v3d: Store the actual mask of color buffers present in the key.

If you only bound rt 1+, we'd still emit a write to the rt0 that isn't
present (noticed while debugging an
ext_framebuffer_multisample-alpha-to-coverage-no-draw-buffer-zero
regression in another change).

2 files changed, 6 insertions, 5 deletions

diff --git a/src/broadcom/compiler/nir_to_vir.c b/src/broadcom/compiler/nir_to_vir.c
index a5e75f650e8..d983f91e718 100644
--- a/src/broadcom/compiler/nir_to_vir.c
+++ b/src/broadcom/compiler/nir_to_vir.c
@@ -1129,8 +1129,8 @@ emit_frag_end(struct v3d_compile *c)
         */
 
         bool has_any_tlb_color_write = false;
-        for (int rt = 0; rt < c->fs_key->nr_cbufs; rt++) {
-                if (c->output_color_var[rt])
+        for (int rt = 0; rt < V3D_MAX_DRAW_BUFFERS; rt++) {
+                if (c->fs_key->cbufs & (1 << rt) && c->output_color_var[rt])
                         has_any_tlb_color_write = true;
         }
 
@@ -1194,8 +1194,8 @@ emit_frag_end(struct v3d_compile *c)
          * uniform setup
          */
 
-        for (int rt = 0; rt < c->fs_key->nr_cbufs; rt++) {
-                if (!c->output_color_var[rt])
+        for (int rt = 0; rt < V3D_MAX_DRAW_BUFFERS; rt++) {
+                if (!(c->fs_key->cbufs & (1 << rt)) || !c->output_color_var[rt])
                         continue;
 
                 nir_variable *var = c->output_color_var[rt];
diff --git a/src/broadcom/compiler/v3d_compiler.h b/src/broadcom/compiler/v3d_compiler.h
index 127b04136d1..cea26484a8f 100644
--- a/src/broadcom/compiler/v3d_compiler.h
+++ b/src/broadcom/compiler/v3d_compiler.h
@@ -357,7 +357,8 @@ struct v3d_fs_key {
         bool sample_alpha_to_one;
         bool clamp_color;
         bool shade_model_flat;
-        uint8_t nr_cbufs;
+        /* Mask of which color render targets are present. */
+        uint8_t cbufs;
         uint8_t swap_color_rb;
         /* Mask of which render targets need to be written as 32-bit floats */
         uint8_t f32_color_rb;