We ran the bench++ suite, mentioned as well in
http://gcc.gnu.org/ml/gcc/2005-08/msg00197.html ,
using -O2 and we noticed one more interesting case.
Namely, S000005m runs slower (x4) when compiled with
g++-4.0.1 than when compiled with either g++-2.95.3,
or g++-4.1.0-20050723.
This regression does not occur when -O3 is used.
Apparently, it is related to the existance of a
*dead* cerr, as changing the cerr to printf makes
the regression go away, and the assembly shorter.
Is this a caching effect?
--
Summary: performance regression, possibly related to caching
Product: gcc
Version: 4.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: danalis at cis dot udel dot edu
CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: i686-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23322
