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Revert "[SLP] Fix for PR6246: vectorization for scalar ops on vector …
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…elements."

This reverts commit r288497, as it broke the AArch64 build of Compiler-RT's
builtins (twice: once in r288412 and once in r288497). We should investigate
this offline.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288508 91177308-0d34-0410-b5e6-96231b3b80d8
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rengolin committed Dec 2, 2016
1 parent 42285f5 commit 66e793d
Showing 3 changed files with 840 additions and 440 deletions.
140 changes: 66 additions & 74 deletions lib/Transforms/Vectorize/SLPVectorizer.cpp
Original file line number Diff line number Diff line change
@@ -3870,11 +3870,10 @@ bool SLPVectorizerPass::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R,

unsigned Opcode0 = I0->getOpcode();

// FIXME: Register size should be a parameter to this function, so we can
// try different vectorization factors.
unsigned Sz = R.getVectorElementSize(I0);
unsigned MinVF = std::max(2U, R.getMinVecRegSize() / Sz);
unsigned MaxVF = std::max<unsigned>(PowerOf2Floor(VL.size()), MinVF);
if (MaxVF < 2)
return false;
unsigned VF = R.getMinVecRegSize() / Sz;

for (Value *V : VL) {
Type *Ty = V->getType();
@@ -3890,83 +3889,76 @@ bool SLPVectorizerPass::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R,
// Keep track of values that were deleted by vectorizing in the loop below.
SmallVector<WeakVH, 8> TrackValues(VL.begin(), VL.end());

unsigned NextInst = 0, MaxInst = VL.size();
for (unsigned VF = MaxVF; NextInst + 1 < MaxInst && VF >= MinVF;
VF /= 2) {
for (unsigned I = NextInst; I < MaxInst; ++I) {
unsigned OpsWidth = 0;
for (unsigned i = 0, e = VL.size(); i < e; ++i) {
unsigned OpsWidth = 0;

if (I + VF > MaxInst)
OpsWidth = MaxInst - I;
else
OpsWidth = VF;
if (i + VF > e)
OpsWidth = e - i;
else
OpsWidth = VF;

if (!isPowerOf2_32(OpsWidth) || OpsWidth < 2)
break;
if (!isPowerOf2_32(OpsWidth) || OpsWidth < 2)
break;

// Check that a previous iteration of this loop did not delete the Value.
if (hasValueBeenRAUWed(VL, TrackValues, I, OpsWidth))
continue;
// Check that a previous iteration of this loop did not delete the Value.
if (hasValueBeenRAUWed(VL, TrackValues, i, OpsWidth))
continue;

DEBUG(dbgs() << "SLP: Analyzing " << OpsWidth << " operations "
<< "\n");
ArrayRef<Value *> Ops = VL.slice(I, OpsWidth);

ArrayRef<Value *> BuildVectorSlice;
if (!BuildVector.empty())
BuildVectorSlice = BuildVector.slice(I, OpsWidth);

R.buildTree(Ops, BuildVectorSlice);
// TODO: check if we can allow reordering for more cases.
if (AllowReorder && R.shouldReorder()) {
// Conceptually, there is nothing actually preventing us from trying to
// reorder a larger list. In fact, we do exactly this when vectorizing
// reductions. However, at this point, we only expect to get here from
// tryToVectorizePair().
assert(Ops.size() == 2);
assert(BuildVectorSlice.empty());
Value *ReorderedOps[] = {Ops[1], Ops[0]};
R.buildTree(ReorderedOps, None);
}
if (R.isTreeTinyAndNotFullyVectorizable())
continue;
DEBUG(dbgs() << "SLP: Analyzing " << OpsWidth << " operations "
<< "\n");
ArrayRef<Value *> Ops = VL.slice(i, OpsWidth);

ArrayRef<Value *> BuildVectorSlice;
if (!BuildVector.empty())
BuildVectorSlice = BuildVector.slice(i, OpsWidth);

R.buildTree(Ops, BuildVectorSlice);
// TODO: check if we can allow reordering for more cases.
if (AllowReorder && R.shouldReorder()) {
// Conceptually, there is nothing actually preventing us from trying to
// reorder a larger list. In fact, we do exactly this when vectorizing
// reductions. However, at this point, we only expect to get here from
// tryToVectorizePair().
assert(Ops.size() == 2);
assert(BuildVectorSlice.empty());
Value *ReorderedOps[] = { Ops[1], Ops[0] };
R.buildTree(ReorderedOps, None);
}
if (R.isTreeTinyAndNotFullyVectorizable())
continue;

R.computeMinimumValueSizes();
int Cost = R.getTreeCost();

if (Cost < -SLPCostThreshold) {
DEBUG(dbgs() << "SLP: Vectorizing list at cost:" << Cost << ".\n");
Value *VectorizedRoot = R.vectorizeTree();

// Reconstruct the build vector by extracting the vectorized root. This
// way we handle the case where some elements of the vector are
// undefined.
// (return (inserelt <4 xi32> (insertelt undef (opd0) 0) (opd1) 2))
if (!BuildVectorSlice.empty()) {
// The insert point is the last build vector instruction. The
// vectorized root will precede it. This guarantees that we get an
// instruction. The vectorized tree could have been constant folded.
Instruction *InsertAfter = cast<Instruction>(BuildVectorSlice.back());
unsigned VecIdx = 0;
for (auto &V : BuildVectorSlice) {
IRBuilder<NoFolder> Builder(InsertAfter->getParent(),
++BasicBlock::iterator(InsertAfter));
Instruction *I = cast<Instruction>(V);
assert(isa<InsertElementInst>(I) || isa<InsertValueInst>(I));
Instruction *Extract =
cast<Instruction>(Builder.CreateExtractElement(
VectorizedRoot, Builder.getInt32(VecIdx++)));
I->setOperand(1, Extract);
I->removeFromParent();
I->insertAfter(Extract);
InsertAfter = I;
}
R.computeMinimumValueSizes();
int Cost = R.getTreeCost();

if (Cost < -SLPCostThreshold) {
DEBUG(dbgs() << "SLP: Vectorizing list at cost:" << Cost << ".\n");
Value *VectorizedRoot = R.vectorizeTree();

// Reconstruct the build vector by extracting the vectorized root. This
// way we handle the case where some elements of the vector are undefined.
// (return (inserelt <4 xi32> (insertelt undef (opd0) 0) (opd1) 2))
if (!BuildVectorSlice.empty()) {
// The insert point is the last build vector instruction. The vectorized
// root will precede it. This guarantees that we get an instruction. The
// vectorized tree could have been constant folded.
Instruction *InsertAfter = cast<Instruction>(BuildVectorSlice.back());
unsigned VecIdx = 0;
for (auto &V : BuildVectorSlice) {
IRBuilder<NoFolder> Builder(InsertAfter->getParent(),
++BasicBlock::iterator(InsertAfter));
Instruction *I = cast<Instruction>(V);
assert(isa<InsertElementInst>(I) || isa<InsertValueInst>(I));
Instruction *Extract = cast<Instruction>(Builder.CreateExtractElement(
VectorizedRoot, Builder.getInt32(VecIdx++)));
I->setOperand(1, Extract);
I->removeFromParent();
I->insertAfter(Extract);
InsertAfter = I;
}
// Move to the next bundle.
I += VF - 1;
NextInst = I + 1;
Changed = true;
}
// Move to the next bundle.
i += VF - 1;
Changed = true;
}
}

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