It is invalid if the same decoration is applied to the same id multiple
times. This adds a check before adding a decoration that the decoration
is not already in the list. If it is, then the duplicate is not added.
Fixes#3627
Add command line support which enables the following behavior:
- Remap discard
Map discard to DemoteToHelperInvocation for HLSL shaders. Map to
OpTerminateInvocation for GLSL shaders.
- Decorate HelperInvocation with Volatile
- Use localSizeId for execution mode
WorkGroupSize is deprecated in spirv1.6
Also update known goods to SPIRV 1.6