Skip to content

[DirectX] Add isinf f16 emulation for SM6.8 and lower #156932

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 4 commits into from
Sep 5, 2025
Merged

[DirectX] Add isinf f16 emulation for SM6.8 and lower #156932

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
8c31865
[DirectX] Add isinf f16 emulation for SM6.8 and lower
farzonl Sep 4, 2025
3520bb3
update test case.
farzonl Sep 4, 2025
c748fdd
update unit test
farzonl Sep 4, 2025
9133b5e
address pr comments
farzonl Sep 5, 2025
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
3 changes: 3 additions & 0 deletions clang/lib/Driver/ToolChains/HLSL.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -132,6 +132,9 @@ std::optional<std::string> tryParseProfile(StringRef Profile) {
case 8:
SubArch = llvm::Triple::DXILSubArch_v1_8;
break;
case 9:
SubArch = llvm::Triple::DXILSubArch_v1_9;
break;
case OfflineLibMinor:
// Always consider minor version x as the latest supported DXIL version
SubArch = llvm::Triple::LatestDXILSubArch;
Expand Down
2 changes: 1 addition & 1 deletion clang/unittests/Driver/DXCModeTest.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -85,7 +85,7 @@ TEST(DxcModeTest, TargetProfileValidation) {
InMemoryFileSystem, Diags);
validateTargetProfile("-Tcs_6_8", "dxilv1.8--shadermodel6.8-compute",
InMemoryFileSystem, Diags);
validateTargetProfile("-Tlib_6_x", "dxilv1.8--shadermodel6.15-library",
validateTargetProfile("-Tlib_6_x", "dxilv1.9--shadermodel6.15-library",
InMemoryFileSystem, Diags);

// Invalid tests.
Expand Down
3 changes: 2 additions & 1 deletion llvm/include/llvm/TargetParser/Triple.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -180,7 +180,8 @@ class Triple {
DXILSubArch_v1_6,
DXILSubArch_v1_7,
DXILSubArch_v1_8,
LatestDXILSubArch = DXILSubArch_v1_8,
DXILSubArch_v1_9,
LatestDXILSubArch = DXILSubArch_v1_9,
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

i'm not familiar with this code. What is the effect of the latestdxilsubarch? is it ok to set it to 1.9?

Copy link
Member Author

@farzonl farzonl Sep 5, 2025 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

LatestDXILSubArch must always match the latest dxil version. Its uses for the 6.x target triple format.

};
enum VendorType {
UnknownVendor,
Expand Down
42 changes: 41 additions & 1 deletion llvm/lib/Target/DirectX/DXILIntrinsicExpansion.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,41 @@ static bool resourceAccessNeeds64BitExpansion(Module *M, Type *OverloadTy,
return ScalarTy->isDoubleTy() || ScalarTy->isIntegerTy(64);
}

static Value *expand16BitIsInf(CallInst *Orig) {
Module *M = Orig->getModule();
if (M->getTargetTriple().getDXILVersion() >= VersionTuple(1, 9))
return nullptr;

Value *Val = Orig->getOperand(0);
Type *ValTy = Val->getType();
if (!ValTy->getScalarType()->isHalfTy())
return nullptr;

IRBuilder<> Builder(Orig);
Type *IType = Type::getInt16Ty(M->getContext());
Constant *PosInf =
ValTy->isVectorTy()
? ConstantVector::getSplat(
ElementCount::getFixed(
cast<FixedVectorType>(ValTy)->getNumElements()),
ConstantInt::get(IType, 0x7c00))
: ConstantInt::get(IType, 0x7c00);

Constant *NegInf =
ValTy->isVectorTy()
? ConstantVector::getSplat(
ElementCount::getFixed(
cast<FixedVectorType>(ValTy)->getNumElements()),
ConstantInt::get(IType, 0xfc00))
: ConstantInt::get(IType, 0xfc00);

Value *IVal = Builder.CreateBitCast(Val, PosInf->getType());
Value *B1 = Builder.CreateICmpEQ(IVal, PosInf);
Value *B2 = Builder.CreateICmpEQ(IVal, NegInf);
Value *B3 = Builder.CreateOr(B1, B2);
return B3;
}

static bool isIntrinsicExpansion(Function &F) {
switch (F.getIntrinsicID()) {
case Intrinsic::abs:
Expand All @@ -68,6 +103,7 @@ static bool isIntrinsicExpansion(Function &F) {
case Intrinsic::dx_sclamp:
case Intrinsic::dx_nclamp:
case Intrinsic::dx_degrees:
case Intrinsic::dx_isinf:
case Intrinsic::dx_lerp:
case Intrinsic::dx_normalize:
case Intrinsic::dx_fdot:
Expand Down Expand Up @@ -301,9 +337,10 @@ static Value *expandIsFPClass(CallInst *Orig) {
auto *TCI = dyn_cast<ConstantInt>(T);

// These FPClassTest cases have DXIL opcodes, so they will be handled in
// DXIL Op Lowering instead.
// DXIL Op Lowering instead for all non f16 cases.
switch (TCI->getZExtValue()) {
case FPClassTest::fcInf:
return expand16BitIsInf(Orig);
case FPClassTest::fcNan:
case FPClassTest::fcNormal:
case FPClassTest::fcFinite:
Expand Down Expand Up @@ -873,6 +910,9 @@ static bool expandIntrinsic(Function &F, CallInst *Orig) {
case Intrinsic::dx_degrees:
Result = expandDegreesIntrinsic(Orig);
break;
case Intrinsic::dx_isinf:
Result = expand16BitIsInf(Orig);
break;
case Intrinsic::dx_lerp:
Result = expandLerpIntrinsic(Orig);
break;
Expand Down
9 changes: 8 additions & 1 deletion llvm/lib/TargetParser/Triple.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -158,6 +158,8 @@ StringRef Triple::getArchName(ArchType Kind, SubArchType SubArch) {
return "dxilv1.7";
case Triple::DXILSubArch_v1_8:
return "dxilv1.8";
case Triple::DXILSubArch_v1_9:
return "dxilv1.9";
default:
break;
}
Expand Down Expand Up @@ -650,6 +652,8 @@ static Triple::ArchType parseArch(StringRef ArchName) {
.Cases("dxil", "dxilv1.0", "dxilv1.1", "dxilv1.2", "dxilv1.3",
"dxilv1.4", "dxilv1.5", "dxilv1.6", "dxilv1.7",
"dxilv1.8", Triple::dxil)
// Note: Cases has max limit of 10.
.Case("dxilv1.9", Triple::dxil)
.Case("xtensa", Triple::xtensa)
.Default(Triple::UnknownArch);

Expand Down Expand Up @@ -842,6 +846,7 @@ static Triple::SubArchType parseSubArch(StringRef SubArchName) {
.EndsWith("v1.6", Triple::DXILSubArch_v1_6)
.EndsWith("v1.7", Triple::DXILSubArch_v1_7)
.EndsWith("v1.8", Triple::DXILSubArch_v1_8)
.EndsWith("v1.9", Triple::DXILSubArch_v1_9)
.Default(Triple::NoSubArch);

StringRef ARMSubArch = ARM::getCanonicalArchName(SubArchName);
Expand Down Expand Up @@ -1111,7 +1116,7 @@ static StringRef getDXILArchNameFromShaderModel(StringRef ShaderModelStr) {
VersionTuple Ver =
parseVersionFromName(ShaderModelStr.drop_front(strlen("shadermodel")));
// Default DXIL minor version when Shader Model version is anything other
// than 6.[0...8] or 6.x (which translates to latest current SM version)
// than 6.[0...9] or 6.x (which translates to latest current SM version)
const unsigned SMMajor = 6;
if (!Ver.empty()) {
if (Ver.getMajor() == SMMajor) {
Expand All @@ -1135,6 +1140,8 @@ static StringRef getDXILArchNameFromShaderModel(StringRef ShaderModelStr) {
return Triple::getArchName(Triple::dxil, Triple::DXILSubArch_v1_7);
case 8:
return Triple::getArchName(Triple::dxil, Triple::DXILSubArch_v1_8);
case 9:
return Triple::getArchName(Triple::dxil, Triple::DXILSubArch_v1_9);
default:
report_fatal_error("Unsupported Shader Model version", false);
}
Expand Down
21 changes: 19 additions & 2 deletions llvm/test/CodeGen/DirectX/is_fpclass.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt -S -dxil-intrinsic-expansion -scalarizer -dxil-op-lower -mtriple=dxil-pc-shadermodel6.3-library %s | FileCheck %s
; RUN: opt -S -dxil-intrinsic-expansion -scalarizer -dxil-op-lower -mtriple=dxil-pc-shadermodel6.9-library %s | FileCheck %s --check-prefixes=CHECK,SM69CHECK
; RUN: opt -S -dxil-intrinsic-expansion -scalarizer -dxil-op-lower -mtriple=dxil-pc-shadermodel6.8-library %s | FileCheck %s --check-prefixes=CHECK,SMOLDCHECK


define noundef i1 @isnegzero(float noundef %a) {
Expand Down Expand Up @@ -75,6 +75,23 @@ entry:
ret i1 %0
}

define noundef i1 @isinfh(half noundef %a) {
; CHECK-LABEL: define noundef i1 @isinfh(
; CHECK-SAME: half noundef [[A:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; SM69CHECK-NEXT: [[ISINF:%.*]] = call i1 @dx.op.isSpecialFloat.f16(i32 9, half [[A]]) #[[ATTR0]]
; SMOLDCHECK-NEXT: [[BITCAST:%.*]] = bitcast half %a to i16
; SMOLDCHECK-NEXT: [[CMPHIGH:%.*]] = icmp eq i16 [[BITCAST]], 31744
; SMOLDCHECK-NEXT: [[CMPLOW:%.*]] = icmp eq i16 [[BITCAST]], -1024
; SMOLDCHECK-NEXT: [[OR:%.*]] = or i1 [[CMPHIGH]], [[CMPLOW]]
; SMOLDCHECK-NEXT: ret i1 [[OR]]
; SM69CHECK-NEXT: ret i1 [[ISINF]]
;
entry:
%0 = call i1 @llvm.is.fpclass.f16(half %a, i32 516)
ret i1 %0
}

define noundef <2 x i1> @isinfv2(<2 x float> noundef %a) {
; CHECK-LABEL: define noundef <2 x i1> @isinfv2(
; CHECK-SAME: <2 x float> noundef [[A:%.*]]) {
Expand Down
43 changes: 37 additions & 6 deletions llvm/test/CodeGen/DirectX/isinf.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
; RUN: opt -S -scalarizer -dxil-op-lower -mtriple=dxil-pc-shadermodel6.3-library %s | FileCheck %s
; RUN: opt -S -dxil-intrinsic-expansion -scalarizer -dxil-op-lower -mtriple=dxil-pc-shadermodel6.9-library %s | FileCheck %s --check-prefixes=CHECK,SM69CHECK
; RUN: opt -S -dxil-intrinsic-expansion -scalarizer -dxil-op-lower -mtriple=dxil-pc-shadermodel6.8-library %s | FileCheck %s --check-prefixes=CHECK,SMOLDCHECK

; Make sure dxil operation function calls for isinf are generated for float and half.

Expand All @@ -11,17 +12,47 @@ entry:

define noundef i1 @isinf_half(half noundef %a) {
entry:
; CHECK: call i1 @dx.op.isSpecialFloat.f16(i32 9, half %{{.*}}) #[[#ATTR]]
; SM69CHECK: call i1 @dx.op.isSpecialFloat.f16(i32 9, half %{{.*}}) #[[#ATTR]]
; SMOLDCHECK: [[BITCAST:%.*]] = bitcast half %a to i16
; SMOLDCHECK: [[CMPHIGH:%.*]] = icmp eq i16 [[BITCAST]], 31744
; SMOLDCHECK: [[CMPLOW:%.*]] = icmp eq i16 [[BITCAST]], -1024
; SMOLDCHECK: [[OR:%.*]] = or i1 [[CMPHIGH]], [[CMPLOW]]
%dx.isinf = call i1 @llvm.dx.isinf.f16(half %a)
ret i1 %dx.isinf
}

define noundef <4 x i1> @isinf_half4(<4 x half> noundef %p0) {
entry:
; CHECK: call i1 @dx.op.isSpecialFloat.f16(i32 9, half
; CHECK: call i1 @dx.op.isSpecialFloat.f16(i32 9, half
; CHECK: call i1 @dx.op.isSpecialFloat.f16(i32 9, half
; CHECK: call i1 @dx.op.isSpecialFloat.f16(i32 9, half
; SM69CHECK: call i1 @dx.op.isSpecialFloat.f16(i32 9, half
; SM69CHECK: call i1 @dx.op.isSpecialFloat.f16(i32 9, half
; SM69CHECK: call i1 @dx.op.isSpecialFloat.f16(i32 9, half
; SM69CHECK: call i1 @dx.op.isSpecialFloat.f16(i32 9, half

; SMOLDCHECK: [[ee0:%.*]] = extractelement <4 x half> %p0, i64 0
; SMOLDCHECK: [[BITCAST0:%.*]] = bitcast half [[ee0]] to i16
; SMOLDCHECK: [[ee1:%.*]] = extractelement <4 x half> %p0, i64 1
; SMOLDCHECK: [[BITCAST1:%.*]] = bitcast half [[ee1]] to i16
; SMOLDCHECK:[[ee2:%.*]] = extractelement <4 x half> %p0, i64 2
; SMOLDCHECK: [[BITCAST2:%.*]] = bitcast half [[ee2]] to i16
; SMOLDCHECK: [[ee3:%.*]] = extractelement <4 x half> %p0, i64 3
; SMOLDCHECK: [[BITCAST3:%.*]] = bitcast half [[ee3]] to i16
; SMOLDCHECK: [[ICMPHIGH0:%.*]] = icmp eq i16 [[BITCAST0]], 31744
; SMOLDCHECK: [[ICMPHIGH1:%.*]] = icmp eq i16 [[BITCAST1]], 31744
; SMOLDCHECK: [[ICMPHIGH2:%.*]] = icmp eq i16 [[BITCAST2]], 31744
; SMOLDCHECK: [[ICMPHIGH3:%.*]] = icmp eq i16 [[BITCAST3]], 31744
; SMOLDCHECK: [[ICMPLOW0:%.*]] = icmp eq i16 [[BITCAST0]], -1024
; SMOLDCHECK: [[ICMPLOW1:%.*]] = icmp eq i16 [[BITCAST1]], -1024
; SMOLDCHECK: [[ICMPLOW2:%.*]] = icmp eq i16 [[BITCAST2]], -1024
; SMOLDCHECK: [[ICMPLOW3:%.*]] = icmp eq i16 [[BITCAST3]], -1024
; SMOLDCHECK: [[OR0:%.*]] = or i1 [[ICMPHIGH0]], [[ICMPLOW0]]
; SMOLDCHECK: [[OR1:%.*]] = or i1 [[ICMPHIGH1]], [[ICMPLOW1]]
; SMOLDCHECK: [[OR2:%.*]] = or i1 [[ICMPHIGH2]], [[ICMPLOW2]]
; SMOLDCHECK: [[OR3:%.*]] = or i1 [[ICMPHIGH3]], [[ICMPLOW3]]
; SMOLDCHECK: %.upto019 = insertelement <4 x i1> poison, i1 [[OR0]], i64 0
; SMOLDCHECK: %.upto120 = insertelement <4 x i1> %.upto019, i1 [[OR1]], i64 1
; SMOLDCHECK: %.upto221 = insertelement <4 x i1> %.upto120, i1 [[OR2]], i64 2
; SMOLDCHECK: %0 = insertelement <4 x i1> %.upto221, i1 [[OR3]], i64 3

%hlsl.isinf = call <4 x i1> @llvm.dx.isinf.v4f16(<4 x half> %p0)
ret <4 x i1> %hlsl.isinf
}
Expand Down
17 changes: 15 additions & 2 deletions llvm/unittests/TargetParser/TripleTest.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -553,6 +553,13 @@ TEST(TripleTest, ParsedIDs) {
EXPECT_EQ(Triple::ShaderModel, T.getOS());
EXPECT_EQ(VersionTuple(1, 8), T.getDXILVersion());

T = Triple("dxilv1.9-unknown-shadermodel6.15-library");
EXPECT_EQ(Triple::dxil, T.getArch());
EXPECT_EQ(Triple::DXILSubArch_v1_9, T.getSubArch());
EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
EXPECT_EQ(Triple::ShaderModel, T.getOS());
EXPECT_EQ(VersionTuple(1, 9), T.getDXILVersion());

T = Triple("x86_64-unknown-fuchsia");
EXPECT_EQ(Triple::x86_64, T.getArch());
EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
Expand Down Expand Up @@ -1270,6 +1277,12 @@ TEST(TripleTest, ParsedIDs) {
EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
EXPECT_EQ(Triple::UnknownOS, T.getOS());

T = Triple("dxilv1.9-unknown-unknown");
EXPECT_EQ(Triple::dxil, T.getArch());
EXPECT_EQ(Triple::DXILSubArch_v1_9, T.getSubArch());
EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
EXPECT_EQ(Triple::UnknownOS, T.getOS());

// Check specification of unknown SubArch results in
// unknown architecture.
T = Triple("dxilv1.999-unknown-unknown");
Expand Down Expand Up @@ -3226,9 +3239,9 @@ TEST(TripleTest, DXILNormaizeWithVersion) {
Triple::normalize("dxil--shadermodel6.0"));
EXPECT_EQ("dxilv1.1-unknown-shadermodel6.1-library",
Triple::normalize("dxil-shadermodel6.1-unknown-library"));
EXPECT_EQ("dxilv1.8-unknown-shadermodel6.x-unknown",
EXPECT_EQ("dxilv1.9-unknown-shadermodel6.x-unknown",
Triple::normalize("dxil-unknown-shadermodel6.x-unknown"));
EXPECT_EQ("dxilv1.8-unknown-shadermodel6.x-unknown",
EXPECT_EQ("dxilv1.9-unknown-shadermodel6.x-unknown",
Triple::normalize("dxil-unknown-shadermodel6.x-unknown"));
EXPECT_EQ("dxil-unknown-unknown-unknown", Triple::normalize("dxil---"));
EXPECT_EQ("dxilv1.0-pc-shadermodel5.0-compute",
Expand Down