The group implicity selects which flags the instruction can write. This
was discovered while working on another set of changes that could change
some logical operations into predicated MOV instructions.
Prevents regressions later in the series in
dEQP-VK.graphicsfuzz.cov-loop-fragcoord-identical-condition.
No shader-db or fossil-db changes on any Intel platform.
v2: Update the comment in the test case. Suggested by Caio.
Fixes: 95ac3b1dae ("i965/fs: don't propagate cmod when the exec sizes differ")
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38315>
(cherry picked from commit ba30794847)
fe2f91e005