diff options
| -rw-r--r-- | llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 64 | ||||
| -rw-r--r-- | llvm/test/Transforms/LoopVectorize/AArch64/extractvalue-no-scalarization-required.ll | 109 |
2 files changed, 151 insertions, 22 deletions
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp index c1bb43bc5bd..22cf9c7db94 100644 --- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp +++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -1179,7 +1179,7 @@ public: /// VF. Return the cost of the instruction, including scalarization overhead /// if it's needed. The flag NeedToScalarize shows if the call needs to be /// scalarized - - // i.e. either vector version isn't available, or is too expensive. + /// i.e. either vector version isn't available, or is too expensive. unsigned getVectorCallCost(CallInst *CI, unsigned VF, bool &NeedToScalarize); private: @@ -1332,6 +1332,30 @@ private: DecisionList WideningDecisions; + /// Returns true if \p V is expected to be vectorized and it needs to be + /// extracted. + bool needsExtract(Value *V, unsigned VF) const { + Instruction *I = dyn_cast<Instruction>(V); + if (VF == 1 || !I || !TheLoop->contains(I) || TheLoop->isLoopInvariant(I)) + return false; + + // Assume we can vectorize V (and hence we need extraction) if the + // scalars are not computed yet. This can happen, because it is called + // via getScalarizationOverhead from setCostBasedWideningDecision, before + // the scalars are collected. That should be a safe assumption in most + // cases, because we check if the operands have vectorizable types + // beforehand in LoopVectorizationLegality. + return Scalars.find(VF) == Scalars.end() || + !isScalarAfterVectorization(I, VF); + }; + + /// Returns a range containing only operands needing to be extracted. + SmallVector<Value *, 4> filterExtractingOperands(Instruction::op_range Ops, + unsigned VF) { + return SmallVector<Value *, 4>(make_filter_range( + Ops, [this, VF](Value *V) { return this->needsExtract(V, VF); })); + } + public: /// The loop that we evaluate. Loop *TheLoop; @@ -3125,8 +3149,11 @@ unsigned LoopVectorizationCostModel::getVectorIntrinsicCost(CallInst *CI, if (auto *FPMO = dyn_cast<FPMathOperator>(CI)) FMF = FPMO->getFastMathFlags(); - SmallVector<Value *, 4> Operands(CI->arg_operands()); - return TTI.getIntrinsicInstrCost(ID, CI->getType(), Operands, FMF, VF); + // Skip operands that do not require extraction/scalarization and do not incur + // any overhead. + return TTI.getIntrinsicInstrCost( + ID, CI->getType(), filterExtractingOperands(CI->arg_operands(), VF), FMF, + VF); } static Type *smallestIntegerVectorType(Type *T1, Type *T2) { @@ -5346,15 +5373,6 @@ int LoopVectorizationCostModel::computePredInstDiscount( return true; }; - // Returns true if an operand that cannot be scalarized must be extracted - // from a vector. We will account for this scalarization overhead below. Note - // that the non-void predicated instructions are placed in their own blocks, - // and their return values are inserted into vectors. Thus, an extract would - // still be required. - auto needsExtract = [&](Instruction *I) -> bool { - return TheLoop->contains(I) && !isScalarAfterVectorization(I, VF); - }; - // Compute the expected cost discount from scalarizing the entire expression // feeding the predicated instruction. We currently only consider expressions // that are single-use instruction chains. @@ -5394,7 +5412,7 @@ int LoopVectorizationCostModel::computePredInstDiscount( "Instruction has non-scalar type"); if (canBeScalarized(J)) Worklist.push_back(J); - else if (needsExtract(J)) + else if (needsExtract(J, VF)) ScalarCost += TTI.getScalarizationOverhead( ToVectorTy(J->getType(),VF), false, true); } @@ -5684,16 +5702,18 @@ unsigned LoopVectorizationCostModel::getScalarizationOverhead(Instruction *I, if (isa<LoadInst>(I) && !TTI.prefersVectorizedAddressing()) return Cost; - if (CallInst *CI = dyn_cast<CallInst>(I)) { - SmallVector<const Value *, 4> Operands(CI->arg_operands()); - Cost += TTI.getOperandsScalarizationOverhead(Operands, VF); - } else if (!isa<StoreInst>(I) || - !TTI.supportsEfficientVectorElementLoadStore()) { - SmallVector<const Value *, 4> Operands(I->operand_values()); - Cost += TTI.getOperandsScalarizationOverhead(Operands, VF); - } + // Some targets support efficient element stores. + if (isa<StoreInst>(I) && TTI.supportsEfficientVectorElementLoadStore()) + return Cost; - return Cost; + // Collect operands to consider. + CallInst *CI = dyn_cast<CallInst>(I); + Instruction::op_range Ops = CI ? CI->arg_operands() : I->operands(); + + // Skip operands that do not require extraction/scalarization and do not incur + // any overhead. + return Cost + TTI.getOperandsScalarizationOverhead( + filterExtractingOperands(Ops, VF), VF); } void LoopVectorizationCostModel::setCostBasedWideningDecision(unsigned VF) { diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/extractvalue-no-scalarization-required.ll b/llvm/test/Transforms/LoopVectorize/AArch64/extractvalue-no-scalarization-required.ll new file mode 100644 index 00000000000..c3ad5b078ae --- /dev/null +++ b/llvm/test/Transforms/LoopVectorize/AArch64/extractvalue-no-scalarization-required.ll @@ -0,0 +1,109 @@ +; REQUIRES: asserts + +; RUN: opt -loop-vectorize -mtriple=arm64-apple-ios %s -S -debug -disable-output 2>&1 | FileCheck --check-prefix=CM %s +; RUN: opt -loop-vectorize -force-vector-width=2 -force-vector-interleave=1 %s -S | FileCheck --check-prefix=FORCED %s + +; Test case from PR41294. + +; Check scalar cost for extractvalue. The constant and loop invariant operands are free, +; leaving cost 3 for scalarizing the result + 2 for executing the op with VF 2. + +; CM: LV: Scalar loop costs: 7. +; CM: LV: Found an estimated cost of 5 for VF 2 For instruction: %a = extractvalue { i64, i64 } %sv, 0 +; CM-NEXT: LV: Found an estimated cost of 5 for VF 2 For instruction: %b = extractvalue { i64, i64 } %sv, 1 + +; Check that the extractvalue operands are actually free in vector code. + +; FORCED-LABEL: vector.body: ; preds = %vector.body, %vector.ph +; FORCED-NEXT: %index = phi i32 [ 0, %vector.ph ], [ %index.next, %vector.body ] +; FORCED-NEXT: %broadcast.splatinsert = insertelement <2 x i32> undef, i32 %index, i32 0 +; FORCED-NEXT: %broadcast.splat = shufflevector <2 x i32> %broadcast.splatinsert, <2 x i32> undef, <2 x i32> zeroinitializer +; FORCED-NEXT: %induction = add <2 x i32> %broadcast.splat, <i32 0, i32 1> +; FORCED-NEXT: %0 = add i32 %index, 0 +; FORCED-NEXT: %1 = extractvalue { i64, i64 } %sv, 0 +; FORCED-NEXT: %2 = extractvalue { i64, i64 } %sv, 0 +; FORCED-NEXT: %3 = insertelement <2 x i64> undef, i64 %1, i32 0 +; FORCED-NEXT: %4 = insertelement <2 x i64> %3, i64 %2, i32 1 +; FORCED-NEXT: %5 = extractvalue { i64, i64 } %sv, 1 +; FORCED-NEXT: %6 = extractvalue { i64, i64 } %sv, 1 +; FORCED-NEXT: %7 = insertelement <2 x i64> undef, i64 %5, i32 0 +; FORCED-NEXT: %8 = insertelement <2 x i64> %7, i64 %6, i32 1 +; FORCED-NEXT: %9 = getelementptr i64, i64* %dst, i32 %0 +; FORCED-NEXT: %10 = add <2 x i64> %4, %8 +; FORCED-NEXT: %11 = getelementptr i64, i64* %9, i32 0 +; FORCED-NEXT: %12 = bitcast i64* %11 to <2 x i64>* +; FORCED-NEXT: store <2 x i64> %10, <2 x i64>* %12, align 4 +; FORCED-NEXT: %index.next = add i32 %index, 2 +; FORCED-NEXT: %13 = icmp eq i32 %index.next, 0 +; FORCED-NEXT: br i1 %13, label %middle.block, label %vector.body, !llvm.loop !0 + +define void @test1(i64* %dst, {i64, i64} %sv) { +entry: + br label %loop.body + +loop.body: + %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.body ] + %a = extractvalue { i64, i64 } %sv, 0 + %b = extractvalue { i64, i64 } %sv, 1 + %addr = getelementptr i64, i64* %dst, i32 %iv + %add = add i64 %a, %b + store i64 %add, i64* %addr + %iv.next = add nsw i32 %iv, 1 + %cond = icmp ne i32 %iv.next, 0 + br i1 %cond, label %loop.body, label %exit + +exit: + ret void +} + + +; Similar to the test case above, but checks getVectorCallCost as well. +declare float @pow(float, float) readnone nounwind + +; CM: LV: Scalar loop costs: 16. +; CM: LV: Found an estimated cost of 5 for VF 2 For instruction: %a = extractvalue { float, float } %sv, 0 +; CM-NEXT: LV: Found an estimated cost of 5 for VF 2 For instruction: %b = extractvalue { float, float } %sv, 1 + +; FORCED-LABEL: define void @test_getVectorCallCost + +; FORCED-LABEL: vector.body: ; preds = %vector.body, %vector.ph +; FORCED-NEXT: %index = phi i32 [ 0, %vector.ph ], [ %index.next, %vector.body ] +; FORCED-NEXT: %broadcast.splatinsert = insertelement <2 x i32> undef, i32 %index, i32 0 +; FORCED-NEXT: %broadcast.splat = shufflevector <2 x i32> %broadcast.splatinsert, <2 x i32> undef, <2 x i32> zeroinitializer +; FORCED-NEXT: %induction = add <2 x i32> %broadcast.splat, <i32 0, i32 1> +; FORCED-NEXT: %0 = add i32 %index, 0 +; FORCED-NEXT: %1 = extractvalue { float, float } %sv, 0 +; FORCED-NEXT: %2 = extractvalue { float, float } %sv, 0 +; FORCED-NEXT: %3 = insertelement <2 x float> undef, float %1, i32 0 +; FORCED-NEXT: %4 = insertelement <2 x float> %3, float %2, i32 1 +; FORCED-NEXT: %5 = extractvalue { float, float } %sv, 1 +; FORCED-NEXT: %6 = extractvalue { float, float } %sv, 1 +; FORCED-NEXT: %7 = insertelement <2 x float> undef, float %5, i32 0 +; FORCED-NEXT: %8 = insertelement <2 x float> %7, float %6, i32 1 +; FORCED-NEXT: %9 = getelementptr float, float* %dst, i32 %0 +; FORCED-NEXT: %10 = call <2 x float> @llvm.pow.v2f32(<2 x float> %4, <2 x float> %8) +; FORCED-NEXT: %11 = getelementptr float, float* %9, i32 0 +; FORCED-NEXT: %12 = bitcast float* %11 to <2 x float>* +; FORCED-NEXT: store <2 x float> %10, <2 x float>* %12, align 4 +; FORCED-NEXT: %index.next = add i32 %index, 2 +; FORCED-NEXT: %13 = icmp eq i32 %index.next, 0 +; FORCED-NEXT: br i1 %13, label %middle.block, label %vector.body, !llvm.loop !4 + +define void @test_getVectorCallCost(float* %dst, {float, float} %sv) { +entry: + br label %loop.body + +loop.body: + %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.body ] + %a = extractvalue { float, float } %sv, 0 + %b = extractvalue { float, float } %sv, 1 + %addr = getelementptr float, float* %dst, i32 %iv + %p = call float @pow(float %a, float %b) + store float %p, float* %addr + %iv.next = add nsw i32 %iv, 1 + %cond = icmp ne i32 %iv.next, 0 + br i1 %cond, label %loop.body, label %exit + +exit: + ret void +} |
