// "Loop-Aware SLP in GCC" by Ira Rosen, Dorit Nuzman, Ayal Zaks.
//
//===----------------------------------------------------------------------===//
-#define SV_NAME "slp-vectorizer"
-#define DEBUG_TYPE "SLP"
-
#include "llvm/Transforms/Vectorize.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
-#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/TargetTransformInfo.h"
-#include "llvm/Analysis/Verifier.h"
-#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Value.h"
+#include "llvm/IR/Verifier.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Utils/VectorUtils.h"
#include <algorithm>
#include <map>
using namespace llvm;
+#define SV_NAME "slp-vectorizer"
+#define DEBUG_TYPE "SLP"
+
static cl::opt<int>
SLPCostThreshold("slp-threshold", cl::init(0), cl::Hidden,
cl::desc("Only vectorize if you gain more than this "
"number "));
+
+static cl::opt<bool>
+ShouldVectorizeHor("slp-vectorize-hor", cl::init(false), cl::Hidden,
+ cl::desc("Attempt to vectorize horizontal reductions"));
+
+static cl::opt<bool> ShouldStartVectorizeHorAtStore(
+ "slp-vectorize-hor-store", cl::init(false), cl::Hidden,
+ cl::desc(
+ "Attempt to vectorize horizontal reductions feeding into a store"));
+
namespace {
static const unsigned MinVecRegSize = 128;
static const unsigned RecursionMaxDepth = 12;
-/// RAII pattern to save the insertion point of the IR builder.
-class BuilderLocGuard {
-public:
- BuilderLocGuard(IRBuilder<> &B) : Builder(B), Loc(B.GetInsertPoint()),
- DbgLoc(B.getCurrentDebugLocation()) {}
- ~BuilderLocGuard() {
- Builder.SetCurrentDebugLocation(DbgLoc);
- if (Loc)
- Builder.SetInsertPoint(Loc);
- }
-
-private:
- // Prevent copying.
- BuilderLocGuard(const BuilderLocGuard &);
- BuilderLocGuard &operator=(const BuilderLocGuard &);
- IRBuilder<> &Builder;
- AssertingVH<Instruction> Loc;
- DebugLoc DbgLoc;
-};
-
/// A helper class for numbering instructions in multiple blocks.
/// Numbers start at zero for each basic block.
struct BlockNumbering {
return Opcode;
}
+/// \returns \p I after propagating metadata from \p VL.
+static Instruction *propagateMetadata(Instruction *I, ArrayRef<Value *> VL) {
+ Instruction *I0 = cast<Instruction>(VL[0]);
+ SmallVector<std::pair<unsigned, MDNode *>, 4> Metadata;
+ I0->getAllMetadataOtherThanDebugLoc(Metadata);
+
+ for (unsigned i = 0, n = Metadata.size(); i != n; ++i) {
+ unsigned Kind = Metadata[i].first;
+ MDNode *MD = Metadata[i].second;
+
+ for (int i = 1, e = VL.size(); MD && i != e; i++) {
+ Instruction *I = cast<Instruction>(VL[i]);
+ MDNode *IMD = I->getMetadata(Kind);
+
+ switch (Kind) {
+ default:
+ MD = 0; // Remove unknown metadata
+ break;
+ case LLVMContext::MD_tbaa:
+ MD = MDNode::getMostGenericTBAA(MD, IMD);
+ break;
+ case LLVMContext::MD_fpmath:
+ MD = MDNode::getMostGenericFPMath(MD, IMD);
+ break;
+ }
+ }
+ I->setMetadata(Kind, MD);
+ }
+ return I;
+}
+
/// \returns The type that all of the values in \p VL have or null if there
/// are different types.
static Type* getSameType(ArrayRef<Value *> VL) {
return true;
}
+static void reorderInputsAccordingToOpcode(ArrayRef<Value *> VL,
+ SmallVectorImpl<Value *> &Left,
+ SmallVectorImpl<Value *> &Right) {
+
+ SmallVector<Value *, 16> OrigLeft, OrigRight;
+
+ bool AllSameOpcodeLeft = true;
+ bool AllSameOpcodeRight = true;
+ for (unsigned i = 0, e = VL.size(); i != e; ++i) {
+ Instruction *I = cast<Instruction>(VL[i]);
+ Value *V0 = I->getOperand(0);
+ Value *V1 = I->getOperand(1);
+
+ OrigLeft.push_back(V0);
+ OrigRight.push_back(V1);
+
+ Instruction *I0 = dyn_cast<Instruction>(V0);
+ Instruction *I1 = dyn_cast<Instruction>(V1);
+
+ // Check whether all operands on one side have the same opcode. In this case
+ // we want to preserve the original order and not make things worse by
+ // reordering.
+ AllSameOpcodeLeft = I0;
+ AllSameOpcodeRight = I1;
+
+ if (i && AllSameOpcodeLeft) {
+ if(Instruction *P0 = dyn_cast<Instruction>(OrigLeft[i-1])) {
+ if(P0->getOpcode() != I0->getOpcode())
+ AllSameOpcodeLeft = false;
+ } else
+ AllSameOpcodeLeft = false;
+ }
+ if (i && AllSameOpcodeRight) {
+ if(Instruction *P1 = dyn_cast<Instruction>(OrigRight[i-1])) {
+ if(P1->getOpcode() != I1->getOpcode())
+ AllSameOpcodeRight = false;
+ } else
+ AllSameOpcodeRight = false;
+ }
+
+ // Sort two opcodes. In the code below we try to preserve the ability to use
+ // broadcast of values instead of individual inserts.
+ // vl1 = load
+ // vl2 = phi
+ // vr1 = load
+ // vr2 = vr2
+ // = vl1 x vr1
+ // = vl2 x vr2
+ // If we just sorted according to opcode we would leave the first line in
+ // tact but we would swap vl2 with vr2 because opcode(phi) > opcode(load).
+ // = vl1 x vr1
+ // = vr2 x vl2
+ // Because vr2 and vr1 are from the same load we loose the opportunity of a
+ // broadcast for the packed right side in the backend: we have [vr1, vl2]
+ // instead of [vr1, vr2=vr1].
+ if (I0 && I1) {
+ if(!i && I0->getOpcode() > I1->getOpcode()) {
+ Left.push_back(I1);
+ Right.push_back(I0);
+ } else if (i && I0->getOpcode() > I1->getOpcode() && Right[i-1] != I1) {
+ // Try not to destroy a broad cast for no apparent benefit.
+ Left.push_back(I1);
+ Right.push_back(I0);
+ } else if (i && I0->getOpcode() == I1->getOpcode() && Right[i-1] == I0) {
+ // Try preserve broadcasts.
+ Left.push_back(I1);
+ Right.push_back(I0);
+ } else if (i && I0->getOpcode() == I1->getOpcode() && Left[i-1] == I1) {
+ // Try preserve broadcasts.
+ Left.push_back(I1);
+ Right.push_back(I0);
+ } else {
+ Left.push_back(I0);
+ Right.push_back(I1);
+ }
+ continue;
+ }
+ // One opcode, put the instruction on the right.
+ if (I0) {
+ Left.push_back(V1);
+ Right.push_back(I0);
+ continue;
+ }
+ Left.push_back(V0);
+ Right.push_back(V1);
+ }
+
+ bool LeftBroadcast = isSplat(Left);
+ bool RightBroadcast = isSplat(Right);
+
+ // Don't reorder if the operands where good to begin with.
+ if (!(LeftBroadcast || RightBroadcast) &&
+ (AllSameOpcodeRight || AllSameOpcodeLeft)) {
+ Left = OrigLeft;
+ Right = OrigRight;
+ }
+}
+
/// Bottom Up SLP Vectorizer.
class BoUpSLP {
public:
typedef SmallPtrSet<Value *, 16> ValueSet;
typedef SmallVector<StoreInst *, 8> StoreList;
- BoUpSLP(Function *Func, ScalarEvolution *Se, DataLayout *Dl,
+ BoUpSLP(Function *Func, ScalarEvolution *Se, const DataLayout *Dl,
TargetTransformInfo *Tti, AliasAnalysis *Aa, LoopInfo *Li,
DominatorTree *Dt) :
F(Func), SE(Se), DL(Dl), TTI(Tti), AA(Aa), LI(Li), DT(Dt),
}
/// \brief Vectorize the tree that starts with the elements in \p VL.
- void vectorizeTree();
+ /// Returns the vectorized root.
+ Value *vectorizeTree();
/// \returns the vectorization cost of the subtree that starts at \p VL.
/// A negative number means that this is profitable.
int getTreeCost();
- /// Construct a vectorizable tree that starts at \p Roots.
- void buildTree(ArrayRef<Value *> Roots);
+ /// Construct a vectorizable tree that starts at \p Roots, ignoring users for
+ /// the purpose of scheduling and extraction in the \p UserIgnoreLst.
+ void buildTree(ArrayRef<Value *> Roots,
+ ArrayRef<Value *> UserIgnoreLst = None);
/// Clear the internal data structures that are created by 'buildTree'.
void deleteTree() {
/// \returns the pointer to the barrier instruction if we can't sink.
Value *getSinkBarrier(Instruction *Src, Instruction *Dst);
- /// \returns the index of the last instrucion in the BB from \p VL.
+ /// \returns the index of the last instruction in the BB from \p VL.
int getLastIndex(ArrayRef<Value *> VL);
/// \returns the Instruction in the bundle \p VL.
/// \returns a vector from a collection of scalars in \p VL.
Value *Gather(ArrayRef<Value *> VL, VectorType *Ty);
+ /// \returns whether the VectorizableTree is fully vectoriable and will
+ /// be beneficial even the tree height is tiny.
+ bool isFullyVectorizableTinyTree();
+
struct TreeEntry {
TreeEntry() : Scalars(), VectorizedValue(0), LastScalarIndex(0),
NeedToGather(0) {}
/// \returns true if the scalars in VL are equal to this entry.
bool isSame(ArrayRef<Value *> VL) const {
assert(VL.size() == Scalars.size() && "Invalid size");
- for (int i = 0, e = VL.size(); i != e; ++i)
- if (VL[i] != Scalars[i])
- return false;
- return true;
+ return std::equal(VL.begin(), VL.end(), Scalars.begin());
}
/// A vector of scalars.
/// Holds all of the instructions that we gathered.
SetVector<Instruction *> GatherSeq;
+ /// A list of blocks that we are going to CSE.
+ SetVector<BasicBlock *> CSEBlocks;
/// Numbers instructions in different blocks.
DenseMap<BasicBlock *, BlockNumbering> BlocksNumbers;
+ /// List of users to ignore during scheduling and that don't need extracting.
+ ArrayRef<Value *> UserIgnoreList;
+
// Analysis and block reference.
Function *F;
ScalarEvolution *SE;
- DataLayout *DL;
+ const DataLayout *DL;
TargetTransformInfo *TTI;
AliasAnalysis *AA;
LoopInfo *LI;
IRBuilder<> Builder;
};
-void BoUpSLP::buildTree(ArrayRef<Value *> Roots) {
+void BoUpSLP::buildTree(ArrayRef<Value *> Roots,
+ ArrayRef<Value *> UserIgnoreLst) {
deleteTree();
+ UserIgnoreList = UserIgnoreLst;
if (!getSameType(Roots))
return;
buildTree_rec(Roots, 0);
if (Entry->NeedToGather)
continue;
- for (Value::use_iterator User = Scalar->use_begin(),
- UE = Scalar->use_end(); User != UE; ++User) {
- DEBUG(dbgs() << "SLP: Checking user:" << **User << ".\n");
-
- bool Gathered = MustGather.count(*User);
+ for (User *U : Scalar->users()) {
+ DEBUG(dbgs() << "SLP: Checking user:" << *U << ".\n");
// Skip in-tree scalars that become vectors.
- if (ScalarToTreeEntry.count(*User) && !Gathered) {
+ if (ScalarToTreeEntry.count(U)) {
DEBUG(dbgs() << "SLP: \tInternal user will be removed:" <<
- **User << ".\n");
- int Idx = ScalarToTreeEntry[*User]; (void) Idx;
+ *U << ".\n");
+ int Idx = ScalarToTreeEntry[U]; (void) Idx;
assert(!VectorizableTree[Idx].NeedToGather && "Bad state");
continue;
}
+ Instruction *UserInst = dyn_cast<Instruction>(U);
+ if (!UserInst)
+ continue;
- if (!isa<Instruction>(*User))
+ // Ignore users in the user ignore list.
+ if (std::find(UserIgnoreList.begin(), UserIgnoreList.end(), UserInst) !=
+ UserIgnoreList.end())
continue;
- DEBUG(dbgs() << "SLP: Need to extract:" << **User << " from lane " <<
+ DEBUG(dbgs() << "SLP: Need to extract:" << *U << " from lane " <<
Lane << " from " << *Scalar << ".\n");
- ExternalUses.push_back(ExternalUser(Scalar, *User, Lane));
+ ExternalUses.push_back(ExternalUser(Scalar, U, Lane));
}
}
}
for (unsigned i = 0, e = VL.size(); i != e; ++i) {
Instruction *Scalar = cast<Instruction>(VL[i]);
DEBUG(dbgs() << "SLP: Checking users of " << *Scalar << ". \n");
- for (Value::use_iterator U = Scalar->use_begin(), UE = Scalar->use_end();
- U != UE; ++U) {
- DEBUG(dbgs() << "SLP: \tUser " << **U << ". \n");
- Instruction *User = dyn_cast<Instruction>(*U);
- if (!User) {
+ for (User *U : Scalar->users()) {
+ DEBUG(dbgs() << "SLP: \tUser " << *U << ". \n");
+ Instruction *UI = dyn_cast<Instruction>(U);
+ if (!UI) {
DEBUG(dbgs() << "SLP: Gathering due unknown user. \n");
newTreeEntry(VL, false);
return;
}
// We don't care if the user is in a different basic block.
- BasicBlock *UserBlock = User->getParent();
+ BasicBlock *UserBlock = UI->getParent();
if (UserBlock != BB) {
DEBUG(dbgs() << "SLP: User from a different basic block "
- << *User << ". \n");
+ << *UI << ". \n");
continue;
}
// If this is a PHINode within this basic block then we can place the
// extract wherever we want.
- if (isa<PHINode>(*User)) {
- DEBUG(dbgs() << "SLP: \tWe can schedule PHIs:" << *User << ". \n");
+ if (isa<PHINode>(*UI)) {
+ DEBUG(dbgs() << "SLP: \tWe can schedule PHIs:" << *UI << ". \n");
continue;
}
// Check if this is a safe in-tree user.
- if (ScalarToTreeEntry.count(User)) {
- int Idx = ScalarToTreeEntry[User];
+ if (ScalarToTreeEntry.count(UI)) {
+ int Idx = ScalarToTreeEntry[UI];
int VecLocation = VectorizableTree[Idx].LastScalarIndex;
if (VecLocation <= MyLastIndex) {
DEBUG(dbgs() << "SLP: Gathering due to unschedulable vector. \n");
newTreeEntry(VL, false);
return;
}
- DEBUG(dbgs() << "SLP: In-tree user (" << *User << ") at #" <<
+ DEBUG(dbgs() << "SLP: In-tree user (" << *UI << ") at #" <<
VecLocation << " vector value (" << *Scalar << ") at #"
<< MyLastIndex << ".\n");
continue;
}
+ // Ignore users in the user ignore list.
+ if (std::find(UserIgnoreList.begin(), UserIgnoreList.end(), UI) !=
+ UserIgnoreList.end())
+ continue;
+
// Make sure that we can schedule this unknown user.
BlockNumbering &BN = BlocksNumbers[BB];
- int UserIndex = BN.getIndex(User);
+ int UserIndex = BN.getIndex(UI);
if (UserIndex < MyLastIndex) {
DEBUG(dbgs() << "SLP: Can't schedule extractelement for "
- << *User << ". \n");
+ << *UI << ". \n");
newTreeEntry(VL, false);
return;
}
// Check that instructions in this bundle don't reference other instructions.
// The runtime of this check is O(N * N-1 * uses(N)) and a typical N is 4.
for (unsigned i = 0, e = VL.size(); i < e; ++i) {
- for (Value::use_iterator U = VL[i]->use_begin(), UE = VL[i]->use_end();
- U != UE; ++U) {
+ for (User *U : VL[i]->users()) {
for (unsigned j = 0; j < e; ++j) {
- if (i != j && *U == VL[j]) {
- DEBUG(dbgs() << "SLP: Intra-bundle dependencies!" << **U << ". \n");
+ if (i != j && U == VL[j]) {
+ DEBUG(dbgs() << "SLP: Intra-bundle dependencies!" << *U << ". \n");
newTreeEntry(VL, false);
return;
}
switch (Opcode) {
case Instruction::PHI: {
PHINode *PH = dyn_cast<PHINode>(VL0);
+
+ // Check for terminator values (e.g. invoke).
+ for (unsigned j = 0; j < VL.size(); ++j)
+ for (unsigned i = 0, e = PH->getNumIncomingValues(); i < e; ++i) {
+ TerminatorInst *Term = dyn_cast<TerminatorInst>(
+ cast<PHINode>(VL[j])->getIncomingValueForBlock(PH->getIncomingBlock(i)));
+ if (Term) {
+ DEBUG(dbgs() << "SLP: Need to swizzle PHINodes (TerminatorInst use).\n");
+ newTreeEntry(VL, false);
+ return;
+ }
+ }
+
newTreeEntry(VL, true);
DEBUG(dbgs() << "SLP: added a vector of PHINodes.\n");
ValueList Operands;
// Prepare the operand vector.
for (unsigned j = 0; j < VL.size(); ++j)
- Operands.push_back(cast<PHINode>(VL[j])->getIncomingValue(i));
+ Operands.push_back(cast<PHINode>(VL[j])->getIncomingValueForBlock(
+ PH->getIncomingBlock(i)));
buildTree_rec(Operands, Depth + 1);
}
}
case Instruction::Load: {
// Check if the loads are consecutive or of we need to swizzle them.
- for (unsigned i = 0, e = VL.size() - 1; i < e; ++i)
- if (!isConsecutiveAccess(VL[i], VL[i + 1])) {
+ for (unsigned i = 0, e = VL.size() - 1; i < e; ++i) {
+ LoadInst *L = cast<LoadInst>(VL[i]);
+ if (!L->isSimple() || !isConsecutiveAccess(VL[i], VL[i + 1])) {
newTreeEntry(VL, false);
DEBUG(dbgs() << "SLP: Need to swizzle loads.\n");
return;
}
-
+ }
newTreeEntry(VL, true);
DEBUG(dbgs() << "SLP: added a vector of loads.\n");
return;
newTreeEntry(VL, true);
DEBUG(dbgs() << "SLP: added a vector of bin op.\n");
+ // Sort operands of the instructions so that each side is more likely to
+ // have the same opcode.
+ if (isa<BinaryOperator>(VL0) && VL0->isCommutative()) {
+ ValueList Left, Right;
+ reorderInputsAccordingToOpcode(VL, Left, Right);
+ buildTree_rec(Left, Depth + 1);
+ buildTree_rec(Right, Depth + 1);
+ return;
+ }
+
for (unsigned i = 0, e = VL0->getNumOperands(); i < e; ++i) {
ValueList Operands;
// Prepare the operand vector.
for (unsigned i = 0, e = VL.size() - 1; i < e; ++i)
if (!isConsecutiveAccess(VL[i], VL[i + 1])) {
newTreeEntry(VL, false);
- DEBUG(dbgs() << "SLP: Non consecutive store.\n");
+ DEBUG(dbgs() << "SLP: Non-consecutive store.\n");
return;
}
buildTree_rec(Operands, Depth + 1);
return;
}
+ case Instruction::Call: {
+ // Check if the calls are all to the same vectorizable intrinsic.
+ IntrinsicInst *II = dyn_cast<IntrinsicInst>(VL[0]);
+ Intrinsic::ID ID = II ? II->getIntrinsicID() : Intrinsic::not_intrinsic;
+
+ if (!isTriviallyVectorizable(ID)) {
+ newTreeEntry(VL, false);
+ DEBUG(dbgs() << "SLP: Non-vectorizable call.\n");
+ return;
+ }
+
+ Function *Int = II->getCalledFunction();
+
+ for (unsigned i = 1, e = VL.size(); i != e; ++i) {
+ IntrinsicInst *II2 = dyn_cast<IntrinsicInst>(VL[i]);
+ if (!II2 || II2->getCalledFunction() != Int) {
+ newTreeEntry(VL, false);
+ DEBUG(dbgs() << "SLP: mismatched calls:" << *II << "!=" << *VL[i]
+ << "\n");
+ return;
+ }
+ }
+
+ newTreeEntry(VL, true);
+ for (unsigned i = 0, e = II->getNumArgOperands(); i != e; ++i) {
+ ValueList Operands;
+ // Prepare the operand vector.
+ for (unsigned j = 0; j < VL.size(); ++j) {
+ IntrinsicInst *II2 = dyn_cast<IntrinsicInst>(VL[j]);
+ Operands.push_back(II2->getArgOperand(i));
+ }
+ buildTree_rec(Operands, Depth + 1);
+ }
+ return;
+ }
default:
newTreeEntry(VL, false);
DEBUG(dbgs() << "SLP: Gathering unknown instruction.\n");
return 0;
}
case Instruction::ExtractElement: {
- if (CanReuseExtract(VL))
- return 0;
+ if (CanReuseExtract(VL)) {
+ int DeadCost = 0;
+ for (unsigned i = 0, e = VL.size(); i < e; ++i) {
+ ExtractElementInst *E = cast<ExtractElementInst>(VL[i]);
+ if (E->hasOneUse())
+ // Take credit for instruction that will become dead.
+ DeadCost +=
+ TTI->getVectorInstrCost(Instruction::ExtractElement, VecTy, i);
+ }
+ return -DeadCost;
+ }
return getGatherCost(VecTy);
}
case Instruction::ZExt:
TTI->getCmpSelInstrCost(Opcode, ScalarTy, Builder.getInt1Ty());
VecCost = TTI->getCmpSelInstrCost(Opcode, VecTy, MaskTy);
} else {
- ScalarCost = VecTy->getNumElements() *
- TTI->getArithmeticInstrCost(Opcode, ScalarTy);
- VecCost = TTI->getArithmeticInstrCost(Opcode, VecTy);
+ // Certain instructions can be cheaper to vectorize if they have a
+ // constant second vector operand.
+ TargetTransformInfo::OperandValueKind Op1VK =
+ TargetTransformInfo::OK_AnyValue;
+ TargetTransformInfo::OperandValueKind Op2VK =
+ TargetTransformInfo::OK_UniformConstantValue;
+
+ // If all operands are exactly the same ConstantInt then set the
+ // operand kind to OK_UniformConstantValue.
+ // If instead not all operands are constants, then set the operand kind
+ // to OK_AnyValue. If all operands are constants but not the same,
+ // then set the operand kind to OK_NonUniformConstantValue.
+ ConstantInt *CInt = NULL;
+ for (unsigned i = 0; i < VL.size(); ++i) {
+ const Instruction *I = cast<Instruction>(VL[i]);
+ if (!isa<ConstantInt>(I->getOperand(1))) {
+ Op2VK = TargetTransformInfo::OK_AnyValue;
+ break;
+ }
+ if (i == 0) {
+ CInt = cast<ConstantInt>(I->getOperand(1));
+ continue;
+ }
+ if (Op2VK == TargetTransformInfo::OK_UniformConstantValue &&
+ CInt != cast<ConstantInt>(I->getOperand(1)))
+ Op2VK = TargetTransformInfo::OK_NonUniformConstantValue;
+ }
+
+ ScalarCost =
+ VecTy->getNumElements() *
+ TTI->getArithmeticInstrCost(Opcode, ScalarTy, Op1VK, Op2VK);
+ VecCost = TTI->getArithmeticInstrCost(Opcode, VecTy, Op1VK, Op2VK);
}
return VecCost - ScalarCost;
}
// Cost of wide load - cost of scalar loads.
int ScalarLdCost = VecTy->getNumElements() *
TTI->getMemoryOpCost(Instruction::Load, ScalarTy, 1, 0);
- int VecLdCost = TTI->getMemoryOpCost(Instruction::Load, ScalarTy, 1, 0);
+ int VecLdCost = TTI->getMemoryOpCost(Instruction::Load, VecTy, 1, 0);
return VecLdCost - ScalarLdCost;
}
case Instruction::Store: {
// We know that we can merge the stores. Calculate the cost.
int ScalarStCost = VecTy->getNumElements() *
TTI->getMemoryOpCost(Instruction::Store, ScalarTy, 1, 0);
- int VecStCost = TTI->getMemoryOpCost(Instruction::Store, ScalarTy, 1, 0);
+ int VecStCost = TTI->getMemoryOpCost(Instruction::Store, VecTy, 1, 0);
return VecStCost - ScalarStCost;
}
+ case Instruction::Call: {
+ CallInst *CI = cast<CallInst>(VL0);
+ IntrinsicInst *II = cast<IntrinsicInst>(CI);
+ Intrinsic::ID ID = II->getIntrinsicID();
+
+ // Calculate the cost of the scalar and vector calls.
+ SmallVector<Type*, 4> ScalarTys, VecTys;
+ for (unsigned op = 0, opc = II->getNumArgOperands(); op!= opc; ++op) {
+ ScalarTys.push_back(CI->getArgOperand(op)->getType());
+ VecTys.push_back(VectorType::get(CI->getArgOperand(op)->getType(),
+ VecTy->getNumElements()));
+ }
+
+ int ScalarCallCost = VecTy->getNumElements() *
+ TTI->getIntrinsicInstrCost(ID, ScalarTy, ScalarTys);
+
+ int VecCallCost = TTI->getIntrinsicInstrCost(ID, VecTy, VecTys);
+
+ DEBUG(dbgs() << "SLP: Call cost "<< VecCallCost - ScalarCallCost
+ << " (" << VecCallCost << "-" << ScalarCallCost << ")"
+ << " for " << *II << "\n");
+
+ return VecCallCost - ScalarCallCost;
+ }
default:
llvm_unreachable("Unknown instruction");
}
}
+bool BoUpSLP::isFullyVectorizableTinyTree() {
+ DEBUG(dbgs() << "SLP: Check whether the tree with height " <<
+ VectorizableTree.size() << " is fully vectorizable .\n");
+
+ // We only handle trees of height 2.
+ if (VectorizableTree.size() != 2)
+ return false;
+
+ // Handle splat stores.
+ if (!VectorizableTree[0].NeedToGather && isSplat(VectorizableTree[1].Scalars))
+ return true;
+
+ // Gathering cost would be too much for tiny trees.
+ if (VectorizableTree[0].NeedToGather || VectorizableTree[1].NeedToGather)
+ return false;
+
+ return true;
+}
+
int BoUpSLP::getTreeCost() {
int Cost = 0;
DEBUG(dbgs() << "SLP: Calculating cost for tree of size " <<
VectorizableTree.size() << ".\n");
- // Don't vectorize tiny trees. Small load/store chains or consecutive stores
- // of constants will be vectoried in SelectionDAG in MergeConsecutiveStores.
- // The SelectionDAG vectorizer can only handle pairs (trees of height = 2).
- if (VectorizableTree.size() < 3) {
+ // We only vectorize tiny trees if it is fully vectorizable.
+ if (VectorizableTree.size() < 3 && !isFullyVectorizableTinyTree()) {
if (!VectorizableTree.size()) {
assert(!ExternalUses.size() && "We should not have any external users");
}
- return 0;
+ return INT_MAX;
}
unsigned BundleWidth = VectorizableTree[0].Scalars.size();
Cost += C;
}
+ SmallSet<Value *, 16> ExtractCostCalculated;
int ExtractCost = 0;
for (UserList::iterator I = ExternalUses.begin(), E = ExternalUses.end();
I != E; ++I) {
+ // We only add extract cost once for the same scalar.
+ if (!ExtractCostCalculated.insert(I->Scalar))
+ continue;
VectorType *VecTy = VectorType::get(I->Scalar->getType(), BundleWidth);
ExtractCost += TTI->getVectorInstrCost(Instruction::ExtractElement, VecTy,
I->Lane);
}
-
DEBUG(dbgs() << "SLP: Total Cost " << Cost + ExtractCost<< ".\n");
return Cost + ExtractCost;
}
Vec = Builder.CreateInsertElement(Vec, VL[i], Builder.getInt32(i));
if (Instruction *Insrt = dyn_cast<Instruction>(Vec)) {
GatherSeq.insert(Insrt);
+ CSEBlocks.insert(Insrt->getParent());
// Add to our 'need-to-extract' list.
if (ScalarToTreeEntry.count(VL[i])) {
}
Value *BoUpSLP::vectorizeTree(TreeEntry *E) {
- BuilderLocGuard Guard(Builder);
+ IRBuilder<>::InsertPointGuard Guard(Builder);
if (E->VectorizedValue) {
DEBUG(dbgs() << "SLP: Diamond merged for " << *E->Scalars[0] << ".\n");
switch (Opcode) {
case Instruction::PHI: {
PHINode *PH = dyn_cast<PHINode>(VL0);
- Builder.SetInsertPoint(PH->getParent()->getFirstInsertionPt());
+ Builder.SetInsertPoint(PH->getParent()->getFirstNonPHI());
Builder.SetCurrentDebugLocation(PH->getDebugLoc());
PHINode *NewPhi = Builder.CreatePHI(VecTy, PH->getNumIncomingValues());
E->VectorizedValue = NewPhi;
case Instruction::Or:
case Instruction::Xor: {
ValueList LHSVL, RHSVL;
- for (int i = 0, e = E->Scalars.size(); i < e; ++i) {
- LHSVL.push_back(cast<Instruction>(E->Scalars[i])->getOperand(0));
- RHSVL.push_back(cast<Instruction>(E->Scalars[i])->getOperand(1));
- }
+ if (isa<BinaryOperator>(VL0) && VL0->isCommutative())
+ reorderInputsAccordingToOpcode(E->Scalars, LHSVL, RHSVL);
+ else
+ for (int i = 0, e = E->Scalars.size(); i < e; ++i) {
+ LHSVL.push_back(cast<Instruction>(E->Scalars[i])->getOperand(0));
+ RHSVL.push_back(cast<Instruction>(E->Scalars[i])->getOperand(1));
+ }
setInsertPointAfterBundle(E->Scalars);
BinaryOperator *BinOp = cast<BinaryOperator>(VL0);
Value *V = Builder.CreateBinOp(BinOp->getOpcode(), LHS, RHS);
E->VectorizedValue = V;
+
+ if (Instruction *I = dyn_cast<Instruction>(V))
+ return propagateMetadata(I, E->Scalars);
+
return V;
}
case Instruction::Load: {
setInsertPointAfterBundle(E->Scalars);
LoadInst *LI = cast<LoadInst>(VL0);
- Value *VecPtr =
- Builder.CreateBitCast(LI->getPointerOperand(), VecTy->getPointerTo());
+ unsigned AS = LI->getPointerAddressSpace();
+
+ Value *VecPtr = Builder.CreateBitCast(LI->getPointerOperand(),
+ VecTy->getPointerTo(AS));
unsigned Alignment = LI->getAlignment();
LI = Builder.CreateLoad(VecPtr);
LI->setAlignment(Alignment);
E->VectorizedValue = LI;
- return LI;
+ return propagateMetadata(LI, E->Scalars);
}
case Instruction::Store: {
StoreInst *SI = cast<StoreInst>(VL0);
unsigned Alignment = SI->getAlignment();
+ unsigned AS = SI->getPointerAddressSpace();
ValueList ValueOp;
for (int i = 0, e = E->Scalars.size(); i < e; ++i)
setInsertPointAfterBundle(E->Scalars);
Value *VecValue = vectorizeTree(ValueOp);
- Value *VecPtr =
- Builder.CreateBitCast(SI->getPointerOperand(), VecTy->getPointerTo());
+ Value *VecPtr = Builder.CreateBitCast(SI->getPointerOperand(),
+ VecTy->getPointerTo(AS));
StoreInst *S = Builder.CreateStore(VecValue, VecPtr);
S->setAlignment(Alignment);
E->VectorizedValue = S;
- return S;
+ return propagateMetadata(S, E->Scalars);
+ }
+ case Instruction::Call: {
+ CallInst *CI = cast<CallInst>(VL0);
+
+ setInsertPointAfterBundle(E->Scalars);
+ std::vector<Value *> OpVecs;
+ for (int j = 0, e = CI->getNumArgOperands(); j < e; ++j) {
+ ValueList OpVL;
+ for (int i = 0, e = E->Scalars.size(); i < e; ++i) {
+ CallInst *CEI = cast<CallInst>(E->Scalars[i]);
+ OpVL.push_back(CEI->getArgOperand(j));
+ }
+
+ Value *OpVec = vectorizeTree(OpVL);
+ DEBUG(dbgs() << "SLP: OpVec[" << j << "]: " << *OpVec << "\n");
+ OpVecs.push_back(OpVec);
+ }
+
+ Module *M = F->getParent();
+ IntrinsicInst *II = cast<IntrinsicInst>(CI);
+ Intrinsic::ID ID = II->getIntrinsicID();
+ Type *Tys[] = { VectorType::get(CI->getType(), E->Scalars.size()) };
+ Function *CF = Intrinsic::getDeclaration(M, ID, Tys);
+ Value *V = Builder.CreateCall(CF, OpVecs);
+ E->VectorizedValue = V;
+ return V;
}
default:
llvm_unreachable("unknown inst");
return 0;
}
-void BoUpSLP::vectorizeTree() {
+Value *BoUpSLP::vectorizeTree() {
Builder.SetInsertPoint(F->getEntryBlock().begin());
vectorizeTree(&VectorizableTree[0]);
// Skip users that we already RAUW. This happens when one instruction
// has multiple uses of the same value.
- if (std::find(Scalar->use_begin(), Scalar->use_end(), User) ==
- Scalar->use_end())
+ if (std::find(Scalar->user_begin(), Scalar->user_end(), User) ==
+ Scalar->user_end())
continue;
assert(ScalarToTreeEntry.count(Scalar) && "Invalid scalar");
Value *Lane = Builder.getInt32(it->Lane);
// Generate extracts for out-of-tree users.
// Find the insertion point for the extractelement lane.
- if (PHINode *PN = dyn_cast<PHINode>(Vec)) {
- Builder.SetInsertPoint(PN->getParent()->getFirstInsertionPt());
- Value *Ex = Builder.CreateExtractElement(Vec, Lane);
- User->replaceUsesOfWith(Scalar, Ex);
- } else if (isa<Instruction>(Vec)){
+ if (isa<Instruction>(Vec)){
if (PHINode *PH = dyn_cast<PHINode>(User)) {
for (int i = 0, e = PH->getNumIncomingValues(); i != e; ++i) {
if (PH->getIncomingValue(i) == Scalar) {
Builder.SetInsertPoint(PH->getIncomingBlock(i)->getTerminator());
Value *Ex = Builder.CreateExtractElement(Vec, Lane);
+ CSEBlocks.insert(PH->getIncomingBlock(i));
PH->setOperand(i, Ex);
}
}
} else {
Builder.SetInsertPoint(cast<Instruction>(User));
Value *Ex = Builder.CreateExtractElement(Vec, Lane);
+ CSEBlocks.insert(cast<Instruction>(User)->getParent());
User->replaceUsesOfWith(Scalar, Ex);
}
} else {
Builder.SetInsertPoint(F->getEntryBlock().begin());
Value *Ex = Builder.CreateExtractElement(Vec, Lane);
+ CSEBlocks.insert(&F->getEntryBlock());
User->replaceUsesOfWith(Scalar, Ex);
}
Type *Ty = Scalar->getType();
if (!Ty->isVoidTy()) {
- for (Value::use_iterator User = Scalar->use_begin(),
- UE = Scalar->use_end(); User != UE; ++User) {
- DEBUG(dbgs() << "SLP: \tvalidating user:" << **User << ".\n");
- assert(!MustGather.count(*User) &&
- "Replacing gathered value with undef");
- assert(ScalarToTreeEntry.count(*User) &&
+#ifndef NDEBUG
+ for (User *U : Scalar->users()) {
+ DEBUG(dbgs() << "SLP: \tvalidating user:" << *U << ".\n");
+
+ assert((ScalarToTreeEntry.count(U) ||
+ // It is legal to replace users in the ignorelist by undef.
+ (std::find(UserIgnoreList.begin(), UserIgnoreList.end(), U) !=
+ UserIgnoreList.end())) &&
"Replacing out-of-tree value with undef");
}
+#endif
Value *Undef = UndefValue::get(Ty);
Scalar->replaceAllUsesWith(Undef);
}
BlocksNumbers[it].forget();
}
Builder.ClearInsertionPoint();
+
+ return VectorizableTree[0].VectorizedValue;
}
void BoUpSLP::optimizeGatherSequence() {
Insert->moveBefore(PreHeader->getTerminator());
}
+ // Sort blocks by domination. This ensures we visit a block after all blocks
+ // dominating it are visited.
+ SmallVector<BasicBlock *, 8> CSEWorkList(CSEBlocks.begin(), CSEBlocks.end());
+ std::stable_sort(CSEWorkList.begin(), CSEWorkList.end(),
+ [this](const BasicBlock *A, const BasicBlock *B) {
+ return DT->properlyDominates(A, B);
+ });
+
// Perform O(N^2) search over the gather sequences and merge identical
// instructions. TODO: We can further optimize this scan if we split the
// instructions into different buckets based on the insert lane.
- SmallPtrSet<Instruction*, 16> Visited;
- SmallVector<Instruction*, 16> ToRemove;
- ReversePostOrderTraversal<Function*> RPOT(F);
- for (ReversePostOrderTraversal<Function*>::rpo_iterator I = RPOT.begin(),
- E = RPOT.end(); I != E; ++I) {
+ SmallVector<Instruction *, 16> Visited;
+ for (SmallVectorImpl<BasicBlock *>::iterator I = CSEWorkList.begin(),
+ E = CSEWorkList.end();
+ I != E; ++I) {
+ assert((I == CSEWorkList.begin() || !DT->dominates(*I, *std::prev(I))) &&
+ "Worklist not sorted properly!");
BasicBlock *BB = *I;
- // For all instructions in the function:
- for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; ++it) {
- Instruction *In = it;
- if ((!isa<InsertElementInst>(In) && !isa<ExtractElementInst>(In)) ||
- !GatherSeq.count(In))
+ // For all instructions in blocks containing gather sequences:
+ for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e;) {
+ Instruction *In = it++;
+ if (!isa<InsertElementInst>(In) && !isa<ExtractElementInst>(In))
continue;
// Check if we can replace this instruction with any of the
// visited instructions.
- for (SmallPtrSet<Instruction*, 16>::iterator v = Visited.begin(),
- ve = Visited.end(); v != ve; ++v) {
+ for (SmallVectorImpl<Instruction *>::iterator v = Visited.begin(),
+ ve = Visited.end();
+ v != ve; ++v) {
if (In->isIdenticalTo(*v) &&
DT->dominates((*v)->getParent(), In->getParent())) {
In->replaceAllUsesWith(*v);
- ToRemove.push_back(In);
+ In->eraseFromParent();
In = 0;
break;
}
}
- if (In)
- Visited.insert(In);
+ if (In) {
+ assert(std::find(Visited.begin(), Visited.end(), In) == Visited.end());
+ Visited.push_back(In);
+ }
}
}
-
- // Erase all of the instructions that we RAUWed.
- for (SmallVectorImpl<Instruction *>::iterator v = ToRemove.begin(),
- ve = ToRemove.end(); v != ve; ++v) {
- assert((*v)->getNumUses() == 0 && "Can't remove instructions with uses");
- (*v)->eraseFromParent();
- }
+ CSEBlocks.clear();
+ GatherSeq.clear();
}
/// The SLPVectorizer Pass.
}
ScalarEvolution *SE;
- DataLayout *DL;
+ const DataLayout *DL;
TargetTransformInfo *TTI;
AliasAnalysis *AA;
LoopInfo *LI;
DominatorTree *DT;
- virtual bool runOnFunction(Function &F) {
+ bool runOnFunction(Function &F) override {
+ if (skipOptnoneFunction(F))
+ return false;
+
SE = &getAnalysis<ScalarEvolution>();
- DL = getAnalysisIfAvailable<DataLayout>();
+ DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
+ DL = DLP ? &DLP->getDataLayout() : 0;
TTI = &getAnalysis<TargetTransformInfo>();
AA = &getAnalysis<AliasAnalysis>();
LI = &getAnalysis<LoopInfo>();
- DT = &getAnalysis<DominatorTree>();
+ DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
StoreRefs.clear();
bool Changed = false;
+ // If the target claims to have no vector registers don't attempt
+ // vectorization.
+ if (!TTI->getNumberOfRegisters(true))
+ return false;
+
// Must have DataLayout. We can't require it because some tests run w/o
// triple.
if (!DL)
DEBUG(dbgs() << "SLP: Analyzing blocks in " << F.getName() << ".\n");
- // Use the bollom up slp vectorizer to construct chains that start with
+ // Use the bottom up slp vectorizer to construct chains that start with
// he store instructions.
BoUpSLP R(&F, SE, DL, TTI, AA, LI, DT);
return Changed;
}
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
FunctionPass::getAnalysisUsage(AU);
AU.addRequired<ScalarEvolution>();
AU.addRequired<AliasAnalysis>();
AU.addRequired<TargetTransformInfo>();
AU.addRequired<LoopInfo>();
- AU.addRequired<DominatorTree>();
+ AU.addRequired<DominatorTreeWrapperPass>();
AU.addPreserved<LoopInfo>();
- AU.addPreserved<DominatorTree>();
+ AU.addPreserved<DominatorTreeWrapperPass>();
AU.setPreservesCFG();
}
bool tryToVectorizePair(Value *A, Value *B, BoUpSLP &R);
/// \brief Try to vectorize a list of operands.
+ /// \@param BuildVector A list of users to ignore for the purpose of
+ /// scheduling and that don't need extracting.
/// \returns true if a value was vectorized.
- bool tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R);
+ bool tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R,
+ ArrayRef<Value *> BuildVector = None);
/// \brief Try to vectorize a chain that may start at the operands of \V;
bool tryToVectorize(BinaryOperator *V, BoUpSLP &R);
StoreListMap StoreRefs;
};
+/// \brief Check that the Values in the slice in VL array are still existent in
+/// the WeakVH array.
+/// Vectorization of part of the VL array may cause later values in the VL array
+/// to become invalid. We track when this has happened in the WeakVH array.
+static bool hasValueBeenRAUWed(ArrayRef<Value *> &VL,
+ SmallVectorImpl<WeakVH> &VH,
+ unsigned SliceBegin,
+ unsigned SliceSize) {
+ for (unsigned i = SliceBegin; i < SliceBegin + SliceSize; ++i)
+ if (VH[i] != VL[i])
+ return true;
+
+ return false;
+}
+
bool SLPVectorizer::vectorizeStoreChain(ArrayRef<Value *> Chain,
int CostThreshold, BoUpSLP &R) {
unsigned ChainLen = Chain.size();
if (!isPowerOf2_32(Sz) || VF < 2)
return false;
+ // Keep track of values that were deleted by vectorizing in the loop below.
+ SmallVector<WeakVH, 8> TrackValues(Chain.begin(), Chain.end());
+
bool Changed = false;
// Look for profitable vectorizable trees at all offsets, starting at zero.
for (unsigned i = 0, e = ChainLen; i < e; ++i) {
if (i + VF > e)
break;
+
+ // Check that a previous iteration of this loop did not delete the Value.
+ if (hasValueBeenRAUWed(Chain, TrackValues, i, VF))
+ continue;
+
DEBUG(dbgs() << "SLP: Analyzing " << VF << " stores at offset " << i
<< "\n");
ArrayRef<Value *> Operands = Chain.slice(i, VF);
}
}
- return Changed;
+ return Changed;
}
bool SLPVectorizer::vectorizeStores(ArrayRef<StoreInst *> Stores,
if (!SI)
continue;
+ // Don't touch volatile stores.
+ if (!SI->isSimple())
+ continue;
+
// Check that the pointer points to scalars.
Type *Ty = SI->getValueOperand()->getType();
if (Ty->isAggregateType() || Ty->isVectorTy())
return 0;
- // Find the base of the GEP.
- Value *Ptr = SI->getPointerOperand();
- if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Ptr))
- Ptr = GEP->getPointerOperand();
+ // Find the base pointer.
+ Value *Ptr = GetUnderlyingObject(SI->getPointerOperand(), DL);
// Save the store locations.
StoreRefs[Ptr].push_back(SI);
return tryToVectorizeList(VL, R);
}
-bool SLPVectorizer::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R) {
+bool SLPVectorizer::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R,
+ ArrayRef<Value *> BuildVector) {
if (VL.size() < 2)
return false;
// Check that all of the parts are scalar instructions of the same type.
Instruction *I0 = dyn_cast<Instruction>(VL[0]);
if (!I0)
- return 0;
+ return false;
unsigned Opcode0 = I0->getOpcode();
+ Type *Ty0 = I0->getType();
+ unsigned Sz = DL->getTypeSizeInBits(Ty0);
+ unsigned VF = MinVecRegSize / Sz;
+
for (int i = 0, e = VL.size(); i < e; ++i) {
Type *Ty = VL[i]->getType();
if (Ty->isAggregateType() || Ty->isVectorTy())
- return 0;
+ return false;
Instruction *Inst = dyn_cast<Instruction>(VL[i]);
if (!Inst || Inst->getOpcode() != Opcode0)
- return 0;
+ return false;
}
- R.buildTree(VL);
- int Cost = R.getTreeCost();
+ bool Changed = false;
- if (Cost >= -SLPCostThreshold)
- return false;
+ // Keep track of values that were deleted by vectorizing in the loop below.
+ SmallVector<WeakVH, 8> TrackValues(VL.begin(), VL.end());
- DEBUG(dbgs() << "SLP: Vectorizing pair at cost:" << Cost << ".\n");
- R.vectorizeTree();
- return true;
+ for (unsigned i = 0, e = VL.size(); i < e; ++i) {
+ unsigned OpsWidth = 0;
+
+ if (i + VF > e)
+ OpsWidth = e - i;
+ else
+ OpsWidth = VF;
+
+ if (!isPowerOf2_32(OpsWidth) || OpsWidth < 2)
+ break;
+
+ // Check that a previous iteration of this loop did not delete the Value.
+ if (hasValueBeenRAUWed(VL, TrackValues, i, OpsWidth))
+ continue;
+
+ DEBUG(dbgs() << "SLP: Analyzing " << OpsWidth << " operations "
+ << "\n");
+ ArrayRef<Value *> Ops = VL.slice(i, OpsWidth);
+
+ ArrayRef<Value *> BuildVectorSlice;
+ if (!BuildVector.empty())
+ BuildVectorSlice = BuildVector.slice(i, OpsWidth);
+
+ R.buildTree(Ops, BuildVectorSlice);
+ int Cost = R.getTreeCost();
+
+ if (Cost < -SLPCostThreshold) {
+ DEBUG(dbgs() << "SLP: Vectorizing list at cost:" << Cost << ".\n");
+ Value *VectorizedRoot = R.vectorizeTree();
+
+ // Reconstruct the build vector by extracting the vectorized root. This
+ // way we handle the case where some elements of the vector are undefined.
+ // (return (inserelt <4 xi32> (insertelt undef (opd0) 0) (opd1) 2))
+ if (!BuildVectorSlice.empty()) {
+ Instruction *InsertAfter = cast<Instruction>(VectorizedRoot);
+ for (auto &V : BuildVectorSlice) {
+ InsertElementInst *IE = cast<InsertElementInst>(V);
+ IRBuilder<> Builder(++BasicBlock::iterator(InsertAfter));
+ Instruction *Extract = cast<Instruction>(
+ Builder.CreateExtractElement(VectorizedRoot, IE->getOperand(2)));
+ IE->setOperand(1, Extract);
+ IE->removeFromParent();
+ IE->insertAfter(Extract);
+ InsertAfter = IE;
+ }
+ }
+ // Move to the next bundle.
+ i += VF - 1;
+ Changed = true;
+ }
+ }
+
+ return Changed;
}
bool SLPVectorizer::tryToVectorize(BinaryOperator *V, BoUpSLP &R) {
return 0;
}
+/// \brief Generate a shuffle mask to be used in a reduction tree.
+///
+/// \param VecLen The length of the vector to be reduced.
+/// \param NumEltsToRdx The number of elements that should be reduced in the
+/// vector.
+/// \param IsPairwise Whether the reduction is a pairwise or splitting
+/// reduction. A pairwise reduction will generate a mask of
+/// <0,2,...> or <1,3,..> while a splitting reduction will generate
+/// <2,3, undef,undef> for a vector of 4 and NumElts = 2.
+/// \param IsLeft True will generate a mask of even elements, odd otherwise.
+static Value *createRdxShuffleMask(unsigned VecLen, unsigned NumEltsToRdx,
+ bool IsPairwise, bool IsLeft,
+ IRBuilder<> &Builder) {
+ assert((IsPairwise || !IsLeft) && "Don't support a <0,1,undef,...> mask");
+
+ SmallVector<Constant *, 32> ShuffleMask(
+ VecLen, UndefValue::get(Builder.getInt32Ty()));
+
+ if (IsPairwise)
+ // Build a mask of 0, 2, ... (left) or 1, 3, ... (right).
+ for (unsigned i = 0; i != NumEltsToRdx; ++i)
+ ShuffleMask[i] = Builder.getInt32(2 * i + !IsLeft);
+ else
+ // Move the upper half of the vector to the lower half.
+ for (unsigned i = 0; i != NumEltsToRdx; ++i)
+ ShuffleMask[i] = Builder.getInt32(NumEltsToRdx + i);
+
+ return ConstantVector::get(ShuffleMask);
+}
+
+
+/// Model horizontal reductions.
+///
+/// A horizontal reduction is a tree of reduction operations (currently add and
+/// fadd) that has operations that can be put into a vector as its leaf.
+/// For example, this tree:
+///
+/// mul mul mul mul
+/// \ / \ /
+/// + +
+/// \ /
+/// +
+/// This tree has "mul" as its reduced values and "+" as its reduction
+/// operations. A reduction might be feeding into a store or a binary operation
+/// feeding a phi.
+/// ...
+/// \ /
+/// +
+/// |
+/// phi +=
+///
+/// Or:
+/// ...
+/// \ /
+/// +
+/// |
+/// *p =
+///
+class HorizontalReduction {
+ SmallVector<Value *, 16> ReductionOps;
+ SmallVector<Value *, 32> ReducedVals;
+
+ BinaryOperator *ReductionRoot;
+ PHINode *ReductionPHI;
+
+ /// The opcode of the reduction.
+ unsigned ReductionOpcode;
+ /// The opcode of the values we perform a reduction on.
+ unsigned ReducedValueOpcode;
+ /// The width of one full horizontal reduction operation.
+ unsigned ReduxWidth;
+ /// Should we model this reduction as a pairwise reduction tree or a tree that
+ /// splits the vector in halves and adds those halves.
+ bool IsPairwiseReduction;
+
+public:
+ HorizontalReduction()
+ : ReductionRoot(0), ReductionPHI(0), ReductionOpcode(0),
+ ReducedValueOpcode(0), ReduxWidth(0), IsPairwiseReduction(false) {}
+
+ /// \brief Try to find a reduction tree.
+ bool matchAssociativeReduction(PHINode *Phi, BinaryOperator *B,
+ const DataLayout *DL) {
+ assert((!Phi ||
+ std::find(Phi->op_begin(), Phi->op_end(), B) != Phi->op_end()) &&
+ "Thi phi needs to use the binary operator");
+
+ // We could have a initial reductions that is not an add.
+ // r *= v1 + v2 + v3 + v4
+ // In such a case start looking for a tree rooted in the first '+'.
+ if (Phi) {
+ if (B->getOperand(0) == Phi) {
+ Phi = 0;
+ B = dyn_cast<BinaryOperator>(B->getOperand(1));
+ } else if (B->getOperand(1) == Phi) {
+ Phi = 0;
+ B = dyn_cast<BinaryOperator>(B->getOperand(0));
+ }
+ }
+
+ if (!B)
+ return false;
+
+ Type *Ty = B->getType();
+ if (Ty->isVectorTy())
+ return false;
+
+ ReductionOpcode = B->getOpcode();
+ ReducedValueOpcode = 0;
+ ReduxWidth = MinVecRegSize / DL->getTypeSizeInBits(Ty);
+ ReductionRoot = B;
+ ReductionPHI = Phi;
+
+ if (ReduxWidth < 4)
+ return false;
+
+ // We currently only support adds.
+ if (ReductionOpcode != Instruction::Add &&
+ ReductionOpcode != Instruction::FAdd)
+ return false;
+
+ // Post order traverse the reduction tree starting at B. We only handle true
+ // trees containing only binary operators.
+ SmallVector<std::pair<BinaryOperator *, unsigned>, 32> Stack;
+ Stack.push_back(std::make_pair(B, 0));
+ while (!Stack.empty()) {
+ BinaryOperator *TreeN = Stack.back().first;
+ unsigned EdgeToVist = Stack.back().second++;
+ bool IsReducedValue = TreeN->getOpcode() != ReductionOpcode;
+
+ // Only handle trees in the current basic block.
+ if (TreeN->getParent() != B->getParent())
+ return false;
+
+ // Each tree node needs to have one user except for the ultimate
+ // reduction.
+ if (!TreeN->hasOneUse() && TreeN != B)
+ return false;
+
+ // Postorder vist.
+ if (EdgeToVist == 2 || IsReducedValue) {
+ if (IsReducedValue) {
+ // Make sure that the opcodes of the operations that we are going to
+ // reduce match.
+ if (!ReducedValueOpcode)
+ ReducedValueOpcode = TreeN->getOpcode();
+ else if (ReducedValueOpcode != TreeN->getOpcode())
+ return false;
+ ReducedVals.push_back(TreeN);
+ } else {
+ // We need to be able to reassociate the adds.
+ if (!TreeN->isAssociative())
+ return false;
+ ReductionOps.push_back(TreeN);
+ }
+ // Retract.
+ Stack.pop_back();
+ continue;
+ }
+
+ // Visit left or right.
+ Value *NextV = TreeN->getOperand(EdgeToVist);
+ BinaryOperator *Next = dyn_cast<BinaryOperator>(NextV);
+ if (Next)
+ Stack.push_back(std::make_pair(Next, 0));
+ else if (NextV != Phi)
+ return false;
+ }
+ return true;
+ }
+
+ /// \brief Attempt to vectorize the tree found by
+ /// matchAssociativeReduction.
+ bool tryToReduce(BoUpSLP &V, TargetTransformInfo *TTI) {
+ if (ReducedVals.empty())
+ return false;
+
+ unsigned NumReducedVals = ReducedVals.size();
+ if (NumReducedVals < ReduxWidth)
+ return false;
+
+ Value *VectorizedTree = 0;
+ IRBuilder<> Builder(ReductionRoot);
+ FastMathFlags Unsafe;
+ Unsafe.setUnsafeAlgebra();
+ Builder.SetFastMathFlags(Unsafe);
+ unsigned i = 0;
+
+ for (; i < NumReducedVals - ReduxWidth + 1; i += ReduxWidth) {
+ ArrayRef<Value *> ValsToReduce(&ReducedVals[i], ReduxWidth);
+ V.buildTree(ValsToReduce, ReductionOps);
+
+ // Estimate cost.
+ int Cost = V.getTreeCost() + getReductionCost(TTI, ReducedVals[i]);
+ if (Cost >= -SLPCostThreshold)
+ break;
+
+ DEBUG(dbgs() << "SLP: Vectorizing horizontal reduction at cost:" << Cost
+ << ". (HorRdx)\n");
+
+ // Vectorize a tree.
+ DebugLoc Loc = cast<Instruction>(ReducedVals[i])->getDebugLoc();
+ Value *VectorizedRoot = V.vectorizeTree();
+
+ // Emit a reduction.
+ Value *ReducedSubTree = emitReduction(VectorizedRoot, Builder);
+ if (VectorizedTree) {
+ Builder.SetCurrentDebugLocation(Loc);
+ VectorizedTree = createBinOp(Builder, ReductionOpcode, VectorizedTree,
+ ReducedSubTree, "bin.rdx");
+ } else
+ VectorizedTree = ReducedSubTree;
+ }
+
+ if (VectorizedTree) {
+ // Finish the reduction.
+ for (; i < NumReducedVals; ++i) {
+ Builder.SetCurrentDebugLocation(
+ cast<Instruction>(ReducedVals[i])->getDebugLoc());
+ VectorizedTree = createBinOp(Builder, ReductionOpcode, VectorizedTree,
+ ReducedVals[i]);
+ }
+ // Update users.
+ if (ReductionPHI) {
+ assert(ReductionRoot != NULL && "Need a reduction operation");
+ ReductionRoot->setOperand(0, VectorizedTree);
+ ReductionRoot->setOperand(1, ReductionPHI);
+ } else
+ ReductionRoot->replaceAllUsesWith(VectorizedTree);
+ }
+ return VectorizedTree != 0;
+ }
+
+private:
+
+ /// \brief Calcuate the cost of a reduction.
+ int getReductionCost(TargetTransformInfo *TTI, Value *FirstReducedVal) {
+ Type *ScalarTy = FirstReducedVal->getType();
+ Type *VecTy = VectorType::get(ScalarTy, ReduxWidth);
+
+ int PairwiseRdxCost = TTI->getReductionCost(ReductionOpcode, VecTy, true);
+ int SplittingRdxCost = TTI->getReductionCost(ReductionOpcode, VecTy, false);
+
+ IsPairwiseReduction = PairwiseRdxCost < SplittingRdxCost;
+ int VecReduxCost = IsPairwiseReduction ? PairwiseRdxCost : SplittingRdxCost;
+
+ int ScalarReduxCost =
+ ReduxWidth * TTI->getArithmeticInstrCost(ReductionOpcode, VecTy);
+
+ DEBUG(dbgs() << "SLP: Adding cost " << VecReduxCost - ScalarReduxCost
+ << " for reduction that starts with " << *FirstReducedVal
+ << " (It is a "
+ << (IsPairwiseReduction ? "pairwise" : "splitting")
+ << " reduction)\n");
+
+ return VecReduxCost - ScalarReduxCost;
+ }
+
+ static Value *createBinOp(IRBuilder<> &Builder, unsigned Opcode, Value *L,
+ Value *R, const Twine &Name = "") {
+ if (Opcode == Instruction::FAdd)
+ return Builder.CreateFAdd(L, R, Name);
+ return Builder.CreateBinOp((Instruction::BinaryOps)Opcode, L, R, Name);
+ }
+
+ /// \brief Emit a horizontal reduction of the vectorized value.
+ Value *emitReduction(Value *VectorizedValue, IRBuilder<> &Builder) {
+ assert(VectorizedValue && "Need to have a vectorized tree node");
+ Instruction *ValToReduce = dyn_cast<Instruction>(VectorizedValue);
+ assert(isPowerOf2_32(ReduxWidth) &&
+ "We only handle power-of-two reductions for now");
+
+ Value *TmpVec = ValToReduce;
+ for (unsigned i = ReduxWidth / 2; i != 0; i >>= 1) {
+ if (IsPairwiseReduction) {
+ Value *LeftMask =
+ createRdxShuffleMask(ReduxWidth, i, true, true, Builder);
+ Value *RightMask =
+ createRdxShuffleMask(ReduxWidth, i, true, false, Builder);
+
+ Value *LeftShuf = Builder.CreateShuffleVector(
+ TmpVec, UndefValue::get(TmpVec->getType()), LeftMask, "rdx.shuf.l");
+ Value *RightShuf = Builder.CreateShuffleVector(
+ TmpVec, UndefValue::get(TmpVec->getType()), (RightMask),
+ "rdx.shuf.r");
+ TmpVec = createBinOp(Builder, ReductionOpcode, LeftShuf, RightShuf,
+ "bin.rdx");
+ } else {
+ Value *UpperHalf =
+ createRdxShuffleMask(ReduxWidth, i, false, false, Builder);
+ Value *Shuf = Builder.CreateShuffleVector(
+ TmpVec, UndefValue::get(TmpVec->getType()), UpperHalf, "rdx.shuf");
+ TmpVec = createBinOp(Builder, ReductionOpcode, TmpVec, Shuf, "bin.rdx");
+ }
+ }
+
+ // The result is in the first element of the vector.
+ return Builder.CreateExtractElement(TmpVec, Builder.getInt32(0));
+ }
+};
+
/// \brief Recognize construction of vectors like
/// %ra = insertelement <4 x float> undef, float %s0, i32 0
/// %rb = insertelement <4 x float> %ra, float %s1, i32 1
///
/// Returns true if it matches
///
-static bool findBuildVector(InsertElementInst *IE,
- SmallVectorImpl<Value *> &Ops) {
- if (!isa<UndefValue>(IE->getOperand(0)))
+static bool findBuildVector(InsertElementInst *FirstInsertElem,
+ SmallVectorImpl<Value *> &BuildVector,
+ SmallVectorImpl<Value *> &BuildVectorOpds) {
+ if (!isa<UndefValue>(FirstInsertElem->getOperand(0)))
return false;
+ InsertElementInst *IE = FirstInsertElem;
while (true) {
- Ops.push_back(IE->getOperand(1));
+ BuildVector.push_back(IE);
+ BuildVectorOpds.push_back(IE->getOperand(1));
if (IE->use_empty())
return false;
- InsertElementInst *NextUse = dyn_cast<InsertElementInst>(IE->use_back());
+ InsertElementInst *NextUse = dyn_cast<InsertElementInst>(IE->user_back());
if (!NextUse)
return true;
return false;
}
+static bool PhiTypeSorterFunc(Value *V, Value *V2) {
+ return V->getType() < V2->getType();
+}
+
bool SLPVectorizer::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
bool Changed = false;
SmallVector<Value *, 4> Incoming;
- SmallSet<Instruction *, 16> VisitedInstrs;
+ SmallSet<Value *, 16> VisitedInstrs;
+
+ bool HaveVectorizedPhiNodes = true;
+ while (HaveVectorizedPhiNodes) {
+ HaveVectorizedPhiNodes = false;
+
+ // Collect the incoming values from the PHIs.
+ Incoming.clear();
+ for (BasicBlock::iterator instr = BB->begin(), ie = BB->end(); instr != ie;
+ ++instr) {
+ PHINode *P = dyn_cast<PHINode>(instr);
+ if (!P)
+ break;
- // Collect the incoming values from the PHIs.
- for (BasicBlock::iterator instr = BB->begin(), ie = BB->end(); instr != ie;
- ++instr) {
- PHINode *P = dyn_cast<PHINode>(instr);
+ if (!VisitedInstrs.count(P))
+ Incoming.push_back(P);
+ }
- if (!P)
- break;
+ // Sort by type.
+ std::stable_sort(Incoming.begin(), Incoming.end(), PhiTypeSorterFunc);
- // We may go through BB multiple times so skip the one we have checked.
- if (!VisitedInstrs.insert(instr))
- continue;
+ // Try to vectorize elements base on their type.
+ for (SmallVector<Value *, 4>::iterator IncIt = Incoming.begin(),
+ E = Incoming.end();
+ IncIt != E;) {
- // Stop constructing the list when you reach a different type.
- if (Incoming.size() && P->getType() != Incoming[0]->getType()) {
- if (tryToVectorizeList(Incoming, R)) {
- // We would like to start over since some instructions are deleted
- // and the iterator may become invalid value.
+ // Look for the next elements with the same type.
+ SmallVector<Value *, 4>::iterator SameTypeIt = IncIt;
+ while (SameTypeIt != E &&
+ (*SameTypeIt)->getType() == (*IncIt)->getType()) {
+ VisitedInstrs.insert(*SameTypeIt);
+ ++SameTypeIt;
+ }
+
+ // Try to vectorize them.
+ unsigned NumElts = (SameTypeIt - IncIt);
+ DEBUG(errs() << "SLP: Trying to vectorize starting at PHIs (" << NumElts << ")\n");
+ if (NumElts > 1 &&
+ tryToVectorizeList(ArrayRef<Value *>(IncIt, NumElts), R)) {
+ // Success start over because instructions might have been changed.
+ HaveVectorizedPhiNodes = true;
Changed = true;
- instr = BB->begin();
- ie = BB->end();
+ break;
}
- Incoming.clear();
+ // Start over at the next instruction of a different type (or the end).
+ IncIt = SameTypeIt;
}
-
- Incoming.push_back(P);
}
- if (Incoming.size() > 1)
- Changed |= tryToVectorizeList(Incoming, R);
-
VisitedInstrs.clear();
for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; it++) {
if (!BI)
continue;
- Value *Inst = BI->getOperand(0);
+ // Try to match and vectorize a horizontal reduction.
+ HorizontalReduction HorRdx;
+ if (ShouldVectorizeHor &&
+ HorRdx.matchAssociativeReduction(P, BI, DL) &&
+ HorRdx.tryToReduce(R, TTI)) {
+ Changed = true;
+ it = BB->begin();
+ e = BB->end();
+ continue;
+ }
+
+ Value *Inst = BI->getOperand(0);
if (Inst == P)
Inst = BI->getOperand(1);
Changed = true;
it = BB->begin();
e = BB->end();
+ continue;
}
+
continue;
}
+ // Try to vectorize horizontal reductions feeding into a store.
+ if (ShouldStartVectorizeHorAtStore)
+ if (StoreInst *SI = dyn_cast<StoreInst>(it))
+ if (BinaryOperator *BinOp =
+ dyn_cast<BinaryOperator>(SI->getValueOperand())) {
+ HorizontalReduction HorRdx;
+ if (((HorRdx.matchAssociativeReduction(0, BinOp, DL) &&
+ HorRdx.tryToReduce(R, TTI)) ||
+ tryToVectorize(BinOp, R))) {
+ Changed = true;
+ it = BB->begin();
+ e = BB->end();
+ continue;
+ }
+ }
+
// Try to vectorize trees that start at compare instructions.
if (CmpInst *CI = dyn_cast<CmpInst>(it)) {
if (tryToVectorizePair(CI->getOperand(0), CI->getOperand(1), R)) {
}
// Try to vectorize trees that start at insertelement instructions.
- if (InsertElementInst *IE = dyn_cast<InsertElementInst>(it)) {
- SmallVector<Value *, 8> Ops;
- if (!findBuildVector(IE, Ops))
+ if (InsertElementInst *FirstInsertElem = dyn_cast<InsertElementInst>(it)) {
+ SmallVector<Value *, 16> BuildVector;
+ SmallVector<Value *, 16> BuildVectorOpds;
+ if (!findBuildVector(FirstInsertElem, BuildVector, BuildVectorOpds))
continue;
- if (tryToVectorizeList(Ops, R)) {
+ // Vectorize starting with the build vector operands ignoring the
+ // BuildVector instructions for the purpose of scheduling and user
+ // extraction.
+ if (tryToVectorizeList(BuildVectorOpds, R, BuildVector)) {
Changed = true;
it = BB->begin();
e = BB->end();
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