[llvm] [VPlan][NFC] Add new getMiddleBlock interface to VPlan (PR #113558)
David Sherwood via llvm-commits
llvm-commits at lists.llvm.org
Thu Oct 31 04:19:11 PDT 2024
https://github.com/david-arm updated https://github.com/llvm/llvm-project/pull/113558
>From a1f8aa654c015a9a20fb71d0d695aa1d79938f1e Mon Sep 17 00:00:00 2001
From: David Sherwood <david.sherwood at arm.com>
Date: Thu, 24 Oct 2024 12:43:49 +0000
Subject: [PATCH 1/2] [VPlan][NFC] Add new getMiddleBlock interface to VPlan
This work is in preparation for PRs #112138 and #88385 where
the middle block is not guaranteed to be the immediate successor
to the region block. I've simply add new getMiddleBlock()
interfaces to VPlan that for now just return
cast<VPBasicBlock>(VectorRegion->getSingleSuccessor())
Once PR #112138 lands we'll need to do more work to discover
the middle block.
---
llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 17 ++++++-----------
llvm/lib/Transforms/Vectorize/VPlan.cpp | 4 ++--
llvm/lib/Transforms/Vectorize/VPlan.h | 8 ++++++++
llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp | 3 +--
llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp | 3 +--
5 files changed, 18 insertions(+), 17 deletions(-)
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 3d638e52328b57..5cd2ec9762f33a 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -7706,8 +7706,7 @@ DenseMap<const SCEV *, Value *> LoopVectorizationPlanner::executePlan(
BestVPlan.execute(&State);
// 2.5 Collect reduction resume values.
- auto *ExitVPBB =
- cast<VPBasicBlock>(BestVPlan.getVectorLoopRegion()->getSingleSuccessor());
+ auto *ExitVPBB = BestVPlan.getMiddleBlock();
if (VectorizingEpilogue)
for (VPRecipeBase &R : *ExitVPBB) {
fixReductionScalarResumeWhenVectorizingEpilog(
@@ -8798,8 +8797,7 @@ static void addCanonicalIVRecipes(VPlan &Plan, Type *IdxTy, bool HasNUW,
static SetVector<VPIRInstruction *> collectUsersInExitBlock(
Loop *OrigLoop, VPRecipeBuilder &Builder, VPlan &Plan,
const MapVector<PHINode *, InductionDescriptor> &Inductions) {
- auto *MiddleVPBB =
- cast<VPBasicBlock>(Plan.getVectorLoopRegion()->getSingleSuccessor());
+ auto *MiddleVPBB = Plan.getMiddleBlock();
// No edge from the middle block to the unique exit block has been inserted
// and there is nothing to fix from vector loop; phis should have incoming
// from scalar loop only.
@@ -8845,8 +8843,7 @@ addUsersInExitBlock(VPlan &Plan,
if (ExitUsersToFix.empty())
return;
- auto *MiddleVPBB =
- cast<VPBasicBlock>(Plan.getVectorLoopRegion()->getSingleSuccessor());
+ auto *MiddleVPBB = Plan.getMiddleBlock();
VPBuilder B(MiddleVPBB, MiddleVPBB->getFirstNonPhi());
// Introduce extract for exiting values and update the VPIRInstructions
@@ -8883,7 +8880,7 @@ static void addLiveOutsForFirstOrderRecurrences(
// TODO: Should be replaced by
// Plan->getScalarLoopRegion()->getSinglePredecessor() in the future once the
// scalar region is modeled as well.
- auto *MiddleVPBB = cast<VPBasicBlock>(VectorRegion->getSingleSuccessor());
+ auto *MiddleVPBB = Plan.getMiddleBlock();
VPBasicBlock *ScalarPHVPBB = nullptr;
if (MiddleVPBB->getNumSuccessors() == 2) {
// Order is strict: first is the exit block, second is the scalar preheader.
@@ -9085,8 +9082,7 @@ LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(VFRange &Range) {
bool NeedsBlends = BB != HeaderBB && !BB->phis().empty();
return Legal->blockNeedsPredication(BB) || NeedsBlends;
});
- auto *MiddleVPBB =
- cast<VPBasicBlock>(Plan->getVectorLoopRegion()->getSingleSuccessor());
+ auto *MiddleVPBB = Plan->getMiddleBlock();
VPBasicBlock::iterator MBIP = MiddleVPBB->getFirstNonPhi();
for (BasicBlock *BB : make_range(DFS.beginRPO(), DFS.endRPO())) {
// Relevant instructions from basic block BB will be grouped into VPRecipe
@@ -9305,8 +9301,7 @@ void LoopVectorizationPlanner::adjustRecipesForReductions(
using namespace VPlanPatternMatch;
VPRegionBlock *VectorLoopRegion = Plan->getVectorLoopRegion();
VPBasicBlock *Header = VectorLoopRegion->getEntryBasicBlock();
- VPBasicBlock *MiddleVPBB =
- cast<VPBasicBlock>(VectorLoopRegion->getSingleSuccessor());
+ VPBasicBlock *MiddleVPBB = Plan->getMiddleBlock();
for (VPRecipeBase &R : Header->phis()) {
auto *PhiR = dyn_cast<VPReductionPHIRecipe>(&R);
if (!PhiR || !PhiR->isInLoop() || (MinVF.isScalar() && !PhiR->isOrdered()))
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.cpp b/llvm/lib/Transforms/Vectorize/VPlan.cpp
index 0484543d2d0398..d69eaeb785f50c 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlan.cpp
@@ -1030,8 +1030,8 @@ void VPlan::execute(VPTransformState *State) {
// skeleton creation, so we can only create the VPIRBasicBlocks now during
// VPlan execution rather than earlier during VPlan construction.
BasicBlock *MiddleBB = State->CFG.ExitBB;
- VPBasicBlock *MiddleVPBB =
- cast<VPBasicBlock>(getVectorLoopRegion()->getSingleSuccessor());
+ VPBasicBlock *MiddleVPBB = getMiddleBlock();
+
// Find the VPBB for the scalar preheader, relying on the current structure
// when creating the middle block and its successrs: if there's a single
// predecessor, it must be the scalar preheader. Otherwise, the second
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 0e0c64f6df9cba..a12ce1e847c2ff 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -3773,6 +3773,14 @@ class VPlan {
VPBasicBlock *getEntry() { return Entry; }
const VPBasicBlock *getEntry() const { return Entry; }
+ /// Methods to support access to the middle block.
+ const VPBasicBlock *getMiddleBlock() const {
+ return cast<VPBasicBlock>(getVectorLoopRegion()->getSingleSuccessor());
+ }
+ VPBasicBlock *getMiddleBlock() {
+ return cast<VPBasicBlock>(getVectorLoopRegion()->getSingleSuccessor());
+ }
+
/// The trip count of the original loop.
VPValue *getTripCount() const {
assert(TripCount && "trip count needs to be set before accessing it");
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index de7023167df899..7be7e7156092bb 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -216,8 +216,7 @@ bool VPRecipeBase::mayHaveSideEffects() const {
void VPLiveOut::fixPhi(VPlan &Plan, VPTransformState &State) {
VPValue *ExitValue = getOperand(0);
- VPBasicBlock *MiddleVPBB =
- cast<VPBasicBlock>(Plan.getVectorLoopRegion()->getSingleSuccessor());
+ VPBasicBlock *MiddleVPBB = Plan.getMiddleBlock();
VPRecipeBase *ExitingRecipe = ExitValue->getDefiningRecipe();
auto *ExitingVPBB = ExitingRecipe ? ExitingRecipe->getParent() : nullptr;
// Values leaving the vector loop reach live out phi's in the exiting block
diff --git a/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp b/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
index 7ea5ee341cc547..1cccd8a5bab7fe 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
@@ -248,8 +248,7 @@ bool VPlanVerifier::verifyVPBasicBlock(const VPBasicBlock *VPBB) {
return false;
}
- VPBlockBase *MiddleBB =
- IRBB->getPlan()->getVectorLoopRegion()->getSingleSuccessor();
+ const VPBasicBlock *MiddleBB = IRBB->getPlan()->getMiddleBlock();
if (IRBB != IRBB->getPlan()->getPreheader() &&
IRBB->getSinglePredecessor() != MiddleBB) {
errs() << "VPIRBasicBlock can only be used as pre-header or a successor of "
>From e915a817ba883bd265ed0644298f159c53f35ce0 Mon Sep 17 00:00:00 2001
From: David Sherwood <david.sherwood at arm.com>
Date: Thu, 31 Oct 2024 11:16:57 +0000
Subject: [PATCH 2/2] Address review comment
---
llvm/lib/Transforms/Vectorize/VPlan.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index a12ce1e847c2ff..0bd627592600d5 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -3773,7 +3773,9 @@ class VPlan {
VPBasicBlock *getEntry() { return Entry; }
const VPBasicBlock *getEntry() const { return Entry; }
- /// Methods to support access to the middle block.
+ /// Returns the 'middle' block of the plan, that is the block that selects
+ /// whether to execute the scalar tail loop or the exit block from the loop
+ /// latch.
const VPBasicBlock *getMiddleBlock() const {
return cast<VPBasicBlock>(getVectorLoopRegion()->getSingleSuccessor());
}
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