mirror of
https://github.com/RPCS3/llvm.git
synced 2024-12-22 20:20:03 +00:00
10cc563bfe
This reverts commit r180802 There's ongoing discussion about whether this is the right place to make this transformation. Reverting for now while we figure it out. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180834 91177308-0d34-0410-b5e6-96231b3b80d8
764 lines
29 KiB
C++
764 lines
29 KiB
C++
//===- InstCombineVectorOps.cpp -------------------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements instcombine for ExtractElement, InsertElement and
|
|
// ShuffleVector.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#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 (Constant *C = dyn_cast<Constant>(V)) {
|
|
if (isConstant) return true;
|
|
|
|
// 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;
|
|
}
|
|
Instruction *I = dyn_cast<Instruction>(V);
|
|
if (!I) return false;
|
|
|
|
// Insert element gets simplified to the inserted element or is deleted if
|
|
// this is constant idx extract element and its a constant idx insertelt.
|
|
if (I->getOpcode() == Instruction::InsertElement && isConstant &&
|
|
isa<ConstantInt>(I->getOperand(2)))
|
|
return true;
|
|
if (I->getOpcode() == Instruction::Load && I->hasOneUse())
|
|
return true;
|
|
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I))
|
|
if (BO->hasOneUse() &&
|
|
(CheapToScalarize(BO->getOperand(0), isConstant) ||
|
|
CheapToScalarize(BO->getOperand(1), isConstant)))
|
|
return true;
|
|
if (CmpInst *CI = dyn_cast<CmpInst>(I))
|
|
if (CI->hasOneUse() &&
|
|
(CheapToScalarize(CI->getOperand(0), isConstant) ||
|
|
CheapToScalarize(CI->getOperand(1), isConstant)))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
/// 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 *VTy = cast<VectorType>(V->getType());
|
|
unsigned Width = VTy->getNumElements();
|
|
if (EltNo >= Width) // Out of range access.
|
|
return UndefValue::get(VTy->getElementType());
|
|
|
|
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 (!isa<ConstantInt>(III->getOperand(2)))
|
|
return 0;
|
|
unsigned IIElt = cast<ConstantInt>(III->getOperand(2))->getZExtValue();
|
|
|
|
// If this is an insert to the element we are looking for, return the
|
|
// inserted value.
|
|
if (EltNo == IIElt)
|
|
return III->getOperand(1);
|
|
|
|
// Otherwise, the insertelement doesn't modify the value, recurse on its
|
|
// vector input.
|
|
return FindScalarElement(III->getOperand(0), EltNo);
|
|
}
|
|
|
|
if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(V)) {
|
|
unsigned LHSWidth = SVI->getOperand(0)->getType()->getVectorNumElements();
|
|
int InEl = SVI->getMaskValue(EltNo);
|
|
if (InEl < 0)
|
|
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;
|
|
}
|
|
|
|
// 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();
|
|
}
|
|
|
|
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.
|
|
if (ConstantInt *IdxC = dyn_cast<ConstantInt>(EI.getOperand(1))) {
|
|
unsigned IndexVal = IdxC->getZExtValue();
|
|
unsigned VectorWidth = EI.getVectorOperandType()->getNumElements();
|
|
|
|
// If this is extracting an invalid index, turn this into undef, to avoid
|
|
// crashing the code below.
|
|
if (IndexVal >= VectorWidth)
|
|
return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
|
|
|
|
// This instruction only demands the single element from the input vector.
|
|
// If the input vector has a single use, simplify it based on this use
|
|
// property.
|
|
if (EI.getOperand(0)->hasOneUse() && VectorWidth != 1) {
|
|
APInt UndefElts(VectorWidth, 0);
|
|
APInt DemandedMask(VectorWidth, 0);
|
|
DemandedMask.setBit(IndexVal);
|
|
if (Value *V = SimplifyDemandedVectorElts(EI.getOperand(0),
|
|
DemandedMask, UndefElts)) {
|
|
EI.setOperand(0, V);
|
|
return &EI;
|
|
}
|
|
}
|
|
|
|
if (Value *Elt = FindScalarElement(EI.getOperand(0), IndexVal))
|
|
return ReplaceInstUsesWith(EI, Elt);
|
|
|
|
// If the this extractelement is directly using a bitcast from a vector of
|
|
// 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 (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))) {
|
|
// Push extractelement into predecessor operation if legal and
|
|
// profitable to do so
|
|
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) {
|
|
if (I->hasOneUse() &&
|
|
CheapToScalarize(BO, isa<ConstantInt>(EI.getOperand(1)))) {
|
|
Value *newEI0 =
|
|
Builder->CreateExtractElement(BO->getOperand(0), EI.getOperand(1),
|
|
EI.getName()+".lhs");
|
|
Value *newEI1 =
|
|
Builder->CreateExtractElement(BO->getOperand(1), EI.getOperand(1),
|
|
EI.getName()+".rhs");
|
|
return BinaryOperator::Create(BO->getOpcode(), newEI0, newEI1);
|
|
}
|
|
} else if (InsertElementInst *IE = dyn_cast<InsertElementInst>(I)) {
|
|
// Extracting the inserted element?
|
|
if (IE->getOperand(2) == EI.getOperand(1))
|
|
return ReplaceInstUsesWith(EI, IE->getOperand(1));
|
|
// If the inserted and extracted elements are constants, they must not
|
|
// be the same value, extract from the pre-inserted value instead.
|
|
if (isa<Constant>(IE->getOperand(2)) && isa<Constant>(EI.getOperand(1))) {
|
|
Worklist.AddValue(EI.getOperand(0));
|
|
EI.setOperand(0, IE->getOperand(0));
|
|
return &EI;
|
|
}
|
|
} else if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(I)) {
|
|
// If this is extracting an element from a shufflevector, figure out where
|
|
// it came from and extract from the appropriate input element instead.
|
|
if (ConstantInt *Elt = dyn_cast<ConstantInt>(EI.getOperand(1))) {
|
|
int SrcIdx = SVI->getMaskValue(Elt->getZExtValue());
|
|
Value *Src;
|
|
unsigned LHSWidth =
|
|
SVI->getOperand(0)->getType()->getVectorNumElements();
|
|
|
|
if (SrcIdx < 0)
|
|
return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
|
|
if (SrcIdx < (int)LHSWidth)
|
|
Src = SVI->getOperand(0);
|
|
else {
|
|
SrcIdx -= LHSWidth;
|
|
Src = SVI->getOperand(1);
|
|
}
|
|
Type *Int32Ty = Type::getInt32Ty(EI.getContext());
|
|
return ExtractElementInst::Create(Src,
|
|
ConstantInt::get(Int32Ty,
|
|
SrcIdx, false));
|
|
}
|
|
} 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() && (CI->getOpcode() != Instruction::BitCast)) {
|
|
Value *EE = Builder->CreateExtractElement(CI->getOperand(0),
|
|
EI.getIndexOperand());
|
|
Worklist.AddValue(EE);
|
|
return CastInst::Create(CI->getOpcode(), EE, EI.getType());
|
|
}
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/// CollectSingleShuffleElements - If V is a shuffle of values that ONLY returns
|
|
/// elements from either LHS or RHS, return the shuffle mask and true.
|
|
/// Otherwise, return false.
|
|
static bool CollectSingleShuffleElements(Value *V, Value *LHS, Value *RHS,
|
|
SmallVectorImpl<Constant*> &Mask) {
|
|
assert(V->getType() == LHS->getType() && V->getType() == RHS->getType() &&
|
|
"Invalid CollectSingleShuffleElements");
|
|
unsigned NumElts = cast<VectorType>(V->getType())->getNumElements();
|
|
|
|
if (isa<UndefValue>(V)) {
|
|
Mask.assign(NumElts, UndefValue::get(Type::getInt32Ty(V->getContext())));
|
|
return true;
|
|
}
|
|
|
|
if (V == LHS) {
|
|
for (unsigned i = 0; i != NumElts; ++i)
|
|
Mask.push_back(ConstantInt::get(Type::getInt32Ty(V->getContext()), i));
|
|
return true;
|
|
}
|
|
|
|
if (V == RHS) {
|
|
for (unsigned i = 0; i != NumElts; ++i)
|
|
Mask.push_back(ConstantInt::get(Type::getInt32Ty(V->getContext()),
|
|
i+NumElts));
|
|
return true;
|
|
}
|
|
|
|
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);
|
|
Value *ScalarOp = IEI->getOperand(1);
|
|
Value *IdxOp = IEI->getOperand(2);
|
|
|
|
if (!isa<ConstantInt>(IdxOp))
|
|
return false;
|
|
unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue();
|
|
|
|
if (isa<UndefValue>(ScalarOp)) { // inserting undef into vector.
|
|
// Okay, we can handle this if the vector we are insertinting into is
|
|
// transitively ok.
|
|
if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask)) {
|
|
// If so, update the mask to reflect the inserted undef.
|
|
Mask[InsertedIdx] = UndefValue::get(Type::getInt32Ty(V->getContext()));
|
|
return true;
|
|
}
|
|
} else if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)){
|
|
if (isa<ConstantInt>(EI->getOperand(1)) &&
|
|
EI->getOperand(0)->getType() == V->getType()) {
|
|
unsigned ExtractedIdx =
|
|
cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
|
|
|
|
// This must be extracting from either LHS or RHS.
|
|
if (EI->getOperand(0) == LHS || EI->getOperand(0) == RHS) {
|
|
// Okay, we can handle this if the vector we are insertinting into is
|
|
// transitively ok.
|
|
if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask)) {
|
|
// If so, update the mask to reflect the inserted value.
|
|
if (EI->getOperand(0) == LHS) {
|
|
Mask[InsertedIdx % NumElts] =
|
|
ConstantInt::get(Type::getInt32Ty(V->getContext()),
|
|
ExtractedIdx);
|
|
} else {
|
|
assert(EI->getOperand(0) == RHS);
|
|
Mask[InsertedIdx % NumElts] =
|
|
ConstantInt::get(Type::getInt32Ty(V->getContext()),
|
|
ExtractedIdx+NumElts);
|
|
}
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
// TODO: Handle shufflevector here!
|
|
|
|
return false;
|
|
}
|
|
|
|
/// 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, SmallVectorImpl<Constant*> &Mask,
|
|
Value *&RHS) {
|
|
assert(V->getType()->isVectorTy() &&
|
|
(RHS == 0 || V->getType() == RHS->getType()) &&
|
|
"Invalid shuffle!");
|
|
unsigned NumElts = cast<VectorType>(V->getType())->getNumElements();
|
|
|
|
if (isa<UndefValue>(V)) {
|
|
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);
|
|
Value *ScalarOp = IEI->getOperand(1);
|
|
Value *IdxOp = IEI->getOperand(2);
|
|
|
|
if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)) {
|
|
if (isa<ConstantInt>(EI->getOperand(1)) && isa<ConstantInt>(IdxOp) &&
|
|
EI->getOperand(0)->getType() == V->getType()) {
|
|
unsigned ExtractedIdx =
|
|
cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
|
|
unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue();
|
|
|
|
// Either the extracted from or inserted into vector must be RHSVec,
|
|
// otherwise we'd end up with a shuffle of three inputs.
|
|
if (EI->getOperand(0) == RHS || RHS == 0) {
|
|
RHS = EI->getOperand(0);
|
|
Value *V = CollectShuffleElements(VecOp, Mask, RHS);
|
|
Mask[InsertedIdx % NumElts] =
|
|
ConstantInt::get(Type::getInt32Ty(V->getContext()),
|
|
NumElts+ExtractedIdx);
|
|
return V;
|
|
}
|
|
|
|
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)
|
|
Mask[i] = ConstantInt::get(Type::getInt32Ty(V->getContext()),
|
|
NumElts+i);
|
|
}
|
|
return V;
|
|
}
|
|
|
|
// If this insertelement is a chain that comes from exactly these two
|
|
// vectors, return the vector and the effective shuffle.
|
|
if (CollectSingleShuffleElements(IEI, EI->getOperand(0), RHS, Mask))
|
|
return EI->getOperand(0);
|
|
}
|
|
}
|
|
}
|
|
// TODO: Handle shufflevector here!
|
|
|
|
// Otherwise, can't do anything fancy. Return an identity vector.
|
|
for (unsigned i = 0; i != NumElts; ++i)
|
|
Mask.push_back(ConstantInt::get(Type::getInt32Ty(V->getContext()), i));
|
|
return V;
|
|
}
|
|
|
|
Instruction *InstCombiner::visitInsertElementInst(InsertElementInst &IE) {
|
|
Value *VecOp = IE.getOperand(0);
|
|
Value *ScalarOp = IE.getOperand(1);
|
|
Value *IdxOp = IE.getOperand(2);
|
|
|
|
// Inserting an undef or into an undefined place, remove this.
|
|
if (isa<UndefValue>(ScalarOp) || isa<UndefValue>(IdxOp))
|
|
ReplaceInstUsesWith(IE, VecOp);
|
|
|
|
// If the inserted element was extracted from some other vector, and if the
|
|
// indexes are constant, try to turn this into a shufflevector operation.
|
|
if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)) {
|
|
if (isa<ConstantInt>(EI->getOperand(1)) && isa<ConstantInt>(IdxOp) &&
|
|
EI->getOperand(0)->getType() == IE.getType()) {
|
|
unsigned NumVectorElts = IE.getType()->getNumElements();
|
|
unsigned ExtractedIdx =
|
|
cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
|
|
unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue();
|
|
|
|
if (ExtractedIdx >= NumVectorElts) // Out of range extract.
|
|
return ReplaceInstUsesWith(IE, VecOp);
|
|
|
|
if (InsertedIdx >= NumVectorElts) // Out of range insert.
|
|
return ReplaceInstUsesWith(IE, UndefValue::get(IE.getType()));
|
|
|
|
// If we are extracting a value from a vector, then inserting it right
|
|
// back into the same place, just use the input vector.
|
|
if (EI->getOperand(0) == VecOp && ExtractedIdx == InsertedIdx)
|
|
return ReplaceInstUsesWith(IE, VecOp);
|
|
|
|
// 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())) {
|
|
SmallVector<Constant*, 16> Mask;
|
|
Value *RHS = 0;
|
|
Value *LHS = CollectShuffleElements(&IE, Mask, RHS);
|
|
if (RHS == 0) RHS = UndefValue::get(LHS->getType());
|
|
// We now have a shuffle of LHS, RHS, Mask.
|
|
return new ShuffleVectorInst(LHS, RHS, ConstantVector::get(Mask));
|
|
}
|
|
}
|
|
}
|
|
|
|
unsigned VWidth = cast<VectorType>(VecOp->getType())->getNumElements();
|
|
APInt UndefElts(VWidth, 0);
|
|
APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
|
|
if (Value *V = SimplifyDemandedVectorElts(&IE, AllOnesEltMask, UndefElts)) {
|
|
if (V != &IE)
|
|
return ReplaceInstUsesWith(IE, V);
|
|
return &IE;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
|
|
Value *LHS = SVI.getOperand(0);
|
|
Value *RHS = SVI.getOperand(1);
|
|
SmallVector<int, 16> Mask = SVI.getShuffleMask();
|
|
|
|
bool MadeChange = false;
|
|
|
|
// Undefined shuffle mask -> undefined value.
|
|
if (isa<UndefValue>(SVI.getOperand(2)))
|
|
return ReplaceInstUsesWith(SVI, UndefValue::get(SVI.getType()));
|
|
|
|
unsigned VWidth = cast<VectorType>(SVI.getType())->getNumElements();
|
|
|
|
APInt UndefElts(VWidth, 0);
|
|
APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
|
|
if (Value *V = SimplifyDemandedVectorElts(&SVI, AllOnesEltMask, UndefElts)) {
|
|
if (V != &SVI)
|
|
return ReplaceInstUsesWith(SVI, V);
|
|
LHS = SVI.getOperand(0);
|
|
RHS = SVI.getOperand(1);
|
|
MadeChange = true;
|
|
}
|
|
|
|
unsigned LHSWidth = cast<VectorType>(LHS->getType())->getNumElements();
|
|
|
|
// Canonicalize shuffle(x ,x,mask) -> shuffle(x, undef,mask')
|
|
// Canonicalize shuffle(undef,x,mask) -> shuffle(x, undef,mask').
|
|
if (LHS == RHS || isa<UndefValue>(LHS)) {
|
|
if (isa<UndefValue>(LHS) && LHS == RHS) {
|
|
// shuffle(undef,undef,mask) -> undef.
|
|
Value* result = (VWidth == LHSWidth)
|
|
? LHS : UndefValue::get(SVI.getType());
|
|
return ReplaceInstUsesWith(SVI, result);
|
|
}
|
|
|
|
// Remap any references to RHS to use LHS.
|
|
SmallVector<Constant*, 16> Elts;
|
|
for (unsigned i = 0, e = LHSWidth; i != VWidth; ++i) {
|
|
if (Mask[i] < 0) {
|
|
Elts.push_back(UndefValue::get(Type::getInt32Ty(SVI.getContext())));
|
|
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));
|
|
SVI.setOperand(1, UndefValue::get(RHS->getType()));
|
|
SVI.setOperand(2, ConstantVector::get(Elts));
|
|
LHS = SVI.getOperand(0);
|
|
RHS = SVI.getOperand(1);
|
|
MadeChange = true;
|
|
}
|
|
|
|
if (VWidth == LHSWidth) {
|
|
// Analyze the shuffle, are the LHS or RHS and identity shuffles?
|
|
bool isLHSID = true, isRHSID = true;
|
|
|
|
for (unsigned i = 0, e = Mask.size(); i != e; ++i) {
|
|
if (Mask[i] < 0) continue; // Ignore undef values.
|
|
// Is this an identity shuffle of the LHS value?
|
|
isLHSID &= (Mask[i] == (int)i);
|
|
|
|
// Is this an identity shuffle of the RHS value?
|
|
isRHSID &= (Mask[i]-e == i);
|
|
}
|
|
|
|
// Eliminate identity shuffles.
|
|
if (isLHSID) return ReplaceInstUsesWith(SVI, LHS);
|
|
if (isRHSID) return ReplaceInstUsesWith(SVI, RHS);
|
|
}
|
|
|
|
// If the LHS is a shufflevector itself, see if we can combine it with this
|
|
// one without producing an unusual shuffle.
|
|
// Cases that might be simplified:
|
|
// 1.
|
|
// x1=shuffle(v1,v2,mask1)
|
|
// x=shuffle(x1,undef,mask)
|
|
// ==>
|
|
// x=shuffle(v1,undef,newMask)
|
|
// newMask[i] = (mask[i] < x1.size()) ? mask1[mask[i]] : -1
|
|
// 2.
|
|
// x1=shuffle(v1,undef,mask1)
|
|
// x=shuffle(x1,x2,mask)
|
|
// where v1.size() == mask1.size()
|
|
// ==>
|
|
// x=shuffle(v1,x2,newMask)
|
|
// newMask[i] = (mask[i] < x1.size()) ? mask1[mask[i]] : mask[i]
|
|
// 3.
|
|
// x2=shuffle(v2,undef,mask2)
|
|
// x=shuffle(x1,x2,mask)
|
|
// where v2.size() == mask2.size()
|
|
// ==>
|
|
// x=shuffle(x1,v2,newMask)
|
|
// newMask[i] = (mask[i] < x1.size())
|
|
// ? mask[i] : mask2[mask[i]-x1.size()]+x1.size()
|
|
// 4.
|
|
// x1=shuffle(v1,undef,mask1)
|
|
// x2=shuffle(v2,undef,mask2)
|
|
// x=shuffle(x1,x2,mask)
|
|
// where v1.size() == v2.size()
|
|
// ==>
|
|
// x=shuffle(v1,v2,newMask)
|
|
// newMask[i] = (mask[i] < x1.size())
|
|
// ? mask1[mask[i]] : mask2[mask[i]-x1.size()]+v1.size()
|
|
//
|
|
// Here we are really conservative:
|
|
// we are absolutely afraid of producing a shuffle mask not in the input
|
|
// program, because the code gen may not be smart enough to turn a merged
|
|
// shuffle into two specific shuffles: it may produce worse code. As such,
|
|
// we only merge two shuffles if the result is either a splat or one of the
|
|
// input shuffle masks. In this case, merging the shuffles just removes
|
|
// one instruction, which we know is safe. This is good for things like
|
|
// turning: (splat(splat)) -> splat, or
|
|
// merge(V[0..n], V[n+1..2n]) -> V[0..2n]
|
|
ShuffleVectorInst* LHSShuffle = dyn_cast<ShuffleVectorInst>(LHS);
|
|
ShuffleVectorInst* RHSShuffle = dyn_cast<ShuffleVectorInst>(RHS);
|
|
if (LHSShuffle)
|
|
if (!isa<UndefValue>(LHSShuffle->getOperand(1)) && !isa<UndefValue>(RHS))
|
|
LHSShuffle = NULL;
|
|
if (RHSShuffle)
|
|
if (!isa<UndefValue>(RHSShuffle->getOperand(1)))
|
|
RHSShuffle = NULL;
|
|
if (!LHSShuffle && !RHSShuffle)
|
|
return MadeChange ? &SVI : 0;
|
|
|
|
Value* LHSOp0 = NULL;
|
|
Value* LHSOp1 = NULL;
|
|
Value* RHSOp0 = NULL;
|
|
unsigned LHSOp0Width = 0;
|
|
unsigned RHSOp0Width = 0;
|
|
if (LHSShuffle) {
|
|
LHSOp0 = LHSShuffle->getOperand(0);
|
|
LHSOp1 = LHSShuffle->getOperand(1);
|
|
LHSOp0Width = cast<VectorType>(LHSOp0->getType())->getNumElements();
|
|
}
|
|
if (RHSShuffle) {
|
|
RHSOp0 = RHSShuffle->getOperand(0);
|
|
RHSOp0Width = cast<VectorType>(RHSOp0->getType())->getNumElements();
|
|
}
|
|
Value* newLHS = LHS;
|
|
Value* newRHS = RHS;
|
|
if (LHSShuffle) {
|
|
// case 1
|
|
if (isa<UndefValue>(RHS)) {
|
|
newLHS = LHSOp0;
|
|
newRHS = LHSOp1;
|
|
}
|
|
// case 2 or 4
|
|
else if (LHSOp0Width == LHSWidth) {
|
|
newLHS = LHSOp0;
|
|
}
|
|
}
|
|
// case 3 or 4
|
|
if (RHSShuffle && RHSOp0Width == LHSWidth) {
|
|
newRHS = RHSOp0;
|
|
}
|
|
// case 4
|
|
if (LHSOp0 == RHSOp0) {
|
|
newLHS = LHSOp0;
|
|
newRHS = NULL;
|
|
}
|
|
|
|
if (newLHS == LHS && newRHS == RHS)
|
|
return MadeChange ? &SVI : 0;
|
|
|
|
SmallVector<int, 16> LHSMask;
|
|
SmallVector<int, 16> RHSMask;
|
|
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;
|
|
int SplatElt = -1;
|
|
// Create a new mask for the new ShuffleVectorInst so that the new
|
|
// ShuffleVectorInst is equivalent to the original one.
|
|
for (unsigned i = 0; i < VWidth; ++i) {
|
|
int eltMask;
|
|
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) {
|
|
eltMask = LHSMask[Mask[i]];
|
|
// If the value selected is an undef value, explicitly specify it
|
|
// with a -1 mask value.
|
|
if (eltMask >= (int)LHSOp0Width && isa<UndefValue>(LHSOp1))
|
|
eltMask = -1;
|
|
} else
|
|
eltMask = Mask[i];
|
|
} else {
|
|
// This element is from right hand side vector operand
|
|
//
|
|
// If the value selected is an undef value, explicitly specify it
|
|
// with a -1 mask value. (case 1)
|
|
if (isa<UndefValue>(RHS))
|
|
eltMask = -1;
|
|
// If RHS is going to be replaced (case 3 or 4), calculate the
|
|
// new mask value for the element.
|
|
else if (newRHS != RHS) {
|
|
eltMask = RHSMask[Mask[i]-LHSWidth];
|
|
// If the value selected is an undef value, explicitly specify it
|
|
// with a -1 mask value.
|
|
if (eltMask >= (int)RHSOp0Width) {
|
|
assert(isa<UndefValue>(RHSShuffle->getOperand(1))
|
|
&& "should have been check above");
|
|
eltMask = -1;
|
|
}
|
|
} 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 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;
|
|
}
|
|
|
|
// Check if this could still be a splat.
|
|
if (eltMask >= 0) {
|
|
if (SplatElt >= 0 && SplatElt != eltMask)
|
|
isSplat = false;
|
|
SplatElt = eltMask;
|
|
}
|
|
|
|
newMask.push_back(eltMask);
|
|
}
|
|
|
|
// If the result mask is equal to one of the original shuffle masks,
|
|
// or is a splat, do the replacement.
|
|
if (isSplat || newMask == LHSMask || newMask == RHSMask || newMask == Mask) {
|
|
SmallVector<Constant*, 16> Elts;
|
|
Type *Int32Ty = Type::getInt32Ty(SVI.getContext());
|
|
for (unsigned i = 0, e = newMask.size(); i != e; ++i) {
|
|
if (newMask[i] < 0) {
|
|
Elts.push_back(UndefValue::get(Int32Ty));
|
|
} else {
|
|
Elts.push_back(ConstantInt::get(Int32Ty, newMask[i]));
|
|
}
|
|
}
|
|
if (newRHS == NULL)
|
|
newRHS = UndefValue::get(newLHS->getType());
|
|
return new ShuffleVectorInst(newLHS, newRHS, ConstantVector::get(Elts));
|
|
}
|
|
|
|
return MadeChange ? &SVI : 0;
|
|
}
|