Implement the GetRenderTargetSampleCount HLSL Function

[farzonl]

• Implement GetRenderTargetSampleCount clang builtin,
• Link GetRenderTargetSampleCount clang builtin with hlsl_intrinsics.h
• Add sema checks for GetRenderTargetSampleCount to CheckHLSLBuiltinFunctionCall in SemaChecking.cpp
• Add codegen for GetRenderTargetSampleCount to EmitHLSLBuiltinExpr in CGBuiltin.cpp
• Add codegen tests to clang/test/CodeGenHLSL/builtins/GetRenderTargetSampleCount.hlsl
• Add sema tests to clang/test/SemaHLSL/BuiltIns/GetRenderTargetSampleCount-errors.hlsl
• Create the int_dx_GetRenderTargetSampleCount intrinsic in IntrinsicsDirectX.td
• Create the DXILOpMapping of int_dx_GetRenderTargetSampleCount to 77 in DXIL.td
• Create the GetRenderTargetSampleCount.ll and GetRenderTargetSampleCount_errors.ll tests in llvm/test/CodeGen/DirectX/

DirectX

DXIL Opcode	DXIL OpName	Shader Model	Shader Stages
77	RenderTargetGetSampleCount	6.0	('pixel',)

SPIR-V

There is no support for GetRenderTargetSampleCount when targeting SPIR-V.

Test Case(s)

Example 1

//dxc GetRenderTargetSampleCount_test.hlsl -T lib_6_8 -enable-16bit-types -O0

[numthreads(1, 1, 1)]
[shader("pixel")]
uint fn( ) : SV_Target {

	return GetRenderTargetSampleCount();
}

HLSL:

Gets the number of samples for a render target.

UINT GetRenderTargetSampleCount()

Parameters

Item	Description
None

Return Value

The number of samples.

Remarks

Use this function and GetRenderTargetSamplePosition to find out the number and position of the sampling locations for a render target.

Minimum Shader Model

This function is supported in the following shader models.

Shader Model	Supported
Shader Model 4 and higher shader models	yes
Shader Model 3 (DirectX HLSL)	no
Shader Model 2 (DirectX HLSL)	no
Shader Model 1 (DirectX HLSL)	no

See also

Intrinsic Functions (DirectX HLSL)