FPExt:
866 break; // floating point input & output, no fixup needed
867 case Instruction::FPToUI: {
868 ConstRules &Rules = ConstRules::get(V, V);
869 V = Rules.castToULong(V); // make sure we get an unsigned value first
872 case Instruction::FPToSI: {
873 ConstRules &Rules = ConstRules::get(V, V);
874 V = Rules.castToLong(V); // make sure we get a signed value first
877 case Instruction::IntToPtr: //always treated as unsigned
878 case Instruction::UIToFP:
879 case Instruction::ZExt:
880 // A ZExt always produces an unsigned value so we need to cast the value
881 // now before we try to cast it to the destination type
882 if (isa<ConstantInt>(V))
883 V = ConstantInt::get(SrcTy->getUnsignedVersion(),
884 cast<ConstantIntegral>(V)->getZExtValue());
886 case Instruction::SIToFP:
887 case Instruction::SExt:
888 // A SExt always produces a signed value so we need to cast the value
889 // now before we try to cast it to the destiniation type.
890 if (isa<ConstantInt>(V))
891 V = ConstantInt::get(SrcTy->getSignedVersion(),
892 cast<ConstantIntegral>(V)->getSExtValue());
895 case Instruction::PtrToInt:
897 case Instruction::BitCast:
898 // Check to see if we are casting a pointer to an aggregate to a pointer to
899 // the first element. If so, return the appropriate GEP instruction.
900 if (const PointerType *PTy = dyn_cast<PointerType>(V->getType()))
901 if (const PointerType *DPTy = dyn_cast<PointerType>(DestTy)) {
902 std::vector<Value*> IdxList;
903 IdxList.push_back(Constant::getNullValue(Type::IntTy));
904 const Type *ElTy = PTy->getElementType();
905 while (ElTy != DPTy->getElementType()) {
906 if (const StructType *STy = dyn_cast<StructType>(ElTy)) {
907 if (STy->getNumElements() == 0) break;
908 ElTy = STy->getElementType(0);
909 IdxList.push_back(Constant::getNullValue(Type::UIntTy));
910 } else if (const SequentialType *STy =
911 dyn_cast<SequentialType>(ElTy)) {
912 if (isa<PointerType>(ElTy)) break; // Can't index into pointers!
913 ElTy = STy->getElementType();
914 IdxList.push_back(IdxList[0]);
920 if (ElTy == DPTy->getElementType())
921 return ConstantExpr::getGetElementPtr(
922 const_cast<Constant*>(V),IdxList);
925 // Handle casts from one packed constant to another. We know that the src
926 // and dest type have the same size (otherwise its an illegal cast).
927 if (const PackedType *DestPTy = dyn_cast<PackedType>(DestTy)) {
928 if (const PackedType *SrcTy = dyn_cast<PackedType>(V->getType())) {
929 assert(DestPTy->getBitWidth() == SrcTy->getBitWidth() &&
930 "Not cast between same sized vectors!");
931 // First, check for null and undef
932 if (isa<ConstantAggregateZero>(V))
933 return Constant::getNullValue(DestTy);
934 if (isa<UndefValue>(V))
935 return UndefValue::get(DestTy);
937 if (const ConstantPacked *CP = dyn_cast<ConstantPacked>(V)) {
938 // This is a cast from a ConstantPacked of one type to a
939 // ConstantPacked of another type. Check to see if all elements of
940 // the input are simple.
941 bool AllSimpleConstants = true;
942 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) {
943 if (!isa<ConstantInt>(CP->getOperand(i)) &&
944 !isa<ConstantFP>(CP->getOperand(i))) {
945 AllSimpleConstants = false;
950 // If all of the elements are simple constants, we can fold this.
951 if (AllSimpleConstants)
952 return CastConstantPacked(const_cast<ConstantPacked*>(CP), DestPTy);
957 // Handle sign conversion for integer no-op casts. We need to cast the
958 // value to the correct signedness before we try to cast it to the
959 // destination type. Be careful to do this only for integer types.
960 if (isa<ConstantIntegral>(V) && SrcTy->isInteger()) {
961 if (SrcTy->isSigned())
962 V = ConstantInt::get(SrcTy->getUnsignedVersion(),
963 cast<ConstantIntegral>(V)->getZExtValue());
965 V = ConstantInt::get(SrcTy->getSignedVersion(),
966 cast<ConstantIntegral>(V)->getSExtValue());
970 assert(!"Invalid CE CastInst opcode");
974 // Okay, no more folding possible, time to cast
975 ConstRules &Rules = ConstRules::get(V, V);
976 switch (DestTy->getTypeID()) {
977 case Type::BoolTyID: return Rules.castToBool(V);
978 case Type::UByteTyID: return Rules.castToUByte(V);
979 case Type::SByteTyID: return Rules.castToSByte(V);
980 case Type::UShortTyID: return Rules.castToUShort(V);
981 case Type::ShortTyID: return Rules.castToShort(V);
982 case Type::UIntTyID: return Rules.castToUInt(V);
983 case Type::IntTyID: return Rules.castToInt(V);
984 case Type::ULongTyID: return Rules.castToULong(V);
985 case Type::LongTyID: return Rules.castToLong(V);
986 case Type::FloatTyID: return Rules.castToFloat(V);
987 case Type::DoubleTyID: return Rules.castToDouble(V);
988 case Type::PointerTyID:
989 return Rules.castToPointer(V, cast<PointerType>(DestTy));
990 // what about packed ?
995 Constant *llvm::ConstantFoldSelectInstruction(const Constant *Cond,
997 const Constant *V2) {
998 if (const ConstantBool *CB = dyn_cast<ConstantBool>(Cond))
999 return const_cast<Constant*>(CB->getValue() ? V1 : V2);
1001 if (isa<UndefValue>(V1)) return const_cast<Constant*>(V2);
1002 if (isa<UndefValue>(V2)) return const_cast<Constant*>(V1);
1003 if (isa<UndefValue>(Cond)) return const_cast<Constant*>(V1);
1004 if (V1 == V2) return const_cast<Constant*>(V1);
1008 Constant *llvm::ConstantFoldExtractElementInstruction(const Constant *Val,
1009 const Constant *Idx) {
1010 if (isa<UndefValue>(Val)) // ee(undef, x) -> undef
1011 return UndefValue::get(cast<PackedType>(Val->getType())->getElementType());
1012 if (Val->isNullValue()) // ee(zero, x) -> zero
1013 return Constant::getNullValue(
1014 cast<PackedType>(Val->getType())->getElementType());
1016 if (const ConstantPacked *CVal = dyn_cast<ConstantPacked>(Val)) {
1017 if (const ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx)) {
1018 return const_cast<Constant*>(CVal->getOperand(CIdx->getZExtValue()));
1019 } else if (isa<UndefValue>(Idx)) {
1020 // ee({w,x,y,z}, undef) -> w (an arbitrary value).
1021 return const_cast<Constant*>(CVal->getOperand(0));
1027 Constant *llvm::ConstantFoldInsertElementInstruction(const Constant *Val,
1028 const Constant *Elt,
1029 const Constant *Idx) {
1030 const ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx);
1031 if (!CIdx) return 0;
1032 uint64_t idxVal = CIdx->getZExtValue();
1033 if (isa<UndefValue>(Val)) {
1034 // Insertion of scalar constant into packed undef
1035 // Optimize away insertion of undef
1036 if (isa<UndefValue>(Elt))
1037 return const_cast<Constant*>(Val);
1038 // Otherwise break the aggregate undef into multiple undefs and do
1041 cast<PackedType>(Val->getType())->getNumElements();
1042 std::vector<Constant*> Ops;
1043 Ops.reserve(numOps);
1044 for (unsigned i = 0; i < numOps; ++i) {
1045 const Constant *Op =
1046 (i == idxVal) ? Elt : UndefValue::get(Elt->getType());
1047 Ops.push_back(const_cast<Constant*>(Op));
1049 return ConstantPacked::get(Ops);
1051 if (isa<ConstantAggregateZero>(Val)) {
1052 // Insertion of scalar constant into packed aggregate zero
1053 // Optimize away insertion of zero
1054 if (Elt->isNullValue())
1055 return const_cast<Constant*>(Val);
1056 // Otherwise break the aggregate zero into multiple zeros and do
1059 cast<PackedType>(Val->getType())->getNumElements();
1060 std::vector<Constant*> Ops;
1061 Ops.reserve(numOps);
1062 for (unsigned i = 0; i < numOps; ++i) {
1063 const Constant *Op =
1064 (i == idxVal) ? Elt : Constant::getNullValue(Elt->getType());
1065 Ops.push_back(const_cast<Constant*>(Op));
1067 return ConstantPacked::get(Ops);
1069 if (const ConstantPacked *CVal = dyn_cast<ConstantPacked>(Val)) {
1070 // Insertion of scalar constant into packed constant
1071 std::vector<Constant*> Ops;
1072 Ops.reserve(CVal->getNumOperands());
1073 for (unsigned i = 0; i < CVal->getNumOperands(); ++i) {
1074 const Constant *Op =
1075 (i == idxVal) ? Elt : cast<Constant>(CVal->getOperand(i));
1076 Ops.push_back(const_cast<Constant*>(Op));
1078 return ConstantPacked::get(Ops);
1083 Constant *llvm::ConstantFoldShuffleVectorInstruction(const Constant *V1,
1085 const Constant *Mask) {
1091 /// isZeroSizedType - This type is zero sized if its an array or structure of
1092 /// zero sized types. The only leaf zero sized type is an empty structure.
1093 static bool isMaybeZeroSizedType(const Type *Ty) {
1094 if (isa<OpaqueType>(Ty)) return true; // Can't say.
1095 if (const StructType *STy = dyn_cast<StructType>(Ty)) {
1097 // If all of elements have zero size, this does too.
1098 for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
1099 if (!isMaybeZeroSizedType(STy->getElementType(i))) return false;
1102 } else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
1103 return isMaybeZeroSizedType(ATy->getElementType());
1108 /// IdxCompare - Compare the two constants as though they were getelementptr
1109 /// indices. This allows coersion of the types to be the same thing.
1111 /// If the two constants are the "same" (after coersion), return 0. If the
1112 /// first is less than the second, return -1, if the second is less than the
1113 /// first, return 1. If the constants are not integral, return -2.
1115 static int IdxCompare(Constant *C1, Constant *C2, const Type *ElTy) {
1116 if (C1 == C2) return 0;
1118 // Ok, we found a different index. Are either of the operands ConstantExprs?
1119 // If so, we can't do anything with them.
1120 if (!isa<ConstantInt>(C1) || !isa<ConstantInt>(C2))
1121 return -2; // don't know!
1123 // Ok, we have two differing integer indices. Sign extend them to be the same
1124 // type. Long is always big enough, so we use it.
1125 if (C1->getType() != Type::LongTy && C1->getType() != Type::ULongTy)
1126 C1 = ConstantExpr::getSignExtend(C1, Type::LongTy);
1128 C1 = ConstantExpr::getBitCast(C1, Type::LongTy);
1129 if (C2->getType() != Type::LongTy && C1->getType() != Type::ULongTy)
1130 C2 = ConstantExpr::getSignExtend(C2, Type::LongTy);
1132 C2 = ConstantExpr::getBitCast(C2, Type::LongTy);
1134 if (C1 == C2) return 0; // Are they just differing types?
1136 // If the type being indexed over is really just a zero sized type, there is
1137 // no pointer difference being made here.
1138 if (isMaybeZeroSizedType(ElTy))
1139 return -2; // dunno.
1141 // If they are really different, now that they are the same type, then we
1142 // found a difference!
1143 if (cast<ConstantInt>(C1)->getSExtValue() <
1144 cast<ConstantInt>(C2)->getSExtValue())
1150 /// evaluateRelation - This function determines if there is anything we can
1151 /// decide about the two constants provided. This doesn't need to handle simple
1152 /// things like integer comparisons, but should instead handle ConstantExprs
1153 /// and GlobalValuess. If we can determine that the two constants have a
1154 /// particular relation to each other, we should return the corresponding SetCC
1155 /// code, otherwise return Instruction::BinaryOpsEnd.
1157 /// To simplify this code we canonicalize the relation so that the first
1158 /// operand is always the most "complex" of the two. We consider simple
1159 /// constants (like ConstantInt) to be the simplest, followed by
1160 /// GlobalValues, followed by ConstantExpr's (the most complex).
1162 static Instruction::BinaryOps evaluateRelation(Constant *V1, Constant *V2) {
1163 assert(V1->getType() == V2->getType() &&
1164 "Cannot compare different types of values!");
1165 if (V1 == V2) return Instruction::SetEQ;
1167 if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1)) {
1168 if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2)) {
1169 // We distilled this down to a simple case, use the standard constant
1171 ConstantBool *R = dyn_cast<ConstantBool>(ConstantExpr::getSetEQ(V1, V2));
1172 if (R && R->getValue()) return Instruction::SetEQ;
1173 R = dyn_cast<ConstantBool>(ConstantExpr::getSetLT(V1, V2));
1174 if (R && R->getValue()) return Instruction::SetLT;
1175 R = dyn_cast<ConstantBool>(ConstantExpr::getSetGT(V1, V2));
1176 if (R && R->getValue()) return Instruction::SetGT;
1178 // If we couldn't figure it out, bail.
1179 return Instruction::BinaryOpsEnd;
1182 // If the first operand is simple, swap operands.
1183 Instruction::BinaryOps SwappedRelation = evaluateRelation(V2, V1);
1184 if (SwappedRelation != Instruction::BinaryOpsEnd)
1185 return SetCondInst::getSwappedCondition(SwappedRelation);
1187 } else if (const GlobalValue *CPR1 = dyn_cast<GlobalValue>(V1)) {
1188 if (isa<ConstantExpr>(V2)) { // Swap as necessary.
1189 Instruction::BinaryOps SwappedRelation = evaluateRelation(V2, V1);
1190 if (SwappedRelation != Instruction::BinaryOpsEnd)
1191 return SetCondInst::getSwappedCondition(SwappedRelation);
1193 return Instruction::BinaryOpsEnd;
1196 // Now we know that the RHS is a GlobalValue or simple constant,
1197 // which (since the types must match) means that it's a ConstantPointerNull.
1198 if (const GlobalValue *CPR2 = dyn_cast<GlobalValue>(V2)) {
1199 assert(CPR1 != CPR2 &&
1200 "GVs for the same value exist at different addresses??");
1201 // FIXME: If both globals are external weak, they might both be null!
1202 return Instruction::SetNE;
1204 assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!");
1205 // Global can never be null. FIXME: if we implement external weak
1206 // linkage, this is not necessarily true!
1207 return Instruction::SetNE;
1211 // Ok, the LHS is known to be a constantexpr. The RHS can be any of a
1212 // constantexpr, a CPR, or a simple constant.
1213 ConstantExpr *CE1 = cast<ConstantExpr>(V1);
1214 Constant *CE1Op0 = CE1->getOperand(0);
1216 switch (CE1->getOpcode()) {
1217 case Instruction::Trunc:
1218 case Instruction::FPTrunc:
1219 case Instruction::FPExt:
1220 case Instruction::FPToUI:
1221 case Instruction::FPToSI:
1222 break; // We don't do anything with floating point.
1223 case Instruction::ZExt:
1224 case Instruction::SExt:
1225 case Instruction::UIToFP:
1226 case Instruction::SIToFP:
1227 case Instruction::PtrToInt:
1228 case Instruction::IntToPtr:
1229 case Instruction::BitCast:
1230 // If the cast is not actually changing bits, and the second operand is a
1231 // null pointer, do the comparison with the pre-casted value.
1232 if (V2->isNullValue() &&
1233 (isa<PointerType>(CE1->getType()) || CE1->getType()->isIntegral()))
1234 return evaluateRelation(CE1Op0,
1235 Constant::getNullValue(CE1Op0->getType()));
1237 // If the dest type is a pointer type, and the RHS is a constantexpr cast
1238 // from the same type as the src of the LHS, evaluate the inputs. This is
1239 // important for things like "seteq (cast 4 to int*), (cast 5 to int*)",
1240 // which happens a lot in compilers with tagged integers.
1241 if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(V2))
1242 if (isa<PointerType>(CE1->getType()) && CE2->isCast() &&
1243 CE1->getOperand(0)->getType() == CE2->getOperand(0)->getType() &&
1244 CE1->getOperand(0)->getType()->isIntegral()) {
1245 return evaluateRelation(CE1->getOperand(0), CE2->getOperand(0));
1249 case Instruction::GetElementPtr:
1250 // Ok, since this is a getelementptr, we know that the constant has a
1251 // pointer type. Check the various cases.
1252 if (isa<ConstantPointerNull>(V2)) {
1253 // If we are comparing a GEP to a null pointer, check to see if the base
1254 // of the GEP equals the null pointer.
1255 if (isa<GlobalValue>(CE1Op0)) {
1256 // FIXME: this is not true when we have external weak references!
1257 // No offset can go from a global to a null pointer.
1258 return Instruction::SetGT;
1259 } else if (isa<ConstantPointerNull>(CE1Op0)) {
1260 // If we are indexing from a null pointer, check to see if we have any
1261 // non-zero indices.
1262 for (unsigned i = 1, e = CE1->getNumOperands(); i != e; ++i)
1263 if (!CE1->getOperand(i)->isNullValue())
1264 // Offsetting from null, must not be equal.
1265 return Instruction::SetGT;
1266 // Only zero indexes from null, must still be zero.
1267 return Instruction::SetEQ;
1269 // Otherwise, we can't really say if the first operand is null or not.
1270 } else if (const GlobalValue *CPR2 = dyn_cast<GlobalValue>(V2)) {
1271 if (isa<ConstantPointerNull>(CE1Op0)) {
1272 // FIXME: This is not true with external weak references.
1273 return Instruction::SetLT;
1274 } else if (const GlobalValue *CPR1 = dyn_cast<GlobalValue>(CE1Op0)) {
1276 // If this is a getelementptr of the same global, then it must be
1277 // different. Because the types must match, the getelementptr could
1278 // only have at most one index, and because we fold getelementptr's
1279 // with a single zero index, it must be nonzero.
1280 assert(CE1->getNumOperands() == 2 &&
1281 !CE1->getOperand(1)->isNullValue() &&
1282 "Suprising getelementptr!");
1283 return Instruction::SetGT;
1285 // If they are different globals, we don't know what the value is,
1286 // but they can't be equal.
1287 return Instruction::SetNE;
1291 const ConstantExpr *CE2 = cast<ConstantExpr>(V2);
1292 const Constant *CE2Op0 = CE2->getOperand(0);
1294 // There are MANY other foldings that we could perform here. They will
1295 // probably be added on demand, as they seem needed.
1296 switch (CE2->getOpcode()) {
1298 case Instruction::GetElementPtr:
1299 // By far the most common case to handle is when the base pointers are
1300 // obviously to the same or different globals.
1301 if (isa<GlobalValue>(CE1Op0) && isa<GlobalValue>(CE2Op0)) {
1302 if (CE1Op0 != CE2Op0) // Don't know relative ordering, but not equal
1303 return Instruction::SetNE;
1304 // Ok, we know that both getelementptr instructions are based on the
1305 // same global. From this, we can precisely determine the relative
1306 // ordering of the resultant pointers.
1309 // Compare all of the operands the GEP's have in common.
1310 gep_type_iterator GTI = gep_type_begin(CE1);
1311 for (;i != CE1->getNumOperands() && i != CE2->getNumOperands();
1313 switch (IdxCompare(CE1->getOperand(i), CE2->getOperand(i),
1314 GTI.getIndexedType())) {
1315 case -1: return Instruction::SetLT;
1316 case 1: return Instruction::SetGT;
1317 case -2: return Instruction::BinaryOpsEnd;
1320 // Ok, we ran out of things they have in common. If any leftovers
1321 // are non-zero then we have a difference, otherwise we are equal.
1322 for (; i < CE1->getNumOperands(); ++i)
1323 if (!CE1->getOperand(i)->isNullValue())
1324 if (isa<ConstantIntegral>(CE1->getOperand(i)))
1325 return Instruction::SetGT;
1327 return Instruction::BinaryOpsEnd; // Might be equal.
1329 for (; i < CE2->getNumOperands(); ++i)
1330 if (!CE2->getOperand(i)->isNullValue())
1331 if (isa<ConstantIntegral>(CE2->getOperand(i)))
1332 return Instruction::SetLT;
1334 return Instruction::BinaryOpsEnd; // Might be equal.
1335 return Instruction::SetEQ;
1345 return Instruction::BinaryOpsEnd;
1348 Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
1350 const Constant *V2) {
1354 case Instruction::Add: C = ConstRules::get(V1, V2).add(V1, V2); break;
1355 case Instruction::Sub: C = ConstRules::get(V1, V2).sub(V1, V2); break;
1356 case Instruction::Mul: C = ConstRules::get(V1, V2).mul(V1, V2); break;
1357 case Instruction::UDiv: C = ConstRules::get(V1, V2).udiv(V1, V2); break;
1358 case Instruction::SDiv: C = ConstRules::get(V1, V2).sdiv(V1, V2); break;
1359 case Instruction::FDiv: C = ConstRules::get(V1, V2).fdiv(V1, V2); break;
1360 case Instruction::URem: C = ConstRules::get(V1, V2).urem(V1, V2); break;
1361 case Instruction::SRem: C = ConstRules::get(V1, V2).srem(V1, V2); break;
1362 case Instruction::FRem: C = ConstRules::get(V1, V2).frem(V1, V2); break;
1363 case Instruction::And: C = ConstRules::get(V1, V2).op_and(V1, V2); break;
1364 case Instruction::Or: C = ConstRules::get(V1, V2).op_or (V1, V2); break;
1365 case Instruction::Xor: C = ConstRules::get(V1, V2).op_xor(V1, V2); break;
1366 case Instruction::Shl: C = ConstRules::get(V1, V2).shl(V1, V2); break;
1367 case Instruction::LShr: C = ConstRules::get(V1, V2).lshr(V1, V2); break;
1368 case Instruction::AShr: C = ConstRules::get(V1, V2).ashr(V1, V2); break;
1369 case Instruction::SetEQ:
1370 // SetEQ(null,GV) -> false
1371 if (V1->isNullValue()) {
1372 if (const GlobalValue *GV = dyn_cast<GlobalValue>(V2))
1373 if (!GV->hasExternalWeakLinkage())
1374 return ConstantBool::getFalse();
1375 // SetEQ(GV,null) -> false
1376 } else if (V2->isNullValue()) {
1377 if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1))
1378 if (!GV->hasExternalWeakLinkage())
1379 return ConstantBool::getFalse();
1381 C = ConstRules::get(V1, V2).equalto(V1, V2);
1383 case Instruction::SetLT: C = ConstRules::get(V1, V2).lessthan(V1, V2);break;
1384 case Instruction::SetGT: C = ConstRules::get(V1, V2).lessthan(V2, V1);break;
1385 case Instruction::SetNE:
1386 // SetNE(null,GV) -> true
1387 if (V1->isNullValue()) {
1388 if (const GlobalValue *GV = dyn_cast<GlobalValue>(V2))
1389 if (!GV->hasExternalWeakLinkage())
1390 return ConstantBool::getTrue();
1391 // SetNE(GV,null) -> true
1392 } else if (V2->isNullValue()) {
1393 if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1))
1394 if (!GV->hasExternalWeakLinkage())
1395 return ConstantBool::getTrue();
1397 // V1 != V2 === !(V1 == V2)
1398 C = ConstRules::get(V1, V2).equalto(V1, V2);
1399 if (C) return ConstantExpr::getNot(C);
1401 case Instruction::SetLE: // V1 <= V2 === !(V2 < V1)
1402 C = ConstRules::get(V1, V2).lessthan(V2, V1);
1403 if (C) return ConstantExpr::getNot(C);
1405 case Instruction::SetGE: // V1 >= V2 === !(V1 < V2)
1406 C = ConstRules::get(V1, V2).lessthan(V1, V2);
1407 if (C) return ConstantExpr::getNot(C);
1411 // If we successfully folded the expression, return it now.
1414 if (SetCondInst::isComparison(Opcode)) {
1415 if (isa<UndefValue>(V1) || isa<UndefValue>(V2))
1416 return UndefValue::get(Type::BoolTy);
1417 switch (evaluateRelation(const_cast<Constant*>(V1),
1418 const_cast<Constant*>(V2))) {
1419 default: assert(0 && "Unknown relational!");
1420 case Instruction::BinaryOpsEnd:
1421 break; // Couldn't determine anything about these constants.
1422 case Instruction::SetEQ: // We know the constants are equal!
1423 // If we know the constants are equal, we can decide the result of this
1424 // computation precisely.
1425 return ConstantBool::get(Opcode == Instruction::SetEQ ||
1426 Opcode == Instruction::SetLE ||
1427 Opcode == Instruction::SetGE);
1428 case Instruction::SetLT:
1429 // If we know that V1 < V2, we can decide the result of this computation
1431 return ConstantBool::get(Opcode == Instruction::SetLT ||
1432 Opcode == Instruction::SetNE ||
1433 Opcode == Instruction::SetLE);
1434 case Instruction::SetGT:
1435 // If we know that V1 > V2, we can decide the result of this computation
1437 return ConstantBool::get(Opcode == Instruction::SetGT ||
1438 Opcode == Instruction::SetNE ||
1439 Opcode == Instruction::SetGE);
1440 case Instruction::SetLE:
1441 // If we know that V1 <= V2, we can only partially decide this relation.
1442 if (Opcode == Instruction::SetGT) return ConstantBool::getFalse();
1443 if (Opcode == Instruction::SetLT) return ConstantBool::getTrue();
1446 case Instruction::SetGE:
1447 // If we know that V1 >= V2, we can only partially decide this relation.
1448 if (Opcode == Instruction::SetLT) return ConstantBool::getFalse();
1449 if (Opcode == Instruction::SetGT) return ConstantBool::getTrue();
1452 case Instruction::SetNE:
1453 // If we know that V1 != V2, we can only partially decide this relation.
1454 if (Opcode == Instruction::SetEQ) return ConstantBool::getFalse();
1455 if (Opcode == Instruction::SetNE) return ConstantBool::getTrue();
1460 if (isa<UndefValue>(V1) || isa<UndefValue>(V2)) {
1462 case Instruction::Add:
1463 case Instruction::Sub:
1464 case Instruction::Xor:
1465 return UndefValue::get(V1->getType());
1467 case Instruction::Mul:
1468 case Instruction::And:
1469 return Constant::getNullValue(V1->getType());
1470 case Instruction::UDiv:
1471 case Instruction::SDiv:
1472 case Instruction::FDiv:
1473 case Instruction::URem:
1474 case Instruction::SRem:
1475 case Instruction::FRem:
1476 if (!isa<UndefValue>(V2)) // undef / X -> 0
1477 return Constant::getNullValue(V1->getType());
1478 return const_cast<Constant*>(V2); // X / undef -> undef
1479 case Instruction::Or: // X | undef -> -1
1480 return ConstantInt::getAllOnesValue(V1->getType());
1481 case Instruction::LShr:
1482 if (isa<UndefValue>(V2) && isa<UndefValue>(V1))
1483 return const_cast<Constant*>(V1); // undef lshr undef -> undef
1484 return Constant::getNullValue(V1->getType()); // X lshr undef -> 0
1485 // undef lshr X -> 0
1486 case Instruction::AShr:
1487 if (!isa<UndefValue>(V2))
1488 return const_cast<Constant*>(V1); // undef ashr X --> undef
1489 else if (isa<UndefValue>(V1))
1490 return const_cast<Constant*>(V1); // undef ashr undef -> undef
1492 return const_cast<Constant*>(V1); // X ashr undef --> X
1493 case Instruction::Shl:
1494 // undef << X -> 0 or X << undef -> 0
1495 return Constant::getNullValue(V1->getType());
1499 if (const ConstantExpr *CE1 = dyn_cast<ConstantExpr>(V1)) {
1500 if (isa<ConstantExpr>(V2)) {
1501 // There are many possible foldings we could do here. We should probably
1502 // at least fold add of a pointer with an integer into the appropriate
1503 // getelementptr. This will improve alias analysis a bit.
1505 // Just implement a couple of simple identities.
1507 case Instruction::Add:
1508 if (V2->isNullValue()) return const_cast<Constant*>(V1); // X + 0 == X
1510 case Instruction::Sub:
1511 if (V2->isNullValue()) return const_cast<Constant*>(V1); // X - 0 == X
1513 case Instruction::Mul:
1514 if (V2->isNullValue()) return const_cast<Constant*>(V2); // X * 0 == 0
1515 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V2))
1516 if (CI->getZExtValue() == 1)
1517 return const_cast<Constant*>(V1); // X * 1 == X
1519 case Instruction::UDiv:
1520 case Instruction::SDiv:
1521 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V2))
1522 if (CI->getZExtValue() == 1)
1523 return const_cast<Constant*>(V1); // X / 1 == X
1525 case Instruction::URem:
1526 case Instruction::SRem:
1527 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V2))
1528 if (CI->getZExtValue() == 1)
1529 return Constant::getNullValue(CI->getType()); // X % 1 == 0
1531 case Instruction::And:
1532 if (cast<ConstantIntegral>(V2)->isAllOnesValue())
1533 return const_cast<Constant*>(V1); // X & -1 == X
1534 if (V2->isNullValue()) return const_cast<Constant*>(V2); // X & 0 == 0
1535 if (CE1->isCast() && isa<GlobalValue>(CE1->getOperand(0))) {
1536 GlobalValue *CPR = cast<GlobalValue>(CE1->getOperand(0));
1538 // Functions are at least 4-byte aligned. If and'ing the address of a
1539 // function with a constant < 4, fold it to zero.
1540 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V2))
1541 if (CI->getZExtValue() < 4 && isa<Function>(CPR))
1542 return Constant::getNullValue(CI->getType());
1545 case Instruction::Or:
1546 if (V2->isNullValue()) return const_cast<Constant*>(V1); // X | 0 == X
1547 if (cast<ConstantIntegral>(V2)->isAllOnesValue())
1548 return const_cast<Constant*>(V2); // X | -1 == -1
1550 case Instruction::Xor:
1551 if (V2->isNullValue()) return const_cast<Constant*>(V1); // X ^ 0 == X
1556 } else if (isa<ConstantExpr>(V2)) {
1557 // If V2 is a constant expr and V1 isn't, flop them around and fold the
1558 // other way if possible.
1560 case Instruction::Add:
1561 case Instruction::Mul:
1562 case Instruction::And:
1563 case Instruction::Or:
1564 case Instruction::Xor:
1565 case Instruction::SetEQ:
1566 case Instruction::SetNE:
1567 // No change of opcode required.
1568 return ConstantFoldBinaryInstruction(Opcode, V2, V1);
1570 case Instruction::SetLT:
1571 case Instruction::SetGT:
1572 case Instruction::SetLE:
1573 case Instruction::SetGE:
1574 // Change the opcode as necessary to swap the operands.
1575 Opcode = SetCondInst::getSwappedCondition((Instruction::BinaryOps)Opcode);
1576 return ConstantFoldBinaryInstruction(Opcode, V2, V1);
1578 case Instruction::Shl:
1579 case Instruction::LShr:
1580 case Instruction::AShr:
1581 case Instruction::Sub:
1582 case Instruction::SDiv:
1583 case Instruction::UDiv:
1584 case Instruction::FDiv:
1585 case Instruction::URem:
1586 case Instruction::SRem:
1587 case Instruction::FRem:
1588 default: // These instructions cannot be flopped around.
1595 Constant *llvm::ConstantFoldGetElementPtr(const Constant *C,
1596 const std::vector<Value*> &IdxList) {
1597 if (IdxList.size() == 0 ||
1598 (IdxList.size() == 1 && cast<Constant>(IdxList[0])->isNullValue()))
1599 return const_cast<Constant*>(C);
1601 if (isa<UndefValue>(C)) {
1602 const Type *Ty = GetElementPtrInst::getIndexedType(C->getType(), IdxList,
1604 assert(Ty != 0 && "Invalid indices for GEP!");
1605 return UndefValue::get(PointerType::get(Ty));
1608 Constant *Idx0 = cast<Constant>(IdxList[0]);
1609 if (C->isNullValue()) {
1611 for (unsigned i = 0, e = IdxList.size(); i != e; ++i)
1612 if (!cast<Constant>(IdxList[i])->isNullValue()) {
1617 const Type *Ty = GetElementPtrInst::getIndexedType(C->getType(), IdxList,
1619 assert(Ty != 0 && "Invalid indices for GEP!");
1620 return ConstantPointerNull::get(PointerType::get(Ty));
1623 if (IdxList.size() == 1) {
1624 const Type *ElTy = cast<PointerType>(C->getType())->getElementType();
1625 if (uint32_t ElSize = ElTy->getPrimitiveSize()) {
1626 // gep null, C is equal to C*sizeof(nullty). If nullty is a known llvm
1627 // type, we can statically fold this.
1628 Constant *R = ConstantInt::get(Type::UIntTy, ElSize);
1629 R = ConstantExpr::getCast(R, Idx0->getType());
1630 R = ConstantExpr::getMul(R, Idx0);
1631 return ConstantExpr::getCast(R, C->getType());
1636 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(const_cast<Constant*>(C))) {
1637 // Combine Indices - If the source pointer to this getelementptr instruction
1638 // is a getelementptr instruction, combine the indices of the two
1639 // getelementptr instructions into a single instruction.
1641 if (CE->getOpcode() == Instruction::GetElementPtr) {
1642 const Type *LastTy = 0;
1643 for (gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
1647 if ((LastTy && isa<ArrayType>(LastTy)) || Idx0->isNullValue()) {
1648 std::vector<Value*> NewIndices;
1649 NewIndices.reserve(IdxList.size() + CE->getNumOperands());
1650 for (unsigned i = 1, e = CE->getNumOperands()-1; i != e; ++i)
1651 NewIndices.push_back(CE->getOperand(i));
1653 // Add the last index of the source with the first index of the new GEP.
1654 // Make sure to handle the case when they are actually different types.
1655 Constant *Combined = CE->getOperand(CE->getNumOperands()-1);
1656 // Otherwise it must be an array.
1657 if (!Idx0->isNullValue()) {
1658 const Type *IdxTy = Combined->getType();
1659 if (IdxTy != Idx0->getType()) IdxTy = Type::LongTy;
1661 ConstantExpr::get(Instruction::Add,
1662 ConstantExpr::getCast(Idx0, IdxTy),
1663 ConstantExpr::getCast(Combined, IdxTy));
1666 NewIndices.push_back(Combined);
1667 NewIndices.insert(NewIndices.end(), IdxList.begin()+1, IdxList.end());
1668 return ConstantExpr::getGetElementPtr(CE->getOperand(0), NewIndices);
1672 // Implement folding of:
1673 // int* getelementptr ([2 x int]* cast ([3 x int]* %X to [2 x int]*),
1675 // To: int* getelementptr ([3 x int]* %X, long 0, long 0)
1677 if (CE->isCast() && IdxList.size() > 1 && Idx0->isNullValue())
1678 if (const PointerType *SPT =
1679 dyn_cast<PointerType>(CE->getOperand(0)->getType()))
1680 if (const ArrayType *SAT = dyn_cast<ArrayType>(SPT->getElementType()))
1681 if (const ArrayType *CAT =
1682 dyn_cast<ArrayType>(cast<PointerType>(C->getType())->getElementType()))
1683 if (CAT->getElementType() == SAT->getElementType())
1684 return ConstantExpr::getGetElementPtr(
1685 (Constant*)CE->getOperand(0), IdxList);