[llvm] r205018 - SLPVectorizer: Ignore users that are insertelements we can reschedule them
Tom Stellard
tom at stellard.net
Mon Mar 31 10:51:36 PDT 2014
On Fri, Mar 28, 2014 at 05:21:23PM -0000, Arnold Schwaighofer wrote:
> Author: arnolds
> Date: Fri Mar 28 12:21:22 2014
> New Revision: 205018
>
> URL: http://llvm.org/viewvc/llvm-project?rev=205018&view=rev
> Log:
> SLPVectorizer: Ignore users that are insertelements we can reschedule them
>
> Patch by Arch D. Robison!
>
This commit causes a crash in the libclc build. To reproduce (see
attached test case):
opt -slp-vectorizer slp-regression.ll -o - -S
-Tom
> 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=205018&r1=205017&r2=205018&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp (original)
> +++ llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp Fri Mar 28 12:21:22 2014
> @@ -365,13 +365,13 @@ public:
> /// A negative number means that this is profitable.
> int getTreeCost();
>
> - /// 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);
> + /// 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);
>
> /// Clear the internal data structures that are created by 'buildTree'.
> void deleteTree() {
> - RdxOps = 0;
> VectorizableTree.clear();
> ScalarToTreeEntry.clear();
> MustGather.clear();
> @@ -527,8 +527,8 @@ private:
> /// Numbers instructions in different blocks.
> DenseMap<BasicBlock *, BlockNumbering> BlocksNumbers;
>
> - /// Reduction operators.
> - ValueSet *RdxOps;
> + /// List of users to ignore during scheduling and that don't need extracting.
> + ArrayRef<Value *> UserIgnoreList;
>
> // Analysis and block reference.
> Function *F;
> @@ -542,9 +542,10 @@ private:
> IRBuilder<> Builder;
> };
>
> -void BoUpSLP::buildTree(ArrayRef<Value *> Roots, ValueSet *Rdx) {
> +void BoUpSLP::buildTree(ArrayRef<Value *> Roots,
> + ArrayRef<Value *> UserIgnoreLst) {
> deleteTree();
> - RdxOps = Rdx;
> + UserIgnoreList = UserIgnoreLst;
> if (!getSameType(Roots))
> return;
> buildTree_rec(Roots, 0);
> @@ -576,8 +577,9 @@ void BoUpSLP::buildTree(ArrayRef<Value *
> if (!UserInst)
> continue;
>
> - // Ignore uses that are part of the reduction.
> - if (Rdx && std::find(Rdx->begin(), Rdx->end(), UserInst) != Rdx->end())
> + // Ignore users in the user ignore list.
> + if (std::find(UserIgnoreList.begin(), UserIgnoreList.end(), UserInst) !=
> + UserIgnoreList.end())
> continue;
>
> DEBUG(dbgs() << "SLP: Need to extract:" << *U << " from lane " <<
> @@ -708,8 +710,9 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
> continue;
> }
>
> - // This user is part of the reduction.
> - if (RdxOps && RdxOps->count(UI))
> + // Ignore users in the user ignore list.
> + if (std::find(UserIgnoreList.begin(), UserIgnoreList.end(), UI) !=
> + UserIgnoreList.end())
> continue;
>
> // Make sure that we can schedule this unknown user.
> @@ -1737,8 +1740,9 @@ Value *BoUpSLP::vectorizeTree() {
> DEBUG(dbgs() << "SLP: \tvalidating user:" << *U << ".\n");
>
> assert((ScalarToTreeEntry.count(U) ||
> - // It is legal to replace the reduction users by undef.
> - (RdxOps && RdxOps->count(U))) &&
> + // It is legal to replace users in the ignorelist by undef.
> + (std::find(UserIgnoreList.begin(), UserIgnoreList.end(), U) !=
> + UserIgnoreList.end())) &&
> "Replacing out-of-tree value with undef");
> }
> #endif
> @@ -1942,8 +1946,11 @@ 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);
> + bool tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R,
> + ArrayRef<Value *> BuildVector = None);
>
> /// \brief Try to vectorize a chain that may start at the operands of \V;
> bool tryToVectorize(BinaryOperator *V, BoUpSLP &R);
> @@ -2116,7 +2123,8 @@ bool SLPVectorizer::tryToVectorizePair(V
> return tryToVectorizeList(VL, R);
> }
>
> -bool SLPVectorizer::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R) {
> +bool SLPVectorizer::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R,
> + ArrayRef<Value *> BuildVector) {
> if (VL.size() < 2)
> return false;
>
> @@ -2166,13 +2174,33 @@ bool SLPVectorizer::tryToVectorizeList(A
> << "\n");
> ArrayRef<Value *> Ops = VL.slice(i, OpsWidth);
>
> - R.buildTree(Ops);
> + ArrayRef<Value *> BuildVectorSlice;
> + if (!BuildVector.empty())
> + BuildVectorSlice = BuildVector.slice(i, OpsWidth);
> +
> + R.buildTree(Ops, BuildVectorSlice);
> int Cost = R.getTreeCost();
>
> if (Cost < -SLPCostThreshold) {
> DEBUG(dbgs() << "SLP: Vectorizing pair at cost:" << Cost << ".\n");
> - R.vectorizeTree();
> + 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()) {
> + 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;
> @@ -2281,7 +2309,7 @@ static Value *createRdxShuffleMask(unsig
> /// *p =
> ///
> class HorizontalReduction {
> - SmallPtrSet<Value *, 16> ReductionOps;
> + SmallVector<Value *, 16> ReductionOps;
> SmallVector<Value *, 32> ReducedVals;
>
> BinaryOperator *ReductionRoot;
> @@ -2375,7 +2403,7 @@ public:
> // We need to be able to reassociate the adds.
> if (!TreeN->isAssociative())
> return false;
> - ReductionOps.insert(TreeN);
> + ReductionOps.push_back(TreeN);
> }
> // Retract.
> Stack.pop_back();
> @@ -2412,7 +2440,7 @@ 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]);
> @@ -2531,13 +2559,16 @@ private:
> ///
> /// Returns true if it matches
> ///
> -static bool findBuildVector(InsertElementInst *IE,
> - SmallVectorImpl<Value *> &Ops) {
> - if (!isa<UndefValue>(IE->getOperand(0)))
> +static bool findBuildVector(InsertElementInst *FirstInsertElem,
> + SmallVectorImpl<Value *> &BuildVector,
> + SmallVectorImpl<Value *> &BuildVectorOpds) {
> + if (!isa<UndefValue>(FirstInsertElem->getOperand(0)))
> return false;
>
> + InsertElementInst *IE = FirstInsertElem;
> while (true) {
> - Ops.push_back(IE->getOperand(1));
> + BuildVector.push_back(IE);
> + BuildVectorOpds.push_back(IE->getOperand(1));
>
> if (IE->use_empty())
> return false;
> @@ -2707,12 +2738,16 @@ bool SLPVectorizer::vectorizeChainsInBlo
> }
>
> // Try to vectorize trees that start at insertelement instructions.
> - if (InsertElementInst *IE = dyn_cast<InsertElementInst>(it)) {
> - SmallVector<Value *, 8> Ops;
> - if (!findBuildVector(IE, Ops))
> + if (InsertElementInst *FirstInsertElem = dyn_cast<InsertElementInst>(it)) {
> + SmallVector<Value *, 16> BuildVector;
> + SmallVector<Value *, 16> BuildVectorOpds;
> + if (!findBuildVector(FirstInsertElem, BuildVector, BuildVectorOpds))
> continue;
>
> - if (tryToVectorizeList(Ops, R)) {
> + // Vectorize starting with the build vector operands ignoring the
> + // BuildVector instructions for the purpose of scheduling and user
> + // extraction.
> + if (tryToVectorizeList(BuildVectorOpds, R, BuildVector)) {
> 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=205018&r1=205017&r2=205018&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 Fri Mar 28 12:21:22 2014
> @@ -194,4 +194,28 @@ 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
> +}
> +
> attributes #0 = { nounwind ssp uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
>
>
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-------------- next part --------------
target datalayout = "e-p:32:32-i64:64-v16:16-v32:32-n16:32:64"
target triple = "nvptx--nvidiacl"
; Function Attrs: alwaysinline nounwind
define <2 x i8> @_Z3clzDv2_c(<2 x i8> %x) #0 {
entry:
%0 = extractelement <2 x i8> %x, i32 0
%call.i = call i8 @llvm.ctlz.i8(i8 %0, i1 false)
%vecinit = insertelement <2 x i8> undef, i8 %call.i, i32 0
%1 = extractelement <2 x i8> %x, i32 1
%call.i4 = call i8 @llvm.ctlz.i8(i8 %1, i1 false)
%vecinit2 = insertelement <2 x i8> %vecinit, i8 %call.i4, i32 1
ret <2 x i8> %vecinit2
}
declare i8 @llvm.ctlz.i8(i8, i1) #3
attributes #0 = { alwaysinline nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { nounwind readnone }
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