[llvm] [SLP] Simplify buildTree() (NFC) (PR #138833)
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Wed May 7 02:23:37 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-transforms
Author: Gaëtan Bossu (gbossu)
<details>
<summary>Changes</summary>
This NFC aims to simplify the interfaces used in `buildTree()` to make it easier to understand where decisions for legality are made.
In particular, there is now a single point of definition for legality decisions. This makes it clear where all those decisions are made. Previously, multiple variables with a large scope were passed by reference.
---
Full diff: https://github.com/llvm/llvm-project/pull/138833.diff
1 Files Affected:
- (modified) llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp (+67-49)
``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index a6ae26f2f0e1a..32ffdff102ab7 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -4063,6 +4063,15 @@ class BoUpSLP {
}
#endif
+ /// Create a new gather TreeEntry
+ TreeEntry *newGatherTreeEntry(ArrayRef<Value *> VL,
+ const InstructionsState &S,
+ const EdgeInfo &UserTreeIdx,
+ ArrayRef<int> ReuseShuffleIndices = {}) {
+ auto Invalid = ScheduleBundle::invalid();
+ return newTreeEntry(VL, Invalid, S, UserTreeIdx, ReuseShuffleIndices);
+ }
+
/// Create a new VectorizableTree entry.
TreeEntry *newTreeEntry(ArrayRef<Value *> VL, ScheduleBundle &Bundle,
const InstructionsState &S,
@@ -4251,13 +4260,34 @@ class BoUpSLP {
bool areAltOperandsProfitable(const InstructionsState &S,
ArrayRef<Value *> VL) const;
+ /// Contains all the outputs of legality analysis for a list of values to
+ /// vectorize.
+ class ScalarsVectorizationLegality {
+ InstructionsState S;
+ bool IsLegal;
+ bool TryToFindDuplicates;
+ bool TrySplitVectorize;
+
+ public:
+ ScalarsVectorizationLegality(InstructionsState S, bool IsLegal,
+ bool TryToFindDuplicates = true,
+ bool TrySplitVectorize = false)
+ : S(S), IsLegal(IsLegal), TryToFindDuplicates(TryToFindDuplicates),
+ TrySplitVectorize(TrySplitVectorize) {
+ assert((!IsLegal || (S.valid() && TryToFindDuplicates)) &&
+ "Inconsistent state");
+ }
+ const InstructionsState &getInstructionsState() const { return S; };
+ bool isLegal() const { return IsLegal; }
+ bool tryToFindDuplicates() const { return TryToFindDuplicates; }
+ bool trySplitVectorize() const { return TrySplitVectorize; }
+ };
+
/// Checks if the specified list of the instructions/values can be vectorized
/// in general.
- bool isLegalToVectorizeScalars(ArrayRef<Value *> VL, unsigned Depth,
- const EdgeInfo &UserTreeIdx,
- InstructionsState &S,
- bool &TryToFindDuplicates,
- bool &TrySplitVectorize) const;
+ ScalarsVectorizationLegality
+ getScalarsVectorizationLegality(ArrayRef<Value *> VL, unsigned Depth,
+ const EdgeInfo &UserTreeIdx) const;
/// Checks if the specified list of the instructions/values can be vectorized
/// and fills required data before actual scheduling of the instructions.
@@ -9734,16 +9764,12 @@ bool BoUpSLP::canBuildSplitNode(ArrayRef<Value *> VL,
return true;
}
-bool BoUpSLP::isLegalToVectorizeScalars(ArrayRef<Value *> VL, unsigned Depth,
- const EdgeInfo &UserTreeIdx,
- InstructionsState &S,
- bool &TryToFindDuplicates,
- bool &TrySplitVectorize) const {
+BoUpSLP::ScalarsVectorizationLegality
+BoUpSLP::getScalarsVectorizationLegality(ArrayRef<Value *> VL, unsigned Depth,
+ const EdgeInfo &UserTreeIdx) const {
assert((allConstant(VL) || allSameType(VL)) && "Invalid types!");
- S = getSameOpcode(VL, *TLI);
- TryToFindDuplicates = true;
- TrySplitVectorize = false;
+ InstructionsState S = getSameOpcode(VL, *TLI);
// Don't go into catchswitch blocks, which can happen with PHIs.
// Such blocks can only have PHIs and the catchswitch. There is no
@@ -9751,8 +9777,8 @@ bool BoUpSLP::isLegalToVectorizeScalars(ArrayRef<Value *> VL, unsigned Depth,
if (S && isa<CatchSwitchInst>(S.getMainOp()->getParent()->getTerminator())) {
LLVM_DEBUG(dbgs() << "SLP: bundle in catchswitch block.\n");
// Do not try to pack to avoid extra instructions here.
- TryToFindDuplicates = false;
- return false;
+ return ScalarsVectorizationLegality(S, /*IsLegal=*/false,
+ /*TryToFindDuplicates=*/false);
}
// Check if this is a duplicate of another entry.
@@ -9762,14 +9788,14 @@ bool BoUpSLP::isLegalToVectorizeScalars(ArrayRef<Value *> VL, unsigned Depth,
if (E->isSame(VL)) {
LLVM_DEBUG(dbgs() << "SLP: Perfect diamond merge at " << *S.getMainOp()
<< ".\n");
- return false;
+ return ScalarsVectorizationLegality(S, /*IsLegal=*/false);
}
SmallPtrSet<Value *, 8> Values(llvm::from_range, E->Scalars);
if (all_of(VL, [&](Value *V) {
return isa<PoisonValue>(V) || Values.contains(V);
})) {
LLVM_DEBUG(dbgs() << "SLP: Gathering due to full overlap.\n");
- return false;
+ return ScalarsVectorizationLegality(S, /*IsLegal=*/false);
}
}
}
@@ -9786,7 +9812,7 @@ bool BoUpSLP::isLegalToVectorizeScalars(ArrayRef<Value *> VL, unsigned Depth,
cast<Instruction>(I)->getOpcode() == S.getOpcode();
})))) {
LLVM_DEBUG(dbgs() << "SLP: Gathering due to max recursion depth.\n");
- return false;
+ return ScalarsVectorizationLegality(S, /*IsLegal=*/false);
}
// Don't handle scalable vectors
@@ -9794,15 +9820,15 @@ bool BoUpSLP::isLegalToVectorizeScalars(ArrayRef<Value *> VL, unsigned Depth,
isa<ScalableVectorType>(
cast<ExtractElementInst>(S.getMainOp())->getVectorOperandType())) {
LLVM_DEBUG(dbgs() << "SLP: Gathering due to scalable vector type.\n");
- return false;
+ return ScalarsVectorizationLegality(S, /*IsLegal=*/false);
}
// Don't handle vectors.
if (!SLPReVec && getValueType(VL.front())->isVectorTy()) {
LLVM_DEBUG(dbgs() << "SLP: Gathering due to vector type.\n");
// Do not try to pack to avoid extra instructions here.
- TryToFindDuplicates = false;
- return false;
+ return ScalarsVectorizationLegality(S, /*IsLegal=*/false,
+ /*TryToFindDuplicates=*/false);
}
// If all of the operands are identical or constant we have a simple solution.
@@ -9892,11 +9918,12 @@ bool BoUpSLP::isLegalToVectorizeScalars(ArrayRef<Value *> VL, unsigned Depth,
if (!S) {
LLVM_DEBUG(dbgs() << "SLP: Try split and if failed, gathering due to "
"C,S,B,O, small shuffle. \n");
- TrySplitVectorize = true;
- return false;
+ return ScalarsVectorizationLegality(S, /*IsLegal=*/false,
+ /*TryToFindDuplicates=*/true,
+ /*TrySplitVectorize=*/true);
}
LLVM_DEBUG(dbgs() << "SLP: Gathering due to C,S,B,O, small shuffle. \n");
- return false;
+ return ScalarsVectorizationLegality(S, /*IsLegal=*/false);
}
// Don't vectorize ephemeral values.
@@ -9906,8 +9933,8 @@ bool BoUpSLP::isLegalToVectorizeScalars(ArrayRef<Value *> VL, unsigned Depth,
LLVM_DEBUG(dbgs() << "SLP: The instruction (" << *V
<< ") is ephemeral.\n");
// Do not try to pack to avoid extra instructions here.
- TryToFindDuplicates = false;
- return false;
+ return ScalarsVectorizationLegality(S, /*IsLegal=*/false,
+ /*TryToFindDuplicates=*/false);
}
}
}
@@ -9956,7 +9983,7 @@ bool BoUpSLP::isLegalToVectorizeScalars(ArrayRef<Value *> VL, unsigned Depth,
if (PreferScalarize) {
LLVM_DEBUG(dbgs() << "SLP: The instructions are in tree and alternate "
"node is not profitable.\n");
- return false;
+ return ScalarsVectorizationLegality(S, /*IsLegal=*/false);
}
}
@@ -9965,7 +9992,7 @@ bool BoUpSLP::isLegalToVectorizeScalars(ArrayRef<Value *> VL, unsigned Depth,
for (Value *V : VL) {
if (UserIgnoreList->contains(V)) {
LLVM_DEBUG(dbgs() << "SLP: Gathering due to gathered scalar.\n");
- return false;
+ return ScalarsVectorizationLegality(S, /*IsLegal=*/false);
}
}
}
@@ -9995,9 +10022,9 @@ bool BoUpSLP::isLegalToVectorizeScalars(ArrayRef<Value *> VL, unsigned Depth,
// Do not vectorize EH and non-returning blocks, not profitable in most
// cases.
LLVM_DEBUG(dbgs() << "SLP: bundle in unreachable block.\n");
- return false;
+ return ScalarsVectorizationLegality(S, /*IsLegal=*/false);
}
- return true;
+ return ScalarsVectorizationLegality(S, /*IsLegal=*/true);
}
void BoUpSLP::buildTreeRec(ArrayRef<Value *> VLRef, unsigned Depth,
@@ -10008,7 +10035,6 @@ void BoUpSLP::buildTreeRec(ArrayRef<Value *> VLRef, unsigned Depth,
SmallVector<int> ReuseShuffleIndices;
SmallVector<Value *> VL(VLRef.begin(), VLRef.end());
- InstructionsState S = InstructionsState::invalid();
// Tries to build split node.
auto TrySplitNode = [&](const InstructionsState &LocalState) {
SmallVector<Value *> Op1, Op2;
@@ -10042,22 +10068,20 @@ void BoUpSLP::buildTreeRec(ArrayRef<Value *> VLRef, unsigned Depth,
return true;
};
- bool TryToPackDuplicates;
- bool TrySplitVectorize;
- if (!isLegalToVectorizeScalars(VL, Depth, UserTreeIdx, S, TryToPackDuplicates,
- TrySplitVectorize)) {
- if (TrySplitVectorize) {
+ ScalarsVectorizationLegality SVL =
+ getScalarsVectorizationLegality(VL, Depth, UserTreeIdx);
+ const InstructionsState &S = SVL.getInstructionsState();
+ if (!SVL.isLegal()) {
+ if (SVL.trySplitVectorize()) {
auto [MainOp, AltOp] = getMainAltOpsNoStateVL(VL);
// Last chance to try to vectorize alternate node.
if (MainOp && AltOp && TrySplitNode(InstructionsState(MainOp, AltOp)))
return;
}
- if (TryToPackDuplicates)
+ if (SVL.tryToFindDuplicates())
tryToFindDuplicates(VL, ReuseShuffleIndices, *TTI, *TLI, S, UserTreeIdx);
- auto Invalid = ScheduleBundle::invalid();
- newTreeEntry(VL, Invalid /*not vectorized*/, S, UserTreeIdx,
- ReuseShuffleIndices);
+ newGatherTreeEntry(VL, S, UserTreeIdx, ReuseShuffleIndices);
return;
}
@@ -10068,9 +10092,7 @@ void BoUpSLP::buildTreeRec(ArrayRef<Value *> VLRef, unsigned Depth,
// Check that every instruction appears once in this bundle.
if (!tryToFindDuplicates(VL, ReuseShuffleIndices, *TTI, *TLI, S, UserTreeIdx,
/*TryPad=*/true)) {
- auto Invalid = ScheduleBundle::invalid();
- newTreeEntry(VL, Invalid /*not vectorized*/, S, UserTreeIdx,
- ReuseShuffleIndices);
+ newGatherTreeEntry(VL, S, UserTreeIdx, ReuseShuffleIndices);
return;
}
@@ -10083,9 +10105,7 @@ void BoUpSLP::buildTreeRec(ArrayRef<Value *> VLRef, unsigned Depth,
TreeEntry::EntryState State = getScalarsVectorizationState(
S, VL, IsScatterVectorizeUserTE, CurrentOrder, PointerOps);
if (State == TreeEntry::NeedToGather) {
- auto Invalid = ScheduleBundle::invalid();
- newTreeEntry(VL, Invalid /*not vectorized*/, S, UserTreeIdx,
- ReuseShuffleIndices);
+ newGatherTreeEntry(VL, S, UserTreeIdx, ReuseShuffleIndices);
return;
}
@@ -10109,9 +10129,7 @@ void BoUpSLP::buildTreeRec(ArrayRef<Value *> VLRef, unsigned Depth,
// Last chance to try to vectorize alternate node.
if (S.isAltShuffle() && ReuseShuffleIndices.empty() && TrySplitNode(S))
return;
- auto Invalid = ScheduleBundle::invalid();
- newTreeEntry(VL, Invalid /*not vectorized*/, S, UserTreeIdx,
- ReuseShuffleIndices);
+ newGatherTreeEntry(VL, S, UserTreeIdx, ReuseShuffleIndices);
NonScheduledFirst.insert(VL.front());
if (S.getOpcode() == Instruction::Load &&
BS.ScheduleRegionSize < BS.ScheduleRegionSizeLimit)
``````````
</details>
https://github.com/llvm/llvm-project/pull/138833
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