NIR discard_if expects bools, therefore we end with extr CMP in
the end, however we can handle floats just fine (only with the
reversed logic, so it triggers for src < 0).
Shader-db RV530:
total instructions in shared programs: 120787 -> 120687 (-0.08%)
instructions in affected programs: 5559 -> 5459 (-1.80%)
helped: 102
HURT: 8
total temps in shared programs: 16770 -> 16764 (-0.04%)
temps in affected programs: 151 -> 145 (-3.97%)
helped: 8
HURT: 5
total cycles in shared programs: 181520 -> 181444 (-0.04%)
cycles in affected programs: 10932 -> 10856 (-0.70%)
helped: 101
HURT: 12
Signed-off-by: Pavel Ondračka <pavel.ondracka@gmail.com>
Reviewed-by: Filip Gawin <filip@gawin.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30967>