Yep - you evidently didn't read mine as 165 k lines of c++ isn't exactly a small benchmark :)
Anecdotal, but I've seen similar improvements over g++ in my code.
There are many measures of benchmark sizes. One important measure is size of codes that account for 99% of execution time. If your codebase is a million lines but your hotspot is a thousand lines, benchmark result is sensitive to optimization quirks and in some sense benchmark is small.
More on this idea here: http://blog.pyston.org/2014/12/05/python-benchmark-sizes/
Small benchmarks can go either way, but for large codebase (especially C++) inliner is more important than just about anything else. So GCC wins, because it has better inliner.