[llvm] r207746 - Revert r205965, which essentially reverts r205018 for the second time.
Rafael Espíndola
rafael.espindola at gmail.com
Thu May 1 07:00:25 PDT 2014
what about checking in the testcase in PR19621?
On 1 May 2014 07:24, Chandler Carruth <chandlerc at gmail.com> wrote:
> Author: chandlerc
> Date: Thu May 1 06:24:11 2014
> New Revision: 207746
>
> URL: http://llvm.org/viewvc/llvm-project?rev=207746&view=rev
> Log:
> Revert r205965, which essentially reverts r205018 for the second time.
> =[
>
> Turns out that this was the root cause of PR19621. We found a crasher
> only recently (likely due to improvements elsewhere in the SLP
> vectorizer) but the reduced test case failed all the way back to here.
> I've confirmed that reverting this patch both fixes the reduced test
> case in PR19621 and the actual source file that led to it, so it seems
> to really be rooted here. I've replied to the commit thread with
> discussion of my (feeble) attempts to debug this. Didn't make it very
> far, so reverting now that we have a good test case so that things can
> get back to healthy while the debugging carries on.
>
> Modified:
> llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp
> llvm/trunk/test/Transforms/SLPVectorizer/X86/insert-element-build-vector.ll
>
> Modified: llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp?rev=207746&r1=207745&r2=207746&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp (original)
> +++ llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp Thu May 1 06:24:11 2014
> @@ -366,13 +366,13 @@ public:
> /// A negative number means that this is profitable.
> int getTreeCost();
>
> - /// Construct a vectorizable tree that starts at \p Roots, ignoring users for
> - /// the purpose of scheduling and extraction in the \p UserIgnoreLst.
> - void buildTree(ArrayRef<Value *> Roots,
> - ArrayRef<Value *> UserIgnoreLst = None);
> + /// Construct a vectorizable tree that starts at \p Roots and is possibly
> + /// used by a reduction of \p RdxOps.
> + void buildTree(ArrayRef<Value *> Roots, ValueSet *RdxOps = 0);
>
> /// Clear the internal data structures that are created by 'buildTree'.
> void deleteTree() {
> + RdxOps = 0;
> VectorizableTree.clear();
> ScalarToTreeEntry.clear();
> MustGather.clear();
> @@ -528,8 +528,8 @@ private:
> /// Numbers instructions in different blocks.
> DenseMap<BasicBlock *, BlockNumbering> BlocksNumbers;
>
> - /// List of users to ignore during scheduling and that don't need extracting.
> - ArrayRef<Value *> UserIgnoreList;
> + /// Reduction operators.
> + ValueSet *RdxOps;
>
> // Analysis and block reference.
> Function *F;
> @@ -543,10 +543,9 @@ private:
> IRBuilder<> Builder;
> };
>
> -void BoUpSLP::buildTree(ArrayRef<Value *> Roots,
> - ArrayRef<Value *> UserIgnoreLst) {
> +void BoUpSLP::buildTree(ArrayRef<Value *> Roots, ValueSet *Rdx) {
> deleteTree();
> - UserIgnoreList = UserIgnoreLst;
> + RdxOps = Rdx;
> if (!getSameType(Roots))
> return;
> buildTree_rec(Roots, 0);
> @@ -578,9 +577,8 @@ void BoUpSLP::buildTree(ArrayRef<Value *
> if (!UserInst)
> continue;
>
> - // Ignore users in the user ignore list.
> - if (std::find(UserIgnoreList.begin(), UserIgnoreList.end(), UserInst) !=
> - UserIgnoreList.end())
> + // Ignore uses that are part of the reduction.
> + if (Rdx && std::find(Rdx->begin(), Rdx->end(), UserInst) != Rdx->end())
> continue;
>
> DEBUG(dbgs() << "SLP: Need to extract:" << *U << " from lane " <<
> @@ -711,9 +709,8 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
> continue;
> }
>
> - // Ignore users in the user ignore list.
> - if (std::find(UserIgnoreList.begin(), UserIgnoreList.end(), UI) !=
> - UserIgnoreList.end())
> + // This user is part of the reduction.
> + if (RdxOps && RdxOps->count(UI))
> continue;
>
> // Make sure that we can schedule this unknown user.
> @@ -1752,9 +1749,8 @@ Value *BoUpSLP::vectorizeTree() {
> DEBUG(dbgs() << "SLP: \tvalidating user:" << *U << ".\n");
>
> assert((ScalarToTreeEntry.count(U) ||
> - // It is legal to replace users in the ignorelist by undef.
> - (std::find(UserIgnoreList.begin(), UserIgnoreList.end(), U) !=
> - UserIgnoreList.end())) &&
> + // It is legal to replace the reduction users by undef.
> + (RdxOps && RdxOps->count(U))) &&
> "Replacing out-of-tree value with undef");
> }
> #endif
> @@ -1958,11 +1954,8 @@ private:
> 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);
> + bool tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R);
>
> /// \brief Try to vectorize a chain that may start at the operands of \V;
> bool tryToVectorize(BinaryOperator *V, BoUpSLP &R);
> @@ -2135,8 +2128,7 @@ bool SLPVectorizer::tryToVectorizePair(V
> return tryToVectorizeList(VL, R);
> }
>
> -bool SLPVectorizer::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R,
> - ArrayRef<Value *> BuildVector) {
> +bool SLPVectorizer::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R) {
> if (VL.size() < 2)
> return false;
>
> @@ -2186,33 +2178,13 @@ bool SLPVectorizer::tryToVectorizeList(A
> << "\n");
> ArrayRef<Value *> Ops = VL.slice(i, OpsWidth);
>
> - ArrayRef<Value *> BuildVectorSlice;
> - if (!BuildVector.empty())
> - BuildVectorSlice = BuildVector.slice(i, OpsWidth);
> -
> - R.buildTree(Ops, BuildVectorSlice);
> + R.buildTree(Ops);
> int Cost = R.getTreeCost();
>
> if (Cost < -SLPCostThreshold) {
> DEBUG(dbgs() << "SLP: Vectorizing list at cost:" << Cost << ".\n");
> - Value *VectorizedRoot = R.vectorizeTree();
> + 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()) {
> - Instruction *InsertAfter = cast<Instruction>(VectorizedRoot);
> - for (auto &V : BuildVectorSlice) {
> - InsertElementInst *IE = cast<InsertElementInst>(V);
> - IRBuilder<> Builder(++BasicBlock::iterator(InsertAfter));
> - Instruction *Extract = cast<Instruction>(
> - Builder.CreateExtractElement(VectorizedRoot, IE->getOperand(2)));
> - IE->setOperand(1, Extract);
> - IE->removeFromParent();
> - IE->insertAfter(Extract);
> - InsertAfter = IE;
> - }
> - }
> // Move to the next bundle.
> i += VF - 1;
> Changed = true;
> @@ -2321,7 +2293,7 @@ static Value *createRdxShuffleMask(unsig
> /// *p =
> ///
> class HorizontalReduction {
> - SmallVector<Value *, 16> ReductionOps;
> + SmallPtrSet<Value *, 16> ReductionOps;
> SmallVector<Value *, 32> ReducedVals;
>
> BinaryOperator *ReductionRoot;
> @@ -2415,7 +2387,7 @@ public:
> // We need to be able to reassociate the adds.
> if (!TreeN->isAssociative())
> return false;
> - ReductionOps.push_back(TreeN);
> + ReductionOps.insert(TreeN);
> }
> // Retract.
> Stack.pop_back();
> @@ -2452,7 +2424,7 @@ public:
>
> for (; i < NumReducedVals - ReduxWidth + 1; i += ReduxWidth) {
> ArrayRef<Value *> ValsToReduce(&ReducedVals[i], ReduxWidth);
> - V.buildTree(ValsToReduce, ReductionOps);
> + V.buildTree(ValsToReduce, &ReductionOps);
>
> // Estimate cost.
> int Cost = V.getTreeCost() + getReductionCost(TTI, ReducedVals[i]);
> @@ -2571,16 +2543,13 @@ private:
> ///
> /// Returns true if it matches
> ///
> -static bool findBuildVector(InsertElementInst *FirstInsertElem,
> - SmallVectorImpl<Value *> &BuildVector,
> - SmallVectorImpl<Value *> &BuildVectorOpds) {
> - if (!isa<UndefValue>(FirstInsertElem->getOperand(0)))
> +static bool findBuildVector(InsertElementInst *IE,
> + SmallVectorImpl<Value *> &Ops) {
> + if (!isa<UndefValue>(IE->getOperand(0)))
> return false;
>
> - InsertElementInst *IE = FirstInsertElem;
> while (true) {
> - BuildVector.push_back(IE);
> - BuildVectorOpds.push_back(IE->getOperand(1));
> + Ops.push_back(IE->getOperand(1));
>
> if (IE->use_empty())
> return false;
> @@ -2751,16 +2720,12 @@ bool SLPVectorizer::vectorizeChainsInBlo
> }
>
> // Try to vectorize trees that start at insertelement instructions.
> - if (InsertElementInst *FirstInsertElem = dyn_cast<InsertElementInst>(it)) {
> - SmallVector<Value *, 16> BuildVector;
> - SmallVector<Value *, 16> BuildVectorOpds;
> - if (!findBuildVector(FirstInsertElem, BuildVector, BuildVectorOpds))
> + if (InsertElementInst *IE = dyn_cast<InsertElementInst>(it)) {
> + SmallVector<Value *, 8> Ops;
> + if (!findBuildVector(IE, Ops))
> continue;
>
> - // Vectorize starting with the build vector operands ignoring the
> - // BuildVector instructions for the purpose of scheduling and user
> - // extraction.
> - if (tryToVectorizeList(BuildVectorOpds, R, BuildVector)) {
> + if (tryToVectorizeList(Ops, R)) {
> Changed = true;
> it = BB->begin();
> e = BB->end();
>
> Modified: llvm/trunk/test/Transforms/SLPVectorizer/X86/insert-element-build-vector.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SLPVectorizer/X86/insert-element-build-vector.ll?rev=207746&r1=207745&r2=207746&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/SLPVectorizer/X86/insert-element-build-vector.ll (original)
> +++ llvm/trunk/test/Transforms/SLPVectorizer/X86/insert-element-build-vector.ll Thu May 1 06:24:11 2014
> @@ -195,30 +195,6 @@ define <4 x float> @simple_select_partia
> ret <4 x float> %rb
> }
>
> -; Make sure that vectorization happens even if insertelements operations
> -; must be rescheduled. The case here is from compiling Julia.
> -define <4 x float> @reschedule_extract(<4 x float> %a, <4 x float> %b) {
> -; CHECK-LABEL: @reschedule_extract(
> -; CHECK: %1 = fadd <4 x float> %a, %b
> - %a0 = extractelement <4 x float> %a, i32 0
> - %b0 = extractelement <4 x float> %b, i32 0
> - %c0 = fadd float %a0, %b0
> - %v0 = insertelement <4 x float> undef, float %c0, i32 0
> - %a1 = extractelement <4 x float> %a, i32 1
> - %b1 = extractelement <4 x float> %b, i32 1
> - %c1 = fadd float %a1, %b1
> - %v1 = insertelement <4 x float> %v0, float %c1, i32 1
> - %a2 = extractelement <4 x float> %a, i32 2
> - %b2 = extractelement <4 x float> %b, i32 2
> - %c2 = fadd float %a2, %b2
> - %v2 = insertelement <4 x float> %v1, float %c2, i32 2
> - %a3 = extractelement <4 x float> %a, i32 3
> - %b3 = extractelement <4 x float> %b, i32 3
> - %c3 = fadd float %a3, %b3
> - %v3 = insertelement <4 x float> %v2, float %c3, i32 3
> - ret <4 x float> %v3
> -}
> -
> ; Check that cost model for vectorization takes credit for
> ; instructions that are erased.
> define <4 x float> @take_credit(<4 x float> %a, <4 x float> %b) {
>
>
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