Index: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp =================================================================== --- llvm/lib/Transforms/Vectorize/LoopVectorize.cpp +++ llvm/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -7316,10 +7316,37 @@ Type *RetTy = I->getType(); if (canTruncateToMinimalBitwidth(I, VF)) RetTy = IntegerType::get(RetTy->getContext(), MinBWs[I]); - VectorTy = isScalarAfterVectorization(I, VF) ? RetTy : ToVectorTy(RetTy, VF); auto SE = PSE.getSE(); TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput; + auto hasSingleCopyAfterVectorization = [this](Instruction *I, + ElementCount VF) -> bool { + if (VF.isScalar()) + return true; + + auto Scalarized = InstsToScalarize.find(VF); + assert(Scalarized != InstsToScalarize.end() && + "VF not yet analyzed for scalarization profitability"); + return !Scalarized->second.count(I) && + llvm::all_of(I->users(), [&](User *U) { + auto *UI = cast(U); + return !Scalarized->second.count(UI); + }); + }; + + if (isScalarAfterVectorization(I, VF)) { + // With the exception of GEPs and PHIs, after scalarization there should + // only be one copy of the instruction generated in the loop. This is + // because the VF is either 1, or any instructions that need scalarizing + // have already been dealt with by the the time we get here. As a result, + // it means we don't have to multiply the instruction cost by VF. + assert(I->getOpcode() == Instruction::GetElementPtr || + I->getOpcode() == Instruction::PHI || + hasSingleCopyAfterVectorization(I, VF)); + VectorTy = RetTy; + } else + VectorTy = ToVectorTy(RetTy, VF); + // TODO: We need to estimate the cost of intrinsic calls. switch (I->getOpcode()) { case Instruction::GetElementPtr: @@ -7447,21 +7474,16 @@ Op2VK = TargetTransformInfo::OK_UniformValue; SmallVector Operands(I->operand_values()); - unsigned N = isScalarAfterVectorization(I, VF) ? VF.getKnownMinValue() : 1; - return N * TTI.getArithmeticInstrCost( - I->getOpcode(), VectorTy, CostKind, - TargetTransformInfo::OK_AnyValue, - Op2VK, TargetTransformInfo::OP_None, Op2VP, Operands, I); + return TTI.getArithmeticInstrCost( + I->getOpcode(), VectorTy, CostKind, TargetTransformInfo::OK_AnyValue, + Op2VK, TargetTransformInfo::OP_None, Op2VP, Operands, I); } case Instruction::FNeg: { assert(!VF.isScalable() && "VF is assumed to be non scalable."); - unsigned N = isScalarAfterVectorization(I, VF) ? VF.getKnownMinValue() : 1; - return N * TTI.getArithmeticInstrCost( - I->getOpcode(), VectorTy, CostKind, - TargetTransformInfo::OK_AnyValue, - TargetTransformInfo::OK_AnyValue, - TargetTransformInfo::OP_None, TargetTransformInfo::OP_None, - I->getOperand(0), I); + return TTI.getArithmeticInstrCost( + I->getOpcode(), VectorTy, CostKind, TargetTransformInfo::OK_AnyValue, + TargetTransformInfo::OK_AnyValue, TargetTransformInfo::OP_None, + TargetTransformInfo::OP_None, I->getOperand(0), I); } case Instruction::Select: { SelectInst *SI = cast(I); @@ -7605,14 +7627,7 @@ } } - unsigned N; - if (isScalarAfterVectorization(I, VF)) { - assert(!VF.isScalable() && "VF is assumed to be non scalable"); - N = VF.getKnownMinValue(); - } else - N = 1; - return N * - TTI.getCastInstrCost(Opcode, VectorTy, SrcVecTy, CCH, CostKind, I); + return TTI.getCastInstrCost(Opcode, VectorTy, SrcVecTy, CCH, CostKind, I); } case Instruction::Call: { bool NeedToScalarize; @@ -7627,11 +7642,8 @@ case Instruction::ExtractValue: return TTI.getInstructionCost(I, TTI::TCK_RecipThroughput); default: - // The cost of executing VF copies of the scalar instruction. This opcode - // is unknown. Assume that it is the same as 'mul'. - return VF.getKnownMinValue() * TTI.getArithmeticInstrCost( - Instruction::Mul, VectorTy, CostKind) + - getScalarizationOverhead(I, VF); + // This opcode is unknown. Assume that it is the same as 'mul'. + return TTI.getArithmeticInstrCost(Instruction::Mul, VectorTy, CostKind); } // end of switch. } Index: llvm/test/Transforms/LoopVectorize/AArch64/no_vector_instructions.ll =================================================================== --- llvm/test/Transforms/LoopVectorize/AArch64/no_vector_instructions.ll +++ llvm/test/Transforms/LoopVectorize/AArch64/no_vector_instructions.ll @@ -6,7 +6,7 @@ ; CHECK-LABEL: all_scalar ; CHECK: LV: Found scalar instruction: %i.next = add nuw nsw i64 %i, 2 -; CHECK: LV: Found an estimated cost of 2 for VF 2 For instruction: %i.next = add nuw nsw i64 %i, 2 +; CHECK: LV: Found an estimated cost of 1 for VF 2 For instruction: %i.next = add nuw nsw i64 %i, 2 ; CHECK: LV: Not considering vector loop of width 2 because it will not generate any vector instructions ; define void @all_scalar(i64* %a, i64 %n) { Index: llvm/test/Transforms/LoopVectorize/AArch64/predication_costs.ll =================================================================== --- llvm/test/Transforms/LoopVectorize/AArch64/predication_costs.ll +++ llvm/test/Transforms/LoopVectorize/AArch64/predication_costs.ll @@ -86,6 +86,41 @@ ret void } +; CHECK-LABEL: predicated_store_phi +; +; Same as predicate_store except we use a pointer PHI to maintain the address +; +; CHECK: Found new scalar instruction: %addr = phi i32* [ %a, %entry ], [ %addr.next, %for.inc ] +; CHECK: Found new scalar instruction: %addr.next = getelementptr inbounds i32, i32* %addr, i64 1 +; CHECK: Scalarizing and predicating: store i32 %tmp2, i32* %addr, align 4 +; CHECK: Found an estimated cost of 0 for VF 2 For instruction: %addr = phi i32* [ %a, %entry ], [ %addr.next, %for.inc ] +; CHECK: Found an estimated cost of 3 for VF 2 For instruction: store i32 %tmp2, i32* %addr, align 4 +; +define void @predicated_store_phi(i32* %a, i1 %c, i32 %x, i64 %n) { +entry: + br label %for.body + +for.body: + %i = phi i64 [ 0, %entry ], [ %i.next, %for.inc ] + %addr = phi i32 * [ %a, %entry ], [ %addr.next, %for.inc ] + %tmp1 = load i32, i32* %addr, align 4 + %tmp2 = add nsw i32 %tmp1, %x + br i1 %c, label %if.then, label %for.inc + +if.then: + store i32 %tmp2, i32* %addr, align 4 + br label %for.inc + +for.inc: + %i.next = add nuw nsw i64 %i, 1 + %cond = icmp slt i64 %i.next, %n + %addr.next = getelementptr inbounds i32, i32* %addr, i64 1 + br i1 %cond, label %for.body, label %for.end + +for.end: + ret void +} + ; CHECK-LABEL: predicated_udiv_scalarized_operand ; ; This test checks that we correctly compute the cost of the predicated udiv