[llvm] [VPlan] Add new VPIRPhi overlay for VPIRInsts wrapping phi nodes (NFC). (PR #129387)
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Sat Mar 1 07:34:12 PST 2025
https://github.com/fhahn created https://github.com/llvm/llvm-project/pull/129387
Add a new VPIRPhi subclass of VPIRInstruction, that purely serves as an overlay, to provide more convenient checking (via directly doing isa/dyn_cast/cast) and specialied execute/print implementations.
Both VPIRInstruction and VPIRPhi share the same VPDefID, and are differentiated by the backing IR instruction.
This pattern could alos be used to provide more specialized interfaces for some VPInstructions ocpodes, without introducing new, completely spearate recipes. An example would be modeling VPWidenPHIRecipe & VPScalarPHIRecip using VPInstructions opcodes and providing an interface to retrieve incoming blocks and values through a VPInstruction subclass similar to VPIRPhi.
>From c305e73d748277823b65c0ee5ddbee107e557f9b Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Fri, 28 Feb 2025 14:03:45 +0000
Subject: [PATCH] [VPlan] Add new VPIRPhi overlay for VPIRInsts wrapping phi
nodes (NFC).
Add a new VPIRPhi subclass of VPIRInstruction, that purely serves as an
overlay, to provide more convenient checking (via directly doing
isa/dyn_cast/cast) and specialied execute/print implementations.
Both VPIRInstruction and VPIRPhi share the same VPDefID, and are
differentiated by the backing IR instruction.
This pattern could alos be used to provide more specialized interfaces for
some VPInstructions ocpodes, without introducing new, completely
spearate recipes. An example would be modeling VPWidenPHIRecipe &
VPScalarPHIRecip using VPInstructions opcodes and providing an interface
to retrieve incoming blocks and values through a VPInstruction subclass
similar to VPIRPhi.
---
.../Transforms/Vectorize/LoopVectorize.cpp | 24 ++++---
llvm/lib/Transforms/Vectorize/VPlan.cpp | 2 +-
llvm/lib/Transforms/Vectorize/VPlan.h | 28 +++++++-
.../lib/Transforms/Vectorize/VPlanRecipes.cpp | 65 ++++++++++++-------
.../Transforms/Vectorize/VPlanTransforms.cpp | 14 ++--
.../Transforms/Vectorize/VPlanVerifier.cpp | 6 +-
6 files changed, 89 insertions(+), 50 deletions(-)
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index e2612698b6b0f..bfbd698b140ad 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -9089,14 +9089,14 @@ static void addScalarResumePhis(VPRecipeBuilder &Builder, VPlan &Plan,
VPValue *OneVPV = Plan.getOrAddLiveIn(
ConstantInt::get(Plan.getCanonicalIV()->getScalarType(), 1));
for (VPRecipeBase &ScalarPhiR : *Plan.getScalarHeader()) {
- auto *ScalarPhiIRI = cast<VPIRInstruction>(&ScalarPhiR);
- auto *ScalarPhiI = dyn_cast<PHINode>(&ScalarPhiIRI->getInstruction());
- if (!ScalarPhiI)
+ auto *ScalarPhiIRI = dyn_cast<VPIRPhi>(&ScalarPhiR);
+ if (!ScalarPhiIRI)
break;
// TODO: Extract final value from induction recipe initially, optimize to
// pre-computed end value together in optimizeInductionExitUsers.
- auto *VectorPhiR = cast<VPHeaderPHIRecipe>(Builder.getRecipe(ScalarPhiI));
+ auto *VectorPhiR =
+ cast<VPHeaderPHIRecipe>(Builder.getRecipe(&ScalarPhiIRI->getIRPhi()));
if (auto *WideIVR = dyn_cast<VPWidenInductionRecipe>(VectorPhiR)) {
if (VPInstruction *ResumePhi = addResumePhiRecipeForInduction(
WideIVR, VectorPHBuilder, ScalarPHBuilder, TypeInfo,
@@ -9146,11 +9146,8 @@ collectUsersInExitBlocks(Loop *OrigLoop, VPRecipeBuilder &Builder,
continue;
for (VPRecipeBase &R : *ExitVPBB) {
- auto *ExitIRI = dyn_cast<VPIRInstruction>(&R);
+ auto *ExitIRI = dyn_cast<VPIRPhi>(&R);
if (!ExitIRI)
- continue;
- auto *ExitPhi = dyn_cast<PHINode>(&ExitIRI->getInstruction());
- if (!ExitPhi)
break;
if (ExitVPBB->getSinglePredecessor() != Plan.getMiddleBlock()) {
assert(ExitIRI->getNumOperands() ==
@@ -9158,8 +9155,10 @@ collectUsersInExitBlocks(Loop *OrigLoop, VPRecipeBuilder &Builder,
"early-exit must update exit values on construction");
continue;
}
+
+ PHINode &ExitPhi = ExitIRI->getIRPhi();
BasicBlock *ExitingBB = OrigLoop->getLoopLatch();
- Value *IncomingValue = ExitPhi->getIncomingValueForBlock(ExitingBB);
+ Value *IncomingValue = ExitPhi.getIncomingValueForBlock(ExitingBB);
VPValue *V = Builder.getVPValueOrAddLiveIn(IncomingValue);
ExitIRI->addOperand(V);
if (V->isLiveIn())
@@ -10297,11 +10296,10 @@ static void preparePlanForMainVectorLoop(VPlan &MainPlan, VPlan &EpiPlan) {
cast<PHINode>(R.getVPSingleValue()->getUnderlyingValue()));
}
for (VPRecipeBase &R : make_early_inc_range(*MainPlan.getScalarHeader())) {
- auto *VPIRInst = cast<VPIRInstruction>(&R);
- auto *IRI = dyn_cast<PHINode>(&VPIRInst->getInstruction());
- if (!IRI)
+ auto *VPIRInst = dyn_cast<VPIRPhi>(&R);
+ if (!VPIRInst)
break;
- if (EpiWidenedPhis.contains(IRI))
+ if (EpiWidenedPhis.contains(&VPIRInst->getIRPhi()))
continue;
// There is no corresponding wide induction in the epilogue plan that would
// need a resume value. Remove the VPIRInst wrapping the scalar header phi
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.cpp b/llvm/lib/Transforms/Vectorize/VPlan.cpp
index 563784e4af924..8a7d5a904c46b 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlan.cpp
@@ -1295,7 +1295,7 @@ VPIRBasicBlock *VPlan::createVPIRBasicBlock(BasicBlock *IRBB) {
auto *VPIRBB = createEmptyVPIRBasicBlock(IRBB);
for (Instruction &I :
make_range(IRBB->begin(), IRBB->getTerminator()->getIterator()))
- VPIRBB->appendRecipe(new VPIRInstruction(I));
+ VPIRBB->appendRecipe(VPIRInstruction::create(I));
return VPIRBB;
}
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 70e684826ed2d..1c6099e6d8d9f 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -1032,16 +1032,19 @@ class VPInstruction : public VPRecipeWithIRFlags,
class VPIRInstruction : public VPRecipeBase {
Instruction &I;
-public:
+protected:
VPIRInstruction(Instruction &I)
: VPRecipeBase(VPDef::VPIRInstructionSC, ArrayRef<VPValue *>()), I(I) {}
+public:
~VPIRInstruction() override = default;
+ static VPIRInstruction *create(Instruction &I);
+
VP_CLASSOF_IMPL(VPDef::VPIRInstructionSC)
VPIRInstruction *clone() override {
- auto *R = new VPIRInstruction(I);
+ auto *R = create(I);
for (auto *Op : operands())
R->addOperand(Op);
return R;
@@ -1085,6 +1088,27 @@ class VPIRInstruction : public VPRecipeBase {
void extractLastLaneOfOperand(VPBuilder &Builder);
};
+/// An overlay for VPIRInstructions wrapping PHI nodes enabling convenient use
+/// cast/dyn_cast/isa and execute() implementation.
+struct VPIRPhi : public VPIRInstruction {
+ VPIRPhi(PHINode &PN) : VPIRInstruction(PN) {}
+
+ static inline bool classof(const VPRecipeBase *U) {
+ auto *R = dyn_cast<VPIRInstruction>(U);
+ return R && isa<PHINode>(R->getInstruction());
+ }
+
+ PHINode &getIRPhi() { return cast<PHINode>(getInstruction()); }
+
+ void execute(VPTransformState &State) override;
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+ /// Print the recipe.
+ void print(raw_ostream &O, const Twine &Indent,
+ VPSlotTracker &SlotTracker) const override;
+#endif
+};
+
/// VPWidenRecipe is a recipe for producing a widened instruction using the
/// opcode and operands of the recipe. This recipe covers most of the
/// traditional vectorization cases where each recipe transforms into a
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index e9f50e88867b2..0a315e85f33ec 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -961,30 +961,15 @@ void VPInstruction::print(raw_ostream &O, const Twine &Indent,
}
#endif
-void VPIRInstruction::execute(VPTransformState &State) {
- assert((isa<PHINode>(&I) || getNumOperands() == 0) &&
- "Only PHINodes can have extra operands");
- for (const auto &[Idx, Op] : enumerate(operands())) {
- VPValue *ExitValue = Op;
- auto Lane = vputils::isUniformAfterVectorization(ExitValue)
- ? VPLane::getFirstLane()
- : VPLane::getLastLaneForVF(State.VF);
- VPBlockBase *Pred = getParent()->getPredecessors()[Idx];
- auto *PredVPBB = Pred->getExitingBasicBlock();
- BasicBlock *PredBB = State.CFG.VPBB2IRBB[PredVPBB];
- // Set insertion point in PredBB in case an extract needs to be generated.
- // TODO: Model extracts explicitly.
- State.Builder.SetInsertPoint(PredBB, PredBB->getFirstNonPHIIt());
- Value *V = State.get(ExitValue, VPLane(Lane));
- auto *Phi = cast<PHINode>(&I);
- // If there is no existing block for PredBB in the phi, add a new incoming
- // value. Otherwise update the existing incoming value for PredBB.
- if (Phi->getBasicBlockIndex(PredBB) == -1)
- Phi->addIncoming(V, PredBB);
- else
- Phi->setIncomingValueForBlock(PredBB, V);
- }
+VPIRInstruction *VPIRInstruction ::create(Instruction &I) {
+ if (auto *Phi = dyn_cast<PHINode>(&I))
+ return new VPIRPhi(*Phi);
+ return new VPIRInstruction(I);
+}
+void VPIRInstruction::execute(VPTransformState &State) {
+ assert(!isa<VPIRPhi>(this) && getNumOperands() == 0 &&
+ "PHINodes must be handled by VPIRPhi");
// Advance the insert point after the wrapped IR instruction. This allows
// interleaving VPIRInstructions and other recipes.
State.Builder.SetInsertPoint(I.getParent(), std::next(I.getIterator()));
@@ -1017,6 +1002,40 @@ void VPIRInstruction::extractLastLaneOfOperand(VPBuilder &Builder) {
void VPIRInstruction::print(raw_ostream &O, const Twine &Indent,
VPSlotTracker &SlotTracker) const {
O << Indent << "IR " << I;
+}
+#endif
+
+void VPIRPhi::execute(VPTransformState &State) {
+ PHINode *Phi = &getIRPhi();
+ for (const auto &[Idx, Op] : enumerate(operands())) {
+ VPValue *ExitValue = Op;
+ auto Lane = vputils::isUniformAfterVectorization(ExitValue)
+ ? VPLane::getFirstLane()
+ : VPLane::getLastLaneForVF(State.VF);
+ VPBlockBase *Pred = getParent()->getPredecessors()[Idx];
+ auto *PredVPBB = Pred->getExitingBasicBlock();
+ BasicBlock *PredBB = State.CFG.VPBB2IRBB[PredVPBB];
+ // Set insertion point in PredBB in case an extract needs to be generated.
+ // TODO: Model extracts explicitly.
+ State.Builder.SetInsertPoint(PredBB, PredBB->getFirstNonPHIIt());
+ Value *V = State.get(ExitValue, VPLane(Lane));
+ // If there is no existing block for PredBB in the phi, add a new incoming
+ // value. Otherwise update the existing incoming value for PredBB.
+ if (Phi->getBasicBlockIndex(PredBB) == -1)
+ Phi->addIncoming(V, PredBB);
+ else
+ Phi->setIncomingValueForBlock(PredBB, V);
+ }
+
+ // Advance the insert point after the wrapped IR instruction. This allows
+ // interleaving VPIRInstructions and other recipes.
+ State.Builder.SetInsertPoint(Phi->getParent(), std::next(Phi->getIterator()));
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void VPIRPhi::print(raw_ostream &O, const Twine &Indent,
+ VPSlotTracker &SlotTracker) const {
+ VPIRInstruction::print(O, Indent, SlotTracker);
if (getNumOperands() != 0) {
O << " (extra operand" << (getNumOperands() > 1 ? "s" : "") << ": ";
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index b09933cd0e186..8627571e66b6c 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -749,8 +749,8 @@ void VPlanTransforms::optimizeInductionExitUsers(
VPTypeAnalysis TypeInfo(Plan.getCanonicalIV()->getScalarType());
VPBuilder B(Plan.getMiddleBlock()->getTerminator());
for (VPRecipeBase &R : *ExitVPBB) {
- auto *ExitIRI = cast<VPIRInstruction>(&R);
- if (!isa<PHINode>(ExitIRI->getInstruction()))
+ auto *ExitIRI = dyn_cast<VPIRPhi>(&R);
+ if (!ExitIRI)
break;
VPValue *Incoming;
@@ -2088,20 +2088,20 @@ void VPlanTransforms::handleUncountableEarlyExit(
VPBuilder MiddleBuilder(NewMiddle);
VPBuilder EarlyExitB(VectorEarlyExitVPBB);
for (VPRecipeBase &R : *VPEarlyExitBlock) {
- auto *ExitIRI = cast<VPIRInstruction>(&R);
- auto *ExitPhi = dyn_cast<PHINode>(&ExitIRI->getInstruction());
- if (!ExitPhi)
+ auto *ExitIRI = dyn_cast<VPIRPhi>(&R);
+ if (!ExitIRI)
break;
+ PHINode &ExitPhi = ExitIRI->getIRPhi();
VPValue *IncomingFromEarlyExit = RecipeBuilder.getVPValueOrAddLiveIn(
- ExitPhi->getIncomingValueForBlock(UncountableExitingBlock));
+ ExitPhi.getIncomingValueForBlock(UncountableExitingBlock));
if (OrigLoop->getUniqueExitBlock()) {
// If there's a unique exit block, VPEarlyExitBlock has 2 predecessors
// (MiddleVPBB and NewMiddle). Add the incoming value from MiddleVPBB
// which is coming from the original latch.
VPValue *IncomingFromLatch = RecipeBuilder.getVPValueOrAddLiveIn(
- ExitPhi->getIncomingValueForBlock(OrigLoop->getLoopLatch()));
+ ExitPhi.getIncomingValueForBlock(OrigLoop->getLoopLatch()));
ExitIRI->addOperand(IncomingFromLatch);
ExitIRI->extractLastLaneOfOperand(MiddleBuilder);
}
diff --git a/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp b/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
index a4b309d6dcd9f..f98323b77c708 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
@@ -204,10 +204,8 @@ bool VPlanVerifier::verifyVPBasicBlock(const VPBasicBlock *VPBB) {
for (const VPUser *U : V->users()) {
auto *UI = cast<VPRecipeBase>(U);
// TODO: check dominance of incoming values for phis properly.
- if (!UI ||
- isa<VPHeaderPHIRecipe, VPWidenPHIRecipe, VPPredInstPHIRecipe>(UI) ||
- (isa<VPIRInstruction>(UI) &&
- isa<PHINode>(cast<VPIRInstruction>(UI)->getInstruction())))
+ if (!UI || isa<VPHeaderPHIRecipe, VPWidenPHIRecipe, VPPredInstPHIRecipe,
+ VPIRPhi>(UI))
continue;
// If the user is in the same block, check it comes after R in the
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