Implement the WaveMultiPrefixCountBits HLSL Function

[farzonl]

• Implement WaveMultiPrefixCountBits clang builtin,
• Link WaveMultiPrefixCountBits clang builtin with hlsl_intrinsics.h
• Add sema checks for WaveMultiPrefixCountBits to CheckHLSLBuiltinFunctionCall in SemaChecking.cpp
• Add codegen for WaveMultiPrefixCountBits to EmitHLSLBuiltinExpr in CGBuiltin.cpp
• Add codegen tests to clang/test/CodeGenHLSL/builtins/WaveMultiPrefixCountBits.hlsl
• Add sema tests to clang/test/SemaHLSL/BuiltIns/WaveMultiPrefixCountBits-errors.hlsl
• Create the int_dx_WaveMultiPrefixCountBits intrinsic in IntrinsicsDirectX.td
• Create the DXILOpMapping of int_dx_WaveMultiPrefixCountBits to 167 in DXIL.td
• Create the WaveMultiPrefixCountBits.ll and WaveMultiPrefixCountBits_errors.ll tests in llvm/test/CodeGen/DirectX/

DirectX

DXIL Opcode	DXIL OpName	Shader Model	Shader Stages
167	WaveMultiPrefixBitCount	6.5	('library', 'compute', 'amplification', 'mesh', 'pixel', 'vertex', 'hull', 'domain', 'geometry', 'raygeneration', 'intersection', 'anyhit', 'closesthit', 'miss', 'callable', 'node')

SPIR-V

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

Test Case(s)

Example 1

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

export uint fn(bool p1, uint4 p2) {
    return WaveMultiPrefixCountBits(p1, p2);
}

HLSL:

Syntax

uint WaveMultiPrefixCountBits(bool value, uint<4> mask);

Type Description

Name	Template Type	Component Type	Size
ret	scalar	uint	1
value	scalar	bool	1
mask	vector	uint	4

Minimum Shader Model

This function is supported in the following shader models.

Shader Model	Supported
Shader Model 6.5 and higher shader models	yes

Shader Stages

• Library Shader
• Compute Shader
• Amplification Shader
• Mesh Shader
• Pixel Shader
• Vertex Shader
• Hull Shader
• Domain Shader
• Geometry Shader
• Raygeneration Shader
• Intersection Shader
• Anyhit Shader
• Closesthit Shader
• Miss Shader
• Callable Shader
• Node Shader

See also

• Intrinsic Functions (DirectX HLSL)
• See WaveMultiPrefix*() Functions