0d736e296c
Add a new getSCEVExprForVPValue utility which can be used to get a SCEV expression for a VPValue. The initial implementation only returns SCEVs for live-in IR values (by constructing a SCEV based on the live-in IR value) and VPExpandSCEVRecipe. This is enough to serve its first use, getting a SCEV for a VPlan's trip count, but will be extended in the future. It also removes createTripCountSCEV, as the new helper can be used to retrieve the SCEV from the VPlan. PR: https://github.com/llvm/llvm-project/pull/94464
75 lines
2.7 KiB
C++
75 lines
2.7 KiB
C++
//===- VPlanUtils.cpp - VPlan-related utilities ---------------------------===//
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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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#include "VPlanUtils.h"
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#include "VPlanPatternMatch.h"
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#include "llvm/ADT/TypeSwitch.h"
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#include "llvm/Analysis/ScalarEvolutionExpressions.h"
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using namespace llvm;
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bool vputils::onlyFirstLaneUsed(const VPValue *Def) {
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return all_of(Def->users(),
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[Def](const VPUser *U) { return U->onlyFirstLaneUsed(Def); });
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}
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bool vputils::onlyFirstPartUsed(const VPValue *Def) {
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return all_of(Def->users(),
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[Def](const VPUser *U) { return U->onlyFirstPartUsed(Def); });
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}
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VPValue *vputils::getOrCreateVPValueForSCEVExpr(VPlan &Plan, const SCEV *Expr,
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ScalarEvolution &SE) {
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if (auto *Expanded = Plan.getSCEVExpansion(Expr))
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return Expanded;
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VPValue *Expanded = nullptr;
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if (auto *E = dyn_cast<SCEVConstant>(Expr))
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Expanded = Plan.getOrAddLiveIn(E->getValue());
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else if (auto *E = dyn_cast<SCEVUnknown>(Expr))
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Expanded = Plan.getOrAddLiveIn(E->getValue());
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else {
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Expanded = new VPExpandSCEVRecipe(Expr, SE);
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Plan.getPreheader()->appendRecipe(Expanded->getDefiningRecipe());
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}
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Plan.addSCEVExpansion(Expr, Expanded);
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return Expanded;
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}
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bool vputils::isHeaderMask(const VPValue *V, VPlan &Plan) {
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if (isa<VPActiveLaneMaskPHIRecipe>(V))
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return true;
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auto IsWideCanonicalIV = [](VPValue *A) {
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return isa<VPWidenCanonicalIVRecipe>(A) ||
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(isa<VPWidenIntOrFpInductionRecipe>(A) &&
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cast<VPWidenIntOrFpInductionRecipe>(A)->isCanonical());
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};
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VPValue *A, *B;
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using namespace VPlanPatternMatch;
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if (match(V, m_ActiveLaneMask(m_VPValue(A), m_VPValue(B))))
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return B == Plan.getTripCount() &&
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(match(A, m_ScalarIVSteps(m_CanonicalIV(), m_SpecificInt(1))) ||
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IsWideCanonicalIV(A));
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return match(V, m_Binary<Instruction::ICmp>(m_VPValue(A), m_VPValue(B))) &&
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IsWideCanonicalIV(A) && B == Plan.getOrCreateBackedgeTakenCount();
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}
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const SCEV *vputils::getSCEVExprForVPValue(VPValue *V, ScalarEvolution &SE) {
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if (V->isLiveIn())
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return SE.getSCEV(V->getLiveInIRValue());
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// TODO: Support constructing SCEVs for more recipes as needed.
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return TypeSwitch<const VPRecipeBase *, const SCEV *>(V->getDefiningRecipe())
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.Case<VPExpandSCEVRecipe>(
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[](const VPExpandSCEVRecipe *R) { return R->getSCEV(); })
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.Default([&SE](const VPRecipeBase *) { return SE.getCouldNotCompute(); });
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}
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