i965/fs: Rework the fs_visitor LOAD_PAYLOAD instruction
The newly reworked instruction is far more straightforward than the
original. Before, the LOAD_PAYLOAD instruction was lowered by a the
complicated and broken-by-design pile of heuristics to try and guess
force_writemask_all, exec_size, and a number of other factors on the
sources.
Instead, we use the header_size on the instruction to denote which sources
are "header sources". Header sources are required to be a single physical
hardware register that is copied verbatim. The registers that follow are
considered the actual payload registers and have a width that correspond's
to the LOAD_PAYLOAD's exec_size and are treated as being per-channel. This
gives us a fairly straightforward lowering:
1) All header sources are copied directly using force_writemask_all and,
since they are guaranteed to be a single register, there are no
force_sechalf issues.
2) All non-header sources are copied using the exact same force_sechalf
and force_writemask_all modifiers as the LOAD_PAYLOAD operation itself.
3) In order to accommodate older gens that need interleaved colors,
lower_load_payload detects when the destination is a COMPR4 register
and automatically interleaves the non-header sources. The
lower_load_payload pass does the right thing here regardless of whether
or not the hardware actually supports COMPR4.
This patch commit itself is made up of a bunch of smaller changes squashed
together. Individual change descriptions follow:
i965/fs: Rework fs_visitor::LOAD_PAYLOAD
We rework LOAD_PAYLOAD to verify that all of the sources that count as
headers are, indeed, exactly one register and that all of the non-header
sources match the destination width. We then take the exec_size for
LOAD_PAYLOAD directly from the destination width.
i965/fs: Make destinations of load_payload have the appropreate width
i965/fs: Rework fs_visitor::lower_load_payload
v2: Don't allow the saturate flag on LOAD_PAYLOAD instructions
i965/fs_cse: Support the new-style LOAD_PAYLOAD
i965/fs_inst::is_copy_payload: Support the new-style LOAD_PAYLOAD
i965/fs: Simplify setup_color_payload
Previously, setup_color_payload was a a big helper function that did a
lot of gen-specific special casing for setting up the color sources of
the LOAD_PAYLOAD instruction. Now that lower_load_payload is much more
sane, most of that complexity isn't needed anymore. Instead, we can do
a simple fixup pass for color clamps and then just stash sources
directly in the LOAD_PAYLOAD. We can trust lower_load_payload to do the
right thing with respect to COMPR4.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
4 files changed