iris: Don't check VF address high bits when there is no buffer.

If there is no buffer, then it doesn't matter.  Leave the old stale
high bits in place (for next time) and don't bother invalidating.

Cuts 5.6% of the flushes in the Civilization VI demo on Kabylake GT2.

diff --git a/src/gallium/drivers/iris/iris_blorp.c b/src/gallium/drivers/iris/iris_blorp.c
index 209940e9bc788ff1aadc5eb061268b8440be444b..ede679e731af0002d05157def0640731a7e5b7ea 100644 (file)
--- a/src/gallium/drivers/iris/iris_blorp.c
+++ b/src/gallium/drivers/iris/iris_blorp.c
@@ -212,7 +212,7 @@ blorp_vf_invalidate_for_vb_48b_transitions(struct blorp_batch *blorp_batch,
       struct iris_bo *bo = addrs[i].buffer;
       uint16_t high_bits = bo ? bo->gtt_offset >> 32u : 0;
 
-      if (high_bits != ice->state.last_vbo_high_bits[i]) {
+      if (bo && high_bits != ice->state.last_vbo_high_bits[i]) {
          need_invalidate = true;
          ice->state.last_vbo_high_bits[i] = high_bits;
       }