Implement the `DeviceMemoryBarrier` HLSL Function

[farzonl]

• Implement DeviceMemoryBarrier clang builtin,
• Link DeviceMemoryBarrier clang builtin with hlsl_intrinsics.h
• Add sema checks for DeviceMemoryBarrier to CheckHLSLBuiltinFunctionCall in SemaChecking.cpp
• Add codegen for DeviceMemoryBarrier to EmitHLSLBuiltinExpr in CGBuiltin.cpp
• Add codegen tests to clang/test/CodeGenHLSL/builtins/DeviceMemoryBarrier.hlsl
• Add sema tests to clang/test/SemaHLSL/BuiltIns/DeviceMemoryBarrier-errors.hlsl
• Create the int_dx_DeviceMemoryBarrier intrinsic in IntrinsicsDirectX.td
• Create the DXILOpMapping of int_dx_DeviceMemoryBarrier to 80 in DXIL.td
• Create the DeviceMemoryBarrier.ll and DeviceMemoryBarrier_errors.ll tests in llvm/test/CodeGen/DirectX/
• Create the int_spv_DeviceMemoryBarrier intrinsic in IntrinsicsSPIRV.td
• In SPIRVInstructionSelector.cpp create the DeviceMemoryBarrier lowering and map it to int_spv_DeviceMemoryBarrier in SPIRVInstructionSelector::selectIntrinsic.
• Create SPIR-V backend test case in llvm/test/CodeGen/SPIRV/hlsl-intrinsics/DeviceMemoryBarrier.ll

DirectX

DXIL Opcode	DXIL OpName	Shader Model	Shader Stages
80	Barrier	6.0	()

SPIR-V

OpMemoryBarrier:

Description:

Control the order that memory accesses are observed.

Ensures that memory accesses issued before this instruction are observed
before memory accesses issued after this instruction. This control is
ensured only for memory accesses issued by this
invocation and observed by another invocation executing
within Memory scope. If the Vulkan memory model
is declared, this ordering only applies to memory accesses that use the
NonPrivatePointer memory operand or
NonPrivateTexel image operand.

Semantics declares what kind of memory is being controlled and what
kind of control to apply.

To execute both a memory barrier and a control barrier, see
OpControlBarrier.

Word Count	Opcode	Results	Operands
3	225	Scope <id> Memory	Memory Semantics <id> Semantics

Test Case(s)

Example 1

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

export void fn() {
    return DeviceMemoryBarrier();
}

HLSL:

Blocks execution of all threads in a group until all device memory accesses have been completed.

Syntax

void DeviceMemoryBarrier(void);

Parameters

This function has no parameters.

Return value

This function does not return a value.

Remarks

Minimum Shader Model

This function is supported in the following shader models.

Shader Model	Supported
Shader Model 5 and higher shader models	yes

 

This function is supported in the following types of shaders:

Vertex	Hull	Domain	Geometry	Pixel	Compute
				x	x

 

See also

Intrinsic Functions

Shader Model 5