(In reply to comment #12)
>  That happens with default ./autogen blah blah
> 
>  As i said earlier if i pass -mtune=native -march=native flags perf is
> normal, very weird and funny thing in the same time :D

Unless you're provided --enable-debug mesa does mess around with the compiler
optimisation/debug options (-O* and -g*). And it never touches -mtune or
-march. Might be that the compiler is going for some different heuristics
before/after the commit causing substantially different code to be generated ?