Eduardo Lima Mitev authored Jul 01, 2017 and José María Casanova Crespo committed Dec 06, 2017

Adds new INT16, UINT16 and FLOAT16 base types.

The corresponding GL types for half floats were reused from the
AMD_gpu_shader_half_float extension. The int16 and uint16 types come from
NV_gpu_shader_5 extension.

This adds the builtins and the lexer support.

To avoid a bunch of warnings due to cases not handled in switch, the
new types have been added to a few places using same behavior as
their 32-bit counterparts, except for a few trivial cases where they are
already handled properly. Subsequent patches in this set will provide
correct 16-bit implementations when needed.

v2: * Use FLOAT16 instead of HALF_FLOAT as name of the base type.
    * Removed float16_t from builtin types.
    * Don't copy 16-bit types as if they were 32-bit values in
      copy_constant_to_storage().
    * Use get_scalar_type() instead of adding a new custom switch
      statement.
    (Jason Ekstrand)
v3: Use GL_FLOAT16_NV instead of GL_HALF_FLOAT for consistency
    (Ilia Mirkin)
v4: Add missing 16-bit base types support in glsl_to_nir (Eduardo Lima).
v5: Fix coding style (Topi Poholainen).

Signed-off-by: Jose Maria Casanova Crespo <jmcasanova@igalia.com>
Signed-off-by: Eduardo Lima <elima@igalia.com>
Signed-off-by: Alejandro Piñeiro <apinheiro@igalia.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>