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Re: 3.4 / 3.5 / tree-ssa comparisons
On Sun, 4 Apr 2004, Andrew Pinski wrote:
>
> On Apr 4, 2004, at 09:57, Richard Guenther wrote:
> > Runtime is 7.73s/it compared to 7.64s/it beforer.
> > So it's not helping, but instead pessimizing slightly!?
>
> This does not make sense because I looked into the tree
> dumps for this code and it looked like it would improve
> it and not hurt it. But there is another patch which is
> in the works which should also help but only in combination
> with the patch which you tested.
I tried to do comparisons with leafify enabled, but I don't seem to be
able to switch off the cast pass with -fno-tree-cast? Using the tree-ssa
build from tonight (which has only extra gfortran patch applied) I get
segfaults of the leafified binaries... - so I have only compile time
comparison which is (with tree-cast)
TOTAL : 233.36 4.04 237.42
vs. (without tree-cast)
TOTAL : 253.57 3.94 257.53
so for leafify enabled builds it definitely helps compile time. Main
improvements are for PHI insertion, DOM, DSE and the thing that is most
helped is PRE which dropped from 16s to 10s. Also improvements all over
the place as we seem to emit a lot less code with the patch (stripped size
4324216 vs. 4447272).
Now it is to find out if tree-cast is "fixing" a bug in tree-ssa that used to
miscompile the testcase in the leafify case, or just masking it, or if the
gfortran update caused the miscompilation (unlikely).
=> I like the patch ;)
Richard.
> Also I was still getting cast removals which should make SRA
> do its work, but we would have to run aliasing again and do
> DOM another time after this second aliasing run so the compile
> time will/should go up.
>
> Also I did a compile time comparison with and without this
> cast patch on PR8361, and the patch was a win in compile
> time by 2 seconds out of a run of 40 seconds so an
> improvement of 5%, maybe adding the leafy patch you will
> see that this patch helps more than what you have looked
> at so far.
>
> Thanks,
> Andrew Pinski
>
--
Richard Guenther <richard dot guenther at uni-tuebingen dot de>
WWW: http://www.tat.physik.uni-tuebingen.de/~rguenth/