v3d: Use the early_fragment_tests flag for the shader's disable-EZ field.

Apparently we need disable-EZ flagged, not just "does Z writes".

Fixes
dEQP-GLES31.functional.image_load_store.early_fragment_tests.no_early_fragment_tests_depth_fbo
on 7278, even though it passed in simulation.

Signed-off-by: Eric Anholt <eric@anholt.net>
Fixes: 051a41d3d5 ("v3d: Add support for the early_fragment_tests flag.")

src/broadcom/compiler/nir_to_vir.c

@@ -1142,7 +1142,9 @@ emit_frag_end(struct v3d_compile *c)
 
                 inst->src[vir_get_implicit_uniform_src(inst)] =
                         vir_uniform_ui(c, tlb_specifier | 0xffffff00);
+                c->writes_z = true;
         } else if (c->s->info.fs.uses_discard ||
+                   !c->s->info.fs.early_fragment_tests ||
                    c->fs_key->sample_alpha_to_coverage ||
                    !has_any_tlb_color_write) {
                 /* Emit passthrough Z if it needed to be delayed until shader
@@ -1172,6 +1174,7 @@ emit_frag_end(struct v3d_compile *c)
 
                 inst->src[vir_get_implicit_uniform_src(inst)] =
                         vir_uniform_ui(c, tlb_specifier | 0xffffff00);
+                c->writes_z = true;
         }
 
         /* XXX: Performance improvement: Merge Z write and color writes TLB

src/broadcom/compiler/v3d_compiler.h

@@ -520,6 +520,7 @@ struct v3d_compile {
         uint32_t centroid_flags[BITSET_WORDS(V3D_MAX_FS_INPUTS)];
 
         bool uses_center_w;
+        bool writes_z;
 
         struct v3d_ubo_range *ubo_ranges;
         bool *ubo_range_used;
@@ -717,7 +718,7 @@ struct v3d_fs_prog_data {
         uint32_t centroid_flags[((V3D_MAX_FS_INPUTS - 1) / 24) + 1];
 
         bool writes_z;
-        bool discard;
+        bool disable_ez;
         bool uses_center_w;
 };
 

src/broadcom/compiler/vir.c

@@ -745,21 +745,9 @@ v3d_fs_set_prog_data(struct v3d_compile *c,
                      struct v3d_fs_prog_data *prog_data)
 {
         v3d_set_fs_prog_data_inputs(c, prog_data);
-        prog_data->writes_z = (c->s->info.outputs_written &
-                               (1 << FRAG_RESULT_DEPTH));
-        prog_data->discard = (c->s->info.fs.uses_discard ||
-                              c->fs_key->sample_alpha_to_coverage);
+        prog_data->writes_z = c->writes_z;
+        prog_data->disable_ez = !c->s->info.fs.early_fragment_tests;
         prog_data->uses_center_w = c->uses_center_w;
-
-        /* If the shader has some side effects and hasn't allowed early
-         * fragment tests, disable them.
-         */
-        if (!c->s->info.fs.early_fragment_tests &&
-            (c->s->info.num_images ||
-             c->s->info.num_ssbos ||
-             c->s->info.num_abos)) {
-                prog_data->discard = true;
-        }
 }
 
 static void
@@ -856,6 +844,15 @@ v3d_nir_lower_fs_early(struct v3d_compile *c)
 {
         if (c->fs_key->int_color_rb || c->fs_key->uint_color_rb)
                 v3d_fixup_fs_output_types(c);
+
+        /* If the shader has no non-TLB side effects, we can promote it to
+         * enabling early_fragment_tests even if the user didn't.
+         */
+        if (!(c->s->info.num_images ||
+              c->s->info.num_ssbos ||
+              c->s->info.num_abos)) {
+                c->s->info.fs.early_fragment_tests = true;
+        }
 }
 
 static void

src/gallium/drivers/v3d/v3dx_draw.c

@@ -203,8 +203,13 @@ v3d_emit_gl_shader_state(struct v3d_context *v3d,
                  * shader needs to write the Z value (even just discards).
                  */
                 shader.fragment_shader_does_z_writes =
-                        (v3d->prog.fs->prog_data.fs->writes_z ||
-                         v3d->prog.fs->prog_data.fs->discard);
+                        v3d->prog.fs->prog_data.fs->writes_z;
+                /* Set if the EZ test must be disabled (due to shader side
+                 * effects and the early_z flag not being present in the
+                 * shader).
+                 */
+                shader.turn_off_early_z_test =
+                        v3d->prog.fs->prog_data.fs->disable_ez;
 
                 shader.fragment_shader_uses_real_pixel_centre_w_in_addition_to_centroid_w2 =
                         v3d->prog.fs->prog_data.fs->uses_center_w;