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Make IVUsers iterative instead of recursive.
This has the side effect of reversing the order of most of IVUser's results. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112442 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -27,6 +27,7 @@ class Value;
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class IVUsers;
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class ScalarEvolution;
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class SCEV;
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class SCEVAddRecExpr;
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class IVUsers;
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/// IVStrideUse - Keep track of one use of a strided induction variable.
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@ -122,7 +123,7 @@ class IVUsers : public LoopPass {
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LoopInfo *LI;
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DominatorTree *DT;
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ScalarEvolution *SE;
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SmallPtrSet<Instruction*,16> Processed;
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SmallPtrSet<Instruction *, 16> Processed;
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/// IVUses - A list of all tracked IV uses of induction variable expressions
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/// we are interested in.
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@ -134,14 +135,16 @@ class IVUsers : public LoopPass {
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virtual void releaseMemory();
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const SCEVAddRecExpr *findInterestingAddRec(const SCEV *S) const;
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bool isInterestingUser(const Instruction *User) const;
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public:
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static char ID; // Pass ID, replacement for typeid
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IVUsers();
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/// AddUsersIfInteresting - Inspect the specified Instruction. If it is a
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/// reducible SCEV, recursively add its users to the IVUsesByStride set and
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/// return true. Otherwise, return false.
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bool AddUsersIfInteresting(Instruction *I);
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/// AddUsersIfInteresting - Inspect the def-use graph starting at the
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/// specified Instruction and add IVUsers.
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void AddUsersIfInteresting(Instruction *I);
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IVStrideUse &AddUser(Instruction *User, Value *Operand);
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@ -35,112 +35,123 @@ Pass *llvm::createIVUsersPass() {
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return new IVUsers();
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}
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/// isInteresting - Test whether the given expression is "interesting" when
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/// used by the given expression, within the context of analyzing the
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/// given loop.
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static bool isInteresting(const SCEV *S, const Instruction *I, const Loop *L,
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ScalarEvolution *SE) {
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/// findInterestingAddRec - Test whether the given expression is interesting.
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/// Return the addrec with the current loop which makes it interesting, or
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/// null if it is not interesting.
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const SCEVAddRecExpr *IVUsers::findInterestingAddRec(const SCEV *S) const {
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// An addrec is interesting if it's affine or if it has an interesting start.
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if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
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// Keep things simple. Don't touch loop-variant strides.
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if (AR->getLoop() == L)
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return AR->isAffine() || !L->contains(I);
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// Otherwise recurse to see if the start value is interesting, and that
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// the step value is not interesting, since we don't yet know how to
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// do effective SCEV expansions for addrecs with interesting steps.
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return isInteresting(AR->getStart(), I, L, SE) &&
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!isInteresting(AR->getStepRecurrence(*SE), I, L, SE);
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return AR;
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// We don't yet know how to do effective SCEV expansions for addrecs
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// with interesting steps.
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if (findInterestingAddRec(AR->getStepRecurrence(*SE)))
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return 0;
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// Otherwise recurse to see if the start value is interesting.
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return findInterestingAddRec(AR->getStart());
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}
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// An add is interesting if exactly one of its operands is interesting.
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if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
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bool AnyInterestingYet = false;
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for (SCEVAddExpr::op_iterator OI = Add->op_begin(), OE = Add->op_end();
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OI != OE; ++OI)
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if (isInteresting(*OI, I, L, SE)) {
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if (AnyInterestingYet)
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return false;
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AnyInterestingYet = true;
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}
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return AnyInterestingYet;
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if (const SCEVAddRecExpr *AR = findInterestingAddRec(*OI))
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return AR;
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return 0;
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}
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// Nothing else is interesting here.
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return false;
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return 0;
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}
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bool IVUsers::isInterestingUser(const Instruction *User) const {
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// Void and FP expressions cannot be reduced.
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if (!SE->isSCEVable(User->getType()))
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return false;
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// LSR is not APInt clean, do not touch integers bigger than 64-bits.
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if (SE->getTypeSizeInBits(User->getType()) > 64)
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return false;
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// Don't descend into PHI nodes outside the current loop.
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if (LI->getLoopFor(User->getParent()) != L &&
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isa<PHINode>(User))
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return false;
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// Otherwise, it may be interesting.
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return true;
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}
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/// AddUsersIfInteresting - Inspect the specified instruction. If it is a
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/// reducible SCEV, recursively add its users to the IVUsesByStride set and
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/// return true. Otherwise, return false.
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bool IVUsers::AddUsersIfInteresting(Instruction *I) {
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if (!SE->isSCEVable(I->getType()))
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return false; // Void and FP expressions cannot be reduced.
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// LSR is not APInt clean, do not touch integers bigger than 64-bits.
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if (SE->getTypeSizeInBits(I->getType()) > 64)
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return false;
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void IVUsers::AddUsersIfInteresting(Instruction *I) {
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// Stop if we've seen this before.
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if (!Processed.insert(I))
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return true; // Instruction already handled.
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return;
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// Get the symbolic expression for this instruction.
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const SCEV *ISE = SE->getSCEV(I);
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// If this PHI node is not SCEVable, ignore it.
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if (!SE->isSCEVable(I->getType()))
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return;
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// If we've come to an uninteresting expression, stop the traversal and
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// call this a user.
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if (!isInteresting(ISE, I, L, SE))
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return false;
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// If this PHI node is not an addrec for this loop, ignore it.
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const SCEVAddRecExpr *Expr = findInterestingAddRec(SE->getSCEV(I));
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if (!Expr)
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return;
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SmallPtrSet<Instruction *, 4> UniqueUsers;
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for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
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UI != E; ++UI) {
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Instruction *User = cast<Instruction>(*UI);
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if (!UniqueUsers.insert(User))
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continue;
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// Walk the def-use graph.
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SmallVector<std::pair<Instruction *, const SCEVAddRecExpr *>, 16> Worklist;
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Worklist.push_back(std::make_pair(I, Expr));
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do {
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std::pair<Instruction *, const SCEVAddRecExpr *> P =
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Worklist.pop_back_val();
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Instruction *Op = P.first;
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const SCEVAddRecExpr *OpAR = P.second;
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// Do not infinitely recurse on PHI nodes.
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if (isa<PHINode>(User) && Processed.count(User))
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continue;
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// Visit Op's users.
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SmallPtrSet<Instruction *, 8> VisitedUsers;
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for (Value::use_iterator UI = Op->use_begin(), E = Op->use_end();
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UI != E; ++UI) {
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// Don't visit any individual user more than once.
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Instruction *User = cast<Instruction>(*UI);
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if (!VisitedUsers.insert(User))
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continue;
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// Descend recursively, but not into PHI nodes outside the current loop.
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// It's important to see the entire expression outside the loop to get
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// choices that depend on addressing mode use right, although we won't
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// consider references outside the loop in all cases.
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// If User is already in Processed, we don't want to recurse into it again,
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// but do want to record a second reference in the same instruction.
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bool AddUserToIVUsers = false;
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if (LI->getLoopFor(User->getParent()) != L) {
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if (isa<PHINode>(User) || Processed.count(User) ||
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!AddUsersIfInteresting(User)) {
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DEBUG(dbgs() << "FOUND USER in other loop: " << *User << '\n'
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<< " OF SCEV: " << *ISE << '\n');
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AddUserToIVUsers = true;
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// If it's an affine addrec (which we can pretty safely re-expand) inside
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// the loop, or a potentially non-affine addrec outside the loop (which
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// we can evaluate outside of the loop), follow it.
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if (OpAR->isAffine() || !L->contains(User)) {
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if (isInterestingUser(User)) {
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const SCEV *UserExpr = SE->getSCEV(User);
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if (const SCEVAddRecExpr *AR = findInterestingAddRec(UserExpr)) {
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// Interesting. Keep searching.
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if (Processed.insert(User))
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Worklist.push_back(std::make_pair(User, AR));
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continue;
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}
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}
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}
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} else if (Processed.count(User) ||
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!AddUsersIfInteresting(User)) {
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DEBUG(dbgs() << "FOUND USER: " << *User << '\n'
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<< " OF SCEV: " << *ISE << '\n');
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AddUserToIVUsers = true;
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}
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if (AddUserToIVUsers) {
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// Okay, we found a user that we cannot reduce.
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IVUses.push_back(new IVStrideUse(this, User, I));
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IVStrideUse &NewUse = IVUses.back();
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// Transform the expression into a normalized form.
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ISE = TransformForPostIncUse(NormalizeAutodetect,
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ISE, User, I,
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NewUse.PostIncLoops,
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*SE, *DT);
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DEBUG(dbgs() << " NORMALIZED TO: " << *ISE << '\n');
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// Otherwise, this is the point where the def-use chain
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// becomes uninteresting. Call it an IV User.
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AddUser(User, Op);
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}
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}
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return true;
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} while (!Worklist.empty());
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}
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IVStrideUse &IVUsers::AddUser(Instruction *User, Value *Operand) {
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IVUses.push_back(new IVStrideUse(this, User, Operand));
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return IVUses.back();
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IVStrideUse &NewUse = IVUses.back();
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// Auto-detect and remember post-inc loops for this expression.
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const SCEV *S = SE->getSCEV(Operand);
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(void)TransformForPostIncUse(NormalizeAutodetect,
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S, User, Operand,
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NewUse.PostIncLoops,
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*SE, *DT);
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return NewUse;
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}
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IVUsers::IVUsers()
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@ -165,7 +176,7 @@ bool IVUsers::runOnLoop(Loop *l, LPPassManager &LPM) {
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// them by stride. Start by finding all of the PHI nodes in the header for
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// this loop. If they are induction variables, inspect their uses.
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for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I)
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(void)AddUsersIfInteresting(I);
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AddUsersIfInteresting(I);
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return false;
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}
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@ -452,9 +452,9 @@ bb5: ; preds = %bb3, %entry
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; CHECK-NEXT: addss %xmm{{.*}}, %xmm{{.*}}
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; CHECK-NEXT: mulss (%r{{[^,]*}}), %xmm{{.*}}
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; CHECK-NEXT: movss %xmm{{.*}}, (%r{{[^,]*}})
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; CHECK-NEXT: addq $4, %r{{.*}}
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; CHECK-NEXT: decq %r{{.*}}
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; CHECK-NEXT: addq $4, %r{{.*}}
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; CHECK-NEXT: addq $4, %r{{.*}}
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; CHECK-NEXT: movaps %xmm{{.*}}, %xmm{{.*}}
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; CHECK-NEXT: BB10_2:
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; CHECK-NEXT: testq %r{{.*}}, %r{{.*}}
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