[Bug middle-end/40106] Time increase with inlining for the Polyhedron test air.f90

[rguenther at suse dot de]

------- Comment #3 from rguenther at suse dot de  2009-05-12 14:47 -------
Subject: Re:  Time increase with inlining for the
 Polyhedron test air.f90

On Tue, 12 May 2009, dominiq at lps dot ens dot fr wrote:

> ------- Comment #2 from dominiq at lps dot ens dot fr  2009-05-12 13:23 -------
> > decreasing --param hot-bb-frequency-fraction might help in this case.
> 
> I have tried --param hot-bb-frequency-fraction=1 (which seems the smallest
> possible value, see pr40119), but it did not changed anything.
> 
> What I find very surprising is that the ~15% slow-down appears as soon as one
> call is inlined, but without further slow-down with more inlining (I have
> tested 4 and -fwhole-file inline 28 of them). If the block was misoptimized I
> would expect a slow-down increasing with the number of inlined calls. Could the
> problem be related to cache management instead (L1, since L2 is 4Mb on my
> core2Duo)?

You may be hitting some analysis limits either for maximum loop depth
or similar stuff.  There is no other way to analyze what is the difference
in optimizations produced.

Richard.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40106