freedreno/a6xx: fix blend all_mrt_write_mask

Fix all_mrt_write_mask when independent_blend_enable is false.
Otherwise, lrz write is always diabled with MRT when
independent_blend_enable is false.  This fixes a 2% perf regression for
multiple gfxbench benchmarks.

Fixes: 0132c22de75 ("freedreno/a6xx: Don't disable LRZ for invalid channels")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20254>

diff --git a/src/gallium/drivers/freedreno/a6xx/fd6_blend.c b/src/gallium/drivers/freedreno/a6xx/fd6_blend.c
index 7827307..2b49ebd 100644 (file)
--- a/src/gallium/drivers/freedreno/a6xx/fd6_blend.c
+++ b/src/gallium/drivers/freedreno/a6xx/fd6_blend.c
@@ -170,9 +170,9 @@ fd6_blend_state_create(struct pipe_context *pctx,
    STATIC_ASSERT((4 * PIPE_MAX_COLOR_BUFS) == (8 * sizeof(so->all_mrt_write_mask)));
    so->all_mrt_write_mask = 0;
 
-   unsigned nr = cso->independent_blend_enable ? cso->max_rt : 0;
-   for (unsigned i = 0; i <= nr; i++) {
-      const struct pipe_rt_blend_state *rt = &cso->rt[i];
+   for (unsigned i = 0; i <= cso->max_rt; i++) {
+      const struct pipe_rt_blend_state *rt =
+         &cso->rt[cso->independent_blend_enable ? i : 0];
 
       so->reads_dest |= rt->blend_enable;