------- Comment #2 from steven at gcc dot gnu dot org 2010-04-25 12:13 -------
Confirmed on x86_64-linux by comparing gcc 4.3.3 vs. gcc 4.6.0 (r158482). The
average of 10 runs on each is 5.1s with gcc 4.3.3 vs. 5.7s for gcc 4.4.2, gcc
4.5.0 and gcc 4.6.0.
One interesting difference is that GCC 4.5 does not inline fib. But that
shouldn't have a big impact on performance. The generated code for fib is
completely different (maybe an IRA thing??), so it's hard to tell where the
slow-down comes from.
--
steven at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2010-04-25 12:13:24
date| |
Summary|Performance degradation of |[4.4/4.5 Regression]
|the simple example |Performance degradation for
|(fibonacci) 4.3.3->4.5.0 |simple fibonacci numbers
| |calculation
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43884
