nir: Redefine start/end_ip of blocks to fix NIR-to-TGSI liveness bugs.
With the block's end_ip accidentally being the ip of the next instruction,
contrary to the comment, you would end up doing end-of-block freeing early
and have the value missing when it came time to emit the next instruction.
Just expand the ips to have separate ones for start and end of block --
while it means that nir_instr->index is no longer incremented by 1 per
instruction, it makes sense for use in liveness because a backend is
likely to need to do other things at block boundaries (like emit the if
statement's code), and having an ip to identify that stuff is useful.
Fixes: a206b581578d ("nir: Add a block start/end ip to live instr index metadata.")
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7658>
(cherry picked from commit d3d28f6c2d1795d391442249343d8cd38356665d)
5 files changed