gcc performance and bootstrap

[Oleg Smolsky <oleg@xxxxxxxxxxxx>]

I've just noticed that gcc5.4 is 3x faster on large/complex files when 
it is built with --enable-bootstrap (as opposed to --disable-bootstrap). 
I thought that the stage2 compiler is already built with itself and so 
there should be no difference between stage2 and stage3 compilers... 
(the host's compiler is gcc 4.8)

Do you know what's going on?

Thanks!
Oleg.