//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/LLVMContext.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/ADT/STLExtras.h"
using namespace llvm;
-/// InsertCastOfTo - Insert a cast of V to the specified type, doing what
-/// we can to share the casts.
-Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V,
- const Type *Ty) {
- // FIXME: keep track of the cast instruction.
+/// InsertNoopCastOfTo - Insert a cast of V to the specified type,
+/// which must be possible with a noop cast, doing what we can to share
+/// the casts.
+Value *SCEVExpander::InsertNoopCastOfTo(Value *V, const Type *Ty) {
+ Instruction::CastOps Op = CastInst::getCastOpcode(V, false, Ty, false);
+ assert((Op == Instruction::BitCast ||
+ Op == Instruction::PtrToInt ||
+ Op == Instruction::IntToPtr) &&
+ "InsertNoopCastOfTo cannot perform non-noop casts!");
+ assert(SE.getTypeSizeInBits(V->getType()) == SE.getTypeSizeInBits(Ty) &&
+ "InsertNoopCastOfTo cannot change sizes!");
+
+ // Short-circuit unnecessary bitcasts.
+ if (Op == Instruction::BitCast && V->getType() == Ty)
+ return V;
+
+ // Short-circuit unnecessary inttoptr<->ptrtoint casts.
+ if ((Op == Instruction::PtrToInt || Op == Instruction::IntToPtr) &&
+ SE.getTypeSizeInBits(Ty) == SE.getTypeSizeInBits(V->getType())) {
+ if (CastInst *CI = dyn_cast<CastInst>(V))
+ if ((CI->getOpcode() == Instruction::PtrToInt ||
+ CI->getOpcode() == Instruction::IntToPtr) &&
+ SE.getTypeSizeInBits(CI->getType()) ==
+ SE.getTypeSizeInBits(CI->getOperand(0)->getType()))
+ return CI->getOperand(0);
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
+ if ((CE->getOpcode() == Instruction::PtrToInt ||
+ CE->getOpcode() == Instruction::IntToPtr) &&
+ SE.getTypeSizeInBits(CE->getType()) ==
+ SE.getTypeSizeInBits(CE->getOperand(0)->getType()))
+ return CE->getOperand(0);
+ }
+
if (Constant *C = dyn_cast<Constant>(V))
- return ConstantExpr::getCast(opcode, C, Ty);
-
+ return ConstantExpr::getCast(Op, C, Ty);
+
if (Argument *A = dyn_cast<Argument>(V)) {
// Check to see if there is already a cast!
for (Value::use_iterator UI = A->use_begin(), E = A->use_end();
- UI != E; ++UI) {
+ UI != E; ++UI)
if ((*UI)->getType() == Ty)
- if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI))) {
- // If the cast isn't the first instruction of the function, move it.
- if (BasicBlock::iterator(CI) !=
- A->getParent()->getEntryBlock().begin()) {
- CI->moveBefore(A->getParent()->getEntryBlock().begin());
+ if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI)))
+ if (CI->getOpcode() == Op) {
+ // If the cast isn't the first instruction of the function, move it.
+ if (BasicBlock::iterator(CI) !=
+ A->getParent()->getEntryBlock().begin()) {
+ // Recreate the cast at the beginning of the entry block.
+ // The old cast is left in place in case it is being used
+ // as an insert point.
+ Instruction *NewCI =
+ CastInst::Create(Op, V, Ty, "",
+ A->getParent()->getEntryBlock().begin());
+ NewCI->takeName(CI);
+ CI->replaceAllUsesWith(NewCI);
+ return NewCI;
+ }
+ return CI;
}
- return CI;
- }
- }
- return CastInst::create(opcode, V, Ty, V->getName(),
- A->getParent()->getEntryBlock().begin());
+
+ Instruction *I = CastInst::Create(Op, V, Ty, V->getName(),
+ A->getParent()->getEntryBlock().begin());
+ rememberInstruction(I);
+ return I;
}
-
+
Instruction *I = cast<Instruction>(V);
-
+
// Check to see if there is already a cast. If there is, use it.
for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
UI != E; ++UI) {
if ((*UI)->getType() == Ty)
- if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI))) {
- BasicBlock::iterator It = I; ++It;
- if (isa<InvokeInst>(I))
- It = cast<InvokeInst>(I)->getNormalDest()->begin();
- while (isa<PHINode>(It)) ++It;
- if (It != BasicBlock::iterator(CI)) {
- // Splice the cast immediately after the operand in question.
- CI->moveBefore(It);
+ if (CastInst *CI = dyn_cast<CastInst>(cast<Instruction>(*UI)))
+ if (CI->getOpcode() == Op) {
+ BasicBlock::iterator It = I; ++It;
+ if (isa<InvokeInst>(I))
+ It = cast<InvokeInst>(I)->getNormalDest()->begin();
+ while (isa<PHINode>(It)) ++It;
+ if (It != BasicBlock::iterator(CI)) {
+ // Recreate the cast after the user.
+ // The old cast is left in place in case it is being used
+ // as an insert point.
+ Instruction *NewCI = CastInst::Create(Op, V, Ty, "", It);
+ NewCI->takeName(CI);
+ CI->replaceAllUsesWith(NewCI);
+ rememberInstruction(NewCI);
+ return NewCI;
+ }
+ rememberInstruction(CI);
+ return CI;
}
- return CI;
- }
}
BasicBlock::iterator IP = I; ++IP;
if (InvokeInst *II = dyn_cast<InvokeInst>(I))
IP = II->getNormalDest()->begin();
while (isa<PHINode>(IP)) ++IP;
- return CastInst::create(opcode, V, Ty, V->getName(), IP);
+ Instruction *CI = CastInst::Create(Op, V, Ty, V->getName(), IP);
+ rememberInstruction(CI);
+ return CI;
}
/// InsertBinop - Insert the specified binary operator, doing a small amount
/// of work to avoid inserting an obviously redundant operation.
-Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS,
- Value *RHS, Instruction *&InsertPt) {
+Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode,
+ Value *LHS, Value *RHS) {
// Fold a binop with constant operands.
if (Constant *CLHS = dyn_cast<Constant>(LHS))
if (Constant *CRHS = dyn_cast<Constant>(RHS))
// Do a quick scan to see if we have this binop nearby. If so, reuse it.
unsigned ScanLimit = 6;
- for (BasicBlock::iterator IP = InsertPt, E = InsertPt->getParent()->begin();
- ScanLimit; --IP, --ScanLimit) {
- if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(IP))
- if (BinOp->getOpcode() == Opcode && BinOp->getOperand(0) == LHS &&
- BinOp->getOperand(1) == RHS) {
- // If we found the instruction *at* the insert point, insert later
- // instructions after it.
- if (BinOp == InsertPt)
- InsertPt = ++IP;
- return BinOp;
+ BasicBlock::iterator BlockBegin = Builder.GetInsertBlock()->begin();
+ // Scanning starts from the last instruction before the insertion point.
+ BasicBlock::iterator IP = Builder.GetInsertPoint();
+ if (IP != BlockBegin) {
+ --IP;
+ for (; ScanLimit; --IP, --ScanLimit) {
+ if (IP->getOpcode() == (unsigned)Opcode && IP->getOperand(0) == LHS &&
+ IP->getOperand(1) == RHS)
+ return IP;
+ if (IP == BlockBegin) break;
+ }
+ }
+
+ // If we haven't found this binop, insert it.
+ Value *BO = Builder.CreateBinOp(Opcode, LHS, RHS, "tmp");
+ rememberInstruction(BO);
+ return BO;
+}
+
+/// FactorOutConstant - Test if S is divisible by Factor, using signed
+/// division. If so, update S with Factor divided out and return true.
+/// S need not be evenly divisble if a reasonable remainder can be
+/// computed.
+/// TODO: When ScalarEvolution gets a SCEVSDivExpr, this can be made
+/// unnecessary; in its place, just signed-divide Ops[i] by the scale and
+/// check to see if the divide was folded.
+static bool FactorOutConstant(const SCEV *&S,
+ const SCEV *&Remainder,
+ const SCEV *Factor,
+ ScalarEvolution &SE,
+ const TargetData *TD) {
+ // Everything is divisible by one.
+ if (Factor->isOne())
+ return true;
+
+ // x/x == 1.
+ if (S == Factor) {
+ S = SE.getIntegerSCEV(1, S->getType());
+ return true;
+ }
+
+ // For a Constant, check for a multiple of the given factor.
+ if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S)) {
+ // 0/x == 0.
+ if (C->isZero())
+ return true;
+ // Check for divisibility.
+ if (const SCEVConstant *FC = dyn_cast<SCEVConstant>(Factor)) {
+ ConstantInt *CI =
+ ConstantInt::get(SE.getContext(),
+ C->getValue()->getValue().sdiv(
+ FC->getValue()->getValue()));
+ // If the quotient is zero and the remainder is non-zero, reject
+ // the value at this scale. It will be considered for subsequent
+ // smaller scales.
+ if (!CI->isZero()) {
+ const SCEV *Div = SE.getConstant(CI);
+ S = Div;
+ Remainder =
+ SE.getAddExpr(Remainder,
+ SE.getConstant(C->getValue()->getValue().srem(
+ FC->getValue()->getValue())));
+ return true;
+ }
+ }
+ }
+
+ // In a Mul, check if there is a constant operand which is a multiple
+ // of the given factor.
+ if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S)) {
+ if (TD) {
+ // With TargetData, the size is known. Check if there is a constant
+ // operand which is a multiple of the given factor. If so, we can
+ // factor it.
+ const SCEVConstant *FC = cast<SCEVConstant>(Factor);
+ if (const SCEVConstant *C = dyn_cast<SCEVConstant>(M->getOperand(0)))
+ if (!C->getValue()->getValue().srem(FC->getValue()->getValue())) {
+ const SmallVectorImpl<const SCEV *> &MOperands = M->getOperands();
+ SmallVector<const SCEV *, 4> NewMulOps(MOperands.begin(),
+ MOperands.end());
+ NewMulOps[0] =
+ SE.getConstant(C->getValue()->getValue().sdiv(
+ FC->getValue()->getValue()));
+ S = SE.getMulExpr(NewMulOps);
+ return true;
+ }
+ } else {
+ // Without TargetData, check if Factor can be factored out of any of the
+ // Mul's operands. If so, we can just remove it.
+ for (unsigned i = 0, e = M->getNumOperands(); i != e; ++i) {
+ const SCEV *SOp = M->getOperand(i);
+ const SCEV *Remainder = SE.getIntegerSCEV(0, SOp->getType());
+ if (FactorOutConstant(SOp, Remainder, Factor, SE, TD) &&
+ Remainder->isZero()) {
+ const SmallVectorImpl<const SCEV *> &MOperands = M->getOperands();
+ SmallVector<const SCEV *, 4> NewMulOps(MOperands.begin(),
+ MOperands.end());
+ NewMulOps[i] = SOp;
+ S = SE.getMulExpr(NewMulOps);
+ return true;
+ }
+ }
+ }
+ }
+
+ // In an AddRec, check if both start and step are divisible.
+ if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(S)) {
+ const SCEV *Step = A->getStepRecurrence(SE);
+ const SCEV *StepRem = SE.getIntegerSCEV(0, Step->getType());
+ if (!FactorOutConstant(Step, StepRem, Factor, SE, TD))
+ return false;
+ if (!StepRem->isZero())
+ return false;
+ const SCEV *Start = A->getStart();
+ if (!FactorOutConstant(Start, Remainder, Factor, SE, TD))
+ return false;
+ S = SE.getAddRecExpr(Start, Step, A->getLoop());
+ return true;
+ }
+
+ return false;
+}
+
+/// SimplifyAddOperands - Sort and simplify a list of add operands. NumAddRecs
+/// is the number of SCEVAddRecExprs present, which are kept at the end of
+/// the list.
+///
+static void SimplifyAddOperands(SmallVectorImpl<const SCEV *> &Ops,
+ const Type *Ty,
+ ScalarEvolution &SE) {
+ unsigned NumAddRecs = 0;
+ for (unsigned i = Ops.size(); i > 0 && isa<SCEVAddRecExpr>(Ops[i-1]); --i)
+ ++NumAddRecs;
+ // Group Ops into non-addrecs and addrecs.
+ SmallVector<const SCEV *, 8> NoAddRecs(Ops.begin(), Ops.end() - NumAddRecs);
+ SmallVector<const SCEV *, 8> AddRecs(Ops.end() - NumAddRecs, Ops.end());
+ // Let ScalarEvolution sort and simplify the non-addrecs list.
+ const SCEV *Sum = NoAddRecs.empty() ?
+ SE.getIntegerSCEV(0, Ty) :
+ SE.getAddExpr(NoAddRecs);
+ // If it returned an add, use the operands. Otherwise it simplified
+ // the sum into a single value, so just use that.
+ if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Sum))
+ Ops = Add->getOperands();
+ else {
+ Ops.clear();
+ if (!Sum->isZero())
+ Ops.push_back(Sum);
+ }
+ // Then append the addrecs.
+ Ops.insert(Ops.end(), AddRecs.begin(), AddRecs.end());
+}
+
+/// SplitAddRecs - Flatten a list of add operands, moving addrec start values
+/// out to the top level. For example, convert {a + b,+,c} to a, b, {0,+,d}.
+/// This helps expose more opportunities for folding parts of the expressions
+/// into GEP indices.
+///
+static void SplitAddRecs(SmallVectorImpl<const SCEV *> &Ops,
+ const Type *Ty,
+ ScalarEvolution &SE) {
+ // Find the addrecs.
+ SmallVector<const SCEV *, 8> AddRecs;
+ for (unsigned i = 0, e = Ops.size(); i != e; ++i)
+ while (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(Ops[i])) {
+ const SCEV *Start = A->getStart();
+ if (Start->isZero()) break;
+ const SCEV *Zero = SE.getIntegerSCEV(0, Ty);
+ AddRecs.push_back(SE.getAddRecExpr(Zero,
+ A->getStepRecurrence(SE),
+ A->getLoop()));
+ if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Start)) {
+ Ops[i] = Zero;
+ Ops.insert(Ops.end(), Add->op_begin(), Add->op_end());
+ e += Add->getNumOperands();
+ } else {
+ Ops[i] = Start;
+ }
+ }
+ if (!AddRecs.empty()) {
+ // Add the addrecs onto the end of the list.
+ Ops.insert(Ops.end(), AddRecs.begin(), AddRecs.end());
+ // Resort the operand list, moving any constants to the front.
+ SimplifyAddOperands(Ops, Ty, SE);
+ }
+}
+
+/// expandAddToGEP - Expand an addition expression with a pointer type into
+/// a GEP instead of using ptrtoint+arithmetic+inttoptr. This helps
+/// BasicAliasAnalysis and other passes analyze the result. See the rules
+/// for getelementptr vs. inttoptr in
+/// http://llvm.org/docs/LangRef.html#pointeraliasing
+/// for details.
+///
+/// Design note: The correctness of using getelementptr here depends on
+/// ScalarEvolution not recognizing inttoptr and ptrtoint operators, as
+/// they may introduce pointer arithmetic which may not be safely converted
+/// into getelementptr.
+///
+/// Design note: It might seem desirable for this function to be more
+/// loop-aware. If some of the indices are loop-invariant while others
+/// aren't, it might seem desirable to emit multiple GEPs, keeping the
+/// loop-invariant portions of the overall computation outside the loop.
+/// However, there are a few reasons this is not done here. Hoisting simple
+/// arithmetic is a low-level optimization that often isn't very
+/// important until late in the optimization process. In fact, passes
+/// like InstructionCombining will combine GEPs, even if it means
+/// pushing loop-invariant computation down into loops, so even if the
+/// GEPs were split here, the work would quickly be undone. The
+/// LoopStrengthReduction pass, which is usually run quite late (and
+/// after the last InstructionCombining pass), takes care of hoisting
+/// loop-invariant portions of expressions, after considering what
+/// can be folded using target addressing modes.
+///
+Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
+ const SCEV *const *op_end,
+ const PointerType *PTy,
+ const Type *Ty,
+ Value *V) {
+ const Type *ElTy = PTy->getElementType();
+ SmallVector<Value *, 4> GepIndices;
+ SmallVector<const SCEV *, 8> Ops(op_begin, op_end);
+ bool AnyNonZeroIndices = false;
+
+ // Split AddRecs up into parts as either of the parts may be usable
+ // without the other.
+ SplitAddRecs(Ops, Ty, SE);
+
+ // Descend down the pointer's type and attempt to convert the other
+ // operands into GEP indices, at each level. The first index in a GEP
+ // indexes into the array implied by the pointer operand; the rest of
+ // the indices index into the element or field type selected by the
+ // preceding index.
+ for (;;) {
+ // If the scale size is not 0, attempt to factor out a scale for
+ // array indexing.
+ SmallVector<const SCEV *, 8> ScaledOps;
+ if (ElTy->isSized()) {
+ const SCEV *ElSize = SE.getSizeOfExpr(ElTy);
+ if (!ElSize->isZero()) {
+ SmallVector<const SCEV *, 8> NewOps;
+ for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
+ const SCEV *Op = Ops[i];
+ const SCEV *Remainder = SE.getIntegerSCEV(0, Ty);
+ if (FactorOutConstant(Op, Remainder, ElSize, SE, SE.TD)) {
+ // Op now has ElSize factored out.
+ ScaledOps.push_back(Op);
+ if (!Remainder->isZero())
+ NewOps.push_back(Remainder);
+ AnyNonZeroIndices = true;
+ } else {
+ // The operand was not divisible, so add it to the list of operands
+ // we'll scan next iteration.
+ NewOps.push_back(Ops[i]);
+ }
+ }
+ // If we made any changes, update Ops.
+ if (!ScaledOps.empty()) {
+ Ops = NewOps;
+ SimplifyAddOperands(Ops, Ty, SE);
+ }
+ }
+ }
+
+ // Record the scaled array index for this level of the type. If
+ // we didn't find any operands that could be factored, tentatively
+ // assume that element zero was selected (since the zero offset
+ // would obviously be folded away).
+ Value *Scaled = ScaledOps.empty() ?
+ Constant::getNullValue(Ty) :
+ expandCodeFor(SE.getAddExpr(ScaledOps), Ty);
+ GepIndices.push_back(Scaled);
+
+ // Collect struct field index operands.
+ while (const StructType *STy = dyn_cast<StructType>(ElTy)) {
+ bool FoundFieldNo = false;
+ // An empty struct has no fields.
+ if (STy->getNumElements() == 0) break;
+ if (SE.TD) {
+ // With TargetData, field offsets are known. See if a constant offset
+ // falls within any of the struct fields.
+ if (Ops.empty()) break;
+ if (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[0]))
+ if (SE.getTypeSizeInBits(C->getType()) <= 64) {
+ const StructLayout &SL = *SE.TD->getStructLayout(STy);
+ uint64_t FullOffset = C->getValue()->getZExtValue();
+ if (FullOffset < SL.getSizeInBytes()) {
+ unsigned ElIdx = SL.getElementContainingOffset(FullOffset);
+ GepIndices.push_back(
+ ConstantInt::get(Type::getInt32Ty(Ty->getContext()), ElIdx));
+ ElTy = STy->getTypeAtIndex(ElIdx);
+ Ops[0] =
+ SE.getConstant(Ty, FullOffset - SL.getElementOffset(ElIdx));
+ AnyNonZeroIndices = true;
+ FoundFieldNo = true;
+ }
+ }
+ } else {
+ // Without TargetData, just check for an offsetof expression of the
+ // appropriate struct type.
+ for (unsigned i = 0, e = Ops.size(); i != e; ++i)
+ if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(Ops[i])) {
+ const Type *CTy;
+ Constant *FieldNo;
+ if (U->isOffsetOf(CTy, FieldNo) && CTy == STy) {
+ GepIndices.push_back(FieldNo);
+ ElTy =
+ STy->getTypeAtIndex(cast<ConstantInt>(FieldNo)->getZExtValue());
+ Ops[i] = SE.getConstant(Ty, 0);
+ AnyNonZeroIndices = true;
+ FoundFieldNo = true;
+ break;
+ }
+ }
}
- if (IP == E) break;
+ // If no struct field offsets were found, tentatively assume that
+ // field zero was selected (since the zero offset would obviously
+ // be folded away).
+ if (!FoundFieldNo) {
+ ElTy = STy->getTypeAtIndex(0u);
+ GepIndices.push_back(
+ Constant::getNullValue(Type::getInt32Ty(Ty->getContext())));
+ }
+ }
+
+ if (const ArrayType *ATy = dyn_cast<ArrayType>(ElTy))
+ ElTy = ATy->getElementType();
+ else
+ break;
+ }
+
+ // If none of the operands were convertable to proper GEP indices, cast
+ // the base to i8* and do an ugly getelementptr with that. It's still
+ // better than ptrtoint+arithmetic+inttoptr at least.
+ if (!AnyNonZeroIndices) {
+ // Cast the base to i8*.
+ V = InsertNoopCastOfTo(V,
+ Type::getInt8PtrTy(Ty->getContext(), PTy->getAddressSpace()));
+
+ // Expand the operands for a plain byte offset.
+ Value *Idx = expandCodeFor(SE.getAddExpr(Ops), Ty);
+
+ // Fold a GEP with constant operands.
+ if (Constant *CLHS = dyn_cast<Constant>(V))
+ if (Constant *CRHS = dyn_cast<Constant>(Idx))
+ return ConstantExpr::getGetElementPtr(CLHS, &CRHS, 1);
+
+ // Do a quick scan to see if we have this GEP nearby. If so, reuse it.
+ unsigned ScanLimit = 6;
+ BasicBlock::iterator BlockBegin = Builder.GetInsertBlock()->begin();
+ // Scanning starts from the last instruction before the insertion point.
+ BasicBlock::iterator IP = Builder.GetInsertPoint();
+ if (IP != BlockBegin) {
+ --IP;
+ for (; ScanLimit; --IP, --ScanLimit) {
+ if (IP->getOpcode() == Instruction::GetElementPtr &&
+ IP->getOperand(0) == V && IP->getOperand(1) == Idx)
+ return IP;
+ if (IP == BlockBegin) break;
+ }
+ }
+
+ // Emit a GEP.
+ Value *GEP = Builder.CreateGEP(V, Idx, "uglygep");
+ rememberInstruction(GEP);
+ return GEP;
}
- // If we don't have
- return BinaryOperator::create(Opcode, LHS, RHS, "tmp.", InsertPt);
+ // Insert a pretty getelementptr. Note that this GEP is not marked inbounds,
+ // because ScalarEvolution may have changed the address arithmetic to
+ // compute a value which is beyond the end of the allocated object.
+ Value *Casted = V;
+ if (V->getType() != PTy)
+ Casted = InsertNoopCastOfTo(Casted, PTy);
+ Value *GEP = Builder.CreateGEP(Casted,
+ GepIndices.begin(),
+ GepIndices.end(),
+ "scevgep");
+ Ops.push_back(SE.getUnknown(GEP));
+ rememberInstruction(GEP);
+ return expand(SE.getAddExpr(Ops));
}
-Value *SCEVExpander::visitMulExpr(SCEVMulExpr *S) {
+/// isNonConstantNegative - Return true if the specified scev is negated, but
+/// not a constant.
+static bool isNonConstantNegative(const SCEV *F) {
+ const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(F);
+ if (!Mul) return false;
+
+ // If there is a constant factor, it will be first.
+ const SCEVConstant *SC = dyn_cast<SCEVConstant>(Mul->getOperand(0));
+ if (!SC) return false;
+
+ // Return true if the value is negative, this matches things like (-42 * V).
+ return SC->getValue()->getValue().isNegative();
+}
+
+Value *SCEVExpander::visitAddExpr(const SCEVAddExpr *S) {
+ int NumOperands = S->getNumOperands();
+ const Type *Ty = SE.getEffectiveSCEVType(S->getType());
+
+ // Find the index of an operand to start with. Choose the operand with
+ // pointer type, if there is one, or the last operand otherwise.
+ int PIdx = 0;
+ for (; PIdx != NumOperands - 1; ++PIdx)
+ if (isa<PointerType>(S->getOperand(PIdx)->getType())) break;
+
+ // Expand code for the operand that we chose.
+ Value *V = expand(S->getOperand(PIdx));
+
+ // Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the
+ // comments on expandAddToGEP for details.
+ if (const PointerType *PTy = dyn_cast<PointerType>(V->getType())) {
+ // Take the operand at PIdx out of the list.
+ const SmallVectorImpl<const SCEV *> &Ops = S->getOperands();
+ SmallVector<const SCEV *, 8> NewOps;
+ NewOps.insert(NewOps.end(), Ops.begin(), Ops.begin() + PIdx);
+ NewOps.insert(NewOps.end(), Ops.begin() + PIdx + 1, Ops.end());
+ // Make a GEP.
+ return expandAddToGEP(NewOps.begin(), NewOps.end(), PTy, Ty, V);
+ }
+
+ // Otherwise, we'll expand the rest of the SCEVAddExpr as plain integer
+ // arithmetic.
+ V = InsertNoopCastOfTo(V, Ty);
+
+ // Emit a bunch of add instructions
+ for (int i = NumOperands-1; i >= 0; --i) {
+ if (i == PIdx) continue;
+ const SCEV *Op = S->getOperand(i);
+ if (isNonConstantNegative(Op)) {
+ Value *W = expandCodeFor(SE.getNegativeSCEV(Op), Ty);
+ V = InsertBinop(Instruction::Sub, V, W);
+ } else {
+ Value *W = expandCodeFor(Op, Ty);
+ V = InsertBinop(Instruction::Add, V, W);
+ }
+ }
+ return V;
+}
+
+Value *SCEVExpander::visitMulExpr(const SCEVMulExpr *S) {
+ const Type *Ty = SE.getEffectiveSCEVType(S->getType());
int FirstOp = 0; // Set if we should emit a subtract.
- if (SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getOperand(0)))
+ if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getOperand(0)))
if (SC->getValue()->isAllOnesValue())
FirstOp = 1;
int i = S->getNumOperands()-2;
- Value *V = expand(S->getOperand(i+1));
+ Value *V = expandCodeFor(S->getOperand(i+1), Ty);
// Emit a bunch of multiply instructions
- for (; i >= FirstOp; --i)
- V = InsertBinop(Instruction::Mul, V, expand(S->getOperand(i)),
- InsertPt);
+ for (; i >= FirstOp; --i) {
+ Value *W = expandCodeFor(S->getOperand(i), Ty);
+ V = InsertBinop(Instruction::Mul, V, W);
+ }
+
// -1 * ... ---> 0 - ...
if (FirstOp == 1)
- V = InsertBinop(Instruction::Sub, Constant::getNullValue(V->getType()), V,
- InsertPt);
+ V = InsertBinop(Instruction::Sub, Constant::getNullValue(Ty), V);
return V;
}
-Value *SCEVExpander::visitAddRecExpr(SCEVAddRecExpr *S) {
- const Type *Ty = S->getType();
+Value *SCEVExpander::visitUDivExpr(const SCEVUDivExpr *S) {
+ const Type *Ty = SE.getEffectiveSCEVType(S->getType());
+
+ Value *LHS = expandCodeFor(S->getLHS(), Ty);
+ if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getRHS())) {
+ const APInt &RHS = SC->getValue()->getValue();
+ if (RHS.isPowerOf2())
+ return InsertBinop(Instruction::LShr, LHS,
+ ConstantInt::get(Ty, RHS.logBase2()));
+ }
+
+ Value *RHS = expandCodeFor(S->getRHS(), Ty);
+ return InsertBinop(Instruction::UDiv, LHS, RHS);
+}
+
+/// Move parts of Base into Rest to leave Base with the minimal
+/// expression that provides a pointer operand suitable for a
+/// GEP expansion.
+static void ExposePointerBase(const SCEV *&Base, const SCEV *&Rest,
+ ScalarEvolution &SE) {
+ while (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(Base)) {
+ Base = A->getStart();
+ Rest = SE.getAddExpr(Rest,
+ SE.getAddRecExpr(SE.getIntegerSCEV(0, A->getType()),
+ A->getStepRecurrence(SE),
+ A->getLoop()));
+ }
+ if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(Base)) {
+ Base = A->getOperand(A->getNumOperands()-1);
+ SmallVector<const SCEV *, 8> NewAddOps(A->op_begin(), A->op_end());
+ NewAddOps.back() = Rest;
+ Rest = SE.getAddExpr(NewAddOps);
+ ExposePointerBase(Base, Rest, SE);
+ }
+}
+
+/// getAddRecExprPHILiterally - Helper for expandAddRecExprLiterally. Expand
+/// the base addrec, which is the addrec without any non-loop-dominating
+/// values, and return the PHI.
+PHINode *
+SCEVExpander::getAddRecExprPHILiterally(const SCEVAddRecExpr *Normalized,
+ const Loop *L,
+ const Type *ExpandTy,
+ const Type *IntTy) {
+ // Reuse a previously-inserted PHI, if present.
+ for (BasicBlock::iterator I = L->getHeader()->begin();
+ PHINode *PN = dyn_cast<PHINode>(I); ++I)
+ if (SE.isSCEVable(PN->getType()) &&
+ (SE.getEffectiveSCEVType(PN->getType()) ==
+ SE.getEffectiveSCEVType(Normalized->getType())) &&
+ SE.getSCEV(PN) == Normalized)
+ if (BasicBlock *LatchBlock = L->getLoopLatch()) {
+ // Remember this PHI, even in post-inc mode.
+ InsertedValues.insert(PN);
+ // Remember the increment.
+ Instruction *IncV =
+ cast<Instruction>(PN->getIncomingValueForBlock(LatchBlock)
+ ->stripPointerCasts());
+ rememberInstruction(IncV);
+ // Make sure the increment is where we want it. But don't move it
+ // down past a potential existing post-inc user.
+ if (L == IVIncInsertLoop && !SE.DT->dominates(IncV, IVIncInsertPos))
+ IncV->moveBefore(IVIncInsertPos);
+ return PN;
+ }
+
+ // Save the original insertion point so we can restore it when we're done.
+ BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
+ BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+
+ // Expand code for the start value.
+ Value *StartV = expandCodeFor(Normalized->getStart(), ExpandTy,
+ L->getHeader()->begin());
+
+ // Expand code for the step value. Insert instructions right before the
+ // terminator corresponding to the back-edge. Do this before creating the PHI
+ // so that PHI reuse code doesn't see an incomplete PHI. If the stride is
+ // negative, insert a sub instead of an add for the increment (unless it's a
+ // constant, because subtracts of constants are canonicalized to adds).
+ const SCEV *Step = Normalized->getStepRecurrence(SE);
+ bool isPointer = isa<PointerType>(ExpandTy);
+ bool isNegative = !isPointer && isNonConstantNegative(Step);
+ if (isNegative)
+ Step = SE.getNegativeSCEV(Step);
+ Value *StepV = expandCodeFor(Step, IntTy, L->getHeader()->begin());
+
+ // Create the PHI.
+ Builder.SetInsertPoint(L->getHeader(), L->getHeader()->begin());
+ PHINode *PN = Builder.CreatePHI(ExpandTy, "lsr.iv");
+ rememberInstruction(PN);
+
+ // Create the step instructions and populate the PHI.
+ BasicBlock *Header = L->getHeader();
+ for (pred_iterator HPI = pred_begin(Header), HPE = pred_end(Header);
+ HPI != HPE; ++HPI) {
+ BasicBlock *Pred = *HPI;
+
+ // Add a start value.
+ if (!L->contains(Pred)) {
+ PN->addIncoming(StartV, Pred);
+ continue;
+ }
+
+ // Create a step value and add it to the PHI. If IVIncInsertLoop is
+ // non-null and equal to the addrec's loop, insert the instructions
+ // at IVIncInsertPos.
+ Instruction *InsertPos = L == IVIncInsertLoop ?
+ IVIncInsertPos : Pred->getTerminator();
+ Builder.SetInsertPoint(InsertPos->getParent(), InsertPos);
+ Value *IncV;
+ // If the PHI is a pointer, use a GEP, otherwise use an add or sub.
+ if (isPointer) {
+ const PointerType *GEPPtrTy = cast<PointerType>(ExpandTy);
+ // If the step isn't constant, don't use an implicitly scaled GEP, because
+ // that would require a multiply inside the loop.
+ if (!isa<ConstantInt>(StepV))
+ GEPPtrTy = PointerType::get(Type::getInt1Ty(SE.getContext()),
+ GEPPtrTy->getAddressSpace());
+ const SCEV *const StepArray[1] = { SE.getSCEV(StepV) };
+ IncV = expandAddToGEP(StepArray, StepArray+1, GEPPtrTy, IntTy, PN);
+ if (IncV->getType() != PN->getType()) {
+ IncV = Builder.CreateBitCast(IncV, PN->getType(), "tmp");
+ rememberInstruction(IncV);
+ }
+ } else {
+ IncV = isNegative ?
+ Builder.CreateSub(PN, StepV, "lsr.iv.next") :
+ Builder.CreateAdd(PN, StepV, "lsr.iv.next");
+ rememberInstruction(IncV);
+ }
+ PN->addIncoming(IncV, Pred);
+ }
+
+ // Restore the original insert point.
+ if (SaveInsertBB)
+ restoreInsertPoint(SaveInsertBB, SaveInsertPt);
+
+ // Remember this PHI, even in post-inc mode.
+ InsertedValues.insert(PN);
+
+ return PN;
+}
+
+Value *SCEVExpander::expandAddRecExprLiterally(const SCEVAddRecExpr *S) {
+ const Type *STy = S->getType();
+ const Type *IntTy = SE.getEffectiveSCEVType(STy);
+ const Loop *L = S->getLoop();
+
+ // Determine a normalized form of this expression, which is the expression
+ // before any post-inc adjustment is made.
+ const SCEVAddRecExpr *Normalized = S;
+ if (L == PostIncLoop) {
+ const SCEV *Step = S->getStepRecurrence(SE);
+ Normalized = cast<SCEVAddRecExpr>(SE.getMinusSCEV(S, Step));
+ }
+
+ // Strip off any non-loop-dominating component from the addrec start.
+ const SCEV *Start = Normalized->getStart();
+ const SCEV *PostLoopOffset = 0;
+ if (!Start->properlyDominates(L->getHeader(), SE.DT)) {
+ PostLoopOffset = Start;
+ Start = SE.getIntegerSCEV(0, Normalized->getType());
+ Normalized =
+ cast<SCEVAddRecExpr>(SE.getAddRecExpr(Start,
+ Normalized->getStepRecurrence(SE),
+ Normalized->getLoop()));
+ }
+
+ // Strip off any non-loop-dominating component from the addrec step.
+ const SCEV *Step = Normalized->getStepRecurrence(SE);
+ const SCEV *PostLoopScale = 0;
+ if (!Step->hasComputableLoopEvolution(L) &&
+ !Step->dominates(L->getHeader(), SE.DT)) {
+ PostLoopScale = Step;
+ Step = SE.getIntegerSCEV(1, Normalized->getType());
+ Normalized =
+ cast<SCEVAddRecExpr>(SE.getAddRecExpr(Start, Step,
+ Normalized->getLoop()));
+ }
+
+ // Expand the core addrec. If we need post-loop scaling, force it to
+ // expand to an integer type to avoid the need for additional casting.
+ const Type *ExpandTy = PostLoopScale ? IntTy : STy;
+ PHINode *PN = getAddRecExprPHILiterally(Normalized, L, ExpandTy, IntTy);
+
+ // Accomodate post-inc mode, if necessary.
+ Value *Result;
+ if (L != PostIncLoop)
+ Result = PN;
+ else {
+ // In PostInc mode, use the post-incremented value.
+ BasicBlock *LatchBlock = L->getLoopLatch();
+ assert(LatchBlock && "PostInc mode requires a unique loop latch!");
+ Result = PN->getIncomingValueForBlock(LatchBlock);
+ }
+
+ // Re-apply any non-loop-dominating scale.
+ if (PostLoopScale) {
+ Result = InsertNoopCastOfTo(Result, IntTy);
+ Result = Builder.CreateMul(Result,
+ expandCodeFor(PostLoopScale, IntTy));
+ rememberInstruction(Result);
+ }
+
+ // Re-apply any non-loop-dominating offset.
+ if (PostLoopOffset) {
+ if (const PointerType *PTy = dyn_cast<PointerType>(ExpandTy)) {
+ const SCEV *const OffsetArray[1] = { PostLoopOffset };
+ Result = expandAddToGEP(OffsetArray, OffsetArray+1, PTy, IntTy, Result);
+ } else {
+ Result = InsertNoopCastOfTo(Result, IntTy);
+ Result = Builder.CreateAdd(Result,
+ expandCodeFor(PostLoopOffset, IntTy));
+ rememberInstruction(Result);
+ }
+ }
+
+ return Result;
+}
+
+Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
+ if (!CanonicalMode) return expandAddRecExprLiterally(S);
+
+ const Type *Ty = SE.getEffectiveSCEVType(S->getType());
const Loop *L = S->getLoop();
- // We cannot yet do fp recurrences, e.g. the xform of {X,+,F} --> X+{0,+,F}
- assert(Ty->isInteger() && "Cannot expand fp recurrences yet!");
+
+ // First check for an existing canonical IV in a suitable type.
+ PHINode *CanonicalIV = 0;
+ if (PHINode *PN = L->getCanonicalInductionVariable())
+ if (SE.isSCEVable(PN->getType()) &&
+ isa<IntegerType>(SE.getEffectiveSCEVType(PN->getType())) &&
+ SE.getTypeSizeInBits(PN->getType()) >= SE.getTypeSizeInBits(Ty))
+ CanonicalIV = PN;
+
+ // Rewrite an AddRec in terms of the canonical induction variable, if
+ // its type is more narrow.
+ if (CanonicalIV &&
+ SE.getTypeSizeInBits(CanonicalIV->getType()) >
+ SE.getTypeSizeInBits(Ty)) {
+ const SmallVectorImpl<const SCEV *> &Ops = S->getOperands();
+ SmallVector<const SCEV *, 4> NewOps(Ops.size());
+ for (unsigned i = 0, e = Ops.size(); i != e; ++i)
+ NewOps[i] = SE.getAnyExtendExpr(Ops[i], CanonicalIV->getType());
+ Value *V = expand(SE.getAddRecExpr(NewOps, S->getLoop()));
+ BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
+ BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+ BasicBlock::iterator NewInsertPt =
+ llvm::next(BasicBlock::iterator(cast<Instruction>(V)));
+ while (isa<PHINode>(NewInsertPt)) ++NewInsertPt;
+ V = expandCodeFor(SE.getTruncateExpr(SE.getUnknown(V), Ty), 0,
+ NewInsertPt);
+ restoreInsertPoint(SaveInsertBB, SaveInsertPt);
+ return V;
+ }
// {X,+,F} --> X + {0,+,F}
- if (!isa<SCEVConstant>(S->getStart()) ||
- !cast<SCEVConstant>(S->getStart())->getValue()->isZero()) {
- Value *Start = expand(S->getStart());
- std::vector<SCEVHandle> NewOps(S->op_begin(), S->op_end());
- NewOps[0] = SCEVUnknown::getIntegerSCEV(0, Ty);
- Value *Rest = expand(SCEVAddRecExpr::get(NewOps, L));
+ if (!S->getStart()->isZero()) {
+ const SmallVectorImpl<const SCEV *> &SOperands = S->getOperands();
+ SmallVector<const SCEV *, 4> NewOps(SOperands.begin(), SOperands.end());
+ NewOps[0] = SE.getIntegerSCEV(0, Ty);
+ const SCEV *Rest = SE.getAddRecExpr(NewOps, L);
+
+ // Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the
+ // comments on expandAddToGEP for details.
+ const SCEV *Base = S->getStart();
+ const SCEV *RestArray[1] = { Rest };
+ // Dig into the expression to find the pointer base for a GEP.
+ ExposePointerBase(Base, RestArray[0], SE);
+ // If we found a pointer, expand the AddRec with a GEP.
+ if (const PointerType *PTy = dyn_cast<PointerType>(Base->getType())) {
+ // Make sure the Base isn't something exotic, such as a multiplied
+ // or divided pointer value. In those cases, the result type isn't
+ // actually a pointer type.
+ if (!isa<SCEVMulExpr>(Base) && !isa<SCEVUDivExpr>(Base)) {
+ Value *StartV = expand(Base);
+ assert(StartV->getType() == PTy && "Pointer type mismatch for GEP!");
+ return expandAddToGEP(RestArray, RestArray+1, PTy, Ty, StartV);
+ }
+ }
- // FIXME: look for an existing add to use.
- return InsertBinop(Instruction::Add, Rest, Start, InsertPt);
+ // Just do a normal add. Pre-expand the operands to suppress folding.
+ return expand(SE.getAddExpr(SE.getUnknown(expand(S->getStart())),
+ SE.getUnknown(expand(Rest))));
}
// {0,+,1} --> Insert a canonical induction variable into the loop!
- if (S->getNumOperands() == 2 &&
- S->getOperand(1) == SCEVUnknown::getIntegerSCEV(1, Ty)) {
+ if (S->isAffine() &&
+ S->getOperand(1) == SE.getIntegerSCEV(1, Ty)) {
+ // If there's a canonical IV, just use it.
+ if (CanonicalIV) {
+ assert(Ty == SE.getEffectiveSCEVType(CanonicalIV->getType()) &&
+ "IVs with types different from the canonical IV should "
+ "already have been handled!");
+ return CanonicalIV;
+ }
+
// Create and insert the PHI node for the induction variable in the
// specified loop.
BasicBlock *Header = L->getHeader();
- PHINode *PN = new PHINode(Ty, "indvar", Header->begin());
- PN->addIncoming(Constant::getNullValue(Ty), L->getLoopPreheader());
-
- pred_iterator HPI = pred_begin(Header);
- assert(HPI != pred_end(Header) && "Loop with zero preds???");
- if (!L->contains(*HPI)) ++HPI;
- assert(HPI != pred_end(Header) && L->contains(*HPI) &&
- "No backedge in loop?");
+ PHINode *PN = PHINode::Create(Ty, "indvar", Header->begin());
+ rememberInstruction(PN);
- // Insert a unit add instruction right before the terminator corresponding
- // to the back-edge.
Constant *One = ConstantInt::get(Ty, 1);
- Instruction *Add = BinaryOperator::createAdd(PN, One, "indvar.next",
- (*HPI)->getTerminator());
-
- pred_iterator PI = pred_begin(Header);
- if (*PI == L->getLoopPreheader())
- ++PI;
- PN->addIncoming(Add, *PI);
- return PN;
+ for (pred_iterator HPI = pred_begin(Header), HPE = pred_end(Header);
+ HPI != HPE; ++HPI)
+ if (L->contains(*HPI)) {
+ // Insert a unit add instruction right before the terminator
+ // corresponding to the back-edge.
+ Instruction *Add = BinaryOperator::CreateAdd(PN, One, "indvar.next",
+ (*HPI)->getTerminator());
+ rememberInstruction(Add);
+ PN->addIncoming(Add, *HPI);
+ } else {
+ PN->addIncoming(Constant::getNullValue(Ty), *HPI);
+ }
}
+ // {0,+,F} --> {0,+,1} * F
// Get the canonical induction variable I for this loop.
- Value *I = getOrInsertCanonicalInductionVariable(L, Ty);
+ Value *I = CanonicalIV ?
+ CanonicalIV :
+ getOrInsertCanonicalInductionVariable(L, Ty);
// If this is a simple linear addrec, emit it now as a special case.
- if (S->getNumOperands() == 2) { // {0,+,F} --> i*F
- Value *F = expand(S->getOperand(1));
-
- // IF the step is by one, just return the inserted IV.
- if (ConstantInt *CI = dyn_cast<ConstantInt>(F))
- if (CI->getValue() == 1)
- return I;
-
- // If the insert point is directly inside of the loop, emit the multiply at
- // the insert point. Otherwise, L is a loop that is a parent of the insert
- // point loop. If we can, move the multiply to the outer most loop that it
- // is safe to be in.
- Instruction *MulInsertPt = InsertPt;
- Loop *InsertPtLoop = LI.getLoopFor(MulInsertPt->getParent());
- if (InsertPtLoop != L && InsertPtLoop &&
- L->contains(InsertPtLoop->getHeader())) {
- while (InsertPtLoop != L) {
- // If we cannot hoist the multiply out of this loop, don't.
- if (!InsertPtLoop->isLoopInvariant(F)) break;
-
- // Otherwise, move the insert point to the preheader of the loop.
- MulInsertPt = InsertPtLoop->getLoopPreheader()->getTerminator();
- InsertPtLoop = InsertPtLoop->getParentLoop();
- }
- }
-
- return InsertBinop(Instruction::Mul, I, F, MulInsertPt);
- }
+ if (S->isAffine()) // {0,+,F} --> i*F
+ return
+ expand(SE.getTruncateOrNoop(
+ SE.getMulExpr(SE.getUnknown(I),
+ SE.getNoopOrAnyExtend(S->getOperand(1),
+ I->getType())),
+ Ty));
// If this is a chain of recurrences, turn it into a closed form, using the
// folders, then expandCodeFor the closed form. This allows the folders to
// simplify the expression without having to build a bunch of special code
// into this folder.
- SCEVHandle IH = SCEVUnknown::get(I); // Get I as a "symbolic" SCEV.
+ const SCEV *IH = SE.getUnknown(I); // Get I as a "symbolic" SCEV.
+
+ // Promote S up to the canonical IV type, if the cast is foldable.
+ const SCEV *NewS = S;
+ const SCEV *Ext = SE.getNoopOrAnyExtend(S, I->getType());
+ if (isa<SCEVAddRecExpr>(Ext))
+ NewS = Ext;
- SCEVHandle V = S->evaluateAtIteration(IH);
+ const SCEV *V = cast<SCEVAddRecExpr>(NewS)->evaluateAtIteration(IH, SE);
//cerr << "Evaluated: " << *this << "\n to: " << *V << "\n";
- return expand(V);
+ // Truncate the result down to the original type, if needed.
+ const SCEV *T = SE.getTruncateOrNoop(V, Ty);
+ return expand(T);
+}
+
+Value *SCEVExpander::visitTruncateExpr(const SCEVTruncateExpr *S) {
+ const Type *Ty = SE.getEffectiveSCEVType(S->getType());
+ Value *V = expandCodeFor(S->getOperand(),
+ SE.getEffectiveSCEVType(S->getOperand()->getType()));
+ Value *I = Builder.CreateTrunc(V, Ty, "tmp");
+ rememberInstruction(I);
+ return I;
+}
+
+Value *SCEVExpander::visitZeroExtendExpr(const SCEVZeroExtendExpr *S) {
+ const Type *Ty = SE.getEffectiveSCEVType(S->getType());
+ Value *V = expandCodeFor(S->getOperand(),
+ SE.getEffectiveSCEVType(S->getOperand()->getType()));
+ Value *I = Builder.CreateZExt(V, Ty, "tmp");
+ rememberInstruction(I);
+ return I;
+}
+
+Value *SCEVExpander::visitSignExtendExpr(const SCEVSignExtendExpr *S) {
+ const Type *Ty = SE.getEffectiveSCEVType(S->getType());
+ Value *V = expandCodeFor(S->getOperand(),
+ SE.getEffectiveSCEVType(S->getOperand()->getType()));
+ Value *I = Builder.CreateSExt(V, Ty, "tmp");
+ rememberInstruction(I);
+ return I;
+}
+
+Value *SCEVExpander::visitSMaxExpr(const SCEVSMaxExpr *S) {
+ Value *LHS = expand(S->getOperand(S->getNumOperands()-1));
+ const Type *Ty = LHS->getType();
+ for (int i = S->getNumOperands()-2; i >= 0; --i) {
+ // In the case of mixed integer and pointer types, do the
+ // rest of the comparisons as integer.
+ if (S->getOperand(i)->getType() != Ty) {
+ Ty = SE.getEffectiveSCEVType(Ty);
+ LHS = InsertNoopCastOfTo(LHS, Ty);
+ }
+ Value *RHS = expandCodeFor(S->getOperand(i), Ty);
+ Value *ICmp = Builder.CreateICmpSGT(LHS, RHS, "tmp");
+ rememberInstruction(ICmp);
+ Value *Sel = Builder.CreateSelect(ICmp, LHS, RHS, "smax");
+ rememberInstruction(Sel);
+ LHS = Sel;
+ }
+ // In the case of mixed integer and pointer types, cast the
+ // final result back to the pointer type.
+ if (LHS->getType() != S->getType())
+ LHS = InsertNoopCastOfTo(LHS, S->getType());
+ return LHS;
+}
+
+Value *SCEVExpander::visitUMaxExpr(const SCEVUMaxExpr *S) {
+ Value *LHS = expand(S->getOperand(S->getNumOperands()-1));
+ const Type *Ty = LHS->getType();
+ for (int i = S->getNumOperands()-2; i >= 0; --i) {
+ // In the case of mixed integer and pointer types, do the
+ // rest of the comparisons as integer.
+ if (S->getOperand(i)->getType() != Ty) {
+ Ty = SE.getEffectiveSCEVType(Ty);
+ LHS = InsertNoopCastOfTo(LHS, Ty);
+ }
+ Value *RHS = expandCodeFor(S->getOperand(i), Ty);
+ Value *ICmp = Builder.CreateICmpUGT(LHS, RHS, "tmp");
+ rememberInstruction(ICmp);
+ Value *Sel = Builder.CreateSelect(ICmp, LHS, RHS, "umax");
+ rememberInstruction(Sel);
+ LHS = Sel;
+ }
+ // In the case of mixed integer and pointer types, cast the
+ // final result back to the pointer type.
+ if (LHS->getType() != S->getType())
+ LHS = InsertNoopCastOfTo(LHS, S->getType());
+ return LHS;
}
-Value *SCEVExpander::expand(SCEV *S) {
- // Check to see if we already expanded this.
- std::map<SCEVHandle, Value*>::iterator I = InsertedExpressions.find(S);
+Value *SCEVExpander::expandCodeFor(const SCEV *SH, const Type *Ty) {
+ // Expand the code for this SCEV.
+ Value *V = expand(SH);
+ if (Ty) {
+ assert(SE.getTypeSizeInBits(Ty) == SE.getTypeSizeInBits(SH->getType()) &&
+ "non-trivial casts should be done with the SCEVs directly!");
+ V = InsertNoopCastOfTo(V, Ty);
+ }
+ return V;
+}
+
+Value *SCEVExpander::expand(const SCEV *S) {
+ // Compute an insertion point for this SCEV object. Hoist the instructions
+ // as far out in the loop nest as possible.
+ Instruction *InsertPt = Builder.GetInsertPoint();
+ for (Loop *L = SE.LI->getLoopFor(Builder.GetInsertBlock()); ;
+ L = L->getParentLoop())
+ if (S->isLoopInvariant(L)) {
+ if (!L) break;
+ if (BasicBlock *Preheader = L->getLoopPreheader())
+ InsertPt = Preheader->getTerminator();
+ } else {
+ // If the SCEV is computable at this level, insert it into the header
+ // after the PHIs (and after any other instructions that we've inserted
+ // there) so that it is guaranteed to dominate any user inside the loop.
+ if (L && S->hasComputableLoopEvolution(L))
+ InsertPt = L->getHeader()->getFirstNonPHI();
+ while (isInsertedInstruction(InsertPt))
+ InsertPt = llvm::next(BasicBlock::iterator(InsertPt));
+ break;
+ }
+
+ // Check to see if we already expanded this here.
+ std::map<std::pair<const SCEV *, Instruction *>,
+ AssertingVH<Value> >::iterator I =
+ InsertedExpressions.find(std::make_pair(S, InsertPt));
if (I != InsertedExpressions.end())
return I->second;
-
+
+ BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
+ BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+ Builder.SetInsertPoint(InsertPt->getParent(), InsertPt);
+
+ // Expand the expression into instructions.
Value *V = visit(S);
- InsertedExpressions[S] = V;
+
+ // Remember the expanded value for this SCEV at this location.
+ if (!PostIncLoop)
+ InsertedExpressions[std::make_pair(S, InsertPt)] = V;
+
+ restoreInsertPoint(SaveInsertBB, SaveInsertPt);
return V;
}
+void SCEVExpander::rememberInstruction(Value *I) {
+ if (!PostIncLoop)
+ InsertedValues.insert(I);
+
+ // If we just claimed an existing instruction and that instruction had
+ // been the insert point, adjust the insert point forward so that
+ // subsequently inserted code will be dominated.
+ if (Builder.GetInsertPoint() == I) {
+ BasicBlock::iterator It = cast<Instruction>(I);
+ do { ++It; } while (isInsertedInstruction(It));
+ Builder.SetInsertPoint(Builder.GetInsertBlock(), It);
+ }
+}
+
+void SCEVExpander::restoreInsertPoint(BasicBlock *BB, BasicBlock::iterator I) {
+ // If we aquired more instructions since the old insert point was saved,
+ // advance past them.
+ while (isInsertedInstruction(I)) ++I;
+
+ Builder.SetInsertPoint(BB, I);
+}
+
+/// getOrInsertCanonicalInductionVariable - This method returns the
+/// canonical induction variable of the specified type for the specified
+/// loop (inserting one if there is none). A canonical induction variable
+/// starts at zero and steps by one on each iteration.
+Value *
+SCEVExpander::getOrInsertCanonicalInductionVariable(const Loop *L,
+ const Type *Ty) {
+ assert(Ty->isIntegerTy() && "Can only insert integer induction variables!");
+ const SCEV *H = SE.getAddRecExpr(SE.getIntegerSCEV(0, Ty),
+ SE.getIntegerSCEV(1, Ty), L);
+ BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
+ BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+ Value *V = expandCodeFor(H, 0, L->getHeader()->begin());
+ if (SaveInsertBB)
+ restoreInsertPoint(SaveInsertBB, SaveInsertPt);
+ return V;
+}
projects / oota-llvm.git / blobdiff