anv: Disable stencil writes when both write masks are zero

Vulkan doesn't have a stencilWriteEnable bit like it does for depth.
Instead, you have a stencil mask.  Since the stencil mask is handled as
dynamic state, we have to handle it later during command buffer
construction.  This, combined with a later commit, seems to help Dota2
on my Broadwell GT3e desktop by a couple percent because it allows the
hardware to move the depth and stencil writes to early in more cases.

Reviewed-by: Lionel Landwerlin <[email protected]>
Reviewed-by: Nanley Chery <[email protected]>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/intel/vulkan/genX_pipeline.c b/src/intel/vulkan/genX_pipeline.c
index 55d1e5571d7..f641661db1b 100644
--- a/src/intel/vulkan/genX_pipeline.c
+++ b/src/intel/vulkan/genX_pipeline.c
@@ -663,12 +663,15 @@ emit_ds_state(struct anv_pipeline *pipeline,
       /* We're going to OR this together with the dynamic state.  We need
        * to make sure it's initialized to something useful.
        */
+      pipeline->writes_stencil = false;
       memset(depth_stencil_dw, 0, sizeof(depth_stencil_dw));
       return;
    }
 
    /* VkBool32 depthBoundsTestEnable; // optional (depth_bounds_test) */
 
+   pipeline->writes_stencil = info->stencilTestEnable;
+
 #if GEN_GEN <= 7
    struct GENX(DEPTH_STENCIL_STATE) depth_stencil = {
 #else
@@ -680,7 +683,6 @@ emit_ds_state(struct anv_pipeline *pipeline,
       .DoubleSidedStencilEnable = true,
 
       .StencilTestEnable = info->stencilTestEnable,
-      .StencilBufferWriteEnable = info->stencilTestEnable,
       .StencilFailOp = vk_to_gen_stencil_op[info->front.failOp],
       .StencilPassDepthPassOp = vk_to_gen_stencil_op[info->front.passOp],
       .StencilPassDepthFailOp = vk_to_gen_stencil_op[info->front.depthFailOp],
@@ -707,7 +709,7 @@ emit_ds_state(struct anv_pipeline *pipeline,
    }
 
    if (!(aspects & VK_IMAGE_ASPECT_STENCIL_BIT)) {
-      depth_stencil.StencilBufferWriteEnable = false;
+      pipeline->writes_stencil = false;
       depth_stencil.StencilTestFunction = PREFILTEROPALWAYS;
       depth_stencil.BackfaceStencilTestFunction = PREFILTEROPALWAYS;
    }