Deprecating GLSLstd450Radians and GLSLstd450Degrees?

[alister-chowdhury]

Given the definition from the spec:

Radians

Converts degrees to radians, i.e., degrees * 𝜋 / 180.
The operand degrees must be a scalar or vector whose component type is 16-bit or 32-bit floating-point.
Result Type and the type of degrees must be the same type. Results are computed per component.

Degrees

Converts radians to degrees, i.e., radians * 180 / 𝜋.
The operand radians must be a scalar or vector whose component type is 16-bit or 32-bit floating-point.
Result Type and the type of radians must be the same type. Results are computed per component.

Both of these instruction are simply short hand for a OpFMul or OpVectorTimesScalar, with the extra caveat of being limited to only 16bit or 32bit floats.
This certainly doesn't seem like something that needs its own instruction?
Additionally any use of it would currently not get folded by spirv-opt, (although a rule could be added to convert it so things like reassociation can happen later).

Many thanks,
Alister

[gnl21]

The working group discussed this and agreed to deprecate these instructions. We'll update the extended instruction spec.