Avoid a crash in DepthRangeConverter if there are no stages

diff --git a/source/glsl/finalize.cpp b/source/glsl/finalize.cpp
index 9d309785f52774bddd6415a4c6a064df2fa15401..2b7774c5d17e87035e161c1ba4b12af350a8587c 100644 (file)
--- a/source/glsl/finalize.cpp
+++ b/source/glsl/finalize.cpp
@@ -275,8 +275,11 @@ void DepthRangeConverter::apply(Module &module, const Features &features)
        if(features.target_api==VULKAN)
                return;
 
-       for(Stage *s=&module.stages.back(); (!r_position_z_assigned && s); s=s->previous)
-               s->content.visit(*this);
+       if(!module.stages.empty())
+       {
+               for(Stage *s=&module.stages.back(); (!r_position_z_assigned && s); s=s->previous)
+                       s->content.visit(*this);
+       }
 }
 
 unique_ptr<Statement> DepthRangeConverter::create_conversion_statement()