1 //===- ScalarEvolutionExpander.cpp - Scalar Evolution Analysis --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains the implementation of the scalar evolution expander,
11 // which is used to generate the code corresponding to a given scalar evolution
14 //===----------------------------------------------------------------------===//
16 #include "llvm/Analysis/ScalarEvolutionExpander.h"
17 #include "llvm/Analysis/LoopInfo.h"
18 #include "llvm/Target/TargetData.h"
21 /// InsertCastOfTo - Insert a cast of V to the specified type, doing what
22 /// we can to share the casts.
23 Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V,
25 // Short-circuit unnecessary bitcasts.
26 if (opcode == Instruction::BitCast && V->getType() == Ty)
29 // Short-circuit unnecessary inttoptr<->ptrtoint casts.
30 if ((opcode == Instruction::PtrToInt || opcode == Instruction::IntToPtr) &&
31 SE.getTypeSizeInBits(Ty) == SE.getTypeSizeInBits(V->getType())) {
32 if (CastInst *CI = dyn_cast<CastInst>(V))
33 if ((CI->getOpcode() == Instruction::PtrToInt ||
34 CI->getOpcode() == Instruction::IntToPtr) &&
35 SE.getTypeSizeInBits(CI->getType()) ==
36 SE.getTypeSizeInBits(CI->getOperand(0)->getType()))
37 return CI->getOperand(0);
38 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
39 if ((CE->getOpcode() == Instruction::PtrToInt ||
40 CE->getOpcode() == Instruction::IntToPtr) &&
41 SE.getTypeSizeInBits(CE->getType()) ==
42 SE.getTypeSizeInBits(CE->getOperand(0)->getType()))
43 return CE->getOperand(0);
46 // FIXME: keep track of the cast instruction.
47 if (Constant *C = dyn_cast<Constant>(V))
48 return ConstantExpr::getCast(opcode, C, Ty);
50 if (Argument *A = dyn_cast<Argument>(V)) {
51 // Check to see if there is already a cast!
52 for (Value::use_iterator UI = A->use_begin(), E = A->use_end();
54 if ((*UI)->getType() == Ty)
55 if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI)))
56 if (CI->getOpcode() == opcode) {
57 // If the cast isn't the first instruction of the function, move it.
58 if (BasicBlock::iterator(CI) !=
59 A->getParent()->getEntryBlock().begin()) {
60 // If the CastInst is the insert point, change the insert point.
61 if (CI == InsertPt) ++InsertPt;
62 // Splice the cast at the beginning of the entry block.
63 CI->moveBefore(A->getParent()->getEntryBlock().begin());
68 Instruction *I = CastInst::Create(opcode, V, Ty, V->getName(),
69 A->getParent()->getEntryBlock().begin());
70 InsertedValues.insert(I);
74 Instruction *I = cast<Instruction>(V);
76 // Check to see if there is already a cast. If there is, use it.
77 for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
79 if ((*UI)->getType() == Ty)
80 if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI)))
81 if (CI->getOpcode() == opcode) {
82 BasicBlock::iterator It = I; ++It;
83 if (isa<InvokeInst>(I))
84 It = cast<InvokeInst>(I)->getNormalDest()->begin();
85 while (isa<PHINode>(It)) ++It;
86 if (It != BasicBlock::iterator(CI)) {
87 // If the CastInst is the insert point, change the insert point.
88 if (CI == InsertPt) ++InsertPt;
89 // Splice the cast immediately after the operand in question.
95 BasicBlock::iterator IP = I; ++IP;
96 if (InvokeInst *II = dyn_cast<InvokeInst>(I))
97 IP = II->getNormalDest()->begin();
98 while (isa<PHINode>(IP)) ++IP;
99 Instruction *CI = CastInst::Create(opcode, V, Ty, V->getName(), IP);
100 InsertedValues.insert(CI);
104 /// InsertNoopCastOfTo - Insert a cast of V to the specified type,
105 /// which must be possible with a noop cast.
106 Value *SCEVExpander::InsertNoopCastOfTo(Value *V, const Type *Ty) {
107 Instruction::CastOps Op = CastInst::getCastOpcode(V, false, Ty, false);
108 assert((Op == Instruction::BitCast ||
109 Op == Instruction::PtrToInt ||
110 Op == Instruction::IntToPtr) &&
111 "InsertNoopCastOfTo cannot perform non-noop casts!");
112 assert(SE.getTypeSizeInBits(V->getType()) == SE.getTypeSizeInBits(Ty) &&
113 "InsertNoopCastOfTo cannot change sizes!");
114 return InsertCastOfTo(Op, V, Ty);
117 /// InsertBinop - Insert the specified binary operator, doing a small amount
118 /// of work to avoid inserting an obviously redundant operation.
119 Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS,
120 Value *RHS, BasicBlock::iterator InsertPt) {
121 // Fold a binop with constant operands.
122 if (Constant *CLHS = dyn_cast<Constant>(LHS))
123 if (Constant *CRHS = dyn_cast<Constant>(RHS))
124 return ConstantExpr::get(Opcode, CLHS, CRHS);
126 // Do a quick scan to see if we have this binop nearby. If so, reuse it.
127 unsigned ScanLimit = 6;
128 BasicBlock::iterator BlockBegin = InsertPt->getParent()->begin();
129 if (InsertPt != BlockBegin) {
130 // Scanning starts from the last instruction before InsertPt.
131 BasicBlock::iterator IP = InsertPt;
133 for (; ScanLimit; --IP, --ScanLimit) {
134 if (IP->getOpcode() == (unsigned)Opcode && IP->getOperand(0) == LHS &&
135 IP->getOperand(1) == RHS)
137 if (IP == BlockBegin) break;
141 // If we haven't found this binop, insert it.
142 Instruction *BO = BinaryOperator::Create(Opcode, LHS, RHS, "tmp", InsertPt);
143 InsertedValues.insert(BO);
147 /// FactorOutConstant - Test if S is divisible by Factor, using signed
148 /// division. If so, update S with Factor divided out and return true.
149 /// S need not be evenly divisble if a reasonable remainder can be
151 /// TODO: When ScalarEvolution gets a SCEVSDivExpr, this can be made
152 /// unnecessary; in its place, just signed-divide Ops[i] by the scale and
153 /// check to see if the divide was folded.
154 static bool FactorOutConstant(SCEVHandle &S,
155 SCEVHandle &Remainder,
157 ScalarEvolution &SE) {
158 // Everything is divisible by one.
162 // For a Constant, check for a multiple of the given factor.
163 if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S)) {
165 ConstantInt::get(C->getValue()->getValue().sdiv(Factor));
166 // If the quotient is zero and the remainder is non-zero, reject
167 // the value at this scale. It will be considered for subsequent
169 if (C->isZero() || !CI->isZero()) {
170 SCEVHandle Div = SE.getConstant(CI);
173 SE.getAddExpr(Remainder,
174 SE.getConstant(C->getValue()->getValue().srem(Factor)));
179 // In a Mul, check if there is a constant operand which is a multiple
180 // of the given factor.
181 if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S))
182 if (const SCEVConstant *C = dyn_cast<SCEVConstant>(M->getOperand(0)))
183 if (!C->getValue()->getValue().srem(Factor)) {
184 std::vector<SCEVHandle> NewMulOps(M->getOperands());
186 SE.getConstant(C->getValue()->getValue().sdiv(Factor));
187 S = SE.getMulExpr(NewMulOps);
191 // In an AddRec, check if both start and step are divisible.
192 if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(S)) {
193 SCEVHandle Step = A->getStepRecurrence(SE);
194 SCEVHandle StepRem = SE.getIntegerSCEV(0, Step->getType());
195 if (!FactorOutConstant(Step, StepRem, Factor, SE))
197 if (!StepRem->isZero())
199 SCEVHandle Start = A->getStart();
200 if (!FactorOutConstant(Start, Remainder, Factor, SE))
202 S = SE.getAddRecExpr(Start, Step, A->getLoop());
209 /// expandAddToGEP - Expand a SCEVAddExpr with a pointer type into a GEP
210 /// instead of using ptrtoint+arithmetic+inttoptr. This helps
211 /// BasicAliasAnalysis analyze the result. However, it suffers from the
212 /// underlying bug described in PR2831. Addition in LLVM currently always
213 /// has two's complement wrapping guaranteed. However, the semantics for
214 /// getelementptr overflow are ambiguous. In the common case though, this
215 /// expansion gets used when a GEP in the original code has been converted
216 /// into integer arithmetic, in which case the resulting code will be no
217 /// more undefined than it was originally.
219 /// Design note: It might seem desirable for this function to be more
220 /// loop-aware. If some of the indices are loop-invariant while others
221 /// aren't, it might seem desirable to emit multiple GEPs, keeping the
222 /// loop-invariant portions of the overall computation outside the loop.
223 /// However, there are a few reasons this is not done here. Hoisting simple
224 /// arithmetic is a low-level optimization that often isn't very
225 /// important until late in the optimization process. In fact, passes
226 /// like InstructionCombining will combine GEPs, even if it means
227 /// pushing loop-invariant computation down into loops, so even if the
228 /// GEPs were split here, the work would quickly be undone. The
229 /// LoopStrengthReduction pass, which is usually run quite late (and
230 /// after the last InstructionCombining pass), takes care of hoisting
231 /// loop-invariant portions of expressions, after considering what
232 /// can be folded using target addressing modes.
234 Value *SCEVExpander::expandAddToGEP(const SCEVHandle *op_begin,
235 const SCEVHandle *op_end,
236 const PointerType *PTy,
239 const Type *ElTy = PTy->getElementType();
240 SmallVector<Value *, 4> GepIndices;
241 std::vector<SCEVHandle> Ops(op_begin, op_end);
242 bool AnyNonZeroIndices = false;
244 // Decend down the pointer's type and attempt to convert the other
245 // operands into GEP indices, at each level. The first index in a GEP
246 // indexes into the array implied by the pointer operand; the rest of
247 // the indices index into the element or field type selected by the
250 APInt ElSize = APInt(SE.getTypeSizeInBits(Ty),
251 ElTy->isSized() ? SE.TD->getTypeAllocSize(ElTy) : 0);
252 std::vector<SCEVHandle> NewOps;
253 std::vector<SCEVHandle> ScaledOps;
254 for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
255 // Split AddRecs up into parts as either of the parts may be usable
256 // without the other.
257 if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(Ops[i]))
258 if (!A->getStart()->isZero()) {
259 SCEVHandle Start = A->getStart();
260 Ops.push_back(SE.getAddRecExpr(SE.getIntegerSCEV(0, A->getType()),
261 A->getStepRecurrence(SE),
266 // If the scale size is not 0, attempt to factor out a scale.
268 SCEVHandle Op = Ops[i];
269 SCEVHandle Remainder = SE.getIntegerSCEV(0, Op->getType());
270 if (FactorOutConstant(Op, Remainder, ElSize, SE)) {
271 ScaledOps.push_back(Op); // Op now has ElSize factored out.
272 NewOps.push_back(Remainder);
276 // If the operand was not divisible, add it to the list of operands
277 // we'll scan next iteration.
278 NewOps.push_back(Ops[i]);
281 AnyNonZeroIndices |= !ScaledOps.empty();
282 Value *Scaled = ScaledOps.empty() ?
283 Constant::getNullValue(Ty) :
284 expandCodeFor(SE.getAddExpr(ScaledOps), Ty);
285 GepIndices.push_back(Scaled);
287 // Collect struct field index operands.
289 while (const StructType *STy = dyn_cast<StructType>(ElTy)) {
290 if (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[0]))
291 if (SE.getTypeSizeInBits(C->getType()) <= 64) {
292 const StructLayout &SL = *SE.TD->getStructLayout(STy);
293 uint64_t FullOffset = C->getValue()->getZExtValue();
294 if (FullOffset < SL.getSizeInBytes()) {
295 unsigned ElIdx = SL.getElementContainingOffset(FullOffset);
296 GepIndices.push_back(ConstantInt::get(Type::Int32Ty, ElIdx));
297 ElTy = STy->getTypeAtIndex(ElIdx);
299 SE.getConstant(ConstantInt::get(Ty,
301 SL.getElementOffset(ElIdx)));
302 AnyNonZeroIndices = true;
309 if (const ArrayType *ATy = dyn_cast<ArrayType>(ElTy)) {
310 ElTy = ATy->getElementType();
316 // If none of the operands were convertable to proper GEP indices, cast
317 // the base to i8* and do an ugly getelementptr with that. It's still
318 // better than ptrtoint+arithmetic+inttoptr at least.
319 if (!AnyNonZeroIndices) {
320 V = InsertNoopCastOfTo(V,
321 Type::Int8Ty->getPointerTo(PTy->getAddressSpace()));
322 Value *Idx = expand(SE.getAddExpr(Ops));
323 Idx = InsertNoopCastOfTo(Idx, Ty);
325 // Fold a GEP with constant operands.
326 if (Constant *CLHS = dyn_cast<Constant>(V))
327 if (Constant *CRHS = dyn_cast<Constant>(Idx))
328 return ConstantExpr::getGetElementPtr(CLHS, &CRHS, 1);
330 // Do a quick scan to see if we have this GEP nearby. If so, reuse it.
331 unsigned ScanLimit = 6;
332 BasicBlock::iterator BlockBegin = InsertPt->getParent()->begin();
333 if (InsertPt != BlockBegin) {
334 // Scanning starts from the last instruction before InsertPt.
335 BasicBlock::iterator IP = InsertPt;
337 for (; ScanLimit; --IP, --ScanLimit) {
338 if (IP->getOpcode() == Instruction::GetElementPtr &&
339 IP->getOperand(0) == V && IP->getOperand(1) == Idx)
341 if (IP == BlockBegin) break;
345 Value *GEP = GetElementPtrInst::Create(V, Idx, "scevgep", InsertPt);
346 InsertedValues.insert(GEP);
350 // Insert a pretty getelementptr.
351 Value *GEP = GetElementPtrInst::Create(V,
354 "scevgep", InsertPt);
355 Ops.push_back(SE.getUnknown(GEP));
356 InsertedValues.insert(GEP);
357 return expand(SE.getAddExpr(Ops));
360 Value *SCEVExpander::visitAddExpr(const SCEVAddExpr *S) {
361 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
362 Value *V = expand(S->getOperand(S->getNumOperands()-1));
364 // Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the
365 // comments on expandAddToGEP for details.
367 if (const PointerType *PTy = dyn_cast<PointerType>(V->getType())) {
368 const std::vector<SCEVHandle> &Ops = S->getOperands();
369 return expandAddToGEP(&Ops[0], &Ops[Ops.size() - 1],
373 V = InsertNoopCastOfTo(V, Ty);
375 // Emit a bunch of add instructions
376 for (int i = S->getNumOperands()-2; i >= 0; --i) {
377 Value *W = expand(S->getOperand(i));
378 W = InsertNoopCastOfTo(W, Ty);
379 V = InsertBinop(Instruction::Add, V, W, InsertPt);
384 Value *SCEVExpander::visitMulExpr(const SCEVMulExpr *S) {
385 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
386 int FirstOp = 0; // Set if we should emit a subtract.
387 if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getOperand(0)))
388 if (SC->getValue()->isAllOnesValue())
391 int i = S->getNumOperands()-2;
392 Value *V = expand(S->getOperand(i+1));
393 V = InsertNoopCastOfTo(V, Ty);
395 // Emit a bunch of multiply instructions
396 for (; i >= FirstOp; --i) {
397 Value *W = expand(S->getOperand(i));
398 W = InsertNoopCastOfTo(W, Ty);
399 V = InsertBinop(Instruction::Mul, V, W, InsertPt);
402 // -1 * ... ---> 0 - ...
404 V = InsertBinop(Instruction::Sub, Constant::getNullValue(Ty), V, InsertPt);
408 Value *SCEVExpander::visitUDivExpr(const SCEVUDivExpr *S) {
409 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
411 Value *LHS = expand(S->getLHS());
412 LHS = InsertNoopCastOfTo(LHS, Ty);
413 if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getRHS())) {
414 const APInt &RHS = SC->getValue()->getValue();
415 if (RHS.isPowerOf2())
416 return InsertBinop(Instruction::LShr, LHS,
417 ConstantInt::get(Ty, RHS.logBase2()),
421 Value *RHS = expand(S->getRHS());
422 RHS = InsertNoopCastOfTo(RHS, Ty);
423 return InsertBinop(Instruction::UDiv, LHS, RHS, InsertPt);
426 /// Move parts of Base into Rest to leave Base with the minimal
427 /// expression that provides a pointer operand suitable for a
429 static void ExposePointerBase(SCEVHandle &Base, SCEVHandle &Rest,
430 ScalarEvolution &SE) {
431 while (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(Base)) {
432 Base = A->getStart();
433 Rest = SE.getAddExpr(Rest,
434 SE.getAddRecExpr(SE.getIntegerSCEV(0, A->getType()),
435 A->getStepRecurrence(SE),
438 if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(Base)) {
439 Base = A->getOperand(A->getNumOperands()-1);
440 std::vector<SCEVHandle> NewAddOps(A->op_begin(), A->op_end());
441 NewAddOps.back() = Rest;
442 Rest = SE.getAddExpr(NewAddOps);
443 ExposePointerBase(Base, Rest, SE);
447 Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
448 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
449 const Loop *L = S->getLoop();
451 // {X,+,F} --> X + {0,+,F}
452 if (!S->getStart()->isZero()) {
453 std::vector<SCEVHandle> NewOps(S->getOperands());
454 NewOps[0] = SE.getIntegerSCEV(0, Ty);
455 SCEVHandle Rest = SE.getAddRecExpr(NewOps, L);
457 // Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the
458 // comments on expandAddToGEP for details.
460 SCEVHandle Base = S->getStart();
461 SCEVHandle RestArray[1] = Rest;
462 // Dig into the expression to find the pointer base for a GEP.
463 ExposePointerBase(Base, RestArray[0], SE);
464 // If we found a pointer, expand the AddRec with a GEP.
465 if (const PointerType *PTy = dyn_cast<PointerType>(Base->getType())) {
466 // Make sure the Base isn't something exotic, such as a multiplied
467 // or divided pointer value. In those cases, the result type isn't
468 // actually a pointer type.
469 if (!isa<SCEVMulExpr>(Base) && !isa<SCEVUDivExpr>(Base)) {
470 Value *StartV = expand(Base);
471 assert(StartV->getType() == PTy && "Pointer type mismatch for GEP!");
472 return expandAddToGEP(RestArray, RestArray+1, PTy, Ty, StartV);
477 Value *RestV = expand(Rest);
478 return expand(SE.getAddExpr(S->getStart(), SE.getUnknown(RestV)));
481 // {0,+,1} --> Insert a canonical induction variable into the loop!
483 S->getOperand(1) == SE.getIntegerSCEV(1, Ty)) {
484 // Create and insert the PHI node for the induction variable in the
486 BasicBlock *Header = L->getHeader();
487 PHINode *PN = PHINode::Create(Ty, "indvar", Header->begin());
488 InsertedValues.insert(PN);
489 PN->addIncoming(Constant::getNullValue(Ty), L->getLoopPreheader());
491 pred_iterator HPI = pred_begin(Header);
492 assert(HPI != pred_end(Header) && "Loop with zero preds???");
493 if (!L->contains(*HPI)) ++HPI;
494 assert(HPI != pred_end(Header) && L->contains(*HPI) &&
495 "No backedge in loop?");
497 // Insert a unit add instruction right before the terminator corresponding
499 Constant *One = ConstantInt::get(Ty, 1);
500 Instruction *Add = BinaryOperator::CreateAdd(PN, One, "indvar.next",
501 (*HPI)->getTerminator());
502 InsertedValues.insert(Add);
504 pred_iterator PI = pred_begin(Header);
505 if (*PI == L->getLoopPreheader())
507 PN->addIncoming(Add, *PI);
511 // Get the canonical induction variable I for this loop.
512 Value *I = getOrInsertCanonicalInductionVariable(L, Ty);
514 // If this is a simple linear addrec, emit it now as a special case.
515 if (S->isAffine()) { // {0,+,F} --> i*F
516 Value *F = expand(S->getOperand(1));
517 F = InsertNoopCastOfTo(F, Ty);
519 // IF the step is by one, just return the inserted IV.
520 if (ConstantInt *CI = dyn_cast<ConstantInt>(F))
521 if (CI->getValue() == 1)
524 // If the insert point is directly inside of the loop, emit the multiply at
525 // the insert point. Otherwise, L is a loop that is a parent of the insert
526 // point loop. If we can, move the multiply to the outer most loop that it
528 BasicBlock::iterator MulInsertPt = getInsertionPoint();
529 Loop *InsertPtLoop = SE.LI->getLoopFor(MulInsertPt->getParent());
530 if (InsertPtLoop != L && InsertPtLoop &&
531 L->contains(InsertPtLoop->getHeader())) {
533 // If we cannot hoist the multiply out of this loop, don't.
534 if (!InsertPtLoop->isLoopInvariant(F)) break;
536 BasicBlock *InsertPtLoopPH = InsertPtLoop->getLoopPreheader();
538 // If this loop hasn't got a preheader, we aren't able to hoist the
543 // Otherwise, move the insert point to the preheader.
544 MulInsertPt = InsertPtLoopPH->getTerminator();
545 InsertPtLoop = InsertPtLoop->getParentLoop();
546 } while (InsertPtLoop != L);
549 return InsertBinop(Instruction::Mul, I, F, MulInsertPt);
552 // If this is a chain of recurrences, turn it into a closed form, using the
553 // folders, then expandCodeFor the closed form. This allows the folders to
554 // simplify the expression without having to build a bunch of special code
556 SCEVHandle IH = SE.getUnknown(I); // Get I as a "symbolic" SCEV.
558 SCEVHandle V = S->evaluateAtIteration(IH, SE);
559 //cerr << "Evaluated: " << *this << "\n to: " << *V << "\n";
564 Value *SCEVExpander::visitTruncateExpr(const SCEVTruncateExpr *S) {
565 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
566 Value *V = expand(S->getOperand());
567 V = InsertNoopCastOfTo(V, SE.getEffectiveSCEVType(V->getType()));
568 Instruction *I = new TruncInst(V, Ty, "tmp.", InsertPt);
569 InsertedValues.insert(I);
573 Value *SCEVExpander::visitZeroExtendExpr(const SCEVZeroExtendExpr *S) {
574 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
575 Value *V = expand(S->getOperand());
576 V = InsertNoopCastOfTo(V, SE.getEffectiveSCEVType(V->getType()));
577 Instruction *I = new ZExtInst(V, Ty, "tmp.", InsertPt);
578 InsertedValues.insert(I);
582 Value *SCEVExpander::visitSignExtendExpr(const SCEVSignExtendExpr *S) {
583 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
584 Value *V = expand(S->getOperand());
585 V = InsertNoopCastOfTo(V, SE.getEffectiveSCEVType(V->getType()));
586 Instruction *I = new SExtInst(V, Ty, "tmp.", InsertPt);
587 InsertedValues.insert(I);
591 Value *SCEVExpander::visitSMaxExpr(const SCEVSMaxExpr *S) {
592 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
593 Value *LHS = expand(S->getOperand(0));
594 LHS = InsertNoopCastOfTo(LHS, Ty);
595 for (unsigned i = 1; i < S->getNumOperands(); ++i) {
596 Value *RHS = expand(S->getOperand(i));
597 RHS = InsertNoopCastOfTo(RHS, Ty);
599 new ICmpInst(ICmpInst::ICMP_SGT, LHS, RHS, "tmp", InsertPt);
600 InsertedValues.insert(ICmp);
601 Instruction *Sel = SelectInst::Create(ICmp, LHS, RHS, "smax", InsertPt);
602 InsertedValues.insert(Sel);
608 Value *SCEVExpander::visitUMaxExpr(const SCEVUMaxExpr *S) {
609 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
610 Value *LHS = expand(S->getOperand(0));
611 LHS = InsertNoopCastOfTo(LHS, Ty);
612 for (unsigned i = 1; i < S->getNumOperands(); ++i) {
613 Value *RHS = expand(S->getOperand(i));
614 RHS = InsertNoopCastOfTo(RHS, Ty);
616 new ICmpInst(ICmpInst::ICMP_UGT, LHS, RHS, "tmp", InsertPt);
617 InsertedValues.insert(ICmp);
618 Instruction *Sel = SelectInst::Create(ICmp, LHS, RHS, "umax", InsertPt);
619 InsertedValues.insert(Sel);
625 Value *SCEVExpander::expandCodeFor(SCEVHandle SH, const Type *Ty) {
626 // Expand the code for this SCEV.
627 Value *V = expand(SH);
629 assert(SE.getTypeSizeInBits(Ty) == SE.getTypeSizeInBits(SH->getType()) &&
630 "non-trivial casts should be done with the SCEVs directly!");
631 V = InsertNoopCastOfTo(V, Ty);
636 Value *SCEVExpander::expand(const SCEV *S) {
637 // Check to see if we already expanded this.
638 std::map<SCEVHandle, AssertingVH<Value> >::iterator I =
639 InsertedExpressions.find(S);
640 if (I != InsertedExpressions.end())
644 InsertedExpressions[S] = V;