These rules are under "Data Rules" in 2.16.1 (Universal Validation
Rules) part of the SPIR-V 1.1 Specification document:
* Scalar floating-point types can be parameterized only as 32 bit, plus
any additional sizes enabled by capabilities.
* Scalar integer types can be parameterized only as 32 bit, plus any
additional sizes enabled by capabilities.
* Vector types can only be parameterized with numerical types or the
OpTypeBool type.
* Matrix types can only be parameterized with floating-point types.
* Matrix types can only be parameterized as having only 2, 3, or 4
columns.
* Specialization constants (see Specialization) are limited to integers,
Booleans, floating-point numbers, and vectors of these.