Does Unity optimize GLSL? (FROM Glsl)

So, http://docs.unity3d.com/Manual/SL-GLSLShaderPrograms.html mentions

Unity will cross-compile Cg/HLSL into optimized GLSL

Using: https://github.com/aras-p/glsl-optimizer

However (even though I know it's not recommended), say I wrote my shaders in GLSL in the first place, using GLSLPROGRAM / ENDGLSL would Unity optimize this GLSL, or leave it how it is?

What i'm asking is, is it worth me running my own GLSL through the optimizer, then putting it back into my shaders, or am I just redoing what unity already does?

Looking at the shaders with PerfHUD ES, it doesn't look like it is?