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 evenly divisible by Factor, using signed
148 /// division. If so, update S with Factor divided out and return true.
149 /// TODO: When ScalarEvolution gets a SCEVSDivExpr, this can be made
150 /// unnecessary; in its place, just signed-divide Ops[i] by the scale and
151 /// check to see if the divide was folded.
152 static bool FactorOutConstant(SCEVHandle &S,
154 ScalarEvolution &SE) {
155 // Everything is divisible by one.
159 // For a Constant, check for a multiple of the given factor.
160 if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S))
161 if (!C->getValue()->getValue().srem(Factor)) {
163 ConstantInt::get(C->getValue()->getValue().sdiv(Factor));
164 SCEVHandle Div = SE.getConstant(CI);
169 // In a Mul, check if there is a constant operand which is a multiple
170 // of the given factor.
171 if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S))
172 if (const SCEVConstant *C = dyn_cast<SCEVConstant>(M->getOperand(0)))
173 if (!C->getValue()->getValue().srem(Factor)) {
174 std::vector<SCEVHandle> NewMulOps(M->getOperands());
176 SE.getConstant(C->getValue()->getValue().sdiv(Factor));
177 S = SE.getMulExpr(NewMulOps);
181 // In an AddRec, check if both start and step are divisible.
182 if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(S)) {
183 SCEVHandle Start = A->getStart();
184 if (!FactorOutConstant(Start, Factor, SE))
186 SCEVHandle Step = A->getStepRecurrence(SE);
187 if (!FactorOutConstant(Step, Factor, SE))
189 S = SE.getAddRecExpr(Start, Step, A->getLoop());
196 /// expandAddToGEP - Expand a SCEVAddExpr with a pointer type into a GEP
197 /// instead of using ptrtoint+arithmetic+inttoptr. This helps
198 /// BasicAliasAnalysis analyze the result. However, it suffers from the
199 /// underlying bug described in PR2831. Addition in LLVM currently always
200 /// has two's complement wrapping guaranteed. However, the semantics for
201 /// getelementptr overflow are ambiguous. In the common case though, this
202 /// expansion gets used when a GEP in the original code has been converted
203 /// into integer arithmetic, in which case the resulting code will be no
204 /// more undefined than it was originally.
206 /// Design note: It might seem desirable for this function to be more
207 /// loop-aware. If some of the indices are loop-invariant while others
208 /// aren't, it might seem desirable to emit multiple GEPs, keeping the
209 /// loop-invariant portions of the overall computation outside the loop.
210 /// However, there are a few reasons this is not done here. Hoisting simple
211 /// arithmetic is a low-level optimization that often isn't very
212 /// important until late in the optimization process. In fact, passes
213 /// like InstructionCombining will combine GEPs, even if it means
214 /// pushing loop-invariant computation down into loops, so even if the
215 /// GEPs were split here, the work would quickly be undone. The
216 /// LoopStrengthReduction pass, which is usually run quite late (and
217 /// after the last InstructionCombining pass), takes care of hoisting
218 /// loop-invariant portions of expressions, after considering what
219 /// can be folded using target addressing modes.
221 Value *SCEVExpander::expandAddToGEP(const SCEVHandle *op_begin,
222 const SCEVHandle *op_end,
223 const PointerType *PTy,
226 const Type *ElTy = PTy->getElementType();
227 SmallVector<Value *, 4> GepIndices;
228 std::vector<SCEVHandle> Ops(op_begin, op_end);
229 bool AnyNonZeroIndices = false;
231 // Decend down the pointer's type and attempt to convert the other
232 // operands into GEP indices, at each level. The first index in a GEP
233 // indexes into the array implied by the pointer operand; the rest of
234 // the indices index into the element or field type selected by the
237 APInt ElSize = APInt(SE.getTypeSizeInBits(Ty),
238 ElTy->isSized() ? SE.TD->getTypeAllocSize(ElTy) : 0);
239 std::vector<SCEVHandle> NewOps;
240 std::vector<SCEVHandle> ScaledOps;
241 for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
242 // Split AddRecs up into parts as either of the parts may be usable
243 // without the other.
244 if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(Ops[i]))
245 if (!A->getStart()->isZero()) {
246 SCEVHandle Start = A->getStart();
247 Ops.push_back(SE.getAddRecExpr(SE.getIntegerSCEV(0, A->getType()),
248 A->getStepRecurrence(SE),
253 // If the scale size is not 0, attempt to factor out a scale.
255 SCEVHandle Op = Ops[i];
256 if (FactorOutConstant(Op, ElSize, SE)) {
257 ScaledOps.push_back(Op); // Op now has ElSize factored out.
261 // If the operand was not divisible, add it to the list of operands
262 // we'll scan next iteration.
263 NewOps.push_back(Ops[i]);
266 AnyNonZeroIndices |= !ScaledOps.empty();
267 Value *Scaled = ScaledOps.empty() ?
268 Constant::getNullValue(Ty) :
269 expandCodeFor(SE.getAddExpr(ScaledOps), Ty);
270 GepIndices.push_back(Scaled);
272 // Collect struct field index operands.
274 while (const StructType *STy = dyn_cast<StructType>(ElTy)) {
275 if (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[0]))
276 if (SE.getTypeSizeInBits(C->getType()) <= 64) {
277 const StructLayout &SL = *SE.TD->getStructLayout(STy);
278 uint64_t FullOffset = C->getValue()->getZExtValue();
279 if (FullOffset < SL.getSizeInBytes()) {
280 unsigned ElIdx = SL.getElementContainingOffset(FullOffset);
281 GepIndices.push_back(ConstantInt::get(Type::Int32Ty, ElIdx));
282 ElTy = STy->getTypeAtIndex(ElIdx);
284 SE.getConstant(ConstantInt::get(Ty,
286 SL.getElementOffset(ElIdx)));
287 AnyNonZeroIndices = true;
294 if (const ArrayType *ATy = dyn_cast<ArrayType>(ElTy)) {
295 ElTy = ATy->getElementType();
301 // If none of the operands were convertable to proper GEP indices, cast
302 // the base to i8* and do an ugly getelementptr with that. It's still
303 // better than ptrtoint+arithmetic+inttoptr at least.
304 if (!AnyNonZeroIndices) {
305 V = InsertNoopCastOfTo(V,
306 Type::Int8Ty->getPointerTo(PTy->getAddressSpace()));
307 Value *Idx = expand(SE.getAddExpr(Ops));
308 Idx = InsertNoopCastOfTo(Idx, Ty);
310 // Fold a GEP with constant operands.
311 if (Constant *CLHS = dyn_cast<Constant>(V))
312 if (Constant *CRHS = dyn_cast<Constant>(Idx))
313 return ConstantExpr::getGetElementPtr(CLHS, &CRHS, 1);
315 // Do a quick scan to see if we have this GEP nearby. If so, reuse it.
316 unsigned ScanLimit = 6;
317 BasicBlock::iterator BlockBegin = InsertPt->getParent()->begin();
318 if (InsertPt != BlockBegin) {
319 // Scanning starts from the last instruction before InsertPt.
320 BasicBlock::iterator IP = InsertPt;
322 for (; ScanLimit; --IP, --ScanLimit) {
323 if (IP->getOpcode() == Instruction::GetElementPtr &&
324 IP->getOperand(0) == V && IP->getOperand(1) == Idx)
326 if (IP == BlockBegin) break;
330 Value *GEP = GetElementPtrInst::Create(V, Idx, "scevgep", InsertPt);
331 InsertedValues.insert(GEP);
335 // Insert a pretty getelementptr.
336 Value *GEP = GetElementPtrInst::Create(V,
339 "scevgep", InsertPt);
340 Ops.push_back(SE.getUnknown(GEP));
341 InsertedValues.insert(GEP);
342 return expand(SE.getAddExpr(Ops));
345 Value *SCEVExpander::visitAddExpr(const SCEVAddExpr *S) {
346 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
347 Value *V = expand(S->getOperand(S->getNumOperands()-1));
349 // Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the
350 // comments on expandAddToGEP for details.
352 if (const PointerType *PTy = dyn_cast<PointerType>(V->getType())) {
353 const std::vector<SCEVHandle> &Ops = S->getOperands();
354 return expandAddToGEP(&Ops[0], &Ops[Ops.size() - 1],
358 V = InsertNoopCastOfTo(V, Ty);
360 // Emit a bunch of add instructions
361 for (int i = S->getNumOperands()-2; i >= 0; --i) {
362 Value *W = expand(S->getOperand(i));
363 W = InsertNoopCastOfTo(W, Ty);
364 V = InsertBinop(Instruction::Add, V, W, InsertPt);
369 Value *SCEVExpander::visitMulExpr(const SCEVMulExpr *S) {
370 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
371 int FirstOp = 0; // Set if we should emit a subtract.
372 if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getOperand(0)))
373 if (SC->getValue()->isAllOnesValue())
376 int i = S->getNumOperands()-2;
377 Value *V = expand(S->getOperand(i+1));
378 V = InsertNoopCastOfTo(V, Ty);
380 // Emit a bunch of multiply instructions
381 for (; i >= FirstOp; --i) {
382 Value *W = expand(S->getOperand(i));
383 W = InsertNoopCastOfTo(W, Ty);
384 V = InsertBinop(Instruction::Mul, V, W, InsertPt);
387 // -1 * ... ---> 0 - ...
389 V = InsertBinop(Instruction::Sub, Constant::getNullValue(Ty), V, InsertPt);
393 Value *SCEVExpander::visitUDivExpr(const SCEVUDivExpr *S) {
394 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
396 Value *LHS = expand(S->getLHS());
397 LHS = InsertNoopCastOfTo(LHS, Ty);
398 if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getRHS())) {
399 const APInt &RHS = SC->getValue()->getValue();
400 if (RHS.isPowerOf2())
401 return InsertBinop(Instruction::LShr, LHS,
402 ConstantInt::get(Ty, RHS.logBase2()),
406 Value *RHS = expand(S->getRHS());
407 RHS = InsertNoopCastOfTo(RHS, Ty);
408 return InsertBinop(Instruction::UDiv, LHS, RHS, InsertPt);
411 /// Move parts of Base into Rest to leave Base with the minimal
412 /// expression that provides a pointer operand suitable for a
414 static void ExposePointerBase(SCEVHandle &Base, SCEVHandle &Rest,
415 ScalarEvolution &SE) {
416 while (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(Base)) {
417 Base = A->getStart();
418 Rest = SE.getAddExpr(Rest,
419 SE.getAddRecExpr(SE.getIntegerSCEV(0, A->getType()),
420 A->getStepRecurrence(SE),
423 if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(Base)) {
424 Base = A->getOperand(A->getNumOperands()-1);
425 std::vector<SCEVHandle> NewAddOps(A->op_begin(), A->op_end());
426 NewAddOps.back() = Rest;
427 Rest = SE.getAddExpr(NewAddOps);
428 ExposePointerBase(Base, Rest, SE);
432 Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
433 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
434 const Loop *L = S->getLoop();
436 // {X,+,F} --> X + {0,+,F}
437 if (!S->getStart()->isZero()) {
438 std::vector<SCEVHandle> NewOps(S->getOperands());
439 NewOps[0] = SE.getIntegerSCEV(0, Ty);
440 SCEVHandle Rest = SE.getAddRecExpr(NewOps, L);
442 // Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the
443 // comments on expandAddToGEP for details.
445 SCEVHandle Base = S->getStart();
446 SCEVHandle RestArray[1] = Rest;
447 // Dig into the expression to find the pointer base for a GEP.
448 ExposePointerBase(Base, RestArray[0], SE);
449 // If we found a pointer, expand the AddRec with a GEP.
450 if (const PointerType *PTy = dyn_cast<PointerType>(Base->getType())) {
451 // Make sure the Base isn't something exotic, such as a multiplied
452 // or divided pointer value. In those cases, the result type isn't
453 // actually a pointer type.
454 if (!isa<SCEVMulExpr>(Base) && !isa<SCEVUDivExpr>(Base)) {
455 Value *StartV = expand(Base);
456 assert(StartV->getType() == PTy && "Pointer type mismatch for GEP!");
457 return expandAddToGEP(RestArray, RestArray+1, PTy, Ty, StartV);
462 Value *RestV = expand(Rest);
463 return expand(SE.getAddExpr(S->getStart(), SE.getUnknown(RestV)));
466 // {0,+,1} --> Insert a canonical induction variable into the loop!
468 S->getOperand(1) == SE.getIntegerSCEV(1, Ty)) {
469 // Create and insert the PHI node for the induction variable in the
471 BasicBlock *Header = L->getHeader();
472 PHINode *PN = PHINode::Create(Ty, "indvar", Header->begin());
473 InsertedValues.insert(PN);
474 PN->addIncoming(Constant::getNullValue(Ty), L->getLoopPreheader());
476 pred_iterator HPI = pred_begin(Header);
477 assert(HPI != pred_end(Header) && "Loop with zero preds???");
478 if (!L->contains(*HPI)) ++HPI;
479 assert(HPI != pred_end(Header) && L->contains(*HPI) &&
480 "No backedge in loop?");
482 // Insert a unit add instruction right before the terminator corresponding
484 Constant *One = ConstantInt::get(Ty, 1);
485 Instruction *Add = BinaryOperator::CreateAdd(PN, One, "indvar.next",
486 (*HPI)->getTerminator());
487 InsertedValues.insert(Add);
489 pred_iterator PI = pred_begin(Header);
490 if (*PI == L->getLoopPreheader())
492 PN->addIncoming(Add, *PI);
496 // Get the canonical induction variable I for this loop.
497 Value *I = getOrInsertCanonicalInductionVariable(L, Ty);
499 // If this is a simple linear addrec, emit it now as a special case.
500 if (S->isAffine()) { // {0,+,F} --> i*F
501 Value *F = expand(S->getOperand(1));
502 F = InsertNoopCastOfTo(F, Ty);
504 // IF the step is by one, just return the inserted IV.
505 if (ConstantInt *CI = dyn_cast<ConstantInt>(F))
506 if (CI->getValue() == 1)
509 // If the insert point is directly inside of the loop, emit the multiply at
510 // the insert point. Otherwise, L is a loop that is a parent of the insert
511 // point loop. If we can, move the multiply to the outer most loop that it
513 BasicBlock::iterator MulInsertPt = getInsertionPoint();
514 Loop *InsertPtLoop = SE.LI->getLoopFor(MulInsertPt->getParent());
515 if (InsertPtLoop != L && InsertPtLoop &&
516 L->contains(InsertPtLoop->getHeader())) {
518 // If we cannot hoist the multiply out of this loop, don't.
519 if (!InsertPtLoop->isLoopInvariant(F)) break;
521 BasicBlock *InsertPtLoopPH = InsertPtLoop->getLoopPreheader();
523 // If this loop hasn't got a preheader, we aren't able to hoist the
528 // Otherwise, move the insert point to the preheader.
529 MulInsertPt = InsertPtLoopPH->getTerminator();
530 InsertPtLoop = InsertPtLoop->getParentLoop();
531 } while (InsertPtLoop != L);
534 return InsertBinop(Instruction::Mul, I, F, MulInsertPt);
537 // If this is a chain of recurrences, turn it into a closed form, using the
538 // folders, then expandCodeFor the closed form. This allows the folders to
539 // simplify the expression without having to build a bunch of special code
541 SCEVHandle IH = SE.getUnknown(I); // Get I as a "symbolic" SCEV.
543 SCEVHandle V = S->evaluateAtIteration(IH, SE);
544 //cerr << "Evaluated: " << *this << "\n to: " << *V << "\n";
549 Value *SCEVExpander::visitTruncateExpr(const SCEVTruncateExpr *S) {
550 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
551 Value *V = expand(S->getOperand());
552 V = InsertNoopCastOfTo(V, SE.getEffectiveSCEVType(V->getType()));
553 Instruction *I = new TruncInst(V, Ty, "tmp.", InsertPt);
554 InsertedValues.insert(I);
558 Value *SCEVExpander::visitZeroExtendExpr(const SCEVZeroExtendExpr *S) {
559 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
560 Value *V = expand(S->getOperand());
561 V = InsertNoopCastOfTo(V, SE.getEffectiveSCEVType(V->getType()));
562 Instruction *I = new ZExtInst(V, Ty, "tmp.", InsertPt);
563 InsertedValues.insert(I);
567 Value *SCEVExpander::visitSignExtendExpr(const SCEVSignExtendExpr *S) {
568 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
569 Value *V = expand(S->getOperand());
570 V = InsertNoopCastOfTo(V, SE.getEffectiveSCEVType(V->getType()));
571 Instruction *I = new SExtInst(V, Ty, "tmp.", InsertPt);
572 InsertedValues.insert(I);
576 Value *SCEVExpander::visitSMaxExpr(const SCEVSMaxExpr *S) {
577 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
578 Value *LHS = expand(S->getOperand(0));
579 LHS = InsertNoopCastOfTo(LHS, Ty);
580 for (unsigned i = 1; i < S->getNumOperands(); ++i) {
581 Value *RHS = expand(S->getOperand(i));
582 RHS = InsertNoopCastOfTo(RHS, Ty);
584 new ICmpInst(ICmpInst::ICMP_SGT, LHS, RHS, "tmp", InsertPt);
585 InsertedValues.insert(ICmp);
586 Instruction *Sel = SelectInst::Create(ICmp, LHS, RHS, "smax", InsertPt);
587 InsertedValues.insert(Sel);
593 Value *SCEVExpander::visitUMaxExpr(const SCEVUMaxExpr *S) {
594 const Type *Ty = SE.getEffectiveSCEVType(S->getType());
595 Value *LHS = expand(S->getOperand(0));
596 LHS = InsertNoopCastOfTo(LHS, Ty);
597 for (unsigned i = 1; i < S->getNumOperands(); ++i) {
598 Value *RHS = expand(S->getOperand(i));
599 RHS = InsertNoopCastOfTo(RHS, Ty);
601 new ICmpInst(ICmpInst::ICMP_UGT, LHS, RHS, "tmp", InsertPt);
602 InsertedValues.insert(ICmp);
603 Instruction *Sel = SelectInst::Create(ICmp, LHS, RHS, "umax", InsertPt);
604 InsertedValues.insert(Sel);
610 Value *SCEVExpander::expandCodeFor(SCEVHandle SH, const Type *Ty) {
611 // Expand the code for this SCEV.
612 Value *V = expand(SH);
614 assert(SE.getTypeSizeInBits(Ty) == SE.getTypeSizeInBits(SH->getType()) &&
615 "non-trivial casts should be done with the SCEVs directly!");
616 V = InsertNoopCastOfTo(V, Ty);
621 Value *SCEVExpander::expand(const SCEV *S) {
622 // Check to see if we already expanded this.
623 std::map<SCEVHandle, AssertingVH<Value> >::iterator I =
624 InsertedExpressions.find(S);
625 if (I != InsertedExpressions.end())
629 InsertedExpressions[S] = V;