[HLSL] Use 0 to represent unbounded resources by joaosaffran · Pull Request #186022 · llvm/llvm-project

joaosaffran · 2026-03-12T02:19:34Z

SPIRV backend uses 0 to represent unbounded arrays. This patch makes unbounded resources be represented with 0 when binding them, as well as makes sure the backend uses OpTypeRuntimeArray to represent such cases.
Fix: #183367

llvmbot · 2026-03-12T02:20:09Z

@llvm/pr-subscribers-llvm-analysis
@llvm/pr-subscribers-backend-directx
@llvm/pr-subscribers-hlsl

@llvm/pr-subscribers-clang-codegen

Author: None (joaosaffran)

Changes

SPIRV backend uses 0 to represent unbounded arrays. This patch makes unbounded resources account for this, as well as makes sure the backend uses OpTypeRuntimeArray to represent such cases.

Full diff: https://github.com/llvm/llvm-project/pull/186022.diff

4 Files Affected:

(modified) clang/lib/CodeGen/CGHLSLRuntime.cpp (+6-4)
(modified) clang/test/CodeGenHLSL/resources/res-array-global-unbounded.hlsl (+11-6)
(modified) llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp (+4)
(added) llvm/test/CodeGen/SPIRV/hlsl-resources/unbounded-arr.ll (+34)

diff --git a/clang/lib/CodeGen/CGHLSLRuntime.cpp b/clang/lib/CodeGen/CGHLSLRuntime.cpp
index b695d016c0524..04daa5e611412 100644
--- a/clang/lib/CodeGen/CGHLSLRuntime.cpp
+++ b/clang/lib/CodeGen/CGHLSLRuntime.cpp
@@ -117,11 +117,13 @@ static const ValueDecl *getArrayDecl(const ArraySubscriptExpr *ASE) {
 }
 
 // Get the total size of the array, or -1 if the array is unbounded.
-static int getTotalArraySize(ASTContext &AST, const clang::Type *Ty) {
+static int getTotalArraySize(ASTContext &AST, llvm::Triple::ArchType Arch,
+                             const clang::Type *Ty) {
   Ty = Ty->getUnqualifiedDesugaredType();
   assert(Ty->isArrayType() && "expected array type");
   if (Ty->isIncompleteArrayType())
-    return -1;
+    // Spirv uses 0 to represent unbounded arrays.
+    return Arch == llvm::Triple::ArchType::dxil ? -1 : 0;
   return AST.getConstantArrayElementCount(cast<ConstantArrayType>(Ty));
 }
 
@@ -1280,7 +1282,7 @@ std::optional<LValue> CGHLSLRuntime::emitResourceArraySubscriptExpr(
 
   // Calculate total array size (= range size).
   llvm::Value *Range = llvm::ConstantInt::getSigned(
-      CGM.IntTy, getTotalArraySize(AST, ResArrayTy));
+      CGM.IntTy, getTotalArraySize(AST, getArch(), ResArrayTy));
 
   // If the result of the subscript operation is a single resource, call the
   // constructor.
@@ -1345,7 +1347,7 @@ bool CGHLSLRuntime::emitResourceArrayCopy(LValue &LHS, Expr *RHSExpr,
       AggValueSlot::DoesNotOverlap);
 
   // Create Value for index and total array size (= range size).
-  int Size = getTotalArraySize(AST, ResArrayTy);
+  int Size = getTotalArraySize(AST, getArch(), ResArrayTy);
   llvm::Value *Zero = llvm::ConstantInt::get(CGM.IntTy, 0);
   llvm::Value *Range = llvm::ConstantInt::get(CGM.IntTy, Size);
 
diff --git a/clang/test/CodeGenHLSL/resources/res-array-global-unbounded.hlsl b/clang/test/CodeGenHLSL/resources/res-array-global-unbounded.hlsl
index 6756a26bfc124..7d5b9626db138 100644
--- a/clang/test/CodeGenHLSL/resources/res-array-global-unbounded.hlsl
+++ b/clang/test/CodeGenHLSL/resources/res-array-global-unbounded.hlsl
@@ -30,14 +30,15 @@ void main(uint GI : SV_GroupIndex) {
   // and explicit binding (u10, space1) 
   // CHECK: @hlsl::RWBuffer<float>::__createFromBinding(unsigned int, unsigned int, int, unsigned int, char const*)
   // CHECK-SAME: (ptr {{.*}} sret(%"class.hlsl::RWBuffer.0") align {{(4|8)}} %[[Tmp0]],
-  // CHECK-SAME: i32 noundef 10, i32 noundef 1, i32 noundef -1, i32 noundef 100, ptr noundef @A.str)
+  // DXIL-SAME: i32 noundef 10, i32 noundef 1, i32 noundef -1, i32 noundef 100, ptr noundef @A.str)
+  // SPV-SAME: i32 noundef 10, i32 noundef 1, i32 noundef 0, i32 noundef 100, ptr noundef @A.str)
   // CHECK-NEXT: %[[BufPtr:.*]] = call {{.*}} ptr{{.*}} @hlsl::RWBuffer<float>::operator[](unsigned int)(ptr {{.*}} %[[Tmp0]], i32 noundef 0)
   // CHECK-NEXT: %[[Value1:.*]] = load float, ptr{{.*}} %[[BufPtr]], align 4
   // CHECK-NEXT: store float %[[Value1]], ptr %a, align 4
   float a = A[100][0];
 
   // Make sure B[2][3] is translated to a local RWBuffer<int>[4] array where each array element
-  // is initialized by a constructor call with range -1 and index 52-55 and implicit binding 
+  // is initialized by a constructor call with range 0 and index 52-55 and implicit binding 
   // (space 0, order_id 0) 
   // The first index is calculated from the array dimensions (unbounded x 5 x 4) and indices (2, 3)
   // as 2 * 5 * 4 + 3 * 4 = 52 and the following indices are sequential.
@@ -45,22 +46,26 @@ void main(uint GI : SV_GroupIndex) {
   // CHECK-NEXT: %[[Ptr_Tmp2_0:.*]] = getelementptr [4 x %"class.hlsl::RWBuffer"], ptr %[[Tmp2]], i32 0, i32 0
   // CHECK-NEXT: call void @hlsl::RWBuffer<int>::__createFromImplicitBinding(unsigned int, unsigned int, int, unsigned int, char const*)
   // CHECK-SAME: (ptr {{.*}} sret(%"class.hlsl::RWBuffer") align {{(4|8)}} %[[Ptr_Tmp2_0]], 
-  // CHECK-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 52, ptr noundef @[[BufB]])
+  // DXIL-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 52, ptr noundef @[[BufB]])
+  // SPV-SAME: i32 noundef 0, i32 noundef 0, i32 noundef 0, i32 noundef 52, ptr noundef @[[BufB]])
   
   // CHECK-NEXT: %[[Ptr_Tmp2_1:.*]] = getelementptr [4 x %"class.hlsl::RWBuffer"], ptr %[[Tmp2]], i32 0, i32 1
   // CHECK-NEXT: call void @hlsl::RWBuffer<int>::__createFromImplicitBinding(unsigned int, unsigned int, int, unsigned int, char const*)
   // CHECK-SAME: (ptr {{.*}} sret(%"class.hlsl::RWBuffer") align {{(4|8)}} %[[Ptr_Tmp2_1]], 
-  // CHECK-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 53, ptr noundef @[[BufB]])
+  // DXIL-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 53, ptr noundef @[[BufB]])
+  // SPV-SAME: i32 noundef 0, i32 noundef 0, i32 noundef 0, i32 noundef 53, ptr noundef @[[BufB]])
   
   // CHECK-NEXT: %[[Ptr_Tmp2_2:.*]] = getelementptr [4 x %"class.hlsl::RWBuffer"], ptr %[[Tmp2]], i32 0, i32 2
   // CHECK-NEXT: call void @hlsl::RWBuffer<int>::__createFromImplicitBinding(unsigned int, unsigned int, int, unsigned int, char const*)
   // CHECK-SAME: (ptr {{.*}} sret(%"class.hlsl::RWBuffer") align {{(4|8)}} %[[Ptr_Tmp2_2]], 
-  // CHECK-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 54, ptr noundef @[[BufB]])
+  // DXIL-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 54, ptr noundef @[[BufB]])
+  // SPV-SAME: i32 noundef 0, i32 noundef 0, i32 noundef 0, i32 noundef 54, ptr noundef @[[BufB]])
 
   // CHECK-NEXT: %[[Ptr_Tmp2_3:.*]] = getelementptr [4 x %"class.hlsl::RWBuffer"], ptr %[[Tmp2]], i32 0, i32 3
   // CHECK-NEXT: call void @hlsl::RWBuffer<int>::__createFromImplicitBinding(unsigned int, unsigned int, int, unsigned int, char const*)
   // CHECK-SAME: (ptr {{.*}} sret(%"class.hlsl::RWBuffer") align {{(4|8)}} %[[Ptr_Tmp2_3]], 
-  // CHECK-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 55, ptr noundef @[[BufB]])
+  // DXIL-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 55, ptr noundef @[[BufB]])
+  // SPV-SAME: i32 noundef 0, i32 noundef 0, i32 noundef 0, i32 noundef 55, ptr noundef @[[BufB]])
 
   // DXIL-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 4 %[[Tmp1]], ptr align 4 %[[Tmp2]], i32 16, i1 false)
   // SPV-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 8 %[[Tmp1]], ptr align 8 %[[Tmp2]], i64 32, i1 false)
diff --git a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
index 3e50e4a0e8c80..5e966df6372db 100644
--- a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
@@ -6012,6 +6012,10 @@ bool SPIRVInstructionSelector::loadHandleBeforePosition(
     SC = GR.getPointerStorageClass(ResType);
   }
 
+  if (ResType->getOpcode() == SPIRV::OpTypeImage && ArraySize == 0)
+    MIRBuilder.buildInstr(SPIRV::OpCapability)
+        .addImm(SPIRV::Capability::RuntimeDescriptorArrayEXT);
+
   Register VarReg =
       buildPointerToResource(SPIRVTypeInst(VarType), SC, Set, Binding,
                              ArraySize, IndexReg, Name, MIRBuilder);
diff --git a/llvm/test/CodeGen/SPIRV/hlsl-resources/unbounded-arr.ll b/llvm/test/CodeGen/SPIRV/hlsl-resources/unbounded-arr.ll
new file mode 100644
index 0000000000000..8be0da57a797b
--- /dev/null
+++ b/llvm/test/CodeGen/SPIRV/hlsl-resources/unbounded-arr.ll
@@ -0,0 +1,34 @@
+; RUN: llc -O0 -verify-machineinstrs -mtriple=spirv1.6-vulkan1.3-library %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv1.6-vulkan1.3-library %s -o - -filetype=obj | spirv-val %}
+
+; CHECK-DAG: OpCapability RuntimeDescriptorArrayEXT
+; CHECK-DAG: %[[int32:[0-9]+]] = OpTypeInt 32 0
+; CHECK-DAG: %[[rwbuffer:[0-9]+]] = OpTypeImage %[[int32]] Buffer 2 0 0 2 R32i
+; CHECK-DAG: OpTypeRuntimeArray %[[rwbuffer]]
+
+; This IR was emmited from the following HLSL code:
+; [[vk::binding(0)]]
+; RWBuffer<int> Buf[] : register(u0);
+; 
+; [numthreads(4,2,1)]
+; void main(uint GI : SV_GroupIndex) {
+;     Buf[0][0] = 0;
+; }
+
+
+
+@Buf.str = private unnamed_addr constant [4 x i8] c"Buf\00", align 1
+
+; Function Attrs: convergent noinline norecurse
+define void @main() #0 {
+entry:
+  %2 = call target("spirv.SignedImage", i32, 5, 2, 0, 0, 2, 24) @llvm.spv.resource.handlefrombinding.tspirv.SignedImage_i32_5_2_0_0_2_24t(i32 0, i32 0, i32 0, i32 0, ptr @Buf.str)
+  %3 = call noundef align 4 dereferenceable(4) ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.SignedImage_i32_5_2_0_0_2_24t(target("spirv.SignedImage", i32, 5, 2, 0, 0, 2, 24)  %2, i32 0)
+  store i32 0, ptr addrspace(11) %3, align 4
+  ret void
+}
+; Function Attrs: nocallback nofree nosync nounwind willreturn memory(none)
+declare target("spirv.SignedImage", i32, 5, 2, 0, 0, 2, 24) @llvm.spv.resource.handlefrombinding.tspirv.SignedImage_i32_5_2_0_0_2_24t(i32, i32, i32, i32, ptr) #3
+
+attributes #0 = { convergent noinline norecurse "hlsl.numthreads"="4,2,1" "hlsl.shader"="compute" "no-nans-fp-math"="true" "no-signed-zeros-fp-math"="true" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
+attributes #3 = { nocallback nofree nosync nounwind willreturn memory(none) }

llvmbot · 2026-03-12T02:20:10Z

@llvm/pr-subscribers-backend-spir-v

Author: None (joaosaffran)

Changes

SPIRV backend uses 0 to represent unbounded arrays. This patch makes unbounded resources account for this, as well as makes sure the backend uses OpTypeRuntimeArray to represent such cases.

Full diff: https://github.com/llvm/llvm-project/pull/186022.diff

4 Files Affected:

(modified) clang/lib/CodeGen/CGHLSLRuntime.cpp (+6-4)
(modified) clang/test/CodeGenHLSL/resources/res-array-global-unbounded.hlsl (+11-6)
(modified) llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp (+4)
(added) llvm/test/CodeGen/SPIRV/hlsl-resources/unbounded-arr.ll (+34)

diff --git a/clang/lib/CodeGen/CGHLSLRuntime.cpp b/clang/lib/CodeGen/CGHLSLRuntime.cpp
index b695d016c0524..04daa5e611412 100644
--- a/clang/lib/CodeGen/CGHLSLRuntime.cpp
+++ b/clang/lib/CodeGen/CGHLSLRuntime.cpp
@@ -117,11 +117,13 @@ static const ValueDecl *getArrayDecl(const ArraySubscriptExpr *ASE) {
 }
 
 // Get the total size of the array, or -1 if the array is unbounded.
-static int getTotalArraySize(ASTContext &AST, const clang::Type *Ty) {
+static int getTotalArraySize(ASTContext &AST, llvm::Triple::ArchType Arch,
+                             const clang::Type *Ty) {
   Ty = Ty->getUnqualifiedDesugaredType();
   assert(Ty->isArrayType() && "expected array type");
   if (Ty->isIncompleteArrayType())
-    return -1;
+    // Spirv uses 0 to represent unbounded arrays.
+    return Arch == llvm::Triple::ArchType::dxil ? -1 : 0;
   return AST.getConstantArrayElementCount(cast<ConstantArrayType>(Ty));
 }
 
@@ -1280,7 +1282,7 @@ std::optional<LValue> CGHLSLRuntime::emitResourceArraySubscriptExpr(
 
   // Calculate total array size (= range size).
   llvm::Value *Range = llvm::ConstantInt::getSigned(
-      CGM.IntTy, getTotalArraySize(AST, ResArrayTy));
+      CGM.IntTy, getTotalArraySize(AST, getArch(), ResArrayTy));
 
   // If the result of the subscript operation is a single resource, call the
   // constructor.
@@ -1345,7 +1347,7 @@ bool CGHLSLRuntime::emitResourceArrayCopy(LValue &LHS, Expr *RHSExpr,
       AggValueSlot::DoesNotOverlap);
 
   // Create Value for index and total array size (= range size).
-  int Size = getTotalArraySize(AST, ResArrayTy);
+  int Size = getTotalArraySize(AST, getArch(), ResArrayTy);
   llvm::Value *Zero = llvm::ConstantInt::get(CGM.IntTy, 0);
   llvm::Value *Range = llvm::ConstantInt::get(CGM.IntTy, Size);
 
diff --git a/clang/test/CodeGenHLSL/resources/res-array-global-unbounded.hlsl b/clang/test/CodeGenHLSL/resources/res-array-global-unbounded.hlsl
index 6756a26bfc124..7d5b9626db138 100644
--- a/clang/test/CodeGenHLSL/resources/res-array-global-unbounded.hlsl
+++ b/clang/test/CodeGenHLSL/resources/res-array-global-unbounded.hlsl
@@ -30,14 +30,15 @@ void main(uint GI : SV_GroupIndex) {
   // and explicit binding (u10, space1) 
   // CHECK: @hlsl::RWBuffer<float>::__createFromBinding(unsigned int, unsigned int, int, unsigned int, char const*)
   // CHECK-SAME: (ptr {{.*}} sret(%"class.hlsl::RWBuffer.0") align {{(4|8)}} %[[Tmp0]],
-  // CHECK-SAME: i32 noundef 10, i32 noundef 1, i32 noundef -1, i32 noundef 100, ptr noundef @A.str)
+  // DXIL-SAME: i32 noundef 10, i32 noundef 1, i32 noundef -1, i32 noundef 100, ptr noundef @A.str)
+  // SPV-SAME: i32 noundef 10, i32 noundef 1, i32 noundef 0, i32 noundef 100, ptr noundef @A.str)
   // CHECK-NEXT: %[[BufPtr:.*]] = call {{.*}} ptr{{.*}} @hlsl::RWBuffer<float>::operator[](unsigned int)(ptr {{.*}} %[[Tmp0]], i32 noundef 0)
   // CHECK-NEXT: %[[Value1:.*]] = load float, ptr{{.*}} %[[BufPtr]], align 4
   // CHECK-NEXT: store float %[[Value1]], ptr %a, align 4
   float a = A[100][0];
 
   // Make sure B[2][3] is translated to a local RWBuffer<int>[4] array where each array element
-  // is initialized by a constructor call with range -1 and index 52-55 and implicit binding 
+  // is initialized by a constructor call with range 0 and index 52-55 and implicit binding 
   // (space 0, order_id 0) 
   // The first index is calculated from the array dimensions (unbounded x 5 x 4) and indices (2, 3)
   // as 2 * 5 * 4 + 3 * 4 = 52 and the following indices are sequential.
@@ -45,22 +46,26 @@ void main(uint GI : SV_GroupIndex) {
   // CHECK-NEXT: %[[Ptr_Tmp2_0:.*]] = getelementptr [4 x %"class.hlsl::RWBuffer"], ptr %[[Tmp2]], i32 0, i32 0
   // CHECK-NEXT: call void @hlsl::RWBuffer<int>::__createFromImplicitBinding(unsigned int, unsigned int, int, unsigned int, char const*)
   // CHECK-SAME: (ptr {{.*}} sret(%"class.hlsl::RWBuffer") align {{(4|8)}} %[[Ptr_Tmp2_0]], 
-  // CHECK-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 52, ptr noundef @[[BufB]])
+  // DXIL-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 52, ptr noundef @[[BufB]])
+  // SPV-SAME: i32 noundef 0, i32 noundef 0, i32 noundef 0, i32 noundef 52, ptr noundef @[[BufB]])
   
   // CHECK-NEXT: %[[Ptr_Tmp2_1:.*]] = getelementptr [4 x %"class.hlsl::RWBuffer"], ptr %[[Tmp2]], i32 0, i32 1
   // CHECK-NEXT: call void @hlsl::RWBuffer<int>::__createFromImplicitBinding(unsigned int, unsigned int, int, unsigned int, char const*)
   // CHECK-SAME: (ptr {{.*}} sret(%"class.hlsl::RWBuffer") align {{(4|8)}} %[[Ptr_Tmp2_1]], 
-  // CHECK-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 53, ptr noundef @[[BufB]])
+  // DXIL-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 53, ptr noundef @[[BufB]])
+  // SPV-SAME: i32 noundef 0, i32 noundef 0, i32 noundef 0, i32 noundef 53, ptr noundef @[[BufB]])
   
   // CHECK-NEXT: %[[Ptr_Tmp2_2:.*]] = getelementptr [4 x %"class.hlsl::RWBuffer"], ptr %[[Tmp2]], i32 0, i32 2
   // CHECK-NEXT: call void @hlsl::RWBuffer<int>::__createFromImplicitBinding(unsigned int, unsigned int, int, unsigned int, char const*)
   // CHECK-SAME: (ptr {{.*}} sret(%"class.hlsl::RWBuffer") align {{(4|8)}} %[[Ptr_Tmp2_2]], 
-  // CHECK-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 54, ptr noundef @[[BufB]])
+  // DXIL-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 54, ptr noundef @[[BufB]])
+  // SPV-SAME: i32 noundef 0, i32 noundef 0, i32 noundef 0, i32 noundef 54, ptr noundef @[[BufB]])
 
   // CHECK-NEXT: %[[Ptr_Tmp2_3:.*]] = getelementptr [4 x %"class.hlsl::RWBuffer"], ptr %[[Tmp2]], i32 0, i32 3
   // CHECK-NEXT: call void @hlsl::RWBuffer<int>::__createFromImplicitBinding(unsigned int, unsigned int, int, unsigned int, char const*)
   // CHECK-SAME: (ptr {{.*}} sret(%"class.hlsl::RWBuffer") align {{(4|8)}} %[[Ptr_Tmp2_3]], 
-  // CHECK-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 55, ptr noundef @[[BufB]])
+  // DXIL-SAME: i32 noundef 0, i32 noundef 0, i32 noundef -1, i32 noundef 55, ptr noundef @[[BufB]])
+  // SPV-SAME: i32 noundef 0, i32 noundef 0, i32 noundef 0, i32 noundef 55, ptr noundef @[[BufB]])
 
   // DXIL-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 4 %[[Tmp1]], ptr align 4 %[[Tmp2]], i32 16, i1 false)
   // SPV-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 8 %[[Tmp1]], ptr align 8 %[[Tmp2]], i64 32, i1 false)
diff --git a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
index 3e50e4a0e8c80..5e966df6372db 100644
--- a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
@@ -6012,6 +6012,10 @@ bool SPIRVInstructionSelector::loadHandleBeforePosition(
     SC = GR.getPointerStorageClass(ResType);
   }
 
+  if (ResType->getOpcode() == SPIRV::OpTypeImage && ArraySize == 0)
+    MIRBuilder.buildInstr(SPIRV::OpCapability)
+        .addImm(SPIRV::Capability::RuntimeDescriptorArrayEXT);
+
   Register VarReg =
       buildPointerToResource(SPIRVTypeInst(VarType), SC, Set, Binding,
                              ArraySize, IndexReg, Name, MIRBuilder);
diff --git a/llvm/test/CodeGen/SPIRV/hlsl-resources/unbounded-arr.ll b/llvm/test/CodeGen/SPIRV/hlsl-resources/unbounded-arr.ll
new file mode 100644
index 0000000000000..8be0da57a797b
--- /dev/null
+++ b/llvm/test/CodeGen/SPIRV/hlsl-resources/unbounded-arr.ll
@@ -0,0 +1,34 @@
+; RUN: llc -O0 -verify-machineinstrs -mtriple=spirv1.6-vulkan1.3-library %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv1.6-vulkan1.3-library %s -o - -filetype=obj | spirv-val %}
+
+; CHECK-DAG: OpCapability RuntimeDescriptorArrayEXT
+; CHECK-DAG: %[[int32:[0-9]+]] = OpTypeInt 32 0
+; CHECK-DAG: %[[rwbuffer:[0-9]+]] = OpTypeImage %[[int32]] Buffer 2 0 0 2 R32i
+; CHECK-DAG: OpTypeRuntimeArray %[[rwbuffer]]
+
+; This IR was emmited from the following HLSL code:
+; [[vk::binding(0)]]
+; RWBuffer<int> Buf[] : register(u0);
+; 
+; [numthreads(4,2,1)]
+; void main(uint GI : SV_GroupIndex) {
+;     Buf[0][0] = 0;
+; }
+
+
+
+@Buf.str = private unnamed_addr constant [4 x i8] c"Buf\00", align 1
+
+; Function Attrs: convergent noinline norecurse
+define void @main() #0 {
+entry:
+  %2 = call target("spirv.SignedImage", i32, 5, 2, 0, 0, 2, 24) @llvm.spv.resource.handlefrombinding.tspirv.SignedImage_i32_5_2_0_0_2_24t(i32 0, i32 0, i32 0, i32 0, ptr @Buf.str)
+  %3 = call noundef align 4 dereferenceable(4) ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.SignedImage_i32_5_2_0_0_2_24t(target("spirv.SignedImage", i32, 5, 2, 0, 0, 2, 24)  %2, i32 0)
+  store i32 0, ptr addrspace(11) %3, align 4
+  ret void
+}
+; Function Attrs: nocallback nofree nosync nounwind willreturn memory(none)
+declare target("spirv.SignedImage", i32, 5, 2, 0, 0, 2, 24) @llvm.spv.resource.handlefrombinding.tspirv.SignedImage_i32_5_2_0_0_2_24t(i32, i32, i32, i32, ptr) #3
+
+attributes #0 = { convergent noinline norecurse "hlsl.numthreads"="4,2,1" "hlsl.shader"="compute" "no-nans-fp-math"="true" "no-signed-zeros-fp-math"="true" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
+attributes #3 = { nocallback nofree nosync nounwind willreturn memory(none) }

bogner

This is not how we should do this - having the value we use to represent unbounded depend on the target is a recipe for user error and confusion. If we're changing to use 0 for unbounded instead of -1, we need to do this for all targets and update whatever documentation we have (ie, change the definition of the intrinsic such that the value 0 means unbounded). Otherwise, if we need this to stay as -1 for DirectX for some good reason, then we should instead take @s-perron's suggestion in #185551 (comment) and handle converting this to a zero in the SPIR-V backend early (when we're handling the intrinsic itself).

github-actions · 2026-03-12T18:47:47Z

🐧 Linux x64 Test Results

199341 tests passed
6211 tests skipped

✅ The build succeeded and all tests passed.

github-actions · 2026-03-12T20:04:15Z

✅ With the latest revision this PR passed the C/C++ code formatter.

bogner · 2026-03-12T20:44:37Z

Need to update this comment

bogner · 2026-03-12T21:41:15Z

-                           Size,           HandleTy, Name};
+          ResourceInfo RI = ResourceInfo{
+              /*RecordID=*/0,         Space,    LowerBound,
+              Size == 0 ? ~0U : Size, HandleTy, Name};


I feel like converting to ~0U here makes this harder to follow. At some points in the backend, 0 means unbounded, but at other points, it's ~0U.

It would be better to consistently use 0 throughout. The main places where we need to do something different are where we convert to an UpperBound (which already has special logic everywhere it happens), a few places where we print specially, and when we emit this into the metadata (we'll need to convert from 0 to ~0U to match the DXIL semantics there).

bogner · 2026-03-12T22:10:06Z

+; Function Attrs: nocallback nofree nosync nounwind willreturn memory(none)
+declare target("spirv.SignedImage", i32, 5, 2, 0, 0, 2, 24) @llvm.spv.resource.handlefrombinding.tspirv.SignedImage_i32_5_2_0_0_2_24t(i32, i32, i32, i32, ptr) #3


Can simplify by removing the declaration here and letting the parser find it.

bogner · 2026-03-12T22:11:26Z

+  %2 = call target("spirv.SignedImage", i32, 5, 2, 0, 0, 2, 24) @llvm.spv.resource.handlefrombinding.tspirv.SignedImage_i32_5_2_0_0_2_24t(i32 0, i32 0, i32 0, i32 0, ptr @Buf.str)
+  %3 = call noundef align 4 dereferenceable(4) ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.SignedImage_i32_5_2_0_0_2_24t(target("spirv.SignedImage", i32, 5, 2, 0, 0, 2, 24)  %2, i32 0)


This IR is technically invalid, since the numbered values aren't contiguous and starting from 0. Better to name these values instead of using numbers in any case.

We could also simplify this slightly by just saying @llvm.spv.resource.handlefrombinding( and @llvm.spv.resource.getpointer( instead of spelling out the overloads.

bob80905

LGTM

llvm-ci · 2026-03-16T21:00:18Z

LLVM Buildbot has detected a new failure on builder openmp-s390x-linux running on systemz-1 while building clang,llvm at step 6 "test-openmp".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/88/builds/21500

Here is the relevant piece of the build log for the reference

Step 6 (test-openmp) failure: test (failure)
******************** TEST 'libomp :: tasking/issue-94260-2.c' FAILED ********************
Exit Code: -11

Command Output (stdout):
--
# RUN: at line 1
/home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/./bin/clang -fopenmp   -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test -L /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src  -fno-omit-frame-pointer -mbackchain -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/ompt /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/tasking/issue-94260-2.c -o /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/tasking/Output/issue-94260-2.c.tmp -lm -latomic && /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/tasking/Output/issue-94260-2.c.tmp
# executed command: /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/./bin/clang -fopenmp -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test -L /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -fno-omit-frame-pointer -mbackchain -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/ompt /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/tasking/issue-94260-2.c -o /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/tasking/Output/issue-94260-2.c.tmp -lm -latomic
# executed command: /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/tasking/Output/issue-94260-2.c.tmp
# note: command had no output on stdout or stderr
# error: command failed with exit status: -11

--

********************

…87174) this patch updates the shader flags to account for 0 being used to represent unbounded arrays. This was a missed updated from the previous pr #186022. This change is required to make sure the following offload test pass dxv validation: ``` OffloadTest-clang-d3d12 :: Feature/ResourceArrays/multi-dim-unbounded-array-nuri.test OffloadTest-clang-d3d12 :: Feature/ResourceArrays/multi-dim-unbounded-array.test OffloadTest-clang-d3d12 :: Feature/ResourceArrays/unbounded-array-nuri.test OffloadTest-clang-d3d12 :: Feature/ResourceArrays/unbounded-array.test ``` --------- Co-authored-by: Joao Saffran <jderezende@microsoft.com>

joaosaffran added 3 commits March 11, 2026 14:21

replace -1 with 0 when targeting spirv

d006275

add missing capability emission

201e771

check if the capabily is being emited

ba10d09

llvmbot added clang:codegen IR generation bugs: mangling, exceptions, etc. HLSL HLSL Language Support backend:SPIR-V labels Mar 12, 2026

joaosaffran requested review from bogner, hekota and s-perron March 12, 2026 02:21

bogner requested changes Mar 12, 2026

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llvmbot added backend:DirectX llvm:analysis Includes value tracking, cost tables and constant folding labels Mar 12, 2026

joaosaffran marked this pull request as draft March 12, 2026 17:55

use 0 instead of -1

1bc576f

joaosaffran force-pushed the bugfix/hlsl/use-0-unbounded branch from ab3bf95 to 1bc576f Compare March 12, 2026 20:02

joaosaffran requested a review from bogner March 12, 2026 20:03

format

1d7543a

joaosaffran changed the title ~~[HLSL][SPIRV] Use 0 to represent unbounded resources when targeting SPIRV~~ [HLSL] Use 0 to represent unbounded resources Mar 12, 2026

joaosaffran marked this pull request as ready for review March 12, 2026 20:33

bogner reviewed Mar 12, 2026

View reviewed changes

joaosaffran marked this pull request as draft March 13, 2026 02:08

joaosaffran added 5 commits March 12, 2026 19:47

save ongoing work

d055cc6

fix typo

962c03b

fix preatty print

ebba1bf

fix issue

b5b7338

pass another test

47b165d

joaosaffran added 4 commits March 16, 2026 10:34

format

9ff6618

fix metadata and simplify < operator

4cecb04

fix comment

c666c55

simplify test and correct comment

de4ee46

joaosaffran marked this pull request as ready for review March 16, 2026 19:10

joaosaffran requested a review from bogner March 16, 2026 19:10

bogner approved these changes Mar 16, 2026

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bob80905 approved these changes Mar 16, 2026

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joaosaffran merged commit a12b612 into llvm:main Mar 16, 2026
14 of 15 checks passed

bob80905 mentioned this pull request Mar 16, 2026

[HLSL] Add globals for resources embedded in structs #184281

Merged

hekota added a commit to hekota/llvm-project that referenced this pull request Mar 17, 2026

Update unbounded array size to 0 since llvm#186022 has merged

3bd1b4c

joaosaffran mentioned this pull request Mar 18, 2026

[HLSL][SPIRV] Use 0 to represent unbounded arrays on shader flags #187174

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[HLSL] Use 0 to represent unbounded resources#186022

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		; Function Attrs: nocallback nofree nosync nounwind willreturn memory(none)
		declare target("spirv.SignedImage", i32, 5, 2, 0, 0, 2, 24) @llvm.spv.resource.handlefrombinding.tspirv.SignedImage_i32_5_2_0_0_2_24t(i32, i32, i32, i32, ptr) #3

		%2 = call target("spirv.SignedImage", i32, 5, 2, 0, 0, 2, 24) @llvm.spv.resource.handlefrombinding.tspirv.SignedImage_i32_5_2_0_0_2_24t(i32 0, i32 0, i32 0, i32 0, ptr @Buf.str)
		%3 = call noundef align 4 dereferenceable(4) ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.SignedImage_i32_5_2_0_0_2_24t(target("spirv.SignedImage", i32, 5, 2, 0, 0, 2, 24) %2, i32 0)

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