forked from OSchip/llvm-project
1424 lines
51 KiB
C++
1424 lines
51 KiB
C++
//===----------- VectorUtils.cpp - Vectorizer utility functions -----------===//
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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 file defines vectorizer utilities.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/VectorUtils.h"
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#include "llvm/ADT/EquivalenceClasses.h"
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#include "llvm/Analysis/DemandedBits.h"
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/Analysis/LoopIterator.h"
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#include "llvm/Analysis/ScalarEvolution.h"
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#include "llvm/Analysis/ScalarEvolutionExpressions.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/IR/Constants.h"
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#include "llvm/IR/GetElementPtrTypeIterator.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/IR/Value.h"
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#include "llvm/Support/CommandLine.h"
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#define DEBUG_TYPE "vectorutils"
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using namespace llvm;
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using namespace llvm::PatternMatch;
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/// Maximum factor for an interleaved memory access.
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static cl::opt<unsigned> MaxInterleaveGroupFactor(
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"max-interleave-group-factor", cl::Hidden,
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cl::desc("Maximum factor for an interleaved access group (default = 8)"),
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cl::init(8));
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/// Return true if all of the intrinsic's arguments and return type are scalars
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/// for the scalar form of the intrinsic, and vectors for the vector form of the
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/// intrinsic (except operands that are marked as always being scalar by
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/// hasVectorInstrinsicScalarOpd).
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bool llvm::isTriviallyVectorizable(Intrinsic::ID ID) {
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switch (ID) {
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case Intrinsic::abs: // Begin integer bit-manipulation.
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case Intrinsic::bswap:
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case Intrinsic::bitreverse:
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case Intrinsic::ctpop:
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case Intrinsic::ctlz:
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case Intrinsic::cttz:
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case Intrinsic::fshl:
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case Intrinsic::fshr:
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case Intrinsic::smax:
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case Intrinsic::smin:
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case Intrinsic::umax:
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case Intrinsic::umin:
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case Intrinsic::sadd_sat:
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case Intrinsic::ssub_sat:
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case Intrinsic::uadd_sat:
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case Intrinsic::usub_sat:
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case Intrinsic::smul_fix:
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case Intrinsic::smul_fix_sat:
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case Intrinsic::umul_fix:
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case Intrinsic::umul_fix_sat:
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case Intrinsic::sqrt: // Begin floating-point.
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case Intrinsic::sin:
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case Intrinsic::cos:
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case Intrinsic::exp:
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case Intrinsic::exp2:
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case Intrinsic::log:
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case Intrinsic::log10:
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case Intrinsic::log2:
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case Intrinsic::fabs:
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case Intrinsic::minnum:
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case Intrinsic::maxnum:
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case Intrinsic::minimum:
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case Intrinsic::maximum:
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case Intrinsic::copysign:
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case Intrinsic::floor:
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case Intrinsic::ceil:
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case Intrinsic::trunc:
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case Intrinsic::rint:
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case Intrinsic::nearbyint:
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case Intrinsic::round:
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case Intrinsic::roundeven:
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case Intrinsic::pow:
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case Intrinsic::fma:
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case Intrinsic::fmuladd:
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case Intrinsic::powi:
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case Intrinsic::canonicalize:
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return true;
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default:
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return false;
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}
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}
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/// Identifies if the vector form of the intrinsic has a scalar operand.
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bool llvm::hasVectorInstrinsicScalarOpd(Intrinsic::ID ID,
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unsigned ScalarOpdIdx) {
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switch (ID) {
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case Intrinsic::abs:
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case Intrinsic::ctlz:
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case Intrinsic::cttz:
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case Intrinsic::powi:
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return (ScalarOpdIdx == 1);
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case Intrinsic::smul_fix:
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case Intrinsic::smul_fix_sat:
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case Intrinsic::umul_fix:
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case Intrinsic::umul_fix_sat:
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return (ScalarOpdIdx == 2);
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default:
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return false;
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}
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}
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bool llvm::hasVectorInstrinsicOverloadedScalarOpd(Intrinsic::ID ID,
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unsigned ScalarOpdIdx) {
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switch (ID) {
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case Intrinsic::powi:
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return (ScalarOpdIdx == 1);
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default:
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return false;
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}
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}
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/// Returns intrinsic ID for call.
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/// For the input call instruction it finds mapping intrinsic and returns
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/// its ID, in case it does not found it return not_intrinsic.
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Intrinsic::ID llvm::getVectorIntrinsicIDForCall(const CallInst *CI,
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const TargetLibraryInfo *TLI) {
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Intrinsic::ID ID = getIntrinsicForCallSite(*CI, TLI);
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if (ID == Intrinsic::not_intrinsic)
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return Intrinsic::not_intrinsic;
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if (isTriviallyVectorizable(ID) || ID == Intrinsic::lifetime_start ||
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ID == Intrinsic::lifetime_end || ID == Intrinsic::assume ||
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ID == Intrinsic::experimental_noalias_scope_decl ||
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ID == Intrinsic::sideeffect || ID == Intrinsic::pseudoprobe)
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return ID;
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return Intrinsic::not_intrinsic;
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}
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/// Find the operand of the GEP that should be checked for consecutive
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/// stores. This ignores trailing indices that have no effect on the final
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/// pointer.
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unsigned llvm::getGEPInductionOperand(const GetElementPtrInst *Gep) {
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const DataLayout &DL = Gep->getModule()->getDataLayout();
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unsigned LastOperand = Gep->getNumOperands() - 1;
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TypeSize GEPAllocSize = DL.getTypeAllocSize(Gep->getResultElementType());
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// Walk backwards and try to peel off zeros.
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while (LastOperand > 1 && match(Gep->getOperand(LastOperand), m_Zero())) {
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// Find the type we're currently indexing into.
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gep_type_iterator GEPTI = gep_type_begin(Gep);
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std::advance(GEPTI, LastOperand - 2);
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// If it's a type with the same allocation size as the result of the GEP we
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// can peel off the zero index.
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if (DL.getTypeAllocSize(GEPTI.getIndexedType()) != GEPAllocSize)
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break;
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--LastOperand;
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}
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return LastOperand;
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}
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/// If the argument is a GEP, then returns the operand identified by
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/// getGEPInductionOperand. However, if there is some other non-loop-invariant
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/// operand, it returns that instead.
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Value *llvm::stripGetElementPtr(Value *Ptr, ScalarEvolution *SE, Loop *Lp) {
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GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Ptr);
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if (!GEP)
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return Ptr;
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unsigned InductionOperand = getGEPInductionOperand(GEP);
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// Check that all of the gep indices are uniform except for our induction
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// operand.
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for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i)
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if (i != InductionOperand &&
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!SE->isLoopInvariant(SE->getSCEV(GEP->getOperand(i)), Lp))
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return Ptr;
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return GEP->getOperand(InductionOperand);
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}
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/// If a value has only one user that is a CastInst, return it.
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Value *llvm::getUniqueCastUse(Value *Ptr, Loop *Lp, Type *Ty) {
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Value *UniqueCast = nullptr;
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for (User *U : Ptr->users()) {
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CastInst *CI = dyn_cast<CastInst>(U);
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if (CI && CI->getType() == Ty) {
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if (!UniqueCast)
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UniqueCast = CI;
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else
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return nullptr;
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}
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}
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return UniqueCast;
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}
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/// Get the stride of a pointer access in a loop. Looks for symbolic
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/// strides "a[i*stride]". Returns the symbolic stride, or null otherwise.
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Value *llvm::getStrideFromPointer(Value *Ptr, ScalarEvolution *SE, Loop *Lp) {
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auto *PtrTy = dyn_cast<PointerType>(Ptr->getType());
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if (!PtrTy || PtrTy->isAggregateType())
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return nullptr;
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// Try to remove a gep instruction to make the pointer (actually index at this
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// point) easier analyzable. If OrigPtr is equal to Ptr we are analyzing the
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// pointer, otherwise, we are analyzing the index.
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Value *OrigPtr = Ptr;
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// The size of the pointer access.
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int64_t PtrAccessSize = 1;
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Ptr = stripGetElementPtr(Ptr, SE, Lp);
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const SCEV *V = SE->getSCEV(Ptr);
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if (Ptr != OrigPtr)
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// Strip off casts.
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while (const SCEVIntegralCastExpr *C = dyn_cast<SCEVIntegralCastExpr>(V))
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V = C->getOperand();
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const SCEVAddRecExpr *S = dyn_cast<SCEVAddRecExpr>(V);
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if (!S)
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return nullptr;
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V = S->getStepRecurrence(*SE);
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if (!V)
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return nullptr;
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// Strip off the size of access multiplication if we are still analyzing the
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// pointer.
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if (OrigPtr == Ptr) {
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if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(V)) {
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if (M->getOperand(0)->getSCEVType() != scConstant)
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return nullptr;
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const APInt &APStepVal = cast<SCEVConstant>(M->getOperand(0))->getAPInt();
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// Huge step value - give up.
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if (APStepVal.getBitWidth() > 64)
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return nullptr;
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int64_t StepVal = APStepVal.getSExtValue();
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if (PtrAccessSize != StepVal)
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return nullptr;
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V = M->getOperand(1);
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}
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}
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// Strip off casts.
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Type *StripedOffRecurrenceCast = nullptr;
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if (const SCEVIntegralCastExpr *C = dyn_cast<SCEVIntegralCastExpr>(V)) {
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StripedOffRecurrenceCast = C->getType();
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V = C->getOperand();
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}
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// Look for the loop invariant symbolic value.
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const SCEVUnknown *U = dyn_cast<SCEVUnknown>(V);
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if (!U)
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return nullptr;
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Value *Stride = U->getValue();
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if (!Lp->isLoopInvariant(Stride))
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return nullptr;
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// If we have stripped off the recurrence cast we have to make sure that we
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// return the value that is used in this loop so that we can replace it later.
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if (StripedOffRecurrenceCast)
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Stride = getUniqueCastUse(Stride, Lp, StripedOffRecurrenceCast);
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return Stride;
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}
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/// Given a vector and an element number, see if the scalar value is
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/// already around as a register, for example if it were inserted then extracted
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/// from the vector.
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Value *llvm::findScalarElement(Value *V, unsigned EltNo) {
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assert(V->getType()->isVectorTy() && "Not looking at a vector?");
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VectorType *VTy = cast<VectorType>(V->getType());
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// For fixed-length vector, return undef for out of range access.
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if (auto *FVTy = dyn_cast<FixedVectorType>(VTy)) {
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unsigned Width = FVTy->getNumElements();
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if (EltNo >= Width)
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return UndefValue::get(FVTy->getElementType());
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}
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if (Constant *C = dyn_cast<Constant>(V))
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return C->getAggregateElement(EltNo);
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if (InsertElementInst *III = dyn_cast<InsertElementInst>(V)) {
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// If this is an insert to a variable element, we don't know what it is.
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if (!isa<ConstantInt>(III->getOperand(2)))
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return nullptr;
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unsigned IIElt = cast<ConstantInt>(III->getOperand(2))->getZExtValue();
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// If this is an insert to the element we are looking for, return the
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// inserted value.
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if (EltNo == IIElt)
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return III->getOperand(1);
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// Guard against infinite loop on malformed, unreachable IR.
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if (III == III->getOperand(0))
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return nullptr;
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// Otherwise, the insertelement doesn't modify the value, recurse on its
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// vector input.
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return findScalarElement(III->getOperand(0), EltNo);
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}
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ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(V);
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// Restrict the following transformation to fixed-length vector.
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if (SVI && isa<FixedVectorType>(SVI->getType())) {
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unsigned LHSWidth =
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cast<FixedVectorType>(SVI->getOperand(0)->getType())->getNumElements();
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int InEl = SVI->getMaskValue(EltNo);
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if (InEl < 0)
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return UndefValue::get(VTy->getElementType());
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if (InEl < (int)LHSWidth)
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return findScalarElement(SVI->getOperand(0), InEl);
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return findScalarElement(SVI->getOperand(1), InEl - LHSWidth);
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}
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// Extract a value from a vector add operation with a constant zero.
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// TODO: Use getBinOpIdentity() to generalize this.
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Value *Val; Constant *C;
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if (match(V, m_Add(m_Value(Val), m_Constant(C))))
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if (Constant *Elt = C->getAggregateElement(EltNo))
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if (Elt->isNullValue())
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return findScalarElement(Val, EltNo);
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// If the vector is a splat then we can trivially find the scalar element.
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if (isa<ScalableVectorType>(VTy))
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if (Value *Splat = getSplatValue(V))
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if (EltNo < VTy->getElementCount().getKnownMinValue())
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return Splat;
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// Otherwise, we don't know.
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return nullptr;
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}
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int llvm::getSplatIndex(ArrayRef<int> Mask) {
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int SplatIndex = -1;
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for (int M : Mask) {
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// Ignore invalid (undefined) mask elements.
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if (M < 0)
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continue;
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// There can be only 1 non-negative mask element value if this is a splat.
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if (SplatIndex != -1 && SplatIndex != M)
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return -1;
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// Initialize the splat index to the 1st non-negative mask element.
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SplatIndex = M;
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}
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assert((SplatIndex == -1 || SplatIndex >= 0) && "Negative index?");
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return SplatIndex;
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}
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/// Get splat value if the input is a splat vector or return nullptr.
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/// This function is not fully general. It checks only 2 cases:
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/// the input value is (1) a splat constant vector or (2) a sequence
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/// of instructions that broadcasts a scalar at element 0.
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Value *llvm::getSplatValue(const Value *V) {
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if (isa<VectorType>(V->getType()))
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if (auto *C = dyn_cast<Constant>(V))
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return C->getSplatValue();
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// shuf (inselt ?, Splat, 0), ?, <0, undef, 0, ...>
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Value *Splat;
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if (match(V,
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m_Shuffle(m_InsertElt(m_Value(), m_Value(Splat), m_ZeroInt()),
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m_Value(), m_ZeroMask())))
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return Splat;
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return nullptr;
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}
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bool llvm::isSplatValue(const Value *V, int Index, unsigned Depth) {
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assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth");
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if (isa<VectorType>(V->getType())) {
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if (isa<UndefValue>(V))
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return true;
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// FIXME: We can allow undefs, but if Index was specified, we may want to
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// check that the constant is defined at that index.
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if (auto *C = dyn_cast<Constant>(V))
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return C->getSplatValue() != nullptr;
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}
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if (auto *Shuf = dyn_cast<ShuffleVectorInst>(V)) {
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// FIXME: We can safely allow undefs here. If Index was specified, we will
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// check that the mask elt is defined at the required index.
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if (!is_splat(Shuf->getShuffleMask()))
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return false;
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// Match any index.
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if (Index == -1)
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return true;
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// Match a specific element. The mask should be defined at and match the
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// specified index.
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return Shuf->getMaskValue(Index) == Index;
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}
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// The remaining tests are all recursive, so bail out if we hit the limit.
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if (Depth++ == MaxAnalysisRecursionDepth)
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return false;
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// If both operands of a binop are splats, the result is a splat.
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Value *X, *Y, *Z;
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if (match(V, m_BinOp(m_Value(X), m_Value(Y))))
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return isSplatValue(X, Index, Depth) && isSplatValue(Y, Index, Depth);
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// If all operands of a select are splats, the result is a splat.
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if (match(V, m_Select(m_Value(X), m_Value(Y), m_Value(Z))))
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return isSplatValue(X, Index, Depth) && isSplatValue(Y, Index, Depth) &&
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isSplatValue(Z, Index, Depth);
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// TODO: Add support for unary ops (fneg), casts, intrinsics (overflow ops).
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return false;
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}
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void llvm::narrowShuffleMaskElts(int Scale, ArrayRef<int> Mask,
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SmallVectorImpl<int> &ScaledMask) {
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assert(Scale > 0 && "Unexpected scaling factor");
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// Fast-path: if no scaling, then it is just a copy.
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if (Scale == 1) {
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ScaledMask.assign(Mask.begin(), Mask.end());
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return;
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}
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ScaledMask.clear();
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for (int MaskElt : Mask) {
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if (MaskElt >= 0) {
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assert(((uint64_t)Scale * MaskElt + (Scale - 1)) <= INT32_MAX &&
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"Overflowed 32-bits");
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}
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for (int SliceElt = 0; SliceElt != Scale; ++SliceElt)
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ScaledMask.push_back(MaskElt < 0 ? MaskElt : Scale * MaskElt + SliceElt);
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}
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}
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bool llvm::widenShuffleMaskElts(int Scale, ArrayRef<int> Mask,
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SmallVectorImpl<int> &ScaledMask) {
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assert(Scale > 0 && "Unexpected scaling factor");
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// Fast-path: if no scaling, then it is just a copy.
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if (Scale == 1) {
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ScaledMask.assign(Mask.begin(), Mask.end());
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return true;
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}
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// We must map the original elements down evenly to a type with less elements.
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int NumElts = Mask.size();
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if (NumElts % Scale != 0)
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return false;
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ScaledMask.clear();
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ScaledMask.reserve(NumElts / Scale);
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// Step through the input mask by splitting into Scale-sized slices.
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do {
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ArrayRef<int> MaskSlice = Mask.take_front(Scale);
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assert((int)MaskSlice.size() == Scale && "Expected Scale-sized slice.");
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// The first element of the slice determines how we evaluate this slice.
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int SliceFront = MaskSlice.front();
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if (SliceFront < 0) {
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// Negative values (undef or other "sentinel" values) must be equal across
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// the entire slice.
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if (!is_splat(MaskSlice))
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return false;
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ScaledMask.push_back(SliceFront);
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} else {
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// A positive mask element must be cleanly divisible.
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if (SliceFront % Scale != 0)
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return false;
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// Elements of the slice must be consecutive.
|
|
for (int i = 1; i < Scale; ++i)
|
|
if (MaskSlice[i] != SliceFront + i)
|
|
return false;
|
|
ScaledMask.push_back(SliceFront / Scale);
|
|
}
|
|
Mask = Mask.drop_front(Scale);
|
|
} while (!Mask.empty());
|
|
|
|
assert((int)ScaledMask.size() * Scale == NumElts && "Unexpected scaled mask");
|
|
|
|
// All elements of the original mask can be scaled down to map to the elements
|
|
// of a mask with wider elements.
|
|
return true;
|
|
}
|
|
|
|
MapVector<Instruction *, uint64_t>
|
|
llvm::computeMinimumValueSizes(ArrayRef<BasicBlock *> Blocks, DemandedBits &DB,
|
|
const TargetTransformInfo *TTI) {
|
|
|
|
// DemandedBits will give us every value's live-out bits. But we want
|
|
// to ensure no extra casts would need to be inserted, so every DAG
|
|
// of connected values must have the same minimum bitwidth.
|
|
EquivalenceClasses<Value *> ECs;
|
|
SmallVector<Value *, 16> Worklist;
|
|
SmallPtrSet<Value *, 4> Roots;
|
|
SmallPtrSet<Value *, 16> Visited;
|
|
DenseMap<Value *, uint64_t> DBits;
|
|
SmallPtrSet<Instruction *, 4> InstructionSet;
|
|
MapVector<Instruction *, uint64_t> MinBWs;
|
|
|
|
// Determine the roots. We work bottom-up, from truncs or icmps.
|
|
bool SeenExtFromIllegalType = false;
|
|
for (auto *BB : Blocks)
|
|
for (auto &I : *BB) {
|
|
InstructionSet.insert(&I);
|
|
|
|
if (TTI && (isa<ZExtInst>(&I) || isa<SExtInst>(&I)) &&
|
|
!TTI->isTypeLegal(I.getOperand(0)->getType()))
|
|
SeenExtFromIllegalType = true;
|
|
|
|
// Only deal with non-vector integers up to 64-bits wide.
|
|
if ((isa<TruncInst>(&I) || isa<ICmpInst>(&I)) &&
|
|
!I.getType()->isVectorTy() &&
|
|
I.getOperand(0)->getType()->getScalarSizeInBits() <= 64) {
|
|
// Don't make work for ourselves. If we know the loaded type is legal,
|
|
// don't add it to the worklist.
|
|
if (TTI && isa<TruncInst>(&I) && TTI->isTypeLegal(I.getType()))
|
|
continue;
|
|
|
|
Worklist.push_back(&I);
|
|
Roots.insert(&I);
|
|
}
|
|
}
|
|
// Early exit.
|
|
if (Worklist.empty() || (TTI && !SeenExtFromIllegalType))
|
|
return MinBWs;
|
|
|
|
// Now proceed breadth-first, unioning values together.
|
|
while (!Worklist.empty()) {
|
|
Value *Val = Worklist.pop_back_val();
|
|
Value *Leader = ECs.getOrInsertLeaderValue(Val);
|
|
|
|
if (Visited.count(Val))
|
|
continue;
|
|
Visited.insert(Val);
|
|
|
|
// Non-instructions terminate a chain successfully.
|
|
if (!isa<Instruction>(Val))
|
|
continue;
|
|
Instruction *I = cast<Instruction>(Val);
|
|
|
|
// If we encounter a type that is larger than 64 bits, we can't represent
|
|
// it so bail out.
|
|
if (DB.getDemandedBits(I).getBitWidth() > 64)
|
|
return MapVector<Instruction *, uint64_t>();
|
|
|
|
uint64_t V = DB.getDemandedBits(I).getZExtValue();
|
|
DBits[Leader] |= V;
|
|
DBits[I] = V;
|
|
|
|
// Casts, loads and instructions outside of our range terminate a chain
|
|
// successfully.
|
|
if (isa<SExtInst>(I) || isa<ZExtInst>(I) || isa<LoadInst>(I) ||
|
|
!InstructionSet.count(I))
|
|
continue;
|
|
|
|
// Unsafe casts terminate a chain unsuccessfully. We can't do anything
|
|
// useful with bitcasts, ptrtoints or inttoptrs and it'd be unsafe to
|
|
// transform anything that relies on them.
|
|
if (isa<BitCastInst>(I) || isa<PtrToIntInst>(I) || isa<IntToPtrInst>(I) ||
|
|
!I->getType()->isIntegerTy()) {
|
|
DBits[Leader] |= ~0ULL;
|
|
continue;
|
|
}
|
|
|
|
// We don't modify the types of PHIs. Reductions will already have been
|
|
// truncated if possible, and inductions' sizes will have been chosen by
|
|
// indvars.
|
|
if (isa<PHINode>(I))
|
|
continue;
|
|
|
|
if (DBits[Leader] == ~0ULL)
|
|
// All bits demanded, no point continuing.
|
|
continue;
|
|
|
|
for (Value *O : cast<User>(I)->operands()) {
|
|
ECs.unionSets(Leader, O);
|
|
Worklist.push_back(O);
|
|
}
|
|
}
|
|
|
|
// Now we've discovered all values, walk them to see if there are
|
|
// any users we didn't see. If there are, we can't optimize that
|
|
// chain.
|
|
for (auto &I : DBits)
|
|
for (auto *U : I.first->users())
|
|
if (U->getType()->isIntegerTy() && DBits.count(U) == 0)
|
|
DBits[ECs.getOrInsertLeaderValue(I.first)] |= ~0ULL;
|
|
|
|
for (auto I = ECs.begin(), E = ECs.end(); I != E; ++I) {
|
|
uint64_t LeaderDemandedBits = 0;
|
|
for (Value *M : llvm::make_range(ECs.member_begin(I), ECs.member_end()))
|
|
LeaderDemandedBits |= DBits[M];
|
|
|
|
uint64_t MinBW = (sizeof(LeaderDemandedBits) * 8) -
|
|
llvm::countLeadingZeros(LeaderDemandedBits);
|
|
// Round up to a power of 2
|
|
if (!isPowerOf2_64((uint64_t)MinBW))
|
|
MinBW = NextPowerOf2(MinBW);
|
|
|
|
// We don't modify the types of PHIs. Reductions will already have been
|
|
// truncated if possible, and inductions' sizes will have been chosen by
|
|
// indvars.
|
|
// If we are required to shrink a PHI, abandon this entire equivalence class.
|
|
bool Abort = false;
|
|
for (Value *M : llvm::make_range(ECs.member_begin(I), ECs.member_end()))
|
|
if (isa<PHINode>(M) && MinBW < M->getType()->getScalarSizeInBits()) {
|
|
Abort = true;
|
|
break;
|
|
}
|
|
if (Abort)
|
|
continue;
|
|
|
|
for (Value *M : llvm::make_range(ECs.member_begin(I), ECs.member_end())) {
|
|
if (!isa<Instruction>(M))
|
|
continue;
|
|
Type *Ty = M->getType();
|
|
if (Roots.count(M))
|
|
Ty = cast<Instruction>(M)->getOperand(0)->getType();
|
|
if (MinBW < Ty->getScalarSizeInBits())
|
|
MinBWs[cast<Instruction>(M)] = MinBW;
|
|
}
|
|
}
|
|
|
|
return MinBWs;
|
|
}
|
|
|
|
/// Add all access groups in @p AccGroups to @p List.
|
|
template <typename ListT>
|
|
static void addToAccessGroupList(ListT &List, MDNode *AccGroups) {
|
|
// Interpret an access group as a list containing itself.
|
|
if (AccGroups->getNumOperands() == 0) {
|
|
assert(isValidAsAccessGroup(AccGroups) && "Node must be an access group");
|
|
List.insert(AccGroups);
|
|
return;
|
|
}
|
|
|
|
for (auto &AccGroupListOp : AccGroups->operands()) {
|
|
auto *Item = cast<MDNode>(AccGroupListOp.get());
|
|
assert(isValidAsAccessGroup(Item) && "List item must be an access group");
|
|
List.insert(Item);
|
|
}
|
|
}
|
|
|
|
MDNode *llvm::uniteAccessGroups(MDNode *AccGroups1, MDNode *AccGroups2) {
|
|
if (!AccGroups1)
|
|
return AccGroups2;
|
|
if (!AccGroups2)
|
|
return AccGroups1;
|
|
if (AccGroups1 == AccGroups2)
|
|
return AccGroups1;
|
|
|
|
SmallSetVector<Metadata *, 4> Union;
|
|
addToAccessGroupList(Union, AccGroups1);
|
|
addToAccessGroupList(Union, AccGroups2);
|
|
|
|
if (Union.size() == 0)
|
|
return nullptr;
|
|
if (Union.size() == 1)
|
|
return cast<MDNode>(Union.front());
|
|
|
|
LLVMContext &Ctx = AccGroups1->getContext();
|
|
return MDNode::get(Ctx, Union.getArrayRef());
|
|
}
|
|
|
|
MDNode *llvm::intersectAccessGroups(const Instruction *Inst1,
|
|
const Instruction *Inst2) {
|
|
bool MayAccessMem1 = Inst1->mayReadOrWriteMemory();
|
|
bool MayAccessMem2 = Inst2->mayReadOrWriteMemory();
|
|
|
|
if (!MayAccessMem1 && !MayAccessMem2)
|
|
return nullptr;
|
|
if (!MayAccessMem1)
|
|
return Inst2->getMetadata(LLVMContext::MD_access_group);
|
|
if (!MayAccessMem2)
|
|
return Inst1->getMetadata(LLVMContext::MD_access_group);
|
|
|
|
MDNode *MD1 = Inst1->getMetadata(LLVMContext::MD_access_group);
|
|
MDNode *MD2 = Inst2->getMetadata(LLVMContext::MD_access_group);
|
|
if (!MD1 || !MD2)
|
|
return nullptr;
|
|
if (MD1 == MD2)
|
|
return MD1;
|
|
|
|
// Use set for scalable 'contains' check.
|
|
SmallPtrSet<Metadata *, 4> AccGroupSet2;
|
|
addToAccessGroupList(AccGroupSet2, MD2);
|
|
|
|
SmallVector<Metadata *, 4> Intersection;
|
|
if (MD1->getNumOperands() == 0) {
|
|
assert(isValidAsAccessGroup(MD1) && "Node must be an access group");
|
|
if (AccGroupSet2.count(MD1))
|
|
Intersection.push_back(MD1);
|
|
} else {
|
|
for (const MDOperand &Node : MD1->operands()) {
|
|
auto *Item = cast<MDNode>(Node.get());
|
|
assert(isValidAsAccessGroup(Item) && "List item must be an access group");
|
|
if (AccGroupSet2.count(Item))
|
|
Intersection.push_back(Item);
|
|
}
|
|
}
|
|
|
|
if (Intersection.size() == 0)
|
|
return nullptr;
|
|
if (Intersection.size() == 1)
|
|
return cast<MDNode>(Intersection.front());
|
|
|
|
LLVMContext &Ctx = Inst1->getContext();
|
|
return MDNode::get(Ctx, Intersection);
|
|
}
|
|
|
|
/// \returns \p I after propagating metadata from \p VL.
|
|
Instruction *llvm::propagateMetadata(Instruction *Inst, ArrayRef<Value *> VL) {
|
|
if (VL.empty())
|
|
return Inst;
|
|
Instruction *I0 = cast<Instruction>(VL[0]);
|
|
SmallVector<std::pair<unsigned, MDNode *>, 4> Metadata;
|
|
I0->getAllMetadataOtherThanDebugLoc(Metadata);
|
|
|
|
for (auto Kind : {LLVMContext::MD_tbaa, LLVMContext::MD_alias_scope,
|
|
LLVMContext::MD_noalias, LLVMContext::MD_fpmath,
|
|
LLVMContext::MD_nontemporal, LLVMContext::MD_invariant_load,
|
|
LLVMContext::MD_access_group}) {
|
|
MDNode *MD = I0->getMetadata(Kind);
|
|
|
|
for (int J = 1, E = VL.size(); MD && J != E; ++J) {
|
|
const Instruction *IJ = cast<Instruction>(VL[J]);
|
|
MDNode *IMD = IJ->getMetadata(Kind);
|
|
switch (Kind) {
|
|
case LLVMContext::MD_tbaa:
|
|
MD = MDNode::getMostGenericTBAA(MD, IMD);
|
|
break;
|
|
case LLVMContext::MD_alias_scope:
|
|
MD = MDNode::getMostGenericAliasScope(MD, IMD);
|
|
break;
|
|
case LLVMContext::MD_fpmath:
|
|
MD = MDNode::getMostGenericFPMath(MD, IMD);
|
|
break;
|
|
case LLVMContext::MD_noalias:
|
|
case LLVMContext::MD_nontemporal:
|
|
case LLVMContext::MD_invariant_load:
|
|
MD = MDNode::intersect(MD, IMD);
|
|
break;
|
|
case LLVMContext::MD_access_group:
|
|
MD = intersectAccessGroups(Inst, IJ);
|
|
break;
|
|
default:
|
|
llvm_unreachable("unhandled metadata");
|
|
}
|
|
}
|
|
|
|
Inst->setMetadata(Kind, MD);
|
|
}
|
|
|
|
return Inst;
|
|
}
|
|
|
|
Constant *
|
|
llvm::createBitMaskForGaps(IRBuilderBase &Builder, unsigned VF,
|
|
const InterleaveGroup<Instruction> &Group) {
|
|
// All 1's means mask is not needed.
|
|
if (Group.getNumMembers() == Group.getFactor())
|
|
return nullptr;
|
|
|
|
// TODO: support reversed access.
|
|
assert(!Group.isReverse() && "Reversed group not supported.");
|
|
|
|
SmallVector<Constant *, 16> Mask;
|
|
for (unsigned i = 0; i < VF; i++)
|
|
for (unsigned j = 0; j < Group.getFactor(); ++j) {
|
|
unsigned HasMember = Group.getMember(j) ? 1 : 0;
|
|
Mask.push_back(Builder.getInt1(HasMember));
|
|
}
|
|
|
|
return ConstantVector::get(Mask);
|
|
}
|
|
|
|
llvm::SmallVector<int, 16>
|
|
llvm::createReplicatedMask(unsigned ReplicationFactor, unsigned VF) {
|
|
SmallVector<int, 16> MaskVec;
|
|
for (unsigned i = 0; i < VF; i++)
|
|
for (unsigned j = 0; j < ReplicationFactor; j++)
|
|
MaskVec.push_back(i);
|
|
|
|
return MaskVec;
|
|
}
|
|
|
|
llvm::SmallVector<int, 16> llvm::createInterleaveMask(unsigned VF,
|
|
unsigned NumVecs) {
|
|
SmallVector<int, 16> Mask;
|
|
for (unsigned i = 0; i < VF; i++)
|
|
for (unsigned j = 0; j < NumVecs; j++)
|
|
Mask.push_back(j * VF + i);
|
|
|
|
return Mask;
|
|
}
|
|
|
|
llvm::SmallVector<int, 16>
|
|
llvm::createStrideMask(unsigned Start, unsigned Stride, unsigned VF) {
|
|
SmallVector<int, 16> Mask;
|
|
for (unsigned i = 0; i < VF; i++)
|
|
Mask.push_back(Start + i * Stride);
|
|
|
|
return Mask;
|
|
}
|
|
|
|
llvm::SmallVector<int, 16> llvm::createSequentialMask(unsigned Start,
|
|
unsigned NumInts,
|
|
unsigned NumUndefs) {
|
|
SmallVector<int, 16> Mask;
|
|
for (unsigned i = 0; i < NumInts; i++)
|
|
Mask.push_back(Start + i);
|
|
|
|
for (unsigned i = 0; i < NumUndefs; i++)
|
|
Mask.push_back(-1);
|
|
|
|
return Mask;
|
|
}
|
|
|
|
/// A helper function for concatenating vectors. This function concatenates two
|
|
/// vectors having the same element type. If the second vector has fewer
|
|
/// elements than the first, it is padded with undefs.
|
|
static Value *concatenateTwoVectors(IRBuilderBase &Builder, Value *V1,
|
|
Value *V2) {
|
|
VectorType *VecTy1 = dyn_cast<VectorType>(V1->getType());
|
|
VectorType *VecTy2 = dyn_cast<VectorType>(V2->getType());
|
|
assert(VecTy1 && VecTy2 &&
|
|
VecTy1->getScalarType() == VecTy2->getScalarType() &&
|
|
"Expect two vectors with the same element type");
|
|
|
|
unsigned NumElts1 = cast<FixedVectorType>(VecTy1)->getNumElements();
|
|
unsigned NumElts2 = cast<FixedVectorType>(VecTy2)->getNumElements();
|
|
assert(NumElts1 >= NumElts2 && "Unexpect the first vector has less elements");
|
|
|
|
if (NumElts1 > NumElts2) {
|
|
// Extend with UNDEFs.
|
|
V2 = Builder.CreateShuffleVector(
|
|
V2, createSequentialMask(0, NumElts2, NumElts1 - NumElts2));
|
|
}
|
|
|
|
return Builder.CreateShuffleVector(
|
|
V1, V2, createSequentialMask(0, NumElts1 + NumElts2, 0));
|
|
}
|
|
|
|
Value *llvm::concatenateVectors(IRBuilderBase &Builder,
|
|
ArrayRef<Value *> Vecs) {
|
|
unsigned NumVecs = Vecs.size();
|
|
assert(NumVecs > 1 && "Should be at least two vectors");
|
|
|
|
SmallVector<Value *, 8> ResList;
|
|
ResList.append(Vecs.begin(), Vecs.end());
|
|
do {
|
|
SmallVector<Value *, 8> TmpList;
|
|
for (unsigned i = 0; i < NumVecs - 1; i += 2) {
|
|
Value *V0 = ResList[i], *V1 = ResList[i + 1];
|
|
assert((V0->getType() == V1->getType() || i == NumVecs - 2) &&
|
|
"Only the last vector may have a different type");
|
|
|
|
TmpList.push_back(concatenateTwoVectors(Builder, V0, V1));
|
|
}
|
|
|
|
// Push the last vector if the total number of vectors is odd.
|
|
if (NumVecs % 2 != 0)
|
|
TmpList.push_back(ResList[NumVecs - 1]);
|
|
|
|
ResList = TmpList;
|
|
NumVecs = ResList.size();
|
|
} while (NumVecs > 1);
|
|
|
|
return ResList[0];
|
|
}
|
|
|
|
bool llvm::maskIsAllZeroOrUndef(Value *Mask) {
|
|
assert(isa<VectorType>(Mask->getType()) &&
|
|
isa<IntegerType>(Mask->getType()->getScalarType()) &&
|
|
cast<IntegerType>(Mask->getType()->getScalarType())->getBitWidth() ==
|
|
1 &&
|
|
"Mask must be a vector of i1");
|
|
|
|
auto *ConstMask = dyn_cast<Constant>(Mask);
|
|
if (!ConstMask)
|
|
return false;
|
|
if (ConstMask->isNullValue() || isa<UndefValue>(ConstMask))
|
|
return true;
|
|
if (isa<ScalableVectorType>(ConstMask->getType()))
|
|
return false;
|
|
for (unsigned
|
|
I = 0,
|
|
E = cast<FixedVectorType>(ConstMask->getType())->getNumElements();
|
|
I != E; ++I) {
|
|
if (auto *MaskElt = ConstMask->getAggregateElement(I))
|
|
if (MaskElt->isNullValue() || isa<UndefValue>(MaskElt))
|
|
continue;
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
bool llvm::maskIsAllOneOrUndef(Value *Mask) {
|
|
assert(isa<VectorType>(Mask->getType()) &&
|
|
isa<IntegerType>(Mask->getType()->getScalarType()) &&
|
|
cast<IntegerType>(Mask->getType()->getScalarType())->getBitWidth() ==
|
|
1 &&
|
|
"Mask must be a vector of i1");
|
|
|
|
auto *ConstMask = dyn_cast<Constant>(Mask);
|
|
if (!ConstMask)
|
|
return false;
|
|
if (ConstMask->isAllOnesValue() || isa<UndefValue>(ConstMask))
|
|
return true;
|
|
if (isa<ScalableVectorType>(ConstMask->getType()))
|
|
return false;
|
|
for (unsigned
|
|
I = 0,
|
|
E = cast<FixedVectorType>(ConstMask->getType())->getNumElements();
|
|
I != E; ++I) {
|
|
if (auto *MaskElt = ConstMask->getAggregateElement(I))
|
|
if (MaskElt->isAllOnesValue() || isa<UndefValue>(MaskElt))
|
|
continue;
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/// TODO: This is a lot like known bits, but for
|
|
/// vectors. Is there something we can common this with?
|
|
APInt llvm::possiblyDemandedEltsInMask(Value *Mask) {
|
|
assert(isa<FixedVectorType>(Mask->getType()) &&
|
|
isa<IntegerType>(Mask->getType()->getScalarType()) &&
|
|
cast<IntegerType>(Mask->getType()->getScalarType())->getBitWidth() ==
|
|
1 &&
|
|
"Mask must be a fixed width vector of i1");
|
|
|
|
const unsigned VWidth =
|
|
cast<FixedVectorType>(Mask->getType())->getNumElements();
|
|
APInt DemandedElts = APInt::getAllOnes(VWidth);
|
|
if (auto *CV = dyn_cast<ConstantVector>(Mask))
|
|
for (unsigned i = 0; i < VWidth; i++)
|
|
if (CV->getAggregateElement(i)->isNullValue())
|
|
DemandedElts.clearBit(i);
|
|
return DemandedElts;
|
|
}
|
|
|
|
bool InterleavedAccessInfo::isStrided(int Stride) {
|
|
unsigned Factor = std::abs(Stride);
|
|
return Factor >= 2 && Factor <= MaxInterleaveGroupFactor;
|
|
}
|
|
|
|
void InterleavedAccessInfo::collectConstStrideAccesses(
|
|
MapVector<Instruction *, StrideDescriptor> &AccessStrideInfo,
|
|
const ValueToValueMap &Strides) {
|
|
auto &DL = TheLoop->getHeader()->getModule()->getDataLayout();
|
|
|
|
// Since it's desired that the load/store instructions be maintained in
|
|
// "program order" for the interleaved access analysis, we have to visit the
|
|
// blocks in the loop in reverse postorder (i.e., in a topological order).
|
|
// Such an ordering will ensure that any load/store that may be executed
|
|
// before a second load/store will precede the second load/store in
|
|
// AccessStrideInfo.
|
|
LoopBlocksDFS DFS(TheLoop);
|
|
DFS.perform(LI);
|
|
for (BasicBlock *BB : make_range(DFS.beginRPO(), DFS.endRPO()))
|
|
for (auto &I : *BB) {
|
|
Value *Ptr = getLoadStorePointerOperand(&I);
|
|
if (!Ptr)
|
|
continue;
|
|
Type *ElementTy = getLoadStoreType(&I);
|
|
|
|
// We don't check wrapping here because we don't know yet if Ptr will be
|
|
// part of a full group or a group with gaps. Checking wrapping for all
|
|
// pointers (even those that end up in groups with no gaps) will be overly
|
|
// conservative. For full groups, wrapping should be ok since if we would
|
|
// wrap around the address space we would do a memory access at nullptr
|
|
// even without the transformation. The wrapping checks are therefore
|
|
// deferred until after we've formed the interleaved groups.
|
|
int64_t Stride = getPtrStride(PSE, ElementTy, Ptr, TheLoop, Strides,
|
|
/*Assume=*/true, /*ShouldCheckWrap=*/false);
|
|
|
|
const SCEV *Scev = replaceSymbolicStrideSCEV(PSE, Strides, Ptr);
|
|
uint64_t Size = DL.getTypeAllocSize(ElementTy);
|
|
AccessStrideInfo[&I] = StrideDescriptor(Stride, Scev, Size,
|
|
getLoadStoreAlignment(&I));
|
|
}
|
|
}
|
|
|
|
// Analyze interleaved accesses and collect them into interleaved load and
|
|
// store groups.
|
|
//
|
|
// When generating code for an interleaved load group, we effectively hoist all
|
|
// loads in the group to the location of the first load in program order. When
|
|
// generating code for an interleaved store group, we sink all stores to the
|
|
// location of the last store. This code motion can change the order of load
|
|
// and store instructions and may break dependences.
|
|
//
|
|
// The code generation strategy mentioned above ensures that we won't violate
|
|
// any write-after-read (WAR) dependences.
|
|
//
|
|
// E.g., for the WAR dependence: a = A[i]; // (1)
|
|
// A[i] = b; // (2)
|
|
//
|
|
// The store group of (2) is always inserted at or below (2), and the load
|
|
// group of (1) is always inserted at or above (1). Thus, the instructions will
|
|
// never be reordered. All other dependences are checked to ensure the
|
|
// correctness of the instruction reordering.
|
|
//
|
|
// The algorithm visits all memory accesses in the loop in bottom-up program
|
|
// order. Program order is established by traversing the blocks in the loop in
|
|
// reverse postorder when collecting the accesses.
|
|
//
|
|
// We visit the memory accesses in bottom-up order because it can simplify the
|
|
// construction of store groups in the presence of write-after-write (WAW)
|
|
// dependences.
|
|
//
|
|
// E.g., for the WAW dependence: A[i] = a; // (1)
|
|
// A[i] = b; // (2)
|
|
// A[i + 1] = c; // (3)
|
|
//
|
|
// We will first create a store group with (3) and (2). (1) can't be added to
|
|
// this group because it and (2) are dependent. However, (1) can be grouped
|
|
// with other accesses that may precede it in program order. Note that a
|
|
// bottom-up order does not imply that WAW dependences should not be checked.
|
|
void InterleavedAccessInfo::analyzeInterleaving(
|
|
bool EnablePredicatedInterleavedMemAccesses) {
|
|
LLVM_DEBUG(dbgs() << "LV: Analyzing interleaved accesses...\n");
|
|
const ValueToValueMap &Strides = LAI->getSymbolicStrides();
|
|
|
|
// Holds all accesses with a constant stride.
|
|
MapVector<Instruction *, StrideDescriptor> AccessStrideInfo;
|
|
collectConstStrideAccesses(AccessStrideInfo, Strides);
|
|
|
|
if (AccessStrideInfo.empty())
|
|
return;
|
|
|
|
// Collect the dependences in the loop.
|
|
collectDependences();
|
|
|
|
// Holds all interleaved store groups temporarily.
|
|
SmallSetVector<InterleaveGroup<Instruction> *, 4> StoreGroups;
|
|
// Holds all interleaved load groups temporarily.
|
|
SmallSetVector<InterleaveGroup<Instruction> *, 4> LoadGroups;
|
|
|
|
// Search in bottom-up program order for pairs of accesses (A and B) that can
|
|
// form interleaved load or store groups. In the algorithm below, access A
|
|
// precedes access B in program order. We initialize a group for B in the
|
|
// outer loop of the algorithm, and then in the inner loop, we attempt to
|
|
// insert each A into B's group if:
|
|
//
|
|
// 1. A and B have the same stride,
|
|
// 2. A and B have the same memory object size, and
|
|
// 3. A belongs in B's group according to its distance from B.
|
|
//
|
|
// Special care is taken to ensure group formation will not break any
|
|
// dependences.
|
|
for (auto BI = AccessStrideInfo.rbegin(), E = AccessStrideInfo.rend();
|
|
BI != E; ++BI) {
|
|
Instruction *B = BI->first;
|
|
StrideDescriptor DesB = BI->second;
|
|
|
|
// Initialize a group for B if it has an allowable stride. Even if we don't
|
|
// create a group for B, we continue with the bottom-up algorithm to ensure
|
|
// we don't break any of B's dependences.
|
|
InterleaveGroup<Instruction> *Group = nullptr;
|
|
if (isStrided(DesB.Stride) &&
|
|
(!isPredicated(B->getParent()) || EnablePredicatedInterleavedMemAccesses)) {
|
|
Group = getInterleaveGroup(B);
|
|
if (!Group) {
|
|
LLVM_DEBUG(dbgs() << "LV: Creating an interleave group with:" << *B
|
|
<< '\n');
|
|
Group = createInterleaveGroup(B, DesB.Stride, DesB.Alignment);
|
|
}
|
|
if (B->mayWriteToMemory())
|
|
StoreGroups.insert(Group);
|
|
else
|
|
LoadGroups.insert(Group);
|
|
}
|
|
|
|
for (auto AI = std::next(BI); AI != E; ++AI) {
|
|
Instruction *A = AI->first;
|
|
StrideDescriptor DesA = AI->second;
|
|
|
|
// Our code motion strategy implies that we can't have dependences
|
|
// between accesses in an interleaved group and other accesses located
|
|
// between the first and last member of the group. Note that this also
|
|
// means that a group can't have more than one member at a given offset.
|
|
// The accesses in a group can have dependences with other accesses, but
|
|
// we must ensure we don't extend the boundaries of the group such that
|
|
// we encompass those dependent accesses.
|
|
//
|
|
// For example, assume we have the sequence of accesses shown below in a
|
|
// stride-2 loop:
|
|
//
|
|
// (1, 2) is a group | A[i] = a; // (1)
|
|
// | A[i-1] = b; // (2) |
|
|
// A[i-3] = c; // (3)
|
|
// A[i] = d; // (4) | (2, 4) is not a group
|
|
//
|
|
// Because accesses (2) and (3) are dependent, we can group (2) with (1)
|
|
// but not with (4). If we did, the dependent access (3) would be within
|
|
// the boundaries of the (2, 4) group.
|
|
if (!canReorderMemAccessesForInterleavedGroups(&*AI, &*BI)) {
|
|
// If a dependence exists and A is already in a group, we know that A
|
|
// must be a store since A precedes B and WAR dependences are allowed.
|
|
// Thus, A would be sunk below B. We release A's group to prevent this
|
|
// illegal code motion. A will then be free to form another group with
|
|
// instructions that precede it.
|
|
if (isInterleaved(A)) {
|
|
InterleaveGroup<Instruction> *StoreGroup = getInterleaveGroup(A);
|
|
|
|
LLVM_DEBUG(dbgs() << "LV: Invalidated store group due to "
|
|
"dependence between " << *A << " and "<< *B << '\n');
|
|
|
|
StoreGroups.remove(StoreGroup);
|
|
releaseGroup(StoreGroup);
|
|
}
|
|
|
|
// If a dependence exists and A is not already in a group (or it was
|
|
// and we just released it), B might be hoisted above A (if B is a
|
|
// load) or another store might be sunk below A (if B is a store). In
|
|
// either case, we can't add additional instructions to B's group. B
|
|
// will only form a group with instructions that it precedes.
|
|
break;
|
|
}
|
|
|
|
// At this point, we've checked for illegal code motion. If either A or B
|
|
// isn't strided, there's nothing left to do.
|
|
if (!isStrided(DesA.Stride) || !isStrided(DesB.Stride))
|
|
continue;
|
|
|
|
// Ignore A if it's already in a group or isn't the same kind of memory
|
|
// operation as B.
|
|
// Note that mayReadFromMemory() isn't mutually exclusive to
|
|
// mayWriteToMemory in the case of atomic loads. We shouldn't see those
|
|
// here, canVectorizeMemory() should have returned false - except for the
|
|
// case we asked for optimization remarks.
|
|
if (isInterleaved(A) ||
|
|
(A->mayReadFromMemory() != B->mayReadFromMemory()) ||
|
|
(A->mayWriteToMemory() != B->mayWriteToMemory()))
|
|
continue;
|
|
|
|
// Check rules 1 and 2. Ignore A if its stride or size is different from
|
|
// that of B.
|
|
if (DesA.Stride != DesB.Stride || DesA.Size != DesB.Size)
|
|
continue;
|
|
|
|
// Ignore A if the memory object of A and B don't belong to the same
|
|
// address space
|
|
if (getLoadStoreAddressSpace(A) != getLoadStoreAddressSpace(B))
|
|
continue;
|
|
|
|
// Calculate the distance from A to B.
|
|
const SCEVConstant *DistToB = dyn_cast<SCEVConstant>(
|
|
PSE.getSE()->getMinusSCEV(DesA.Scev, DesB.Scev));
|
|
if (!DistToB)
|
|
continue;
|
|
int64_t DistanceToB = DistToB->getAPInt().getSExtValue();
|
|
|
|
// Check rule 3. Ignore A if its distance to B is not a multiple of the
|
|
// size.
|
|
if (DistanceToB % static_cast<int64_t>(DesB.Size))
|
|
continue;
|
|
|
|
// All members of a predicated interleave-group must have the same predicate,
|
|
// and currently must reside in the same BB.
|
|
BasicBlock *BlockA = A->getParent();
|
|
BasicBlock *BlockB = B->getParent();
|
|
if ((isPredicated(BlockA) || isPredicated(BlockB)) &&
|
|
(!EnablePredicatedInterleavedMemAccesses || BlockA != BlockB))
|
|
continue;
|
|
|
|
// The index of A is the index of B plus A's distance to B in multiples
|
|
// of the size.
|
|
int IndexA =
|
|
Group->getIndex(B) + DistanceToB / static_cast<int64_t>(DesB.Size);
|
|
|
|
// Try to insert A into B's group.
|
|
if (Group->insertMember(A, IndexA, DesA.Alignment)) {
|
|
LLVM_DEBUG(dbgs() << "LV: Inserted:" << *A << '\n'
|
|
<< " into the interleave group with" << *B
|
|
<< '\n');
|
|
InterleaveGroupMap[A] = Group;
|
|
|
|
// Set the first load in program order as the insert position.
|
|
if (A->mayReadFromMemory())
|
|
Group->setInsertPos(A);
|
|
}
|
|
} // Iteration over A accesses.
|
|
} // Iteration over B accesses.
|
|
|
|
auto InvalidateGroupIfMemberMayWrap = [&](InterleaveGroup<Instruction> *Group,
|
|
int Index,
|
|
std::string FirstOrLast) -> bool {
|
|
Instruction *Member = Group->getMember(Index);
|
|
assert(Member && "Group member does not exist");
|
|
Value *MemberPtr = getLoadStorePointerOperand(Member);
|
|
Type *AccessTy = getLoadStoreType(Member);
|
|
if (getPtrStride(PSE, AccessTy, MemberPtr, TheLoop, Strides,
|
|
/*Assume=*/false, /*ShouldCheckWrap=*/true))
|
|
return false;
|
|
LLVM_DEBUG(dbgs() << "LV: Invalidate candidate interleaved group due to "
|
|
<< FirstOrLast
|
|
<< " group member potentially pointer-wrapping.\n");
|
|
releaseGroup(Group);
|
|
return true;
|
|
};
|
|
|
|
// Remove interleaved groups with gaps whose memory
|
|
// accesses may wrap around. We have to revisit the getPtrStride analysis,
|
|
// this time with ShouldCheckWrap=true, since collectConstStrideAccesses does
|
|
// not check wrapping (see documentation there).
|
|
// FORNOW we use Assume=false;
|
|
// TODO: Change to Assume=true but making sure we don't exceed the threshold
|
|
// of runtime SCEV assumptions checks (thereby potentially failing to
|
|
// vectorize altogether).
|
|
// Additional optional optimizations:
|
|
// TODO: If we are peeling the loop and we know that the first pointer doesn't
|
|
// wrap then we can deduce that all pointers in the group don't wrap.
|
|
// This means that we can forcefully peel the loop in order to only have to
|
|
// check the first pointer for no-wrap. When we'll change to use Assume=true
|
|
// we'll only need at most one runtime check per interleaved group.
|
|
for (auto *Group : LoadGroups) {
|
|
// Case 1: A full group. Can Skip the checks; For full groups, if the wide
|
|
// load would wrap around the address space we would do a memory access at
|
|
// nullptr even without the transformation.
|
|
if (Group->getNumMembers() == Group->getFactor())
|
|
continue;
|
|
|
|
// Case 2: If first and last members of the group don't wrap this implies
|
|
// that all the pointers in the group don't wrap.
|
|
// So we check only group member 0 (which is always guaranteed to exist),
|
|
// and group member Factor - 1; If the latter doesn't exist we rely on
|
|
// peeling (if it is a non-reversed accsess -- see Case 3).
|
|
if (InvalidateGroupIfMemberMayWrap(Group, 0, std::string("first")))
|
|
continue;
|
|
if (Group->getMember(Group->getFactor() - 1))
|
|
InvalidateGroupIfMemberMayWrap(Group, Group->getFactor() - 1,
|
|
std::string("last"));
|
|
else {
|
|
// Case 3: A non-reversed interleaved load group with gaps: We need
|
|
// to execute at least one scalar epilogue iteration. This will ensure
|
|
// we don't speculatively access memory out-of-bounds. We only need
|
|
// to look for a member at index factor - 1, since every group must have
|
|
// a member at index zero.
|
|
if (Group->isReverse()) {
|
|
LLVM_DEBUG(
|
|
dbgs() << "LV: Invalidate candidate interleaved group due to "
|
|
"a reverse access with gaps.\n");
|
|
releaseGroup(Group);
|
|
continue;
|
|
}
|
|
LLVM_DEBUG(
|
|
dbgs() << "LV: Interleaved group requires epilogue iteration.\n");
|
|
RequiresScalarEpilogue = true;
|
|
}
|
|
}
|
|
|
|
for (auto *Group : StoreGroups) {
|
|
// Case 1: A full group. Can Skip the checks; For full groups, if the wide
|
|
// store would wrap around the address space we would do a memory access at
|
|
// nullptr even without the transformation.
|
|
if (Group->getNumMembers() == Group->getFactor())
|
|
continue;
|
|
|
|
// Interleave-store-group with gaps is implemented using masked wide store.
|
|
// Remove interleaved store groups with gaps if
|
|
// masked-interleaved-accesses are not enabled by the target.
|
|
if (!EnablePredicatedInterleavedMemAccesses) {
|
|
LLVM_DEBUG(
|
|
dbgs() << "LV: Invalidate candidate interleaved store group due "
|
|
"to gaps.\n");
|
|
releaseGroup(Group);
|
|
continue;
|
|
}
|
|
|
|
// Case 2: If first and last members of the group don't wrap this implies
|
|
// that all the pointers in the group don't wrap.
|
|
// So we check only group member 0 (which is always guaranteed to exist),
|
|
// and the last group member. Case 3 (scalar epilog) is not relevant for
|
|
// stores with gaps, which are implemented with masked-store (rather than
|
|
// speculative access, as in loads).
|
|
if (InvalidateGroupIfMemberMayWrap(Group, 0, std::string("first")))
|
|
continue;
|
|
for (int Index = Group->getFactor() - 1; Index > 0; Index--)
|
|
if (Group->getMember(Index)) {
|
|
InvalidateGroupIfMemberMayWrap(Group, Index, std::string("last"));
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void InterleavedAccessInfo::invalidateGroupsRequiringScalarEpilogue() {
|
|
// If no group had triggered the requirement to create an epilogue loop,
|
|
// there is nothing to do.
|
|
if (!requiresScalarEpilogue())
|
|
return;
|
|
|
|
bool ReleasedGroup = false;
|
|
// Release groups requiring scalar epilogues. Note that this also removes them
|
|
// from InterleaveGroups.
|
|
for (auto *Group : make_early_inc_range(InterleaveGroups)) {
|
|
if (!Group->requiresScalarEpilogue())
|
|
continue;
|
|
LLVM_DEBUG(
|
|
dbgs()
|
|
<< "LV: Invalidate candidate interleaved group due to gaps that "
|
|
"require a scalar epilogue (not allowed under optsize) and cannot "
|
|
"be masked (not enabled). \n");
|
|
releaseGroup(Group);
|
|
ReleasedGroup = true;
|
|
}
|
|
assert(ReleasedGroup && "At least one group must be invalidated, as a "
|
|
"scalar epilogue was required");
|
|
(void)ReleasedGroup;
|
|
RequiresScalarEpilogue = false;
|
|
}
|
|
|
|
template <typename InstT>
|
|
void InterleaveGroup<InstT>::addMetadata(InstT *NewInst) const {
|
|
llvm_unreachable("addMetadata can only be used for Instruction");
|
|
}
|
|
|
|
namespace llvm {
|
|
template <>
|
|
void InterleaveGroup<Instruction>::addMetadata(Instruction *NewInst) const {
|
|
SmallVector<Value *, 4> VL;
|
|
std::transform(Members.begin(), Members.end(), std::back_inserter(VL),
|
|
[](std::pair<int, Instruction *> p) { return p.second; });
|
|
propagateMetadata(NewInst, VL);
|
|
}
|
|
}
|
|
|
|
std::string VFABI::mangleTLIVectorName(StringRef VectorName,
|
|
StringRef ScalarName, unsigned numArgs,
|
|
ElementCount VF) {
|
|
SmallString<256> Buffer;
|
|
llvm::raw_svector_ostream Out(Buffer);
|
|
Out << "_ZGV" << VFABI::_LLVM_ << "N";
|
|
if (VF.isScalable())
|
|
Out << 'x';
|
|
else
|
|
Out << VF.getFixedValue();
|
|
for (unsigned I = 0; I < numArgs; ++I)
|
|
Out << "v";
|
|
Out << "_" << ScalarName << "(" << VectorName << ")";
|
|
return std::string(Out.str());
|
|
}
|
|
|
|
void VFABI::getVectorVariantNames(
|
|
const CallInst &CI, SmallVectorImpl<std::string> &VariantMappings) {
|
|
const StringRef S = CI.getFnAttr(VFABI::MappingsAttrName).getValueAsString();
|
|
if (S.empty())
|
|
return;
|
|
|
|
SmallVector<StringRef, 8> ListAttr;
|
|
S.split(ListAttr, ",");
|
|
|
|
for (auto &S : SetVector<StringRef>(ListAttr.begin(), ListAttr.end())) {
|
|
#ifndef NDEBUG
|
|
LLVM_DEBUG(dbgs() << "VFABI: adding mapping '" << S << "'\n");
|
|
Optional<VFInfo> Info = VFABI::tryDemangleForVFABI(S, *(CI.getModule()));
|
|
assert(Info.hasValue() && "Invalid name for a VFABI variant.");
|
|
assert(CI.getModule()->getFunction(Info.getValue().VectorName) &&
|
|
"Vector function is missing.");
|
|
#endif
|
|
VariantMappings.push_back(std::string(S));
|
|
}
|
|
}
|
|
|
|
bool VFShape::hasValidParameterList() const {
|
|
for (unsigned Pos = 0, NumParams = Parameters.size(); Pos < NumParams;
|
|
++Pos) {
|
|
assert(Parameters[Pos].ParamPos == Pos && "Broken parameter list.");
|
|
|
|
switch (Parameters[Pos].ParamKind) {
|
|
default: // Nothing to check.
|
|
break;
|
|
case VFParamKind::OMP_Linear:
|
|
case VFParamKind::OMP_LinearRef:
|
|
case VFParamKind::OMP_LinearVal:
|
|
case VFParamKind::OMP_LinearUVal:
|
|
// Compile time linear steps must be non-zero.
|
|
if (Parameters[Pos].LinearStepOrPos == 0)
|
|
return false;
|
|
break;
|
|
case VFParamKind::OMP_LinearPos:
|
|
case VFParamKind::OMP_LinearRefPos:
|
|
case VFParamKind::OMP_LinearValPos:
|
|
case VFParamKind::OMP_LinearUValPos:
|
|
// The runtime linear step must be referring to some other
|
|
// parameters in the signature.
|
|
if (Parameters[Pos].LinearStepOrPos >= int(NumParams))
|
|
return false;
|
|
// The linear step parameter must be marked as uniform.
|
|
if (Parameters[Parameters[Pos].LinearStepOrPos].ParamKind !=
|
|
VFParamKind::OMP_Uniform)
|
|
return false;
|
|
// The linear step parameter can't point at itself.
|
|
if (Parameters[Pos].LinearStepOrPos == int(Pos))
|
|
return false;
|
|
break;
|
|
case VFParamKind::GlobalPredicate:
|
|
// The global predicate must be the unique. Can be placed anywhere in the
|
|
// signature.
|
|
for (unsigned NextPos = Pos + 1; NextPos < NumParams; ++NextPos)
|
|
if (Parameters[NextPos].ParamKind == VFParamKind::GlobalPredicate)
|
|
return false;
|
|
break;
|
|
}
|
|
}
|
|
return true;
|
|
}
|