Previously, the code to copy g0 to the message header existed in two
places - one for the texture offset case, and one for any other case.
By treating texture_offset as a special case of header_present, we can
remove this duplication and shorten the code. Future patches which add
new header fields also won't have to add additional duplication.
This also clarifies a confusing construct. The old code contained:
} else if (inst->header_present) {
if (brw->gen >= 7) {
...explicit copy from g0 to the message header...
} else {
/* Set up an implied move from g0 to the MRF. */
}
}
This looks like it might set up an implied move on Sandybridge, which
doesn't support those. However, Sandybridge only uses a message header
for texture offsets, so it would never hit this code path. The new code
avoids this implicit knowledge by only setting up an implied move on
Gen4-5.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Chris Forbes <chrisf@ijw.co.nz>
Kenneth Graunke
ebfe43d5ad