SPV_EXT_physical_storage_buffer aliasing decorations

Why are the aliasing/restrict decorations supposed to go on OpVariable, and how does that work? You can eliminate all your local OpVariables through mem2reg. My pointers are loaded from a PushConstant, and don't even have an OpVariable. What is their aliasing behavior?

It makes more sense to make aliasing a storage class: PhysicalStorageRestrict and PhysicalStorageAliased. This way it won't fall off under CFG transformations.

Start by reviewing the SPV_EXT_physical_storage_buffer specification and the stated behavior of aliasing/restrict decorations on OpVariable, including pointers loaded from PushConstant and effects of mem2reg and CFG transformations. Done requires a settled specification decision on their aliasing behavior and whether PhysicalStorageRestrict and PhysicalStorageAliased storage classes are appropriate.

Written by the indexing model from the issue text.