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SLP Vectorizer: improve canonicalize tree operands of commutitive binary operands. 

This reverts r214338 (except the test file) and replaces it with a more general algorithm.

llvm-svn: 214485
This commit is contained in:
Erik Eckstein 2014-08-01 08:05:55 +00:00
parent 58fab766e6
commit 4944b2ff94
1 changed files with 41 additions and 28 deletions
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69
llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
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@ -396,7 +396,8 @@ public:
BoUpSLP(Function *Func, ScalarEvolution *Se, const DataLayout *Dl,
TargetTransformInfo *Tti, TargetLibraryInfo *TLi, AliasAnalysis *Aa,
LoopInfo *Li, DominatorTree *Dt)
: F(Func), SE(Se), DL(Dl), TTI(Tti), TLI(TLi), AA(Aa), LI(Li), DT(Dt),
: NumLoadsWantToKeepOrder(0), NumLoadsWantToChangeOrder(0),
F(Func), SE(Se), DL(Dl), TTI(Tti), TLI(TLi), AA(Aa), LI(Li), DT(Dt),
Builder(Se->getContext()) {}
/// \brief Vectorize the tree that starts with the elements in \p VL.
@ -419,6 +420,8 @@ public:
MustGather.clear();
ExternalUses.clear();
MemBarrierIgnoreList.clear();
NumLoadsWantToKeepOrder = 0;
NumLoadsWantToChangeOrder = 0;
}
/// \returns true if the memory operations A and B are consecutive.
@ -427,10 +430,9 @@ public:
/// \brief Perform LICM and CSE on the newly generated gather sequences.
void optimizeGatherSequence();
/// \brief Get the instruction numbering for a given Instruction.
int getIndex(Instruction *I) {
BlockNumbering &BN = getBlockNumbering(I->getParent());
return BN.getIndex(I);
/// \returns true if it is benefitial to reverse the vector order.
bool shouldReorder() const {
return NumLoadsWantToChangeOrder > NumLoadsWantToKeepOrder;
}
private:
@ -586,6 +588,12 @@ private:
/// List of users to ignore during scheduling and that don't need extracting.
ArrayRef<Value *> UserIgnoreList;
// Number of load-bundles, which contain consecutive loads.
int NumLoadsWantToKeepOrder;
// Number of load-bundles of size 2, which are consecutive loads if reversed.
int NumLoadsWantToChangeOrder;
// Analysis and block reference.
Function *F;
ScalarEvolution *SE;
@ -879,12 +887,21 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth) {
// Check if the loads are consecutive or of we need to swizzle them.
for (unsigned i = 0, e = VL.size() - 1; i < e; ++i) {
LoadInst *L = cast<LoadInst>(VL[i]);
if (!L->isSimple() || !isConsecutiveAccess(VL[i], VL[i + 1])) {
if (!L->isSimple()) {
newTreeEntry(VL, false);
DEBUG(dbgs() << "SLP: Need to swizzle loads.\n");
DEBUG(dbgs() << "SLP: Gathering non-simple loads.\n");
return;
}
if (!isConsecutiveAccess(VL[i], VL[i + 1])) {
if (VL.size() == 2 && isConsecutiveAccess(VL[1], VL[0])) {
++NumLoadsWantToChangeOrder;
}
newTreeEntry(VL, false);
DEBUG(dbgs() << "SLP: Gathering non-consecutive loads.\n");
return;
}
}
++NumLoadsWantToKeepOrder;
newTreeEntry(VL, true);
DEBUG(dbgs() << "SLP: added a vector of loads.\n");
return;
@ -2237,15 +2254,15 @@ private:
unsigned collectStores(BasicBlock *BB, BoUpSLP &R);
/// \brief Try to vectorize a chain that starts at two arithmetic instrs.
bool tryToVectorizePair(Value *A, Value *B, BoUpSLP &R,
BinaryOperator *V = nullptr);
bool tryToVectorizePair(Value *A, Value *B, BoUpSLP &R);
/// \brief Try to vectorize a list of operands.
/// \@param BuildVector A list of users to ignore for the purpose of
/// scheduling and that don't need extracting.
/// \returns true if a value was vectorized.
bool tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R,
ArrayRef<Value *> BuildVector = None);
ArrayRef<Value *> BuildVector = None,
bool allowReorder = false);
/// \brief Try to vectorize a chain that may start at the operands of \V;
bool tryToVectorize(BinaryOperator *V, BoUpSLP &R);
@ -2411,28 +2428,16 @@ unsigned SLPVectorizer::collectStores(BasicBlock *BB, BoUpSLP &R) {
return count;
}
bool SLPVectorizer::tryToVectorizePair(Value *A, Value *B, BoUpSLP &R,
BinaryOperator *V) {
bool SLPVectorizer::tryToVectorizePair(Value *A, Value *B, BoUpSLP &R) {
if (!A || !B)
return false;
Value *VL[] = { A, B };
// Canonicalize operands based on source order, so that the ordering in the
// expression tree more closely matches the ordering of the source.
if (V && V->isCommutative() && isa<Instruction>(A) && isa<Instruction>(B) &&
cast<Instruction>(A)->getParent() == cast<Instruction>(B)->getParent()) {
assert(V->getOperand(0) == A && V->getOperand(1) == B &&
"Expected operands in order.");
int IndexA = R.getIndex(cast<Instruction>(A));
int IndexB = R.getIndex(cast<Instruction>(B));
if (IndexA > IndexB)
std::swap(VL[0], VL[1]);
}
return tryToVectorizeList(VL, R);
return tryToVectorizeList(VL, R, None, true);
}
bool SLPVectorizer::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R,
ArrayRef<Value *> BuildVector) {
ArrayRef<Value *> BuildVector,
bool allowReorder) {
if (VL.size() < 2)
return false;
@ -2487,6 +2492,14 @@ bool SLPVectorizer::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R,
BuildVectorSlice = BuildVector.slice(i, OpsWidth);
R.buildTree(Ops, BuildVectorSlice);
// TODO: check if we can allow reordering also for other cases than
// tryToVectorizePair()
if (allowReorder && R.shouldReorder()) {
assert(Ops.size() == 2);
assert(BuildVectorSlice.empty());
Value *ReorderedOps[] = { Ops[1], Ops[0] };
R.buildTree(ReorderedOps, None);
}
int Cost = R.getTreeCost();
if (Cost < -SLPCostThreshold) {
@ -2528,7 +2541,7 @@ bool SLPVectorizer::tryToVectorize(BinaryOperator *V, BoUpSLP &R) {
return false;
// Try to vectorize V.
if (tryToVectorizePair(V->getOperand(0), V->getOperand(1), R, V))
if (tryToVectorizePair(V->getOperand(0), V->getOperand(1), R))
return true;
BinaryOperator *A = dyn_cast<BinaryOperator>(V->getOperand(0));
@ -3039,7 +3052,7 @@ bool SLPVectorizer::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
for (int i = 0; i < 2; ++i) {
if (BinaryOperator *BI = dyn_cast<BinaryOperator>(CI->getOperand(i))) {
if (tryToVectorizePair(BI->getOperand(0), BI->getOperand(1), R, BI)) {
if (tryToVectorizePair(BI->getOperand(0), BI->getOperand(1), R)) {
Changed = true;
// We would like to start over since some instructions are deleted
// and the iterator may become invalid value.