[Bug ipa/60243] IPA is slow on large cgraph tree

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60243

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |hubicka at gcc dot gnu.org

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
estimate_calls_size_and_time is quite high on the profile - called via
do_estimate_edge_size it walks callgraph edges O(n^2).  It seems that
the idea of having a cache is worse than devising an algorithm to
compute sizes and times for the whole cgraph at once?

The next high thing on the profile is ipa_propagate_frequency_1 called
from do_estimate_growth (same thing, walks over all call edges again).

The ipa-profile slowness is the same - ipa_propagate_frequency.

The testcase has N cgraph nodes and N^2/2 call edges, so it's quite unusual
of course.