This pass (lowering discard_if to control flow and unconditional
discard) was originally written for Zink, but is useful for hardware
that lacks conditional discard instructions like AGX. In theory AGX
could implement a conditional discard with CSEL, but the vendor
compiler uses a lowering like this one. Since I like not writing code,
I'd like to use the pass that's already in tree.
v2: Don't preserve dominance (Jason). Assert we don't see demotes or
terminates (Jason). Add Mike's ack.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Acked-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14217>
Alyssa Rosenzweig