diff --git a/src/compiler/nir/nir_passthrough_gs.c b/src/compiler/nir/nir_passthrough_gs.c
index 6c0fea95e50..0386d1e5223 100644
--- a/src/compiler/nir/nir_passthrough_gs.c
+++ b/src/compiler/nir/nir_passthrough_gs.c
@@ -22,6 +22,7 @@
  */
 
 #include "util/u_memory.h"
+#include "util/u_prim.h"
 #include "nir.h"
 #include "nir_builder.h"
 #include "nir_xfb_info.h"
@@ -134,7 +135,7 @@ nir_create_passthrough_gs(const nir_shader_compiler_options *options,
    nir_shader *nir = b.shader;
    nir->info.gs.input_primitive = gs_in_prim_for_topology(primitive_type);
    nir->info.gs.output_primitive = (force_line_strip_out || emulate_edgeflags) ? MESA_PRIM_LINE_STRIP : original_our_prim;
-   nir->info.gs.vertices_in = vertices_out;
+   nir->info.gs.vertices_in = u_vertices_per_prim(primitive_type);
    nir->info.gs.vertices_out = needs_closing ? vertices_out + 1 : vertices_out;
    nir->info.gs.invocations = 1;
    nir->info.gs.active_stream_mask = 1;