Alyssa Rosenzweig
f4b3201244
load_preamble is intended to be almost free (costing at most a move), and it
does not have special bounds checking requirement, so it's ok to select with it.
With this, drivers that use nir_opt_preamble together with a late call to
peephole_select can optimize sequences like:
if (x) {
<uniform-on-uniform calculation>
} else {
<different uniform-on-uniform calculation>
}
to simply
bcsel(x, <uniform register 0>, <uniform register 1>)
rather than emitting needless control flow / branching over some moves.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Jason Ekstrand <jason.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20597>