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[SLP] Normalize debug messages for newTreeEntry. #119514

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Merged
merged 5 commits into from
Dec 23, 2024
Merged

[SLP] Normalize debug messages for newTreeEntry. #119514

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b6ed2af
[SLP] Normalize debug messages for newTreeEntry.
HanKuanChen Dec 9, 2024
bc6b053
alternate op->isAltShuffle
HanKuanChen Dec 11, 2024
96862bd
dump TreeEntry after newTreeEntry
HanKuanChen Dec 12, 2024
a7de688
add LLVM_DEBUG
HanKuanChen Dec 16, 2024
edccabd
apply comment
HanKuanChen Dec 18, 2024
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69 changes: 49 additions & 20 deletions llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -8388,7 +8388,8 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,

TreeEntry *TE =
newTreeEntry(VL, Bundle, S, UserTreeIdx, ReuseShuffleIndices);
LLVM_DEBUG(dbgs() << "SLP: added a vector of PHINodes.\n");
LLVM_DEBUG(dbgs() << "SLP: added a new TreeEntry (PHINode).\n";
TE->dump());

// Keeps the reordered operands to avoid code duplication.
PHIHandler Handler(*DT, PH, VL);
Expand Down Expand Up @@ -8417,13 +8418,14 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
}
// Insert new order with initial value 0, if it does not exist,
// otherwise return the iterator to the existing one.
newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndices, CurrentOrder);
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndices, CurrentOrder);
LLVM_DEBUG(dbgs() << "SLP: added a new TreeEntry "
"(ExtractValueInst/ExtractElementInst).\n";
TE->dump());
// This is a special case, as it does not gather, but at the same time
// we are not extending buildTree_rec() towards the operands.
ValueList Op0;
Op0.assign(VL.size(), VL0->getOperand(0));
VectorizableTree.back()->setOperand(0, Op0);
TE->setOperand(*this);
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Was this change intended for this commit? It's not just about debug messages, IIUC.

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@HanKuanChen HanKuanChen Jan 9, 2025 •
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Indeed. This part is not related to the debug message.
Do you have any concern?

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We see test failures in code compiled by clang built after this commit. I wonder if this is related to the this snippet. While I'm working on a test case I briefly looked at this commit and found only one suspicious fragment - this one.

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Can you send me the test?

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In another instance, I think this is causing an infinite loop. Working on some repro

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I use the commit 539b15b as base and revert 11676da. However, reduced.ll gives me same result.

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I can reliably reproduce this and here's the same example in compiler explorer: https://gcc.godbolt.org/z/cEWPchGaE

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I mean, I could reliably reproduce this with opt built right before and at the same commit. I haven't tried it with 539b15b

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I confirmed this at b270525, but at 283dca5 this already seems to have been fixed. Searching for the fix.

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Apparently, 066b888 fixes this.

return;
}
case Instruction::InsertElement: {
Expand Down Expand Up @@ -8451,7 +8453,8 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
CurrentOrder.clear();
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
{}, CurrentOrder);
LLVM_DEBUG(dbgs() << "SLP: added inserts bundle.\n");
LLVM_DEBUG(dbgs() << "SLP: added a new TreeEntry (InsertElementInst).\n";
TE->dump());

TE->setOperand(*this);
buildTree_rec(TE->getOperand(1), Depth + 1, {TE, 1});
Expand All @@ -8471,21 +8474,28 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndices, CurrentOrder, InterleaveFactor);
if (CurrentOrder.empty())
LLVM_DEBUG(dbgs() << "SLP: added a vector of loads.\n");
LLVM_DEBUG(dbgs() << "SLP: added a new TreeEntry (LoadInst).\n";
TE->dump());
else
LLVM_DEBUG(dbgs() << "SLP: added a vector of jumbled loads.\n");
LLVM_DEBUG(dbgs()
<< "SLP: added a new TreeEntry (jumbled LoadInst).\n";
TE->dump());
break;
case TreeEntry::StridedVectorize:
// Vectorizing non-consecutive loads with `llvm.masked.gather`.
TE = newTreeEntry(VL, TreeEntry::StridedVectorize, Bundle, S,
UserTreeIdx, ReuseShuffleIndices, CurrentOrder);
LLVM_DEBUG(dbgs() << "SLP: added a vector of strided loads.\n");
LLVM_DEBUG(dbgs() << "SLP: added a new TreeEntry (strided LoadInst).\n";
TE->dump());
break;
case TreeEntry::ScatterVectorize:
// Vectorizing non-consecutive loads with `llvm.masked.gather`.
TE = newTreeEntry(VL, TreeEntry::ScatterVectorize, Bundle, S,
UserTreeIdx, ReuseShuffleIndices);
LLVM_DEBUG(dbgs() << "SLP: added a vector of non-consecutive loads.\n");
LLVM_DEBUG(
dbgs()
<< "SLP: added a new TreeEntry (non-consecutive LoadInst).\n";
TE->dump());
break;
case TreeEntry::CombinedVectorize:
case TreeEntry::NeedToGather:
Expand Down Expand Up @@ -8529,7 +8539,8 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
}
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndices);
LLVM_DEBUG(dbgs() << "SLP: added a vector of casts.\n");
LLVM_DEBUG(dbgs() << "SLP: added a new TreeEntry (CastInst).\n";
TE->dump());

TE->setOperand(*this);
for (unsigned I : seq<unsigned>(VL0->getNumOperands()))
Expand All @@ -8556,7 +8567,8 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
CmpInst::Predicate P0 = cast<CmpInst>(VL0)->getPredicate();
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndices);
LLVM_DEBUG(dbgs() << "SLP: added a vector of compares.\n");
LLVM_DEBUG(dbgs() << "SLP: added a new TreeEntry (CmpInst).\n";
TE->dump());

ValueList Left, Right;
VLOperands Ops(VL, VL0, *this);
Expand Down Expand Up @@ -8626,7 +8638,10 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
case Instruction::Freeze: {
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndices);
LLVM_DEBUG(dbgs() << "SLP: added a vector of un/bin op.\n");
LLVM_DEBUG(
dbgs() << "SLP: added a new TreeEntry "
"(SelectInst/UnaryOperator/BinaryOperator/FreezeInst).\n";
TE->dump());

TE->setOperand(*this, isa<BinaryOperator>(VL0) && isCommutative(VL0));
for (unsigned I : seq<unsigned>(VL0->getNumOperands()))
Expand All @@ -8636,7 +8651,8 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
case Instruction::GetElementPtr: {
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndices);
LLVM_DEBUG(dbgs() << "SLP: added a vector of GEPs.\n");
LLVM_DEBUG(dbgs() << "SLP: added a new TreeEntry (GetElementPtrInst).\n";
TE->dump());
SmallVector<ValueList, 2> Operands(2);
// Prepare the operand vector for pointer operands.
for (Value *V : VL) {
Expand Down Expand Up @@ -8694,12 +8710,15 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
fixupOrderingIndices(CurrentOrder);
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndices, CurrentOrder);
TE->setOperand(*this);
buildTree_rec(TE->getOperand(0), Depth + 1, {TE, 0});
if (Consecutive)
LLVM_DEBUG(dbgs() << "SLP: added a vector of stores.\n");
LLVM_DEBUG(dbgs() << "SLP: added a new TreeEntry (StoreInst).\n";
TE->dump());
else
LLVM_DEBUG(dbgs() << "SLP: added a vector of jumbled stores.\n");
LLVM_DEBUG(
dbgs() << "SLP: added a new TreeEntry (jumbled StoreInst).\n";
TE->dump());
TE->setOperand(*this);
buildTree_rec(TE->getOperand(0), Depth + 1, {TE, 0});
return;
}
case Instruction::Call: {
Expand All @@ -8710,6 +8729,8 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,

TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndices);
LLVM_DEBUG(dbgs() << "SLP: added a new TreeEntry (CallInst).\n";
TE->dump());
TE->setOperand(*this, isCommutative(VL0));
for (unsigned I : seq<unsigned>(CI->arg_size())) {
// For scalar operands no need to create an entry since no need to
Expand All @@ -8723,7 +8744,15 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
case Instruction::ShuffleVector: {
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndices);
LLVM_DEBUG(dbgs() << "SLP: added a ShuffleVector op.\n");
if (S.isAltShuffle()) {
LLVM_DEBUG(dbgs() << "SLP: added a new TreeEntry (isAltShuffle).\n";
TE->dump());
} else {
assert(SLPReVec && "Only supported by REVEC.");
LLVM_DEBUG(
dbgs() << "SLP: added a new TreeEntry (ShuffleVectorInst).\n";
TE->dump());
}

// Reorder operands if reordering would enable vectorization.
auto *CI = dyn_cast<CmpInst>(VL0);
Expand Down
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