Otherwise writes get propagated across atomics if no barrier is
used. Without barrier writes should still be visible in the same
invocation, so an atomic has to be considered a write.
CC: <mesa-stable@lists.freedesktop.org>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Fixes: b3c6146925 "nir: Copy propagation between blocks"
Fixes: 62332d139c "nir: Add a local variable-based copy propagation pass"
8424cd8fbd