Implement the GroupMemoryBarrier HLSL Function

[farzonl]

• Implement GroupMemoryBarrier clang builtin,
• Link GroupMemoryBarrier clang builtin with hlsl_intrinsics.h
• Add sema checks for GroupMemoryBarrier to CheckHLSLBuiltinFunctionCall in SemaChecking.cpp
• Add codegen for GroupMemoryBarrier to EmitHLSLBuiltinExpr in CGBuiltin.cpp
• Add codegen tests to clang/test/CodeGenHLSL/builtins/GroupMemoryBarrier.hlsl
• Add sema tests to clang/test/SemaHLSL/BuiltIns/GroupMemoryBarrier-errors.hlsl
• Create the int_dx_GroupMemoryBarrier intrinsic in IntrinsicsDirectX.td
• Create the DXILOpMapping of int_dx_GroupMemoryBarrier to 80 in DXIL.td
• Create the GroupMemoryBarrier.ll and GroupMemoryBarrier_errors.ll tests in llvm/test/CodeGen/DirectX/
• Create the int_spv_GroupMemoryBarrier intrinsic in IntrinsicsSPIRV.td
• In SPIRVInstructionSelector.cpp create the GroupMemoryBarrier lowering and map it to int_spv_GroupMemoryBarrier in SPIRVInstructionSelector::selectIntrinsic.
• Create SPIR-V backend test case in llvm/test/CodeGen/SPIRV/hlsl-intrinsics/GroupMemoryBarrier.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 GroupMemoryBarrier_test.hlsl -T lib_6_8 -enable-16bit-types -O0

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

HLSL:

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

Syntax

void GroupMemoryBarrier(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

 

See also

Intrinsic Functions

Shader Model 5