[HLSL] Codegen for indexing of sub-arrays of multi-dimensional resource arrays

Closes #145426

clang/lib/CodeGen/CGHLSLRuntime.cpp

@@ -18,6 +18,7 @@
 #include "CodeGenModule.h"
 #include "TargetInfo.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/Attrs.inc"
 #include "clang/AST/Decl.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/AST/Type.h"
@@ -36,6 +37,7 @@
 #include "llvm/Support/Alignment.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FormatVariadic.h"
+#include <cstdint>
 
 using namespace clang;
 using namespace CodeGen;
@@ -190,6 +192,71 @@ static void createResourceCtorArgs(CodeGenModule &CGM, CXXConstructorDecl *CD,
   Args.add(RValue::get(NameStr), AST.getPointerType(AST.CharTy.withConst()));
 }
 
+// Initializes local resource array variable. For multi-dimensional arrays it
+// calls itself recursively to initialize its sub-arrays. The Index used in the
+// resource constructor calls will begin at StartIndex and will be incremented
+// for each array element. The last last used resource Index is returned to the
+// caller.
+static Value *initializeLocalResourceArray(
+    CodeGenFunction &CGF, AggValueSlot &ValueSlot,
+    const ConstantArrayType *ArrayTy, CXXConstructorDecl *CD,
+    llvm::Value *Range, llvm::Value *StartIndex, StringRef ResourceName,
+    HLSLResourceBindingAttr *RBA, HLSLVkBindingAttr *VkBinding,
+    ArrayRef<llvm::Value *> PrevGEPIndices, SourceLocation ArraySubsExprLoc) {
+
+  llvm::IntegerType *IntTy = CGF.CGM.IntTy;
+  llvm::Value *Index = StartIndex;
+  llvm::Value *One = llvm::ConstantInt::get(IntTy, 1);
+  uint64_t ArraySize = ArrayTy->getSExtSize();
+  QualType ElemType = ArrayTy->getElementType();
+  Address TmpArrayAddr = ValueSlot.getAddress();
+
+  // Add additional index to the getelementptr call indices.
+  // This index will be updated for each array element in the loops below.
+  SmallVector<llvm::Value *> GEPIndices(PrevGEPIndices);
+  GEPIndices.push_back(llvm::ConstantInt::get(IntTy, 0));
+
+  // array of arrays - recursively initialize the sub-arrays
+  if (ElemType->isArrayType()) {
+    const ConstantArrayType *SubArrayTy = cast<ConstantArrayType>(ElemType);
+    for (uint64_t I = 0; I < ArraySize; I++) {
+      if (I > 0) {
+        Index = CGF.Builder.CreateAdd(Index, One);
+        GEPIndices.back() = llvm::ConstantInt::get(IntTy, I);
+      }
+      // recursively initialize the sub-array
+      Index = initializeLocalResourceArray(
+          CGF, ValueSlot, SubArrayTy, CD, Range, Index, ResourceName, RBA,
+          VkBinding, GEPIndices, ArraySubsExprLoc);
+    }
+    return Index;
+  }
+
+  // array of resources - initialize each resource in the array
+  llvm::Type *Ty = CGF.ConvertTypeForMem(ElemType);
+  CharUnits ElemSize = CD->getASTContext().getTypeSizeInChars(ElemType);
+  CharUnits Align =
+      TmpArrayAddr.getAlignment().alignmentOfArrayElement(ElemSize);
+
+  for (uint64_t I = 0; I < ArraySize; I++) {
+    if (I > 0) {
+      Index = CGF.Builder.CreateAdd(Index, One);
+      GEPIndices.back() = llvm::ConstantInt::get(IntTy, I);
+    }
+    Address ThisAddress =
+        CGF.Builder.CreateGEP(TmpArrayAddr, GEPIndices, Ty, Align);
+    llvm::Value *ThisPtr = CGF.getAsNaturalPointerTo(ThisAddress, ElemType);
+
+    CallArgList Args;
+    createResourceCtorArgs(CGF.CGM, CD, ThisPtr, Range, Index, ResourceName,
+                           RBA, VkBinding, Args);
+    CGF.EmitCXXConstructorCall(CD, Ctor_Complete, false, false, ThisAddress,
+                               Args, ValueSlot.mayOverlap(), ArraySubsExprLoc,
+                               ValueSlot.isSanitizerChecked());
+  }
+  return Index;
+}
+
 } // namespace
 
 llvm::Type *
@@ -802,16 +869,14 @@ std::optional<LValue> CGHLSLRuntime::emitResourceArraySubscriptExpr(
          ArraySubsExpr->getType()->isHLSLResourceRecordArray() &&
              "expected resource array subscript expression");
 
-  // let clang codegen handle local resource array subscripts
-  const VarDecl *ArrayDecl = dyn_cast<VarDecl>(getArrayDecl(ArraySubsExpr));
+  // Let clang codegen handle local resource array subscripts,
+  // or when the subscript references on opaque expression (as part of
+  // ArrayInitLoopExpr AST node).
+  const VarDecl *ArrayDecl =
+      dyn_cast_or_null<VarDecl>(getArrayDecl(ArraySubsExpr));
   if (!ArrayDecl || !ArrayDecl->hasGlobalStorage())
     return std::nullopt;
 
-  if (ArraySubsExpr->getType()->isArrayType())
-    // FIXME: this is not yet implemented (llvm/llvm-project#145426)
-    llvm_unreachable(
-        "indexing of sub-arrays of multidimensional arrays not supported yet");
-
   // get the resource array type
   ASTContext &AST = ArrayDecl->getASTContext();
   const Type *ResArrayTy = ArrayDecl->getType().getTypePtr();
@@ -832,26 +897,30 @@ std::optional<LValue> CGHLSLRuntime::emitResourceArraySubscriptExpr(
           CGM.IntTy, AST.getConstantArrayElementCount(ArrayTy));
       SubIndex = CGF.Builder.CreateMul(SubIndex, Multiplier);
     }
-
     Index = Index ? CGF.Builder.CreateAdd(Index, SubIndex) : SubIndex;
     ASE = dyn_cast<ArraySubscriptExpr>(ASE->getBase()->IgnoreParenImpCasts());
   }
 
   // find binding info for the resource array (for implicit binding
   // an HLSLResourceBindingAttr should have been added by SemaHLSL)
-  QualType ResourceTy = ArraySubsExpr->getType();
   HLSLVkBindingAttr *VkBinding = ArrayDecl->getAttr<HLSLVkBindingAttr>();
   HLSLResourceBindingAttr *RBA = ArrayDecl->getAttr<HLSLResourceBindingAttr>();
   assert((VkBinding || RBA) && "resource array must have a binding attribute");
 
+  // Find the individual resource type
+  QualType ResultTy = ArraySubsExpr->getType();
+  QualType ResourceTy =
+      ResultTy->isArrayType() ? AST.getBaseElementType(ResultTy) : ResultTy;
+
   // lookup the resource class constructor based on the resource type and
   // binding
   CXXConstructorDecl *CD = findResourceConstructorDecl(
       AST, ResourceTy, VkBinding || RBA->hasRegisterSlot());
 
-  // create a temporary variable for the resource class instance (we need to
+  // create a temporary variable for the result, which is either going
+  // to be a single resource instance or a local array of resources (we need to
   // return an LValue)
-  RawAddress TmpVar = CGF.CreateMemTemp(ResourceTy);
+  RawAddress TmpVar = CGF.CreateMemTemp(ResultTy);
   if (CGF.EmitLifetimeStart(TmpVar.getPointer()))
     CGF.pushFullExprCleanup<CodeGenFunction::CallLifetimeEnd>(
         NormalEHLifetimeMarker, TmpVar);
@@ -860,26 +929,35 @@ std::optional<LValue> CGHLSLRuntime::emitResourceArraySubscriptExpr(
       TmpVar, Qualifiers(), AggValueSlot::IsDestructed_t(true),
       AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsAliased_t(false),
       AggValueSlot::DoesNotOverlap);
-
-  Address ThisAddress = ValueSlot.getAddress();
-  llvm::Value *ThisPtr = CGF.getAsNaturalPointerTo(
-      ThisAddress, CD->getThisType()->getPointeeType());
+  Address TmpVarAddress = ValueSlot.getAddress();
 
   // get total array size (= range size)
   llvm::Value *Range =
       llvm::ConstantInt::get(CGM.IntTy, getTotalArraySize(AST, ResArrayTy));
 
-  // assemble the constructor parameters
-  CallArgList Args;
-  createResourceCtorArgs(CGM, CD, ThisPtr, Range, Index, ArrayDecl->getName(),
-                         RBA, VkBinding, Args);
+  // if the result of the subscript operation is a single resource - call the
+  // constructor
+  if (ResultTy == ResourceTy) {
+    QualType ThisType = CD->getThisType()->getPointeeType();
+    llvm::Value *ThisPtr = CGF.getAsNaturalPointerTo(TmpVarAddress, ThisType);
 
-  // call the constructor
-  CGF.EmitCXXConstructorCall(CD, Ctor_Complete, false, false, ThisAddress, Args,
-                             ValueSlot.mayOverlap(),
-                             ArraySubsExpr->getExprLoc(),
-                             ValueSlot.isSanitizerChecked());
-
-  return CGF.MakeAddrLValue(TmpVar, ArraySubsExpr->getType(),
-                            AlignmentSource::Decl);
+    // assemble the constructor parameters
+    CallArgList Args;
+    createResourceCtorArgs(CGM, CD, ThisPtr, Range, Index, ArrayDecl->getName(),
+                           RBA, VkBinding, Args);
+    // call the constructor
+    CGF.EmitCXXConstructorCall(CD, Ctor_Complete, false, false, TmpVarAddress,
+                               Args, ValueSlot.mayOverlap(),
+                               ArraySubsExpr->getExprLoc(),
+                               ValueSlot.isSanitizerChecked());
+  } else {
+    // result of the subscript operation is a local resource array
+    const ConstantArrayType *ArrayTy =
+        cast<ConstantArrayType>(ResultTy.getTypePtr());
+    initializeLocalResourceArray(CGF, ValueSlot, ArrayTy, CD, Range, Index,
+                                 ArrayDecl->getName(), RBA, VkBinding,
+                                 {llvm::ConstantInt::get(CGM.IntTy, 0)},
+                                 ArraySubsExpr->getExprLoc());
+  }
+  return CGF.MakeAddrLValue(TmpVar, ResultTy, AlignmentSource::Decl);
 }

clang/test/CodeGenHLSL/resources/res-array-global-subarray-many.hlsl

@@ -0,0 +1,102 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.6-compute -finclude-default-header \
+// RUN:   -emit-llvm -disable-llvm-passes -o - %s | FileCheck %s
+
+// CHECK: @[[BufA:.*]] = private unnamed_addr constant [2 x i8] c"A\00", align 1
+
+RWBuffer<float> A[5][4][3][2] : register(u10, space2);
+RWStructuredBuffer<float> Out;
+
+float foo(RWBuffer<float> Arr[3][2]) {
+  return Arr[1][0][0];
+}
+
+// NOTE:
+// - _ZN4hlsl8RWBufferIfEC1EjjijPKc is the constructor call for explicit binding
+//    (has "jjij" in the mangled name) and the arguments are (register, space, range_size, index, name).
+// - _ZN4hlsl8RWBufferIfEixEj is the subscript operator for RWBuffer<float>
+
+// CHECK: define internal void @_Z4mainj(i32 noundef %GI)
+// CHECK-NEXT: entry:
+// CHECK-NEXT: %[[GI_alloca:.*]] = alloca i32, align 4
+// CHECK-NEXT: %Sub = alloca [3 x [2 x %"class.hlsl::RWBuffer"]], align 4
+// CHECK-NEXT: %[[Tmp0:.*]] = alloca [3 x [2 x %"class.hlsl::RWBuffer"]], align 4
+// CHECK-NEXT: %a = alloca float, align 4
+// CHECK-NEXT: %b = alloca float, align 4
+// CHECK-NEXT: %[[Tmp1:.*]] = alloca [3 x [2 x %"class.hlsl::RWBuffer"]], align 4
+// CHECK-NEXT: %[[Tmp2:.*]] = alloca [3 x [2 x %"class.hlsl::RWBuffer"]], align 4
+// CHECK-NEXT: store i32 %GI, ptr %[[GI_alloca]], align 4
+[numthreads(4,1,1)]
+void main(uint GI : SV_GroupThreadID) {
+// Codegen for "A[4][1]" - create local array [[Tmp0]] of size 3 x 2 and initialize
+// each element by a call to the resource constructor
+// The resource index for A[4][1][0][0] is 102 = 4 * (4 * 3 * 2) + 1 * (3 * 2)
+// (index in the resource array as if it was flattened)
+// CHECK-NEXT: %[[Ptr_Tmp0_0_0:.*]] = getelementptr [3 x [2 x %"class.hlsl::RWBuffer"]], ptr %tmp, i32 0, i32 0, i32 0
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp0_0_0]], i32 noundef 10, i32 noundef 2, i32 noundef 120, i32 noundef 102, ptr noundef @A.str) #6
+// CHECK-NEXT: %[[Ptr_Tmp0_0_1:.*]] = getelementptr [3 x [2 x %"class.hlsl::RWBuffer"]], ptr %tmp, i32 0, i32 0, i32 1
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp0_0_1]], i32 noundef 10, i32 noundef 2, i32 noundef 120, i32 noundef 103, ptr noundef @A.str) #6
+// CHECK-NEXT: %[[Ptr_Tmp0_1_0:.*]] = getelementptr [3 x [2 x %"class.hlsl::RWBuffer"]], ptr %tmp, i32 0, i32 1, i32 0
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp0_1_0]], i32 noundef 10, i32 noundef 2, i32 noundef 120, i32 noundef 104, ptr noundef @A.str) #6
+// CHECK-NEXT: %[[Ptr_Tmp0_1_1:.*]] = getelementptr [3 x [2 x %"class.hlsl::RWBuffer"]], ptr %tmp, i32 0, i32 1, i32 1
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp0_1_1]], i32 noundef 10, i32 noundef 2, i32 noundef 120, i32 noundef 105, ptr noundef @A.str) #6
+// CHECK-NEXT: %[[Ptr_Tmp0_2_0:.*]] = getelementptr [3 x [2 x %"class.hlsl::RWBuffer"]], ptr %tmp, i32 0, i32 2, i32 0
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp0_2_0]], i32 noundef 10, i32 noundef 2, i32 noundef 120, i32 noundef 106, ptr noundef @A.str) #6
+// CHECK-NEXT: %[[Ptr_Tmp0_2_1:.*]] = getelementptr [3 x [2 x %"class.hlsl::RWBuffer"]], ptr %tmp, i32 0, i32 2, i32 1
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp0_2_1]], i32 noundef 10, i32 noundef 2, i32 noundef 120, i32 noundef 107, ptr noundef @A.str) #6
+// After this Tmp0 values are copied to %Sub using the standard array loop initializaion
+// (generated from ArrayInitLoopExpr AST node)
+  RWBuffer<float> Sub[3][2] = A[4][1];
+
+// CHECK: %[[Ptr_Sub_2:.*]] = getelementptr inbounds  [3 x [2 x %"class.hlsl::RWBuffer"]], ptr %Sub, i32 0, i32 2
+// CHECK: %[[Ptr_Sub_2_1:.*]] = getelementptr inbounds [2 x %"class.hlsl::RWBuffer"], ptr %[[Ptr_Sub_2]], i32 0, i32 1
+// CHECK-NEXT: %[[BufPtr:.*]] = call {{.*}} ptr @_ZN4hlsl8RWBufferIfEixEj(ptr {{.*}} %[[Ptr_Sub_2_1]], i32 noundef 0)
+// CHECK-NEXT: %[[Sub_2_1_0_Value:.*]] = load float, ptr %[[BufPtr]], align 4
+// CHECK-NEXT: store float %[[Sub_2_1_0_Value]], ptr %a, align 4
+float a = Sub[2][1][0];
+
+// Codegen for "foo(A[2][GI])" - create local array [[Tmp2]] of size 3 x 2 and initialize
+// each element by a call to the resource constructor with dynamic index, and then
+// copy-in the array as an argument of "foo"
+
+// Calculate the resource index for A[2][GI][0][0] (index in the resource array as if it was flattened)
+// The index is 2 * (4 * 3 * 2) + GI * (3 * 2) = 48 + GI * 6
+// CHECK: %[[GI:.*]] = load i32, ptr %[[GI_alloca]], align 4
+// CHECK-NEXT: %[[Index_A_2_GI_Tmp:.*]] = mul i32 %[[GI]], 6
+// CHECK-NEXT: %[[Index_A_2_GI_0_0:.*]] = add i32 %[[Index_A_2_GI_Tmp]], 48
+
+// A[2][GI][0][0]
+// CHECK-NEXT: %[[Ptr_Tmp2_0_0:.*]] = getelementptr [3 x [2 x %"class.hlsl::RWBuffer"]], ptr %[[Tmp2]], i32 0, i32 0, i32 0
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp2_0_0]], i32 noundef 10, i32 noundef 2, i32 noundef 120, i32 noundef %[[Index_A_2_GI_0_0]], ptr noundef @A.str)
+
+// A[2][GI][0][1]
+// CHECK-NEXT: %[[Index_A_2_GI_0_1:.*]] = add i32 %[[Index_A_2_GI_0_0]], 1
+// CHECK-NEXT: %[[Ptr_Tmp2_0_1:.*]] = getelementptr [3 x [2 x %"class.hlsl::RWBuffer"]], ptr %[[Tmp2]], i32 0, i32 0, i32 1
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp2_0_1]], i32 noundef 10, i32 noundef 2, i32 noundef 120, i32 noundef %[[Index_A_2_GI_0_1]], ptr noundef @A.str)
+
+// A[2][GI][1][0]
+// CHECK-NEXT: %[[Index_A_2_GI_1_0:.*]] = add i32 %[[Index_A_2_GI_0_1]], 1
+// CHECK-NEXT: %[[Ptr_Tmp2_1_0:.*]] = getelementptr [3 x [2 x %"class.hlsl::RWBuffer"]], ptr %[[Tmp2]], i32 0, i32 1, i32 0
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp2_1_0]], i32 noundef 10, i32 noundef 2, i32 noundef 120, i32 noundef %[[Index_A_2_GI_1_0]], ptr noundef @A.str)
+
+// A[2][GI][1][1]
+// CHECK-NEXT: %[[Index_A_2_GI_1_1:.*]] = add i32 %[[Index_A_2_GI_1_0]], 1
+// CHECK-NEXT: %[[Ptr_Tmp2_1_1:.*]] = getelementptr [3 x [2 x %"class.hlsl::RWBuffer"]], ptr %[[Tmp2]], i32 0, i32 1, i32 1
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp2_1_1]], i32 noundef 10, i32 noundef 2, i32 noundef 120, i32 noundef %[[Index_A_2_GI_1_1]], ptr noundef @A.str)
+
+// A[2][GI][2][0]
+// CHECK-NEXT: %[[Index_A_2_GI_2_0:.*]] = add i32 %[[Index_A_2_GI_1_1]], 1
+// CHECK-NEXT: %[[Ptr_Tmp2_2_0:.*]] = getelementptr [3 x [2 x %"class.hlsl::RWBuffer"]], ptr %[[Tmp2]], i32 0, i32 2, i32 0
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp2_2_0]], i32 noundef 10, i32 noundef 2, i32 noundef 120, i32 noundef %[[Index_A_2_GI_2_0]], ptr noundef @A.str)
+
+// A[2][GI][2][1]
+// CHECK-NEXT: %[[Index_A_2_GI_2_1:.*]] = add i32 %[[Index_A_2_GI_2_0]], 1
+// CHECK-NEXT: %[[Ptr_Tmp2_2_1:.*]] = getelementptr [3 x [2 x %"class.hlsl::RWBuffer"]], ptr %[[Tmp2]], i32 0, i32 2, i32 1
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp2_2_1]], i32 noundef 10, i32 noundef 2, i32 noundef 120, i32 noundef %[[Index_A_2_GI_2_1]], ptr noundef @A.str)
+
+// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 4 %[[Tmp1]], ptr align 4 %[[Tmp2]], i32 24, i1 false)
+// CHECK-NEXT: %[[FooReturned:.*]] = call {{.*}} float @_Z3fooA3_A2_N4hlsl8RWBufferIfEE(ptr noundef byval([3 x [2 x %"class.hlsl::RWBuffer"]]) align 4 %[[Tmp1]])
+// CHECK-NEXT: store float %[[FooReturned]], ptr %b, align 4
+  float b = foo(A[2][GI]);
+
+  Out[0] = a + b;
+}

clang/test/CodeGenHLSL/resources/res-array-global-subarray-one.hlsl

@@ -0,0 +1,62 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.6-compute -finclude-default-header \
+// RUN:   -emit-llvm -disable-llvm-passes -o - %s | FileCheck %s
+
+// CHECK: @[[BufA:.*]] = private unnamed_addr constant [2 x i8] c"A\00", align 1
+
+RWBuffer<float> A[4][2] : register(u10, space2);
+RWStructuredBuffer<float> Out;
+
+float foo(RWBuffer<float> Arr[2]) {
+  return Arr[1][0];
+}
+
+// NOTE:
+// - _ZN4hlsl8RWBufferIfEC1EjjijPKc is the constructor call for explicit binding
+//    (has "jjij" in the mangled name) and the arguments are (register, space, range_size, index, name).
+// - _ZN4hlsl8RWBufferIfEixEj is the subscript operator for RWBuffer<float>
+
+// CHECK: define internal void @_Z4mainj(i32 noundef %GI)
+// CHECK-NEXT: entry:
+// CHECK-NEXT: %[[GI_alloca:.*]] = alloca i32, align 4
+// CHECK-NEXT: %Sub = alloca [2 x %"class.hlsl::RWBuffer"], align 4
+// CHECK-NEXT: %[[Tmp0:.*]] = alloca [2 x %"class.hlsl::RWBuffer"], align 4
+// CHECK-NEXT: %a = alloca float, align 4
+// CHECK-NEXT: %b = alloca float, align 4
+// CHECK-NEXT: %[[Tmp1:.*]] = alloca [2 x %"class.hlsl::RWBuffer"], align 4
+// CHECK-NEXT: %[[Tmp2:.*]] = alloca [2 x %"class.hlsl::RWBuffer"], align 4
+// CHECK-NEXT: store i32 %GI, ptr %[[GI_alloca]], align 4
+[numthreads(4,1,1)]
+void main(uint GI : SV_GroupThreadID) {
+// Codegen for "A[2]" - create local array [[Tmp0]] of size 2 and initialize
+// each element by a call to the resource constructor
+// CHECK-NEXT: %[[Ptr_Tmp0_0:.*]] = getelementptr [2 x %"class.hlsl::RWBuffer"], ptr %[[Tmp0]], i32 0, i32 0
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp0_0]], i32 noundef 10, i32 noundef 2, i32 noundef 8, i32 noundef 6, ptr noundef @A.str)
+// CHECK-NEXT: %[[Ptr_Tmp0_1:.*]] = getelementptr [2 x %"class.hlsl::RWBuffer"], ptr %[[Tmp0]], i32 0, i32 1
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp0_1]], i32 noundef 10, i32 noundef 2, i32 noundef 8, i32 noundef 7, ptr noundef @A.str)
+// After this Tmp0 values are copied to %Sub using the standard array loop initializaion
+// (generated from ArrayInitLoopExpr AST node)
+  RWBuffer<float> Sub[2] = A[3];
+
+// CHECK: %[[Ptr_Sub_1:.*]] = getelementptr inbounds [2 x %"class.hlsl::RWBuffer"], ptr %Sub, i32 0, i32 1
+// CHECK-NEXT: %[[BufPtr:.*]] = call {{.*}} ptr @_ZN4hlsl8RWBufferIfEixEj(ptr {{.*}} %[[Ptr_Sub_1]], i32 noundef 0)
+// CHECK-NEXT: %[[Sub_1_0_Value:.*]] = load float, ptr %[[BufPtr]], align 4
+// CHECK-NEXT: store float %[[Sub_1_0_Value]], ptr %a, align 4
+float a = Sub[1][0];
+
+// Codegen for "foo(A[GI])" - create local array [[Tmp2]] of size 2 and initialize
+// each element by a call to the resource constructor with dynamic index, and then
+// copy-in the array as an argument of "foo"
+// CHECK: %[[GI:.*]] = load i32, ptr %[[GI_alloca]], align 4
+// CHECK-NEXT: %[[Index_A_GI_0:.*]] = mul i32 %[[GI]], 2
+// CHECK-NEXT: %[[Ptr_Tmp2_GI_0:.*]] = getelementptr [2 x %"class.hlsl::RWBuffer"], ptr %[[Tmp2]], i32 0, i32 0
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp2_GI_0]], i32 noundef 10, i32 noundef 2, i32 noundef 8, i32 noundef %[[Index_A_GI_0]], ptr noundef @A.str)
+// CHECK-NEXT: %[[Index_A_GI_1:.*]] = add i32 %[[Index_A_GI_0]], 1
+// CHECK-NEXT: %[[Ptr_Tmp2_GI_1:.*]] = getelementptr [2 x %"class.hlsl::RWBuffer"], ptr %[[Tmp2]], i32 0, i32 1
+// CHECK-NEXT: call void @_ZN4hlsl8RWBufferIfEC1EjjijPKc(ptr {{.*}} %[[Ptr_Tmp2_GI_1]], i32 noundef 10, i32 noundef 2, i32 noundef 8, i32 noundef %[[Index_A_GI_1]], ptr noundef @A.str)
+// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 4 %[[Tmp1]], ptr align 4 %[[Tmp2]], i32 8, i1 false)
+// CHECK-NEXT: %[[FooReturned:.*]] = call {{.*}} float @_Z3fooA2_N4hlsl8RWBufferIfEE(ptr noundef byval([2 x %"class.hlsl::RWBuffer"]) align 4 %[[Tmp1]])
+// CHECK-NEXT: store float %[[FooReturned]], ptr %b, align 4
+  float b = foo(A[GI]);
+
+  Out[0] = a + b;
+}