[clang] [llvm] [DirectX] Implement Shader Flags Analysis for ResMayNotAlias (PR #131070)
Deric C. via llvm-commits
llvm-commits at lists.llvm.org
Fri Mar 14 11:06:58 PDT 2025
https://github.com/Icohedron updated https://github.com/llvm/llvm-project/pull/131070
>From 81196e016dbf1209637dd13315efff7eac461d42 Mon Sep 17 00:00:00 2001
From: Icohedron <cheung.deric at gmail.com>
Date: Fri, 14 Mar 2025 00:24:26 +0000
Subject: [PATCH 1/3] Implement ResMayNotAlias DXIL shader flag analysis
---
clang/include/clang/Basic/CodeGenOptions.def | 3 ++
clang/include/clang/Driver/Options.td | 5 +++
clang/lib/CodeGen/CGHLSLRuntime.cpp | 3 ++
clang/lib/Driver/ToolChains/Clang.cpp | 1 +
clang/test/CodeGenHLSL/res-may-alias.hlsl | 7 +++
llvm/lib/Target/DirectX/DXILShaderFlags.cpp | 43 ++++++++++++++++---
llvm/lib/Target/DirectX/DXILShaderFlags.h | 9 +++-
.../DirectX/ShaderFlags/res-may-alias-0.ll | 39 +++++++++++++++++
.../DirectX/ShaderFlags/res-may-alias-1.ll | 37 ++++++++++++++++
.../res-may-not-alias-shadermodel6.7.ll | 33 ++++++++++++++
.../res-may-not-alias-shadermodel6.8.ll | 33 ++++++++++++++
.../typed-uav-load-additional-formats.ll | 9 ++--
12 files changed, 210 insertions(+), 12 deletions(-)
create mode 100644 clang/test/CodeGenHLSL/res-may-alias.hlsl
create mode 100644 llvm/test/CodeGen/DirectX/ShaderFlags/res-may-alias-0.ll
create mode 100644 llvm/test/CodeGen/DirectX/ShaderFlags/res-may-alias-1.ll
create mode 100644 llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.7.ll
create mode 100644 llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.8.ll
diff --git a/clang/include/clang/Basic/CodeGenOptions.def b/clang/include/clang/Basic/CodeGenOptions.def
index a7f5f1abbb825..a436c0ec98d5b 100644
--- a/clang/include/clang/Basic/CodeGenOptions.def
+++ b/clang/include/clang/Basic/CodeGenOptions.def
@@ -476,6 +476,9 @@ CODEGENOPT(ImportCallOptimization, 1, 0)
/// (BlocksRuntime) on Windows.
CODEGENOPT(StaticClosure, 1, 0)
+/// Assume that UAVs/SRVs may alias
+CODEGENOPT(ResMayAlias, 1, 0)
+
/// FIXME: Make DebugOptions its own top-level .def file.
#include "DebugOptions.def"
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 66ae8f1c7f064..9c5fd2354f95e 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -9043,6 +9043,11 @@ def dxil_validator_version : Option<["/", "-"], "validator-version", KIND_SEPARA
HelpText<"Override validator version for module. Format: <major.minor>;"
"Default: DXIL.dll version or current internal version">,
MarshallingInfoString<TargetOpts<"DxilValidatorVersion">, "\"1.8\"">;
+def res_may_alias : Option<["/", "-"], "res-may-alias", KIND_FLAG>,
+ Group<dxc_Group>, Flags<[HelpHidden]>,
+ Visibility<[DXCOption, ClangOption, CC1Option]>,
+ HelpText<"Assume that UAVs/SRVs may alias">,
+ MarshallingInfoFlag<CodeGenOpts<"ResMayAlias">>;
def target_profile : DXCJoinedOrSeparate<"T">, MetaVarName<"<profile>">,
HelpText<"Set target profile">,
Values<"ps_6_0, ps_6_1, ps_6_2, ps_6_3, ps_6_4, ps_6_5, ps_6_6, ps_6_7,"
diff --git a/clang/lib/CodeGen/CGHLSLRuntime.cpp b/clang/lib/CodeGen/CGHLSLRuntime.cpp
index 5916fa6183a27..6fd8bc295e8ca 100644
--- a/clang/lib/CodeGen/CGHLSLRuntime.cpp
+++ b/clang/lib/CodeGen/CGHLSLRuntime.cpp
@@ -283,10 +283,13 @@ void CGHLSLRuntime::addHLSLBufferLayoutType(const RecordType *StructType,
void CGHLSLRuntime::finishCodeGen() {
auto &TargetOpts = CGM.getTarget().getTargetOpts();
+ auto &CodeGenOpts = CGM.getCodeGenOpts();
llvm::Module &M = CGM.getModule();
Triple T(M.getTargetTriple());
if (T.getArch() == Triple::ArchType::dxil)
addDxilValVersion(TargetOpts.DxilValidatorVersion, M);
+ if (CodeGenOpts.ResMayAlias)
+ M.setModuleFlag(llvm::Module::ModFlagBehavior::Error, "dx.resmayalias", 1);
generateGlobalCtorDtorCalls();
}
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index fe172d923ac07..9be3939641cfc 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -3959,6 +3959,7 @@ static void RenderOpenCLOptions(const ArgList &Args, ArgStringList &CmdArgs,
static void RenderHLSLOptions(const ArgList &Args, ArgStringList &CmdArgs,
types::ID InputType) {
const unsigned ForwardedArguments[] = {options::OPT_dxil_validator_version,
+ options::OPT_res_may_alias,
options::OPT_D,
options::OPT_I,
options::OPT_O,
diff --git a/clang/test/CodeGenHLSL/res-may-alias.hlsl b/clang/test/CodeGenHLSL/res-may-alias.hlsl
new file mode 100644
index 0000000000000..53ee8ee4935d8
--- /dev/null
+++ b/clang/test/CodeGenHLSL/res-may-alias.hlsl
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -res-may-alias -finclude-default-header -triple dxil-pc-shadermodel6.3-library -emit-llvm -disable-llvm-passes -o - %s | FileCheck %s --check-prefix=FLAG
+// RUN: %clang_cc1 -finclude-default-header -triple dxil-pc-shadermodel6.3-library -emit-llvm -disable-llvm-passes -o - %s | FileCheck %s --check-prefix=NOFLAG
+
+// FLAG-DAG: ![[RMA:.*]] = !{i32 1, !"dx.resmayalias", i32 1}
+// FLAG-DAG: !llvm.module.flags = !{{{.*}}![[RMA]]{{.*}}}
+
+// NOFLAG-NOT: dx.resmayalias
diff --git a/llvm/lib/Target/DirectX/DXILShaderFlags.cpp b/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
index 31fbd66dfaa2d..b05ee53798524 100644
--- a/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
+++ b/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
@@ -74,7 +74,8 @@ static bool checkWaveOps(Intrinsic::ID IID) {
/// \param I Instruction to check.
void ModuleShaderFlags::updateFunctionFlags(ComputedShaderFlags &CSF,
const Instruction &I,
- DXILResourceTypeMap &DRTM) {
+ DXILResourceTypeMap &DRTM,
+ const ModuleMetadataInfo &MMDI) {
if (!CSF.Doubles)
CSF.Doubles = I.getType()->isDoubleTy();
@@ -116,8 +117,17 @@ void ModuleShaderFlags::updateFunctionFlags(ComputedShaderFlags &CSF,
switch (II->getIntrinsicID()) {
default:
break;
- case Intrinsic::dx_resource_handlefrombinding:
- switch (DRTM[cast<TargetExtType>(II->getType())].getResourceKind()) {
+ case Intrinsic::dx_resource_handlefrombinding: {
+ dxil::ResourceTypeInfo &RTI = DRTM[cast<TargetExtType>(II->getType())];
+
+ // If -res-may-alias is NOT specified, and DXIL Ver > 1.7.
+ // Then set ResMayNotAlias if function uses UAVs.
+ if (!CSF.ResMayNotAlias && !ResMayAlias &&
+ MMDI.DXILVersion > VersionTuple(1, 7) && RTI.isUAV()) {
+ CSF.ResMayNotAlias = true;
+ }
+
+ switch (RTI.getResourceKind()) {
case dxil::ResourceKind::StructuredBuffer:
case dxil::ResourceKind::RawBuffer:
CSF.EnableRawAndStructuredBuffers = true;
@@ -126,6 +136,7 @@ void ModuleShaderFlags::updateFunctionFlags(ComputedShaderFlags &CSF,
break;
}
break;
+ }
case Intrinsic::dx_resource_load_typedbuffer: {
dxil::ResourceTypeInfo &RTI =
DRTM[cast<TargetExtType>(II->getArgOperand(0)->getType())];
@@ -151,7 +162,17 @@ void ModuleShaderFlags::updateFunctionFlags(ComputedShaderFlags &CSF,
/// Construct ModuleShaderFlags for module Module M
void ModuleShaderFlags::initialize(Module &M, DXILResourceTypeMap &DRTM,
+ DXILBindingMap &DBM,
const ModuleMetadataInfo &MMDI) {
+
+ // Check if -res-may-alias was provided on the command line.
+ // The command line option will set the dx.resmayalias module flag to 1.
+ if (auto *RMA = mdconst::extract_or_null<ConstantInt>(
+ M.getModuleFlag("dx.resmayalias"))) {
+ if (RMA->getValue() != 0)
+ ResMayAlias = true;
+ }
+
CallGraph CG(M);
// Compute Shader Flags Mask for all functions using post-order visit of SCC
@@ -176,10 +197,16 @@ void ModuleShaderFlags::initialize(Module &M, DXILResourceTypeMap &DRTM,
continue;
}
+ // If -res-may-alias is NOT specified, and DXIL Ver <= 1.7.
+ // Then set ResMayNotAlias to true if there are UAVs present globally.
+ if (!ResMayAlias && MMDI.DXILVersion <= VersionTuple(1, 7)) {
+ SCCSF.ResMayNotAlias = !DBM.uavs().empty();
+ }
+
ComputedShaderFlags CSF;
for (const auto &BB : *F)
for (const auto &I : BB)
- updateFunctionFlags(CSF, I, DRTM);
+ updateFunctionFlags(CSF, I, DRTM, MMDI);
// Update combined shader flags mask for all functions in this SCC
SCCSF.merge(CSF);
@@ -249,10 +276,11 @@ AnalysisKey ShaderFlagsAnalysis::Key;
ModuleShaderFlags ShaderFlagsAnalysis::run(Module &M,
ModuleAnalysisManager &AM) {
DXILResourceTypeMap &DRTM = AM.getResult<DXILResourceTypeAnalysis>(M);
+ DXILBindingMap &DBM = AM.getResult<DXILResourceBindingAnalysis>(M);
const ModuleMetadataInfo MMDI = AM.getResult<DXILMetadataAnalysis>(M);
ModuleShaderFlags MSFI;
- MSFI.initialize(M, DRTM, MMDI);
+ MSFI.initialize(M, DRTM, DBM, MMDI);
return MSFI;
}
@@ -282,16 +310,19 @@ PreservedAnalyses ShaderFlagsAnalysisPrinter::run(Module &M,
bool ShaderFlagsAnalysisWrapper::runOnModule(Module &M) {
DXILResourceTypeMap &DRTM =
getAnalysis<DXILResourceTypeWrapperPass>().getResourceTypeMap();
+ DXILBindingMap &DBM =
+ getAnalysis<DXILResourceBindingWrapperPass>().getBindingMap();
const ModuleMetadataInfo MMDI =
getAnalysis<DXILMetadataAnalysisWrapperPass>().getModuleMetadata();
- MSFI.initialize(M, DRTM, MMDI);
+ MSFI.initialize(M, DRTM, DBM, MMDI);
return false;
}
void ShaderFlagsAnalysisWrapper::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequiredTransitive<DXILResourceTypeWrapperPass>();
+ AU.addRequiredTransitive<DXILResourceBindingWrapperPass>();
AU.addRequired<DXILMetadataAnalysisWrapperPass>();
}
diff --git a/llvm/lib/Target/DirectX/DXILShaderFlags.h b/llvm/lib/Target/DirectX/DXILShaderFlags.h
index abf7cc86259ed..1147296d7173c 100644
--- a/llvm/lib/Target/DirectX/DXILShaderFlags.h
+++ b/llvm/lib/Target/DirectX/DXILShaderFlags.h
@@ -28,6 +28,7 @@ namespace llvm {
class Module;
class GlobalVariable;
class DXILResourceTypeMap;
+class DXILBindingMap;
namespace dxil {
@@ -85,11 +86,15 @@ struct ComputedShaderFlags {
struct ModuleShaderFlags {
void initialize(Module &, DXILResourceTypeMap &DRTM,
- const ModuleMetadataInfo &MMDI);
+ DXILBindingMap &DBM, const ModuleMetadataInfo &MMDI);
const ComputedShaderFlags &getFunctionFlags(const Function *) const;
const ComputedShaderFlags &getCombinedFlags() const { return CombinedSFMask; }
private:
+ // A bool to indicate if the -res-may-alias flag was passed to clang-dxc.
+ // A module flag "dx.resmayalias" is set to 1 if true.
+ // This bool is used in the logic for setting the flag ResMayNotAlias.
+ bool ResMayAlias = false;
/// Map of Function-Shader Flag Mask pairs representing properties of each of
/// the functions in the module. Shader Flags of each function represent both
/// module-level and function-level flags
@@ -97,7 +102,7 @@ struct ModuleShaderFlags {
/// Combined Shader Flag Mask of all functions of the module
ComputedShaderFlags CombinedSFMask{};
void updateFunctionFlags(ComputedShaderFlags &, const Instruction &,
- DXILResourceTypeMap &);
+ DXILResourceTypeMap &, const ModuleMetadataInfo &);
};
class ShaderFlagsAnalysis : public AnalysisInfoMixin<ShaderFlagsAnalysis> {
diff --git a/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-alias-0.ll b/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-alias-0.ll
new file mode 100644
index 0000000000000..29901de7f8e37
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-alias-0.ll
@@ -0,0 +1,39 @@
+; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
+
+target triple = "dxil-pc-shadermodel6.8-library"
+
+; CHECK: Combined Shader Flags for Module
+; CHECK-NEXT: Shader Flags Value: 0x200000010
+
+; CHECK: Note: extra DXIL module flags:
+; CHECK: Raw and Structured buffers
+; CHECK: Any UAV may not alias any other UAV
+;
+
+; CHECK: Function loadUAV : 0x20000000
+define float @loadUAV() #0 {
+ %res = call target("dx.TypedBuffer", float, 1, 0, 0)
+ @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
+ %load = call {float, i1} @llvm.dx.resource.load.typedbuffer(
+ target("dx.TypedBuffer", float, 1, 0, 0) %res, i32 0)
+ %val = extractvalue {float, i1} %load, 0
+ ret float %val
+}
+
+; CHECK: Function loadSRV : 0x00000010
+define float @loadSRV() #0 {
+ %res = tail call target("dx.RawBuffer", float, 0, 0)
+ @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
+ %load = call {float, i1} @llvm.dx.resource.load.rawbuffer(
+ target("dx.RawBuffer", float, 0, 0) %res, i32 0, i32 0)
+ %val = extractvalue { float, i1 } %load, 0
+ ret float %val
+}
+
+!llvm.module.flags = !{!0}
+
+; dx.resmayalias should never appear with a value of 0.
+; But if it does, ensure that it has no effect.
+!0 = !{i32 1, !"dx.resmayalias", i32 0}
+
+attributes #0 = { convergent norecurse nounwind "hlsl.export"}
diff --git a/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-alias-1.ll b/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-alias-1.ll
new file mode 100644
index 0000000000000..98a8dd06f6020
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-alias-1.ll
@@ -0,0 +1,37 @@
+; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
+
+target triple = "dxil-pc-shadermodel6.8-library"
+
+; CHECK: Combined Shader Flags for Module
+; CHECK-NEXT: Shader Flags Value: 0x00000010
+
+; CHECK: Note: extra DXIL module flags:
+; CHECK: Raw and Structured buffers
+; CHECK-NOT: Any UAV may not alias any other UAV
+;
+
+; CHECK: Function loadUAV : 0x00000000
+define float @loadUAV() #0 {
+ %res = call target("dx.TypedBuffer", float, 1, 0, 0)
+ @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
+ %load = call {float, i1} @llvm.dx.resource.load.typedbuffer(
+ target("dx.TypedBuffer", float, 1, 0, 0) %res, i32 0)
+ %val = extractvalue {float, i1} %load, 0
+ ret float %val
+}
+
+; CHECK: Function loadSRV : 0x00000010
+define float @loadSRV() #0 {
+ %res = tail call target("dx.RawBuffer", float, 0, 0)
+ @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
+ %load = call {float, i1} @llvm.dx.resource.load.rawbuffer(
+ target("dx.RawBuffer", float, 0, 0) %res, i32 0, i32 0)
+ %val = extractvalue { float, i1 } %load, 0
+ ret float %val
+}
+
+!llvm.module.flags = !{!0}
+
+!0 = !{i32 1, !"dx.resmayalias", i32 1}
+
+attributes #0 = { convergent norecurse nounwind "hlsl.export"}
diff --git a/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.7.ll b/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.7.ll
new file mode 100644
index 0000000000000..ab3eea71bf8f0
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.7.ll
@@ -0,0 +1,33 @@
+; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
+
+target triple = "dxil-pc-shadermodel6.7-library"
+
+; CHECK: Combined Shader Flags for Module
+; CHECK-NEXT: Shader Flags Value: 0x200000010
+
+; CHECK: Note: extra DXIL module flags:
+; CHECK: Raw and Structured buffers
+; CHECK: Any UAV may not alias any other UAV
+;
+
+; CHECK: Function loadUAV : 0x200000000
+define float @loadUAV() #0 {
+ %res = call target("dx.TypedBuffer", float, 1, 0, 0)
+ @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
+ %load = call {float, i1} @llvm.dx.resource.load.typedbuffer(
+ target("dx.TypedBuffer", float, 1, 0, 0) %res, i32 0)
+ %val = extractvalue {float, i1} %load, 0
+ ret float %val
+}
+
+; CHECK: Function loadSRV : 0x200000010
+define float @loadSRV() #0 {
+ %res = tail call target("dx.RawBuffer", float, 0, 0)
+ @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
+ %load = call {float, i1} @llvm.dx.resource.load.rawbuffer(
+ target("dx.RawBuffer", float, 0, 0) %res, i32 0, i32 0)
+ %val = extractvalue { float, i1 } %load, 0
+ ret float %val
+}
+
+attributes #0 = { convergent norecurse nounwind "hlsl.export"}
diff --git a/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.8.ll b/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.8.ll
new file mode 100644
index 0000000000000..fb5e234f0bd93
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.8.ll
@@ -0,0 +1,33 @@
+; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
+
+target triple = "dxil-pc-shadermodel6.8-library"
+
+; CHECK: Combined Shader Flags for Module
+; CHECK-NEXT: Shader Flags Value: 0x200000010
+
+; CHECK: Note: extra DXIL module flags:
+; CHECK: Raw and Structured buffers
+; CHECK: Any UAV may not alias any other UAV
+;
+
+; CHECK: Function loadUAV : 0x20000000
+define float @loadUAV() #0 {
+ %res = call target("dx.TypedBuffer", float, 1, 0, 0)
+ @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
+ %load = call {float, i1} @llvm.dx.resource.load.typedbuffer(
+ target("dx.TypedBuffer", float, 1, 0, 0) %res, i32 0)
+ %val = extractvalue {float, i1} %load, 0
+ ret float %val
+}
+
+; CHECK: Function loadSRV : 0x00000010
+define float @loadSRV() #0 {
+ %res = tail call target("dx.RawBuffer", float, 0, 0)
+ @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
+ %load = call {float, i1} @llvm.dx.resource.load.rawbuffer(
+ target("dx.RawBuffer", float, 0, 0) %res, i32 0, i32 0)
+ %val = extractvalue { float, i1 } %load, 0
+ ret float %val
+}
+
+attributes #0 = { convergent norecurse nounwind "hlsl.export"}
diff --git a/llvm/test/CodeGen/DirectX/ShaderFlags/typed-uav-load-additional-formats.ll b/llvm/test/CodeGen/DirectX/ShaderFlags/typed-uav-load-additional-formats.ll
index 060d54f961c70..96f80f531fa32 100644
--- a/llvm/test/CodeGen/DirectX/ShaderFlags/typed-uav-load-additional-formats.ll
+++ b/llvm/test/CodeGen/DirectX/ShaderFlags/typed-uav-load-additional-formats.ll
@@ -8,12 +8,13 @@ target triple = "dxil-pc-shadermodel6.7-library"
; CHECK-OBJ: TypedUAVLoadAdditionalFormats: true
; CHECK: Combined Shader Flags for Module
-; CHECK-NEXT: Shader Flags Value: 0x00002000
+; CHECK-NEXT: Shader Flags Value: 0x200002000
; CHECK: Note: shader requires additional functionality:
; CHECK: Typed UAV Load Additional Formats
+; CHECK: Any UAV may not alias any other UAV
-; CHECK: Function multicomponent : 0x00002000
+; CHECK: Function multicomponent : 0x200002000
define <4 x float> @multicomponent() #0 {
%res = call target("dx.TypedBuffer", <4 x float>, 1, 0, 0)
@llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
@@ -23,7 +24,7 @@ define <4 x float> @multicomponent() #0 {
ret <4 x float> %val
}
-; CHECK: Function onecomponent : 0x00000000
+; CHECK: Function onecomponent : 0x200000000
define float @onecomponent() #0 {
%res = call target("dx.TypedBuffer", float, 1, 0, 0)
@llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
@@ -33,7 +34,7 @@ define float @onecomponent() #0 {
ret float %val
}
-; CHECK: Function noload : 0x00000000
+; CHECK: Function noload : 0x200000000
define void @noload(<4 x float> %val) #0 {
%res = call target("dx.TypedBuffer", <4 x float>, 1, 0, 0)
@llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
>From 387906301362337327482d1cac56de8a70b14fd8 Mon Sep 17 00:00:00 2001
From: Icohedron <cheung.deric at gmail.com>
Date: Fri, 14 Mar 2025 00:38:56 +0000
Subject: [PATCH 2/3] Apply clang-format
---
llvm/lib/Target/DirectX/DXILShaderFlags.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/llvm/lib/Target/DirectX/DXILShaderFlags.h b/llvm/lib/Target/DirectX/DXILShaderFlags.h
index 1147296d7173c..b47c79cb293a5 100644
--- a/llvm/lib/Target/DirectX/DXILShaderFlags.h
+++ b/llvm/lib/Target/DirectX/DXILShaderFlags.h
@@ -85,8 +85,8 @@ struct ComputedShaderFlags {
};
struct ModuleShaderFlags {
- void initialize(Module &, DXILResourceTypeMap &DRTM,
- DXILBindingMap &DBM, const ModuleMetadataInfo &MMDI);
+ void initialize(Module &, DXILResourceTypeMap &DRTM, DXILBindingMap &DBM,
+ const ModuleMetadataInfo &MMDI);
const ComputedShaderFlags &getFunctionFlags(const Function *) const;
const ComputedShaderFlags &getCombinedFlags() const { return CombinedSFMask; }
>From ecdb5fa5627ea8f072e08294d1bf3469707af656 Mon Sep 17 00:00:00 2001
From: Icohedron <cheung.deric at gmail.com>
Date: Fri, 14 Mar 2025 18:06:46 +0000
Subject: [PATCH 3/3] Do not set ResMayNotAlias if DXIL Ver <= 1.6
---
llvm/lib/Target/DirectX/DXILShaderFlags.cpp | 17 +++++-----
llvm/lib/Target/DirectX/DXILShaderFlags.h | 5 +--
.../res-may-not-alias-shadermodel6.6.ll | 33 +++++++++++++++++++
3 files changed, 43 insertions(+), 12 deletions(-)
create mode 100644 llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.6.ll
diff --git a/llvm/lib/Target/DirectX/DXILShaderFlags.cpp b/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
index b05ee53798524..1be00ff28a50a 100644
--- a/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
+++ b/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
@@ -120,10 +120,9 @@ void ModuleShaderFlags::updateFunctionFlags(ComputedShaderFlags &CSF,
case Intrinsic::dx_resource_handlefrombinding: {
dxil::ResourceTypeInfo &RTI = DRTM[cast<TargetExtType>(II->getType())];
- // If -res-may-alias is NOT specified, and DXIL Ver > 1.7.
- // Then set ResMayNotAlias if function uses UAVs.
- if (!CSF.ResMayNotAlias && !ResMayAlias &&
- MMDI.DXILVersion > VersionTuple(1, 7) && RTI.isUAV()) {
+ // Set ResMayNotAlias if DXIL version >= 1.8 and function uses UAVs
+ if (!CSF.ResMayNotAlias && CanSetResMayNotAlias &&
+ MMDI.DXILVersion >= VersionTuple(1, 8) && RTI.isUAV()) {
CSF.ResMayNotAlias = true;
}
@@ -165,12 +164,14 @@ void ModuleShaderFlags::initialize(Module &M, DXILResourceTypeMap &DRTM,
DXILBindingMap &DBM,
const ModuleMetadataInfo &MMDI) {
+ CanSetResMayNotAlias = MMDI.DXILVersion >= VersionTuple(1, 7);
+
// Check if -res-may-alias was provided on the command line.
// The command line option will set the dx.resmayalias module flag to 1.
if (auto *RMA = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("dx.resmayalias"))) {
if (RMA->getValue() != 0)
- ResMayAlias = true;
+ CanSetResMayNotAlias = false;
}
CallGraph CG(M);
@@ -197,9 +198,9 @@ void ModuleShaderFlags::initialize(Module &M, DXILResourceTypeMap &DRTM,
continue;
}
- // If -res-may-alias is NOT specified, and DXIL Ver <= 1.7.
- // Then set ResMayNotAlias to true if there are UAVs present globally.
- if (!ResMayAlias && MMDI.DXILVersion <= VersionTuple(1, 7)) {
+ // Set ResMayNotAlias to true if DXIL version < 1.8 and there are UAVs
+ // present globally.
+ if (CanSetResMayNotAlias && MMDI.DXILVersion < VersionTuple(1, 8)) {
SCCSF.ResMayNotAlias = !DBM.uavs().empty();
}
diff --git a/llvm/lib/Target/DirectX/DXILShaderFlags.h b/llvm/lib/Target/DirectX/DXILShaderFlags.h
index b47c79cb293a5..32555587937b0 100644
--- a/llvm/lib/Target/DirectX/DXILShaderFlags.h
+++ b/llvm/lib/Target/DirectX/DXILShaderFlags.h
@@ -91,10 +91,7 @@ struct ModuleShaderFlags {
const ComputedShaderFlags &getCombinedFlags() const { return CombinedSFMask; }
private:
- // A bool to indicate if the -res-may-alias flag was passed to clang-dxc.
- // A module flag "dx.resmayalias" is set to 1 if true.
- // This bool is used in the logic for setting the flag ResMayNotAlias.
- bool ResMayAlias = false;
+ bool CanSetResMayNotAlias;
/// Map of Function-Shader Flag Mask pairs representing properties of each of
/// the functions in the module. Shader Flags of each function represent both
/// module-level and function-level flags
diff --git a/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.6.ll b/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.6.ll
new file mode 100644
index 0000000000000..ec7e25aa7adde
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/ShaderFlags/res-may-not-alias-shadermodel6.6.ll
@@ -0,0 +1,33 @@
+; RUN: opt -S --passes="print-dx-shader-flags" 2>&1 %s | FileCheck %s
+
+target triple = "dxil-pc-shadermodel6.6-library"
+
+; CHECK: Combined Shader Flags for Module
+; CHECK-NEXT: Shader Flags Value: 0x00000010
+
+; CHECK: Note: extra DXIL module flags:
+; CHECK: Raw and Structured buffers
+; CHECK-NOT: Any UAV may not alias any other UAV
+;
+
+; CHECK: Function loadUAV : 0x00000000
+define float @loadUAV() #0 {
+ %res = call target("dx.TypedBuffer", float, 1, 0, 0)
+ @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
+ %load = call {float, i1} @llvm.dx.resource.load.typedbuffer(
+ target("dx.TypedBuffer", float, 1, 0, 0) %res, i32 0)
+ %val = extractvalue {float, i1} %load, 0
+ ret float %val
+}
+
+; CHECK: Function loadSRV : 0x00000010
+define float @loadSRV() #0 {
+ %res = tail call target("dx.RawBuffer", float, 0, 0)
+ @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, i1 false)
+ %load = call {float, i1} @llvm.dx.resource.load.rawbuffer(
+ target("dx.RawBuffer", float, 0, 0) %res, i32 0, i32 0)
+ %val = extractvalue { float, i1 } %load, 0
+ ret float %val
+}
+
+attributes #0 = { convergent norecurse nounwind "hlsl.export"}
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