nir/spirv: Fix handling of gl_PrimitiveId

Before, we were always treating it as an output which bogus.  The only
stage in which this it can be an output is the geometry stage.  In all
other stages, it's an input which, in the back-end, we actually want to be
a system value.

Cc: "13.0" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Dave Airlie <airlied@redhat.com>

diff --git a/src/compiler/spirv/vtn_variables.c b/src/compiler/spirv/vtn_variables.c
index bbcca14..c064de8 100644 (file)
--- a/src/compiler/spirv/vtn_variables.c
+++ b/src/compiler/spirv/vtn_variables.c
@@ -806,8 +806,12 @@ vtn_get_builtin_location(struct vtn_builder *b,
       set_mode_system_value(mode);
       break;
    case SpvBuiltInPrimitiveId:
-      *location = VARYING_SLOT_PRIMITIVE_ID;
-      *mode = nir_var_shader_out;
+      if (*mode == nir_var_shader_out) {
+         *location = VARYING_SLOT_PRIMITIVE_ID;
+      } else {
+         *location = SYSTEM_VALUE_PRIMITIVE_ID;
+         set_mode_system_value(mode);
+      }
       break;
    case SpvBuiltInInvocationId:
       *location = SYSTEM_VALUE_INVOCATION_ID;