New runtimize optimization: mix(a,a,x) -> a  (even if none are constant!)
New runtimize optimization: mix(a,a,x) -> a  (even if none are constant!)

svenstaro/OpenShadingLanguage,johnhaddon/OpenShadingLanguage,fpsunflower/OpenShadingLanguage,sjparker/OpenShadingLanguage,lgritz/OpenShadingLanguage,yaroslav-tarasov/OpenShadingLanguage,lgritz/OpenShadingLanguage,brechtvl/OpenShadingLanguage,mcanthony/OpenShadingLanguage,sjparker/OpenShadingLanguage,yaroslav-tarasov/OpenShadingLanguage,aconty/OpenShadingLanguage,mcanthony/OpenShadingLanguage,amartinez-cg/OpenShadingLanguage,svenstaro/OpenShadingLanguage,lgritz/OpenShadingLanguage,imageworks/OpenShadingLanguage,gzorin/OpenShadingLanguage,fpsunflower/OpenShadingLanguage,sjparker/OpenShadingLanguage,lgritz/OpenShadingLanguage,amartinez-cg/OpenShadingLanguage,fpsunflower/OpenShadingLanguage,gzorin/OpenShadingLanguage,svenstaro/OpenShadingLanguage,juvenal/OpenShadingLanguage,brechtvl/OpenShadingLanguage,juvenal/OpenShadingLanguage,mcanthony/OpenShadingLanguage,sjparker/OpenShadingLanguage,gzorin/OpenShadingLanguage,imageworks/OpenShadingLanguage,brechtvl/OpenShadingLanguage,yaroslav-tarasov/OpenShadingLanguage,brechtvl/OpenShadingLanguage,juvenal/OpenShadingLanguage,brechtvl/OpenShadingLanguage,gzorin/OpenShadingLanguage,yaroslav-tarasov/OpenShadingLanguage,mcanthony/OpenShadingLanguage,rlmh/OpenShadingLanguage,imageworks/OpenShadingLanguage,imageworks/OpenShadingLanguage,svenstaro/OpenShadingLanguage,gzorin/OpenShadingLanguage,johnhaddon/OpenShadingLanguage,aconty/OpenShadingLanguage,lgritz/OpenShadingLanguage,amartinez-cg/OpenShadingLanguage,aconty/OpenShadingLanguage,aconty/OpenShadingLanguage,aconty/OpenShadingLanguage,rlmh/OpenShadingLanguage,juvenal/OpenShadingLanguage,johnhaddon/OpenShadingLanguage,rlmh/OpenShadingLanguage,amartinez-cg/OpenShadingLanguage,imageworks/OpenShadingLanguage,fpsunflower/OpenShadingLanguage,rlmh/OpenShadingLanguage,johnhaddon/OpenShadingLanguage,amartinez-cg/OpenShadingLanguage