diff --git a/libs/vkd3d-shader/ir.c b/libs/vkd3d-shader/ir.c
index d542fbb0..9eefb82c 100644
--- a/libs/vkd3d-shader/ir.c
+++ b/libs/vkd3d-shader/ir.c
@@ -715,8 +715,7 @@ static bool shader_signature_merge(struct shader_signature *s, uint8_t range_map
         }
     }
     element_count = new_count;
-    /* Signature 's' is a copy of the original signature struct, so we can replace
-     * the 'elements' pointer without freeing it. */
+    vkd3d_free(s->elements);
     s->elements = elements;
     s->element_count = element_count;
 
diff --git a/libs/vkd3d-shader/spirv.c b/libs/vkd3d-shader/spirv.c
index a6700e66..080b2204 100644
--- a/libs/vkd3d-shader/spirv.c
+++ b/libs/vkd3d-shader/spirv.c
@@ -2324,11 +2324,15 @@ static void spirv_compiler_destroy(struct spirv_compiler *compiler)
 
     vkd3d_string_buffer_cache_cleanup(&compiler->string_buffers);
 
+    shader_signature_cleanup(&compiler->input_signature);
+    shader_signature_cleanup(&compiler->output_signature);
+    shader_signature_cleanup(&compiler->patch_constant_signature);
+
     vkd3d_free(compiler);
 }
 
 static struct spirv_compiler *spirv_compiler_create(const struct vkd3d_shader_version *shader_version,
-        const struct vkd3d_shader_desc *shader_desc, const struct vkd3d_shader_compile_info *compile_info,
+        struct vkd3d_shader_desc *shader_desc, const struct vkd3d_shader_compile_info *compile_info,
         const struct vkd3d_shader_scan_descriptor_info *scan_descriptor_info,
         struct vkd3d_shader_message_context *message_context, const struct vkd3d_shader_location *location)
 {
@@ -2428,6 +2432,9 @@ static struct spirv_compiler *spirv_compiler_create(const struct vkd3d_shader_ve
     compiler->input_signature = shader_desc->input_signature;
     compiler->output_signature = shader_desc->output_signature;
     compiler->patch_constant_signature = shader_desc->patch_constant_signature;
+    memset(&shader_desc->input_signature, 0, sizeof(shader_desc->input_signature));
+    memset(&shader_desc->output_signature, 0, sizeof(shader_desc->output_signature));
+    memset(&shader_desc->patch_constant_signature, 0, sizeof(shader_desc->patch_constant_signature));
 
     if ((shader_interface = vkd3d_find_struct(compile_info->next, INTERFACE_INFO)))
     {
@@ -9451,7 +9458,7 @@ static int spirv_compiler_generate_spirv(struct spirv_compiler *compiler,
             && (result = instruction_array_flatten_hull_shader_phases(&instructions)) >= 0)
     {
         result = instruction_array_normalise_hull_shader_control_point_io(&instructions,
-                &parser->shader_desc.input_signature);
+                &compiler->input_signature);
     }
     if (result >= 0)
         result = instruction_array_normalise_io_registers(&instructions, parser->shader_version.type,