------- Comment #20 from amylaar at gcc dot gnu dot org 2009-01-13 14:00 ------- (In reply to comment #19) > Joern, nobody is forcing you to follow the crowd if you think the crowd is > going in the wrong direction.
I have evidence that the direction is wrong. I added a new option to disable partial-partial pre while keeping the rest of -O3 and -ftree-pre enabled. This got EEMBC bitmnp back to the level of 4.2.1 (unmodified 4.4.0 needs 2.55 times the amout of cycles). fbital00 also improved, although it regained only a little of the performance that it lost since 4.2.1 - cycle count is now down 6% against unmodified gcc 4.4.0 . Overall the disabling of partial-partial is also beneficial for EEMBC; there are a few other benchmarks that improved 5 or 6 percent, and the worst regressions are one and two percent. These are the changes in the geometric means of cycle counts by disabling partial-partial redundancy elimination per EEMBC benchmark suite: automotive: 5.73% improvement consumer: 0.04% improvement networking: 0.37% improvement office: 1.39% worse telecom: 0.00% worse -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38401
