[tree-ssa] performance regression after yesterdays mainline merge

[Richard Guenther]

Hi!

The automatic tester at
http://www.tat.physik.uni-tuebingen.de/~rguenth/gcc/monitor-summary.html

caught a performance regression of the compiled tramp3d-v3 code. It's a
7.43s to 7.64s (per iteration) aka 3% regression.

As this is between a mainline merge I suspect something from there causing
this regression (I don't monitor mainline, maybe I should).  Usually
regressins in this test are caused by FP loop pessimizations (as nearly
all time is spent there), and as this is ia64 I suspected

2004-03-29  Fariborz Jahanian <fjahanian@apple.com>

        * fold-const.c (fold): Reassociate multiply expression
        with an adjacent non-multiply expression to use
        architecture's multiply-add instruction.

to be the cause of the regression, but just reverting the above patch
causes another regression to 7.69s - so I'm lost.  Diffs of assembly are
not helpful, as all non-label differences seem to be complete different
compiled routines.

But you may notice the raise in bootstrap time which might (didnt check)
be caused by a regression in gengtype which consumes quite a lot of
bootstrap time on ia64.

Richard.

--
Richard Guenther <richard dot guenther at uni-tuebingen dot de>
WWW: http://www.tat.physik.uni-tuebingen.de/~rguenth/