anv: ensure null-rt bit in compiler isn't used when there is ds attachment

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: 15987f49bb ("anv: avoid setting up a null RT unless needed")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/12396
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
(cherry picked from commit 98cdb9349a)

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33113>

.pick_status.json

@@ -204,7 +204,7 @@
         "description": "anv: ensure null-rt bit in compiler isn't used when there is ds attachment",
         "nominated": true,
         "nomination_type": 2,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "15987f49bb9ca105f7b252d90349f614c492c3d5",
         "notes": null

src/intel/vulkan/anv_pipeline.c

@@ -531,6 +531,15 @@ rp_color_mask(const struct vk_render_pass_state *rp)
          color_mask |= BITFIELD_BIT(i);
    }
 
+   /* If there is depth/stencil attachment, even if the fragment shader
+    * doesn't write the depth/stencil output, we need a valid render target so
+    * that the compiler doesn't use the null-rt which would cull the
+    * depth/stencil output.
+    */
+   if (rp->depth_attachment_format != VK_FORMAT_UNDEFINED ||
+       rp->stencil_attachment_format != VK_FORMAT_UNDEFINED)
+      color_mask |= 1;
+
    return color_mask;
 }