//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "iv-users"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/CodeMetrics.h"
#include "llvm/Analysis/IVUsers.h"
-#include "llvm/Constants.h"
-#include "llvm/Instructions.h"
-#include "llvm/Type.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
-#include "llvm/Assembly/AsmAnnotationWriter.h"
-#include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
using namespace llvm;
+#define DEBUG_TYPE "iv-users"
+
char IVUsers::ID = 0;
-static RegisterPass<IVUsers>
-X("iv-users", "Induction Variable Users", false, true);
+INITIALIZE_PASS_BEGIN(IVUsers, "iv-users",
+ "Induction Variable Users", false, true)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
+INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
+INITIALIZE_PASS_END(IVUsers, "iv-users",
+ "Induction Variable Users", false, true)
Pass *llvm::createIVUsersPass() {
return new IVUsers();
}
-/// CollectSubexprs - Split S into subexpressions which can be pulled out into
-/// separate registers.
-static void CollectSubexprs(const SCEV *S,
- SmallVectorImpl<const SCEV *> &Ops,
- ScalarEvolution &SE) {
- if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
- // Break out add operands.
- for (SCEVAddExpr::op_iterator I = Add->op_begin(), E = Add->op_end();
- I != E; ++I)
- CollectSubexprs(*I, Ops, SE);
- return;
- } else if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
- // Split a non-zero base out of an addrec.
- if (!AR->getStart()->isZero()) {
- CollectSubexprs(AR->getStart(), Ops, SE);
- CollectSubexprs(SE.getAddRecExpr(SE.getIntegerSCEV(0, AR->getType()),
- AR->getStepRecurrence(SE),
- AR->getLoop()), Ops, SE);
- return;
- }
- }
-
- // Otherwise use the value itself.
- Ops.push_back(S);
-}
-
-/// getSCEVStartAndStride - Compute the start and stride of this expression,
-/// returning false if the expression is not a start/stride pair, or true if it
-/// is. The stride must be a loop invariant expression, but the start may be
-/// a mix of loop invariant and loop variant expressions. The start cannot,
-/// however, contain an AddRec from a different loop, unless that loop is an
-/// outer loop of the current loop.
-static bool getSCEVStartAndStride(const SCEV *&SH, Loop *L, Loop *UseLoop,
- const SCEV *&Start, const SCEV *&Stride,
- ScalarEvolution *SE, DominatorTree *DT) {
- const SCEV *TheAddRec = Start; // Initialize to zero.
-
- // If the outer level is an AddExpr, the operands are all start values except
- // for a nested AddRecExpr.
- if (const SCEVAddExpr *AE = dyn_cast<SCEVAddExpr>(SH)) {
- for (unsigned i = 0, e = AE->getNumOperands(); i != e; ++i)
- if (const SCEVAddRecExpr *AddRec =
- dyn_cast<SCEVAddRecExpr>(AE->getOperand(i)))
- TheAddRec = SE->getAddExpr(AddRec, TheAddRec);
- else
- Start = SE->getAddExpr(Start, AE->getOperand(i));
- } else if (isa<SCEVAddRecExpr>(SH)) {
- TheAddRec = SH;
- } else {
- return false; // not analyzable.
+/// isInteresting - Test whether the given expression is "interesting" when
+/// used by the given expression, within the context of analyzing the
+/// given loop.
+static bool isInteresting(const SCEV *S, const Instruction *I, const Loop *L,
+ ScalarEvolution *SE, LoopInfo *LI) {
+ // An addrec is interesting if it's affine or if it has an interesting start.
+ if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
+ // Keep things simple. Don't touch loop-variant strides unless they're
+ // only used outside the loop and we can simplify them.
+ if (AR->getLoop() == L)
+ return AR->isAffine() ||
+ (!L->contains(I) &&
+ SE->getSCEVAtScope(AR, LI->getLoopFor(I->getParent())) != AR);
+ // Otherwise recurse to see if the start value is interesting, and that
+ // the step value is not interesting, since we don't yet know how to
+ // do effective SCEV expansions for addrecs with interesting steps.
+ return isInteresting(AR->getStart(), I, L, SE, LI) &&
+ !isInteresting(AR->getStepRecurrence(*SE), I, L, SE, LI);
}
- // Break down TheAddRec into its component parts.
- SmallVector<const SCEV *, 4> Subexprs;
- CollectSubexprs(TheAddRec, Subexprs, *SE);
-
- // Look for an addrec on the current loop among the parts.
- const SCEV *AddRecStride = 0;
- for (SmallVectorImpl<const SCEV *>::iterator I = Subexprs.begin(),
- E = Subexprs.end(); I != E; ++I) {
- const SCEV *S = *I;
- if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S))
- if (AR->getLoop() == L) {
- *I = AR->getStart();
- AddRecStride = AR->getStepRecurrence(*SE);
- break;
+ // An add is interesting if exactly one of its operands is interesting.
+ if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
+ bool AnyInterestingYet = false;
+ for (SCEVAddExpr::op_iterator OI = Add->op_begin(), OE = Add->op_end();
+ OI != OE; ++OI)
+ if (isInteresting(*OI, I, L, SE, LI)) {
+ if (AnyInterestingYet)
+ return false;
+ AnyInterestingYet = true;
}
- }
- if (!AddRecStride)
- return false;
-
- // Add up everything else into a start value (which may not be
- // loop-invariant).
- const SCEV *AddRecStart = SE->getAddExpr(Subexprs);
-
- // Use getSCEVAtScope to attempt to simplify other loops out of
- // the picture.
- AddRecStart = SE->getSCEVAtScope(AddRecStart, UseLoop);
-
- Start = SE->getAddExpr(Start, AddRecStart);
-
- // If stride is an instruction, make sure it properly dominates the header.
- // Otherwise we could end up with a use before def situation.
- if (!isa<SCEVConstant>(AddRecStride)) {
- BasicBlock *Header = L->getHeader();
- if (!AddRecStride->properlyDominates(Header, DT))
- return false;
-
- DEBUG(dbgs() << "[";
- WriteAsOperand(dbgs(), L->getHeader(), /*PrintType=*/false);
- dbgs() << "] Variable stride: " << *AddRecStride << "\n");
+ return AnyInterestingYet;
}
- Stride = AddRecStride;
- return true;
+ // Nothing else is interesting here.
+ return false;
}
-/// IVUseShouldUsePostIncValue - We have discovered a "User" of an IV expression
-/// and now we need to decide whether the user should use the preinc or post-inc
-/// value. If this user should use the post-inc version of the IV, return true.
-///
-/// Choosing wrong here can break dominance properties (if we choose to use the
-/// post-inc value when we cannot) or it can end up adding extra live-ranges to
-/// the loop, resulting in reg-reg copies (if we use the pre-inc value when we
-/// should use the post-inc value).
-static bool IVUseShouldUsePostIncValue(Instruction *User, Instruction *IV,
- Loop *L, DominatorTree *DT) {
- // If the user is in the loop, use the preinc value.
- if (L->contains(User)) return false;
-
- BasicBlock *LatchBlock = L->getLoopLatch();
- if (!LatchBlock)
- return false;
-
- // Ok, the user is outside of the loop. If it is dominated by the latch
- // block, use the post-inc value.
- if (DT->dominates(LatchBlock, User->getParent()))
- return true;
-
- // There is one case we have to be careful of: PHI nodes. These little guys
- // can live in blocks that are not dominated by the latch block, but (since
- // their uses occur in the predecessor block, not the block the PHI lives in)
- // should still use the post-inc value. Check for this case now.
- PHINode *PN = dyn_cast<PHINode>(User);
- if (!PN) return false; // not a phi, not dominated by latch block.
-
- // Look at all of the uses of IV by the PHI node. If any use corresponds to
- // a block that is not dominated by the latch block, give up and use the
- // preincremented value.
- unsigned NumUses = 0;
- for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
- if (PN->getIncomingValue(i) == IV) {
- ++NumUses;
- if (!DT->dominates(LatchBlock, PN->getIncomingBlock(i)))
+/// Return true if all loop headers that dominate this block are in simplified
+/// form.
+static bool isSimplifiedLoopNest(BasicBlock *BB, const DominatorTree *DT,
+ const LoopInfo *LI,
+ SmallPtrSetImpl<Loop*> &SimpleLoopNests) {
+ Loop *NearestLoop = nullptr;
+ for (DomTreeNode *Rung = DT->getNode(BB);
+ Rung; Rung = Rung->getIDom()) {
+ BasicBlock *DomBB = Rung->getBlock();
+ Loop *DomLoop = LI->getLoopFor(DomBB);
+ if (DomLoop && DomLoop->getHeader() == DomBB) {
+ // If the domtree walk reaches a loop with no preheader, return false.
+ if (!DomLoop->isLoopSimplifyForm())
return false;
+ // If we have already checked this loop nest, stop checking.
+ if (SimpleLoopNests.count(DomLoop))
+ break;
+ // If we have not already checked this loop nest, remember the loop
+ // header nearest to BB. The nearest loop may not contain BB.
+ if (!NearestLoop)
+ NearestLoop = DomLoop;
}
-
- // Okay, all uses of IV by PN are in predecessor blocks that really are
- // dominated by the latch block. Use the post-incremented value.
+ }
+ if (NearestLoop)
+ SimpleLoopNests.insert(NearestLoop);
return true;
}
-/// AddUsersIfInteresting - Inspect the specified instruction. If it is a
+/// AddUsersImpl - Inspect the specified instruction. If it is a
/// reducible SCEV, recursively add its users to the IVUsesByStride set and
/// return true. Otherwise, return false.
-bool IVUsers::AddUsersIfInteresting(Instruction *I) {
+bool IVUsers::AddUsersImpl(Instruction *I,
+ SmallPtrSetImpl<Loop*> &SimpleLoopNests) {
+ const DataLayout &DL = I->getModule()->getDataLayout();
+
+ // Add this IV user to the Processed set before returning false to ensure that
+ // all IV users are members of the set. See IVUsers::isIVUserOrOperand.
+ if (!Processed.insert(I).second)
+ return true; // Instruction already handled.
+
if (!SE->isSCEVable(I->getType()))
return false; // Void and FP expressions cannot be reduced.
+ // IVUsers is used by LSR which assumes that all SCEV expressions are safe to
+ // pass to SCEVExpander. Expressions are not safe to expand if they represent
+ // operations that are not safe to speculate, namely integer division.
+ if (!isa<PHINode>(I) && !isSafeToSpeculativelyExecute(I))
+ return false;
+
// LSR is not APInt clean, do not touch integers bigger than 64-bits.
- if (SE->getTypeSizeInBits(I->getType()) > 64)
+ // Also avoid creating IVs of non-native types. For example, we don't want a
+ // 64-bit IV in 32-bit code just because the loop has one 64-bit cast.
+ uint64_t Width = SE->getTypeSizeInBits(I->getType());
+ if (Width > 64 || !DL.isLegalInteger(Width))
return false;
- if (!Processed.insert(I))
- return true; // Instruction already handled.
+ // Don't attempt to promote ephemeral values to indvars. They will be removed
+ // later anyway.
+ if (EphValues.count(I))
+ return false;
// Get the symbolic expression for this instruction.
const SCEV *ISE = SE->getSCEV(I);
- if (isa<SCEVCouldNotCompute>(ISE)) return false;
-
- // Get the start and stride for this expression.
- Loop *UseLoop = LI->getLoopFor(I->getParent());
- const SCEV *Start = SE->getIntegerSCEV(0, ISE->getType());
- const SCEV *Stride = Start;
- if (!getSCEVStartAndStride(ISE, L, UseLoop, Start, Stride, SE, DT))
- return false; // Non-reducible symbolic expression, bail out.
-
- // Keep things simple. Don't touch loop-variant strides.
- if (!Stride->isLoopInvariant(L) && L->contains(I))
+ // If we've come to an uninteresting expression, stop the traversal and
+ // call this a user.
+ if (!isInteresting(ISE, I, L, SE, LI))
return false;
SmallPtrSet<Instruction *, 4> UniqueUsers;
- for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
- UI != E; ++UI) {
- Instruction *User = cast<Instruction>(*UI);
- if (!UniqueUsers.insert(User))
+ for (Use &U : I->uses()) {
+ Instruction *User = cast<Instruction>(U.getUser());
+ if (!UniqueUsers.insert(User).second)
continue;
// Do not infinitely recurse on PHI nodes.
if (isa<PHINode>(User) && Processed.count(User))
continue;
+ // Only consider IVUsers that are dominated by simplified loop
+ // headers. Otherwise, SCEVExpander will crash.
+ BasicBlock *UseBB = User->getParent();
+ // A phi's use is live out of its predecessor block.
+ if (PHINode *PHI = dyn_cast<PHINode>(User)) {
+ unsigned OperandNo = U.getOperandNo();
+ unsigned ValNo = PHINode::getIncomingValueNumForOperand(OperandNo);
+ UseBB = PHI->getIncomingBlock(ValNo);
+ }
+ if (!isSimplifiedLoopNest(UseBB, DT, LI, SimpleLoopNests))
+ return false;
+
// Descend recursively, but not into PHI nodes outside the current loop.
// It's important to see the entire expression outside the loop to get
// choices that depend on addressing mode use right, although we won't
- // consider references ouside the loop in all cases.
+ // consider references outside the loop in all cases.
// If User is already in Processed, we don't want to recurse into it again,
// but do want to record a second reference in the same instruction.
bool AddUserToIVUsers = false;
if (LI->getLoopFor(User->getParent()) != L) {
if (isa<PHINode>(User) || Processed.count(User) ||
- !AddUsersIfInteresting(User)) {
+ !AddUsersImpl(User, SimpleLoopNests)) {
DEBUG(dbgs() << "FOUND USER in other loop: " << *User << '\n'
<< " OF SCEV: " << *ISE << '\n');
AddUserToIVUsers = true;
}
- } else if (Processed.count(User) ||
- !AddUsersIfInteresting(User)) {
+ } else if (Processed.count(User) || !AddUsersImpl(User, SimpleLoopNests)) {
DEBUG(dbgs() << "FOUND USER: " << *User << '\n'
<< " OF SCEV: " << *ISE << '\n');
AddUserToIVUsers = true;
}
if (AddUserToIVUsers) {
- // Okay, we found a user that we cannot reduce. Analyze the instruction
- // and decide what to do with it. If we are a use inside of the loop, use
- // the value before incrementation, otherwise use it after incrementation.
- if (IVUseShouldUsePostIncValue(User, I, L, DT)) {
- // The value used will be incremented by the stride more than we are
- // expecting, so subtract this off.
- const SCEV *NewStart = SE->getMinusSCEV(Start, Stride);
- IVUses.push_back(new IVStrideUse(this, Stride, NewStart, User, I));
- IVUses.back().setIsUseOfPostIncrementedValue(true);
- DEBUG(dbgs() << " USING POSTINC SCEV, START=" << *NewStart<< "\n");
- } else {
- IVUses.push_back(new IVStrideUse(this, Stride, Start, User, I));
+ // Okay, we found a user that we cannot reduce.
+ IVStrideUse &NewUse = AddUser(User, I);
+ // Autodetect the post-inc loop set, populating NewUse.PostIncLoops.
+ // The regular return value here is discarded; instead of recording
+ // it, we just recompute it when we need it.
+ const SCEV *OriginalISE = ISE;
+ ISE = TransformForPostIncUse(NormalizeAutodetect,
+ ISE, User, I,
+ NewUse.PostIncLoops,
+ *SE, *DT);
+
+ // PostIncNormalization effectively simplifies the expression under
+ // pre-increment assumptions. Those assumptions (no wrapping) might not
+ // hold for the post-inc value. Catch such cases by making sure the
+ // transformation is invertible.
+ if (OriginalISE != ISE) {
+ const SCEV *DenormalizedISE =
+ TransformForPostIncUse(Denormalize, ISE, User, I,
+ NewUse.PostIncLoops, *SE, *DT);
+
+ // If we normalized the expression, but denormalization doesn't give the
+ // original one, discard this user.
+ if (OriginalISE != DenormalizedISE) {
+ DEBUG(dbgs() << " DISCARDING (NORMALIZATION ISN'T INVERTIBLE): "
+ << *ISE << '\n');
+ IVUses.pop_back();
+ return false;
+ }
}
+ DEBUG(if (SE->getSCEV(I) != ISE)
+ dbgs() << " NORMALIZED TO: " << *ISE << '\n');
}
}
return true;
}
-IVStrideUse &IVUsers::AddUser(const SCEV *Stride, const SCEV *Offset,
- Instruction *User, Value *Operand) {
- IVUses.push_back(new IVStrideUse(this, Stride, Offset, User, Operand));
+bool IVUsers::AddUsersIfInteresting(Instruction *I) {
+ // SCEVExpander can only handle users that are dominated by simplified loop
+ // entries. Keep track of all loops that are only dominated by other simple
+ // loops so we don't traverse the domtree for each user.
+ SmallPtrSet<Loop*,16> SimpleLoopNests;
+
+ return AddUsersImpl(I, SimpleLoopNests);
+}
+
+IVStrideUse &IVUsers::AddUser(Instruction *User, Value *Operand) {
+ IVUses.push_back(new IVStrideUse(this, User, Operand));
return IVUses.back();
}
IVUsers::IVUsers()
- : LoopPass(&ID) {
+ : LoopPass(ID) {
+ initializeIVUsersPass(*PassRegistry::getPassRegistry());
}
void IVUsers::getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequired<LoopInfo>();
- AU.addRequired<DominatorTree>();
- AU.addRequired<ScalarEvolution>();
+ AU.addRequired<AssumptionCacheTracker>();
+ AU.addRequired<LoopInfoWrapperPass>();
+ AU.addRequired<DominatorTreeWrapperPass>();
+ AU.addRequired<ScalarEvolutionWrapperPass>();
AU.setPreservesAll();
}
bool IVUsers::runOnLoop(Loop *l, LPPassManager &LPM) {
L = l;
- LI = &getAnalysis<LoopInfo>();
- DT = &getAnalysis<DominatorTree>();
- SE = &getAnalysis<ScalarEvolution>();
+ AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(
+ *L->getHeader()->getParent());
+ LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+ DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+ SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
+
+ // Collect ephemeral values so that AddUsersIfInteresting skips them.
+ EphValues.clear();
+ CodeMetrics::collectEphemeralValues(L, AC, EphValues);
// Find all uses of induction variables in this loop, and categorize
// them by stride. Start by finding all of the PHI nodes in the header for
// this loop. If they are induction variables, inspect their uses.
for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I)
- AddUsersIfInteresting(I);
+ (void)AddUsersIfInteresting(&*I);
return false;
}
-/// getReplacementExpr - Return a SCEV expression which computes the
-/// value of the OperandValToReplace of the given IVStrideUse.
-const SCEV *IVUsers::getReplacementExpr(const IVStrideUse &U) const {
- // Start with zero.
- const SCEV *RetVal = SE->getIntegerSCEV(0, U.getStride()->getType());
- // Create the basic add recurrence.
- RetVal = SE->getAddRecExpr(RetVal, U.getStride(), L);
- // Add the offset in a separate step, because it may be loop-variant.
- RetVal = SE->getAddExpr(RetVal, U.getOffset());
- // For uses of post-incremented values, add an extra stride to compute
- // the actual replacement value.
- if (U.isUseOfPostIncrementedValue())
- RetVal = SE->getAddExpr(RetVal, U.getStride());
- return RetVal;
-}
-
-/// getCanonicalExpr - Return a SCEV expression which computes the
-/// value of the SCEV of the given IVStrideUse, ignoring the
-/// isUseOfPostIncrementedValue flag.
-const SCEV *IVUsers::getCanonicalExpr(const IVStrideUse &U) const {
- // Start with zero.
- const SCEV *RetVal = SE->getIntegerSCEV(0, U.getStride()->getType());
- // Create the basic add recurrence.
- RetVal = SE->getAddRecExpr(RetVal, U.getStride(), L);
- // Add the offset in a separate step, because it may be loop-variant.
- RetVal = SE->getAddExpr(RetVal, U.getOffset());
- return RetVal;
-}
-
void IVUsers::print(raw_ostream &OS, const Module *M) const {
OS << "IV Users for loop ";
- WriteAsOperand(OS, L->getHeader(), false);
+ L->getHeader()->printAsOperand(OS, false);
if (SE->hasLoopInvariantBackedgeTakenCount(L)) {
OS << " with backedge-taken count "
<< *SE->getBackedgeTakenCount(L);
}
OS << ":\n";
- // Use a defualt AssemblyAnnotationWriter to suppress the default info
- // comments, which aren't relevant here.
- AssemblyAnnotationWriter Annotator;
for (ilist<IVStrideUse>::const_iterator UI = IVUses.begin(),
E = IVUses.end(); UI != E; ++UI) {
OS << " ";
- WriteAsOperand(OS, UI->getOperandValToReplace(), false);
- OS << " = "
- << *getReplacementExpr(*UI);
- if (UI->isUseOfPostIncrementedValue())
- OS << " (post-inc)";
+ UI->getOperandValToReplace()->printAsOperand(OS, false);
+ OS << " = " << *getReplacementExpr(*UI);
+ for (PostIncLoopSet::const_iterator
+ I = UI->PostIncLoops.begin(),
+ E = UI->PostIncLoops.end(); I != E; ++I) {
+ OS << " (post-inc with loop ";
+ (*I)->getHeader()->printAsOperand(OS, false);
+ OS << ")";
+ }
OS << " in ";
- UI->getUser()->print(OS, &Annotator);
+ if (UI->getUser())
+ UI->getUser()->print(OS);
+ else
+ OS << "Printing <null> User";
OS << '\n';
}
}
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void IVUsers::dump() const {
print(dbgs());
}
+#endif
void IVUsers::releaseMemory() {
Processed.clear();
IVUses.clear();
}
+/// getReplacementExpr - Return a SCEV expression which computes the
+/// value of the OperandValToReplace.
+const SCEV *IVUsers::getReplacementExpr(const IVStrideUse &IU) const {
+ return SE->getSCEV(IU.getOperandValToReplace());
+}
+
+/// getExpr - Return the expression for the use.
+const SCEV *IVUsers::getExpr(const IVStrideUse &IU) const {
+ return
+ TransformForPostIncUse(Normalize, getReplacementExpr(IU),
+ IU.getUser(), IU.getOperandValToReplace(),
+ const_cast<PostIncLoopSet &>(IU.getPostIncLoops()),
+ *SE, *DT);
+}
+
+static const SCEVAddRecExpr *findAddRecForLoop(const SCEV *S, const Loop *L) {
+ if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
+ if (AR->getLoop() == L)
+ return AR;
+ return findAddRecForLoop(AR->getStart(), L);
+ }
+
+ if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
+ for (SCEVAddExpr::op_iterator I = Add->op_begin(), E = Add->op_end();
+ I != E; ++I)
+ if (const SCEVAddRecExpr *AR = findAddRecForLoop(*I, L))
+ return AR;
+ return nullptr;
+ }
+
+ return nullptr;
+}
+
+const SCEV *IVUsers::getStride(const IVStrideUse &IU, const Loop *L) const {
+ if (const SCEVAddRecExpr *AR = findAddRecForLoop(getExpr(IU), L))
+ return AR->getStepRecurrence(*SE);
+ return nullptr;
+}
+
+void IVStrideUse::transformToPostInc(const Loop *L) {
+ PostIncLoops.insert(L);
+}
+
void IVStrideUse::deleted() {
// Remove this user from the list.
+ Parent->Processed.erase(this->getUser());
Parent->IVUses.erase(this);
// this now dangles!
}
projects / oota-llvm.git / blobdiff