diff --git a/libs/vkd3d-shader/hlsl_codegen.c b/libs/vkd3d-shader/hlsl_codegen.c
index 3b97694a..a2a10fad 100644
--- a/libs/vkd3d-shader/hlsl_codegen.c
+++ b/libs/vkd3d-shader/hlsl_codegen.c
@@ -5309,11 +5309,8 @@ static uint32_t allocate_temp_registers(struct hlsl_ctx *ctx, struct hlsl_ir_fun
     /* ps_1_* outputs are special and go in temp register 0. */
     if (ctx->profile->major_version == 1 && ctx->profile->type == VKD3D_SHADER_TYPE_PIXEL)
     {
-        size_t i;
-
-        for (i = 0; i < entry_func->parameters.count; ++i)
+        LIST_FOR_EACH_ENTRY(var, &entry_func->extern_vars, struct hlsl_ir_var, extern_entry)
         {
-            var = entry_func->parameters.vars[i];
             if (var->is_output_semantic)
             {
                 record_allocation(ctx, &allocator, 0, VKD3DSP_WRITEMASK_ALL,