radv: workaround WWZ exporting index=1 through location=1

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Georg Lehmann <dadschoorse@gmail.com>
Fixes: 290c3d360e ("aco,radv: lower outputs to exports when nir for monolithic ps")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/9232
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24354>

src/amd/vulkan/radv_instance.c

@@ -150,6 +150,7 @@ static const driOptionDescription radv_dri_options[] = {
       DRI_CONF_RADV_TEX_NON_UNIFORM(false)
       DRI_CONF_RADV_FLUSH_BEFORE_TIMESTAMP_WRITE(false)
       DRI_CONF_RADV_RT_WAVE64(false)
+      DRI_CONF_DUAL_COLOR_BLEND_BY_LOCATION(false)
       DRI_CONF_RADV_APP_LAYER()
    DRI_CONF_SECTION_END
 };
@@ -206,6 +207,8 @@ radv_init_dri_options(struct radv_instance *instance)
       driQueryOptionb(&instance->dri_options, "radv_flush_before_timestamp_write");
 
    instance->force_rt_wave64 = driQueryOptionb(&instance->dri_options, "radv_rt_wave64");
+
+   instance->dual_color_blend_by_location = driQueryOptionb(&instance->dri_options, "dual_color_blend_by_location");
 }
 
 static const struct vk_instance_extension_table radv_instance_extensions_supported = {

src/amd/vulkan/radv_pipeline.c

@@ -260,6 +260,8 @@ radv_get_hash_flags(const struct radv_device *device, bool stats)
       hash_flags |= RADV_HASH_SHADER_NGG_STREAMOUT;
    if (device->instance->debug_flags & RADV_DEBUG_NO_RT)
       hash_flags |= RADV_HASH_SHADER_NO_RT;
+   if (device->instance->dual_color_blend_by_location)
+      hash_flags |= RADV_HASH_SHADER_DUAL_BLEND_MRT1;
    return hash_flags;
 }
 

src/amd/vulkan/radv_private.h

@@ -410,6 +410,7 @@ struct radv_instance {
    bool tex_non_uniform;
    bool flush_before_timestamp_write;
    bool force_rt_wave64;
+   bool dual_color_blend_by_location;
    char *app_layer;
 };
 
@@ -2122,6 +2123,7 @@ struct radv_event {
 #define RADV_HASH_SHADER_NO_FMASK        (1 << 19)
 #define RADV_HASH_SHADER_NGG_STREAMOUT   (1 << 20)
 #define RADV_HASH_SHADER_NO_RT           (1 << 21)
+#define RADV_HASH_SHADER_DUAL_BLEND_MRT1 (1 << 22)
 
 struct radv_pipeline_key;
 struct radv_ray_tracing_group;

src/amd/vulkan/radv_shader.c

@@ -325,6 +325,24 @@ is_not_xfb_output(nir_variable *var, void *data)
    return !var->data.explicit_xfb_buffer && !var->data.explicit_xfb_stride;
 }
 
+/* If the shader doesn't have an index=1 output, then assume that it meant for a location=1 to be used. This works on
+ * some older hardware because the MRT1 target is used for both location=1 and index=1, but GFX11 works differently.
+ */
+static void
+fix_dual_src_mrt1_export(nir_shader *nir)
+{
+   nir_foreach_shader_out_variable (var, nir) {
+      if (var->data.location == FRAG_RESULT_DATA0 && var->data.index == 1)
+         return;
+   }
+
+   nir_variable *loc1_var = nir_find_variable_with_location(nir, nir_var_shader_out, FRAG_RESULT_DATA1);
+   if (loc1_var) {
+      loc1_var->data.location = FRAG_RESULT_DATA0;
+      loc1_var->data.index = 1;
+   }
+}
+
 nir_shader *
 radv_shader_spirv_to_nir(struct radv_device *device, const struct radv_shader_stage *stage,
                          const struct radv_pipeline_key *key, bool is_internal)
@@ -510,6 +528,10 @@ radv_shader_spirv_to_nir(struct radv_device *device, const struct radv_shader_st
       NIR_PASS(_, nir, nir_remove_dead_variables,
                nir_var_shader_in | nir_var_shader_out | nir_var_system_value | nir_var_mem_shared, &dead_vars_opts);
 
+      if (nir->info.stage == MESA_SHADER_FRAGMENT && key->ps.epilog.mrt0_is_dual_src &&
+          device->instance->dual_color_blend_by_location)
+         fix_dual_src_mrt1_export(nir);
+
       /* Variables can make nir_propagate_invariant more conservative
        * than it needs to be.
        */

src/util/00-radv-defaults.conf

@@ -105,6 +105,7 @@ Application bugs worked around in this file:
             <option name="radv_override_uniform_offset_alignment" value="16" />
             <option name="radv_disable_shrink_image_store" value="true" />
             <option name="radv_invariant_geom" value="true" />
+            <option name="dual_color_blend_by_location" value="true" />
         </application>
 
         <application name="DOOM VFR" application_name_match="DOOM_VFR">