//===- VPlanUtils.cpp - VPlan-related utilities ---------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "VPlanUtils.h"
#include "VPlanPatternMatch.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"

using namespace llvm;

bool vputils::onlyFirstLaneUsed(const VPValue *Def) {
  return all_of(Def->users(),
                [Def](const VPUser *U) { return U->onlyFirstLaneUsed(Def); });
}

bool vputils::onlyFirstPartUsed(const VPValue *Def) {
  return all_of(Def->users(),
                [Def](const VPUser *U) { return U->onlyFirstPartUsed(Def); });
}

VPValue *vputils::getOrCreateVPValueForSCEVExpr(VPlan &Plan, const SCEV *Expr,
                                                ScalarEvolution &SE) {
  if (auto *Expanded = Plan.getSCEVExpansion(Expr))
    return Expanded;
  VPValue *Expanded = nullptr;
  if (auto *E = dyn_cast<SCEVConstant>(Expr))
    Expanded = Plan.getOrAddLiveIn(E->getValue());
  else if (auto *E = dyn_cast<SCEVUnknown>(Expr))
    Expanded = Plan.getOrAddLiveIn(E->getValue());
  else {
    Expanded = new VPExpandSCEVRecipe(Expr, SE);
    Plan.getPreheader()->appendRecipe(Expanded->getDefiningRecipe());
  }
  Plan.addSCEVExpansion(Expr, Expanded);
  return Expanded;
}

bool vputils::isHeaderMask(const VPValue *V, VPlan &Plan) {
  if (isa<VPActiveLaneMaskPHIRecipe>(V))
    return true;

  auto IsWideCanonicalIV = [](VPValue *A) {
    return isa<VPWidenCanonicalIVRecipe>(A) ||
           (isa<VPWidenIntOrFpInductionRecipe>(A) &&
            cast<VPWidenIntOrFpInductionRecipe>(A)->isCanonical());
  };

  VPValue *A, *B;
  using namespace VPlanPatternMatch;

  if (match(V, m_ActiveLaneMask(m_VPValue(A), m_VPValue(B))))
    return B == Plan.getTripCount() &&
           (match(A, m_ScalarIVSteps(m_CanonicalIV(), m_SpecificInt(1))) ||
            IsWideCanonicalIV(A));

  return match(V, m_Binary<Instruction::ICmp>(m_VPValue(A), m_VPValue(B))) &&
         IsWideCanonicalIV(A) && B == Plan.getOrCreateBackedgeTakenCount();
}