//
//===----------------------------------------------------------------------===//
//
+// This transformation analyzes and transforms the induction variables (and
+// computations derived from them) into forms suitable for efficient execution
+// on the target.
+//
// This pass performs a strength reduction on array references inside loops that
-// have as one or more of their components the loop induction variable.
+// have as one or more of their components the loop induction variable, it
+// rewrites expressions to take advantage of scaled-index addressing modes
+// available on the target, and it performs a variety of other optimizations
+// related to loop induction variables.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/AddrModeMatcher.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/Debug.h"
-#include "llvm/Support/Compiler.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ValueHandle.h"
+#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetLowering.h"
#include <algorithm>
using namespace llvm;
/// IVInfo - This structure keeps track of one IV expression inserted during
/// StrengthReduceStridedIVUsers. It contains the stride, the common base, as
/// well as the PHI node and increment value created for rewrite.
- struct VISIBILITY_HIDDEN IVExpr {
- SCEVHandle Stride;
- SCEVHandle Base;
+ struct IVExpr {
+ const SCEV *Stride;
+ const SCEV *Base;
PHINode *PHI;
- IVExpr(const SCEVHandle &stride, const SCEVHandle &base, PHINode *phi)
+ IVExpr(const SCEV *const stride, const SCEV *const base, PHINode *phi)
: Stride(stride), Base(base), PHI(phi) {}
};
/// IVsOfOneStride - This structure keeps track of all IV expression inserted
/// during StrengthReduceStridedIVUsers for a particular stride of the IV.
- struct VISIBILITY_HIDDEN IVsOfOneStride {
+ struct IVsOfOneStride {
std::vector<IVExpr> IVs;
- void addIV(const SCEVHandle &Stride, const SCEVHandle &Base, PHINode *PHI) {
+ void addIV(const SCEV *const Stride, const SCEV *const Base, PHINode *PHI) {
IVs.push_back(IVExpr(Stride, Base, PHI));
}
};
- class VISIBILITY_HIDDEN LoopStrengthReduce : public LoopPass {
+ class LoopStrengthReduce : public LoopPass {
IVUsers *IU;
LoopInfo *LI;
DominatorTree *DT;
/// IVsByStride - Keep track of all IVs that have been inserted for a
/// particular stride.
- std::map<SCEVHandle, IVsOfOneStride> IVsByStride;
+ std::map<const SCEV *, IVsOfOneStride> IVsByStride;
/// StrideNoReuse - Keep track of all the strides whose ivs cannot be
/// reused (nor should they be rewritten to reuse other strides).
- SmallSet<SCEVHandle, 4> StrideNoReuse;
+ SmallSet<const SCEV *, 4> StrideNoReuse;
/// DeadInsts - Keep track of instructions we may have made dead, so that
/// we can remove them after we are done working.
private:
ICmpInst *ChangeCompareStride(Loop *L, ICmpInst *Cond,
IVStrideUse* &CondUse,
- const SCEVHandle* &CondStride);
+ const SCEV *const * &CondStride);
void OptimizeIndvars(Loop *L);
void OptimizeLoopCountIV(Loop *L);
/// inside the loop then try to eliminate the cast opeation.
void OptimizeShadowIV(Loop *L);
- /// OptimizeSMax - Rewrite the loop's terminating condition
- /// if it uses an smax computation.
- ICmpInst *OptimizeSMax(Loop *L, ICmpInst *Cond,
- IVStrideUse* &CondUse);
+ /// OptimizeMax - Rewrite the loop's terminating condition
+ /// if it uses a max computation.
+ ICmpInst *OptimizeMax(Loop *L, ICmpInst *Cond,
+ IVStrideUse* &CondUse);
bool FindIVUserForCond(ICmpInst *Cond, IVStrideUse *&CondUse,
- const SCEVHandle *&CondStride);
+ const SCEV *const * &CondStride);
bool RequiresTypeConversion(const Type *Ty, const Type *NewTy);
- SCEVHandle CheckForIVReuse(bool, bool, bool, const SCEVHandle&,
+ const SCEV *CheckForIVReuse(bool, bool, bool, const SCEV *const&,
IVExpr&, const Type*,
const std::vector<BasedUser>& UsersToProcess);
bool ValidScale(bool, int64_t,
const std::vector<BasedUser>& UsersToProcess);
bool ValidOffset(bool, int64_t, int64_t,
const std::vector<BasedUser>& UsersToProcess);
- SCEVHandle CollectIVUsers(const SCEVHandle &Stride,
+ const SCEV *CollectIVUsers(const SCEV *const &Stride,
IVUsersOfOneStride &Uses,
Loop *L,
bool &AllUsesAreAddresses,
const std::vector<BasedUser> &UsersToProcess,
const Loop *L,
bool AllUsesAreAddresses,
- SCEVHandle Stride);
+ const SCEV *Stride);
void PrepareToStrengthReduceFully(
std::vector<BasedUser> &UsersToProcess,
- SCEVHandle Stride,
- SCEVHandle CommonExprs,
+ const SCEV *Stride,
+ const SCEV *CommonExprs,
const Loop *L,
SCEVExpander &PreheaderRewriter);
void PrepareToStrengthReduceFromSmallerStride(
Instruction *PreInsertPt);
void PrepareToStrengthReduceWithNewPhi(
std::vector<BasedUser> &UsersToProcess,
- SCEVHandle Stride,
- SCEVHandle CommonExprs,
+ const SCEV *Stride,
+ const SCEV *CommonExprs,
Value *CommonBaseV,
Instruction *IVIncInsertPt,
const Loop *L,
SCEVExpander &PreheaderRewriter);
- void StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
+ void StrengthReduceStridedIVUsers(const SCEV *const &Stride,
IVUsersOfOneStride &Uses,
Loop *L);
void DeleteTriviallyDeadInstructions();
/// containsAddRecFromDifferentLoop - Determine whether expression S involves a
/// subexpression that is an AddRec from a loop other than L. An outer loop
/// of L is OK, but not an inner loop nor a disjoint loop.
-static bool containsAddRecFromDifferentLoop(SCEVHandle S, Loop *L) {
+static bool containsAddRecFromDifferentLoop(const SCEV *S, Loop *L) {
// This is very common, put it first.
if (isa<SCEVConstant>(S))
return false;
if (newLoop == L)
return false;
// if newLoop is an outer loop of L, this is OK.
- if (!LoopInfoBase<BasicBlock>::isNotAlreadyContainedIn(L, newLoop))
+ if (!LoopInfo::isNotAlreadyContainedIn(L, newLoop))
return false;
}
return true;
/// this use. As the use is processed, information gets moved from this
/// field to the Imm field (below). BasedUser values are sorted by this
/// field.
- SCEVHandle Base;
+ const SCEV *Base;
/// Inst - The instruction using the induction variable.
Instruction *Inst;
/// EmittedBase.
Value *OperandValToReplace;
- /// isSigned - The stride (and thus also the Base) of this use may be in
- /// a narrower type than the use itself (OperandValToReplace->getType()).
- /// When this is the case, the isSigned field indicates whether the
- /// IV expression should be signed-extended instead of zero-extended to
- /// fit the type of the use.
- bool isSigned;
-
/// Imm - The immediate value that should be added to the base immediately
/// before Inst, because it will be folded into the imm field of the
/// instruction. This is also sometimes used for loop-variant values that
/// must be added inside the loop.
- SCEVHandle Imm;
+ const SCEV *Imm;
/// Phi - The induction variable that performs the striding that
/// should be used for this user.
BasedUser(IVStrideUse &IVSU, ScalarEvolution *se)
: SE(se), Base(IVSU.getOffset()), Inst(IVSU.getUser()),
OperandValToReplace(IVSU.getOperandValToReplace()),
- isSigned(IVSU.isSigned()),
Imm(SE->getIntegerSCEV(0, Base->getType())),
isUseOfPostIncrementedValue(IVSU.isUseOfPostIncrementedValue()) {}
// Once we rewrite the code to insert the new IVs we want, update the
// operands of Inst to use the new expression 'NewBase', with 'Imm' added
// to it.
- void RewriteInstructionToUseNewBase(const SCEVHandle &NewBase,
+ void RewriteInstructionToUseNewBase(const SCEV *const &NewBase,
Instruction *InsertPt,
SCEVExpander &Rewriter, Loop *L, Pass *P,
LoopInfo &LI,
SmallVectorImpl<WeakVH> &DeadInsts);
- Value *InsertCodeForBaseAtPosition(const SCEVHandle &NewBase,
+ Value *InsertCodeForBaseAtPosition(const SCEV *const &NewBase,
const Type *Ty,
SCEVExpander &Rewriter,
Instruction *IP, Loop *L,
}
void BasedUser::dump() const {
- cerr << " Base=" << *Base;
- cerr << " Imm=" << *Imm;
- cerr << " Inst: " << *Inst;
+ errs() << " Base=" << *Base;
+ errs() << " Imm=" << *Imm;
+ errs() << " Inst: " << *Inst;
}
-Value *BasedUser::InsertCodeForBaseAtPosition(const SCEVHandle &NewBase,
+Value *BasedUser::InsertCodeForBaseAtPosition(const SCEV *const &NewBase,
const Type *Ty,
SCEVExpander &Rewriter,
Instruction *IP, Loop *L,
Value *Base = Rewriter.expandCodeFor(NewBase, 0, BaseInsertPt);
- SCEVHandle NewValSCEV = SE->getUnknown(Base);
-
- // If there is no immediate value, skip the next part.
- if (!Imm->isZero()) {
- // If we are inserting the base and imm values in the same block, make sure
- // to adjust the IP position if insertion reused a result.
- if (IP == BaseInsertPt)
- IP = Rewriter.getInsertionPoint();
+ const SCEV *NewValSCEV = SE->getUnknown(Base);
- // Always emit the immediate (if non-zero) into the same block as the user.
- NewValSCEV = SE->getAddExpr(NewValSCEV, Imm);
- }
-
- if (isSigned)
- NewValSCEV = SE->getTruncateOrSignExtend(NewValSCEV, Ty);
- else
- NewValSCEV = SE->getTruncateOrZeroExtend(NewValSCEV, Ty);
+ // Always emit the immediate into the same block as the user.
+ NewValSCEV = SE->getAddExpr(NewValSCEV, Imm);
return Rewriter.expandCodeFor(NewValSCEV, Ty, IP);
}
// value of NewBase in the case that it's a diffferent instruction from
// the PHI that NewBase is computed from, or null otherwise.
//
-void BasedUser::RewriteInstructionToUseNewBase(const SCEVHandle &NewBase,
+void BasedUser::RewriteInstructionToUseNewBase(const SCEV *const &NewBase,
Instruction *NewBasePt,
SCEVExpander &Rewriter, Loop *L, Pass *P,
LoopInfo &LI,
// Replace the use of the operand Value with the new Phi we just created.
Inst->replaceUsesOfWith(OperandValToReplace, NewVal);
- DOUT << " Replacing with ";
- DEBUG(WriteAsOperand(*DOUT, NewVal, /*PrintType=*/false));
- DOUT << ", which has value " << *NewBase << " plus IMM " << *Imm << "\n";
+ DEBUG(errs() << " Replacing with ");
+ DEBUG(WriteAsOperand(errs(), NewVal, /*PrintType=*/false));
+ DEBUG(errs() << ", which has value " << *NewBase << " plus IMM "
+ << *Imm << "\n");
return;
}
// loop because multiple copies sometimes do useful sinking of code in
// that case(?).
Instruction *OldLoc = dyn_cast<Instruction>(OperandValToReplace);
+ BasicBlock *PHIPred = PN->getIncomingBlock(i);
if (L->contains(OldLoc->getParent())) {
// If this is a critical edge, split the edge so that we do not insert
// the code on all predecessor/successor paths. We do this unless this
// is the canonical backedge for this loop, as this can make some
// inserted code be in an illegal position.
- BasicBlock *PHIPred = PN->getIncomingBlock(i);
if (e != 1 && PHIPred->getTerminator()->getNumSuccessors() > 1 &&
(PN->getParent() != L->getHeader() || !L->contains(PHIPred))) {
// First step, split the critical edge.
- SplitCriticalEdge(PHIPred, PN->getParent(), P, false);
+ BasicBlock *NewBB = SplitCriticalEdge(PHIPred, PN->getParent(),
+ P, false);
// Next step: move the basic block. In particular, if the PHI node
// is outside of the loop, and PredTI is in the loop, we want to
// move the block to be immediately before the PHI block, not
// immediately after PredTI.
- if (L->contains(PHIPred) && !L->contains(PN->getParent())) {
- BasicBlock *NewBB = PN->getIncomingBlock(i);
+ if (L->contains(PHIPred) && !L->contains(PN->getParent()))
NewBB->moveBefore(PN->getParent());
- }
// Splitting the edge can reduce the number of PHI entries we have.
e = PN->getNumIncomingValues();
+ PHIPred = NewBB;
+ i = PN->getBasicBlockIndex(PHIPred);
}
}
- Value *&Code = InsertedCode[PN->getIncomingBlock(i)];
+ Value *&Code = InsertedCode[PHIPred];
if (!Code) {
// Insert the code into the end of the predecessor block.
Instruction *InsertPt = (L->contains(OldLoc->getParent())) ?
- PN->getIncomingBlock(i)->getTerminator() :
+ PHIPred->getTerminator() :
OldLoc->getParent()->getTerminator();
Code = InsertCodeForBaseAtPosition(NewBase, PN->getType(),
Rewriter, InsertPt, L, LI);
- DOUT << " Changing PHI use to ";
- DEBUG(WriteAsOperand(*DOUT, Code, /*PrintType=*/false));
- DOUT << ", which has value " << *NewBase << " plus IMM " << *Imm << "\n";
+ DEBUG(errs() << " Changing PHI use to ");
+ DEBUG(WriteAsOperand(errs(), Code, /*PrintType=*/false));
+ DEBUG(errs() << ", which has value " << *NewBase << " plus IMM "
+ << *Imm << "\n");
}
// Replace the use of the operand Value with the new Phi we just created.
/// fitsInAddressMode - Return true if V can be subsumed within an addressing
/// mode, and does not need to be put in a register first.
-static bool fitsInAddressMode(const SCEVHandle &V, const Type *AccessTy,
+static bool fitsInAddressMode(const SCEV *const &V, const Type *AccessTy,
const TargetLowering *TLI, bool HasBaseReg) {
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(V)) {
int64_t VC = SC->getValue()->getSExtValue();
/// MoveLoopVariantsToImmediateField - Move any subexpressions from Val that are
/// loop varying to the Imm operand.
-static void MoveLoopVariantsToImmediateField(SCEVHandle &Val, SCEVHandle &Imm,
+static void MoveLoopVariantsToImmediateField(const SCEV *&Val, const SCEV *&Imm,
Loop *L, ScalarEvolution *SE) {
if (Val->isLoopInvariant(L)) return; // Nothing to do.
if (const SCEVAddExpr *SAE = dyn_cast<SCEVAddExpr>(Val)) {
- std::vector<SCEVHandle> NewOps;
+ SmallVector<const SCEV *, 4> NewOps;
NewOps.reserve(SAE->getNumOperands());
for (unsigned i = 0; i != SAE->getNumOperands(); ++i)
Val = SE->getAddExpr(NewOps);
} else if (const SCEVAddRecExpr *SARE = dyn_cast<SCEVAddRecExpr>(Val)) {
// Try to pull immediates out of the start value of nested addrec's.
- SCEVHandle Start = SARE->getStart();
+ const SCEV *Start = SARE->getStart();
MoveLoopVariantsToImmediateField(Start, Imm, L, SE);
- std::vector<SCEVHandle> Ops(SARE->op_begin(), SARE->op_end());
+ SmallVector<const SCEV *, 4> Ops(SARE->op_begin(), SARE->op_end());
Ops[0] = Start;
Val = SE->getAddRecExpr(Ops, SARE->getLoop());
} else {
/// Accumulate these immediate values into the Imm value.
static void MoveImmediateValues(const TargetLowering *TLI,
const Type *AccessTy,
- SCEVHandle &Val, SCEVHandle &Imm,
+ const SCEV *&Val, const SCEV *&Imm,
bool isAddress, Loop *L,
ScalarEvolution *SE) {
if (const SCEVAddExpr *SAE = dyn_cast<SCEVAddExpr>(Val)) {
- std::vector<SCEVHandle> NewOps;
+ SmallVector<const SCEV *, 4> NewOps;
NewOps.reserve(SAE->getNumOperands());
for (unsigned i = 0; i != SAE->getNumOperands(); ++i) {
- SCEVHandle NewOp = SAE->getOperand(i);
+ const SCEV *NewOp = SAE->getOperand(i);
MoveImmediateValues(TLI, AccessTy, NewOp, Imm, isAddress, L, SE);
if (!NewOp->isLoopInvariant(L)) {
return;
} else if (const SCEVAddRecExpr *SARE = dyn_cast<SCEVAddRecExpr>(Val)) {
// Try to pull immediates out of the start value of nested addrec's.
- SCEVHandle Start = SARE->getStart();
+ const SCEV *Start = SARE->getStart();
MoveImmediateValues(TLI, AccessTy, Start, Imm, isAddress, L, SE);
if (Start != SARE->getStart()) {
- std::vector<SCEVHandle> Ops(SARE->op_begin(), SARE->op_end());
+ SmallVector<const SCEV *, 4> Ops(SARE->op_begin(), SARE->op_end());
Ops[0] = Start;
Val = SE->getAddRecExpr(Ops, SARE->getLoop());
}
fitsInAddressMode(SME->getOperand(0), AccessTy, TLI, false) &&
SME->getNumOperands() == 2 && SME->isLoopInvariant(L)) {
- SCEVHandle SubImm = SE->getIntegerSCEV(0, Val->getType());
- SCEVHandle NewOp = SME->getOperand(1);
+ const SCEV *SubImm = SE->getIntegerSCEV(0, Val->getType());
+ const SCEV *NewOp = SME->getOperand(1);
MoveImmediateValues(TLI, AccessTy, NewOp, SubImm, isAddress, L, SE);
// If we extracted something out of the subexpressions, see if we can
static void MoveImmediateValues(const TargetLowering *TLI,
Instruction *User,
- SCEVHandle &Val, SCEVHandle &Imm,
+ const SCEV *&Val, const SCEV *&Imm,
bool isAddress, Loop *L,
ScalarEvolution *SE) {
const Type *AccessTy = getAccessType(User);
/// SeparateSubExprs - Decompose Expr into all of the subexpressions that are
/// added together. This is used to reassociate common addition subexprs
/// together for maximal sharing when rewriting bases.
-static void SeparateSubExprs(std::vector<SCEVHandle> &SubExprs,
- SCEVHandle Expr,
+static void SeparateSubExprs(SmallVector<const SCEV *, 16> &SubExprs,
+ const SCEV *Expr,
ScalarEvolution *SE) {
if (const SCEVAddExpr *AE = dyn_cast<SCEVAddExpr>(Expr)) {
for (unsigned j = 0, e = AE->getNumOperands(); j != e; ++j)
SeparateSubExprs(SubExprs, AE->getOperand(j), SE);
} else if (const SCEVAddRecExpr *SARE = dyn_cast<SCEVAddRecExpr>(Expr)) {
- SCEVHandle Zero = SE->getIntegerSCEV(0, Expr->getType());
+ const SCEV *Zero = SE->getIntegerSCEV(0, Expr->getType());
if (SARE->getOperand(0) == Zero) {
SubExprs.push_back(Expr);
} else {
// Compute the addrec with zero as its base.
- std::vector<SCEVHandle> Ops(SARE->op_begin(), SARE->op_end());
+ SmallVector<const SCEV *, 4> Ops(SARE->op_begin(), SARE->op_end());
Ops[0] = Zero; // Start with zero base.
SubExprs.push_back(SE->getAddRecExpr(Ops, SARE->getLoop()));
/// not remove anything. This looks for things like (a+b+c) and
/// (a+c+d) and computes the common (a+c) subexpression. The common expression
/// is *removed* from the Bases and returned.
-static SCEVHandle
+static const SCEV *
RemoveCommonExpressionsFromUseBases(std::vector<BasedUser> &Uses,
ScalarEvolution *SE, Loop *L,
const TargetLowering *TLI) {
// Only one use? This is a very common case, so we handle it specially and
// cheaply.
- SCEVHandle Zero = SE->getIntegerSCEV(0, Uses[0].Base->getType());
- SCEVHandle Result = Zero;
- SCEVHandle FreeResult = Zero;
+ const SCEV *Zero = SE->getIntegerSCEV(0, Uses[0].Base->getType());
+ const SCEV *Result = Zero;
+ const SCEV *FreeResult = Zero;
if (NumUses == 1) {
// If the use is inside the loop, use its base, regardless of what it is:
// it is clearly shared across all the IV's. If the use is outside the loop
// Also track whether all uses of each expression can be moved into an
// an addressing mode "for free"; such expressions are left within the loop.
// struct SubExprUseData { unsigned Count; bool notAllUsesAreFree; };
- std::map<SCEVHandle, SubExprUseData> SubExpressionUseData;
+ std::map<const SCEV *, SubExprUseData> SubExpressionUseData;
// UniqueSubExprs - Keep track of all of the subexpressions we see in the
// order we see them.
- std::vector<SCEVHandle> UniqueSubExprs;
+ SmallVector<const SCEV *, 16> UniqueSubExprs;
- std::vector<SCEVHandle> SubExprs;
+ SmallVector<const SCEV *, 16> SubExprs;
unsigned NumUsesInsideLoop = 0;
for (unsigned i = 0; i != NumUses; ++i) {
// If the user is outside the loop, just ignore it for base computation.
// Now that we know how many times each is used, build Result. Iterate over
// UniqueSubexprs so that we have a stable ordering.
for (unsigned i = 0, e = UniqueSubExprs.size(); i != e; ++i) {
- std::map<SCEVHandle, SubExprUseData>::iterator I =
+ std::map<const SCEV *, SubExprUseData>::iterator I =
SubExpressionUseData.find(UniqueSubExprs[i]);
assert(I != SubExpressionUseData.end() && "Entry not found?");
if (I->second.Count == NumUsesInsideLoop) { // Found CSE!
if (FreeResult != Zero) {
SeparateSubExprs(SubExprs, FreeResult, SE);
for (unsigned j = 0, e = SubExprs.size(); j != e; ++j) {
- std::map<SCEVHandle, SubExprUseData>::iterator I =
+ std::map<const SCEV *, SubExprUseData>::iterator I =
SubExpressionUseData.find(SubExprs[j]);
SubExpressionUseData.erase(I);
}
for (unsigned i = 0, e = UsersToProcess.size(); i!=e; ++i) {
// If this is a load or other access, pass the type of the access in.
- const Type *AccessTy = Type::VoidTy;
+ const Type *AccessTy =
+ Type::getVoidTy(UsersToProcess[i].Inst->getContext());
if (isAddressUse(UsersToProcess[i].Inst,
UsersToProcess[i].OperandValToReplace))
AccessTy = getAccessType(UsersToProcess[i].Inst);
for (unsigned i=0, e = UsersToProcess.size(); i!=e; ++i) {
// If this is a load or other access, pass the type of the access in.
- const Type *AccessTy = Type::VoidTy;
+ const Type *AccessTy =
+ Type::getVoidTy(UsersToProcess[i].Inst->getContext());
if (isAddressUse(UsersToProcess[i].Inst,
UsersToProcess[i].OperandValToReplace))
AccessTy = getAccessType(UsersToProcess[i].Inst);
/// be folded into the addressing mode, nor even that the factor be constant;
/// a multiply (executed once) outside the loop is better than another IV
/// within. Well, usually.
-SCEVHandle LoopStrengthReduce::CheckForIVReuse(bool HasBaseReg,
+const SCEV *LoopStrengthReduce::CheckForIVReuse(bool HasBaseReg,
bool AllUsesAreAddresses,
bool AllUsesAreOutsideLoop,
- const SCEVHandle &Stride,
+ const SCEV *const &Stride,
IVExpr &IV, const Type *Ty,
const std::vector<BasedUser>& UsersToProcess) {
if (StrideNoReuse.count(Stride))
int64_t SInt = SC->getValue()->getSExtValue();
for (unsigned NewStride = 0, e = IU->StrideOrder.size();
NewStride != e; ++NewStride) {
- std::map<SCEVHandle, IVsOfOneStride>::iterator SI =
+ std::map<const SCEV *, IVsOfOneStride>::iterator SI =
IVsByStride.find(IU->StrideOrder[NewStride]);
if (SI == IVsByStride.end() || !isa<SCEVConstant>(SI->first) ||
StrideNoReuse.count(SI->first))
// an existing IV if we can.
for (unsigned NewStride = 0, e = IU->StrideOrder.size();
NewStride != e; ++NewStride) {
- std::map<SCEVHandle, IVsOfOneStride>::iterator SI =
+ std::map<const SCEV *, IVsOfOneStride>::iterator SI =
IVsByStride.find(IU->StrideOrder[NewStride]);
if (SI == IVsByStride.end() || !isa<SCEVConstant>(SI->first))
continue;
// -1*old.
for (unsigned NewStride = 0, e = IU->StrideOrder.size();
NewStride != e; ++NewStride) {
- std::map<SCEVHandle, IVsOfOneStride>::iterator SI =
+ std::map<const SCEV *, IVsOfOneStride>::iterator SI =
IVsByStride.find(IU->StrideOrder[NewStride]);
if (SI == IVsByStride.end())
continue;
/// isNonConstantNegative - Return true if the specified scev is negated, but
/// not a constant.
-static bool isNonConstantNegative(const SCEVHandle &Expr) {
+static bool isNonConstantNegative(const SCEV *const &Expr) {
const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Expr);
if (!Mul) return false;
return SC->getValue()->getValue().isNegative();
}
-// CollectIVUsers - Transform our list of users and offsets to a bit more
-// complex table. In this new vector, each 'BasedUser' contains 'Base', the base
-// of the strided accesses, as well as the old information from Uses. We
-// progressively move information from the Base field to the Imm field, until
-// we eventually have the full access expression to rewrite the use.
-SCEVHandle LoopStrengthReduce::CollectIVUsers(const SCEVHandle &Stride,
+/// CollectIVUsers - Transform our list of users and offsets to a bit more
+/// complex table. In this new vector, each 'BasedUser' contains 'Base', the base
+/// of the strided accesses, as well as the old information from Uses. We
+/// progressively move information from the Base field to the Imm field, until
+/// we eventually have the full access expression to rewrite the use.
+const SCEV *LoopStrengthReduce::CollectIVUsers(const SCEV *const &Stride,
IVUsersOfOneStride &Uses,
Loop *L,
bool &AllUsesAreAddresses,
// for the strides (e.g. if we have "A+C+B" and "A+B+D" as our bases, find
// "A+B"), emit it to the preheader, then remove the expression from the
// UsersToProcess base values.
- SCEVHandle CommonExprs =
+ const SCEV *CommonExprs =
RemoveCommonExpressionsFromUseBases(UsersToProcess, SE, L, TLI);
// Next, figure out what we can represent in the immediate fields of
const std::vector<BasedUser> &UsersToProcess,
const Loop *L,
bool AllUsesAreAddresses,
- SCEVHandle Stride) {
+ const SCEV *Stride) {
if (!EnableFullLSRMode)
return false;
if (!Imm) Imm = SE->getIntegerSCEV(0, Stride->getType());
const Instruction *Inst = UsersToProcess[i].Inst;
const Type *AccessTy = getAccessType(Inst);
- SCEVHandle Diff = SE->getMinusSCEV(UsersToProcess[i].Imm, Imm);
+ const SCEV *Diff = SE->getMinusSCEV(UsersToProcess[i].Imm, Imm);
if (!Diff->isZero() &&
(!AllUsesAreAddresses ||
!fitsInAddressMode(Diff, AccessTy, TLI, /*HasBaseReg=*/true)))
///
/// Return the created phi node.
///
-static PHINode *InsertAffinePhi(SCEVHandle Start, SCEVHandle Step,
+static PHINode *InsertAffinePhi(const SCEV *Start, const SCEV *Step,
Instruction *IVIncInsertPt,
const Loop *L,
SCEVExpander &Rewriter) {
// If the stride is negative, insert a sub instead of an add for the
// increment.
bool isNegative = isNonConstantNegative(Step);
- SCEVHandle IncAmount = Step;
+ const SCEV *IncAmount = Step;
if (isNegative)
IncAmount = Rewriter.SE.getNegativeSCEV(Step);
// loop before users outside of the loop with a particular base.
//
// We would like to use stable_sort here, but we can't. The problem is that
- // SCEVHandle's don't have a deterministic ordering w.r.t to each other, so
+ // const SCEV *'s don't have a deterministic ordering w.r.t to each other, so
// we don't have anything to do a '<' comparison on. Because we think the
// number of uses is small, do a horrible bubble sort which just relies on
// ==.
for (unsigned i = 0, e = UsersToProcess.size(); i != e; ++i) {
// Get a base value.
- SCEVHandle Base = UsersToProcess[i].Base;
+ const SCEV *Base = UsersToProcess[i].Base;
// Compact everything with this base to be consecutive with this one.
for (unsigned j = i+1; j != e; ++j) {
void
LoopStrengthReduce::PrepareToStrengthReduceFully(
std::vector<BasedUser> &UsersToProcess,
- SCEVHandle Stride,
- SCEVHandle CommonExprs,
+ const SCEV *Stride,
+ const SCEV *CommonExprs,
const Loop *L,
SCEVExpander &PreheaderRewriter) {
- DOUT << " Fully reducing all users\n";
+ DEBUG(errs() << " Fully reducing all users\n");
// Rewrite the UsersToProcess records, creating a separate PHI for each
// unique Base value.
// TODO: The uses are grouped by base, but not sorted. We arbitrarily
// pick the first Imm value here to start with, and adjust it for the
// other uses.
- SCEVHandle Imm = UsersToProcess[i].Imm;
- SCEVHandle Base = UsersToProcess[i].Base;
- SCEVHandle Start = SE->getAddExpr(CommonExprs, Base, Imm);
+ const SCEV *Imm = UsersToProcess[i].Imm;
+ const SCEV *Base = UsersToProcess[i].Base;
+ const SCEV *Start = SE->getAddExpr(CommonExprs, Base, Imm);
PHINode *Phi = InsertAffinePhi(Start, Stride, IVIncInsertPt, L,
PreheaderRewriter);
// Loop over all the users with the same base.
void
LoopStrengthReduce::PrepareToStrengthReduceWithNewPhi(
std::vector<BasedUser> &UsersToProcess,
- SCEVHandle Stride,
- SCEVHandle CommonExprs,
+ const SCEV *Stride,
+ const SCEV *CommonExprs,
Value *CommonBaseV,
Instruction *IVIncInsertPt,
const Loop *L,
SCEVExpander &PreheaderRewriter) {
- DOUT << " Inserting new PHI:\n";
+ DEBUG(errs() << " Inserting new PHI:\n");
PHINode *Phi = InsertAffinePhi(SE->getUnknown(CommonBaseV),
Stride, IVIncInsertPt, L,
for (unsigned i = 0, e = UsersToProcess.size(); i != e; ++i)
UsersToProcess[i].Phi = Phi;
- DOUT << " IV=";
- DEBUG(WriteAsOperand(*DOUT, Phi, /*PrintType=*/false));
- DOUT << "\n";
+ DEBUG(errs() << " IV=");
+ DEBUG(WriteAsOperand(errs(), Phi, /*PrintType=*/false));
+ DEBUG(errs() << "\n");
}
/// PrepareToStrengthReduceFromSmallerStride - Prepare for the given users to
Value *CommonBaseV,
const IVExpr &ReuseIV,
Instruction *PreInsertPt) {
- DOUT << " Rewriting in terms of existing IV of STRIDE " << *ReuseIV.Stride
- << " and BASE " << *ReuseIV.Base << "\n";
+ DEBUG(errs() << " Rewriting in terms of existing IV of STRIDE "
+ << *ReuseIV.Stride << " and BASE " << *ReuseIV.Base << "\n");
// All the users will share the reused IV.
for (unsigned i = 0, e = UsersToProcess.size(); i != e; ++i)
/// StrengthReduceStridedIVUsers - Strength reduce all of the users of a single
/// stride of IV. All of the users may have different starting values, and this
/// may not be the only stride.
-void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
+void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEV *const &Stride,
IVUsersOfOneStride &Uses,
Loop *L) {
// If all the users are moved to another stride, then there is nothing to do.
// move information from the Base field to the Imm field, until we eventually
// have the full access expression to rewrite the use.
std::vector<BasedUser> UsersToProcess;
- SCEVHandle CommonExprs = CollectIVUsers(Stride, Uses, L, AllUsesAreAddresses,
+ const SCEV *CommonExprs = CollectIVUsers(Stride, Uses, L, AllUsesAreAddresses,
AllUsesAreOutsideLoop,
UsersToProcess);
// If all uses are addresses, consider sinking the immediate part of the
// common expression back into uses if they can fit in the immediate fields.
if (TLI && HaveCommonExprs && AllUsesAreAddresses) {
- SCEVHandle NewCommon = CommonExprs;
- SCEVHandle Imm = SE->getIntegerSCEV(0, ReplacedTy);
- MoveImmediateValues(TLI, Type::VoidTy, NewCommon, Imm, true, L, SE);
+ const SCEV *NewCommon = CommonExprs;
+ const SCEV *Imm = SE->getIntegerSCEV(0, ReplacedTy);
+ MoveImmediateValues(TLI, Type::getVoidTy(
+ L->getLoopPreheader()->getContext()),
+ NewCommon, Imm, true, L, SE);
if (!Imm->isZero()) {
bool DoSink = true;
if (GV || Offset)
// Pass VoidTy as the AccessTy to be conservative, because
// there could be multiple access types among all the uses.
- DoSink = IsImmFoldedIntoAddrMode(GV, Offset, Type::VoidTy,
+ DoSink = IsImmFoldedIntoAddrMode(GV, Offset,
+ Type::getVoidTy(L->getLoopPreheader()->getContext()),
UsersToProcess, TLI);
if (DoSink) {
- DOUT << " Sinking " << *Imm << " back down into uses\n";
+ DEBUG(errs() << " Sinking " << *Imm << " back down into uses\n");
for (unsigned i = 0, e = UsersToProcess.size(); i != e; ++i)
UsersToProcess[i].Imm = SE->getAddExpr(UsersToProcess[i].Imm, Imm);
CommonExprs = NewCommon;
// Now that we know what we need to do, insert the PHI node itself.
//
- DOUT << "LSR: Examining IVs of TYPE " << *ReplacedTy << " of STRIDE "
- << *Stride << ":\n"
- << " Common base: " << *CommonExprs << "\n";
+ DEBUG(errs() << "LSR: Examining IVs of TYPE " << *ReplacedTy << " of STRIDE "
+ << *Stride << ":\n"
+ << " Common base: " << *CommonExprs << "\n");
SCEVExpander Rewriter(*SE);
SCEVExpander PreheaderRewriter(*SE);
Value *CommonBaseV = Constant::getNullValue(ReplacedTy);
- SCEVHandle RewriteFactor = SE->getIntegerSCEV(0, ReplacedTy);
- IVExpr ReuseIV(SE->getIntegerSCEV(0, Type::Int32Ty),
- SE->getIntegerSCEV(0, Type::Int32Ty),
+ const SCEV *RewriteFactor = SE->getIntegerSCEV(0, ReplacedTy);
+ IVExpr ReuseIV(SE->getIntegerSCEV(0,
+ Type::getInt32Ty(Preheader->getContext())),
+ SE->getIntegerSCEV(0,
+ Type::getInt32Ty(Preheader->getContext())),
0);
/// Choose a strength-reduction strategy and prepare for it by creating
// strength-reduced forms. This outer loop handles all bases, the inner
// loop handles all users of a particular base.
while (!UsersToProcess.empty()) {
- SCEVHandle Base = UsersToProcess.back().Base;
+ const SCEV *Base = UsersToProcess.back().Base;
Instruction *Inst = UsersToProcess.back().Inst;
// Emit the code for Base into the preheader.
if (!Base->isZero()) {
BaseV = PreheaderRewriter.expandCodeFor(Base, 0, PreInsertPt);
- DOUT << " INSERTING code for BASE = " << *Base << ":";
+ DEBUG(errs() << " INSERTING code for BASE = " << *Base << ":");
if (BaseV->hasName())
- DOUT << " Result value name = %" << BaseV->getNameStr();
- DOUT << "\n";
+ DEBUG(errs() << " Result value name = %" << BaseV->getName());
+ DEBUG(errs() << "\n");
// If BaseV is a non-zero constant, make sure that it gets inserted into
// the preheader, instead of being forward substituted into the uses. We
// do this by forcing a BitCast (noop cast) to be inserted into the
// preheader in this case.
- if (!fitsInAddressMode(Base, getAccessType(Inst), TLI, false)) {
+ if (!fitsInAddressMode(Base, getAccessType(Inst), TLI, false) &&
+ isa<Constant>(BaseV)) {
// We want this constant emitted into the preheader! This is just
// using cast as a copy so BitCast (no-op cast) is appropriate
BaseV = new BitCastInst(BaseV, BaseV->getType(), "preheaderinsert",
// FIXME: Use emitted users to emit other users.
BasedUser &User = UsersToProcess.back();
- DOUT << " Examining ";
+ DEBUG(errs() << " Examining ");
if (User.isUseOfPostIncrementedValue)
- DOUT << "postinc";
+ DEBUG(errs() << "postinc");
else
- DOUT << "preinc";
- DOUT << " use ";
- DEBUG(WriteAsOperand(*DOUT, UsersToProcess.back().OperandValToReplace,
+ DEBUG(errs() << "preinc");
+ DEBUG(errs() << " use ");
+ DEBUG(WriteAsOperand(errs(), UsersToProcess.back().OperandValToReplace,
/*PrintType=*/false));
- DOUT << " in Inst: " << *(User.Inst);
+ DEBUG(errs() << " in Inst: " << *User.Inst);
// If this instruction wants to use the post-incremented value, move it
// after the post-inc and use its value instead of the PHI.
User.Inst->moveBefore(IVIncInsertPt);
}
- SCEVHandle RewriteExpr = SE->getUnknown(RewriteOp);
+ const SCEV *RewriteExpr = SE->getUnknown(RewriteOp);
if (SE->getEffectiveSCEVType(RewriteOp->getType()) !=
SE->getEffectiveSCEVType(ReplacedTy)) {
// The base has been used to initialize the PHI node but we don't want
// it here.
if (!ReuseIV.Base->isZero()) {
- SCEVHandle typedBase = ReuseIV.Base;
+ const SCEV *typedBase = ReuseIV.Base;
if (SE->getEffectiveSCEVType(RewriteExpr->getType()) !=
SE->getEffectiveSCEVType(ReuseIV.Base->getType())) {
// It's possible the original IV is a larger type than the new IV,
/// set the IV user and stride information and return true, otherwise return
/// false.
bool LoopStrengthReduce::FindIVUserForCond(ICmpInst *Cond, IVStrideUse *&CondUse,
- const SCEVHandle *&CondStride) {
+ const SCEV *const * &CondStride) {
for (unsigned Stride = 0, e = IU->StrideOrder.size();
Stride != e && !CondUse; ++Stride) {
- std::map<SCEVHandle, IVUsersOfOneStride *>::iterator SI =
+ std::map<const SCEV *, IVUsersOfOneStride *>::iterator SI =
IU->IVUsesByStride.find(IU->StrideOrder[Stride]);
assert(SI != IU->IVUsesByStride.end() && "Stride doesn't exist!");
const ScalarEvolution *SE;
explicit StrideCompare(const ScalarEvolution *se) : SE(se) {}
- bool operator()(const SCEVHandle &LHS, const SCEVHandle &RHS) {
+ bool operator()(const SCEV *const &LHS, const SCEV *const &RHS) {
const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS);
const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS);
if (LHSC && RHSC) {
/// if (v1 < 30) goto loop
ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond,
IVStrideUse* &CondUse,
- const SCEVHandle* &CondStride) {
+ const SCEV *const* &CondStride) {
// If there's only one stride in the loop, there's nothing to do here.
if (IU->StrideOrder.size() < 2)
return Cond;
// If there are other users of the condition's stride, don't bother
// trying to change the condition because the stride will still
// remain.
- std::map<SCEVHandle, IVUsersOfOneStride *>::iterator I =
+ std::map<const SCEV *, IVUsersOfOneStride *>::iterator I =
IU->IVUsesByStride.find(*CondStride);
if (I == IU->IVUsesByStride.end() ||
I->second->Users.size() != 1)
const Type *NewCmpTy = NULL;
unsigned TyBits = SE->getTypeSizeInBits(CmpTy);
unsigned NewTyBits = 0;
- SCEVHandle *NewStride = NULL;
+ const SCEV **NewStride = NULL;
Value *NewCmpLHS = NULL;
Value *NewCmpRHS = NULL;
int64_t Scale = 1;
- SCEVHandle NewOffset = SE->getIntegerSCEV(0, CmpTy);
+ const SCEV *NewOffset = SE->getIntegerSCEV(0, CmpTy);
if (ConstantInt *C = dyn_cast<ConstantInt>(Cond->getOperand(1))) {
int64_t CmpVal = C->getValue().getSExtValue();
// Look for a suitable stride / iv as replacement.
for (unsigned i = 0, e = IU->StrideOrder.size(); i != e; ++i) {
- std::map<SCEVHandle, IVUsersOfOneStride *>::iterator SI =
+ std::map<const SCEV *, IVUsersOfOneStride *>::iterator SI =
IU->IVUsesByStride.find(IU->StrideOrder[i]);
if (!isa<SCEVConstant>(SI->first))
continue;
NewCmpTy = NewCmpLHS->getType();
NewTyBits = SE->getTypeSizeInBits(NewCmpTy);
- const Type *NewCmpIntTy = IntegerType::get(NewTyBits);
+ const Type *NewCmpIntTy = IntegerType::get(Cond->getContext(), NewTyBits);
if (RequiresTypeConversion(NewCmpTy, CmpTy)) {
// Check if it is possible to rewrite it using
// an iv / stride of a smaller integer type.
bool AllUsesAreAddresses = true;
bool AllUsesAreOutsideLoop = true;
std::vector<BasedUser> UsersToProcess;
- SCEVHandle CommonExprs = CollectIVUsers(SI->first, *SI->second, L,
+ const SCEV *CommonExprs = CollectIVUsers(SI->first, *SI->second, L,
AllUsesAreAddresses,
AllUsesAreOutsideLoop,
UsersToProcess);
ValidScale(!CommonExprs->isZero(), Scale, UsersToProcess))
continue;
+ // Avoid rewriting the compare instruction with an iv which has
+ // implicit extension or truncation built into it.
+ // TODO: This is over-conservative.
+ if (SE->getTypeSizeInBits(CondUse->getOffset()->getType()) != TyBits)
+ continue;
+
// If scale is negative, use swapped predicate unless it's testing
// for equality.
if (Scale < 0 && !Cond->isEquality())
if (!isa<PointerType>(NewCmpTy))
NewCmpRHS = ConstantInt::get(NewCmpTy, NewCmpVal);
else {
- ConstantInt *CI = ConstantInt::get(NewCmpIntTy, NewCmpVal);
+ Constant *CI = ConstantInt::get(NewCmpIntTy, NewCmpVal);
NewCmpRHS = ConstantExpr::getIntToPtr(CI, NewCmpTy);
}
NewOffset = TyBits == NewTyBits
? SE->getMulExpr(CondUse->getOffset(),
- SE->getConstant(ConstantInt::get(CmpTy, Scale)))
- : SE->getConstant(ConstantInt::get(NewCmpIntTy,
+ SE->getConstant(CmpTy, Scale))
+ : SE->getConstant(NewCmpIntTy,
cast<SCEVConstant>(CondUse->getOffset())->getValue()
- ->getSExtValue()*Scale));
+ ->getSExtValue()*Scale);
break;
}
}
// Create a new compare instruction using new stride / iv.
ICmpInst *OldCond = Cond;
// Insert new compare instruction.
- Cond = new ICmpInst(Predicate, NewCmpLHS, NewCmpRHS,
- L->getHeader()->getName() + ".termcond",
- OldCond);
+ Cond = new ICmpInst(OldCond, Predicate, NewCmpLHS, NewCmpRHS,
+ L->getHeader()->getName() + ".termcond");
// Remove the old compare instruction. The old indvar is probably dead too.
DeadInsts.push_back(CondUse->getOperandValToReplace());
OldCond->replaceAllUsesWith(Cond);
OldCond->eraseFromParent();
- IU->IVUsesByStride[*NewStride]->addUser(NewOffset, Cond, NewCmpLHS, false);
+ IU->IVUsesByStride[*NewStride]->addUser(NewOffset, Cond, NewCmpLHS);
CondUse = &IU->IVUsesByStride[*NewStride]->Users.back();
CondStride = NewStride;
++NumEliminated;
return Cond;
}
-/// OptimizeSMax - Rewrite the loop's terminating condition if it uses
-/// an smax computation.
+/// OptimizeMax - Rewrite the loop's terminating condition if it uses
+/// a max computation.
///
/// This is a narrow solution to a specific, but acute, problem. For loops
/// like this:
/// p[i] = 0.0;
/// } while (++i < n);
///
-/// where the comparison is signed, the trip count isn't just 'n', because
-/// 'n' could be negative. And unfortunately this can come up even for loops
-/// where the user didn't use a C do-while loop. For example, seemingly
-/// well-behaved top-test loops will commonly be lowered like this:
+/// the trip count isn't just 'n', because 'n' might not be positive. And
+/// unfortunately this can come up even for loops where the user didn't use
+/// a C do-while loop. For example, seemingly well-behaved top-test loops
+/// will commonly be lowered like this:
//
/// if (n > 0) {
/// i = 0;
/// test in such a way that indvars can't find it.
///
/// When indvars can't find the if test in loops like this, it creates a
-/// signed-max expression, which allows it to give the loop a canonical
+/// max expression, which allows it to give the loop a canonical
/// induction variable:
///
/// i = 0;
-/// smax = n < 1 ? 1 : n;
+/// max = n < 1 ? 1 : n;
/// do {
/// p[i] = 0.0;
-/// } while (++i != smax);
+/// } while (++i != max);
///
/// Canonical induction variables are necessary because the loop passes
/// are designed around them. The most obvious example of this is the
/// rewriting their conditions from ICMP_NE back to ICMP_SLT, and deleting
/// the instructions for the maximum computation.
///
-ICmpInst *LoopStrengthReduce::OptimizeSMax(Loop *L, ICmpInst *Cond,
- IVStrideUse* &CondUse) {
+ICmpInst *LoopStrengthReduce::OptimizeMax(Loop *L, ICmpInst *Cond,
+ IVStrideUse* &CondUse) {
// Check that the loop matches the pattern we're looking for.
if (Cond->getPredicate() != CmpInst::ICMP_EQ &&
Cond->getPredicate() != CmpInst::ICMP_NE)
SelectInst *Sel = dyn_cast<SelectInst>(Cond->getOperand(1));
if (!Sel || !Sel->hasOneUse()) return Cond;
- SCEVHandle BackedgeTakenCount = SE->getBackedgeTakenCount(L);
+ const SCEV *BackedgeTakenCount = SE->getBackedgeTakenCount(L);
if (isa<SCEVCouldNotCompute>(BackedgeTakenCount))
return Cond;
- SCEVHandle One = SE->getIntegerSCEV(1, BackedgeTakenCount->getType());
+ const SCEV *One = SE->getIntegerSCEV(1, BackedgeTakenCount->getType());
// Add one to the backedge-taken count to get the trip count.
- SCEVHandle IterationCount = SE->getAddExpr(BackedgeTakenCount, One);
+ const SCEV *IterationCount = SE->getAddExpr(BackedgeTakenCount, One);
// Check for a max calculation that matches the pattern.
- const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(IterationCount);
- if (!SMax || SMax != SE->getSCEV(Sel)) return Cond;
+ if (!isa<SCEVSMaxExpr>(IterationCount) && !isa<SCEVUMaxExpr>(IterationCount))
+ return Cond;
+ const SCEVNAryExpr *Max = cast<SCEVNAryExpr>(IterationCount);
+ if (Max != SE->getSCEV(Sel)) return Cond;
- SCEVHandle SMaxLHS = SMax->getOperand(0);
- SCEVHandle SMaxRHS = SMax->getOperand(1);
- if (!SMaxLHS || SMaxLHS != One) return Cond;
+ // To handle a max with more than two operands, this optimization would
+ // require additional checking and setup.
+ if (Max->getNumOperands() != 2)
+ return Cond;
+
+ const SCEV *MaxLHS = Max->getOperand(0);
+ const SCEV *MaxRHS = Max->getOperand(1);
+ if (!MaxLHS || MaxLHS != One) return Cond;
// Check the relevant induction variable for conformance to
// the pattern.
- SCEVHandle IV = SE->getSCEV(Cond->getOperand(0));
+ const SCEV *IV = SE->getSCEV(Cond->getOperand(0));
const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(IV);
if (!AR || !AR->isAffine() ||
AR->getStart() != One ||
// Check the right operand of the select, and remember it, as it will
// be used in the new comparison instruction.
Value *NewRHS = 0;
- if (SE->getSCEV(Sel->getOperand(1)) == SMaxRHS)
+ if (SE->getSCEV(Sel->getOperand(1)) == MaxRHS)
NewRHS = Sel->getOperand(1);
- else if (SE->getSCEV(Sel->getOperand(2)) == SMaxRHS)
+ else if (SE->getSCEV(Sel->getOperand(2)) == MaxRHS)
NewRHS = Sel->getOperand(2);
if (!NewRHS) return Cond;
+ // Determine the new comparison opcode. It may be signed or unsigned,
+ // and the original comparison may be either equality or inequality.
+ CmpInst::Predicate Pred =
+ isa<SCEVSMaxExpr>(Max) ? CmpInst::ICMP_SLT : CmpInst::ICMP_ULT;
+ if (Cond->getPredicate() == CmpInst::ICMP_EQ)
+ Pred = CmpInst::getInversePredicate(Pred);
+
// Ok, everything looks ok to change the condition into an SLT or SGE and
// delete the max calculation.
ICmpInst *NewCond =
- new ICmpInst(Cond->getPredicate() == CmpInst::ICMP_NE ?
- CmpInst::ICMP_SLT :
- CmpInst::ICMP_SGE,
- Cond->getOperand(0), NewRHS, "scmp", Cond);
+ new ICmpInst(Cond, Pred, Cond->getOperand(0), NewRHS, "scmp");
// Delete the max calculation instructions.
Cond->replaceAllUsesWith(NewCond);
/// inside the loop then try to eliminate the cast opeation.
void LoopStrengthReduce::OptimizeShadowIV(Loop *L) {
- SCEVHandle BackedgeTakenCount = SE->getBackedgeTakenCount(L);
+ const SCEV *BackedgeTakenCount = SE->getBackedgeTakenCount(L);
if (isa<SCEVCouldNotCompute>(BackedgeTakenCount))
return;
-
+
for (unsigned Stride = 0, e = IU->StrideOrder.size(); Stride != e;
++Stride) {
- std::map<SCEVHandle, IVUsersOfOneStride *>::iterator SI =
+ std::map<const SCEV *, IVUsersOfOneStride *>::iterator SI =
IU->IVUsesByStride.find(IU->StrideOrder[Stride]);
assert(SI != IU->IVUsesByStride.end() && "Stride doesn't exist!");
if (!isa<SCEVConstant>(SI->first))
if (TLI) {
// If target does not support DestTy natively then do not apply
// this transformation.
- MVT DVT = TLI->getValueType(DestTy);
+ EVT DVT = TLI->getValueType(DestTy);
if (!TLI->isTypeLegal(DVT)) continue;
}
ConstantInt *Init = dyn_cast<ConstantInt>(PH->getIncomingValue(Entry));
if (!Init) continue;
- ConstantFP *NewInit = ConstantFP::get(DestTy, Init->getZExtValue());
+ Constant *NewInit = ConstantFP::get(DestTy, Init->getZExtValue());
BinaryOperator *Incr =
dyn_cast<BinaryOperator>(PH->getIncomingValue(Latch));
PHINode *NewPH = PHINode::Create(DestTy, "IV.S.", PH);
/* create new increment. '++d' in above example. */
- ConstantFP *CFP = ConstantFP::get(DestTy, C->getZExtValue());
+ Constant *CFP = ConstantFP::get(DestTy, C->getZExtValue());
BinaryOperator *NewIncr =
- BinaryOperator::Create(Incr->getOpcode(),
+ BinaryOperator::Create(Incr->getOpcode() == Instruction::Add ?
+ Instruction::FAdd : Instruction::FSub,
NewPH, CFP, "IV.S.next.", Incr);
NewPH->addIncoming(NewInit, PH->getIncomingBlock(Entry));
}
}
-// OptimizeIndvars - Now that IVUsesByStride is set up with all of the indvar
-// uses in the loop, look to see if we can eliminate some, in favor of using
-// common indvars for the different uses.
+/// OptimizeIndvars - Now that IVUsesByStride is set up with all of the indvar
+/// uses in the loop, look to see if we can eliminate some, in favor of using
+/// common indvars for the different uses.
void LoopStrengthReduce::OptimizeIndvars(Loop *L) {
// TODO: implement optzns here.
// induction variable, to allow coalescing the live ranges for the IV into
// one register value.
BasicBlock *LatchBlock = L->getLoopLatch();
- BasicBlock *ExitBlock = L->getExitingBlock();
- if (!ExitBlock)
+ BasicBlock *ExitingBlock = L->getExitingBlock();
+
+ if (!ExitingBlock)
// Multiple exits, just look at the exit in the latch block if there is one.
- ExitBlock = LatchBlock;
- BranchInst *TermBr = dyn_cast<BranchInst>(ExitBlock->getTerminator());
+ ExitingBlock = LatchBlock;
+ BranchInst *TermBr = dyn_cast<BranchInst>(ExitingBlock->getTerminator());
if (!TermBr)
return;
if (TermBr->isUnconditional() || !isa<ICmpInst>(TermBr->getCondition()))
// Search IVUsesByStride to find Cond's IVUse if there is one.
IVStrideUse *CondUse = 0;
- const SCEVHandle *CondStride = 0;
+ const SCEV *const *CondStride = 0;
ICmpInst *Cond = cast<ICmpInst>(TermBr->getCondition());
if (!FindIVUserForCond(Cond, CondUse, CondStride))
return; // setcc doesn't use the IV.
- if (ExitBlock != LatchBlock) {
+ if (ExitingBlock != LatchBlock) {
if (!Cond->hasOneUse())
// See below, we don't want the condition to be cloned.
return;
int64_t SInt = SC->getValue()->getSExtValue();
for (unsigned NewStride = 0, ee = IU->StrideOrder.size(); NewStride != ee;
++NewStride) {
- std::map<SCEVHandle, IVUsersOfOneStride *>::iterator SI =
+ std::map<const SCEV *, IVUsersOfOneStride *>::iterator SI =
IU->IVUsesByStride.find(IU->StrideOrder[NewStride]);
if (!isa<SCEVConstant>(SI->first) || SI->first == *CondStride)
continue;
bool AllUsesAreAddresses = true;
bool AllUsesAreOutsideLoop = true;
std::vector<BasedUser> UsersToProcess;
- SCEVHandle CommonExprs = CollectIVUsers(SI->first, *SI->second, L,
+ const SCEV *CommonExprs = CollectIVUsers(SI->first, *SI->second, L,
AllUsesAreAddresses,
AllUsesAreOutsideLoop,
UsersToProcess);
StrideNoReuse.insert(*CondStride);
}
- // If the trip count is computed in terms of an smax (due to ScalarEvolution
+ // If the trip count is computed in terms of a max (due to ScalarEvolution
// being unable to find a sufficient guard, for example), change the loop
- // comparison to use SLT instead of NE.
- Cond = OptimizeSMax(L, Cond, CondUse);
+ // comparison to use SLT or ULT instead of NE.
+ Cond = OptimizeMax(L, Cond, CondUse);
// If possible, change stride and operands of the compare instruction to
// eliminate one stride.
- if (ExitBlock == LatchBlock)
+ if (ExitingBlock == LatchBlock)
Cond = ChangeCompareStride(L, Cond, CondUse, CondStride);
// It's possible for the setcc instruction to be anywhere in the loop, and
// Clone the IVUse, as the old use still exists!
IU->IVUsesByStride[*CondStride]->addUser(CondUse->getOffset(), Cond,
- CondUse->getOperandValToReplace(),
- false);
+ CondUse->getOperandValToReplace());
CondUse = &IU->IVUsesByStride[*CondStride]->Users.back();
}
}
++NumLoopCond;
}
-// OptimizeLoopCountIV - If, after all sharing of IVs, the IV used for deciding
-// when to exit the loop is used only for that purpose, try to rearrange things
-// so it counts down to a test against zero.
+/// OptimizeLoopCountIV - If, after all sharing of IVs, the IV used for deciding
+/// when to exit the loop is used only for that purpose, try to rearrange things
+/// so it counts down to a test against zero.
void LoopStrengthReduce::OptimizeLoopCountIV(Loop *L) {
// If the number of times the loop is executed isn't computable, give up.
- SCEVHandle BackedgeTakenCount = SE->getBackedgeTakenCount(L);
+ const SCEV *BackedgeTakenCount = SE->getBackedgeTakenCount(L);
if (isa<SCEVCouldNotCompute>(BackedgeTakenCount))
return;
// Get the terminating condition for the loop if possible (this isn't
// necessarily in the latch, or a block that's a predecessor of the header).
- SmallVector<BasicBlock*, 8> ExitBlocks;
- L->getExitBlocks(ExitBlocks);
- if (ExitBlocks.size() != 1) return;
+ if (!L->getExitBlock())
+ return; // More than one loop exit blocks.
// Okay, there is one exit block. Try to find the condition that causes the
// loop to be exited.
- BasicBlock *ExitBlock = ExitBlocks[0];
-
- BasicBlock *ExitingBlock = 0;
- for (pred_iterator PI = pred_begin(ExitBlock), E = pred_end(ExitBlock);
- PI != E; ++PI)
- if (L->contains(*PI)) {
- if (ExitingBlock == 0)
- ExitingBlock = *PI;
- else
- return; // More than one block exiting!
- }
- assert(ExitingBlock && "No exits from loop, something is broken!");
+ BasicBlock *ExitingBlock = L->getExitingBlock();
+ if (!ExitingBlock)
+ return; // More than one block exiting!
// Okay, we've computed the exiting block. See what condition causes us to
// exit.
// Handle only tests for equality for the moment, and only stride 1.
if (Cond->getPredicate() != CmpInst::ICMP_EQ)
return;
- SCEVHandle IV = SE->getSCEV(Cond->getOperand(0));
+ const SCEV *IV = SE->getSCEV(Cond->getOperand(0));
const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(IV);
- SCEVHandle One = SE->getIntegerSCEV(1, BackedgeTakenCount->getType());
+ const SCEV *One = SE->getIntegerSCEV(1, BackedgeTakenCount->getType());
if (!AR || !AR->isAffine() || AR->getStepRecurrence(*SE) != One)
return;
+ // If the RHS of the comparison is defined inside the loop, the rewrite
+ // cannot be done.
+ if (Instruction *CR = dyn_cast<Instruction>(Cond->getOperand(1)))
+ if (L->contains(CR->getParent()))
+ return;
// Make sure the IV is only used for counting. Value may be preinc or
// postinc; 2 uses in either case.
Value *startVal = phi->getIncomingValue(inBlock);
Value *endVal = Cond->getOperand(1);
// FIXME check for case where both are constant
- ConstantInt* Zero = ConstantInt::get(Cond->getOperand(1)->getType(), 0);
+ Constant* Zero = ConstantInt::get(Cond->getOperand(1)->getType(), 0);
BinaryOperator *NewStartVal =
BinaryOperator::Create(Instruction::Sub, endVal, startVal,
"tmp", PreInsertPt);
Changed = false;
if (!IU->IVUsesByStride.empty()) {
-#ifndef NDEBUG
- DOUT << "\nLSR on \"" << L->getHeader()->getParent()->getNameStart()
- << "\" ";
- DEBUG(L->dump());
-#endif
+ DEBUG(errs() << "\nLSR on \"" << L->getHeader()->getParent()->getName()
+ << "\" ";
+ L->dump());
// Sort the StrideOrder so we process larger strides first.
std::stable_sort(IU->StrideOrder.begin(), IU->StrideOrder.end(),
// strides deterministic - not dependent on map order.
for (unsigned Stride = 0, e = IU->StrideOrder.size();
Stride != e; ++Stride) {
- std::map<SCEVHandle, IVUsersOfOneStride *>::iterator SI =
+ std::map<const SCEV *, IVUsersOfOneStride *>::iterator SI =
IU->IVUsesByStride.find(IU->StrideOrder[Stride]);
assert(SI != IU->IVUsesByStride.end() && "Stride doesn't exist!");
// FIXME: Generalize to non-affine IV's.
projects / oota-llvm.git / blobdiff