//===----------------------------------------------------------------------===//
#include "InstCombine.h"
+#include "llvm/Support/PatternMatch.h"
using namespace llvm;
+using namespace PatternMatch;
/// CheapToScalarize - Return true if the value is cheaper to scalarize than it
/// is to leave as a vector operation. isConstant indicates whether we're
/// extracting one known element. If false we're extracting a variable index.
static bool CheapToScalarize(Value *V, bool isConstant) {
- if (isa<ConstantAggregateZero>(V))
- return true;
- if (ConstantVector *C = dyn_cast<ConstantVector>(V)) {
+ if (Constant *C = dyn_cast<Constant>(V)) {
if (isConstant) return true;
- // If all elts are the same, we can extract.
- Constant *Op0 = C->getOperand(0);
- for (unsigned i = 1; i < C->getNumOperands(); ++i)
- if (C->getOperand(i) != Op0)
+
+ // If all elts are the same, we can extract it and use any of the values.
+ Constant *Op0 = C->getAggregateElement(0U);
+ for (unsigned i = 1, e = V->getType()->getVectorNumElements(); i != e; ++i)
+ if (C->getAggregateElement(i) != Op0)
return false;
return true;
}
return false;
}
-/// getShuffleMask - Read and decode a shufflevector mask.
-/// Turn undef elements into negative values.
-static SmallVector<int, 16> getShuffleMask(const ShuffleVectorInst *SVI) {
- unsigned NElts = SVI->getType()->getNumElements();
- if (isa<ConstantAggregateZero>(SVI->getOperand(2)))
- return SmallVector<int, 16>(NElts, 0);
- if (isa<UndefValue>(SVI->getOperand(2)))
- return SmallVector<int, 16>(NElts, -1);
-
- SmallVector<int, 16> Result;
- const ConstantVector *CP = cast<ConstantVector>(SVI->getOperand(2));
- for (User::const_op_iterator i = CP->op_begin(), e = CP->op_end(); i!=e; ++i)
- if (isa<UndefValue>(*i))
- Result.push_back(-1); // undef
- else
- Result.push_back(cast<ConstantInt>(*i)->getZExtValue());
- return Result;
-}
-
/// FindScalarElement - Given a vector and an element number, see if the scalar
/// value is already around as a register, for example if it were inserted then
/// extracted from the vector.
static Value *FindScalarElement(Value *V, unsigned EltNo) {
assert(V->getType()->isVectorTy() && "Not looking at a vector?");
- VectorType *PTy = cast<VectorType>(V->getType());
- unsigned Width = PTy->getNumElements();
+ VectorType *VTy = cast<VectorType>(V->getType());
+ unsigned Width = VTy->getNumElements();
if (EltNo >= Width) // Out of range access.
- return UndefValue::get(PTy->getElementType());
+ return UndefValue::get(VTy->getElementType());
- if (isa<UndefValue>(V))
- return UndefValue::get(PTy->getElementType());
- if (isa<ConstantAggregateZero>(V))
- return Constant::getNullValue(PTy->getElementType());
- if (ConstantVector *CP = dyn_cast<ConstantVector>(V))
- return CP->getOperand(EltNo);
+ if (Constant *C = dyn_cast<Constant>(V))
+ return C->getAggregateElement(EltNo);
if (InsertElementInst *III = dyn_cast<InsertElementInst>(V)) {
// If this is an insert to a variable element, we don't know what it is.
}
if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(V)) {
- unsigned LHSWidth =
- cast<VectorType>(SVI->getOperand(0)->getType())->getNumElements();
+ unsigned LHSWidth = SVI->getOperand(0)->getType()->getVectorNumElements();
int InEl = SVI->getMaskValue(EltNo);
if (InEl < 0)
- return UndefValue::get(PTy->getElementType());
+ return UndefValue::get(VTy->getElementType());
if (InEl < (int)LHSWidth)
return FindScalarElement(SVI->getOperand(0), InEl);
return FindScalarElement(SVI->getOperand(1), InEl - LHSWidth);
}
+ // Extract a value from a vector add operation with a constant zero.
+ Value *Val = 0; Constant *Con = 0;
+ if (match(V, m_Add(m_Value(Val), m_Constant(Con)))) {
+ if (Con->getAggregateElement(EltNo)->isNullValue())
+ return FindScalarElement(Val, EltNo);
+ }
+
// Otherwise, we don't know.
return 0;
}
-Instruction *InstCombiner::visitExtractElementInst(ExtractElementInst &EI) {
- // If vector val is undef, replace extract with scalar undef.
- if (isa<UndefValue>(EI.getOperand(0)))
- return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
-
- // If vector val is constant 0, replace extract with scalar 0.
- if (isa<ConstantAggregateZero>(EI.getOperand(0)))
- return ReplaceInstUsesWith(EI, Constant::getNullValue(EI.getType()));
-
- if (ConstantVector *C = dyn_cast<ConstantVector>(EI.getOperand(0))) {
- // If vector val is constant with all elements the same, replace EI with
- // that element. When the elements are not identical, we cannot replace yet
- // (we do that below, but only when the index is constant).
- Constant *op0 = C->getOperand(0);
- for (unsigned i = 1; i != C->getNumOperands(); ++i)
- if (C->getOperand(i) != op0) {
- op0 = 0;
- break;
+// If we have a PHI node with a vector type that has only 2 uses: feed
+// itself and be an operand of extractelemnt at a constant location,
+// try to replace the PHI of the vector type with a PHI of a scalar type
+Instruction *InstCombiner::scalarizePHI(ExtractElementInst &EI, PHINode *PN) {
+ // Verify that the PHI node has exactly 2 uses. Otherwise return NULL.
+ if (!PN->hasNUses(2))
+ return NULL;
+
+ // If so, it's known at this point that one operand is PHI and the other is
+ // an extractelement node. Find the PHI user that is not the extractelement
+ // node.
+ Value::use_iterator iu = PN->use_begin();
+ Instruction *PHIUser = dyn_cast<Instruction>(*iu);
+ if (PHIUser == cast<Instruction>(&EI))
+ PHIUser = cast<Instruction>(*(++iu));
+
+ // Verify that this PHI user has one use, which is the PHI itself,
+ // and that it is a binary operation which is cheap to scalarize.
+ // otherwise return NULL.
+ if (!PHIUser->hasOneUse() || !(PHIUser->use_back() == PN) ||
+ !(isa<BinaryOperator>(PHIUser)) ||
+ !CheapToScalarize(PHIUser, true))
+ return NULL;
+
+ // Create a scalar PHI node that will replace the vector PHI node
+ // just before the current PHI node.
+ PHINode * scalarPHI = cast<PHINode>(
+ InsertNewInstWith(PHINode::Create(EI.getType(),
+ PN->getNumIncomingValues(), ""), *PN));
+ // Scalarize each PHI operand.
+ for (unsigned i=0; i < PN->getNumIncomingValues(); i++) {
+ Value *PHIInVal = PN->getIncomingValue(i);
+ BasicBlock *inBB = PN->getIncomingBlock(i);
+ Value *Elt = EI.getIndexOperand();
+ // If the operand is the PHI induction variable:
+ if (PHIInVal == PHIUser) {
+ // Scalarize the binary operation. Its first operand is the
+ // scalar PHI and the second operand is extracted from the other
+ // vector operand.
+ BinaryOperator *B0 = cast<BinaryOperator>(PHIUser);
+ unsigned opId = (B0->getOperand(0) == PN) ? 1: 0;
+ Value *Op = Builder->CreateExtractElement(
+ B0->getOperand(opId), Elt, B0->getOperand(opId)->getName()+".Elt");
+ Value *newPHIUser = InsertNewInstWith(
+ BinaryOperator::Create(B0->getOpcode(), scalarPHI,Op),
+ *B0);
+ scalarPHI->addIncoming(newPHIUser, inBB);
+ } else {
+ // Scalarize PHI input:
+ Instruction *newEI =
+ ExtractElementInst::Create(PHIInVal, Elt, "");
+ // Insert the new instruction into the predecessor basic block.
+ Instruction *pos = dyn_cast<Instruction>(PHIInVal);
+ BasicBlock::iterator InsertPos;
+ if (pos && !isa<PHINode>(pos)) {
+ InsertPos = pos;
+ ++InsertPos;
+ } else {
+ InsertPos = inBB->getFirstInsertionPt();
}
- if (op0)
- return ReplaceInstUsesWith(EI, op0);
+
+ InsertNewInstWith(newEI, *InsertPos);
+
+ scalarPHI->addIncoming(newEI, inBB);
+ }
}
+ return ReplaceInstUsesWith(EI, scalarPHI);
+}
+
+Instruction *InstCombiner::visitExtractElementInst(ExtractElementInst &EI) {
+ // If vector val is constant with all elements the same, replace EI with
+ // that element. We handle a known element # below.
+ if (Constant *C = dyn_cast<Constant>(EI.getOperand(0)))
+ if (CheapToScalarize(C, false))
+ return ReplaceInstUsesWith(EI, C->getAggregateElement(0U));
// If extracting a specified index from the vector, see if we can recursively
// find a previously computed scalar that was inserted into the vector.
// the same number of elements, see if we can find the source element from
// it. In this case, we will end up needing to bitcast the scalars.
if (BitCastInst *BCI = dyn_cast<BitCastInst>(EI.getOperand(0))) {
- if (VectorType *VT =
- dyn_cast<VectorType>(BCI->getOperand(0)->getType()))
+ if (VectorType *VT = dyn_cast<VectorType>(BCI->getOperand(0)->getType()))
if (VT->getNumElements() == VectorWidth)
if (Value *Elt = FindScalarElement(BCI->getOperand(0), IndexVal))
return new BitCastInst(Elt, EI.getType());
}
+
+ // If there's a vector PHI feeding a scalar use through this extractelement
+ // instruction, try to scalarize the PHI.
+ if (PHINode *PN = dyn_cast<PHINode>(EI.getOperand(0))) {
+ Instruction *scalarPHI = scalarizePHI(EI, PN);
+ if (scalarPHI)
+ return (scalarPHI);
+ }
}
if (Instruction *I = dyn_cast<Instruction>(EI.getOperand(0))) {
int SrcIdx = SVI->getMaskValue(Elt->getZExtValue());
Value *Src;
unsigned LHSWidth =
- cast<VectorType>(SVI->getOperand(0)->getType())->getNumElements();
+ SVI->getOperand(0)->getType()->getVectorNumElements();
if (SrcIdx < 0)
return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
} else if (CastInst *CI = dyn_cast<CastInst>(I)) {
// Canonicalize extractelement(cast) -> cast(extractelement)
// bitcasts can change the number of vector elements and they cost nothing
- if (CI->hasOneUse() && EI.hasOneUse() &&
- (CI->getOpcode() != Instruction::BitCast)) {
+ if (CI->hasOneUse() && (CI->getOpcode() != Instruction::BitCast)) {
Value *EE = Builder->CreateExtractElement(CI->getOperand(0),
EI.getIndexOperand());
+ Worklist.AddValue(EE);
return CastInst::Create(CI->getOpcode(), EE, EI.getType());
}
}
/// elements from either LHS or RHS, return the shuffle mask and true.
/// Otherwise, return false.
static bool CollectSingleShuffleElements(Value *V, Value *LHS, Value *RHS,
- std::vector<Constant*> &Mask) {
+ SmallVectorImpl<Constant*> &Mask) {
assert(V->getType() == LHS->getType() && V->getType() == RHS->getType() &&
"Invalid CollectSingleShuffleElements");
unsigned NumElts = cast<VectorType>(V->getType())->getNumElements();
/// CollectShuffleElements - We are building a shuffle of V, using RHS as the
/// RHS of the shuffle instruction, if it is not null. Return a shuffle mask
/// that computes V and the LHS value of the shuffle.
-static Value *CollectShuffleElements(Value *V, std::vector<Constant*> &Mask,
+static Value *CollectShuffleElements(Value *V, SmallVectorImpl<Constant*> &Mask,
Value *&RHS) {
assert(V->getType()->isVectorTy() &&
(RHS == 0 || V->getType() == RHS->getType()) &&
Mask.assign(NumElts, UndefValue::get(Type::getInt32Ty(V->getContext())));
return V;
}
-
+
if (isa<ConstantAggregateZero>(V)) {
Mask.assign(NumElts, ConstantInt::get(Type::getInt32Ty(V->getContext()),0));
return V;
}
-
+
if (InsertElementInst *IEI = dyn_cast<InsertElementInst>(V)) {
// If this is an insert of an extract from some other vector, include it.
Value *VecOp = IEI->getOperand(0);
if (VecOp == RHS) {
Value *V = CollectShuffleElements(EI->getOperand(0), Mask, RHS);
+ // Update Mask to reflect that `ScalarOp' has been inserted at
+ // position `InsertedIdx' within the vector returned by IEI.
+ Mask[InsertedIdx % NumElts] = Mask[ExtractedIdx];
+
// Everything but the extracted element is replaced with the RHS.
for (unsigned i = 0; i != NumElts; ++i) {
if (i != InsertedIdx)
// If this insertelement isn't used by some other insertelement, turn it
// (and any insertelements it points to), into one big shuffle.
if (!IE.hasOneUse() || !isa<InsertElementInst>(IE.use_back())) {
- std::vector<Constant*> Mask;
+ SmallVector<Constant*, 16> Mask;
Value *RHS = 0;
Value *LHS = CollectShuffleElements(&IE, Mask, RHS);
if (RHS == 0) RHS = UndefValue::get(LHS->getType());
Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
Value *LHS = SVI.getOperand(0);
Value *RHS = SVI.getOperand(1);
- SmallVector<int, 16> Mask = getShuffleMask(&SVI);
+ SmallVector<int, 16> Mask = SVI.getShuffleMask();
bool MadeChange = false;
}
// Remap any references to RHS to use LHS.
- std::vector<Constant*> Elts;
+ SmallVector<Constant*, 16> Elts;
for (unsigned i = 0, e = LHSWidth; i != VWidth; ++i) {
- if (Mask[i] < 0)
+ if (Mask[i] < 0) {
Elts.push_back(UndefValue::get(Type::getInt32Ty(SVI.getContext())));
- else {
- if ((Mask[i] >= (int)e && isa<UndefValue>(RHS)) ||
- (Mask[i] < (int)e && isa<UndefValue>(LHS))) {
- Mask[i] = -1; // Turn into undef.
- Elts.push_back(UndefValue::get(Type::getInt32Ty(SVI.getContext())));
- } else {
- Mask[i] = Mask[i] % e; // Force to LHS.
- Elts.push_back(ConstantInt::get(Type::getInt32Ty(SVI.getContext()),
- Mask[i]));
- }
+ continue;
+ }
+
+ if ((Mask[i] >= (int)e && isa<UndefValue>(RHS)) ||
+ (Mask[i] < (int)e && isa<UndefValue>(LHS))) {
+ Mask[i] = -1; // Turn into undef.
+ Elts.push_back(UndefValue::get(Type::getInt32Ty(SVI.getContext())));
+ } else {
+ Mask[i] = Mask[i] % e; // Force to LHS.
+ Elts.push_back(ConstantInt::get(Type::getInt32Ty(SVI.getContext()),
+ Mask[i]));
}
}
SVI.setOperand(0, SVI.getOperand(1));
SmallVector<int, 16> LHSMask;
SmallVector<int, 16> RHSMask;
- if (newLHS != LHS) {
- LHSMask = getShuffleMask(LHSShuffle);
- }
- if (RHSShuffle && newRHS != RHS) {
- RHSMask = getShuffleMask(RHSShuffle);
- }
+ if (newLHS != LHS)
+ LHSMask = LHSShuffle->getShuffleMask();
+ if (RHSShuffle && newRHS != RHS)
+ RHSMask = RHSShuffle->getShuffleMask();
+
unsigned newLHSWidth = (newLHS != LHS) ? LHSOp0Width : LHSWidth;
SmallVector<int, 16> newMask;
bool isSplat = true;
// ShuffleVectorInst is equivalent to the original one.
for (unsigned i = 0; i < VWidth; ++i) {
int eltMask;
- if (Mask[i] == -1) {
+ if (Mask[i] < 0) {
// This element is an undef value.
eltMask = -1;
} else if (Mask[i] < (int)LHSWidth) {
// This element is from left hand side vector operand.
- //
+ //
// If LHS is going to be replaced (case 1, 2, or 4), calculate the
// new mask value for the element.
if (newLHS != LHS) {
// with a -1 mask value.
if (eltMask >= (int)LHSOp0Width && isa<UndefValue>(LHSOp1))
eltMask = -1;
- }
- else
+ } else
eltMask = Mask[i];
} else {
// This element is from right hand side vector operand
&& "should have been check above");
eltMask = -1;
}
- }
- else
+ } else
eltMask = Mask[i]-LHSWidth;
// If LHS's width is changed, shift the mask value accordingly.
// If newRHS == NULL, i.e. LHSOp0 == RHSOp0, we want to remap any
- // references to RHSOp0 to LHSOp0, so we don't need to shift the mask.
- if (eltMask >= 0 && newRHS != NULL)
+ // references from RHSOp0 to LHSOp0, so we don't need to shift the mask.
+ // If newRHS == newLHS, we want to remap any references from newRHS to
+ // newLHS so that we can properly identify splats that may occur due to
+ // obfuscation accross the two vectors.
+ if (eltMask >= 0 && newRHS != NULL && newLHS != newRHS)
eltMask += newLHSWidth;
}
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