Implement the `normalize` HLSL Function

[farzonl]

• Implement normalize clang builtin,
• Link normalize clang builtin with hlsl_intrinsics.h
• Add sema checks for normalize to CheckHLSLBuiltinFunctionCall in SemaChecking.cpp
• Add codegen for normalize to EmitHLSLBuiltinExpr in CGBuiltin.cpp
• Add codegen tests to clang/test/CodeGenHLSL/builtins/normalize.hlsl
• Add sema tests to clang/test/SemaHLSL/BuiltIns/normalize-errors.hlsl
• Create the int_dx_normalize intrinsic in IntrinsicsDirectX.td
• Create an intrinsic expansion int_dx_normalize in llvm/lib/Target/DirectX/DXILIntrinsicExpansion.cpp
• Create the normalize.ll and normalize_errors.ll tests in llvm/test/CodeGen/DirectX/
• Create the int_spv_normalize intrinsic in IntrinsicsSPIRV.td
• In SPIRVInstructionSelector.cpp create the normalize lowering and map it to int_spv_normalize in SPIRVInstructionSelector::selectIntrinsic.
• Create SPIR-V backend test case in llvm/test/CodeGen/SPIRV/hlsl-intrinsics/normalize.ll

DirectX

DXIL Opcode	DXIL OpName	Shader Model	Shader Stages
56	Dot4	6.0	()

SPIR-V

Normalize:

Description:

Normalize

Result is the vector in the same direction as x but with a length of
1.

The operand x must be a scalar or vector whose component type is
floating-point.

Result Type and the type of x must be the same type.

Number	Operand 1	Operand 2	Operand 3	Operand 4
69	<id> x

Test Case(s)

Example 1

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

export float4 fn(float4 p1) {
    return normalize(p1);
}

HLSL:

Normalizes the specified floating-point vector according to x / length(x).

ret normalize(x)

Parameters

Item	Description
x	[in] The specified floating-point vector.

Return Value

The normalized x parameter. If the length of the x parameter is 0, the result is indefinite.

Remarks

The normalize HLSL intrinsic function uses the following formula: x / length(x).

Type Description

Name	Template Type	Component Type	Size
x	vector	float	any
ret	same as input x	float	same dimension(s) as input x

Minimum Shader Model

This function is supported in the following shader models.

Shader Model	Supported
Shader Model 2 (DirectX HLSL) and higher shader models	yes
Shader Model 1 (DirectX HLSL)	yes (vs_1_1 only)

See also

Intrinsic Functions (DirectX HLSL)