llvm-project/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
Florian Hahn 15a74b64df
[VPlan] Manage pairs of incoming (VPValue, VPBB) in VPWidenPHIRecipe.
This patch extends VPWidenPHIRecipe to manage pairs of incoming
(VPValue, VPBasicBlock) in the VPlan native path. This is made possible
because we now directly manage defined VPValues for recipes.

By keeping both the incoming value and block in the recipe directly,
code-generation in the VPlan native path becomes independent of the
predecessor ordering when fixing up non-induction phis, which currently
can cause crashes in the VPlan native path.

This fixes PR45958.

Reviewed By: sguggill

Differential Revision: https://reviews.llvm.org/D96773
2021-02-22 09:44:25 +00:00

94 lines
3.8 KiB
C++

//===-- VPlanTransforms.cpp - Utility VPlan to VPlan transforms -----------===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file implements a set of utility VPlan to VPlan transformations.
///
//===----------------------------------------------------------------------===//
#include "VPlanTransforms.h"
#include "llvm/ADT/PostOrderIterator.h"
using namespace llvm;
void VPlanTransforms::VPInstructionsToVPRecipes(
Loop *OrigLoop, VPlanPtr &Plan,
LoopVectorizationLegality::InductionList &Inductions,
SmallPtrSetImpl<Instruction *> &DeadInstructions) {
auto *TopRegion = cast<VPRegionBlock>(Plan->getEntry());
ReversePostOrderTraversal<VPBlockBase *> RPOT(TopRegion->getEntry());
for (VPBlockBase *Base : RPOT) {
// Do not widen instructions in pre-header and exit blocks.
if (Base->getNumPredecessors() == 0 || Base->getNumSuccessors() == 0)
continue;
VPBasicBlock *VPBB = Base->getEntryBasicBlock();
// Introduce each ingredient into VPlan.
for (auto I = VPBB->begin(), E = VPBB->end(); I != E;) {
VPRecipeBase *Ingredient = &*I++;
VPValue *VPV = Ingredient->getVPValue();
Instruction *Inst = cast<Instruction>(VPV->getUnderlyingValue());
if (DeadInstructions.count(Inst)) {
VPValue DummyValue;
VPV->replaceAllUsesWith(&DummyValue);
Ingredient->eraseFromParent();
continue;
}
VPRecipeBase *NewRecipe = nullptr;
if (auto *VPPhi = dyn_cast<VPWidenPHIRecipe>(Ingredient)) {
auto *Phi = cast<PHINode>(VPPhi->getUnderlyingValue());
InductionDescriptor II = Inductions.lookup(Phi);
if (II.getKind() == InductionDescriptor::IK_IntInduction ||
II.getKind() == InductionDescriptor::IK_FpInduction) {
VPValue *Start = Plan->getOrAddVPValue(II.getStartValue());
NewRecipe = new VPWidenIntOrFpInductionRecipe(Phi, Start, nullptr);
} else {
Plan->addVPValue(Phi, VPPhi);
continue;
}
} else {
assert(isa<VPInstruction>(Ingredient) &&
"only VPInstructions expected here");
assert(!isa<PHINode>(Inst) && "phis should be handled above");
// Create VPWidenMemoryInstructionRecipe for loads and stores.
if (LoadInst *Load = dyn_cast<LoadInst>(Inst)) {
NewRecipe = new VPWidenMemoryInstructionRecipe(
*Load, Plan->getOrAddVPValue(getLoadStorePointerOperand(Inst)),
nullptr /*Mask*/);
} else if (StoreInst *Store = dyn_cast<StoreInst>(Inst)) {
NewRecipe = new VPWidenMemoryInstructionRecipe(
*Store, Plan->getOrAddVPValue(getLoadStorePointerOperand(Inst)),
Plan->getOrAddVPValue(Store->getValueOperand()),
nullptr /*Mask*/);
} else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
NewRecipe = new VPWidenGEPRecipe(
GEP, Plan->mapToVPValues(GEP->operands()), OrigLoop);
} else {
NewRecipe =
new VPWidenRecipe(*Inst, Plan->mapToVPValues(Inst->operands()));
}
}
NewRecipe->insertBefore(Ingredient);
if (NewRecipe->getNumDefinedValues() == 1)
VPV->replaceAllUsesWith(NewRecipe->getVPValue());
else
assert(NewRecipe->getNumDefinedValues() == 0 &&
"Only recpies with zero or one defined values expected");
Ingredient->eraseFromParent();
Plan->removeVPValueFor(Inst);
for (auto *Def : NewRecipe->definedValues()) {
Plan->addVPValue(Inst, Def);
}
}
}
}