This *almost* matches what GLSL wants, except for the handling of
large widths. You can see this in the lowering algorithm:
(('bitfield_insert', 'base', 'insert', 'offset', 'bits'),
('bcsel', ('ult', 31, 'bits'), 'insert',
('bfi', ('bfm', 'bits', 'offset'), 'insert', 'base')),
'options->lower_bitfield_insert'),
DXIL's 'bfi' instruction is an inseparable pairing of NIR's 'bfi(bfm(...), ...)',
so we just apply the additional bcsel in the backend.
Reviewed-by: Sil Vilerino <sivileri@microsoft.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14624>
Jesse Natalie
80e782d5ed