Skip to content

[CostModel][AArch64] Remove promotion cost for SVE bfloat arith supported with +sve-b16b16 #167717

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Nov 17, 2025
+45 −22
Merged

[CostModel][AArch64] Remove promotion cost for SVE bfloat arith supported with +sve-b16b16 #167717

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 8 additions & 2 deletions llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4163,12 +4163,15 @@ InstructionCost AArch64TTIImpl::getScalarizationOverhead(

std::optional<InstructionCost> AArch64TTIImpl::getFP16BF16PromoteCost(
Type *Ty, TTI::TargetCostKind CostKind, TTI::OperandValueInfo Op1Info,
TTI::OperandValueInfo Op2Info, bool IncludeTrunc,
TTI::OperandValueInfo Op2Info, bool IncludeTrunc, bool CanUseSVE,
std::function<InstructionCost(Type *)> InstCost) const {
if (!Ty->getScalarType()->isHalfTy() && !Ty->getScalarType()->isBFloatTy())
return std::nullopt;
if (Ty->getScalarType()->isHalfTy() && ST->hasFullFP16())
return std::nullopt;
if (CanUseSVE && Ty->isScalableTy() && ST->hasSVEB16B16() &&
ST->isNonStreamingSVEorSME2Available())
return std::nullopt;

Type *PromotedTy = Ty->getWithNewType(Type::getFloatTy(Ty->getContext()));
InstructionCost Cost = getCastInstrCost(Instruction::FPExt, PromotedTy, Ty,
Expand Down Expand Up @@ -4210,6 +4213,8 @@ InstructionCost AArch64TTIImpl::getArithmeticInstrCost(
ISD == ISD::FDIV || ISD == ISD::FREM)
if (auto PromotedCost = getFP16BF16PromoteCost(
Ty, CostKind, Op1Info, Op2Info, /*IncludeTrunc=*/true,
// There is not native support for fdiv/frem even with +sve-b16b16.
/*CanUseSVE=*/ISD != ISD::FDIV && ISD != ISD::FREM,
[&](Type *PromotedTy) {
return getArithmeticInstrCost(Opcode, PromotedTy, CostKind,
Op1Info, Op2Info);
Expand Down Expand Up @@ -4624,7 +4629,8 @@ InstructionCost AArch64TTIImpl::getCmpSelInstrCost(
if (Opcode == Instruction::FCmp) {
if (auto PromotedCost = getFP16BF16PromoteCost(
ValTy, CostKind, Op1Info, Op2Info, /*IncludeTrunc=*/false,
[&](Type *PromotedTy) {
// TODO: Consider costing SVE FCMPs.
/*CanUseSVE=*/false, [&](Type *PromotedTy) {
InstructionCost Cost =
getCmpSelInstrCost(Opcode, PromotedTy, CondTy, VecPred,
CostKind, Op1Info, Op2Info);
Expand Down
9 changes: 4 additions & 5 deletions llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -456,11 +456,10 @@ class AArch64TTIImpl final : public BasicTTIImplBase<AArch64TTIImpl> {

/// FP16 and BF16 operations are lowered to fptrunc(op(fpext, fpext) if the
/// architecture features are not present.
std::optional<InstructionCost>
getFP16BF16PromoteCost(Type *Ty, TTI::TargetCostKind CostKind,
TTI::OperandValueInfo Op1Info,
TTI::OperandValueInfo Op2Info, bool IncludeTrunc,
std::function<InstructionCost(Type *)> InstCost) const;
std::optional<InstructionCost> getFP16BF16PromoteCost(
Type *Ty, TTI::TargetCostKind CostKind, TTI::OperandValueInfo Op1Info,
TTI::OperandValueInfo Op2Info, bool IncludeTrunc, bool CanUseSVE,
std::function<InstructionCost(Type *)> InstCost) const;

InstructionCost
getArithmeticReductionCost(unsigned Opcode, VectorType *Ty,
Expand Down
48 changes: 33 additions & 15 deletions llvm/test/Analysis/CostModel/AArch64/sve-arith-fp.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -33,11 +33,17 @@ define void @fadd() {
}

define void @fadd_bf16() {
; CHECK-LABEL: 'fadd_bf16'
; CHECK-NEXT: Cost Model: Found costs of RThru:11 CodeSize:1 Lat:3 SizeLat:1 for: %NXV4BF16 = fadd <vscale x 4 x bfloat> poison, poison
; CHECK-NEXT: Cost Model: Found costs of RThru:27 CodeSize:1 Lat:3 SizeLat:1 for: %NXV8BF16 = fadd <vscale x 8 x bfloat> poison, poison
; CHECK-NEXT: Cost Model: Found costs of RThru:54 CodeSize:1 Lat:3 SizeLat:1 for: %NXV16BF16 = fadd <vscale x 16 x bfloat> poison, poison
; CHECK-NEXT: Cost Model: Found costs of RThru:0 CodeSize:1 Lat:1 SizeLat:1 for: ret void
; CHECK-BASE-LABEL: 'fadd_bf16'
; CHECK-BASE-NEXT: Cost Model: Found costs of RThru:11 CodeSize:1 Lat:3 SizeLat:1 for: %NXV4BF16 = fadd <vscale x 4 x bfloat> poison, poison
; CHECK-BASE-NEXT: Cost Model: Found costs of RThru:27 CodeSize:1 Lat:3 SizeLat:1 for: %NXV8BF16 = fadd <vscale x 8 x bfloat> poison, poison
; CHECK-BASE-NEXT: Cost Model: Found costs of RThru:54 CodeSize:1 Lat:3 SizeLat:1 for: %NXV16BF16 = fadd <vscale x 16 x bfloat> poison, poison
; CHECK-BASE-NEXT: Cost Model: Found costs of RThru:0 CodeSize:1 Lat:1 SizeLat:1 for: ret void
;
; CHECK-BF16-LABEL: 'fadd_bf16'
; CHECK-BF16-NEXT: Cost Model: Found costs of RThru:1 CodeSize:1 Lat:3 SizeLat:1 for: %NXV4BF16 = fadd <vscale x 4 x bfloat> poison, poison
; CHECK-BF16-NEXT: Cost Model: Found costs of RThru:1 CodeSize:1 Lat:3 SizeLat:1 for: %NXV8BF16 = fadd <vscale x 8 x bfloat> poison, poison
; CHECK-BF16-NEXT: Cost Model: Found costs of RThru:2 CodeSize:1 Lat:3 SizeLat:1 for: %NXV16BF16 = fadd <vscale x 16 x bfloat> poison, poison
; CHECK-BF16-NEXT: Cost Model: Found costs of RThru:0 CodeSize:1 Lat:1 SizeLat:1 for: ret void
;
%NXV4BF16 = fadd <vscale x 4 x bfloat> poison, poison
%NXV8BF16 = fadd <vscale x 8 x bfloat> poison, poison
Expand Down Expand Up @@ -76,11 +82,17 @@ define void @fsub() {
}

define void @fsub_bf16() {
; CHECK-LABEL: 'fsub_bf16'
; CHECK-NEXT: Cost Model: Found costs of RThru:11 CodeSize:1 Lat:3 SizeLat:1 for: %NXV4BF16 = fsub <vscale x 4 x bfloat> poison, poison
; CHECK-NEXT: Cost Model: Found costs of RThru:27 CodeSize:1 Lat:3 SizeLat:1 for: %NXV8BF16 = fsub <vscale x 8 x bfloat> poison, poison
; CHECK-NEXT: Cost Model: Found costs of RThru:54 CodeSize:1 Lat:3 SizeLat:1 for: %NXV16BF16 = fsub <vscale x 16 x bfloat> poison, poison
; CHECK-NEXT: Cost Model: Found costs of RThru:0 CodeSize:1 Lat:1 SizeLat:1 for: ret void
; CHECK-BASE-LABEL: 'fsub_bf16'
; CHECK-BASE-NEXT: Cost Model: Found costs of RThru:11 CodeSize:1 Lat:3 SizeLat:1 for: %NXV4BF16 = fsub <vscale x 4 x bfloat> poison, poison
; CHECK-BASE-NEXT: Cost Model: Found costs of RThru:27 CodeSize:1 Lat:3 SizeLat:1 for: %NXV8BF16 = fsub <vscale x 8 x bfloat> poison, poison
; CHECK-BASE-NEXT: Cost Model: Found costs of RThru:54 CodeSize:1 Lat:3 SizeLat:1 for: %NXV16BF16 = fsub <vscale x 16 x bfloat> poison, poison
; CHECK-BASE-NEXT: Cost Model: Found costs of RThru:0 CodeSize:1 Lat:1 SizeLat:1 for: ret void
;
; CHECK-BF16-LABEL: 'fsub_bf16'
; CHECK-BF16-NEXT: Cost Model: Found costs of RThru:1 CodeSize:1 Lat:3 SizeLat:1 for: %NXV4BF16 = fsub <vscale x 4 x bfloat> poison, poison
; CHECK-BF16-NEXT: Cost Model: Found costs of RThru:1 CodeSize:1 Lat:3 SizeLat:1 for: %NXV8BF16 = fsub <vscale x 8 x bfloat> poison, poison
; CHECK-BF16-NEXT: Cost Model: Found costs of RThru:2 CodeSize:1 Lat:3 SizeLat:1 for: %NXV16BF16 = fsub <vscale x 16 x bfloat> poison, poison
; CHECK-BF16-NEXT: Cost Model: Found costs of RThru:0 CodeSize:1 Lat:1 SizeLat:1 for: ret void
;
%NXV4BF16 = fsub <vscale x 4 x bfloat> poison, poison
%NXV8BF16 = fsub <vscale x 8 x bfloat> poison, poison
Expand Down Expand Up @@ -160,11 +172,17 @@ define void @fmul() {
}

define void @fmul_bf16() {
; CHECK-LABEL: 'fmul_bf16'
; CHECK-NEXT: Cost Model: Found costs of RThru:12 CodeSize:1 Lat:3 SizeLat:1 for: %NXV4BF16 = fmul <vscale x 4 x bfloat> poison, poison
; CHECK-NEXT: Cost Model: Found costs of RThru:29 CodeSize:1 Lat:3 SizeLat:1 for: %NXV8BF16 = fmul <vscale x 8 x bfloat> poison, poison
; CHECK-NEXT: Cost Model: Found costs of RThru:58 CodeSize:1 Lat:3 SizeLat:1 for: %NXV16BF16 = fmul <vscale x 16 x bfloat> poison, poison
; CHECK-NEXT: Cost Model: Found costs of RThru:0 CodeSize:1 Lat:1 SizeLat:1 for: ret void
; CHECK-BASE-LABEL: 'fmul_bf16'
; CHECK-BASE-NEXT: Cost Model: Found costs of RThru:12 CodeSize:1 Lat:3 SizeLat:1 for: %NXV4BF16 = fmul <vscale x 4 x bfloat> poison, poison
; CHECK-BASE-NEXT: Cost Model: Found costs of RThru:29 CodeSize:1 Lat:3 SizeLat:1 for: %NXV8BF16 = fmul <vscale x 8 x bfloat> poison, poison
; CHECK-BASE-NEXT: Cost Model: Found costs of RThru:58 CodeSize:1 Lat:3 SizeLat:1 for: %NXV16BF16 = fmul <vscale x 16 x bfloat> poison, poison
; CHECK-BASE-NEXT: Cost Model: Found costs of RThru:0 CodeSize:1 Lat:1 SizeLat:1 for: ret void
;
; CHECK-BF16-LABEL: 'fmul_bf16'
; CHECK-BF16-NEXT: Cost Model: Found costs of RThru:2 CodeSize:1 Lat:3 SizeLat:1 for: %NXV4BF16 = fmul <vscale x 4 x bfloat> poison, poison
; CHECK-BF16-NEXT: Cost Model: Found costs of RThru:2 CodeSize:1 Lat:3 SizeLat:1 for: %NXV8BF16 = fmul <vscale x 8 x bfloat> poison, poison
; CHECK-BF16-NEXT: Cost Model: Found costs of RThru:4 CodeSize:1 Lat:3 SizeLat:1 for: %NXV16BF16 = fmul <vscale x 16 x bfloat> poison, poison
; CHECK-BF16-NEXT: Cost Model: Found costs of RThru:0 CodeSize:1 Lat:1 SizeLat:1 for: ret void
;
%NXV4BF16 = fmul <vscale x 4 x bfloat> poison, poison
%NXV8BF16 = fmul <vscale x 8 x bfloat> poison, poison
Expand Down
Loading