0bf1591d01
foldPermuteOfBinops currently requires both binop operands to be oneuse shuffles to fold the shuffles across the binop, but there will be cases where its still profitable to fold across the binop with only one foldable shuffle.
3287 lines
127 KiB
C++
3287 lines
127 KiB
C++
//===------- VectorCombine.cpp - Optimize partial vector operations -------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This pass optimizes scalar/vector interactions using target cost models. The
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// transforms implemented here may not fit in traditional loop-based or SLP
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// vectorization passes.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Vectorize/VectorCombine.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/ScopeExit.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/Analysis/AssumptionCache.h"
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#include "llvm/Analysis/BasicAliasAnalysis.h"
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#include "llvm/Analysis/GlobalsModRef.h"
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#include "llvm/Analysis/Loads.h"
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#include "llvm/Analysis/TargetTransformInfo.h"
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#include "llvm/Analysis/ValueTracking.h"
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#include "llvm/Analysis/VectorUtils.h"
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#include "llvm/IR/Dominators.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/PatternMatch.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Transforms/Utils/Local.h"
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#include "llvm/Transforms/Utils/LoopUtils.h"
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#include <numeric>
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#include <queue>
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#define DEBUG_TYPE "vector-combine"
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#include "llvm/Transforms/Utils/InstructionWorklist.h"
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using namespace llvm;
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using namespace llvm::PatternMatch;
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STATISTIC(NumVecLoad, "Number of vector loads formed");
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STATISTIC(NumVecCmp, "Number of vector compares formed");
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STATISTIC(NumVecBO, "Number of vector binops formed");
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STATISTIC(NumVecCmpBO, "Number of vector compare + binop formed");
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STATISTIC(NumShufOfBitcast, "Number of shuffles moved after bitcast");
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STATISTIC(NumScalarBO, "Number of scalar binops formed");
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STATISTIC(NumScalarCmp, "Number of scalar compares formed");
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static cl::opt<bool> DisableVectorCombine(
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"disable-vector-combine", cl::init(false), cl::Hidden,
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cl::desc("Disable all vector combine transforms"));
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static cl::opt<bool> DisableBinopExtractShuffle(
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"disable-binop-extract-shuffle", cl::init(false), cl::Hidden,
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cl::desc("Disable binop extract to shuffle transforms"));
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static cl::opt<unsigned> MaxInstrsToScan(
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"vector-combine-max-scan-instrs", cl::init(30), cl::Hidden,
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cl::desc("Max number of instructions to scan for vector combining."));
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static const unsigned InvalidIndex = std::numeric_limits<unsigned>::max();
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namespace {
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class VectorCombine {
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public:
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VectorCombine(Function &F, const TargetTransformInfo &TTI,
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const DominatorTree &DT, AAResults &AA, AssumptionCache &AC,
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const DataLayout *DL, TTI::TargetCostKind CostKind,
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bool TryEarlyFoldsOnly)
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: F(F), Builder(F.getContext()), TTI(TTI), DT(DT), AA(AA), AC(AC), DL(DL),
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CostKind(CostKind), TryEarlyFoldsOnly(TryEarlyFoldsOnly) {}
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bool run();
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private:
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Function &F;
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IRBuilder<> Builder;
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const TargetTransformInfo &TTI;
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const DominatorTree &DT;
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AAResults &AA;
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AssumptionCache &AC;
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const DataLayout *DL;
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TTI::TargetCostKind CostKind;
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/// If true, only perform beneficial early IR transforms. Do not introduce new
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/// vector operations.
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bool TryEarlyFoldsOnly;
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InstructionWorklist Worklist;
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// TODO: Direct calls from the top-level "run" loop use a plain "Instruction"
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// parameter. That should be updated to specific sub-classes because the
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// run loop was changed to dispatch on opcode.
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bool vectorizeLoadInsert(Instruction &I);
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bool widenSubvectorLoad(Instruction &I);
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ExtractElementInst *getShuffleExtract(ExtractElementInst *Ext0,
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ExtractElementInst *Ext1,
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unsigned PreferredExtractIndex) const;
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bool isExtractExtractCheap(ExtractElementInst *Ext0, ExtractElementInst *Ext1,
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const Instruction &I,
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ExtractElementInst *&ConvertToShuffle,
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unsigned PreferredExtractIndex);
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void foldExtExtCmp(ExtractElementInst *Ext0, ExtractElementInst *Ext1,
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Instruction &I);
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void foldExtExtBinop(ExtractElementInst *Ext0, ExtractElementInst *Ext1,
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Instruction &I);
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bool foldExtractExtract(Instruction &I);
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bool foldInsExtFNeg(Instruction &I);
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bool foldInsExtVectorToShuffle(Instruction &I);
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bool foldBitcastShuffle(Instruction &I);
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bool scalarizeBinopOrCmp(Instruction &I);
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bool scalarizeVPIntrinsic(Instruction &I);
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bool foldExtractedCmps(Instruction &I);
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bool foldSingleElementStore(Instruction &I);
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bool scalarizeLoadExtract(Instruction &I);
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bool foldConcatOfBoolMasks(Instruction &I);
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bool foldPermuteOfBinops(Instruction &I);
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bool foldShuffleOfBinops(Instruction &I);
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bool foldShuffleOfCastops(Instruction &I);
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bool foldShuffleOfShuffles(Instruction &I);
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bool foldShuffleOfIntrinsics(Instruction &I);
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bool foldShuffleToIdentity(Instruction &I);
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bool foldShuffleFromReductions(Instruction &I);
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bool foldCastFromReductions(Instruction &I);
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bool foldSelectShuffle(Instruction &I, bool FromReduction = false);
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bool shrinkType(Instruction &I);
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void replaceValue(Value &Old, Value &New) {
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LLVM_DEBUG(dbgs() << "VC: Replacing: " << Old << '\n');
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LLVM_DEBUG(dbgs() << " With: " << New << '\n');
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Old.replaceAllUsesWith(&New);
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if (auto *NewI = dyn_cast<Instruction>(&New)) {
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New.takeName(&Old);
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Worklist.pushUsersToWorkList(*NewI);
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Worklist.pushValue(NewI);
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}
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Worklist.pushValue(&Old);
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}
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void eraseInstruction(Instruction &I) {
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LLVM_DEBUG(dbgs() << "VC: Erasing: " << I << '\n');
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SmallVector<Value *> Ops(I.operands());
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Worklist.remove(&I);
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I.eraseFromParent();
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// Push remaining users of the operands and then the operand itself - allows
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// further folds that were hindered by OneUse limits.
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for (Value *Op : Ops)
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if (auto *OpI = dyn_cast<Instruction>(Op)) {
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Worklist.pushUsersToWorkList(*OpI);
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Worklist.pushValue(OpI);
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}
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}
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};
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} // namespace
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/// Return the source operand of a potentially bitcasted value. If there is no
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/// bitcast, return the input value itself.
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static Value *peekThroughBitcasts(Value *V) {
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while (auto *BitCast = dyn_cast<BitCastInst>(V))
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V = BitCast->getOperand(0);
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return V;
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}
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static bool canWidenLoad(LoadInst *Load, const TargetTransformInfo &TTI) {
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// Do not widen load if atomic/volatile or under asan/hwasan/memtag/tsan.
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// The widened load may load data from dirty regions or create data races
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// non-existent in the source.
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if (!Load || !Load->isSimple() || !Load->hasOneUse() ||
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Load->getFunction()->hasFnAttribute(Attribute::SanitizeMemTag) ||
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mustSuppressSpeculation(*Load))
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return false;
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// We are potentially transforming byte-sized (8-bit) memory accesses, so make
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// sure we have all of our type-based constraints in place for this target.
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Type *ScalarTy = Load->getType()->getScalarType();
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uint64_t ScalarSize = ScalarTy->getPrimitiveSizeInBits();
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unsigned MinVectorSize = TTI.getMinVectorRegisterBitWidth();
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if (!ScalarSize || !MinVectorSize || MinVectorSize % ScalarSize != 0 ||
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ScalarSize % 8 != 0)
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return false;
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return true;
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}
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bool VectorCombine::vectorizeLoadInsert(Instruction &I) {
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// Match insert into fixed vector of scalar value.
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// TODO: Handle non-zero insert index.
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Value *Scalar;
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if (!match(&I,
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m_InsertElt(m_Poison(), m_OneUse(m_Value(Scalar)), m_ZeroInt())))
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return false;
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// Optionally match an extract from another vector.
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Value *X;
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bool HasExtract = match(Scalar, m_ExtractElt(m_Value(X), m_ZeroInt()));
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if (!HasExtract)
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X = Scalar;
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auto *Load = dyn_cast<LoadInst>(X);
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if (!canWidenLoad(Load, TTI))
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return false;
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Type *ScalarTy = Scalar->getType();
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uint64_t ScalarSize = ScalarTy->getPrimitiveSizeInBits();
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unsigned MinVectorSize = TTI.getMinVectorRegisterBitWidth();
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// Check safety of replacing the scalar load with a larger vector load.
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// We use minimal alignment (maximum flexibility) because we only care about
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// the dereferenceable region. When calculating cost and creating a new op,
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// we may use a larger value based on alignment attributes.
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Value *SrcPtr = Load->getPointerOperand()->stripPointerCasts();
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assert(isa<PointerType>(SrcPtr->getType()) && "Expected a pointer type");
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unsigned MinVecNumElts = MinVectorSize / ScalarSize;
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auto *MinVecTy = VectorType::get(ScalarTy, MinVecNumElts, false);
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unsigned OffsetEltIndex = 0;
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Align Alignment = Load->getAlign();
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if (!isSafeToLoadUnconditionally(SrcPtr, MinVecTy, Align(1), *DL, Load, &AC,
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&DT)) {
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// It is not safe to load directly from the pointer, but we can still peek
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// through gep offsets and check if it safe to load from a base address with
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// updated alignment. If it is, we can shuffle the element(s) into place
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// after loading.
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unsigned OffsetBitWidth = DL->getIndexTypeSizeInBits(SrcPtr->getType());
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APInt Offset(OffsetBitWidth, 0);
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SrcPtr = SrcPtr->stripAndAccumulateInBoundsConstantOffsets(*DL, Offset);
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// We want to shuffle the result down from a high element of a vector, so
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// the offset must be positive.
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if (Offset.isNegative())
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return false;
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// The offset must be a multiple of the scalar element to shuffle cleanly
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// in the element's size.
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uint64_t ScalarSizeInBytes = ScalarSize / 8;
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if (Offset.urem(ScalarSizeInBytes) != 0)
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return false;
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// If we load MinVecNumElts, will our target element still be loaded?
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OffsetEltIndex = Offset.udiv(ScalarSizeInBytes).getZExtValue();
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if (OffsetEltIndex >= MinVecNumElts)
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return false;
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if (!isSafeToLoadUnconditionally(SrcPtr, MinVecTy, Align(1), *DL, Load, &AC,
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&DT))
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return false;
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// Update alignment with offset value. Note that the offset could be negated
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// to more accurately represent "(new) SrcPtr - Offset = (old) SrcPtr", but
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// negation does not change the result of the alignment calculation.
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Alignment = commonAlignment(Alignment, Offset.getZExtValue());
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}
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// Original pattern: insertelt undef, load [free casts of] PtrOp, 0
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// Use the greater of the alignment on the load or its source pointer.
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Alignment = std::max(SrcPtr->getPointerAlignment(*DL), Alignment);
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Type *LoadTy = Load->getType();
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unsigned AS = Load->getPointerAddressSpace();
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InstructionCost OldCost =
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TTI.getMemoryOpCost(Instruction::Load, LoadTy, Alignment, AS, CostKind);
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APInt DemandedElts = APInt::getOneBitSet(MinVecNumElts, 0);
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OldCost +=
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TTI.getScalarizationOverhead(MinVecTy, DemandedElts,
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/* Insert */ true, HasExtract, CostKind);
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// New pattern: load VecPtr
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InstructionCost NewCost =
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TTI.getMemoryOpCost(Instruction::Load, MinVecTy, Alignment, AS, CostKind);
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// Optionally, we are shuffling the loaded vector element(s) into place.
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// For the mask set everything but element 0 to undef to prevent poison from
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// propagating from the extra loaded memory. This will also optionally
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// shrink/grow the vector from the loaded size to the output size.
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// We assume this operation has no cost in codegen if there was no offset.
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// Note that we could use freeze to avoid poison problems, but then we might
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// still need a shuffle to change the vector size.
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auto *Ty = cast<FixedVectorType>(I.getType());
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unsigned OutputNumElts = Ty->getNumElements();
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SmallVector<int, 16> Mask(OutputNumElts, PoisonMaskElem);
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assert(OffsetEltIndex < MinVecNumElts && "Address offset too big");
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Mask[0] = OffsetEltIndex;
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if (OffsetEltIndex)
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NewCost +=
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TTI.getShuffleCost(TTI::SK_PermuteSingleSrc, MinVecTy, Mask, CostKind);
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// We can aggressively convert to the vector form because the backend can
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// invert this transform if it does not result in a performance win.
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if (OldCost < NewCost || !NewCost.isValid())
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return false;
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// It is safe and potentially profitable to load a vector directly:
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// inselt undef, load Scalar, 0 --> load VecPtr
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IRBuilder<> Builder(Load);
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Value *CastedPtr =
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Builder.CreatePointerBitCastOrAddrSpaceCast(SrcPtr, Builder.getPtrTy(AS));
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Value *VecLd = Builder.CreateAlignedLoad(MinVecTy, CastedPtr, Alignment);
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VecLd = Builder.CreateShuffleVector(VecLd, Mask);
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replaceValue(I, *VecLd);
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++NumVecLoad;
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return true;
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}
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/// If we are loading a vector and then inserting it into a larger vector with
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/// undefined elements, try to load the larger vector and eliminate the insert.
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/// This removes a shuffle in IR and may allow combining of other loaded values.
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bool VectorCombine::widenSubvectorLoad(Instruction &I) {
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// Match subvector insert of fixed vector.
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auto *Shuf = cast<ShuffleVectorInst>(&I);
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if (!Shuf->isIdentityWithPadding())
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return false;
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// Allow a non-canonical shuffle mask that is choosing elements from op1.
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unsigned NumOpElts =
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cast<FixedVectorType>(Shuf->getOperand(0)->getType())->getNumElements();
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unsigned OpIndex = any_of(Shuf->getShuffleMask(), [&NumOpElts](int M) {
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return M >= (int)(NumOpElts);
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});
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auto *Load = dyn_cast<LoadInst>(Shuf->getOperand(OpIndex));
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if (!canWidenLoad(Load, TTI))
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return false;
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// We use minimal alignment (maximum flexibility) because we only care about
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// the dereferenceable region. When calculating cost and creating a new op,
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// we may use a larger value based on alignment attributes.
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auto *Ty = cast<FixedVectorType>(I.getType());
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Value *SrcPtr = Load->getPointerOperand()->stripPointerCasts();
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assert(isa<PointerType>(SrcPtr->getType()) && "Expected a pointer type");
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Align Alignment = Load->getAlign();
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if (!isSafeToLoadUnconditionally(SrcPtr, Ty, Align(1), *DL, Load, &AC, &DT))
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return false;
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Alignment = std::max(SrcPtr->getPointerAlignment(*DL), Alignment);
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Type *LoadTy = Load->getType();
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unsigned AS = Load->getPointerAddressSpace();
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// Original pattern: insert_subvector (load PtrOp)
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// This conservatively assumes that the cost of a subvector insert into an
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// undef value is 0. We could add that cost if the cost model accurately
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// reflects the real cost of that operation.
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InstructionCost OldCost =
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TTI.getMemoryOpCost(Instruction::Load, LoadTy, Alignment, AS, CostKind);
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// New pattern: load PtrOp
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InstructionCost NewCost =
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TTI.getMemoryOpCost(Instruction::Load, Ty, Alignment, AS, CostKind);
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// We can aggressively convert to the vector form because the backend can
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// invert this transform if it does not result in a performance win.
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if (OldCost < NewCost || !NewCost.isValid())
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return false;
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IRBuilder<> Builder(Load);
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Value *CastedPtr =
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Builder.CreatePointerBitCastOrAddrSpaceCast(SrcPtr, Builder.getPtrTy(AS));
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Value *VecLd = Builder.CreateAlignedLoad(Ty, CastedPtr, Alignment);
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replaceValue(I, *VecLd);
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++NumVecLoad;
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return true;
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}
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/// Determine which, if any, of the inputs should be replaced by a shuffle
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/// followed by extract from a different index.
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ExtractElementInst *VectorCombine::getShuffleExtract(
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ExtractElementInst *Ext0, ExtractElementInst *Ext1,
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unsigned PreferredExtractIndex = InvalidIndex) const {
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auto *Index0C = dyn_cast<ConstantInt>(Ext0->getIndexOperand());
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auto *Index1C = dyn_cast<ConstantInt>(Ext1->getIndexOperand());
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assert(Index0C && Index1C && "Expected constant extract indexes");
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unsigned Index0 = Index0C->getZExtValue();
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unsigned Index1 = Index1C->getZExtValue();
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// If the extract indexes are identical, no shuffle is needed.
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if (Index0 == Index1)
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return nullptr;
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Type *VecTy = Ext0->getVectorOperand()->getType();
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assert(VecTy == Ext1->getVectorOperand()->getType() && "Need matching types");
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InstructionCost Cost0 =
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TTI.getVectorInstrCost(*Ext0, VecTy, CostKind, Index0);
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InstructionCost Cost1 =
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TTI.getVectorInstrCost(*Ext1, VecTy, CostKind, Index1);
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// If both costs are invalid no shuffle is needed
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if (!Cost0.isValid() && !Cost1.isValid())
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return nullptr;
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// We are extracting from 2 different indexes, so one operand must be shuffled
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// before performing a vector operation and/or extract. The more expensive
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// extract will be replaced by a shuffle.
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if (Cost0 > Cost1)
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return Ext0;
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if (Cost1 > Cost0)
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return Ext1;
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// If the costs are equal and there is a preferred extract index, shuffle the
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// opposite operand.
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if (PreferredExtractIndex == Index0)
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return Ext1;
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if (PreferredExtractIndex == Index1)
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return Ext0;
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// Otherwise, replace the extract with the higher index.
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return Index0 > Index1 ? Ext0 : Ext1;
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}
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/// Compare the relative costs of 2 extracts followed by scalar operation vs.
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/// vector operation(s) followed by extract. Return true if the existing
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/// instructions are cheaper than a vector alternative. Otherwise, return false
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/// and if one of the extracts should be transformed to a shufflevector, set
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/// \p ConvertToShuffle to that extract instruction.
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bool VectorCombine::isExtractExtractCheap(ExtractElementInst *Ext0,
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ExtractElementInst *Ext1,
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const Instruction &I,
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ExtractElementInst *&ConvertToShuffle,
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unsigned PreferredExtractIndex) {
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auto *Ext0IndexC = dyn_cast<ConstantInt>(Ext0->getIndexOperand());
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auto *Ext1IndexC = dyn_cast<ConstantInt>(Ext1->getIndexOperand());
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assert(Ext0IndexC && Ext1IndexC && "Expected constant extract indexes");
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unsigned Opcode = I.getOpcode();
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Value *Ext0Src = Ext0->getVectorOperand();
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Value *Ext1Src = Ext1->getVectorOperand();
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Type *ScalarTy = Ext0->getType();
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auto *VecTy = cast<VectorType>(Ext0Src->getType());
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InstructionCost ScalarOpCost, VectorOpCost;
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// Get cost estimates for scalar and vector versions of the operation.
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bool IsBinOp = Instruction::isBinaryOp(Opcode);
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if (IsBinOp) {
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ScalarOpCost = TTI.getArithmeticInstrCost(Opcode, ScalarTy, CostKind);
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VectorOpCost = TTI.getArithmeticInstrCost(Opcode, VecTy, CostKind);
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} else {
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assert((Opcode == Instruction::ICmp || Opcode == Instruction::FCmp) &&
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"Expected a compare");
|
|
CmpInst::Predicate Pred = cast<CmpInst>(I).getPredicate();
|
|
ScalarOpCost = TTI.getCmpSelInstrCost(
|
|
Opcode, ScalarTy, CmpInst::makeCmpResultType(ScalarTy), Pred, CostKind);
|
|
VectorOpCost = TTI.getCmpSelInstrCost(
|
|
Opcode, VecTy, CmpInst::makeCmpResultType(VecTy), Pred, CostKind);
|
|
}
|
|
|
|
// Get cost estimates for the extract elements. These costs will factor into
|
|
// both sequences.
|
|
unsigned Ext0Index = Ext0IndexC->getZExtValue();
|
|
unsigned Ext1Index = Ext1IndexC->getZExtValue();
|
|
|
|
InstructionCost Extract0Cost =
|
|
TTI.getVectorInstrCost(*Ext0, VecTy, CostKind, Ext0Index);
|
|
InstructionCost Extract1Cost =
|
|
TTI.getVectorInstrCost(*Ext1, VecTy, CostKind, Ext1Index);
|
|
|
|
// A more expensive extract will always be replaced by a splat shuffle.
|
|
// For example, if Ext0 is more expensive:
|
|
// opcode (extelt V0, Ext0), (ext V1, Ext1) -->
|
|
// extelt (opcode (splat V0, Ext0), V1), Ext1
|
|
// TODO: Evaluate whether that always results in lowest cost. Alternatively,
|
|
// check the cost of creating a broadcast shuffle and shuffling both
|
|
// operands to element 0.
|
|
unsigned BestExtIndex = Extract0Cost > Extract1Cost ? Ext0Index : Ext1Index;
|
|
unsigned BestInsIndex = Extract0Cost > Extract1Cost ? Ext1Index : Ext0Index;
|
|
InstructionCost CheapExtractCost = std::min(Extract0Cost, Extract1Cost);
|
|
|
|
// Extra uses of the extracts mean that we include those costs in the
|
|
// vector total because those instructions will not be eliminated.
|
|
InstructionCost OldCost, NewCost;
|
|
if (Ext0Src == Ext1Src && Ext0Index == Ext1Index) {
|
|
// Handle a special case. If the 2 extracts are identical, adjust the
|
|
// formulas to account for that. The extra use charge allows for either the
|
|
// CSE'd pattern or an unoptimized form with identical values:
|
|
// opcode (extelt V, C), (extelt V, C) --> extelt (opcode V, V), C
|
|
bool HasUseTax = Ext0 == Ext1 ? !Ext0->hasNUses(2)
|
|
: !Ext0->hasOneUse() || !Ext1->hasOneUse();
|
|
OldCost = CheapExtractCost + ScalarOpCost;
|
|
NewCost = VectorOpCost + CheapExtractCost + HasUseTax * CheapExtractCost;
|
|
} else {
|
|
// Handle the general case. Each extract is actually a different value:
|
|
// opcode (extelt V0, C0), (extelt V1, C1) --> extelt (opcode V0, V1), C
|
|
OldCost = Extract0Cost + Extract1Cost + ScalarOpCost;
|
|
NewCost = VectorOpCost + CheapExtractCost +
|
|
!Ext0->hasOneUse() * Extract0Cost +
|
|
!Ext1->hasOneUse() * Extract1Cost;
|
|
}
|
|
|
|
ConvertToShuffle = getShuffleExtract(Ext0, Ext1, PreferredExtractIndex);
|
|
if (ConvertToShuffle) {
|
|
if (IsBinOp && DisableBinopExtractShuffle)
|
|
return true;
|
|
|
|
// If we are extracting from 2 different indexes, then one operand must be
|
|
// shuffled before performing the vector operation. The shuffle mask is
|
|
// poison except for 1 lane that is being translated to the remaining
|
|
// extraction lane. Therefore, it is a splat shuffle. Ex:
|
|
// ShufMask = { poison, poison, 0, poison }
|
|
// TODO: The cost model has an option for a "broadcast" shuffle
|
|
// (splat-from-element-0), but no option for a more general splat.
|
|
if (auto *FixedVecTy = dyn_cast<FixedVectorType>(VecTy)) {
|
|
SmallVector<int> ShuffleMask(FixedVecTy->getNumElements(),
|
|
PoisonMaskElem);
|
|
ShuffleMask[BestInsIndex] = BestExtIndex;
|
|
NewCost += TTI.getShuffleCost(TargetTransformInfo::SK_PermuteSingleSrc,
|
|
VecTy, ShuffleMask, CostKind, 0, nullptr,
|
|
{ConvertToShuffle});
|
|
} else {
|
|
NewCost +=
|
|
TTI.getShuffleCost(TargetTransformInfo::SK_PermuteSingleSrc, VecTy,
|
|
{}, CostKind, 0, nullptr, {ConvertToShuffle});
|
|
}
|
|
}
|
|
|
|
// Aggressively form a vector op if the cost is equal because the transform
|
|
// may enable further optimization.
|
|
// Codegen can reverse this transform (scalarize) if it was not profitable.
|
|
return OldCost < NewCost;
|
|
}
|
|
|
|
/// Create a shuffle that translates (shifts) 1 element from the input vector
|
|
/// to a new element location.
|
|
static Value *createShiftShuffle(Value *Vec, unsigned OldIndex,
|
|
unsigned NewIndex, IRBuilder<> &Builder) {
|
|
// The shuffle mask is poison except for 1 lane that is being translated
|
|
// to the new element index. Example for OldIndex == 2 and NewIndex == 0:
|
|
// ShufMask = { 2, poison, poison, poison }
|
|
auto *VecTy = cast<FixedVectorType>(Vec->getType());
|
|
SmallVector<int, 32> ShufMask(VecTy->getNumElements(), PoisonMaskElem);
|
|
ShufMask[NewIndex] = OldIndex;
|
|
return Builder.CreateShuffleVector(Vec, ShufMask, "shift");
|
|
}
|
|
|
|
/// Given an extract element instruction with constant index operand, shuffle
|
|
/// the source vector (shift the scalar element) to a NewIndex for extraction.
|
|
/// Return null if the input can be constant folded, so that we are not creating
|
|
/// unnecessary instructions.
|
|
static ExtractElementInst *translateExtract(ExtractElementInst *ExtElt,
|
|
unsigned NewIndex,
|
|
IRBuilder<> &Builder) {
|
|
// Shufflevectors can only be created for fixed-width vectors.
|
|
Value *X = ExtElt->getVectorOperand();
|
|
if (!isa<FixedVectorType>(X->getType()))
|
|
return nullptr;
|
|
|
|
// If the extract can be constant-folded, this code is unsimplified. Defer
|
|
// to other passes to handle that.
|
|
Value *C = ExtElt->getIndexOperand();
|
|
assert(isa<ConstantInt>(C) && "Expected a constant index operand");
|
|
if (isa<Constant>(X))
|
|
return nullptr;
|
|
|
|
Value *Shuf = createShiftShuffle(X, cast<ConstantInt>(C)->getZExtValue(),
|
|
NewIndex, Builder);
|
|
return cast<ExtractElementInst>(Builder.CreateExtractElement(Shuf, NewIndex));
|
|
}
|
|
|
|
/// Try to reduce extract element costs by converting scalar compares to vector
|
|
/// compares followed by extract.
|
|
/// cmp (ext0 V0, C), (ext1 V1, C)
|
|
void VectorCombine::foldExtExtCmp(ExtractElementInst *Ext0,
|
|
ExtractElementInst *Ext1, Instruction &I) {
|
|
assert(isa<CmpInst>(&I) && "Expected a compare");
|
|
assert(cast<ConstantInt>(Ext0->getIndexOperand())->getZExtValue() ==
|
|
cast<ConstantInt>(Ext1->getIndexOperand())->getZExtValue() &&
|
|
"Expected matching constant extract indexes");
|
|
|
|
// cmp Pred (extelt V0, C), (extelt V1, C) --> extelt (cmp Pred V0, V1), C
|
|
++NumVecCmp;
|
|
CmpInst::Predicate Pred = cast<CmpInst>(&I)->getPredicate();
|
|
Value *V0 = Ext0->getVectorOperand(), *V1 = Ext1->getVectorOperand();
|
|
Value *VecCmp = Builder.CreateCmp(Pred, V0, V1);
|
|
Value *NewExt = Builder.CreateExtractElement(VecCmp, Ext0->getIndexOperand());
|
|
replaceValue(I, *NewExt);
|
|
}
|
|
|
|
/// Try to reduce extract element costs by converting scalar binops to vector
|
|
/// binops followed by extract.
|
|
/// bo (ext0 V0, C), (ext1 V1, C)
|
|
void VectorCombine::foldExtExtBinop(ExtractElementInst *Ext0,
|
|
ExtractElementInst *Ext1, Instruction &I) {
|
|
assert(isa<BinaryOperator>(&I) && "Expected a binary operator");
|
|
assert(cast<ConstantInt>(Ext0->getIndexOperand())->getZExtValue() ==
|
|
cast<ConstantInt>(Ext1->getIndexOperand())->getZExtValue() &&
|
|
"Expected matching constant extract indexes");
|
|
|
|
// bo (extelt V0, C), (extelt V1, C) --> extelt (bo V0, V1), C
|
|
++NumVecBO;
|
|
Value *V0 = Ext0->getVectorOperand(), *V1 = Ext1->getVectorOperand();
|
|
Value *VecBO =
|
|
Builder.CreateBinOp(cast<BinaryOperator>(&I)->getOpcode(), V0, V1);
|
|
|
|
// All IR flags are safe to back-propagate because any potential poison
|
|
// created in unused vector elements is discarded by the extract.
|
|
if (auto *VecBOInst = dyn_cast<Instruction>(VecBO))
|
|
VecBOInst->copyIRFlags(&I);
|
|
|
|
Value *NewExt = Builder.CreateExtractElement(VecBO, Ext0->getIndexOperand());
|
|
replaceValue(I, *NewExt);
|
|
}
|
|
|
|
/// Match an instruction with extracted vector operands.
|
|
bool VectorCombine::foldExtractExtract(Instruction &I) {
|
|
// It is not safe to transform things like div, urem, etc. because we may
|
|
// create undefined behavior when executing those on unknown vector elements.
|
|
if (!isSafeToSpeculativelyExecute(&I))
|
|
return false;
|
|
|
|
Instruction *I0, *I1;
|
|
CmpPredicate Pred = CmpInst::BAD_ICMP_PREDICATE;
|
|
if (!match(&I, m_Cmp(Pred, m_Instruction(I0), m_Instruction(I1))) &&
|
|
!match(&I, m_BinOp(m_Instruction(I0), m_Instruction(I1))))
|
|
return false;
|
|
|
|
Value *V0, *V1;
|
|
uint64_t C0, C1;
|
|
if (!match(I0, m_ExtractElt(m_Value(V0), m_ConstantInt(C0))) ||
|
|
!match(I1, m_ExtractElt(m_Value(V1), m_ConstantInt(C1))) ||
|
|
V0->getType() != V1->getType())
|
|
return false;
|
|
|
|
// If the scalar value 'I' is going to be re-inserted into a vector, then try
|
|
// to create an extract to that same element. The extract/insert can be
|
|
// reduced to a "select shuffle".
|
|
// TODO: If we add a larger pattern match that starts from an insert, this
|
|
// probably becomes unnecessary.
|
|
auto *Ext0 = cast<ExtractElementInst>(I0);
|
|
auto *Ext1 = cast<ExtractElementInst>(I1);
|
|
uint64_t InsertIndex = InvalidIndex;
|
|
if (I.hasOneUse())
|
|
match(I.user_back(),
|
|
m_InsertElt(m_Value(), m_Value(), m_ConstantInt(InsertIndex)));
|
|
|
|
ExtractElementInst *ExtractToChange;
|
|
if (isExtractExtractCheap(Ext0, Ext1, I, ExtractToChange, InsertIndex))
|
|
return false;
|
|
|
|
if (ExtractToChange) {
|
|
unsigned CheapExtractIdx = ExtractToChange == Ext0 ? C1 : C0;
|
|
ExtractElementInst *NewExtract =
|
|
translateExtract(ExtractToChange, CheapExtractIdx, Builder);
|
|
if (!NewExtract)
|
|
return false;
|
|
if (ExtractToChange == Ext0)
|
|
Ext0 = NewExtract;
|
|
else
|
|
Ext1 = NewExtract;
|
|
}
|
|
|
|
if (Pred != CmpInst::BAD_ICMP_PREDICATE)
|
|
foldExtExtCmp(Ext0, Ext1, I);
|
|
else
|
|
foldExtExtBinop(Ext0, Ext1, I);
|
|
|
|
Worklist.push(Ext0);
|
|
Worklist.push(Ext1);
|
|
return true;
|
|
}
|
|
|
|
/// Try to replace an extract + scalar fneg + insert with a vector fneg +
|
|
/// shuffle.
|
|
bool VectorCombine::foldInsExtFNeg(Instruction &I) {
|
|
// Match an insert (op (extract)) pattern.
|
|
Value *DestVec;
|
|
uint64_t Index;
|
|
Instruction *FNeg;
|
|
if (!match(&I, m_InsertElt(m_Value(DestVec), m_OneUse(m_Instruction(FNeg)),
|
|
m_ConstantInt(Index))))
|
|
return false;
|
|
|
|
// Note: This handles the canonical fneg instruction and "fsub -0.0, X".
|
|
Value *SrcVec;
|
|
Instruction *Extract;
|
|
if (!match(FNeg, m_FNeg(m_CombineAnd(
|
|
m_Instruction(Extract),
|
|
m_ExtractElt(m_Value(SrcVec), m_SpecificInt(Index))))))
|
|
return false;
|
|
|
|
auto *VecTy = cast<FixedVectorType>(I.getType());
|
|
auto *ScalarTy = VecTy->getScalarType();
|
|
auto *SrcVecTy = dyn_cast<FixedVectorType>(SrcVec->getType());
|
|
if (!SrcVecTy || ScalarTy != SrcVecTy->getScalarType())
|
|
return false;
|
|
|
|
// Ignore bogus insert/extract index.
|
|
unsigned NumElts = VecTy->getNumElements();
|
|
if (Index >= NumElts)
|
|
return false;
|
|
|
|
// We are inserting the negated element into the same lane that we extracted
|
|
// from. This is equivalent to a select-shuffle that chooses all but the
|
|
// negated element from the destination vector.
|
|
SmallVector<int> Mask(NumElts);
|
|
std::iota(Mask.begin(), Mask.end(), 0);
|
|
Mask[Index] = Index + NumElts;
|
|
InstructionCost OldCost =
|
|
TTI.getArithmeticInstrCost(Instruction::FNeg, ScalarTy, CostKind) +
|
|
TTI.getVectorInstrCost(I, VecTy, CostKind, Index);
|
|
|
|
// If the extract has one use, it will be eliminated, so count it in the
|
|
// original cost. If it has more than one use, ignore the cost because it will
|
|
// be the same before/after.
|
|
if (Extract->hasOneUse())
|
|
OldCost += TTI.getVectorInstrCost(*Extract, VecTy, CostKind, Index);
|
|
|
|
InstructionCost NewCost =
|
|
TTI.getArithmeticInstrCost(Instruction::FNeg, VecTy, CostKind) +
|
|
TTI.getShuffleCost(TargetTransformInfo::SK_PermuteTwoSrc, VecTy, Mask,
|
|
CostKind);
|
|
|
|
bool NeedLenChg = SrcVecTy->getNumElements() != NumElts;
|
|
// If the lengths of the two vectors are not equal,
|
|
// we need to add a length-change vector. Add this cost.
|
|
SmallVector<int> SrcMask;
|
|
if (NeedLenChg) {
|
|
SrcMask.assign(NumElts, PoisonMaskElem);
|
|
SrcMask[Index] = Index;
|
|
NewCost += TTI.getShuffleCost(TargetTransformInfo::SK_PermuteSingleSrc,
|
|
SrcVecTy, SrcMask, CostKind);
|
|
}
|
|
|
|
if (NewCost > OldCost)
|
|
return false;
|
|
|
|
Value *NewShuf;
|
|
// insertelt DestVec, (fneg (extractelt SrcVec, Index)), Index
|
|
Value *VecFNeg = Builder.CreateFNegFMF(SrcVec, FNeg);
|
|
if (NeedLenChg) {
|
|
// shuffle DestVec, (shuffle (fneg SrcVec), poison, SrcMask), Mask
|
|
Value *LenChgShuf = Builder.CreateShuffleVector(VecFNeg, SrcMask);
|
|
NewShuf = Builder.CreateShuffleVector(DestVec, LenChgShuf, Mask);
|
|
} else {
|
|
// shuffle DestVec, (fneg SrcVec), Mask
|
|
NewShuf = Builder.CreateShuffleVector(DestVec, VecFNeg, Mask);
|
|
}
|
|
|
|
replaceValue(I, *NewShuf);
|
|
return true;
|
|
}
|
|
|
|
/// If this is a bitcast of a shuffle, try to bitcast the source vector to the
|
|
/// destination type followed by shuffle. This can enable further transforms by
|
|
/// moving bitcasts or shuffles together.
|
|
bool VectorCombine::foldBitcastShuffle(Instruction &I) {
|
|
Value *V0, *V1;
|
|
ArrayRef<int> Mask;
|
|
if (!match(&I, m_BitCast(m_OneUse(
|
|
m_Shuffle(m_Value(V0), m_Value(V1), m_Mask(Mask))))))
|
|
return false;
|
|
|
|
// 1) Do not fold bitcast shuffle for scalable type. First, shuffle cost for
|
|
// scalable type is unknown; Second, we cannot reason if the narrowed shuffle
|
|
// mask for scalable type is a splat or not.
|
|
// 2) Disallow non-vector casts.
|
|
// TODO: We could allow any shuffle.
|
|
auto *DestTy = dyn_cast<FixedVectorType>(I.getType());
|
|
auto *SrcTy = dyn_cast<FixedVectorType>(V0->getType());
|
|
if (!DestTy || !SrcTy)
|
|
return false;
|
|
|
|
unsigned DestEltSize = DestTy->getScalarSizeInBits();
|
|
unsigned SrcEltSize = SrcTy->getScalarSizeInBits();
|
|
if (SrcTy->getPrimitiveSizeInBits() % DestEltSize != 0)
|
|
return false;
|
|
|
|
bool IsUnary = isa<UndefValue>(V1);
|
|
|
|
// For binary shuffles, only fold bitcast(shuffle(X,Y))
|
|
// if it won't increase the number of bitcasts.
|
|
if (!IsUnary) {
|
|
auto *BCTy0 = dyn_cast<FixedVectorType>(peekThroughBitcasts(V0)->getType());
|
|
auto *BCTy1 = dyn_cast<FixedVectorType>(peekThroughBitcasts(V1)->getType());
|
|
if (!(BCTy0 && BCTy0->getElementType() == DestTy->getElementType()) &&
|
|
!(BCTy1 && BCTy1->getElementType() == DestTy->getElementType()))
|
|
return false;
|
|
}
|
|
|
|
SmallVector<int, 16> NewMask;
|
|
if (DestEltSize <= SrcEltSize) {
|
|
// The bitcast is from wide to narrow/equal elements. The shuffle mask can
|
|
// always be expanded to the equivalent form choosing narrower elements.
|
|
assert(SrcEltSize % DestEltSize == 0 && "Unexpected shuffle mask");
|
|
unsigned ScaleFactor = SrcEltSize / DestEltSize;
|
|
narrowShuffleMaskElts(ScaleFactor, Mask, NewMask);
|
|
} else {
|
|
// The bitcast is from narrow elements to wide elements. The shuffle mask
|
|
// must choose consecutive elements to allow casting first.
|
|
assert(DestEltSize % SrcEltSize == 0 && "Unexpected shuffle mask");
|
|
unsigned ScaleFactor = DestEltSize / SrcEltSize;
|
|
if (!widenShuffleMaskElts(ScaleFactor, Mask, NewMask))
|
|
return false;
|
|
}
|
|
|
|
// Bitcast the shuffle src - keep its original width but using the destination
|
|
// scalar type.
|
|
unsigned NumSrcElts = SrcTy->getPrimitiveSizeInBits() / DestEltSize;
|
|
auto *NewShuffleTy =
|
|
FixedVectorType::get(DestTy->getScalarType(), NumSrcElts);
|
|
auto *OldShuffleTy =
|
|
FixedVectorType::get(SrcTy->getScalarType(), Mask.size());
|
|
unsigned NumOps = IsUnary ? 1 : 2;
|
|
|
|
// The new shuffle must not cost more than the old shuffle.
|
|
TargetTransformInfo::ShuffleKind SK =
|
|
IsUnary ? TargetTransformInfo::SK_PermuteSingleSrc
|
|
: TargetTransformInfo::SK_PermuteTwoSrc;
|
|
|
|
InstructionCost NewCost =
|
|
TTI.getShuffleCost(SK, NewShuffleTy, NewMask, CostKind) +
|
|
(NumOps * TTI.getCastInstrCost(Instruction::BitCast, NewShuffleTy, SrcTy,
|
|
TargetTransformInfo::CastContextHint::None,
|
|
CostKind));
|
|
InstructionCost OldCost =
|
|
TTI.getShuffleCost(SK, SrcTy, Mask, CostKind) +
|
|
TTI.getCastInstrCost(Instruction::BitCast, DestTy, OldShuffleTy,
|
|
TargetTransformInfo::CastContextHint::None,
|
|
CostKind);
|
|
|
|
LLVM_DEBUG(dbgs() << "Found a bitcasted shuffle: " << I << "\n OldCost: "
|
|
<< OldCost << " vs NewCost: " << NewCost << "\n");
|
|
|
|
if (NewCost > OldCost || !NewCost.isValid())
|
|
return false;
|
|
|
|
// bitcast (shuf V0, V1, MaskC) --> shuf (bitcast V0), (bitcast V1), MaskC'
|
|
++NumShufOfBitcast;
|
|
Value *CastV0 = Builder.CreateBitCast(peekThroughBitcasts(V0), NewShuffleTy);
|
|
Value *CastV1 = Builder.CreateBitCast(peekThroughBitcasts(V1), NewShuffleTy);
|
|
Value *Shuf = Builder.CreateShuffleVector(CastV0, CastV1, NewMask);
|
|
replaceValue(I, *Shuf);
|
|
return true;
|
|
}
|
|
|
|
/// VP Intrinsics whose vector operands are both splat values may be simplified
|
|
/// into the scalar version of the operation and the result splatted. This
|
|
/// can lead to scalarization down the line.
|
|
bool VectorCombine::scalarizeVPIntrinsic(Instruction &I) {
|
|
if (!isa<VPIntrinsic>(I))
|
|
return false;
|
|
VPIntrinsic &VPI = cast<VPIntrinsic>(I);
|
|
Value *Op0 = VPI.getArgOperand(0);
|
|
Value *Op1 = VPI.getArgOperand(1);
|
|
|
|
if (!isSplatValue(Op0) || !isSplatValue(Op1))
|
|
return false;
|
|
|
|
// Check getSplatValue early in this function, to avoid doing unnecessary
|
|
// work.
|
|
Value *ScalarOp0 = getSplatValue(Op0);
|
|
Value *ScalarOp1 = getSplatValue(Op1);
|
|
if (!ScalarOp0 || !ScalarOp1)
|
|
return false;
|
|
|
|
// For the binary VP intrinsics supported here, the result on disabled lanes
|
|
// is a poison value. For now, only do this simplification if all lanes
|
|
// are active.
|
|
// TODO: Relax the condition that all lanes are active by using insertelement
|
|
// on inactive lanes.
|
|
auto IsAllTrueMask = [](Value *MaskVal) {
|
|
if (Value *SplattedVal = getSplatValue(MaskVal))
|
|
if (auto *ConstValue = dyn_cast<Constant>(SplattedVal))
|
|
return ConstValue->isAllOnesValue();
|
|
return false;
|
|
};
|
|
if (!IsAllTrueMask(VPI.getArgOperand(2)))
|
|
return false;
|
|
|
|
// Check to make sure we support scalarization of the intrinsic
|
|
Intrinsic::ID IntrID = VPI.getIntrinsicID();
|
|
if (!VPBinOpIntrinsic::isVPBinOp(IntrID))
|
|
return false;
|
|
|
|
// Calculate cost of splatting both operands into vectors and the vector
|
|
// intrinsic
|
|
VectorType *VecTy = cast<VectorType>(VPI.getType());
|
|
SmallVector<int> Mask;
|
|
if (auto *FVTy = dyn_cast<FixedVectorType>(VecTy))
|
|
Mask.resize(FVTy->getNumElements(), 0);
|
|
InstructionCost SplatCost =
|
|
TTI.getVectorInstrCost(Instruction::InsertElement, VecTy, CostKind, 0) +
|
|
TTI.getShuffleCost(TargetTransformInfo::SK_Broadcast, VecTy, Mask,
|
|
CostKind);
|
|
|
|
// Calculate the cost of the VP Intrinsic
|
|
SmallVector<Type *, 4> Args;
|
|
for (Value *V : VPI.args())
|
|
Args.push_back(V->getType());
|
|
IntrinsicCostAttributes Attrs(IntrID, VecTy, Args);
|
|
InstructionCost VectorOpCost = TTI.getIntrinsicInstrCost(Attrs, CostKind);
|
|
InstructionCost OldCost = 2 * SplatCost + VectorOpCost;
|
|
|
|
// Determine scalar opcode
|
|
std::optional<unsigned> FunctionalOpcode =
|
|
VPI.getFunctionalOpcode();
|
|
std::optional<Intrinsic::ID> ScalarIntrID = std::nullopt;
|
|
if (!FunctionalOpcode) {
|
|
ScalarIntrID = VPI.getFunctionalIntrinsicID();
|
|
if (!ScalarIntrID)
|
|
return false;
|
|
}
|
|
|
|
// Calculate cost of scalarizing
|
|
InstructionCost ScalarOpCost = 0;
|
|
if (ScalarIntrID) {
|
|
IntrinsicCostAttributes Attrs(*ScalarIntrID, VecTy->getScalarType(), Args);
|
|
ScalarOpCost = TTI.getIntrinsicInstrCost(Attrs, CostKind);
|
|
} else {
|
|
ScalarOpCost = TTI.getArithmeticInstrCost(*FunctionalOpcode,
|
|
VecTy->getScalarType(), CostKind);
|
|
}
|
|
|
|
// The existing splats may be kept around if other instructions use them.
|
|
InstructionCost CostToKeepSplats =
|
|
(SplatCost * !Op0->hasOneUse()) + (SplatCost * !Op1->hasOneUse());
|
|
InstructionCost NewCost = ScalarOpCost + SplatCost + CostToKeepSplats;
|
|
|
|
LLVM_DEBUG(dbgs() << "Found a VP Intrinsic to scalarize: " << VPI
|
|
<< "\n");
|
|
LLVM_DEBUG(dbgs() << "Cost of Intrinsic: " << OldCost
|
|
<< ", Cost of scalarizing:" << NewCost << "\n");
|
|
|
|
// We want to scalarize unless the vector variant actually has lower cost.
|
|
if (OldCost < NewCost || !NewCost.isValid())
|
|
return false;
|
|
|
|
// Scalarize the intrinsic
|
|
ElementCount EC = cast<VectorType>(Op0->getType())->getElementCount();
|
|
Value *EVL = VPI.getArgOperand(3);
|
|
|
|
// If the VP op might introduce UB or poison, we can scalarize it provided
|
|
// that we know the EVL > 0: If the EVL is zero, then the original VP op
|
|
// becomes a no-op and thus won't be UB, so make sure we don't introduce UB by
|
|
// scalarizing it.
|
|
bool SafeToSpeculate;
|
|
if (ScalarIntrID)
|
|
SafeToSpeculate = Intrinsic::getAttributes(I.getContext(), *ScalarIntrID)
|
|
.hasFnAttr(Attribute::AttrKind::Speculatable);
|
|
else
|
|
SafeToSpeculate = isSafeToSpeculativelyExecuteWithOpcode(
|
|
*FunctionalOpcode, &VPI, nullptr, &AC, &DT);
|
|
if (!SafeToSpeculate &&
|
|
!isKnownNonZero(EVL, SimplifyQuery(*DL, &DT, &AC, &VPI)))
|
|
return false;
|
|
|
|
Value *ScalarVal =
|
|
ScalarIntrID
|
|
? Builder.CreateIntrinsic(VecTy->getScalarType(), *ScalarIntrID,
|
|
{ScalarOp0, ScalarOp1})
|
|
: Builder.CreateBinOp((Instruction::BinaryOps)(*FunctionalOpcode),
|
|
ScalarOp0, ScalarOp1);
|
|
|
|
replaceValue(VPI, *Builder.CreateVectorSplat(EC, ScalarVal));
|
|
return true;
|
|
}
|
|
|
|
/// Match a vector binop or compare instruction with at least one inserted
|
|
/// scalar operand and convert to scalar binop/cmp followed by insertelement.
|
|
bool VectorCombine::scalarizeBinopOrCmp(Instruction &I) {
|
|
CmpPredicate Pred = CmpInst::BAD_ICMP_PREDICATE;
|
|
Value *Ins0, *Ins1;
|
|
if (!match(&I, m_BinOp(m_Value(Ins0), m_Value(Ins1))) &&
|
|
!match(&I, m_Cmp(Pred, m_Value(Ins0), m_Value(Ins1))))
|
|
return false;
|
|
|
|
// Do not convert the vector condition of a vector select into a scalar
|
|
// condition. That may cause problems for codegen because of differences in
|
|
// boolean formats and register-file transfers.
|
|
// TODO: Can we account for that in the cost model?
|
|
bool IsCmp = Pred != CmpInst::Predicate::BAD_ICMP_PREDICATE;
|
|
if (IsCmp)
|
|
for (User *U : I.users())
|
|
if (match(U, m_Select(m_Specific(&I), m_Value(), m_Value())))
|
|
return false;
|
|
|
|
// Match against one or both scalar values being inserted into constant
|
|
// vectors:
|
|
// vec_op VecC0, (inselt VecC1, V1, Index)
|
|
// vec_op (inselt VecC0, V0, Index), VecC1
|
|
// vec_op (inselt VecC0, V0, Index), (inselt VecC1, V1, Index)
|
|
// TODO: Deal with mismatched index constants and variable indexes?
|
|
Constant *VecC0 = nullptr, *VecC1 = nullptr;
|
|
Value *V0 = nullptr, *V1 = nullptr;
|
|
uint64_t Index0 = 0, Index1 = 0;
|
|
if (!match(Ins0, m_InsertElt(m_Constant(VecC0), m_Value(V0),
|
|
m_ConstantInt(Index0))) &&
|
|
!match(Ins0, m_Constant(VecC0)))
|
|
return false;
|
|
if (!match(Ins1, m_InsertElt(m_Constant(VecC1), m_Value(V1),
|
|
m_ConstantInt(Index1))) &&
|
|
!match(Ins1, m_Constant(VecC1)))
|
|
return false;
|
|
|
|
bool IsConst0 = !V0;
|
|
bool IsConst1 = !V1;
|
|
if (IsConst0 && IsConst1)
|
|
return false;
|
|
if (!IsConst0 && !IsConst1 && Index0 != Index1)
|
|
return false;
|
|
|
|
auto *VecTy0 = cast<VectorType>(Ins0->getType());
|
|
auto *VecTy1 = cast<VectorType>(Ins1->getType());
|
|
if (VecTy0->getElementCount().getKnownMinValue() <= Index0 ||
|
|
VecTy1->getElementCount().getKnownMinValue() <= Index1)
|
|
return false;
|
|
|
|
// Bail for single insertion if it is a load.
|
|
// TODO: Handle this once getVectorInstrCost can cost for load/stores.
|
|
auto *I0 = dyn_cast_or_null<Instruction>(V0);
|
|
auto *I1 = dyn_cast_or_null<Instruction>(V1);
|
|
if ((IsConst0 && I1 && I1->mayReadFromMemory()) ||
|
|
(IsConst1 && I0 && I0->mayReadFromMemory()))
|
|
return false;
|
|
|
|
uint64_t Index = IsConst0 ? Index1 : Index0;
|
|
Type *ScalarTy = IsConst0 ? V1->getType() : V0->getType();
|
|
Type *VecTy = I.getType();
|
|
assert(VecTy->isVectorTy() &&
|
|
(IsConst0 || IsConst1 || V0->getType() == V1->getType()) &&
|
|
(ScalarTy->isIntegerTy() || ScalarTy->isFloatingPointTy() ||
|
|
ScalarTy->isPointerTy()) &&
|
|
"Unexpected types for insert element into binop or cmp");
|
|
|
|
unsigned Opcode = I.getOpcode();
|
|
InstructionCost ScalarOpCost, VectorOpCost;
|
|
if (IsCmp) {
|
|
CmpInst::Predicate Pred = cast<CmpInst>(I).getPredicate();
|
|
ScalarOpCost = TTI.getCmpSelInstrCost(
|
|
Opcode, ScalarTy, CmpInst::makeCmpResultType(ScalarTy), Pred, CostKind);
|
|
VectorOpCost = TTI.getCmpSelInstrCost(
|
|
Opcode, VecTy, CmpInst::makeCmpResultType(VecTy), Pred, CostKind);
|
|
} else {
|
|
ScalarOpCost = TTI.getArithmeticInstrCost(Opcode, ScalarTy, CostKind);
|
|
VectorOpCost = TTI.getArithmeticInstrCost(Opcode, VecTy, CostKind);
|
|
}
|
|
|
|
// Get cost estimate for the insert element. This cost will factor into
|
|
// both sequences.
|
|
InstructionCost InsertCost = TTI.getVectorInstrCost(
|
|
Instruction::InsertElement, VecTy, CostKind, Index);
|
|
InstructionCost OldCost =
|
|
(IsConst0 ? 0 : InsertCost) + (IsConst1 ? 0 : InsertCost) + VectorOpCost;
|
|
InstructionCost NewCost = ScalarOpCost + InsertCost +
|
|
(IsConst0 ? 0 : !Ins0->hasOneUse() * InsertCost) +
|
|
(IsConst1 ? 0 : !Ins1->hasOneUse() * InsertCost);
|
|
|
|
// We want to scalarize unless the vector variant actually has lower cost.
|
|
if (OldCost < NewCost || !NewCost.isValid())
|
|
return false;
|
|
|
|
// vec_op (inselt VecC0, V0, Index), (inselt VecC1, V1, Index) -->
|
|
// inselt NewVecC, (scalar_op V0, V1), Index
|
|
if (IsCmp)
|
|
++NumScalarCmp;
|
|
else
|
|
++NumScalarBO;
|
|
|
|
// For constant cases, extract the scalar element, this should constant fold.
|
|
if (IsConst0)
|
|
V0 = ConstantExpr::getExtractElement(VecC0, Builder.getInt64(Index));
|
|
if (IsConst1)
|
|
V1 = ConstantExpr::getExtractElement(VecC1, Builder.getInt64(Index));
|
|
|
|
Value *Scalar =
|
|
IsCmp ? Builder.CreateCmp(Pred, V0, V1)
|
|
: Builder.CreateBinOp((Instruction::BinaryOps)Opcode, V0, V1);
|
|
|
|
Scalar->setName(I.getName() + ".scalar");
|
|
|
|
// All IR flags are safe to back-propagate. There is no potential for extra
|
|
// poison to be created by the scalar instruction.
|
|
if (auto *ScalarInst = dyn_cast<Instruction>(Scalar))
|
|
ScalarInst->copyIRFlags(&I);
|
|
|
|
// Fold the vector constants in the original vectors into a new base vector.
|
|
Value *NewVecC =
|
|
IsCmp ? Builder.CreateCmp(Pred, VecC0, VecC1)
|
|
: Builder.CreateBinOp((Instruction::BinaryOps)Opcode, VecC0, VecC1);
|
|
Value *Insert = Builder.CreateInsertElement(NewVecC, Scalar, Index);
|
|
replaceValue(I, *Insert);
|
|
return true;
|
|
}
|
|
|
|
/// Try to combine a scalar binop + 2 scalar compares of extracted elements of
|
|
/// a vector into vector operations followed by extract. Note: The SLP pass
|
|
/// may miss this pattern because of implementation problems.
|
|
bool VectorCombine::foldExtractedCmps(Instruction &I) {
|
|
auto *BI = dyn_cast<BinaryOperator>(&I);
|
|
|
|
// We are looking for a scalar binop of booleans.
|
|
// binop i1 (cmp Pred I0, C0), (cmp Pred I1, C1)
|
|
if (!BI || !I.getType()->isIntegerTy(1))
|
|
return false;
|
|
|
|
// The compare predicates should match, and each compare should have a
|
|
// constant operand.
|
|
Value *B0 = I.getOperand(0), *B1 = I.getOperand(1);
|
|
Instruction *I0, *I1;
|
|
Constant *C0, *C1;
|
|
CmpPredicate P0, P1;
|
|
// FIXME: Use CmpPredicate::getMatching here.
|
|
if (!match(B0, m_Cmp(P0, m_Instruction(I0), m_Constant(C0))) ||
|
|
!match(B1, m_Cmp(P1, m_Instruction(I1), m_Constant(C1))) ||
|
|
P0 != static_cast<CmpInst::Predicate>(P1))
|
|
return false;
|
|
|
|
// The compare operands must be extracts of the same vector with constant
|
|
// extract indexes.
|
|
Value *X;
|
|
uint64_t Index0, Index1;
|
|
if (!match(I0, m_ExtractElt(m_Value(X), m_ConstantInt(Index0))) ||
|
|
!match(I1, m_ExtractElt(m_Specific(X), m_ConstantInt(Index1))))
|
|
return false;
|
|
|
|
auto *Ext0 = cast<ExtractElementInst>(I0);
|
|
auto *Ext1 = cast<ExtractElementInst>(I1);
|
|
ExtractElementInst *ConvertToShuf = getShuffleExtract(Ext0, Ext1, CostKind);
|
|
if (!ConvertToShuf)
|
|
return false;
|
|
assert((ConvertToShuf == Ext0 || ConvertToShuf == Ext1) &&
|
|
"Unknown ExtractElementInst");
|
|
|
|
// The original scalar pattern is:
|
|
// binop i1 (cmp Pred (ext X, Index0), C0), (cmp Pred (ext X, Index1), C1)
|
|
CmpInst::Predicate Pred = P0;
|
|
unsigned CmpOpcode =
|
|
CmpInst::isFPPredicate(Pred) ? Instruction::FCmp : Instruction::ICmp;
|
|
auto *VecTy = dyn_cast<FixedVectorType>(X->getType());
|
|
if (!VecTy)
|
|
return false;
|
|
|
|
InstructionCost Ext0Cost =
|
|
TTI.getVectorInstrCost(*Ext0, VecTy, CostKind, Index0);
|
|
InstructionCost Ext1Cost =
|
|
TTI.getVectorInstrCost(*Ext1, VecTy, CostKind, Index1);
|
|
InstructionCost CmpCost = TTI.getCmpSelInstrCost(
|
|
CmpOpcode, I0->getType(), CmpInst::makeCmpResultType(I0->getType()), Pred,
|
|
CostKind);
|
|
|
|
InstructionCost OldCost =
|
|
Ext0Cost + Ext1Cost + CmpCost * 2 +
|
|
TTI.getArithmeticInstrCost(I.getOpcode(), I.getType(), CostKind);
|
|
|
|
// The proposed vector pattern is:
|
|
// vcmp = cmp Pred X, VecC
|
|
// ext (binop vNi1 vcmp, (shuffle vcmp, Index1)), Index0
|
|
int CheapIndex = ConvertToShuf == Ext0 ? Index1 : Index0;
|
|
int ExpensiveIndex = ConvertToShuf == Ext0 ? Index0 : Index1;
|
|
auto *CmpTy = cast<FixedVectorType>(CmpInst::makeCmpResultType(X->getType()));
|
|
InstructionCost NewCost = TTI.getCmpSelInstrCost(
|
|
CmpOpcode, X->getType(), CmpInst::makeCmpResultType(X->getType()), Pred,
|
|
CostKind);
|
|
SmallVector<int, 32> ShufMask(VecTy->getNumElements(), PoisonMaskElem);
|
|
ShufMask[CheapIndex] = ExpensiveIndex;
|
|
NewCost += TTI.getShuffleCost(TargetTransformInfo::SK_PermuteSingleSrc, CmpTy,
|
|
ShufMask, CostKind);
|
|
NewCost += TTI.getArithmeticInstrCost(I.getOpcode(), CmpTy, CostKind);
|
|
NewCost += TTI.getVectorInstrCost(*Ext0, CmpTy, CostKind, CheapIndex);
|
|
NewCost += Ext0->hasOneUse() ? 0 : Ext0Cost;
|
|
NewCost += Ext1->hasOneUse() ? 0 : Ext1Cost;
|
|
|
|
// Aggressively form vector ops if the cost is equal because the transform
|
|
// may enable further optimization.
|
|
// Codegen can reverse this transform (scalarize) if it was not profitable.
|
|
if (OldCost < NewCost || !NewCost.isValid())
|
|
return false;
|
|
|
|
// Create a vector constant from the 2 scalar constants.
|
|
SmallVector<Constant *, 32> CmpC(VecTy->getNumElements(),
|
|
PoisonValue::get(VecTy->getElementType()));
|
|
CmpC[Index0] = C0;
|
|
CmpC[Index1] = C1;
|
|
Value *VCmp = Builder.CreateCmp(Pred, X, ConstantVector::get(CmpC));
|
|
Value *Shuf = createShiftShuffle(VCmp, ExpensiveIndex, CheapIndex, Builder);
|
|
Value *LHS = ConvertToShuf == Ext0 ? Shuf : VCmp;
|
|
Value *RHS = ConvertToShuf == Ext0 ? VCmp : Shuf;
|
|
Value *VecLogic = Builder.CreateBinOp(BI->getOpcode(), LHS, RHS);
|
|
Value *NewExt = Builder.CreateExtractElement(VecLogic, CheapIndex);
|
|
replaceValue(I, *NewExt);
|
|
++NumVecCmpBO;
|
|
return true;
|
|
}
|
|
|
|
// Check if memory loc modified between two instrs in the same BB
|
|
static bool isMemModifiedBetween(BasicBlock::iterator Begin,
|
|
BasicBlock::iterator End,
|
|
const MemoryLocation &Loc, AAResults &AA) {
|
|
unsigned NumScanned = 0;
|
|
return std::any_of(Begin, End, [&](const Instruction &Instr) {
|
|
return isModSet(AA.getModRefInfo(&Instr, Loc)) ||
|
|
++NumScanned > MaxInstrsToScan;
|
|
});
|
|
}
|
|
|
|
namespace {
|
|
/// Helper class to indicate whether a vector index can be safely scalarized and
|
|
/// if a freeze needs to be inserted.
|
|
class ScalarizationResult {
|
|
enum class StatusTy { Unsafe, Safe, SafeWithFreeze };
|
|
|
|
StatusTy Status;
|
|
Value *ToFreeze;
|
|
|
|
ScalarizationResult(StatusTy Status, Value *ToFreeze = nullptr)
|
|
: Status(Status), ToFreeze(ToFreeze) {}
|
|
|
|
public:
|
|
ScalarizationResult(const ScalarizationResult &Other) = default;
|
|
~ScalarizationResult() {
|
|
assert(!ToFreeze && "freeze() not called with ToFreeze being set");
|
|
}
|
|
|
|
static ScalarizationResult unsafe() { return {StatusTy::Unsafe}; }
|
|
static ScalarizationResult safe() { return {StatusTy::Safe}; }
|
|
static ScalarizationResult safeWithFreeze(Value *ToFreeze) {
|
|
return {StatusTy::SafeWithFreeze, ToFreeze};
|
|
}
|
|
|
|
/// Returns true if the index can be scalarize without requiring a freeze.
|
|
bool isSafe() const { return Status == StatusTy::Safe; }
|
|
/// Returns true if the index cannot be scalarized.
|
|
bool isUnsafe() const { return Status == StatusTy::Unsafe; }
|
|
/// Returns true if the index can be scalarize, but requires inserting a
|
|
/// freeze.
|
|
bool isSafeWithFreeze() const { return Status == StatusTy::SafeWithFreeze; }
|
|
|
|
/// Reset the state of Unsafe and clear ToFreze if set.
|
|
void discard() {
|
|
ToFreeze = nullptr;
|
|
Status = StatusTy::Unsafe;
|
|
}
|
|
|
|
/// Freeze the ToFreeze and update the use in \p User to use it.
|
|
void freeze(IRBuilder<> &Builder, Instruction &UserI) {
|
|
assert(isSafeWithFreeze() &&
|
|
"should only be used when freezing is required");
|
|
assert(is_contained(ToFreeze->users(), &UserI) &&
|
|
"UserI must be a user of ToFreeze");
|
|
IRBuilder<>::InsertPointGuard Guard(Builder);
|
|
Builder.SetInsertPoint(cast<Instruction>(&UserI));
|
|
Value *Frozen =
|
|
Builder.CreateFreeze(ToFreeze, ToFreeze->getName() + ".frozen");
|
|
for (Use &U : make_early_inc_range((UserI.operands())))
|
|
if (U.get() == ToFreeze)
|
|
U.set(Frozen);
|
|
|
|
ToFreeze = nullptr;
|
|
}
|
|
};
|
|
} // namespace
|
|
|
|
/// Check if it is legal to scalarize a memory access to \p VecTy at index \p
|
|
/// Idx. \p Idx must access a valid vector element.
|
|
static ScalarizationResult canScalarizeAccess(VectorType *VecTy, Value *Idx,
|
|
Instruction *CtxI,
|
|
AssumptionCache &AC,
|
|
const DominatorTree &DT) {
|
|
// We do checks for both fixed vector types and scalable vector types.
|
|
// This is the number of elements of fixed vector types,
|
|
// or the minimum number of elements of scalable vector types.
|
|
uint64_t NumElements = VecTy->getElementCount().getKnownMinValue();
|
|
|
|
if (auto *C = dyn_cast<ConstantInt>(Idx)) {
|
|
if (C->getValue().ult(NumElements))
|
|
return ScalarizationResult::safe();
|
|
return ScalarizationResult::unsafe();
|
|
}
|
|
|
|
unsigned IntWidth = Idx->getType()->getScalarSizeInBits();
|
|
APInt Zero(IntWidth, 0);
|
|
APInt MaxElts(IntWidth, NumElements);
|
|
ConstantRange ValidIndices(Zero, MaxElts);
|
|
ConstantRange IdxRange(IntWidth, true);
|
|
|
|
if (isGuaranteedNotToBePoison(Idx, &AC)) {
|
|
if (ValidIndices.contains(computeConstantRange(Idx, /* ForSigned */ false,
|
|
true, &AC, CtxI, &DT)))
|
|
return ScalarizationResult::safe();
|
|
return ScalarizationResult::unsafe();
|
|
}
|
|
|
|
// If the index may be poison, check if we can insert a freeze before the
|
|
// range of the index is restricted.
|
|
Value *IdxBase;
|
|
ConstantInt *CI;
|
|
if (match(Idx, m_And(m_Value(IdxBase), m_ConstantInt(CI)))) {
|
|
IdxRange = IdxRange.binaryAnd(CI->getValue());
|
|
} else if (match(Idx, m_URem(m_Value(IdxBase), m_ConstantInt(CI)))) {
|
|
IdxRange = IdxRange.urem(CI->getValue());
|
|
}
|
|
|
|
if (ValidIndices.contains(IdxRange))
|
|
return ScalarizationResult::safeWithFreeze(IdxBase);
|
|
return ScalarizationResult::unsafe();
|
|
}
|
|
|
|
/// The memory operation on a vector of \p ScalarType had alignment of
|
|
/// \p VectorAlignment. Compute the maximal, but conservatively correct,
|
|
/// alignment that will be valid for the memory operation on a single scalar
|
|
/// element of the same type with index \p Idx.
|
|
static Align computeAlignmentAfterScalarization(Align VectorAlignment,
|
|
Type *ScalarType, Value *Idx,
|
|
const DataLayout &DL) {
|
|
if (auto *C = dyn_cast<ConstantInt>(Idx))
|
|
return commonAlignment(VectorAlignment,
|
|
C->getZExtValue() * DL.getTypeStoreSize(ScalarType));
|
|
return commonAlignment(VectorAlignment, DL.getTypeStoreSize(ScalarType));
|
|
}
|
|
|
|
// Combine patterns like:
|
|
// %0 = load <4 x i32>, <4 x i32>* %a
|
|
// %1 = insertelement <4 x i32> %0, i32 %b, i32 1
|
|
// store <4 x i32> %1, <4 x i32>* %a
|
|
// to:
|
|
// %0 = bitcast <4 x i32>* %a to i32*
|
|
// %1 = getelementptr inbounds i32, i32* %0, i64 0, i64 1
|
|
// store i32 %b, i32* %1
|
|
bool VectorCombine::foldSingleElementStore(Instruction &I) {
|
|
auto *SI = cast<StoreInst>(&I);
|
|
if (!SI->isSimple() || !isa<VectorType>(SI->getValueOperand()->getType()))
|
|
return false;
|
|
|
|
// TODO: Combine more complicated patterns (multiple insert) by referencing
|
|
// TargetTransformInfo.
|
|
Instruction *Source;
|
|
Value *NewElement;
|
|
Value *Idx;
|
|
if (!match(SI->getValueOperand(),
|
|
m_InsertElt(m_Instruction(Source), m_Value(NewElement),
|
|
m_Value(Idx))))
|
|
return false;
|
|
|
|
if (auto *Load = dyn_cast<LoadInst>(Source)) {
|
|
auto VecTy = cast<VectorType>(SI->getValueOperand()->getType());
|
|
Value *SrcAddr = Load->getPointerOperand()->stripPointerCasts();
|
|
// Don't optimize for atomic/volatile load or store. Ensure memory is not
|
|
// modified between, vector type matches store size, and index is inbounds.
|
|
if (!Load->isSimple() || Load->getParent() != SI->getParent() ||
|
|
!DL->typeSizeEqualsStoreSize(Load->getType()->getScalarType()) ||
|
|
SrcAddr != SI->getPointerOperand()->stripPointerCasts())
|
|
return false;
|
|
|
|
auto ScalarizableIdx = canScalarizeAccess(VecTy, Idx, Load, AC, DT);
|
|
if (ScalarizableIdx.isUnsafe() ||
|
|
isMemModifiedBetween(Load->getIterator(), SI->getIterator(),
|
|
MemoryLocation::get(SI), AA))
|
|
return false;
|
|
|
|
// Ensure we add the load back to the worklist BEFORE its users so they can
|
|
// erased in the correct order.
|
|
Worklist.push(Load);
|
|
|
|
if (ScalarizableIdx.isSafeWithFreeze())
|
|
ScalarizableIdx.freeze(Builder, *cast<Instruction>(Idx));
|
|
Value *GEP = Builder.CreateInBoundsGEP(
|
|
SI->getValueOperand()->getType(), SI->getPointerOperand(),
|
|
{ConstantInt::get(Idx->getType(), 0), Idx});
|
|
StoreInst *NSI = Builder.CreateStore(NewElement, GEP);
|
|
NSI->copyMetadata(*SI);
|
|
Align ScalarOpAlignment = computeAlignmentAfterScalarization(
|
|
std::max(SI->getAlign(), Load->getAlign()), NewElement->getType(), Idx,
|
|
*DL);
|
|
NSI->setAlignment(ScalarOpAlignment);
|
|
replaceValue(I, *NSI);
|
|
eraseInstruction(I);
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/// Try to scalarize vector loads feeding extractelement instructions.
|
|
bool VectorCombine::scalarizeLoadExtract(Instruction &I) {
|
|
Value *Ptr;
|
|
if (!match(&I, m_Load(m_Value(Ptr))))
|
|
return false;
|
|
|
|
auto *LI = cast<LoadInst>(&I);
|
|
auto *VecTy = cast<VectorType>(LI->getType());
|
|
if (LI->isVolatile() || !DL->typeSizeEqualsStoreSize(VecTy->getScalarType()))
|
|
return false;
|
|
|
|
InstructionCost OriginalCost =
|
|
TTI.getMemoryOpCost(Instruction::Load, VecTy, LI->getAlign(),
|
|
LI->getPointerAddressSpace(), CostKind);
|
|
InstructionCost ScalarizedCost = 0;
|
|
|
|
Instruction *LastCheckedInst = LI;
|
|
unsigned NumInstChecked = 0;
|
|
DenseMap<ExtractElementInst *, ScalarizationResult> NeedFreeze;
|
|
auto FailureGuard = make_scope_exit([&]() {
|
|
// If the transform is aborted, discard the ScalarizationResults.
|
|
for (auto &Pair : NeedFreeze)
|
|
Pair.second.discard();
|
|
});
|
|
|
|
// Check if all users of the load are extracts with no memory modifications
|
|
// between the load and the extract. Compute the cost of both the original
|
|
// code and the scalarized version.
|
|
for (User *U : LI->users()) {
|
|
auto *UI = dyn_cast<ExtractElementInst>(U);
|
|
if (!UI || UI->getParent() != LI->getParent())
|
|
return false;
|
|
|
|
// Check if any instruction between the load and the extract may modify
|
|
// memory.
|
|
if (LastCheckedInst->comesBefore(UI)) {
|
|
for (Instruction &I :
|
|
make_range(std::next(LI->getIterator()), UI->getIterator())) {
|
|
// Bail out if we reached the check limit or the instruction may write
|
|
// to memory.
|
|
if (NumInstChecked == MaxInstrsToScan || I.mayWriteToMemory())
|
|
return false;
|
|
NumInstChecked++;
|
|
}
|
|
LastCheckedInst = UI;
|
|
}
|
|
|
|
auto ScalarIdx =
|
|
canScalarizeAccess(VecTy, UI->getIndexOperand(), LI, AC, DT);
|
|
if (ScalarIdx.isUnsafe())
|
|
return false;
|
|
if (ScalarIdx.isSafeWithFreeze()) {
|
|
NeedFreeze.try_emplace(UI, ScalarIdx);
|
|
ScalarIdx.discard();
|
|
}
|
|
|
|
auto *Index = dyn_cast<ConstantInt>(UI->getIndexOperand());
|
|
OriginalCost +=
|
|
TTI.getVectorInstrCost(Instruction::ExtractElement, VecTy, CostKind,
|
|
Index ? Index->getZExtValue() : -1);
|
|
ScalarizedCost +=
|
|
TTI.getMemoryOpCost(Instruction::Load, VecTy->getElementType(),
|
|
Align(1), LI->getPointerAddressSpace(), CostKind);
|
|
ScalarizedCost += TTI.getAddressComputationCost(VecTy->getElementType());
|
|
}
|
|
|
|
if (ScalarizedCost >= OriginalCost)
|
|
return false;
|
|
|
|
// Ensure we add the load back to the worklist BEFORE its users so they can
|
|
// erased in the correct order.
|
|
Worklist.push(LI);
|
|
|
|
// Replace extracts with narrow scalar loads.
|
|
for (User *U : LI->users()) {
|
|
auto *EI = cast<ExtractElementInst>(U);
|
|
Value *Idx = EI->getIndexOperand();
|
|
|
|
// Insert 'freeze' for poison indexes.
|
|
auto It = NeedFreeze.find(EI);
|
|
if (It != NeedFreeze.end())
|
|
It->second.freeze(Builder, *cast<Instruction>(Idx));
|
|
|
|
Builder.SetInsertPoint(EI);
|
|
Value *GEP =
|
|
Builder.CreateInBoundsGEP(VecTy, Ptr, {Builder.getInt32(0), Idx});
|
|
auto *NewLoad = cast<LoadInst>(Builder.CreateLoad(
|
|
VecTy->getElementType(), GEP, EI->getName() + ".scalar"));
|
|
|
|
Align ScalarOpAlignment = computeAlignmentAfterScalarization(
|
|
LI->getAlign(), VecTy->getElementType(), Idx, *DL);
|
|
NewLoad->setAlignment(ScalarOpAlignment);
|
|
|
|
replaceValue(*EI, *NewLoad);
|
|
}
|
|
|
|
FailureGuard.release();
|
|
return true;
|
|
}
|
|
|
|
/// Try to fold "(or (zext (bitcast X)), (shl (zext (bitcast Y)), C))"
|
|
/// to "(bitcast (concat X, Y))"
|
|
/// where X/Y are bitcasted from i1 mask vectors.
|
|
bool VectorCombine::foldConcatOfBoolMasks(Instruction &I) {
|
|
Type *Ty = I.getType();
|
|
if (!Ty->isIntegerTy())
|
|
return false;
|
|
|
|
// TODO: Add big endian test coverage
|
|
if (DL->isBigEndian())
|
|
return false;
|
|
|
|
// Restrict to disjoint cases so the mask vectors aren't overlapping.
|
|
Instruction *X, *Y;
|
|
if (!match(&I, m_DisjointOr(m_Instruction(X), m_Instruction(Y))))
|
|
return false;
|
|
|
|
// Allow both sources to contain shl, to handle more generic pattern:
|
|
// "(or (shl (zext (bitcast X)), C1), (shl (zext (bitcast Y)), C2))"
|
|
Value *SrcX;
|
|
uint64_t ShAmtX = 0;
|
|
if (!match(X, m_OneUse(m_ZExt(m_OneUse(m_BitCast(m_Value(SrcX)))))) &&
|
|
!match(X, m_OneUse(
|
|
m_Shl(m_OneUse(m_ZExt(m_OneUse(m_BitCast(m_Value(SrcX))))),
|
|
m_ConstantInt(ShAmtX)))))
|
|
return false;
|
|
|
|
Value *SrcY;
|
|
uint64_t ShAmtY = 0;
|
|
if (!match(Y, m_OneUse(m_ZExt(m_OneUse(m_BitCast(m_Value(SrcY)))))) &&
|
|
!match(Y, m_OneUse(
|
|
m_Shl(m_OneUse(m_ZExt(m_OneUse(m_BitCast(m_Value(SrcY))))),
|
|
m_ConstantInt(ShAmtY)))))
|
|
return false;
|
|
|
|
// Canonicalize larger shift to the RHS.
|
|
if (ShAmtX > ShAmtY) {
|
|
std::swap(X, Y);
|
|
std::swap(SrcX, SrcY);
|
|
std::swap(ShAmtX, ShAmtY);
|
|
}
|
|
|
|
// Ensure both sources are matching vXi1 bool mask types, and that the shift
|
|
// difference is the mask width so they can be easily concatenated together.
|
|
uint64_t ShAmtDiff = ShAmtY - ShAmtX;
|
|
unsigned NumSHL = (ShAmtX > 0) + (ShAmtY > 0);
|
|
unsigned BitWidth = Ty->getPrimitiveSizeInBits();
|
|
auto *MaskTy = dyn_cast<FixedVectorType>(SrcX->getType());
|
|
if (!MaskTy || SrcX->getType() != SrcY->getType() ||
|
|
!MaskTy->getElementType()->isIntegerTy(1) ||
|
|
MaskTy->getNumElements() != ShAmtDiff ||
|
|
MaskTy->getNumElements() > (BitWidth / 2))
|
|
return false;
|
|
|
|
auto *ConcatTy = FixedVectorType::getDoubleElementsVectorType(MaskTy);
|
|
auto *ConcatIntTy =
|
|
Type::getIntNTy(Ty->getContext(), ConcatTy->getNumElements());
|
|
auto *MaskIntTy = Type::getIntNTy(Ty->getContext(), ShAmtDiff);
|
|
|
|
SmallVector<int, 32> ConcatMask(ConcatTy->getNumElements());
|
|
std::iota(ConcatMask.begin(), ConcatMask.end(), 0);
|
|
|
|
// TODO: Is it worth supporting multi use cases?
|
|
InstructionCost OldCost = 0;
|
|
OldCost += TTI.getArithmeticInstrCost(Instruction::Or, Ty, CostKind);
|
|
OldCost +=
|
|
NumSHL * TTI.getArithmeticInstrCost(Instruction::Shl, Ty, CostKind);
|
|
OldCost += 2 * TTI.getCastInstrCost(Instruction::ZExt, Ty, MaskIntTy,
|
|
TTI::CastContextHint::None, CostKind);
|
|
OldCost += 2 * TTI.getCastInstrCost(Instruction::BitCast, MaskIntTy, MaskTy,
|
|
TTI::CastContextHint::None, CostKind);
|
|
|
|
InstructionCost NewCost = 0;
|
|
NewCost += TTI.getShuffleCost(TargetTransformInfo::SK_PermuteTwoSrc, MaskTy,
|
|
ConcatMask, CostKind);
|
|
NewCost += TTI.getCastInstrCost(Instruction::BitCast, ConcatIntTy, ConcatTy,
|
|
TTI::CastContextHint::None, CostKind);
|
|
if (Ty != ConcatIntTy)
|
|
NewCost += TTI.getCastInstrCost(Instruction::ZExt, Ty, ConcatIntTy,
|
|
TTI::CastContextHint::None, CostKind);
|
|
if (ShAmtX > 0)
|
|
NewCost += TTI.getArithmeticInstrCost(Instruction::Shl, Ty, CostKind);
|
|
|
|
LLVM_DEBUG(dbgs() << "Found a concatenation of bitcasted bool masks: " << I
|
|
<< "\n OldCost: " << OldCost << " vs NewCost: " << NewCost
|
|
<< "\n");
|
|
|
|
if (NewCost > OldCost)
|
|
return false;
|
|
|
|
// Build bool mask concatenation, bitcast back to scalar integer, and perform
|
|
// any residual zero-extension or shifting.
|
|
Value *Concat = Builder.CreateShuffleVector(SrcX, SrcY, ConcatMask);
|
|
Worklist.pushValue(Concat);
|
|
|
|
Value *Result = Builder.CreateBitCast(Concat, ConcatIntTy);
|
|
|
|
if (Ty != ConcatIntTy) {
|
|
Worklist.pushValue(Result);
|
|
Result = Builder.CreateZExt(Result, Ty);
|
|
}
|
|
|
|
if (ShAmtX > 0) {
|
|
Worklist.pushValue(Result);
|
|
Result = Builder.CreateShl(Result, ShAmtX);
|
|
}
|
|
|
|
replaceValue(I, *Result);
|
|
return true;
|
|
}
|
|
|
|
/// Try to convert "shuffle (binop (shuffle, shuffle)), undef"
|
|
/// --> "binop (shuffle), (shuffle)".
|
|
bool VectorCombine::foldPermuteOfBinops(Instruction &I) {
|
|
BinaryOperator *BinOp;
|
|
ArrayRef<int> OuterMask;
|
|
if (!match(&I,
|
|
m_Shuffle(m_OneUse(m_BinOp(BinOp)), m_Undef(), m_Mask(OuterMask))))
|
|
return false;
|
|
|
|
// Don't introduce poison into div/rem.
|
|
if (BinOp->isIntDivRem() && llvm::is_contained(OuterMask, PoisonMaskElem))
|
|
return false;
|
|
|
|
Value *Op00, *Op01, *Op10, *Op11;
|
|
ArrayRef<int> Mask0, Mask1;
|
|
bool Match0 =
|
|
match(BinOp->getOperand(0),
|
|
m_OneUse(m_Shuffle(m_Value(Op00), m_Value(Op01), m_Mask(Mask0))));
|
|
bool Match1 =
|
|
match(BinOp->getOperand(1),
|
|
m_OneUse(m_Shuffle(m_Value(Op10), m_Value(Op11), m_Mask(Mask1))));
|
|
if (!Match0 && !Match1)
|
|
return false;
|
|
|
|
Op00 = Match0 ? Op00 : BinOp->getOperand(0);
|
|
Op01 = Match0 ? Op01 : BinOp->getOperand(0);
|
|
Op10 = Match1 ? Op10 : BinOp->getOperand(1);
|
|
Op11 = Match1 ? Op11 : BinOp->getOperand(1);
|
|
|
|
Instruction::BinaryOps Opcode = BinOp->getOpcode();
|
|
auto *ShuffleDstTy = dyn_cast<FixedVectorType>(I.getType());
|
|
auto *BinOpTy = dyn_cast<FixedVectorType>(BinOp->getType());
|
|
auto *Op0Ty = dyn_cast<FixedVectorType>(Op00->getType());
|
|
auto *Op1Ty = dyn_cast<FixedVectorType>(Op10->getType());
|
|
if (!ShuffleDstTy || !BinOpTy || !Op0Ty || !Op1Ty)
|
|
return false;
|
|
|
|
unsigned NumSrcElts = BinOpTy->getNumElements();
|
|
|
|
// Don't accept shuffles that reference the second operand in
|
|
// div/rem or if its an undef arg.
|
|
if ((BinOp->isIntDivRem() || !isa<PoisonValue>(I.getOperand(1))) &&
|
|
any_of(OuterMask, [NumSrcElts](int M) { return M >= (int)NumSrcElts; }))
|
|
return false;
|
|
|
|
// Merge outer / inner (or identity if no match) shuffles.
|
|
SmallVector<int> NewMask0, NewMask1;
|
|
for (int M : OuterMask) {
|
|
if (M < 0 || M >= (int)NumSrcElts) {
|
|
NewMask0.push_back(PoisonMaskElem);
|
|
NewMask1.push_back(PoisonMaskElem);
|
|
} else {
|
|
NewMask0.push_back(Match0 ? Mask0[M] : M);
|
|
NewMask1.push_back(Match1 ? Mask1[M] : M);
|
|
}
|
|
}
|
|
|
|
unsigned NumOpElts = Op0Ty->getNumElements();
|
|
bool IsIdentity0 = ShuffleVectorInst::isIdentityMask(NewMask0, NumOpElts);
|
|
bool IsIdentity1 = ShuffleVectorInst::isIdentityMask(NewMask1, NumOpElts);
|
|
|
|
// Try to merge shuffles across the binop if the new shuffles are not costly.
|
|
InstructionCost OldCost =
|
|
TTI.getArithmeticInstrCost(Opcode, BinOpTy, CostKind) +
|
|
TTI.getShuffleCost(TargetTransformInfo::SK_PermuteSingleSrc, BinOpTy,
|
|
OuterMask, CostKind, 0, nullptr, {BinOp}, &I);
|
|
if (Match0)
|
|
OldCost += TTI.getShuffleCost(TargetTransformInfo::SK_PermuteTwoSrc, Op0Ty,
|
|
Mask0, CostKind, 0, nullptr, {Op00, Op01},
|
|
cast<Instruction>(BinOp->getOperand(0)));
|
|
if (Match1)
|
|
OldCost += TTI.getShuffleCost(TargetTransformInfo::SK_PermuteTwoSrc, Op1Ty,
|
|
Mask1, CostKind, 0, nullptr, {Op10, Op11},
|
|
cast<Instruction>(BinOp->getOperand(1)));
|
|
|
|
InstructionCost NewCost =
|
|
TTI.getArithmeticInstrCost(Opcode, ShuffleDstTy, CostKind);
|
|
|
|
if (!IsIdentity0)
|
|
NewCost += TTI.getShuffleCost(TargetTransformInfo::SK_PermuteTwoSrc, Op0Ty,
|
|
NewMask0, CostKind, 0, nullptr, {Op00, Op01});
|
|
if (!IsIdentity1)
|
|
NewCost += TTI.getShuffleCost(TargetTransformInfo::SK_PermuteTwoSrc, Op1Ty,
|
|
NewMask1, CostKind, 0, nullptr, {Op10, Op11});
|
|
|
|
LLVM_DEBUG(dbgs() << "Found a shuffle feeding a shuffled binop: " << I
|
|
<< "\n OldCost: " << OldCost << " vs NewCost: " << NewCost
|
|
<< "\n");
|
|
|
|
// If costs are equal, still fold as we reduce instruction count.
|
|
if (NewCost > OldCost)
|
|
return false;
|
|
|
|
Value *LHS =
|
|
IsIdentity0 ? Op00 : Builder.CreateShuffleVector(Op00, Op01, NewMask0);
|
|
Value *RHS =
|
|
IsIdentity1 ? Op10 : Builder.CreateShuffleVector(Op10, Op11, NewMask1);
|
|
Value *NewBO = Builder.CreateBinOp(Opcode, LHS, RHS);
|
|
|
|
// Intersect flags from the old binops.
|
|
if (auto *NewInst = dyn_cast<Instruction>(NewBO))
|
|
NewInst->copyIRFlags(BinOp);
|
|
|
|
Worklist.pushValue(LHS);
|
|
Worklist.pushValue(RHS);
|
|
replaceValue(I, *NewBO);
|
|
return true;
|
|
}
|
|
|
|
/// Try to convert "shuffle (binop), (binop)" into "binop (shuffle), (shuffle)".
|
|
/// Try to convert "shuffle (cmpop), (cmpop)" into "cmpop (shuffle), (shuffle)".
|
|
bool VectorCombine::foldShuffleOfBinops(Instruction &I) {
|
|
ArrayRef<int> OldMask;
|
|
Instruction *LHS, *RHS;
|
|
if (!match(&I, m_Shuffle(m_OneUse(m_Instruction(LHS)),
|
|
m_OneUse(m_Instruction(RHS)), m_Mask(OldMask))))
|
|
return false;
|
|
|
|
// TODO: Add support for addlike etc.
|
|
if (LHS->getOpcode() != RHS->getOpcode())
|
|
return false;
|
|
|
|
Value *X, *Y, *Z, *W;
|
|
bool IsCommutative = false;
|
|
CmpPredicate PredLHS = CmpInst::BAD_ICMP_PREDICATE;
|
|
CmpPredicate PredRHS = CmpInst::BAD_ICMP_PREDICATE;
|
|
if (match(LHS, m_BinOp(m_Value(X), m_Value(Y))) &&
|
|
match(RHS, m_BinOp(m_Value(Z), m_Value(W)))) {
|
|
auto *BO = cast<BinaryOperator>(LHS);
|
|
// Don't introduce poison into div/rem.
|
|
if (llvm::is_contained(OldMask, PoisonMaskElem) && BO->isIntDivRem())
|
|
return false;
|
|
IsCommutative = BinaryOperator::isCommutative(BO->getOpcode());
|
|
} else if (match(LHS, m_Cmp(PredLHS, m_Value(X), m_Value(Y))) &&
|
|
match(RHS, m_Cmp(PredRHS, m_Value(Z), m_Value(W))) &&
|
|
(CmpInst::Predicate)PredLHS == (CmpInst::Predicate)PredRHS) {
|
|
IsCommutative = cast<CmpInst>(LHS)->isCommutative();
|
|
} else
|
|
return false;
|
|
|
|
auto *ShuffleDstTy = dyn_cast<FixedVectorType>(I.getType());
|
|
auto *BinResTy = dyn_cast<FixedVectorType>(LHS->getType());
|
|
auto *BinOpTy = dyn_cast<FixedVectorType>(X->getType());
|
|
if (!ShuffleDstTy || !BinResTy || !BinOpTy || X->getType() != Z->getType())
|
|
return false;
|
|
|
|
unsigned NumSrcElts = BinOpTy->getNumElements();
|
|
|
|
// If we have something like "add X, Y" and "add Z, X", swap ops to match.
|
|
if (IsCommutative && X != Z && Y != W && (X == W || Y == Z))
|
|
std::swap(X, Y);
|
|
|
|
auto ConvertToUnary = [NumSrcElts](int &M) {
|
|
if (M >= (int)NumSrcElts)
|
|
M -= NumSrcElts;
|
|
};
|
|
|
|
SmallVector<int> NewMask0(OldMask);
|
|
TargetTransformInfo::ShuffleKind SK0 = TargetTransformInfo::SK_PermuteTwoSrc;
|
|
if (X == Z) {
|
|
llvm::for_each(NewMask0, ConvertToUnary);
|
|
SK0 = TargetTransformInfo::SK_PermuteSingleSrc;
|
|
Z = PoisonValue::get(BinOpTy);
|
|
}
|
|
|
|
SmallVector<int> NewMask1(OldMask);
|
|
TargetTransformInfo::ShuffleKind SK1 = TargetTransformInfo::SK_PermuteTwoSrc;
|
|
if (Y == W) {
|
|
llvm::for_each(NewMask1, ConvertToUnary);
|
|
SK1 = TargetTransformInfo::SK_PermuteSingleSrc;
|
|
W = PoisonValue::get(BinOpTy);
|
|
}
|
|
|
|
// Try to replace a binop with a shuffle if the shuffle is not costly.
|
|
InstructionCost OldCost =
|
|
TTI.getInstructionCost(LHS, CostKind) +
|
|
TTI.getInstructionCost(RHS, CostKind) +
|
|
TTI.getShuffleCost(TargetTransformInfo::SK_PermuteTwoSrc, BinResTy,
|
|
OldMask, CostKind, 0, nullptr, {LHS, RHS}, &I);
|
|
|
|
// Handle shuffle(binop(shuffle(x),y),binop(z,shuffle(w))) style patterns
|
|
// where one use shuffles have gotten split across the binop/cmp. These
|
|
// often allow a major reduction in total cost that wouldn't happen as
|
|
// individual folds.
|
|
auto MergeInner = [&](Value *&Op, int Offset, MutableArrayRef<int> Mask,
|
|
TTI::TargetCostKind CostKind) -> bool {
|
|
Value *InnerOp;
|
|
ArrayRef<int> InnerMask;
|
|
if (match(Op, m_OneUse(m_Shuffle(m_Value(InnerOp), m_Undef(),
|
|
m_Mask(InnerMask)))) &&
|
|
InnerOp->getType() == Op->getType() &&
|
|
all_of(InnerMask,
|
|
[NumSrcElts](int M) { return M < (int)NumSrcElts; })) {
|
|
for (int &M : Mask)
|
|
if (Offset <= M && M < (int)(Offset + NumSrcElts)) {
|
|
M = InnerMask[M - Offset];
|
|
M = 0 <= M ? M + Offset : M;
|
|
}
|
|
OldCost += TTI.getInstructionCost(cast<Instruction>(Op), CostKind);
|
|
Op = InnerOp;
|
|
return true;
|
|
}
|
|
return false;
|
|
};
|
|
bool ReducedInstCount = false;
|
|
ReducedInstCount |= MergeInner(X, 0, NewMask0, CostKind);
|
|
ReducedInstCount |= MergeInner(Y, 0, NewMask1, CostKind);
|
|
ReducedInstCount |= MergeInner(Z, NumSrcElts, NewMask0, CostKind);
|
|
ReducedInstCount |= MergeInner(W, NumSrcElts, NewMask1, CostKind);
|
|
|
|
InstructionCost NewCost =
|
|
TTI.getShuffleCost(SK0, BinOpTy, NewMask0, CostKind, 0, nullptr, {X, Z}) +
|
|
TTI.getShuffleCost(SK1, BinOpTy, NewMask1, CostKind, 0, nullptr, {Y, W});
|
|
|
|
if (PredLHS == CmpInst::BAD_ICMP_PREDICATE) {
|
|
NewCost +=
|
|
TTI.getArithmeticInstrCost(LHS->getOpcode(), ShuffleDstTy, CostKind);
|
|
} else {
|
|
auto *ShuffleCmpTy =
|
|
FixedVectorType::get(BinOpTy->getElementType(), ShuffleDstTy);
|
|
NewCost += TTI.getCmpSelInstrCost(LHS->getOpcode(), ShuffleCmpTy,
|
|
ShuffleDstTy, PredLHS, CostKind);
|
|
}
|
|
|
|
LLVM_DEBUG(dbgs() << "Found a shuffle feeding two binops: " << I
|
|
<< "\n OldCost: " << OldCost << " vs NewCost: " << NewCost
|
|
<< "\n");
|
|
|
|
// If either shuffle will constant fold away, then fold for the same cost as
|
|
// we will reduce the instruction count.
|
|
ReducedInstCount |= (isa<Constant>(X) && isa<Constant>(Z)) ||
|
|
(isa<Constant>(Y) && isa<Constant>(W));
|
|
if (ReducedInstCount ? (NewCost > OldCost) : (NewCost >= OldCost))
|
|
return false;
|
|
|
|
Value *Shuf0 = Builder.CreateShuffleVector(X, Z, NewMask0);
|
|
Value *Shuf1 = Builder.CreateShuffleVector(Y, W, NewMask1);
|
|
Value *NewBO = PredLHS == CmpInst::BAD_ICMP_PREDICATE
|
|
? Builder.CreateBinOp(
|
|
cast<BinaryOperator>(LHS)->getOpcode(), Shuf0, Shuf1)
|
|
: Builder.CreateCmp(PredLHS, Shuf0, Shuf1);
|
|
|
|
// Intersect flags from the old binops.
|
|
if (auto *NewInst = dyn_cast<Instruction>(NewBO)) {
|
|
NewInst->copyIRFlags(LHS);
|
|
NewInst->andIRFlags(RHS);
|
|
}
|
|
|
|
Worklist.pushValue(Shuf0);
|
|
Worklist.pushValue(Shuf1);
|
|
replaceValue(I, *NewBO);
|
|
return true;
|
|
}
|
|
|
|
/// Try to convert "shuffle (castop), (castop)" with a shared castop operand
|
|
/// into "castop (shuffle)".
|
|
bool VectorCombine::foldShuffleOfCastops(Instruction &I) {
|
|
Value *V0, *V1;
|
|
ArrayRef<int> OldMask;
|
|
if (!match(&I, m_Shuffle(m_Value(V0), m_Value(V1), m_Mask(OldMask))))
|
|
return false;
|
|
|
|
auto *C0 = dyn_cast<CastInst>(V0);
|
|
auto *C1 = dyn_cast<CastInst>(V1);
|
|
if (!C0 || !C1)
|
|
return false;
|
|
|
|
Instruction::CastOps Opcode = C0->getOpcode();
|
|
if (C0->getSrcTy() != C1->getSrcTy())
|
|
return false;
|
|
|
|
// Handle shuffle(zext_nneg(x), sext(y)) -> sext(shuffle(x,y)) folds.
|
|
if (Opcode != C1->getOpcode()) {
|
|
if (match(C0, m_SExtLike(m_Value())) && match(C1, m_SExtLike(m_Value())))
|
|
Opcode = Instruction::SExt;
|
|
else
|
|
return false;
|
|
}
|
|
|
|
auto *ShuffleDstTy = dyn_cast<FixedVectorType>(I.getType());
|
|
auto *CastDstTy = dyn_cast<FixedVectorType>(C0->getDestTy());
|
|
auto *CastSrcTy = dyn_cast<FixedVectorType>(C0->getSrcTy());
|
|
if (!ShuffleDstTy || !CastDstTy || !CastSrcTy)
|
|
return false;
|
|
|
|
unsigned NumSrcElts = CastSrcTy->getNumElements();
|
|
unsigned NumDstElts = CastDstTy->getNumElements();
|
|
assert((NumDstElts == NumSrcElts || Opcode == Instruction::BitCast) &&
|
|
"Only bitcasts expected to alter src/dst element counts");
|
|
|
|
// Check for bitcasting of unscalable vector types.
|
|
// e.g. <32 x i40> -> <40 x i32>
|
|
if (NumDstElts != NumSrcElts && (NumSrcElts % NumDstElts) != 0 &&
|
|
(NumDstElts % NumSrcElts) != 0)
|
|
return false;
|
|
|
|
SmallVector<int, 16> NewMask;
|
|
if (NumSrcElts >= NumDstElts) {
|
|
// The bitcast is from wide to narrow/equal elements. The shuffle mask can
|
|
// always be expanded to the equivalent form choosing narrower elements.
|
|
assert(NumSrcElts % NumDstElts == 0 && "Unexpected shuffle mask");
|
|
unsigned ScaleFactor = NumSrcElts / NumDstElts;
|
|
narrowShuffleMaskElts(ScaleFactor, OldMask, NewMask);
|
|
} else {
|
|
// The bitcast is from narrow elements to wide elements. The shuffle mask
|
|
// must choose consecutive elements to allow casting first.
|
|
assert(NumDstElts % NumSrcElts == 0 && "Unexpected shuffle mask");
|
|
unsigned ScaleFactor = NumDstElts / NumSrcElts;
|
|
if (!widenShuffleMaskElts(ScaleFactor, OldMask, NewMask))
|
|
return false;
|
|
}
|
|
|
|
auto *NewShuffleDstTy =
|
|
FixedVectorType::get(CastSrcTy->getScalarType(), NewMask.size());
|
|
|
|
// Try to replace a castop with a shuffle if the shuffle is not costly.
|
|
InstructionCost CostC0 =
|
|
TTI.getCastInstrCost(C0->getOpcode(), CastDstTy, CastSrcTy,
|
|
TTI::CastContextHint::None, CostKind);
|
|
InstructionCost CostC1 =
|
|
TTI.getCastInstrCost(C1->getOpcode(), CastDstTy, CastSrcTy,
|
|
TTI::CastContextHint::None, CostKind);
|
|
InstructionCost OldCost = CostC0 + CostC1;
|
|
OldCost +=
|
|
TTI.getShuffleCost(TargetTransformInfo::SK_PermuteTwoSrc, CastDstTy,
|
|
OldMask, CostKind, 0, nullptr, {}, &I);
|
|
|
|
InstructionCost NewCost = TTI.getShuffleCost(
|
|
TargetTransformInfo::SK_PermuteTwoSrc, CastSrcTy, NewMask, CostKind);
|
|
NewCost += TTI.getCastInstrCost(Opcode, ShuffleDstTy, NewShuffleDstTy,
|
|
TTI::CastContextHint::None, CostKind);
|
|
if (!C0->hasOneUse())
|
|
NewCost += CostC0;
|
|
if (!C1->hasOneUse())
|
|
NewCost += CostC1;
|
|
|
|
LLVM_DEBUG(dbgs() << "Found a shuffle feeding two casts: " << I
|
|
<< "\n OldCost: " << OldCost << " vs NewCost: " << NewCost
|
|
<< "\n");
|
|
if (NewCost > OldCost)
|
|
return false;
|
|
|
|
Value *Shuf = Builder.CreateShuffleVector(C0->getOperand(0),
|
|
C1->getOperand(0), NewMask);
|
|
Value *Cast = Builder.CreateCast(Opcode, Shuf, ShuffleDstTy);
|
|
|
|
// Intersect flags from the old casts.
|
|
if (auto *NewInst = dyn_cast<Instruction>(Cast)) {
|
|
NewInst->copyIRFlags(C0);
|
|
NewInst->andIRFlags(C1);
|
|
}
|
|
|
|
Worklist.pushValue(Shuf);
|
|
replaceValue(I, *Cast);
|
|
return true;
|
|
}
|
|
|
|
/// Try to convert any of:
|
|
/// "shuffle (shuffle x, y), (shuffle y, x)"
|
|
/// "shuffle (shuffle x, undef), (shuffle y, undef)"
|
|
/// "shuffle (shuffle x, undef), y"
|
|
/// "shuffle x, (shuffle y, undef)"
|
|
/// into "shuffle x, y".
|
|
bool VectorCombine::foldShuffleOfShuffles(Instruction &I) {
|
|
ArrayRef<int> OuterMask;
|
|
Value *OuterV0, *OuterV1;
|
|
if (!match(&I,
|
|
m_Shuffle(m_Value(OuterV0), m_Value(OuterV1), m_Mask(OuterMask))))
|
|
return false;
|
|
|
|
ArrayRef<int> InnerMask0, InnerMask1;
|
|
Value *X0, *X1, *Y0, *Y1;
|
|
bool Match0 =
|
|
match(OuterV0, m_Shuffle(m_Value(X0), m_Value(Y0), m_Mask(InnerMask0)));
|
|
bool Match1 =
|
|
match(OuterV1, m_Shuffle(m_Value(X1), m_Value(Y1), m_Mask(InnerMask1)));
|
|
if (!Match0 && !Match1)
|
|
return false;
|
|
|
|
X0 = Match0 ? X0 : OuterV0;
|
|
Y0 = Match0 ? Y0 : OuterV0;
|
|
X1 = Match1 ? X1 : OuterV1;
|
|
Y1 = Match1 ? Y1 : OuterV1;
|
|
auto *ShuffleDstTy = dyn_cast<FixedVectorType>(I.getType());
|
|
auto *ShuffleSrcTy = dyn_cast<FixedVectorType>(X0->getType());
|
|
auto *ShuffleImmTy = dyn_cast<FixedVectorType>(OuterV0->getType());
|
|
if (!ShuffleDstTy || !ShuffleSrcTy || !ShuffleImmTy ||
|
|
X0->getType() != X1->getType())
|
|
return false;
|
|
|
|
unsigned NumSrcElts = ShuffleSrcTy->getNumElements();
|
|
unsigned NumImmElts = ShuffleImmTy->getNumElements();
|
|
|
|
// Attempt to merge shuffles, matching upto 2 source operands.
|
|
// Replace index to a poison arg with PoisonMaskElem.
|
|
// Bail if either inner masks reference an undef arg.
|
|
SmallVector<int, 16> NewMask(OuterMask);
|
|
Value *NewX = nullptr, *NewY = nullptr;
|
|
for (int &M : NewMask) {
|
|
Value *Src = nullptr;
|
|
if (0 <= M && M < (int)NumImmElts) {
|
|
Src = OuterV0;
|
|
if (Match0) {
|
|
M = InnerMask0[M];
|
|
Src = M >= (int)NumSrcElts ? Y0 : X0;
|
|
M = M >= (int)NumSrcElts ? (M - NumSrcElts) : M;
|
|
}
|
|
} else if (M >= (int)NumImmElts) {
|
|
Src = OuterV1;
|
|
M -= NumImmElts;
|
|
if (Match1) {
|
|
M = InnerMask1[M];
|
|
Src = M >= (int)NumSrcElts ? Y1 : X1;
|
|
M = M >= (int)NumSrcElts ? (M - NumSrcElts) : M;
|
|
}
|
|
}
|
|
if (Src && M != PoisonMaskElem) {
|
|
assert(0 <= M && M < (int)NumSrcElts && "Unexpected shuffle mask index");
|
|
if (isa<UndefValue>(Src)) {
|
|
// We've referenced an undef element - if its poison, update the shuffle
|
|
// mask, else bail.
|
|
if (!isa<PoisonValue>(Src))
|
|
return false;
|
|
M = PoisonMaskElem;
|
|
continue;
|
|
}
|
|
if (!NewX || NewX == Src) {
|
|
NewX = Src;
|
|
continue;
|
|
}
|
|
if (!NewY || NewY == Src) {
|
|
M += NumSrcElts;
|
|
NewY = Src;
|
|
continue;
|
|
}
|
|
return false;
|
|
}
|
|
}
|
|
|
|
if (!NewX)
|
|
return PoisonValue::get(ShuffleDstTy);
|
|
if (!NewY)
|
|
NewY = PoisonValue::get(ShuffleSrcTy);
|
|
|
|
// Have we folded to an Identity shuffle?
|
|
if (ShuffleVectorInst::isIdentityMask(NewMask, NumSrcElts)) {
|
|
replaceValue(I, *NewX);
|
|
return true;
|
|
}
|
|
|
|
// Try to merge the shuffles if the new shuffle is not costly.
|
|
InstructionCost InnerCost0 = 0;
|
|
if (Match0)
|
|
InnerCost0 = TTI.getInstructionCost(cast<Instruction>(OuterV0), CostKind);
|
|
|
|
InstructionCost InnerCost1 = 0;
|
|
if (Match1)
|
|
InnerCost1 = TTI.getInstructionCost(cast<Instruction>(OuterV1), CostKind);
|
|
|
|
InstructionCost OuterCost = TTI.getInstructionCost(&I, CostKind);
|
|
|
|
InstructionCost OldCost = InnerCost0 + InnerCost1 + OuterCost;
|
|
|
|
bool IsUnary = all_of(NewMask, [&](int M) { return M < (int)NumSrcElts; });
|
|
TargetTransformInfo::ShuffleKind SK =
|
|
IsUnary ? TargetTransformInfo::SK_PermuteSingleSrc
|
|
: TargetTransformInfo::SK_PermuteTwoSrc;
|
|
InstructionCost NewCost = TTI.getShuffleCost(
|
|
SK, ShuffleSrcTy, NewMask, CostKind, 0, nullptr, {NewX, NewY});
|
|
if (!OuterV0->hasOneUse())
|
|
NewCost += InnerCost0;
|
|
if (!OuterV1->hasOneUse())
|
|
NewCost += InnerCost1;
|
|
|
|
LLVM_DEBUG(dbgs() << "Found a shuffle feeding two shuffles: " << I
|
|
<< "\n OldCost: " << OldCost << " vs NewCost: " << NewCost
|
|
<< "\n");
|
|
if (NewCost > OldCost)
|
|
return false;
|
|
|
|
Value *Shuf = Builder.CreateShuffleVector(NewX, NewY, NewMask);
|
|
replaceValue(I, *Shuf);
|
|
return true;
|
|
}
|
|
|
|
/// Try to convert
|
|
/// "shuffle (intrinsic), (intrinsic)" into "intrinsic (shuffle), (shuffle)".
|
|
bool VectorCombine::foldShuffleOfIntrinsics(Instruction &I) {
|
|
Value *V0, *V1;
|
|
ArrayRef<int> OldMask;
|
|
if (!match(&I, m_Shuffle(m_OneUse(m_Value(V0)), m_OneUse(m_Value(V1)),
|
|
m_Mask(OldMask))))
|
|
return false;
|
|
|
|
auto *II0 = dyn_cast<IntrinsicInst>(V0);
|
|
auto *II1 = dyn_cast<IntrinsicInst>(V1);
|
|
if (!II0 || !II1)
|
|
return false;
|
|
|
|
Intrinsic::ID IID = II0->getIntrinsicID();
|
|
if (IID != II1->getIntrinsicID())
|
|
return false;
|
|
|
|
auto *ShuffleDstTy = dyn_cast<FixedVectorType>(I.getType());
|
|
auto *II0Ty = dyn_cast<FixedVectorType>(II0->getType());
|
|
if (!ShuffleDstTy || !II0Ty)
|
|
return false;
|
|
|
|
if (!isTriviallyVectorizable(IID))
|
|
return false;
|
|
|
|
for (unsigned I = 0, E = II0->arg_size(); I != E; ++I)
|
|
if (isVectorIntrinsicWithScalarOpAtArg(IID, I, &TTI) &&
|
|
II0->getArgOperand(I) != II1->getArgOperand(I))
|
|
return false;
|
|
|
|
InstructionCost OldCost =
|
|
TTI.getIntrinsicInstrCost(IntrinsicCostAttributes(IID, *II0), CostKind) +
|
|
TTI.getIntrinsicInstrCost(IntrinsicCostAttributes(IID, *II1), CostKind) +
|
|
TTI.getShuffleCost(TargetTransformInfo::SK_PermuteTwoSrc, II0Ty, OldMask,
|
|
CostKind, 0, nullptr, {II0, II1}, &I);
|
|
|
|
SmallVector<Type *> NewArgsTy;
|
|
InstructionCost NewCost = 0;
|
|
for (unsigned I = 0, E = II0->arg_size(); I != E; ++I)
|
|
if (isVectorIntrinsicWithScalarOpAtArg(IID, I, &TTI)) {
|
|
NewArgsTy.push_back(II0->getArgOperand(I)->getType());
|
|
} else {
|
|
auto *VecTy = cast<FixedVectorType>(II0->getArgOperand(I)->getType());
|
|
NewArgsTy.push_back(FixedVectorType::get(VecTy->getElementType(),
|
|
VecTy->getNumElements() * 2));
|
|
NewCost += TTI.getShuffleCost(TargetTransformInfo::SK_PermuteTwoSrc,
|
|
VecTy, OldMask, CostKind);
|
|
}
|
|
IntrinsicCostAttributes NewAttr(IID, ShuffleDstTy, NewArgsTy);
|
|
NewCost += TTI.getIntrinsicInstrCost(NewAttr, CostKind);
|
|
|
|
LLVM_DEBUG(dbgs() << "Found a shuffle feeding two intrinsics: " << I
|
|
<< "\n OldCost: " << OldCost << " vs NewCost: " << NewCost
|
|
<< "\n");
|
|
|
|
if (NewCost > OldCost)
|
|
return false;
|
|
|
|
SmallVector<Value *> NewArgs;
|
|
for (unsigned I = 0, E = II0->arg_size(); I != E; ++I)
|
|
if (isVectorIntrinsicWithScalarOpAtArg(IID, I, &TTI)) {
|
|
NewArgs.push_back(II0->getArgOperand(I));
|
|
} else {
|
|
Value *Shuf = Builder.CreateShuffleVector(II0->getArgOperand(I),
|
|
II1->getArgOperand(I), OldMask);
|
|
NewArgs.push_back(Shuf);
|
|
Worklist.pushValue(Shuf);
|
|
}
|
|
Value *NewIntrinsic = Builder.CreateIntrinsic(ShuffleDstTy, IID, NewArgs);
|
|
|
|
// Intersect flags from the old intrinsics.
|
|
if (auto *NewInst = dyn_cast<Instruction>(NewIntrinsic)) {
|
|
NewInst->copyIRFlags(II0);
|
|
NewInst->andIRFlags(II1);
|
|
}
|
|
|
|
replaceValue(I, *NewIntrinsic);
|
|
return true;
|
|
}
|
|
|
|
using InstLane = std::pair<Use *, int>;
|
|
|
|
static InstLane lookThroughShuffles(Use *U, int Lane) {
|
|
while (auto *SV = dyn_cast<ShuffleVectorInst>(U->get())) {
|
|
unsigned NumElts =
|
|
cast<FixedVectorType>(SV->getOperand(0)->getType())->getNumElements();
|
|
int M = SV->getMaskValue(Lane);
|
|
if (M < 0)
|
|
return {nullptr, PoisonMaskElem};
|
|
if (static_cast<unsigned>(M) < NumElts) {
|
|
U = &SV->getOperandUse(0);
|
|
Lane = M;
|
|
} else {
|
|
U = &SV->getOperandUse(1);
|
|
Lane = M - NumElts;
|
|
}
|
|
}
|
|
return InstLane{U, Lane};
|
|
}
|
|
|
|
static SmallVector<InstLane>
|
|
generateInstLaneVectorFromOperand(ArrayRef<InstLane> Item, int Op) {
|
|
SmallVector<InstLane> NItem;
|
|
for (InstLane IL : Item) {
|
|
auto [U, Lane] = IL;
|
|
InstLane OpLane =
|
|
U ? lookThroughShuffles(&cast<Instruction>(U->get())->getOperandUse(Op),
|
|
Lane)
|
|
: InstLane{nullptr, PoisonMaskElem};
|
|
NItem.emplace_back(OpLane);
|
|
}
|
|
return NItem;
|
|
}
|
|
|
|
/// Detect concat of multiple values into a vector
|
|
static bool isFreeConcat(ArrayRef<InstLane> Item, TTI::TargetCostKind CostKind,
|
|
const TargetTransformInfo &TTI) {
|
|
auto *Ty = cast<FixedVectorType>(Item.front().first->get()->getType());
|
|
unsigned NumElts = Ty->getNumElements();
|
|
if (Item.size() == NumElts || NumElts == 1 || Item.size() % NumElts != 0)
|
|
return false;
|
|
|
|
// Check that the concat is free, usually meaning that the type will be split
|
|
// during legalization.
|
|
SmallVector<int, 16> ConcatMask(NumElts * 2);
|
|
std::iota(ConcatMask.begin(), ConcatMask.end(), 0);
|
|
if (TTI.getShuffleCost(TTI::SK_PermuteTwoSrc, Ty, ConcatMask, CostKind) != 0)
|
|
return false;
|
|
|
|
unsigned NumSlices = Item.size() / NumElts;
|
|
// Currently we generate a tree of shuffles for the concats, which limits us
|
|
// to a power2.
|
|
if (!isPowerOf2_32(NumSlices))
|
|
return false;
|
|
for (unsigned Slice = 0; Slice < NumSlices; ++Slice) {
|
|
Use *SliceV = Item[Slice * NumElts].first;
|
|
if (!SliceV || SliceV->get()->getType() != Ty)
|
|
return false;
|
|
for (unsigned Elt = 0; Elt < NumElts; ++Elt) {
|
|
auto [V, Lane] = Item[Slice * NumElts + Elt];
|
|
if (Lane != static_cast<int>(Elt) || SliceV->get() != V->get())
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static Value *generateNewInstTree(ArrayRef<InstLane> Item, FixedVectorType *Ty,
|
|
const SmallPtrSet<Use *, 4> &IdentityLeafs,
|
|
const SmallPtrSet<Use *, 4> &SplatLeafs,
|
|
const SmallPtrSet<Use *, 4> &ConcatLeafs,
|
|
IRBuilder<> &Builder,
|
|
const TargetTransformInfo *TTI) {
|
|
auto [FrontU, FrontLane] = Item.front();
|
|
|
|
if (IdentityLeafs.contains(FrontU)) {
|
|
return FrontU->get();
|
|
}
|
|
if (SplatLeafs.contains(FrontU)) {
|
|
SmallVector<int, 16> Mask(Ty->getNumElements(), FrontLane);
|
|
return Builder.CreateShuffleVector(FrontU->get(), Mask);
|
|
}
|
|
if (ConcatLeafs.contains(FrontU)) {
|
|
unsigned NumElts =
|
|
cast<FixedVectorType>(FrontU->get()->getType())->getNumElements();
|
|
SmallVector<Value *> Values(Item.size() / NumElts, nullptr);
|
|
for (unsigned S = 0; S < Values.size(); ++S)
|
|
Values[S] = Item[S * NumElts].first->get();
|
|
|
|
while (Values.size() > 1) {
|
|
NumElts *= 2;
|
|
SmallVector<int, 16> Mask(NumElts, 0);
|
|
std::iota(Mask.begin(), Mask.end(), 0);
|
|
SmallVector<Value *> NewValues(Values.size() / 2, nullptr);
|
|
for (unsigned S = 0; S < NewValues.size(); ++S)
|
|
NewValues[S] =
|
|
Builder.CreateShuffleVector(Values[S * 2], Values[S * 2 + 1], Mask);
|
|
Values = NewValues;
|
|
}
|
|
return Values[0];
|
|
}
|
|
|
|
auto *I = cast<Instruction>(FrontU->get());
|
|
auto *II = dyn_cast<IntrinsicInst>(I);
|
|
unsigned NumOps = I->getNumOperands() - (II ? 1 : 0);
|
|
SmallVector<Value *> Ops(NumOps);
|
|
for (unsigned Idx = 0; Idx < NumOps; Idx++) {
|
|
if (II &&
|
|
isVectorIntrinsicWithScalarOpAtArg(II->getIntrinsicID(), Idx, TTI)) {
|
|
Ops[Idx] = II->getOperand(Idx);
|
|
continue;
|
|
}
|
|
Ops[Idx] = generateNewInstTree(generateInstLaneVectorFromOperand(Item, Idx),
|
|
Ty, IdentityLeafs, SplatLeafs, ConcatLeafs,
|
|
Builder, TTI);
|
|
}
|
|
|
|
SmallVector<Value *, 8> ValueList;
|
|
for (const auto &Lane : Item)
|
|
if (Lane.first)
|
|
ValueList.push_back(Lane.first->get());
|
|
|
|
Type *DstTy =
|
|
FixedVectorType::get(I->getType()->getScalarType(), Ty->getNumElements());
|
|
if (auto *BI = dyn_cast<BinaryOperator>(I)) {
|
|
auto *Value = Builder.CreateBinOp((Instruction::BinaryOps)BI->getOpcode(),
|
|
Ops[0], Ops[1]);
|
|
propagateIRFlags(Value, ValueList);
|
|
return Value;
|
|
}
|
|
if (auto *CI = dyn_cast<CmpInst>(I)) {
|
|
auto *Value = Builder.CreateCmp(CI->getPredicate(), Ops[0], Ops[1]);
|
|
propagateIRFlags(Value, ValueList);
|
|
return Value;
|
|
}
|
|
if (auto *SI = dyn_cast<SelectInst>(I)) {
|
|
auto *Value = Builder.CreateSelect(Ops[0], Ops[1], Ops[2], "", SI);
|
|
propagateIRFlags(Value, ValueList);
|
|
return Value;
|
|
}
|
|
if (auto *CI = dyn_cast<CastInst>(I)) {
|
|
auto *Value = Builder.CreateCast((Instruction::CastOps)CI->getOpcode(),
|
|
Ops[0], DstTy);
|
|
propagateIRFlags(Value, ValueList);
|
|
return Value;
|
|
}
|
|
if (II) {
|
|
auto *Value = Builder.CreateIntrinsic(DstTy, II->getIntrinsicID(), Ops);
|
|
propagateIRFlags(Value, ValueList);
|
|
return Value;
|
|
}
|
|
assert(isa<UnaryInstruction>(I) && "Unexpected instruction type in Generate");
|
|
auto *Value =
|
|
Builder.CreateUnOp((Instruction::UnaryOps)I->getOpcode(), Ops[0]);
|
|
propagateIRFlags(Value, ValueList);
|
|
return Value;
|
|
}
|
|
|
|
// Starting from a shuffle, look up through operands tracking the shuffled index
|
|
// of each lane. If we can simplify away the shuffles to identities then
|
|
// do so.
|
|
bool VectorCombine::foldShuffleToIdentity(Instruction &I) {
|
|
auto *Ty = dyn_cast<FixedVectorType>(I.getType());
|
|
if (!Ty || I.use_empty())
|
|
return false;
|
|
|
|
SmallVector<InstLane> Start(Ty->getNumElements());
|
|
for (unsigned M = 0, E = Ty->getNumElements(); M < E; ++M)
|
|
Start[M] = lookThroughShuffles(&*I.use_begin(), M);
|
|
|
|
SmallVector<SmallVector<InstLane>> Worklist;
|
|
Worklist.push_back(Start);
|
|
SmallPtrSet<Use *, 4> IdentityLeafs, SplatLeafs, ConcatLeafs;
|
|
unsigned NumVisited = 0;
|
|
|
|
while (!Worklist.empty()) {
|
|
if (++NumVisited > MaxInstrsToScan)
|
|
return false;
|
|
|
|
SmallVector<InstLane> Item = Worklist.pop_back_val();
|
|
auto [FrontU, FrontLane] = Item.front();
|
|
|
|
// If we found an undef first lane then bail out to keep things simple.
|
|
if (!FrontU)
|
|
return false;
|
|
|
|
// Helper to peek through bitcasts to the same value.
|
|
auto IsEquiv = [&](Value *X, Value *Y) {
|
|
return X->getType() == Y->getType() &&
|
|
peekThroughBitcasts(X) == peekThroughBitcasts(Y);
|
|
};
|
|
|
|
// Look for an identity value.
|
|
if (FrontLane == 0 &&
|
|
cast<FixedVectorType>(FrontU->get()->getType())->getNumElements() ==
|
|
Ty->getNumElements() &&
|
|
all_of(drop_begin(enumerate(Item)), [IsEquiv, Item](const auto &E) {
|
|
Value *FrontV = Item.front().first->get();
|
|
return !E.value().first || (IsEquiv(E.value().first->get(), FrontV) &&
|
|
E.value().second == (int)E.index());
|
|
})) {
|
|
IdentityLeafs.insert(FrontU);
|
|
continue;
|
|
}
|
|
// Look for constants, for the moment only supporting constant splats.
|
|
if (auto *C = dyn_cast<Constant>(FrontU);
|
|
C && C->getSplatValue() &&
|
|
all_of(drop_begin(Item), [Item](InstLane &IL) {
|
|
Value *FrontV = Item.front().first->get();
|
|
Use *U = IL.first;
|
|
return !U || (isa<Constant>(U->get()) &&
|
|
cast<Constant>(U->get())->getSplatValue() ==
|
|
cast<Constant>(FrontV)->getSplatValue());
|
|
})) {
|
|
SplatLeafs.insert(FrontU);
|
|
continue;
|
|
}
|
|
// Look for a splat value.
|
|
if (all_of(drop_begin(Item), [Item](InstLane &IL) {
|
|
auto [FrontU, FrontLane] = Item.front();
|
|
auto [U, Lane] = IL;
|
|
return !U || (U->get() == FrontU->get() && Lane == FrontLane);
|
|
})) {
|
|
SplatLeafs.insert(FrontU);
|
|
continue;
|
|
}
|
|
|
|
// We need each element to be the same type of value, and check that each
|
|
// element has a single use.
|
|
auto CheckLaneIsEquivalentToFirst = [Item](InstLane IL) {
|
|
Value *FrontV = Item.front().first->get();
|
|
if (!IL.first)
|
|
return true;
|
|
Value *V = IL.first->get();
|
|
if (auto *I = dyn_cast<Instruction>(V); I && !I->hasOneUse())
|
|
return false;
|
|
if (V->getValueID() != FrontV->getValueID())
|
|
return false;
|
|
if (auto *CI = dyn_cast<CmpInst>(V))
|
|
if (CI->getPredicate() != cast<CmpInst>(FrontV)->getPredicate())
|
|
return false;
|
|
if (auto *CI = dyn_cast<CastInst>(V))
|
|
if (CI->getSrcTy()->getScalarType() !=
|
|
cast<CastInst>(FrontV)->getSrcTy()->getScalarType())
|
|
return false;
|
|
if (auto *SI = dyn_cast<SelectInst>(V))
|
|
if (!isa<VectorType>(SI->getOperand(0)->getType()) ||
|
|
SI->getOperand(0)->getType() !=
|
|
cast<SelectInst>(FrontV)->getOperand(0)->getType())
|
|
return false;
|
|
if (isa<CallInst>(V) && !isa<IntrinsicInst>(V))
|
|
return false;
|
|
auto *II = dyn_cast<IntrinsicInst>(V);
|
|
return !II || (isa<IntrinsicInst>(FrontV) &&
|
|
II->getIntrinsicID() ==
|
|
cast<IntrinsicInst>(FrontV)->getIntrinsicID() &&
|
|
!II->hasOperandBundles());
|
|
};
|
|
if (all_of(drop_begin(Item), CheckLaneIsEquivalentToFirst)) {
|
|
// Check the operator is one that we support.
|
|
if (isa<BinaryOperator, CmpInst>(FrontU)) {
|
|
// We exclude div/rem in case they hit UB from poison lanes.
|
|
if (auto *BO = dyn_cast<BinaryOperator>(FrontU);
|
|
BO && BO->isIntDivRem())
|
|
return false;
|
|
Worklist.push_back(generateInstLaneVectorFromOperand(Item, 0));
|
|
Worklist.push_back(generateInstLaneVectorFromOperand(Item, 1));
|
|
continue;
|
|
} else if (isa<UnaryOperator, TruncInst, ZExtInst, SExtInst, FPToSIInst,
|
|
FPToUIInst, SIToFPInst, UIToFPInst>(FrontU)) {
|
|
Worklist.push_back(generateInstLaneVectorFromOperand(Item, 0));
|
|
continue;
|
|
} else if (auto *BitCast = dyn_cast<BitCastInst>(FrontU)) {
|
|
// TODO: Handle vector widening/narrowing bitcasts.
|
|
auto *DstTy = dyn_cast<FixedVectorType>(BitCast->getDestTy());
|
|
auto *SrcTy = dyn_cast<FixedVectorType>(BitCast->getSrcTy());
|
|
if (DstTy && SrcTy &&
|
|
SrcTy->getNumElements() == DstTy->getNumElements()) {
|
|
Worklist.push_back(generateInstLaneVectorFromOperand(Item, 0));
|
|
continue;
|
|
}
|
|
} else if (isa<SelectInst>(FrontU)) {
|
|
Worklist.push_back(generateInstLaneVectorFromOperand(Item, 0));
|
|
Worklist.push_back(generateInstLaneVectorFromOperand(Item, 1));
|
|
Worklist.push_back(generateInstLaneVectorFromOperand(Item, 2));
|
|
continue;
|
|
} else if (auto *II = dyn_cast<IntrinsicInst>(FrontU);
|
|
II && isTriviallyVectorizable(II->getIntrinsicID()) &&
|
|
!II->hasOperandBundles()) {
|
|
for (unsigned Op = 0, E = II->getNumOperands() - 1; Op < E; Op++) {
|
|
if (isVectorIntrinsicWithScalarOpAtArg(II->getIntrinsicID(), Op,
|
|
&TTI)) {
|
|
if (!all_of(drop_begin(Item), [Item, Op](InstLane &IL) {
|
|
Value *FrontV = Item.front().first->get();
|
|
Use *U = IL.first;
|
|
return !U || (cast<Instruction>(U->get())->getOperand(Op) ==
|
|
cast<Instruction>(FrontV)->getOperand(Op));
|
|
}))
|
|
return false;
|
|
continue;
|
|
}
|
|
Worklist.push_back(generateInstLaneVectorFromOperand(Item, Op));
|
|
}
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if (isFreeConcat(Item, CostKind, TTI)) {
|
|
ConcatLeafs.insert(FrontU);
|
|
continue;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
if (NumVisited <= 1)
|
|
return false;
|
|
|
|
LLVM_DEBUG(dbgs() << "Found a superfluous identity shuffle: " << I << "\n");
|
|
|
|
// If we got this far, we know the shuffles are superfluous and can be
|
|
// removed. Scan through again and generate the new tree of instructions.
|
|
Builder.SetInsertPoint(&I);
|
|
Value *V = generateNewInstTree(Start, Ty, IdentityLeafs, SplatLeafs,
|
|
ConcatLeafs, Builder, &TTI);
|
|
replaceValue(I, *V);
|
|
return true;
|
|
}
|
|
|
|
/// Given a commutative reduction, the order of the input lanes does not alter
|
|
/// the results. We can use this to remove certain shuffles feeding the
|
|
/// reduction, removing the need to shuffle at all.
|
|
bool VectorCombine::foldShuffleFromReductions(Instruction &I) {
|
|
auto *II = dyn_cast<IntrinsicInst>(&I);
|
|
if (!II)
|
|
return false;
|
|
switch (II->getIntrinsicID()) {
|
|
case Intrinsic::vector_reduce_add:
|
|
case Intrinsic::vector_reduce_mul:
|
|
case Intrinsic::vector_reduce_and:
|
|
case Intrinsic::vector_reduce_or:
|
|
case Intrinsic::vector_reduce_xor:
|
|
case Intrinsic::vector_reduce_smin:
|
|
case Intrinsic::vector_reduce_smax:
|
|
case Intrinsic::vector_reduce_umin:
|
|
case Intrinsic::vector_reduce_umax:
|
|
break;
|
|
default:
|
|
return false;
|
|
}
|
|
|
|
// Find all the inputs when looking through operations that do not alter the
|
|
// lane order (binops, for example). Currently we look for a single shuffle,
|
|
// and can ignore splat values.
|
|
std::queue<Value *> Worklist;
|
|
SmallPtrSet<Value *, 4> Visited;
|
|
ShuffleVectorInst *Shuffle = nullptr;
|
|
if (auto *Op = dyn_cast<Instruction>(I.getOperand(0)))
|
|
Worklist.push(Op);
|
|
|
|
while (!Worklist.empty()) {
|
|
Value *CV = Worklist.front();
|
|
Worklist.pop();
|
|
if (Visited.contains(CV))
|
|
continue;
|
|
|
|
// Splats don't change the order, so can be safely ignored.
|
|
if (isSplatValue(CV))
|
|
continue;
|
|
|
|
Visited.insert(CV);
|
|
|
|
if (auto *CI = dyn_cast<Instruction>(CV)) {
|
|
if (CI->isBinaryOp()) {
|
|
for (auto *Op : CI->operand_values())
|
|
Worklist.push(Op);
|
|
continue;
|
|
} else if (auto *SV = dyn_cast<ShuffleVectorInst>(CI)) {
|
|
if (Shuffle && Shuffle != SV)
|
|
return false;
|
|
Shuffle = SV;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Anything else is currently an unknown node.
|
|
return false;
|
|
}
|
|
|
|
if (!Shuffle)
|
|
return false;
|
|
|
|
// Check all uses of the binary ops and shuffles are also included in the
|
|
// lane-invariant operations (Visited should be the list of lanewise
|
|
// instructions, including the shuffle that we found).
|
|
for (auto *V : Visited)
|
|
for (auto *U : V->users())
|
|
if (!Visited.contains(U) && U != &I)
|
|
return false;
|
|
|
|
FixedVectorType *VecType =
|
|
dyn_cast<FixedVectorType>(II->getOperand(0)->getType());
|
|
if (!VecType)
|
|
return false;
|
|
FixedVectorType *ShuffleInputType =
|
|
dyn_cast<FixedVectorType>(Shuffle->getOperand(0)->getType());
|
|
if (!ShuffleInputType)
|
|
return false;
|
|
unsigned NumInputElts = ShuffleInputType->getNumElements();
|
|
|
|
// Find the mask from sorting the lanes into order. This is most likely to
|
|
// become a identity or concat mask. Undef elements are pushed to the end.
|
|
SmallVector<int> ConcatMask;
|
|
Shuffle->getShuffleMask(ConcatMask);
|
|
sort(ConcatMask, [](int X, int Y) { return (unsigned)X < (unsigned)Y; });
|
|
// In the case of a truncating shuffle it's possible for the mask
|
|
// to have an index greater than the size of the resulting vector.
|
|
// This requires special handling.
|
|
bool IsTruncatingShuffle = VecType->getNumElements() < NumInputElts;
|
|
bool UsesSecondVec =
|
|
any_of(ConcatMask, [&](int M) { return M >= (int)NumInputElts; });
|
|
|
|
FixedVectorType *VecTyForCost =
|
|
(UsesSecondVec && !IsTruncatingShuffle) ? VecType : ShuffleInputType;
|
|
InstructionCost OldCost = TTI.getShuffleCost(
|
|
UsesSecondVec ? TTI::SK_PermuteTwoSrc : TTI::SK_PermuteSingleSrc,
|
|
VecTyForCost, Shuffle->getShuffleMask(), CostKind);
|
|
InstructionCost NewCost = TTI.getShuffleCost(
|
|
UsesSecondVec ? TTI::SK_PermuteTwoSrc : TTI::SK_PermuteSingleSrc,
|
|
VecTyForCost, ConcatMask, CostKind);
|
|
|
|
LLVM_DEBUG(dbgs() << "Found a reduction feeding from a shuffle: " << *Shuffle
|
|
<< "\n");
|
|
LLVM_DEBUG(dbgs() << " OldCost: " << OldCost << " vs NewCost: " << NewCost
|
|
<< "\n");
|
|
if (NewCost < OldCost) {
|
|
Builder.SetInsertPoint(Shuffle);
|
|
Value *NewShuffle = Builder.CreateShuffleVector(
|
|
Shuffle->getOperand(0), Shuffle->getOperand(1), ConcatMask);
|
|
LLVM_DEBUG(dbgs() << "Created new shuffle: " << *NewShuffle << "\n");
|
|
replaceValue(*Shuffle, *NewShuffle);
|
|
}
|
|
|
|
// See if we can re-use foldSelectShuffle, getting it to reduce the size of
|
|
// the shuffle into a nicer order, as it can ignore the order of the shuffles.
|
|
return foldSelectShuffle(*Shuffle, true);
|
|
}
|
|
|
|
/// Determine if its more efficient to fold:
|
|
/// reduce(trunc(x)) -> trunc(reduce(x)).
|
|
/// reduce(sext(x)) -> sext(reduce(x)).
|
|
/// reduce(zext(x)) -> zext(reduce(x)).
|
|
bool VectorCombine::foldCastFromReductions(Instruction &I) {
|
|
auto *II = dyn_cast<IntrinsicInst>(&I);
|
|
if (!II)
|
|
return false;
|
|
|
|
bool TruncOnly = false;
|
|
Intrinsic::ID IID = II->getIntrinsicID();
|
|
switch (IID) {
|
|
case Intrinsic::vector_reduce_add:
|
|
case Intrinsic::vector_reduce_mul:
|
|
TruncOnly = true;
|
|
break;
|
|
case Intrinsic::vector_reduce_and:
|
|
case Intrinsic::vector_reduce_or:
|
|
case Intrinsic::vector_reduce_xor:
|
|
break;
|
|
default:
|
|
return false;
|
|
}
|
|
|
|
unsigned ReductionOpc = getArithmeticReductionInstruction(IID);
|
|
Value *ReductionSrc = I.getOperand(0);
|
|
|
|
Value *Src;
|
|
if (!match(ReductionSrc, m_OneUse(m_Trunc(m_Value(Src)))) &&
|
|
(TruncOnly || !match(ReductionSrc, m_OneUse(m_ZExtOrSExt(m_Value(Src))))))
|
|
return false;
|
|
|
|
auto CastOpc =
|
|
(Instruction::CastOps)cast<Instruction>(ReductionSrc)->getOpcode();
|
|
|
|
auto *SrcTy = cast<VectorType>(Src->getType());
|
|
auto *ReductionSrcTy = cast<VectorType>(ReductionSrc->getType());
|
|
Type *ResultTy = I.getType();
|
|
|
|
InstructionCost OldCost = TTI.getArithmeticReductionCost(
|
|
ReductionOpc, ReductionSrcTy, std::nullopt, CostKind);
|
|
OldCost += TTI.getCastInstrCost(CastOpc, ReductionSrcTy, SrcTy,
|
|
TTI::CastContextHint::None, CostKind,
|
|
cast<CastInst>(ReductionSrc));
|
|
InstructionCost NewCost =
|
|
TTI.getArithmeticReductionCost(ReductionOpc, SrcTy, std::nullopt,
|
|
CostKind) +
|
|
TTI.getCastInstrCost(CastOpc, ResultTy, ReductionSrcTy->getScalarType(),
|
|
TTI::CastContextHint::None, CostKind);
|
|
|
|
if (OldCost <= NewCost || !NewCost.isValid())
|
|
return false;
|
|
|
|
Value *NewReduction = Builder.CreateIntrinsic(SrcTy->getScalarType(),
|
|
II->getIntrinsicID(), {Src});
|
|
Value *NewCast = Builder.CreateCast(CastOpc, NewReduction, ResultTy);
|
|
replaceValue(I, *NewCast);
|
|
return true;
|
|
}
|
|
|
|
/// This method looks for groups of shuffles acting on binops, of the form:
|
|
/// %x = shuffle ...
|
|
/// %y = shuffle ...
|
|
/// %a = binop %x, %y
|
|
/// %b = binop %x, %y
|
|
/// shuffle %a, %b, selectmask
|
|
/// We may, especially if the shuffle is wider than legal, be able to convert
|
|
/// the shuffle to a form where only parts of a and b need to be computed. On
|
|
/// architectures with no obvious "select" shuffle, this can reduce the total
|
|
/// number of operations if the target reports them as cheaper.
|
|
bool VectorCombine::foldSelectShuffle(Instruction &I, bool FromReduction) {
|
|
auto *SVI = cast<ShuffleVectorInst>(&I);
|
|
auto *VT = cast<FixedVectorType>(I.getType());
|
|
auto *Op0 = dyn_cast<Instruction>(SVI->getOperand(0));
|
|
auto *Op1 = dyn_cast<Instruction>(SVI->getOperand(1));
|
|
if (!Op0 || !Op1 || Op0 == Op1 || !Op0->isBinaryOp() || !Op1->isBinaryOp() ||
|
|
VT != Op0->getType())
|
|
return false;
|
|
|
|
auto *SVI0A = dyn_cast<Instruction>(Op0->getOperand(0));
|
|
auto *SVI0B = dyn_cast<Instruction>(Op0->getOperand(1));
|
|
auto *SVI1A = dyn_cast<Instruction>(Op1->getOperand(0));
|
|
auto *SVI1B = dyn_cast<Instruction>(Op1->getOperand(1));
|
|
SmallPtrSet<Instruction *, 4> InputShuffles({SVI0A, SVI0B, SVI1A, SVI1B});
|
|
auto checkSVNonOpUses = [&](Instruction *I) {
|
|
if (!I || I->getOperand(0)->getType() != VT)
|
|
return true;
|
|
return any_of(I->users(), [&](User *U) {
|
|
return U != Op0 && U != Op1 &&
|
|
!(isa<ShuffleVectorInst>(U) &&
|
|
(InputShuffles.contains(cast<Instruction>(U)) ||
|
|
isInstructionTriviallyDead(cast<Instruction>(U))));
|
|
});
|
|
};
|
|
if (checkSVNonOpUses(SVI0A) || checkSVNonOpUses(SVI0B) ||
|
|
checkSVNonOpUses(SVI1A) || checkSVNonOpUses(SVI1B))
|
|
return false;
|
|
|
|
// Collect all the uses that are shuffles that we can transform together. We
|
|
// may not have a single shuffle, but a group that can all be transformed
|
|
// together profitably.
|
|
SmallVector<ShuffleVectorInst *> Shuffles;
|
|
auto collectShuffles = [&](Instruction *I) {
|
|
for (auto *U : I->users()) {
|
|
auto *SV = dyn_cast<ShuffleVectorInst>(U);
|
|
if (!SV || SV->getType() != VT)
|
|
return false;
|
|
if ((SV->getOperand(0) != Op0 && SV->getOperand(0) != Op1) ||
|
|
(SV->getOperand(1) != Op0 && SV->getOperand(1) != Op1))
|
|
return false;
|
|
if (!llvm::is_contained(Shuffles, SV))
|
|
Shuffles.push_back(SV);
|
|
}
|
|
return true;
|
|
};
|
|
if (!collectShuffles(Op0) || !collectShuffles(Op1))
|
|
return false;
|
|
// From a reduction, we need to be processing a single shuffle, otherwise the
|
|
// other uses will not be lane-invariant.
|
|
if (FromReduction && Shuffles.size() > 1)
|
|
return false;
|
|
|
|
// Add any shuffle uses for the shuffles we have found, to include them in our
|
|
// cost calculations.
|
|
if (!FromReduction) {
|
|
for (ShuffleVectorInst *SV : Shuffles) {
|
|
for (auto *U : SV->users()) {
|
|
ShuffleVectorInst *SSV = dyn_cast<ShuffleVectorInst>(U);
|
|
if (SSV && isa<UndefValue>(SSV->getOperand(1)) && SSV->getType() == VT)
|
|
Shuffles.push_back(SSV);
|
|
}
|
|
}
|
|
}
|
|
|
|
// For each of the output shuffles, we try to sort all the first vector
|
|
// elements to the beginning, followed by the second array elements at the
|
|
// end. If the binops are legalized to smaller vectors, this may reduce total
|
|
// number of binops. We compute the ReconstructMask mask needed to convert
|
|
// back to the original lane order.
|
|
SmallVector<std::pair<int, int>> V1, V2;
|
|
SmallVector<SmallVector<int>> OrigReconstructMasks;
|
|
int MaxV1Elt = 0, MaxV2Elt = 0;
|
|
unsigned NumElts = VT->getNumElements();
|
|
for (ShuffleVectorInst *SVN : Shuffles) {
|
|
SmallVector<int> Mask;
|
|
SVN->getShuffleMask(Mask);
|
|
|
|
// Check the operands are the same as the original, or reversed (in which
|
|
// case we need to commute the mask).
|
|
Value *SVOp0 = SVN->getOperand(0);
|
|
Value *SVOp1 = SVN->getOperand(1);
|
|
if (isa<UndefValue>(SVOp1)) {
|
|
auto *SSV = cast<ShuffleVectorInst>(SVOp0);
|
|
SVOp0 = SSV->getOperand(0);
|
|
SVOp1 = SSV->getOperand(1);
|
|
for (unsigned I = 0, E = Mask.size(); I != E; I++) {
|
|
if (Mask[I] >= static_cast<int>(SSV->getShuffleMask().size()))
|
|
return false;
|
|
Mask[I] = Mask[I] < 0 ? Mask[I] : SSV->getMaskValue(Mask[I]);
|
|
}
|
|
}
|
|
if (SVOp0 == Op1 && SVOp1 == Op0) {
|
|
std::swap(SVOp0, SVOp1);
|
|
ShuffleVectorInst::commuteShuffleMask(Mask, NumElts);
|
|
}
|
|
if (SVOp0 != Op0 || SVOp1 != Op1)
|
|
return false;
|
|
|
|
// Calculate the reconstruction mask for this shuffle, as the mask needed to
|
|
// take the packed values from Op0/Op1 and reconstructing to the original
|
|
// order.
|
|
SmallVector<int> ReconstructMask;
|
|
for (unsigned I = 0; I < Mask.size(); I++) {
|
|
if (Mask[I] < 0) {
|
|
ReconstructMask.push_back(-1);
|
|
} else if (Mask[I] < static_cast<int>(NumElts)) {
|
|
MaxV1Elt = std::max(MaxV1Elt, Mask[I]);
|
|
auto It = find_if(V1, [&](const std::pair<int, int> &A) {
|
|
return Mask[I] == A.first;
|
|
});
|
|
if (It != V1.end())
|
|
ReconstructMask.push_back(It - V1.begin());
|
|
else {
|
|
ReconstructMask.push_back(V1.size());
|
|
V1.emplace_back(Mask[I], V1.size());
|
|
}
|
|
} else {
|
|
MaxV2Elt = std::max<int>(MaxV2Elt, Mask[I] - NumElts);
|
|
auto It = find_if(V2, [&](const std::pair<int, int> &A) {
|
|
return Mask[I] - static_cast<int>(NumElts) == A.first;
|
|
});
|
|
if (It != V2.end())
|
|
ReconstructMask.push_back(NumElts + It - V2.begin());
|
|
else {
|
|
ReconstructMask.push_back(NumElts + V2.size());
|
|
V2.emplace_back(Mask[I] - NumElts, NumElts + V2.size());
|
|
}
|
|
}
|
|
}
|
|
|
|
// For reductions, we know that the lane ordering out doesn't alter the
|
|
// result. In-order can help simplify the shuffle away.
|
|
if (FromReduction)
|
|
sort(ReconstructMask);
|
|
OrigReconstructMasks.push_back(std::move(ReconstructMask));
|
|
}
|
|
|
|
// If the Maximum element used from V1 and V2 are not larger than the new
|
|
// vectors, the vectors are already packes and performing the optimization
|
|
// again will likely not help any further. This also prevents us from getting
|
|
// stuck in a cycle in case the costs do not also rule it out.
|
|
if (V1.empty() || V2.empty() ||
|
|
(MaxV1Elt == static_cast<int>(V1.size()) - 1 &&
|
|
MaxV2Elt == static_cast<int>(V2.size()) - 1))
|
|
return false;
|
|
|
|
// GetBaseMaskValue takes one of the inputs, which may either be a shuffle, a
|
|
// shuffle of another shuffle, or not a shuffle (that is treated like a
|
|
// identity shuffle).
|
|
auto GetBaseMaskValue = [&](Instruction *I, int M) {
|
|
auto *SV = dyn_cast<ShuffleVectorInst>(I);
|
|
if (!SV)
|
|
return M;
|
|
if (isa<UndefValue>(SV->getOperand(1)))
|
|
if (auto *SSV = dyn_cast<ShuffleVectorInst>(SV->getOperand(0)))
|
|
if (InputShuffles.contains(SSV))
|
|
return SSV->getMaskValue(SV->getMaskValue(M));
|
|
return SV->getMaskValue(M);
|
|
};
|
|
|
|
// Attempt to sort the inputs my ascending mask values to make simpler input
|
|
// shuffles and push complex shuffles down to the uses. We sort on the first
|
|
// of the two input shuffle orders, to try and get at least one input into a
|
|
// nice order.
|
|
auto SortBase = [&](Instruction *A, std::pair<int, int> X,
|
|
std::pair<int, int> Y) {
|
|
int MXA = GetBaseMaskValue(A, X.first);
|
|
int MYA = GetBaseMaskValue(A, Y.first);
|
|
return MXA < MYA;
|
|
};
|
|
stable_sort(V1, [&](std::pair<int, int> A, std::pair<int, int> B) {
|
|
return SortBase(SVI0A, A, B);
|
|
});
|
|
stable_sort(V2, [&](std::pair<int, int> A, std::pair<int, int> B) {
|
|
return SortBase(SVI1A, A, B);
|
|
});
|
|
// Calculate our ReconstructMasks from the OrigReconstructMasks and the
|
|
// modified order of the input shuffles.
|
|
SmallVector<SmallVector<int>> ReconstructMasks;
|
|
for (const auto &Mask : OrigReconstructMasks) {
|
|
SmallVector<int> ReconstructMask;
|
|
for (int M : Mask) {
|
|
auto FindIndex = [](const SmallVector<std::pair<int, int>> &V, int M) {
|
|
auto It = find_if(V, [M](auto A) { return A.second == M; });
|
|
assert(It != V.end() && "Expected all entries in Mask");
|
|
return std::distance(V.begin(), It);
|
|
};
|
|
if (M < 0)
|
|
ReconstructMask.push_back(-1);
|
|
else if (M < static_cast<int>(NumElts)) {
|
|
ReconstructMask.push_back(FindIndex(V1, M));
|
|
} else {
|
|
ReconstructMask.push_back(NumElts + FindIndex(V2, M));
|
|
}
|
|
}
|
|
ReconstructMasks.push_back(std::move(ReconstructMask));
|
|
}
|
|
|
|
// Calculate the masks needed for the new input shuffles, which get padded
|
|
// with undef
|
|
SmallVector<int> V1A, V1B, V2A, V2B;
|
|
for (unsigned I = 0; I < V1.size(); I++) {
|
|
V1A.push_back(GetBaseMaskValue(SVI0A, V1[I].first));
|
|
V1B.push_back(GetBaseMaskValue(SVI0B, V1[I].first));
|
|
}
|
|
for (unsigned I = 0; I < V2.size(); I++) {
|
|
V2A.push_back(GetBaseMaskValue(SVI1A, V2[I].first));
|
|
V2B.push_back(GetBaseMaskValue(SVI1B, V2[I].first));
|
|
}
|
|
while (V1A.size() < NumElts) {
|
|
V1A.push_back(PoisonMaskElem);
|
|
V1B.push_back(PoisonMaskElem);
|
|
}
|
|
while (V2A.size() < NumElts) {
|
|
V2A.push_back(PoisonMaskElem);
|
|
V2B.push_back(PoisonMaskElem);
|
|
}
|
|
|
|
auto AddShuffleCost = [&](InstructionCost C, Instruction *I) {
|
|
auto *SV = dyn_cast<ShuffleVectorInst>(I);
|
|
if (!SV)
|
|
return C;
|
|
return C + TTI.getShuffleCost(isa<UndefValue>(SV->getOperand(1))
|
|
? TTI::SK_PermuteSingleSrc
|
|
: TTI::SK_PermuteTwoSrc,
|
|
VT, SV->getShuffleMask(), CostKind);
|
|
};
|
|
auto AddShuffleMaskCost = [&](InstructionCost C, ArrayRef<int> Mask) {
|
|
return C + TTI.getShuffleCost(TTI::SK_PermuteTwoSrc, VT, Mask, CostKind);
|
|
};
|
|
|
|
// Get the costs of the shuffles + binops before and after with the new
|
|
// shuffle masks.
|
|
InstructionCost CostBefore =
|
|
TTI.getArithmeticInstrCost(Op0->getOpcode(), VT, CostKind) +
|
|
TTI.getArithmeticInstrCost(Op1->getOpcode(), VT, CostKind);
|
|
CostBefore += std::accumulate(Shuffles.begin(), Shuffles.end(),
|
|
InstructionCost(0), AddShuffleCost);
|
|
CostBefore += std::accumulate(InputShuffles.begin(), InputShuffles.end(),
|
|
InstructionCost(0), AddShuffleCost);
|
|
|
|
// The new binops will be unused for lanes past the used shuffle lengths.
|
|
// These types attempt to get the correct cost for that from the target.
|
|
FixedVectorType *Op0SmallVT =
|
|
FixedVectorType::get(VT->getScalarType(), V1.size());
|
|
FixedVectorType *Op1SmallVT =
|
|
FixedVectorType::get(VT->getScalarType(), V2.size());
|
|
InstructionCost CostAfter =
|
|
TTI.getArithmeticInstrCost(Op0->getOpcode(), Op0SmallVT, CostKind) +
|
|
TTI.getArithmeticInstrCost(Op1->getOpcode(), Op1SmallVT, CostKind);
|
|
CostAfter += std::accumulate(ReconstructMasks.begin(), ReconstructMasks.end(),
|
|
InstructionCost(0), AddShuffleMaskCost);
|
|
std::set<SmallVector<int>> OutputShuffleMasks({V1A, V1B, V2A, V2B});
|
|
CostAfter +=
|
|
std::accumulate(OutputShuffleMasks.begin(), OutputShuffleMasks.end(),
|
|
InstructionCost(0), AddShuffleMaskCost);
|
|
|
|
LLVM_DEBUG(dbgs() << "Found a binop select shuffle pattern: " << I << "\n");
|
|
LLVM_DEBUG(dbgs() << " CostBefore: " << CostBefore
|
|
<< " vs CostAfter: " << CostAfter << "\n");
|
|
if (CostBefore <= CostAfter)
|
|
return false;
|
|
|
|
// The cost model has passed, create the new instructions.
|
|
auto GetShuffleOperand = [&](Instruction *I, unsigned Op) -> Value * {
|
|
auto *SV = dyn_cast<ShuffleVectorInst>(I);
|
|
if (!SV)
|
|
return I;
|
|
if (isa<UndefValue>(SV->getOperand(1)))
|
|
if (auto *SSV = dyn_cast<ShuffleVectorInst>(SV->getOperand(0)))
|
|
if (InputShuffles.contains(SSV))
|
|
return SSV->getOperand(Op);
|
|
return SV->getOperand(Op);
|
|
};
|
|
Builder.SetInsertPoint(*SVI0A->getInsertionPointAfterDef());
|
|
Value *NSV0A = Builder.CreateShuffleVector(GetShuffleOperand(SVI0A, 0),
|
|
GetShuffleOperand(SVI0A, 1), V1A);
|
|
Builder.SetInsertPoint(*SVI0B->getInsertionPointAfterDef());
|
|
Value *NSV0B = Builder.CreateShuffleVector(GetShuffleOperand(SVI0B, 0),
|
|
GetShuffleOperand(SVI0B, 1), V1B);
|
|
Builder.SetInsertPoint(*SVI1A->getInsertionPointAfterDef());
|
|
Value *NSV1A = Builder.CreateShuffleVector(GetShuffleOperand(SVI1A, 0),
|
|
GetShuffleOperand(SVI1A, 1), V2A);
|
|
Builder.SetInsertPoint(*SVI1B->getInsertionPointAfterDef());
|
|
Value *NSV1B = Builder.CreateShuffleVector(GetShuffleOperand(SVI1B, 0),
|
|
GetShuffleOperand(SVI1B, 1), V2B);
|
|
Builder.SetInsertPoint(Op0);
|
|
Value *NOp0 = Builder.CreateBinOp((Instruction::BinaryOps)Op0->getOpcode(),
|
|
NSV0A, NSV0B);
|
|
if (auto *I = dyn_cast<Instruction>(NOp0))
|
|
I->copyIRFlags(Op0, true);
|
|
Builder.SetInsertPoint(Op1);
|
|
Value *NOp1 = Builder.CreateBinOp((Instruction::BinaryOps)Op1->getOpcode(),
|
|
NSV1A, NSV1B);
|
|
if (auto *I = dyn_cast<Instruction>(NOp1))
|
|
I->copyIRFlags(Op1, true);
|
|
|
|
for (int S = 0, E = ReconstructMasks.size(); S != E; S++) {
|
|
Builder.SetInsertPoint(Shuffles[S]);
|
|
Value *NSV = Builder.CreateShuffleVector(NOp0, NOp1, ReconstructMasks[S]);
|
|
replaceValue(*Shuffles[S], *NSV);
|
|
}
|
|
|
|
Worklist.pushValue(NSV0A);
|
|
Worklist.pushValue(NSV0B);
|
|
Worklist.pushValue(NSV1A);
|
|
Worklist.pushValue(NSV1B);
|
|
for (auto *S : Shuffles)
|
|
Worklist.add(S);
|
|
return true;
|
|
}
|
|
|
|
/// Check if instruction depends on ZExt and this ZExt can be moved after the
|
|
/// instruction. Move ZExt if it is profitable. For example:
|
|
/// logic(zext(x),y) -> zext(logic(x,trunc(y)))
|
|
/// lshr((zext(x),y) -> zext(lshr(x,trunc(y)))
|
|
/// Cost model calculations takes into account if zext(x) has other users and
|
|
/// whether it can be propagated through them too.
|
|
bool VectorCombine::shrinkType(Instruction &I) {
|
|
Value *ZExted, *OtherOperand;
|
|
if (!match(&I, m_c_BitwiseLogic(m_ZExt(m_Value(ZExted)),
|
|
m_Value(OtherOperand))) &&
|
|
!match(&I, m_LShr(m_ZExt(m_Value(ZExted)), m_Value(OtherOperand))))
|
|
return false;
|
|
|
|
Value *ZExtOperand = I.getOperand(I.getOperand(0) == OtherOperand ? 1 : 0);
|
|
|
|
auto *BigTy = cast<FixedVectorType>(I.getType());
|
|
auto *SmallTy = cast<FixedVectorType>(ZExted->getType());
|
|
unsigned BW = SmallTy->getElementType()->getPrimitiveSizeInBits();
|
|
|
|
if (I.getOpcode() == Instruction::LShr) {
|
|
// Check that the shift amount is less than the number of bits in the
|
|
// smaller type. Otherwise, the smaller lshr will return a poison value.
|
|
KnownBits ShAmtKB = computeKnownBits(I.getOperand(1), *DL);
|
|
if (ShAmtKB.getMaxValue().uge(BW))
|
|
return false;
|
|
} else {
|
|
// Check that the expression overall uses at most the same number of bits as
|
|
// ZExted
|
|
KnownBits KB = computeKnownBits(&I, *DL);
|
|
if (KB.countMaxActiveBits() > BW)
|
|
return false;
|
|
}
|
|
|
|
// Calculate costs of leaving current IR as it is and moving ZExt operation
|
|
// later, along with adding truncates if needed
|
|
InstructionCost ZExtCost = TTI.getCastInstrCost(
|
|
Instruction::ZExt, BigTy, SmallTy,
|
|
TargetTransformInfo::CastContextHint::None, CostKind);
|
|
InstructionCost CurrentCost = ZExtCost;
|
|
InstructionCost ShrinkCost = 0;
|
|
|
|
// Calculate total cost and check that we can propagate through all ZExt users
|
|
for (User *U : ZExtOperand->users()) {
|
|
auto *UI = cast<Instruction>(U);
|
|
if (UI == &I) {
|
|
CurrentCost +=
|
|
TTI.getArithmeticInstrCost(UI->getOpcode(), BigTy, CostKind);
|
|
ShrinkCost +=
|
|
TTI.getArithmeticInstrCost(UI->getOpcode(), SmallTy, CostKind);
|
|
ShrinkCost += ZExtCost;
|
|
continue;
|
|
}
|
|
|
|
if (!Instruction::isBinaryOp(UI->getOpcode()))
|
|
return false;
|
|
|
|
// Check if we can propagate ZExt through its other users
|
|
KnownBits KB = computeKnownBits(UI, *DL);
|
|
if (KB.countMaxActiveBits() > BW)
|
|
return false;
|
|
|
|
CurrentCost += TTI.getArithmeticInstrCost(UI->getOpcode(), BigTy, CostKind);
|
|
ShrinkCost +=
|
|
TTI.getArithmeticInstrCost(UI->getOpcode(), SmallTy, CostKind);
|
|
ShrinkCost += ZExtCost;
|
|
}
|
|
|
|
// If the other instruction operand is not a constant, we'll need to
|
|
// generate a truncate instruction. So we have to adjust cost
|
|
if (!isa<Constant>(OtherOperand))
|
|
ShrinkCost += TTI.getCastInstrCost(
|
|
Instruction::Trunc, SmallTy, BigTy,
|
|
TargetTransformInfo::CastContextHint::None, CostKind);
|
|
|
|
// If the cost of shrinking types and leaving the IR is the same, we'll lean
|
|
// towards modifying the IR because shrinking opens opportunities for other
|
|
// shrinking optimisations.
|
|
if (ShrinkCost > CurrentCost)
|
|
return false;
|
|
|
|
Builder.SetInsertPoint(&I);
|
|
Value *Op0 = ZExted;
|
|
Value *Op1 = Builder.CreateTrunc(OtherOperand, SmallTy);
|
|
// Keep the order of operands the same
|
|
if (I.getOperand(0) == OtherOperand)
|
|
std::swap(Op0, Op1);
|
|
Value *NewBinOp =
|
|
Builder.CreateBinOp((Instruction::BinaryOps)I.getOpcode(), Op0, Op1);
|
|
cast<Instruction>(NewBinOp)->copyIRFlags(&I);
|
|
cast<Instruction>(NewBinOp)->copyMetadata(I);
|
|
Value *NewZExtr = Builder.CreateZExt(NewBinOp, BigTy);
|
|
replaceValue(I, *NewZExtr);
|
|
return true;
|
|
}
|
|
|
|
/// insert (DstVec, (extract SrcVec, ExtIdx), InsIdx) -->
|
|
/// shuffle (DstVec, SrcVec, Mask)
|
|
bool VectorCombine::foldInsExtVectorToShuffle(Instruction &I) {
|
|
Value *DstVec, *SrcVec;
|
|
uint64_t ExtIdx, InsIdx;
|
|
if (!match(&I,
|
|
m_InsertElt(m_Value(DstVec),
|
|
m_ExtractElt(m_Value(SrcVec), m_ConstantInt(ExtIdx)),
|
|
m_ConstantInt(InsIdx))))
|
|
return false;
|
|
|
|
auto *VecTy = dyn_cast<FixedVectorType>(I.getType());
|
|
if (!VecTy || SrcVec->getType() != VecTy)
|
|
return false;
|
|
|
|
unsigned NumElts = VecTy->getNumElements();
|
|
if (ExtIdx >= NumElts || InsIdx >= NumElts)
|
|
return false;
|
|
|
|
// Insertion into poison is a cheaper single operand shuffle.
|
|
TargetTransformInfo::ShuffleKind SK;
|
|
SmallVector<int> Mask(NumElts, PoisonMaskElem);
|
|
if (isa<PoisonValue>(DstVec) && !isa<UndefValue>(SrcVec)) {
|
|
SK = TargetTransformInfo::SK_PermuteSingleSrc;
|
|
Mask[InsIdx] = ExtIdx;
|
|
std::swap(DstVec, SrcVec);
|
|
} else {
|
|
SK = TargetTransformInfo::SK_PermuteTwoSrc;
|
|
std::iota(Mask.begin(), Mask.end(), 0);
|
|
Mask[InsIdx] = ExtIdx + NumElts;
|
|
}
|
|
|
|
// Cost
|
|
auto *Ins = cast<InsertElementInst>(&I);
|
|
auto *Ext = cast<ExtractElementInst>(I.getOperand(1));
|
|
InstructionCost InsCost =
|
|
TTI.getVectorInstrCost(*Ins, VecTy, CostKind, InsIdx);
|
|
InstructionCost ExtCost =
|
|
TTI.getVectorInstrCost(*Ext, VecTy, CostKind, ExtIdx);
|
|
InstructionCost OldCost = ExtCost + InsCost;
|
|
|
|
// Ignore 'free' identity insertion shuffle.
|
|
// TODO: getShuffleCost should return TCC_Free for Identity shuffles.
|
|
InstructionCost NewCost = 0;
|
|
if (!ShuffleVectorInst::isIdentityMask(Mask, NumElts))
|
|
NewCost += TTI.getShuffleCost(SK, VecTy, Mask, CostKind, 0, nullptr,
|
|
{DstVec, SrcVec});
|
|
if (!Ext->hasOneUse())
|
|
NewCost += ExtCost;
|
|
|
|
LLVM_DEBUG(dbgs() << "Found a insert/extract shuffle-like pair: " << I
|
|
<< "\n OldCost: " << OldCost << " vs NewCost: " << NewCost
|
|
<< "\n");
|
|
|
|
if (OldCost < NewCost)
|
|
return false;
|
|
|
|
// Canonicalize undef param to RHS to help further folds.
|
|
if (isa<UndefValue>(DstVec) && !isa<UndefValue>(SrcVec)) {
|
|
ShuffleVectorInst::commuteShuffleMask(Mask, NumElts);
|
|
std::swap(DstVec, SrcVec);
|
|
}
|
|
|
|
Value *Shuf = Builder.CreateShuffleVector(DstVec, SrcVec, Mask);
|
|
replaceValue(I, *Shuf);
|
|
|
|
return true;
|
|
}
|
|
|
|
/// This is the entry point for all transforms. Pass manager differences are
|
|
/// handled in the callers of this function.
|
|
bool VectorCombine::run() {
|
|
if (DisableVectorCombine)
|
|
return false;
|
|
|
|
// Don't attempt vectorization if the target does not support vectors.
|
|
if (!TTI.getNumberOfRegisters(TTI.getRegisterClassForType(/*Vector*/ true)))
|
|
return false;
|
|
|
|
LLVM_DEBUG(dbgs() << "\n\nVECTORCOMBINE on " << F.getName() << "\n");
|
|
|
|
bool MadeChange = false;
|
|
auto FoldInst = [this, &MadeChange](Instruction &I) {
|
|
Builder.SetInsertPoint(&I);
|
|
bool IsVectorType = isa<VectorType>(I.getType());
|
|
bool IsFixedVectorType = isa<FixedVectorType>(I.getType());
|
|
auto Opcode = I.getOpcode();
|
|
|
|
LLVM_DEBUG(dbgs() << "VC: Visiting: " << I << '\n');
|
|
|
|
// These folds should be beneficial regardless of when this pass is run
|
|
// in the optimization pipeline.
|
|
// The type checking is for run-time efficiency. We can avoid wasting time
|
|
// dispatching to folding functions if there's no chance of matching.
|
|
if (IsFixedVectorType) {
|
|
switch (Opcode) {
|
|
case Instruction::InsertElement:
|
|
MadeChange |= vectorizeLoadInsert(I);
|
|
break;
|
|
case Instruction::ShuffleVector:
|
|
MadeChange |= widenSubvectorLoad(I);
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
// This transform works with scalable and fixed vectors
|
|
// TODO: Identify and allow other scalable transforms
|
|
if (IsVectorType) {
|
|
MadeChange |= scalarizeBinopOrCmp(I);
|
|
MadeChange |= scalarizeLoadExtract(I);
|
|
MadeChange |= scalarizeVPIntrinsic(I);
|
|
}
|
|
|
|
if (Opcode == Instruction::Store)
|
|
MadeChange |= foldSingleElementStore(I);
|
|
|
|
// If this is an early pipeline invocation of this pass, we are done.
|
|
if (TryEarlyFoldsOnly)
|
|
return;
|
|
|
|
// Otherwise, try folds that improve codegen but may interfere with
|
|
// early IR canonicalizations.
|
|
// The type checking is for run-time efficiency. We can avoid wasting time
|
|
// dispatching to folding functions if there's no chance of matching.
|
|
if (IsFixedVectorType) {
|
|
switch (Opcode) {
|
|
case Instruction::InsertElement:
|
|
MadeChange |= foldInsExtFNeg(I);
|
|
MadeChange |= foldInsExtVectorToShuffle(I);
|
|
break;
|
|
case Instruction::ShuffleVector:
|
|
MadeChange |= foldPermuteOfBinops(I);
|
|
MadeChange |= foldShuffleOfBinops(I);
|
|
MadeChange |= foldShuffleOfCastops(I);
|
|
MadeChange |= foldShuffleOfShuffles(I);
|
|
MadeChange |= foldShuffleOfIntrinsics(I);
|
|
MadeChange |= foldSelectShuffle(I);
|
|
MadeChange |= foldShuffleToIdentity(I);
|
|
break;
|
|
case Instruction::BitCast:
|
|
MadeChange |= foldBitcastShuffle(I);
|
|
break;
|
|
default:
|
|
MadeChange |= shrinkType(I);
|
|
break;
|
|
}
|
|
} else {
|
|
switch (Opcode) {
|
|
case Instruction::Call:
|
|
MadeChange |= foldShuffleFromReductions(I);
|
|
MadeChange |= foldCastFromReductions(I);
|
|
break;
|
|
case Instruction::ICmp:
|
|
case Instruction::FCmp:
|
|
MadeChange |= foldExtractExtract(I);
|
|
break;
|
|
case Instruction::Or:
|
|
MadeChange |= foldConcatOfBoolMasks(I);
|
|
[[fallthrough]];
|
|
default:
|
|
if (Instruction::isBinaryOp(Opcode)) {
|
|
MadeChange |= foldExtractExtract(I);
|
|
MadeChange |= foldExtractedCmps(I);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
};
|
|
|
|
for (BasicBlock &BB : F) {
|
|
// Ignore unreachable basic blocks.
|
|
if (!DT.isReachableFromEntry(&BB))
|
|
continue;
|
|
// Use early increment range so that we can erase instructions in loop.
|
|
for (Instruction &I : make_early_inc_range(BB)) {
|
|
if (I.isDebugOrPseudoInst())
|
|
continue;
|
|
FoldInst(I);
|
|
}
|
|
}
|
|
|
|
while (!Worklist.isEmpty()) {
|
|
Instruction *I = Worklist.removeOne();
|
|
if (!I)
|
|
continue;
|
|
|
|
if (isInstructionTriviallyDead(I)) {
|
|
eraseInstruction(*I);
|
|
continue;
|
|
}
|
|
|
|
FoldInst(*I);
|
|
}
|
|
|
|
return MadeChange;
|
|
}
|
|
|
|
PreservedAnalyses VectorCombinePass::run(Function &F,
|
|
FunctionAnalysisManager &FAM) {
|
|
auto &AC = FAM.getResult<AssumptionAnalysis>(F);
|
|
TargetTransformInfo &TTI = FAM.getResult<TargetIRAnalysis>(F);
|
|
DominatorTree &DT = FAM.getResult<DominatorTreeAnalysis>(F);
|
|
AAResults &AA = FAM.getResult<AAManager>(F);
|
|
const DataLayout *DL = &F.getDataLayout();
|
|
VectorCombine Combiner(F, TTI, DT, AA, AC, DL, TTI::TCK_RecipThroughput,
|
|
TryEarlyFoldsOnly);
|
|
if (!Combiner.run())
|
|
return PreservedAnalyses::all();
|
|
PreservedAnalyses PA;
|
|
PA.preserveSet<CFGAnalyses>();
|
|
return PA;
|
|
}
|