This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: Compilation time has more than doubled on some Polyhedron tests
On 1/15/06, Tobias Schlüter <tobias.schlueter@physik.uni-muenchen.de> wrote:
>
> In looking at compiles times, I missed looking at memory usage:
>
> Dominique Dhumieres wrote:
> > On an AMD, the 20060105 build gives
> >
> > tree SSA rewrite : 0.45 ( 2%) usr 0.02 ( 5%) sys 0.36 ( 2%) wall 35265 kB (27%) ggc
> > tree SSA incremental : 0.71 ( 4%) usr 0.02 ( 5%) sys 0.77 ( 4%) wall 6145 kB ( 5%) ggc
> > tree operand scan : 0.44 ( 2%) usr 0.07 (18%) sys 0.55 ( 3%) wall 17385 kB (13%) ggc
> > expand : 0.39 ( 2%) usr 0.00 ( 0%) sys 0.46 ( 2%) wall 9703 kB ( 8%) ggc
> > TOTAL : 19.26 0.40 19.91 129144 kB
>
> 20060106:
> > tree SSA rewrite : 0.93 ( 3%) usr 0.03 ( 8%) sys 1.08 ( 3%) wall 65009 kB (33%) ggc
> > tree SSA incremental : 1.84 ( 5%) usr 0.02 ( 5%) sys 1.87 ( 5%) wall 13262 kB ( 7%) ggc
> > tree operand scan : 0.88 ( 3%) usr 0.05 (13%) sys 0.97 ( 3%) wall 29929 kB (15%) ggc
> > expand : 0.97 ( 3%) usr 0.01 ( 3%) sys 1.01 ( 3%) wall 13943 kB ( 7%) ggc
> > TOTAL : 33.82 0.38 34.64 194932 kB
>
> An increase by > 50%. Here and before I extracted the numbers from your
> compilations of induct.f90.
>
> It looks like we're generating significantly more trees now, which would of
> course explain the increase in time spent checking.
I guess the fix for PR tree-optimization/22555 could make some difference
if fortran uses a lot of structures with embedded arrays. Basically this
enables decomposing these structures for aliasing purposes and should
generate better code.
I suggest to do a comparison with --disable-checking and if there's a
significant regression, file a PR about it. At least it would be nice to know
what exactly is going on. You can also try -fno-tree-salias and see if
this helps compile time.
Richard.