[DirectX] Add llvm.dx.resource.getdimensions.x intrinsic and lowering to DXIL

llvm/include/llvm/IR/IntrinsicsDirectX.td

@@ -77,6 +77,9 @@ def int_dx_resource_updatecounter
     : DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_any_ty, llvm_i8_ty],
                             [IntrInaccessibleMemOrArgMemOnly]>;
 
+def int_dx_resource_getdimensions_x
+    : DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_any_ty], [IntrReadMem]>;
+
 // Cast between target extension handle types and dxil-style opaque handles
 def int_dx_resource_casthandle : Intrinsic<[llvm_any_ty], [llvm_any_ty]>;
 

llvm/include/llvm/IR/IntrinsicsSPIRV.td

@@ -159,6 +159,9 @@ def int_spv_rsqrt : DefaultAttrsIntrinsic<[LLVMMatchType<0>], [llvm_anyfloat_ty]
       : DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_any_ty, llvm_i8_ty],
                               [IntrInaccessibleMemOrArgMemOnly]>;
 
+  def int_spv_resource_getdimensions_x
+      : DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_any_ty], [IntrReadMem]>;
+
   def int_spv_resource_getpointer
       : DefaultAttrsIntrinsic<[llvm_anyptr_ty], [llvm_any_ty, llvm_i32_ty],
                               [IntrNoMem]>;

llvm/lib/Target/DirectX/DXIL.td

@@ -57,6 +57,7 @@ def ResBindTy : DXILOpParamType;
 def ResPropsTy : DXILOpParamType;
 def SplitDoubleTy : DXILOpParamType;
 def BinaryWithCarryTy : DXILOpParamType;
+def DimensionsTy : DXILOpParamType;
 
 class DXILOpClass;
 
@@ -901,6 +902,13 @@ def CheckAccessFullyMapped : DXILOp<71, checkAccessFullyMapped> {
   let attributes = [Attributes<DXIL1_0, [ReadOnly]>];
 }
 
+def GetDimensions : DXILOp<72, getDimensions> {
+  let Doc = "gets the dimensions of a buffer or texture";
+  let arguments = [HandleTy, Int32Ty];
+  let result = DimensionsTy;
+  let stages = [Stages<DXIL1_0, [all_stages]>];
+}
+
 def Barrier : DXILOp<80, barrier> {
   let Doc = "inserts a memory barrier in the shader";
   let intrinsics = [

llvm/lib/Target/DirectX/DXILOpBuilder.cpp

@@ -261,6 +261,12 @@ static StructType *getBinaryWithCarryType(LLVMContext &Context) {
   return StructType::create({Int32Ty, Int1Ty}, "dx.types.i32c");
 }
 
+static StructType *getDimensionsType(LLVMContext &Ctx) {
+  Type *Int32Ty = Type::getInt32Ty(Ctx);
+  return getOrCreateStructType("dx.types.Dimensions",
+                               {Int32Ty, Int32Ty, Int32Ty, Int32Ty}, Ctx);
+}
+
 static Type *getTypeFromOpParamType(OpParamType Kind, LLVMContext &Ctx,
                                     Type *OverloadTy) {
   switch (Kind) {
@@ -318,6 +324,8 @@ static Type *getTypeFromOpParamType(OpParamType Kind, LLVMContext &Ctx,
     return getSplitDoubleType(Ctx);
   case OpParamType::BinaryWithCarryTy:
     return getBinaryWithCarryType(Ctx);
+  case OpParamType::DimensionsTy:
+    return getDimensionsType(Ctx);
   }
   llvm_unreachable("Invalid parameter kind");
   return nullptr;

llvm/lib/Target/DirectX/DXILOpLowering.cpp

@@ -627,6 +627,28 @@ class OpLowerer {
     });
   }
 
+  [[nodiscard]] bool lowerGetDimensionsX(Function &F) {
+    IRBuilder<> &IRB = OpBuilder.getIRB();
+    Type *Int32Ty = IRB.getInt32Ty();
+
+    return replaceFunction(F, [&](CallInst *CI) -> Error {
+      IRB.SetInsertPoint(CI);
+      Value *Handle =
+          createTmpHandleCast(CI->getArgOperand(0), OpBuilder.getHandleType());
+      Value *Undef = UndefValue::get(Int32Ty);
+
+      Expected<CallInst *> OpCall = OpBuilder.tryCreateOp(
+          OpCode::GetDimensions, {Handle, Undef}, CI->getName(), Int32Ty);
+      if (Error E = OpCall.takeError())
+        return E;
+      Value *Dim = IRB.CreateExtractValue(*OpCall, 0);
+
+      CI->replaceAllUsesWith(Dim);
+      CI->eraseFromParent();
+      return Error::success();
+    });
+  }
+
   [[nodiscard]] bool lowerGetPointer(Function &F) {
     // These should have already been handled in DXILResourceAccess, so we can
     // just clean up the dead prototype.
@@ -934,6 +956,9 @@ class OpLowerer {
       case Intrinsic::dx_resource_updatecounter:
         HasErrors |= lowerUpdateCounter(F);
         break;
+      case Intrinsic::dx_resource_getdimensions_x:
+        HasErrors |= lowerGetDimensionsX(F);
+        break;
       case Intrinsic::ctpop:
         HasErrors |= lowerCtpopToCountBits(F);
         break;

llvm/test/CodeGen/DirectX/bufferGetDimensions.ll

@@ -0,0 +1,16 @@
+; RUN: opt -S -dxil-op-lower %s | FileCheck %s
+
+target triple = "dxil-pc-shadermodel6.6-compute"
+
+define i32 @test_getdimensions_no_mips() {
+  ; CHECK: %[[HANDLE:.*]] = call %dx.types.Handle @dx.op.createHandleFromBinding(i32 217, 
+  ; CHECK-NEXT: %[[ANNOT_HANDLE:.*]] = call %dx.types.Handle @dx.op.annotateHandle(i32 216, %dx.types.Handle %[[HANDLE]]
+  %handle = call target("dx.TypedBuffer", <4 x float>, 0, 0, 0) @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr null)
+
+  ; CHECK-NEXT: %[[RETVAL:.*]] = call %dx.types.Dimensions @dx.op.getDimensions(i32 72, %dx.types.Handle %[[ANNOT_HANDLE]], i32 undef)
+  ; CHECK-NEXT: %[[DIM:.*]] = extractvalue %dx.types.Dimensions %[[RETVAL]], 0
+  %1 = call i32 @llvm.dx.resource.getdimensions.x(target("dx.TypedBuffer", <4 x float>, 0, 0, 0) %handle)
+
+  ; CHECK-NEXT: ret i32 %[[DIM]]
+  ret i32 %1
+}