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

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Sep 5, 2025
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[DirectX] Add isinf f16 emulation for SM6.8 and lower #156932

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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
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3 changes: 3 additions & 0 deletions clang/lib/Driver/ToolChains/HLSL.cpp
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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;
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2 changes: 1 addition & 1 deletion clang/unittests/Driver/DXCModeTest.cpp
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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.
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3 changes: 2 additions & 1 deletion llvm/include/llvm/TargetParser/Triple.h
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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,
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i'm not familiar with this code. What is the effect of the latestdxilsubarch? is it ok to set it to 1.9?

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@farzonl farzonl Sep 5, 2025 •
edited
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LatestDXILSubArch must always match the latest dxil version. Its uses for the 6.x target triple format.

};
enum VendorType {
UnknownVendor,
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44 changes: 43 additions & 1 deletion llvm/lib/Target/DirectX/DXILIntrinsicExpansion.cpp
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Expand Up @@ -51,6 +51,43 @@ 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->isHalfTy() ||
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Could you use getScalarType() here to prevent casting the vector?

!ValTy->getScalarType()->isHalfTy()

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random though, are we going to have to update this code when matrix supported is added?

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yeah maybe that would be better getScalarType I think also works on matricies.

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And yeah this whole file will need to be revisited for matricies.

(ValTy->isVectorTy() &&
cast<FixedVectorType>(ValTy)->getElementType()->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 +105,7 @@ 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 +339,10 @@ 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 +912,9 @@ 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;
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9 changes: 8 additions & 1 deletion llvm/lib/TargetParser/Triple.cpp
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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
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@@ -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
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@@ -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
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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