nir/lower_gs_intrinsics: fix primitive count for points

When primitive is points, EndPrimitive can't be used to count
primitive. Need to use vertex count instead. And it's also not
needed to do vertex per primitive count and overwrite incomplete
primitive work for points.

Fixes: 2be99012e95 ("nir: Add ability to count emitted GS primitives.")
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Signed-off-by: Qiang Yu <yuq825@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17805>
(cherry picked from commit 84956286a8d30790dda7568043ec2b546904fdf2)

2 files changed, 28 insertions, 5 deletions

diff --git a/.pick_status.json b/.pick_status.json
index c8cd90b88d2..35a62c0ca62 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -598,7 +598,7 @@
         "description": "nir/lower_gs_intrinsics: fix primitive count for points",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "2be99012e95bd8b0b17b5c06b31723738aaecbd1"
     },
diff --git a/src/compiler/nir/nir_lower_gs_intrinsics.c b/src/compiler/nir/nir_lower_gs_intrinsics.c
index a9c2ffcf3e9..1d8b6ee6099 100644
--- a/src/compiler/nir/nir_lower_gs_intrinsics.c
+++ b/src/compiler/nir/nir_lower_gs_intrinsics.c
@@ -63,6 +63,7 @@ struct state {
    bool count_prims;
    bool count_vtx_per_prim;
    bool overwrite_incomplete;
+   bool is_points;
    bool progress;
 };
 
@@ -89,6 +90,8 @@ rewrite_emit_vertex(nir_intrinsic_instr *intrin, struct state *state)
 
    if (state->count_vtx_per_prim)
       count_per_primitive = nir_load_var(b, state->vtxcnt_per_prim_vars[stream]);
+   else if (state->is_points)
+      count_per_primitive = nir_imm_int(b, 0);
    else
       count_per_primitive = nir_ssa_undef(b, 1, 32);
 
@@ -208,6 +211,8 @@ rewrite_end_primitive(nir_intrinsic_instr *intrin, struct state *state)
 
    if (state->count_vtx_per_prim)
       count_per_primitive = nir_load_var(b, state->vtxcnt_per_prim_vars[stream]);
+   else if (state->is_points)
+      count_per_primitive = nir_imm_int(b, 0);
    else
       count_per_primitive = nir_ssa_undef(b, count->num_components, count->bit_size);
 
@@ -290,7 +295,7 @@ append_set_vertex_and_primitive_count(nir_block *end_block, struct state *state)
          if (state->per_stream && !(shader->info.gs.active_stream_mask & (1 << stream))) {
             /* Inactive stream: vertex count is 0, primitive count is 0 or undef. */
             vtx_cnt = nir_imm_int(b, 0);
-            prim_cnt = state->count_prims
+            prim_cnt = state->count_prims || state->is_points
                        ? nir_imm_int(b, 0)
                        : nir_ssa_undef(b, 1, 32);
          } else {
@@ -298,9 +303,16 @@ append_set_vertex_and_primitive_count(nir_block *end_block, struct state *state)
                overwrite_incomplete_primitives(state, stream);
 
             vtx_cnt = nir_load_var(b, state->vertex_count_vars[stream]);
-            prim_cnt = state->count_prims
-                       ? nir_load_var(b, state->primitive_count_vars[stream])
-                       : nir_ssa_undef(b, 1, 32);
+
+            if (state->count_prims)
+               prim_cnt = nir_load_var(b, state->primitive_count_vars[stream]);
+            else if (state->is_points)
+               /* EndPrimitive does not affect primitive count for points,
+                * just use vertex count instead
+                */
+               prim_cnt = vtx_cnt;
+            else
+               prim_cnt = nir_ssa_undef(b, 1, 32);
          }
 
          nir_set_vertex_and_primitive_count(b, vtx_cnt, prim_cnt, stream);
@@ -361,12 +373,23 @@ nir_lower_gs_intrinsics(nir_shader *shader, nir_lower_gs_intrinsics_flags option
       overwrite_incomplete ||
       (options & nir_lower_gs_intrinsics_count_vertices_per_primitive);
 
+   bool is_points = shader->info.gs.output_primitive == SHADER_PRIM_POINTS;
+   /* points are always complete primitives with a single vertex, so these are
+    * not needed when primitive is points.
+    */
+   if (is_points) {
+      count_primitives = false;
+      overwrite_incomplete = false;
+      count_vtx_per_prim = false;
+   }
+
    struct state state;
    state.progress = false;
    state.count_prims = count_primitives;
    state.count_vtx_per_prim = count_vtx_per_prim;
    state.overwrite_incomplete = overwrite_incomplete;
    state.per_stream = per_stream;
+   state.is_points = is_points;
 
    nir_function_impl *impl = nir_shader_get_entrypoint(shader);
    assert(impl);