Simple greedy thing that has the potential to inflate register pressure but
reduces instructions. Thanks to the recent loop work that turns if { break }
into while_icmp, this also implicitly handles fusing conditions into loops,
which is what actually prompted this.
Surprisingly, this helps register pressure on my shader-db (no change to thread
count), I guess by eliminating the boolean temps in case where the sources are
used multiple times.
total instructions in shared programs: 1786561 -> 1784943 (-0.09%)
instructions in affected programs: 128557 -> 126939 (-1.26%)
helped: 474
HURT: 13
Instructions are helped.
total bytes in shared programs: 11733236 -> 11720734 (-0.11%)
bytes in affected programs: 976034 -> 963532 (-1.28%)
helped: 521
HURT: 13
Bytes are helped.
total halfregs in shared programs: 474245 -> 474094 (-0.03%)
halfregs in affected programs: 1869 -> 1718 (-8.08%)
helped: 28
HURT: 7
Halfregs are helped.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25052>
Alyssa Rosenzweig
e7ffc799d1