X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FScalarEvolutionExpander.cpp;h=478d04749e2ee34cb322fa232c9e37c4cf86dcfe;hb=9feae9f0de032c66d01d16399a4c5296e38870e3;hp=4cc5ebc29534696ce986fa2738120352e50cb06e;hpb=667d787c0a21cf3f5dfcde03ca471162ba35b614;p=oota-llvm.git diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp index 4cc5ebc2953..478d04749e2 100644 --- a/lib/Analysis/ScalarEvolutionExpander.cpp +++ b/lib/Analysis/ScalarEvolutionExpander.cpp @@ -15,20 +15,29 @@ #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) { +/// 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 (opcode == Instruction::BitCast && V->getType() == Ty) + if (Op == Instruction::BitCast && V->getType() == Ty) return V; // Short-circuit unnecessary inttoptr<->ptrtoint casts. - if ((opcode == Instruction::PtrToInt || opcode == Instruction::IntToPtr) && + if ((Op == Instruction::PtrToInt || Op == Instruction::IntToPtr) && SE.getTypeSizeInBits(Ty) == SE.getTypeSizeInBits(V->getType())) { if (CastInst *CI = dyn_cast(V)) if ((CI->getOpcode() == Instruction::PtrToInt || @@ -44,17 +53,16 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V, return CE->getOperand(0); } - // FIXME: keep track of the cast instruction. if (Constant *C = dyn_cast(V)) - return ConstantExpr::getCast(opcode, C, Ty); - + return ConstantExpr::getCast(Op, C, Ty); + if (Argument *A = dyn_cast(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) if ((*UI)->getType() == Ty) if (CastInst *CI = dyn_cast(cast(*UI))) - if (CI->getOpcode() == opcode) { + 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()) { @@ -62,7 +70,7 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V, // The old cast is left in place in case it is being used // as an insert point. Instruction *NewCI = - CastInst::Create(opcode, V, Ty, "", + CastInst::Create(Op, V, Ty, "", A->getParent()->getEntryBlock().begin()); NewCI->takeName(CI); CI->replaceAllUsesWith(NewCI); @@ -71,9 +79,9 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V, return CI; } - Instruction *I = CastInst::Create(opcode, V, Ty, V->getName(), + Instruction *I = CastInst::Create(Op, V, Ty, V->getName(), A->getParent()->getEntryBlock().begin()); - InsertedValues.insert(I); + rememberInstruction(I); return I; } @@ -84,20 +92,22 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V, UI != E; ++UI) { if ((*UI)->getType() == Ty) if (CastInst *CI = dyn_cast(cast(*UI))) - if (CI->getOpcode() == opcode) { + if (CI->getOpcode() == Op) { BasicBlock::iterator It = I; ++It; if (isa(I)) It = cast(I)->getNormalDest()->begin(); while (isa(It)) ++It; if (It != BasicBlock::iterator(CI)) { - // Recreate the cast at the beginning of the entry block. + // 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(opcode, V, Ty, "", It); + Instruction *NewCI = CastInst::Create(Op, V, Ty, "", It); NewCI->takeName(CI); CI->replaceAllUsesWith(NewCI); + rememberInstruction(NewCI); return NewCI; } + rememberInstruction(CI); return CI; } } @@ -105,28 +115,15 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V, if (InvokeInst *II = dyn_cast(I)) IP = II->getNormalDest()->begin(); while (isa(IP)) ++IP; - Instruction *CI = CastInst::Create(opcode, V, Ty, V->getName(), IP); - InsertedValues.insert(CI); + Instruction *CI = CastInst::Create(Op, V, Ty, V->getName(), IP); + rememberInstruction(CI); return CI; } -/// InsertNoopCastOfTo - Insert a cast of V to the specified type, -/// which must be possible with a noop cast. -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!"); - return InsertCastOfTo(Op, V, Ty); -} - /// 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, BasicBlock::iterator InsertPt) { +Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, + Value *LHS, Value *RHS) { // Fold a binop with constant operands. if (Constant *CLHS = dyn_cast(LHS)) if (Constant *CRHS = dyn_cast(RHS)) @@ -134,10 +131,10 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS, // Do a quick scan to see if we have this binop nearby. If so, reuse it. unsigned ScanLimit = 6; - BasicBlock::iterator BlockBegin = InsertPt->getParent()->begin(); - if (InsertPt != BlockBegin) { - // Scanning starts from the last instruction before InsertPt. - BasicBlock::iterator IP = InsertPt; + 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 && @@ -146,10 +143,10 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS, if (IP == BlockBegin) break; } } - + // If we haven't found this binop, insert it. - Instruction *BO = BinaryOperator::Create(Opcode, LHS, RHS, "tmp", InsertPt); - InsertedValues.insert(BO); + Value *BO = Builder.CreateBinOp(Opcode, LHS, RHS, "tmp"); + rememberInstruction(BO); return BO; } @@ -160,54 +157,95 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS, /// 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 APInt &Factor, - ScalarEvolution &SE) { +static bool FactorOutConstant(const SCEV *&S, + const SCEV *&Remainder, + const SCEV *Factor, + ScalarEvolution &SE, + const TargetData *TD) { // Everything is divisible by one. - if (Factor == 1) + 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(S)) { - ConstantInt *CI = - ConstantInt::get(C->getValue()->getValue().sdiv(Factor)); - // 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 (C->isZero() || !CI->isZero()) { - const SCEV* Div = SE.getConstant(CI); - S = Div; - Remainder = - SE.getAddExpr(Remainder, - SE.getConstant(C->getValue()->getValue().srem(Factor))); + // 0/x == 0. + if (C->isZero()) return true; + // Check for divisibility. + if (const SCEVConstant *FC = dyn_cast(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(S)) - if (const SCEVConstant *C = dyn_cast(M->getOperand(0))) - if (!C->getValue()->getValue().srem(Factor)) { - const SmallVectorImpl &MOperands = M->getOperands(); - SmallVector NewMulOps(MOperands.begin(), MOperands.end()); - NewMulOps[0] = - SE.getConstant(C->getValue()->getValue().sdiv(Factor)); - S = SE.getMulExpr(NewMulOps); - return true; + if (const SCEVMulExpr *M = dyn_cast(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(Factor); + if (const SCEVConstant *C = dyn_cast(M->getOperand(0))) + if (!C->getValue()->getValue().srem(FC->getValue()->getValue())) { + const SmallVectorImpl &MOperands = M->getOperands(); + SmallVector 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 &MOperands = M->getOperands(); + SmallVector 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(S)) { - const SCEV* Step = A->getStepRecurrence(SE); - const SCEV* StepRem = SE.getIntegerSCEV(0, Step->getType()); - if (!FactorOutConstant(Step, StepRem, Factor, SE)) + 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)) + const SCEV *Start = A->getStart(); + if (!FactorOutConstant(Start, Remainder, Factor, SE, TD)) return false; S = SE.getAddRecExpr(Start, Step, A->getLoop()); return true; @@ -216,15 +254,81 @@ static bool FactorOutConstant(const SCEV* &S, return false; } -/// expandAddToGEP - Expand a SCEVAddExpr with a pointer type into a GEP -/// instead of using ptrtoint+arithmetic+inttoptr. This helps -/// BasicAliasAnalysis analyze the result. However, it suffers from the -/// underlying bug described in PR2831. Addition in LLVM currently always -/// has two's complement wrapping guaranteed. However, the semantics for -/// getelementptr overflow are ambiguous. In the common case though, this -/// expansion gets used when a GEP in the original code has been converted -/// into integer arithmetic, in which case the resulting code will be no -/// more undefined than it was originally. +/// 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 &Ops, + const Type *Ty, + ScalarEvolution &SE) { + unsigned NumAddRecs = 0; + for (unsigned i = Ops.size(); i > 0 && isa(Ops[i-1]); --i) + ++NumAddRecs; + // Group Ops into non-addrecs and addrecs. + SmallVector NoAddRecs(Ops.begin(), Ops.end() - NumAddRecs); + SmallVector 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(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 &Ops, + const Type *Ty, + ScalarEvolution &SE) { + // Find the addrecs. + SmallVector AddRecs; + for (unsigned i = 0, e = Ops.size(); i != e; ++i) + while (const SCEVAddRecExpr *A = dyn_cast(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(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 @@ -241,92 +345,132 @@ static bool FactorOutConstant(const SCEV* &S, /// 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, +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 GepIndices; - SmallVector Ops(op_begin, op_end); + SmallVector Ops(op_begin, op_end); bool AnyNonZeroIndices = false; - // Decend down the pointer's type and attempt to convert the other + // 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 (;;) { - APInt ElSize = APInt(SE.getTypeSizeInBits(Ty), - ElTy->isSized() ? SE.TD->getTypeAllocSize(ElTy) : 0); - SmallVector NewOps; - SmallVector ScaledOps; - for (unsigned i = 0, e = Ops.size(); i != e; ++i) { - // Split AddRecs up into parts as either of the parts may be usable - // without the other. - if (const SCEVAddRecExpr *A = dyn_cast(Ops[i])) - if (!A->getStart()->isZero()) { - const SCEV* Start = A->getStart(); - Ops.push_back(SE.getAddRecExpr(SE.getIntegerSCEV(0, A->getType()), - A->getStepRecurrence(SE), - A->getLoop())); - Ops[i] = Start; - ++e; + // If the scale size is not 0, attempt to factor out a scale for + // array indexing. + SmallVector ScaledOps; + if (ElTy->isSized()) { + const SCEV *ElSize = SE.getSizeOfExpr(ElTy); + if (!ElSize->isZero()) { + SmallVector 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 the scale size is not 0, attempt to factor out a scale. - if (ElSize != 0) { - const SCEV* Op = Ops[i]; - const SCEV* Remainder = SE.getIntegerSCEV(0, Op->getType()); - if (FactorOutConstant(Op, Remainder, ElSize, SE)) { - ScaledOps.push_back(Op); // Op now has ElSize factored out. - NewOps.push_back(Remainder); - continue; + // If we made any changes, update Ops. + if (!ScaledOps.empty()) { + Ops = NewOps; + SimplifyAddOperands(Ops, Ty, SE); } } - // If the operand was not divisible, add it to the list of operands - // we'll scan next iteration. - NewOps.push_back(Ops[i]); } - Ops = NewOps; - AnyNonZeroIndices |= !ScaledOps.empty(); + + // 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. - if (!Ops.empty()) - while (const StructType *STy = dyn_cast(ElTy)) { + while (const StructType *STy = dyn_cast(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(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::Int32Ty, ElIdx)); + 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; - continue; + 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(Ops[i])) { + const Type *CTy; + Constant *FieldNo; + if (U->isOffsetOf(CTy, FieldNo) && CTy == STy) { + GepIndices.push_back(FieldNo); + ElTy = + STy->getTypeAtIndex(cast(FieldNo)->getZExtValue()); + Ops[i] = SE.getConstant(Ty, 0); + AnyNonZeroIndices = true; + FoundFieldNo = true; + break; } } - 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(ElTy)) { + if (const ArrayType *ATy = dyn_cast(ElTy)) ElTy = ATy->getElementType(); - continue; - } - break; + 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::Int8Ty->getPointerTo(PTy->getAddressSpace())); + 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. @@ -336,10 +480,10 @@ Value *SCEVExpander::expandAddToGEP(const SCEV* const *op_begin, // Do a quick scan to see if we have this GEP nearby. If so, reuse it. unsigned ScanLimit = 6; - BasicBlock::iterator BlockBegin = InsertPt->getParent()->begin(); - if (InsertPt != BlockBegin) { - // Scanning starts from the last instruction before InsertPt. - BasicBlock::iterator IP = InsertPt; + 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 && @@ -349,40 +493,81 @@ Value *SCEVExpander::expandAddToGEP(const SCEV* const *op_begin, } } - Value *GEP = GetElementPtrInst::Create(V, Idx, "scevgep", InsertPt); - InsertedValues.insert(GEP); + // Emit a GEP. + Value *GEP = Builder.CreateGEP(V, Idx, "uglygep"); + rememberInstruction(GEP); return GEP; } - // Insert a pretty getelementptr. - Value *GEP = GetElementPtrInst::Create(V, - GepIndices.begin(), - GepIndices.end(), - "scevgep", 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)); - InsertedValues.insert(GEP); + rememberInstruction(GEP); return expand(SE.getAddExpr(Ops)); } +/// isNonConstantNegative - Return true if the specified scev is negated, but +/// not a constant. +static bool isNonConstantNegative(const SCEV *F) { + const SCEVMulExpr *Mul = dyn_cast(F); + if (!Mul) return false; + + // If there is a constant factor, it will be first. + const SCEVConstant *SC = dyn_cast(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()); - Value *V = expand(S->getOperand(S->getNumOperands()-1)); + + // 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 (S->getOperand(PIdx)->getType()->isPointerTy()) 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 (SE.TD) - if (const PointerType *PTy = dyn_cast(V->getType())) { - const SmallVectorImpl &Ops = S->getOperands(); - return expandAddToGEP(&Ops[0], &Ops[Ops.size() - 1], - PTy, Ty, V); - } + if (const PointerType *PTy = dyn_cast(V->getType())) { + // Take the operand at PIdx out of the list. + const SmallVectorImpl &Ops = S->getOperands(); + SmallVector 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 = S->getNumOperands()-2; i >= 0; --i) { - Value *W = expandCodeFor(S->getOperand(i), Ty); - V = InsertBinop(Instruction::Add, V, W, InsertPt); + 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; } @@ -400,12 +585,12 @@ Value *SCEVExpander::visitMulExpr(const SCEVMulExpr *S) { // Emit a bunch of multiply instructions for (; i >= FirstOp; --i) { Value *W = expandCodeFor(S->getOperand(i), Ty); - V = InsertBinop(Instruction::Mul, V, W, InsertPt); + V = InsertBinop(Instruction::Mul, V, W); } // -1 * ... ---> 0 - ... if (FirstOp == 1) - V = InsertBinop(Instruction::Sub, Constant::getNullValue(Ty), V, InsertPt); + V = InsertBinop(Instruction::Sub, Constant::getNullValue(Ty), V); return V; } @@ -417,18 +602,17 @@ Value *SCEVExpander::visitUDivExpr(const SCEVUDivExpr *S) { const APInt &RHS = SC->getValue()->getValue(); if (RHS.isPowerOf2()) return InsertBinop(Instruction::LShr, LHS, - ConstantInt::get(Ty, RHS.logBase2()), - InsertPt); + ConstantInt::get(Ty, RHS.logBase2())); } Value *RHS = expandCodeFor(S->getRHS(), Ty); - return InsertBinop(Instruction::UDiv, LHS, RHS, InsertPt); + 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, +static void ExposePointerBase(const SCEV *&Base, const SCEV *&Rest, ScalarEvolution &SE) { while (const SCEVAddRecExpr *A = dyn_cast(Base)) { Base = A->getStart(); @@ -439,14 +623,241 @@ static void ExposePointerBase(const SCEV* &Base, const SCEV* &Rest, } if (const SCEVAddExpr *A = dyn_cast(Base)) { Base = A->getOperand(A->getNumOperands()-1); - SmallVector NewAddOps(A->op_begin(), A->op_end()); + SmallVector 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(I); ++I) + if (SE.isSCEVable(PN->getType()) && + (SE.getEffectiveSCEVType(PN->getType()) == + SE.getEffectiveSCEVType(Normalized->getType())) && + SE.getSCEV(PN) == Normalized) + if (BasicBlock *LatchBlock = L->getLoopLatch()) { + Instruction *IncV = + cast(PN->getIncomingValueForBlock(LatchBlock)); + + // Determine if this is a well-behaved chain of instructions leading + // back to the PHI. It probably will be, if we're scanning an inner + // loop already visited by LSR for example, but it wouldn't have + // to be. + do { + if (IncV->getNumOperands() == 0 || isa(IncV)) { + IncV = 0; + break; + } + // If any of the operands don't dominate the insert position, bail. + // Addrec operands are always loop-invariant, so this can only happen + // if there are instructions which haven't been hoisted. + for (User::op_iterator OI = IncV->op_begin()+1, + OE = IncV->op_end(); OI != OE; ++OI) + if (Instruction *OInst = dyn_cast(OI)) + if (!SE.DT->dominates(OInst, IVIncInsertPos)) { + IncV = 0; + break; + } + if (!IncV) + break; + // Advance to the next instruction. + IncV = dyn_cast(IncV->getOperand(0)); + if (!IncV) + break; + if (IncV->mayHaveSideEffects()) { + IncV = 0; + break; + } + } while (IncV != PN); + + if (IncV) { + // Ok, the add recurrence looks usable. + // Remember this PHI, even in post-inc mode. + InsertedValues.insert(PN); + // Remember the increment. + IncV = cast(PN->getIncomingValueForBlock(LatchBlock)); + rememberInstruction(IncV); + if (L == IVIncInsertLoop) + do { + if (SE.DT->dominates(IncV, IVIncInsertPos)) + break; + // Make sure the increment is where we want it. But don't move it + // down past a potential existing post-inc user. + IncV->moveBefore(IVIncInsertPos); + IVIncInsertPos = IncV; + IncV = cast(IncV->getOperand(0)); + } while (IncV != PN); + 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 = ExpandTy->isPointerTy(); + 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(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(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(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(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(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(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(); @@ -454,7 +865,7 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) { PHINode *CanonicalIV = 0; if (PHINode *PN = L->getCanonicalInductionVariable()) if (SE.isSCEVable(PN->getType()) && - isa(SE.getEffectiveSCEVType(PN->getType())) && + SE.getEffectiveSCEVType(PN->getType())->isIntegerTy() && SE.getTypeSizeInBits(PN->getType()) >= SE.getTypeSizeInBits(Ty)) CanonicalIV = PN; @@ -463,45 +874,44 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) { if (CanonicalIV && SE.getTypeSizeInBits(CanonicalIV->getType()) > SE.getTypeSizeInBits(Ty)) { - const SCEV* Start = SE.getAnyExtendExpr(S->getStart(), - CanonicalIV->getType()); - const SCEV* Step = SE.getAnyExtendExpr(S->getStepRecurrence(SE), - CanonicalIV->getType()); - Value *V = expand(SE.getAddRecExpr(Start, Step, S->getLoop())); - BasicBlock::iterator SaveInsertPt = InsertPt; + const SmallVectorImpl &Ops = S->getOperands(); + SmallVector 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 = - next(BasicBlock::iterator(cast(V))); + llvm::next(BasicBlock::iterator(cast(V))); while (isa(NewInsertPt)) ++NewInsertPt; V = expandCodeFor(SE.getTruncateExpr(SE.getUnknown(V), Ty), 0, NewInsertPt); - InsertPt = SaveInsertPt; + restoreInsertPoint(SaveInsertBB, SaveInsertPt); return V; } // {X,+,F} --> X + {0,+,F} if (!S->getStart()->isZero()) { - const SmallVectorImpl &SOperands = S->getOperands(); - SmallVector NewOps(SOperands.begin(), SOperands.end()); + const SmallVectorImpl &SOperands = S->getOperands(); + SmallVector NewOps(SOperands.begin(), SOperands.end()); NewOps[0] = SE.getIntegerSCEV(0, Ty); - const SCEV* Rest = SE.getAddRecExpr(NewOps, L); + const SCEV *Rest = SE.getAddRecExpr(NewOps, L); // Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the // comments on expandAddToGEP for details. - if (SE.TD) { - 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(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(Base) && !isa(Base)) { - Value *StartV = expand(Base); - assert(StartV->getType() == PTy && "Pointer type mismatch for GEP!"); - return expandAddToGEP(RestArray, RestArray+1, PTy, Ty, StartV); - } + 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(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(Base) && !isa(Base)) { + Value *StartV = expand(Base); + assert(StartV->getType() == PTy && "Pointer type mismatch for GEP!"); + return expandAddToGEP(RestArray, RestArray+1, PTy, Ty, StartV); } } @@ -525,27 +935,21 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) { // specified loop. BasicBlock *Header = L->getHeader(); PHINode *PN = PHINode::Create(Ty, "indvar", Header->begin()); - InsertedValues.insert(PN); - PN->addIncoming(Constant::getNullValue(Ty), L->getLoopPreheader()); + rememberInstruction(PN); - 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?"); - - // 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()); - InsertedValues.insert(Add); - - 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 @@ -567,19 +971,19 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) { // 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. - const SCEV* IH = SE.getUnknown(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()); + const SCEV *NewS = S; + const SCEV *Ext = SE.getNoopOrAnyExtend(S, I->getType()); if (isa(Ext)) NewS = Ext; - const SCEV* V = cast(NewS)->evaluateAtIteration(IH, SE); + const SCEV *V = cast(NewS)->evaluateAtIteration(IH, SE); //cerr << "Evaluated: " << *this << "\n to: " << *V << "\n"; // Truncate the result down to the original type, if needed. - const SCEV* T = SE.getTruncateOrNoop(V, Ty); + const SCEV *T = SE.getTruncateOrNoop(V, Ty); return expand(T); } @@ -587,8 +991,8 @@ Value *SCEVExpander::visitTruncateExpr(const SCEVTruncateExpr *S) { const Type *Ty = SE.getEffectiveSCEVType(S->getType()); Value *V = expandCodeFor(S->getOperand(), SE.getEffectiveSCEVType(S->getOperand()->getType())); - Instruction *I = new TruncInst(V, Ty, "tmp.", InsertPt); - InsertedValues.insert(I); + Value *I = Builder.CreateTrunc(V, Ty, "tmp"); + rememberInstruction(I); return I; } @@ -596,8 +1000,8 @@ Value *SCEVExpander::visitZeroExtendExpr(const SCEVZeroExtendExpr *S) { const Type *Ty = SE.getEffectiveSCEVType(S->getType()); Value *V = expandCodeFor(S->getOperand(), SE.getEffectiveSCEVType(S->getOperand()->getType())); - Instruction *I = new ZExtInst(V, Ty, "tmp.", InsertPt); - InsertedValues.insert(I); + Value *I = Builder.CreateZExt(V, Ty, "tmp"); + rememberInstruction(I); return I; } @@ -605,42 +1009,60 @@ Value *SCEVExpander::visitSignExtendExpr(const SCEVSignExtendExpr *S) { const Type *Ty = SE.getEffectiveSCEVType(S->getType()); Value *V = expandCodeFor(S->getOperand(), SE.getEffectiveSCEVType(S->getOperand()->getType())); - Instruction *I = new SExtInst(V, Ty, "tmp.", InsertPt); - InsertedValues.insert(I); + Value *I = Builder.CreateSExt(V, Ty, "tmp"); + rememberInstruction(I); return I; } Value *SCEVExpander::visitSMaxExpr(const SCEVSMaxExpr *S) { - const Type *Ty = SE.getEffectiveSCEVType(S->getType()); - Value *LHS = expandCodeFor(S->getOperand(0), Ty); - for (unsigned i = 1; i < S->getNumOperands(); ++i) { + 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); - Instruction *ICmp = - new ICmpInst(ICmpInst::ICMP_SGT, LHS, RHS, "tmp", InsertPt); - InsertedValues.insert(ICmp); - Instruction *Sel = SelectInst::Create(ICmp, LHS, RHS, "smax", InsertPt); - InsertedValues.insert(Sel); + 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) { - const Type *Ty = SE.getEffectiveSCEVType(S->getType()); - Value *LHS = expandCodeFor(S->getOperand(0), Ty); - for (unsigned i = 1; i < S->getNumOperands(); ++i) { + 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); - Instruction *ICmp = - new ICmpInst(ICmpInst::ICMP_UGT, LHS, RHS, "tmp", InsertPt); - InsertedValues.insert(ICmp); - Instruction *Sel = SelectInst::Create(ICmp, LHS, RHS, "umax", InsertPt); - InsertedValues.insert(Sel); + 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::expandCodeFor(const SCEV* SH, const Type *Ty) { +Value *SCEVExpander::expandCodeFor(const SCEV *SH, const Type *Ty) { // Expand the code for this SCEV. Value *V = expand(SH); if (Ty) { @@ -652,11 +1074,10 @@ Value *SCEVExpander::expandCodeFor(const SCEV* SH, const Type *Ty) { } Value *SCEVExpander::expand(const SCEV *S) { - BasicBlock::iterator SaveInsertPt = InsertPt; - // Compute an insertion point for this SCEV object. Hoist the instructions // as far out in the loop nest as possible. - for (Loop *L = SE.LI->getLoopFor(InsertPt->getParent()); ; + Instruction *InsertPt = Builder.GetInsertPoint(); + for (Loop *L = SE.LI->getLoopFor(Builder.GetInsertBlock()); ; L = L->getParentLoop()) if (S->isLoopInvariant(L)) { if (!L) break; @@ -668,7 +1089,8 @@ Value *SCEVExpander::expand(const SCEV *S) { // 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; + while (isInsertedInstruction(InsertPt)) + InsertPt = llvm::next(BasicBlock::iterator(InsertPt)); break; } @@ -676,21 +1098,46 @@ Value *SCEVExpander::expand(const SCEV *S) { std::map, AssertingVH >::iterator I = InsertedExpressions.find(std::make_pair(S, InsertPt)); - if (I != InsertedExpressions.end()) { - InsertPt = SaveInsertPt; + 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); // Remember the expanded value for this SCEV at this location. - InsertedExpressions[std::make_pair(S, InsertPt)] = V; + if (!PostIncLoop) + InsertedExpressions[std::make_pair(S, InsertPt)] = V; - InsertPt = SaveInsertPt; + 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(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 @@ -698,11 +1145,13 @@ Value *SCEVExpander::expand(const SCEV *S) { Value * SCEVExpander::getOrInsertCanonicalInductionVariable(const Loop *L, const Type *Ty) { - assert(Ty->isInteger() && "Can only insert integer induction variables!"); - const SCEV* H = SE.getAddRecExpr(SE.getIntegerSCEV(0, 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::iterator SaveInsertPt = InsertPt; + BasicBlock *SaveInsertBB = Builder.GetInsertBlock(); + BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint(); Value *V = expandCodeFor(H, 0, L->getHeader()->begin()); - InsertPt = SaveInsertPt; + if (SaveInsertBB) + restoreInsertPoint(SaveInsertBB, SaveInsertPt); return V; }