Compile time improvement, runtime regression (ia64)

[Richard Guenther]

Since the last two days I experience a compile time improvement both in 
bootstrap times (50min vs. 60min before - but also switched host 
compiler to 3.4.0 from 3.3.4) and tramp3d-v3 (non-leafified) testcase
(2min30 vs. 3min before).  Unfortunately tramp3d-v3 performance 
regressed from about 7.5s/it to 8s/it.

There's a hole in testing due to various bootstrapping problems on ia64 
in the last week, so the precise cause remains uncertain.

Any ideas what causes the performance drop?

Thanks,
Richard.