microsoft/compiler: Handle both input and output clip/cull distances

For clip/cull coming into a GS and being written, this pass was wrong
and would modify variable types incorrectly. Track both inputs and
outputs separately.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20346>

src/microsoft/compiler/dxil_nir.c

@@ -1054,7 +1054,7 @@ dxil_nir_lower_upcast_phis(nir_shader *shader, unsigned min_bit_size)
 }
 
 struct dxil_nir_split_clip_cull_distance_params {
-   nir_variable *new_var;
+   nir_variable *new_var[2];
    nir_shader *shader;
 };
 
@@ -1072,7 +1072,6 @@ dxil_nir_split_clip_cull_distance_instr(nir_builder *b,
                                         void *cb_data)
 {
    struct dxil_nir_split_clip_cull_distance_params *params = cb_data;
-   nir_variable *new_var = params->new_var;
 
    if (instr->type != nir_instr_type_deref)
       return false;
@@ -1085,6 +1084,9 @@ dxil_nir_split_clip_cull_distance_instr(nir_builder *b,
        !var->data.compact)
       return false;
 
+   unsigned new_var_idx = var->data.mode == nir_var_shader_in ? 0 : 1;
+   nir_variable *new_var = params->new_var[new_var_idx];
+
    /* The location should only be inside clip distance, because clip
     * and cull should've been merged by nir_lower_clip_cull_distance_arrays()
     */
@@ -1129,7 +1131,7 @@ dxil_nir_split_clip_cull_distance_instr(nir_builder *b,
       }
       new_var->data.location++;
       new_var->data.location_frac = 0;
-      params->new_var = new_var;
+      params->new_var[new_var_idx] = new_var;
    }
 
    /* Update the type for derefs of the old var */
@@ -1174,7 +1176,7 @@ bool
 dxil_nir_split_clip_cull_distance(nir_shader *shader)
 {
    struct dxil_nir_split_clip_cull_distance_params params = {
-      .new_var = NULL,
+      .new_var = { NULL, NULL },
       .shader = shader,
    };
    nir_shader_instructions_pass(shader,
@@ -1183,7 +1185,7 @@ dxil_nir_split_clip_cull_distance(nir_shader *shader)
                                 nir_metadata_dominance |
                                 nir_metadata_loop_analysis,
                                 &params);
-   return params.new_var != NULL;
+   return params.new_var[0] != NULL || params.new_var[1] != NULL;
 }
 
 static bool