• Implement ldexp entirely in hlsl_intrinsics.h and other hlsl headers.
• Implement ldexp codgen tests in clang/test/CodeGenHLSL/builtins/ldexp.hlsl
• Implement ldexp sema tests in clang/test/SemaHLSL/BuiltIns/ldexp-errors.hlsl

https://hlsl.godbolt.org/z/97c4GxGrP

Implementation should look something like this:

template <typename T, int N>
constexpr T ldexp(T p0, T p1) {
  return  exp2(p1) * p0;
}

DirectX

SPIR-V

Exp2:

Description:

Exp2

Result is 2 raised to the x power; 2^x.

The operand x must be a scalar or vector whose component type is
16-bit or 32-bit floating-point.

Result Type and the type of x must be the same type. Results are
computed per component.

Test Case(s)

Example 1

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

export float4 fn(float4 p1, float4 p2) {
    return ldexp(p1, p2);
}

HLSL:

Returns the result of multiplying the specified value by two, raised to the power of the specified exponent.

This function uses the following formula: x * 2^exp

Parameters

Return Value

The result of multiplying the x parameter by two, raised to the power of the exp parameter.

Type Description

Minimum Shader Model

This function is supported in the following shader models.

Requirements

See also

Intrinsic Functions (DirectX HLSL)