Index: include/llvm/CodeGen/BasicTTIImpl.h =================================================================== --- include/llvm/CodeGen/BasicTTIImpl.h +++ include/llvm/CodeGen/BasicTTIImpl.h @@ -504,6 +504,19 @@ unsigned getMaxInterleaveFactor(unsigned VF) { return 1; } + bool isArithmeticDivFast( + unsigned Opcode, Type *Ty, + TTI::OperandValueKind Opd1Info = TTI::OK_AnyValue, + TTI::OperandValueKind Opd2Info = TTI::OK_AnyValue) { + const TargetLoweringBase *TLI = getTLI(); + if (Opd2Info == TargetTransformInfo::OK_UniformConstantValue) { + auto VT = TLI->getValueType(DL, Ty); + return TLI->isOperationLegalOrCustom(ISD::MULHU, VT) + || TLI->isOperationLegalOrCustom(ISD::SMUL_LOHI, VT); + } + return false; + } + unsigned getArithmeticInstrCost( unsigned Opcode, Type *Ty, TTI::OperandValueKind Opd1Info = TTI::OK_AnyValue, Index: lib/Target/AArch64/AArch64TargetTransformInfo.cpp =================================================================== --- lib/Target/AArch64/AArch64TargetTransformInfo.cpp +++ lib/Target/AArch64/AArch64TargetTransformInfo.cpp @@ -520,6 +520,27 @@ } LLVM_FALLTHROUGH; case ISD::UDIV: + if (Opd2Info == TargetTransformInfo::OK_UniformConstantValue) { + if (BaseT::isArithmeticDivFast(Opcode, Ty, Opd1Info, Opd2Info)) { + // Vector signed division by constant are expanded to the + // sequence MULHS + ADD/SUB + SRA + SRL + ADD, and unsigned division + // to MULHS + SUB + SRL + ADD + SRL. + int MulCost = getArithmeticInstrCost(Instruction::Mul, Ty, Opd1Info, + Opd2Info, + TargetTransformInfo::OP_None, + TargetTransformInfo::OP_None); + int AddCost = getArithmeticInstrCost(Instruction::Add, Ty, Opd1Info, + Opd2Info, + TargetTransformInfo::OP_None, + TargetTransformInfo::OP_None); + int ShrCost = getArithmeticInstrCost(Instruction::AShr, Ty, Opd1Info, + Opd2Info, + TargetTransformInfo::OP_None, + TargetTransformInfo::OP_None); + return MulCost * 2 + AddCost * 2 + ShrCost * 2 + 1; + } + } + Cost += BaseT::getArithmeticInstrCost(Opcode, Ty, Opd1Info, Opd2Info, Opd1PropInfo, Opd2PropInfo); if (Ty->isVectorTy()) { Index: test/Analysis/CostModel/AArch64/div_cte.ll =================================================================== --- /dev/null +++ test/Analysis/CostModel/AArch64/div_cte.ll @@ -0,0 +1,45 @@ +; RUN: opt -cost-model -analyze -mtriple=aarch64-linux-gnu -mattr=+neon < %s | FileCheck %s + +; Verify the cost of integer division by constant. + +define <16 x i8> @sdiv8xi16(<16 x i8> %x) { +; CHECK-LABEL: 'Cost Model Analysis' for function 'sdiv8xi16': +; CHECK: Found an estimated cost of 9 for instruction: %div = sdiv <16 x i8> %x, + %div = sdiv <16 x i8> %x, + ret <16 x i8> %div +} + +define <8 x i16> @sdiv16xi8(<8 x i16> %x) { +; CHECK-LABEL: 'Cost Model Analysis' for function 'sdiv16xi8': +; CHECK: Found an estimated cost of 9 for instruction: %div = sdiv <8 x i16> %x, + %div = sdiv <8 x i16> %x, + ret <8 x i16> %div +} + +define <4 x i32> @sdiv32xi4(<4 x i32> %x) { +; CHECK-LABEL: 'Cost Model Analysis' for function 'sdiv32xi4': +; CHECK: Found an estimated cost of 9 for instruction: %div = sdiv <4 x i32> %x, + %div = sdiv <4 x i32> %x, + ret <4 x i32> %div +} + +define <16 x i8> @udiv8xi16(<16 x i8> %x) { +; CHECK-LABEL: 'Cost Model Analysis' for function 'udiv8xi16': +; CHECK: Found an estimated cost of 9 for instruction: %div = udiv <16 x i8> %x, + %div = udiv <16 x i8> %x, + ret <16 x i8> %div +} + +define <8 x i16> @udiv16xi8(<8 x i16> %x) { +; CHECK-LABEL: 'Cost Model Analysis' for function 'udiv16xi8': +; CHECK: Found an estimated cost of 9 for instruction: %div = udiv <8 x i16> %x, + %div = udiv <8 x i16> %x, + ret <8 x i16> %div +} + +define <4 x i32> @udiv32xi4(<4 x i32> %x) { +; CHECK-LABEL: Printing analysis 'Cost Model Analysis' for function 'udiv32xi4': +; CHECK: Found an estimated cost of 9 for instruction: %div = udiv <4 x i32> %x, + %div = udiv <4 x i32> %x, + ret <4 x i32> %div +}