mirror of
https://github.com/RPCS3/llvm.git
synced 2024-12-22 12:08:33 +00:00
d096e43858
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247154 91177308-0d34-0410-b5e6-96231b3b80d8
1185 lines
46 KiB
C++
1185 lines
46 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 "InstCombineInternal.h"
|
|
#include "llvm/ADT/DenseMap.h"
|
|
#include "llvm/Analysis/InstructionSimplify.h"
|
|
#include "llvm/Analysis/VectorUtils.h"
|
|
#include "llvm/IR/PatternMatch.h"
|
|
using namespace llvm;
|
|
using namespace PatternMatch;
|
|
|
|
#define DEBUG_TYPE "instcombine"
|
|
|
|
/// 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.
|
|
if (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;
|
|
}
|
|
|
|
// If we have a PHI node with a vector type that has only 2 uses: feed
|
|
// itself and be an operand of extractelement 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 nullptr;
|
|
|
|
// 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.
|
|
auto iu = PN->user_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->user_back() == PN) ||
|
|
!(isa<BinaryOperator>(PHIUser)) || !CheapToScalarize(PHIUser, true))
|
|
return nullptr;
|
|
|
|
// 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 = InsertNewInstWith(
|
|
ExtractElementInst::Create(B0->getOperand(opId), Elt,
|
|
B0->getOperand(opId)->getName() + ".Elt"),
|
|
*B0);
|
|
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 (Value *V = SimplifyExtractElementInst(
|
|
EI.getVectorOperand(), EI.getIndexOperand(), DL, TLI, DT, AC))
|
|
return ReplaceInstUsesWith(EI, V);
|
|
|
|
// 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();
|
|
|
|
// InstSimplify handles cases where the index is invalid.
|
|
assert(IndexVal < VectorWidth);
|
|
|
|
// 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 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());
|
|
}
|
|
} else if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
|
|
if (SI->hasOneUse()) {
|
|
// TODO: For a select on vectors, it might be useful to do this if it
|
|
// has multiple extractelement uses. For vector select, that seems to
|
|
// fight the vectorizer.
|
|
|
|
// If we are extracting an element from a vector select or a select on
|
|
// vectors, a select on the scalars extracted from the vector arguments.
|
|
Value *TrueVal = SI->getTrueValue();
|
|
Value *FalseVal = SI->getFalseValue();
|
|
|
|
Value *Cond = SI->getCondition();
|
|
if (Cond->getType()->isVectorTy()) {
|
|
Cond = Builder->CreateExtractElement(Cond,
|
|
EI.getIndexOperand(),
|
|
Cond->getName() + ".elt");
|
|
}
|
|
|
|
Value *V1Elem
|
|
= Builder->CreateExtractElement(TrueVal,
|
|
EI.getIndexOperand(),
|
|
TrueVal->getName() + ".elt");
|
|
|
|
Value *V2Elem
|
|
= Builder->CreateExtractElement(FalseVal,
|
|
EI.getIndexOperand(),
|
|
FalseVal->getName() + ".elt");
|
|
return SelectInst::Create(Cond,
|
|
V1Elem,
|
|
V2Elem,
|
|
SI->getName() + ".elt");
|
|
}
|
|
}
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
/// 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(LHS->getType() == RHS->getType() &&
|
|
"Invalid CollectSingleShuffleElements");
|
|
unsigned NumElts = V->getType()->getVectorNumElements();
|
|
|
|
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.
|
|
// We can handle this if the vector we are inserting 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))) {
|
|
unsigned ExtractedIdx =
|
|
cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
|
|
unsigned NumLHSElts = LHS->getType()->getVectorNumElements();
|
|
|
|
// This must be extracting from either LHS or RHS.
|
|
if (EI->getOperand(0) == LHS || EI->getOperand(0) == RHS) {
|
|
// We can handle this if the vector we are inserting 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 + NumLHSElts);
|
|
}
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
|
|
/// We are building a shuffle to create V, which is a sequence of insertelement,
|
|
/// extractelement pairs. If PermittedRHS is set, then we must either use it or
|
|
/// not rely on the second vector source. Return a std::pair containing the
|
|
/// left and right vectors of the proposed shuffle (or 0), and set the Mask
|
|
/// parameter as required.
|
|
///
|
|
/// Note: we intentionally don't try to fold earlier shuffles since they have
|
|
/// often been chosen carefully to be efficiently implementable on the target.
|
|
typedef std::pair<Value *, Value *> ShuffleOps;
|
|
|
|
static ShuffleOps CollectShuffleElements(Value *V,
|
|
SmallVectorImpl<Constant *> &Mask,
|
|
Value *PermittedRHS) {
|
|
assert(V->getType()->isVectorTy() && "Invalid shuffle!");
|
|
unsigned NumElts = cast<VectorType>(V->getType())->getNumElements();
|
|
|
|
if (isa<UndefValue>(V)) {
|
|
Mask.assign(NumElts, UndefValue::get(Type::getInt32Ty(V->getContext())));
|
|
return std::make_pair(
|
|
PermittedRHS ? UndefValue::get(PermittedRHS->getType()) : V, nullptr);
|
|
}
|
|
|
|
if (isa<ConstantAggregateZero>(V)) {
|
|
Mask.assign(NumElts, ConstantInt::get(Type::getInt32Ty(V->getContext()),0));
|
|
return std::make_pair(V, nullptr);
|
|
}
|
|
|
|
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)) {
|
|
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) == PermittedRHS || PermittedRHS == nullptr) {
|
|
Value *RHS = EI->getOperand(0);
|
|
ShuffleOps LR = CollectShuffleElements(VecOp, Mask, RHS);
|
|
assert(LR.second == nullptr || LR.second == RHS);
|
|
|
|
if (LR.first->getType() != RHS->getType()) {
|
|
// We tried our best, but we can't find anything compatible with RHS
|
|
// further up the chain. Return a trivial shuffle.
|
|
for (unsigned i = 0; i < NumElts; ++i)
|
|
Mask[i] = ConstantInt::get(Type::getInt32Ty(V->getContext()), i);
|
|
return std::make_pair(V, nullptr);
|
|
}
|
|
|
|
unsigned NumLHSElts = RHS->getType()->getVectorNumElements();
|
|
Mask[InsertedIdx % NumElts] =
|
|
ConstantInt::get(Type::getInt32Ty(V->getContext()),
|
|
NumLHSElts+ExtractedIdx);
|
|
return std::make_pair(LR.first, RHS);
|
|
}
|
|
|
|
if (VecOp == PermittedRHS) {
|
|
// We've gone as far as we can: anything on the other side of the
|
|
// extractelement will already have been converted into a shuffle.
|
|
unsigned NumLHSElts =
|
|
EI->getOperand(0)->getType()->getVectorNumElements();
|
|
for (unsigned i = 0; i != NumElts; ++i)
|
|
Mask.push_back(ConstantInt::get(
|
|
Type::getInt32Ty(V->getContext()),
|
|
i == InsertedIdx ? ExtractedIdx : NumLHSElts + i));
|
|
return std::make_pair(EI->getOperand(0), PermittedRHS);
|
|
}
|
|
|
|
// If this insertelement is a chain that comes from exactly these two
|
|
// vectors, return the vector and the effective shuffle.
|
|
if (EI->getOperand(0)->getType() == PermittedRHS->getType() &&
|
|
CollectSingleShuffleElements(IEI, EI->getOperand(0), PermittedRHS,
|
|
Mask))
|
|
return std::make_pair(EI->getOperand(0), PermittedRHS);
|
|
}
|
|
}
|
|
}
|
|
|
|
// 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 std::make_pair(V, nullptr);
|
|
}
|
|
|
|
/// Try to find redundant insertvalue instructions, like the following ones:
|
|
/// %0 = insertvalue { i8, i32 } undef, i8 %x, 0
|
|
/// %1 = insertvalue { i8, i32 } %0, i8 %y, 0
|
|
/// Here the second instruction inserts values at the same indices, as the
|
|
/// first one, making the first one redundant.
|
|
/// It should be transformed to:
|
|
/// %0 = insertvalue { i8, i32 } undef, i8 %y, 0
|
|
Instruction *InstCombiner::visitInsertValueInst(InsertValueInst &I) {
|
|
bool IsRedundant = false;
|
|
ArrayRef<unsigned int> FirstIndices = I.getIndices();
|
|
|
|
// If there is a chain of insertvalue instructions (each of them except the
|
|
// last one has only one use and it's another insertvalue insn from this
|
|
// chain), check if any of the 'children' uses the same indices as the first
|
|
// instruction. In this case, the first one is redundant.
|
|
Value *V = &I;
|
|
unsigned Depth = 0;
|
|
while (V->hasOneUse() && Depth < 10) {
|
|
User *U = V->user_back();
|
|
auto UserInsInst = dyn_cast<InsertValueInst>(U);
|
|
if (!UserInsInst || U->getOperand(0) != V)
|
|
break;
|
|
if (UserInsInst->getIndices() == FirstIndices) {
|
|
IsRedundant = true;
|
|
break;
|
|
}
|
|
V = UserInsInst;
|
|
Depth++;
|
|
}
|
|
|
|
if (IsRedundant)
|
|
return ReplaceInstUsesWith(I, I.getOperand(0));
|
|
return nullptr;
|
|
}
|
|
|
|
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)) {
|
|
unsigned NumInsertVectorElts = IE.getType()->getNumElements();
|
|
unsigned NumExtractVectorElts =
|
|
EI->getOperand(0)->getType()->getVectorNumElements();
|
|
unsigned ExtractedIdx =
|
|
cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
|
|
unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue();
|
|
|
|
if (ExtractedIdx >= NumExtractVectorElts) // Out of range extract.
|
|
return ReplaceInstUsesWith(IE, VecOp);
|
|
|
|
if (InsertedIdx >= NumInsertVectorElts) // 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.user_back())) {
|
|
SmallVector<Constant*, 16> Mask;
|
|
ShuffleOps LR = CollectShuffleElements(&IE, Mask, nullptr);
|
|
|
|
// The proposed shuffle may be trivial, in which case we shouldn't
|
|
// perform the combine.
|
|
if (LR.first != &IE && LR.second != &IE) {
|
|
// We now have a shuffle of LHS, RHS, Mask.
|
|
if (LR.second == nullptr)
|
|
LR.second = UndefValue::get(LR.first->getType());
|
|
return new ShuffleVectorInst(LR.first, LR.second,
|
|
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 nullptr;
|
|
}
|
|
|
|
/// Return true if we can evaluate the specified expression tree if the vector
|
|
/// elements were shuffled in a different order.
|
|
static bool CanEvaluateShuffled(Value *V, ArrayRef<int> Mask,
|
|
unsigned Depth = 5) {
|
|
// We can always reorder the elements of a constant.
|
|
if (isa<Constant>(V))
|
|
return true;
|
|
|
|
// We won't reorder vector arguments. No IPO here.
|
|
Instruction *I = dyn_cast<Instruction>(V);
|
|
if (!I) return false;
|
|
|
|
// Two users may expect different orders of the elements. Don't try it.
|
|
if (!I->hasOneUse())
|
|
return false;
|
|
|
|
if (Depth == 0) return false;
|
|
|
|
switch (I->getOpcode()) {
|
|
case Instruction::Add:
|
|
case Instruction::FAdd:
|
|
case Instruction::Sub:
|
|
case Instruction::FSub:
|
|
case Instruction::Mul:
|
|
case Instruction::FMul:
|
|
case Instruction::UDiv:
|
|
case Instruction::SDiv:
|
|
case Instruction::FDiv:
|
|
case Instruction::URem:
|
|
case Instruction::SRem:
|
|
case Instruction::FRem:
|
|
case Instruction::Shl:
|
|
case Instruction::LShr:
|
|
case Instruction::AShr:
|
|
case Instruction::And:
|
|
case Instruction::Or:
|
|
case Instruction::Xor:
|
|
case Instruction::ICmp:
|
|
case Instruction::FCmp:
|
|
case Instruction::Trunc:
|
|
case Instruction::ZExt:
|
|
case Instruction::SExt:
|
|
case Instruction::FPToUI:
|
|
case Instruction::FPToSI:
|
|
case Instruction::UIToFP:
|
|
case Instruction::SIToFP:
|
|
case Instruction::FPTrunc:
|
|
case Instruction::FPExt:
|
|
case Instruction::GetElementPtr: {
|
|
for (int i = 0, e = I->getNumOperands(); i != e; ++i) {
|
|
if (!CanEvaluateShuffled(I->getOperand(i), Mask, Depth-1))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
case Instruction::InsertElement: {
|
|
ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(2));
|
|
if (!CI) return false;
|
|
int ElementNumber = CI->getLimitedValue();
|
|
|
|
// Verify that 'CI' does not occur twice in Mask. A single 'insertelement'
|
|
// can't put an element into multiple indices.
|
|
bool SeenOnce = false;
|
|
for (int i = 0, e = Mask.size(); i != e; ++i) {
|
|
if (Mask[i] == ElementNumber) {
|
|
if (SeenOnce)
|
|
return false;
|
|
SeenOnce = true;
|
|
}
|
|
}
|
|
return CanEvaluateShuffled(I->getOperand(0), Mask, Depth-1);
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/// Rebuild a new instruction just like 'I' but with the new operands given.
|
|
/// In the event of type mismatch, the type of the operands is correct.
|
|
static Value *BuildNew(Instruction *I, ArrayRef<Value*> NewOps) {
|
|
// We don't want to use the IRBuilder here because we want the replacement
|
|
// instructions to appear next to 'I', not the builder's insertion point.
|
|
switch (I->getOpcode()) {
|
|
case Instruction::Add:
|
|
case Instruction::FAdd:
|
|
case Instruction::Sub:
|
|
case Instruction::FSub:
|
|
case Instruction::Mul:
|
|
case Instruction::FMul:
|
|
case Instruction::UDiv:
|
|
case Instruction::SDiv:
|
|
case Instruction::FDiv:
|
|
case Instruction::URem:
|
|
case Instruction::SRem:
|
|
case Instruction::FRem:
|
|
case Instruction::Shl:
|
|
case Instruction::LShr:
|
|
case Instruction::AShr:
|
|
case Instruction::And:
|
|
case Instruction::Or:
|
|
case Instruction::Xor: {
|
|
BinaryOperator *BO = cast<BinaryOperator>(I);
|
|
assert(NewOps.size() == 2 && "binary operator with #ops != 2");
|
|
BinaryOperator *New =
|
|
BinaryOperator::Create(cast<BinaryOperator>(I)->getOpcode(),
|
|
NewOps[0], NewOps[1], "", BO);
|
|
if (isa<OverflowingBinaryOperator>(BO)) {
|
|
New->setHasNoUnsignedWrap(BO->hasNoUnsignedWrap());
|
|
New->setHasNoSignedWrap(BO->hasNoSignedWrap());
|
|
}
|
|
if (isa<PossiblyExactOperator>(BO)) {
|
|
New->setIsExact(BO->isExact());
|
|
}
|
|
if (isa<FPMathOperator>(BO))
|
|
New->copyFastMathFlags(I);
|
|
return New;
|
|
}
|
|
case Instruction::ICmp:
|
|
assert(NewOps.size() == 2 && "icmp with #ops != 2");
|
|
return new ICmpInst(I, cast<ICmpInst>(I)->getPredicate(),
|
|
NewOps[0], NewOps[1]);
|
|
case Instruction::FCmp:
|
|
assert(NewOps.size() == 2 && "fcmp with #ops != 2");
|
|
return new FCmpInst(I, cast<FCmpInst>(I)->getPredicate(),
|
|
NewOps[0], NewOps[1]);
|
|
case Instruction::Trunc:
|
|
case Instruction::ZExt:
|
|
case Instruction::SExt:
|
|
case Instruction::FPToUI:
|
|
case Instruction::FPToSI:
|
|
case Instruction::UIToFP:
|
|
case Instruction::SIToFP:
|
|
case Instruction::FPTrunc:
|
|
case Instruction::FPExt: {
|
|
// It's possible that the mask has a different number of elements from
|
|
// the original cast. We recompute the destination type to match the mask.
|
|
Type *DestTy =
|
|
VectorType::get(I->getType()->getScalarType(),
|
|
NewOps[0]->getType()->getVectorNumElements());
|
|
assert(NewOps.size() == 1 && "cast with #ops != 1");
|
|
return CastInst::Create(cast<CastInst>(I)->getOpcode(), NewOps[0], DestTy,
|
|
"", I);
|
|
}
|
|
case Instruction::GetElementPtr: {
|
|
Value *Ptr = NewOps[0];
|
|
ArrayRef<Value*> Idx = NewOps.slice(1);
|
|
GetElementPtrInst *GEP = GetElementPtrInst::Create(
|
|
cast<GetElementPtrInst>(I)->getSourceElementType(), Ptr, Idx, "", I);
|
|
GEP->setIsInBounds(cast<GetElementPtrInst>(I)->isInBounds());
|
|
return GEP;
|
|
}
|
|
}
|
|
llvm_unreachable("failed to rebuild vector instructions");
|
|
}
|
|
|
|
Value *
|
|
InstCombiner::EvaluateInDifferentElementOrder(Value *V, ArrayRef<int> Mask) {
|
|
// Mask.size() does not need to be equal to the number of vector elements.
|
|
|
|
assert(V->getType()->isVectorTy() && "can't reorder non-vector elements");
|
|
if (isa<UndefValue>(V)) {
|
|
return UndefValue::get(VectorType::get(V->getType()->getScalarType(),
|
|
Mask.size()));
|
|
}
|
|
if (isa<ConstantAggregateZero>(V)) {
|
|
return ConstantAggregateZero::get(
|
|
VectorType::get(V->getType()->getScalarType(),
|
|
Mask.size()));
|
|
}
|
|
if (Constant *C = dyn_cast<Constant>(V)) {
|
|
SmallVector<Constant *, 16> MaskValues;
|
|
for (int i = 0, e = Mask.size(); i != e; ++i) {
|
|
if (Mask[i] == -1)
|
|
MaskValues.push_back(UndefValue::get(Builder->getInt32Ty()));
|
|
else
|
|
MaskValues.push_back(Builder->getInt32(Mask[i]));
|
|
}
|
|
return ConstantExpr::getShuffleVector(C, UndefValue::get(C->getType()),
|
|
ConstantVector::get(MaskValues));
|
|
}
|
|
|
|
Instruction *I = cast<Instruction>(V);
|
|
switch (I->getOpcode()) {
|
|
case Instruction::Add:
|
|
case Instruction::FAdd:
|
|
case Instruction::Sub:
|
|
case Instruction::FSub:
|
|
case Instruction::Mul:
|
|
case Instruction::FMul:
|
|
case Instruction::UDiv:
|
|
case Instruction::SDiv:
|
|
case Instruction::FDiv:
|
|
case Instruction::URem:
|
|
case Instruction::SRem:
|
|
case Instruction::FRem:
|
|
case Instruction::Shl:
|
|
case Instruction::LShr:
|
|
case Instruction::AShr:
|
|
case Instruction::And:
|
|
case Instruction::Or:
|
|
case Instruction::Xor:
|
|
case Instruction::ICmp:
|
|
case Instruction::FCmp:
|
|
case Instruction::Trunc:
|
|
case Instruction::ZExt:
|
|
case Instruction::SExt:
|
|
case Instruction::FPToUI:
|
|
case Instruction::FPToSI:
|
|
case Instruction::UIToFP:
|
|
case Instruction::SIToFP:
|
|
case Instruction::FPTrunc:
|
|
case Instruction::FPExt:
|
|
case Instruction::Select:
|
|
case Instruction::GetElementPtr: {
|
|
SmallVector<Value*, 8> NewOps;
|
|
bool NeedsRebuild = (Mask.size() != I->getType()->getVectorNumElements());
|
|
for (int i = 0, e = I->getNumOperands(); i != e; ++i) {
|
|
Value *V = EvaluateInDifferentElementOrder(I->getOperand(i), Mask);
|
|
NewOps.push_back(V);
|
|
NeedsRebuild |= (V != I->getOperand(i));
|
|
}
|
|
if (NeedsRebuild) {
|
|
return BuildNew(I, NewOps);
|
|
}
|
|
return I;
|
|
}
|
|
case Instruction::InsertElement: {
|
|
int Element = cast<ConstantInt>(I->getOperand(2))->getLimitedValue();
|
|
|
|
// The insertelement was inserting at Element. Figure out which element
|
|
// that becomes after shuffling. The answer is guaranteed to be unique
|
|
// by CanEvaluateShuffled.
|
|
bool Found = false;
|
|
int Index = 0;
|
|
for (int e = Mask.size(); Index != e; ++Index) {
|
|
if (Mask[Index] == Element) {
|
|
Found = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// If element is not in Mask, no need to handle the operand 1 (element to
|
|
// be inserted). Just evaluate values in operand 0 according to Mask.
|
|
if (!Found)
|
|
return EvaluateInDifferentElementOrder(I->getOperand(0), Mask);
|
|
|
|
Value *V = EvaluateInDifferentElementOrder(I->getOperand(0), Mask);
|
|
return InsertElementInst::Create(V, I->getOperand(1),
|
|
Builder->getInt32(Index), "", I);
|
|
}
|
|
}
|
|
llvm_unreachable("failed to reorder elements of vector instruction!");
|
|
}
|
|
|
|
static void RecognizeIdentityMask(const SmallVectorImpl<int> &Mask,
|
|
bool &isLHSID, bool &isRHSID) {
|
|
isLHSID = 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);
|
|
}
|
|
}
|
|
|
|
// Returns true if the shuffle is extracting a contiguous range of values from
|
|
// LHS, for example:
|
|
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
|
// Input: |AA|BB|CC|DD|EE|FF|GG|HH|II|JJ|KK|LL|MM|NN|OO|PP|
|
|
// Shuffles to: |EE|FF|GG|HH|
|
|
// +--+--+--+--+
|
|
static bool isShuffleExtractingFromLHS(ShuffleVectorInst &SVI,
|
|
SmallVector<int, 16> &Mask) {
|
|
unsigned LHSElems =
|
|
cast<VectorType>(SVI.getOperand(0)->getType())->getNumElements();
|
|
unsigned MaskElems = Mask.size();
|
|
unsigned BegIdx = Mask.front();
|
|
unsigned EndIdx = Mask.back();
|
|
if (BegIdx > EndIdx || EndIdx >= LHSElems || EndIdx - BegIdx != MaskElems - 1)
|
|
return false;
|
|
for (unsigned I = 0; I != MaskElems; ++I)
|
|
if (static_cast<unsigned>(Mask[I]) != BegIdx + I)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
|
|
Value *LHS = SVI.getOperand(0);
|
|
Value *RHS = SVI.getOperand(1);
|
|
SmallVector<int, 16> Mask = SVI.getShuffleMask();
|
|
Type *Int32Ty = Type::getInt32Ty(SVI.getContext());
|
|
|
|
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(Int32Ty));
|
|
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(Int32Ty));
|
|
} else {
|
|
Mask[i] = Mask[i] % e; // Force to LHS.
|
|
Elts.push_back(ConstantInt::get(Int32Ty, 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, isRHSID;
|
|
RecognizeIdentityMask(Mask, isLHSID, isRHSID);
|
|
|
|
// Eliminate identity shuffles.
|
|
if (isLHSID) return ReplaceInstUsesWith(SVI, LHS);
|
|
if (isRHSID) return ReplaceInstUsesWith(SVI, RHS);
|
|
}
|
|
|
|
if (isa<UndefValue>(RHS) && CanEvaluateShuffled(LHS, Mask)) {
|
|
Value *V = EvaluateInDifferentElementOrder(LHS, Mask);
|
|
return ReplaceInstUsesWith(SVI, V);
|
|
}
|
|
|
|
// SROA generates shuffle+bitcast when the extracted sub-vector is bitcast to
|
|
// a non-vector type. We can instead bitcast the original vector followed by
|
|
// an extract of the desired element:
|
|
//
|
|
// %sroa = shufflevector <16 x i8> %in, <16 x i8> undef,
|
|
// <4 x i32> <i32 0, i32 1, i32 2, i32 3>
|
|
// %1 = bitcast <4 x i8> %sroa to i32
|
|
// Becomes:
|
|
// %bc = bitcast <16 x i8> %in to <4 x i32>
|
|
// %ext = extractelement <4 x i32> %bc, i32 0
|
|
//
|
|
// If the shuffle is extracting a contiguous range of values from the input
|
|
// vector then each use which is a bitcast of the extracted size can be
|
|
// replaced. This will work if the vector types are compatible, and the begin
|
|
// index is aligned to a value in the casted vector type. If the begin index
|
|
// isn't aligned then we can shuffle the original vector (keeping the same
|
|
// vector type) before extracting.
|
|
//
|
|
// This code will bail out if the target type is fundamentally incompatible
|
|
// with vectors of the source type.
|
|
//
|
|
// Example of <16 x i8>, target type i32:
|
|
// Index range [4,8): v-----------v Will work.
|
|
// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
|
// <16 x i8>: | | | | | | | | | | | | | | | | |
|
|
// <4 x i32>: | | | | |
|
|
// +-----------+-----------+-----------+-----------+
|
|
// Index range [6,10): ^-----------^ Needs an extra shuffle.
|
|
// Target type i40: ^--------------^ Won't work, bail.
|
|
if (isShuffleExtractingFromLHS(SVI, Mask)) {
|
|
Value *V = LHS;
|
|
unsigned MaskElems = Mask.size();
|
|
unsigned BegIdx = Mask.front();
|
|
VectorType *SrcTy = cast<VectorType>(V->getType());
|
|
unsigned VecBitWidth = SrcTy->getBitWidth();
|
|
unsigned SrcElemBitWidth = DL.getTypeSizeInBits(SrcTy->getElementType());
|
|
assert(SrcElemBitWidth && "vector elements must have a bitwidth");
|
|
unsigned SrcNumElems = SrcTy->getNumElements();
|
|
SmallVector<BitCastInst *, 8> BCs;
|
|
DenseMap<Type *, Value *> NewBCs;
|
|
for (User *U : SVI.users())
|
|
if (BitCastInst *BC = dyn_cast<BitCastInst>(U))
|
|
if (!BC->use_empty())
|
|
// Only visit bitcasts that weren't previously handled.
|
|
BCs.push_back(BC);
|
|
for (BitCastInst *BC : BCs) {
|
|
Type *TgtTy = BC->getDestTy();
|
|
unsigned TgtElemBitWidth = DL.getTypeSizeInBits(TgtTy);
|
|
if (!TgtElemBitWidth)
|
|
continue;
|
|
unsigned TgtNumElems = VecBitWidth / TgtElemBitWidth;
|
|
bool VecBitWidthsEqual = VecBitWidth == TgtNumElems * TgtElemBitWidth;
|
|
bool BegIsAligned = 0 == ((SrcElemBitWidth * BegIdx) % TgtElemBitWidth);
|
|
if (!VecBitWidthsEqual)
|
|
continue;
|
|
if (!VectorType::isValidElementType(TgtTy))
|
|
continue;
|
|
VectorType *CastSrcTy = VectorType::get(TgtTy, TgtNumElems);
|
|
if (!BegIsAligned) {
|
|
// Shuffle the input so [0,NumElements) contains the output, and
|
|
// [NumElems,SrcNumElems) is undef.
|
|
SmallVector<Constant *, 16> ShuffleMask(SrcNumElems,
|
|
UndefValue::get(Int32Ty));
|
|
for (unsigned I = 0, E = MaskElems, Idx = BegIdx; I != E; ++Idx, ++I)
|
|
ShuffleMask[I] = ConstantInt::get(Int32Ty, Idx);
|
|
V = Builder->CreateShuffleVector(V, UndefValue::get(V->getType()),
|
|
ConstantVector::get(ShuffleMask),
|
|
SVI.getName() + ".extract");
|
|
BegIdx = 0;
|
|
}
|
|
unsigned SrcElemsPerTgtElem = TgtElemBitWidth / SrcElemBitWidth;
|
|
assert(SrcElemsPerTgtElem);
|
|
BegIdx /= SrcElemsPerTgtElem;
|
|
bool BCAlreadyExists = NewBCs.find(CastSrcTy) != NewBCs.end();
|
|
auto *NewBC =
|
|
BCAlreadyExists
|
|
? NewBCs[CastSrcTy]
|
|
: Builder->CreateBitCast(V, CastSrcTy, SVI.getName() + ".bc");
|
|
if (!BCAlreadyExists)
|
|
NewBCs[CastSrcTy] = NewBC;
|
|
auto *Ext = Builder->CreateExtractElement(
|
|
NewBC, ConstantInt::get(Int32Ty, BegIdx), SVI.getName() + ".extract");
|
|
// The shufflevector isn't being replaced: the bitcast that used it
|
|
// is. InstCombine will visit the newly-created instructions.
|
|
ReplaceInstUsesWith(*BC, Ext);
|
|
MadeChange = true;
|
|
}
|
|
}
|
|
|
|
// 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 = nullptr;
|
|
if (RHSShuffle)
|
|
if (!isa<UndefValue>(RHSShuffle->getOperand(1)))
|
|
RHSShuffle = nullptr;
|
|
if (!LHSShuffle && !RHSShuffle)
|
|
return MadeChange ? &SVI : nullptr;
|
|
|
|
Value* LHSOp0 = nullptr;
|
|
Value* LHSOp1 = nullptr;
|
|
Value* RHSOp0 = nullptr;
|
|
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 = nullptr;
|
|
}
|
|
|
|
if (newLHS == LHS && newRHS == RHS)
|
|
return MadeChange ? &SVI : nullptr;
|
|
|
|
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 across the two vectors.
|
|
if (eltMask >= 0 && newRHS != nullptr && 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;
|
|
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)
|
|
newRHS = UndefValue::get(newLHS->getType());
|
|
return new ShuffleVectorInst(newLHS, newRHS, ConstantVector::get(Elts));
|
|
}
|
|
|
|
// If the result mask is an identity, replace uses of this instruction with
|
|
// corresponding argument.
|
|
bool isLHSID, isRHSID;
|
|
RecognizeIdentityMask(newMask, isLHSID, isRHSID);
|
|
if (isLHSID && VWidth == LHSOp0Width) return ReplaceInstUsesWith(SVI, newLHS);
|
|
if (isRHSID && VWidth == RHSOp0Width) return ReplaceInstUsesWith(SVI, newRHS);
|
|
|
|
return MadeChange ? &SVI : nullptr;
|
|
}
|