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Re: [graphds.h] Allocate graph from obstack
Il 19/08/2012 18:55, Richard Guenther ha scritto:
>> > Initially I had one obstack per struct graph, which was better than using
>> > XNEW for every edge, but still obstack_init() called from new_graph() was
>> > too frequent.
>> >
>> > So in this iteration of the patch the obstack is static global, initialised
>> > once and never freed. Please advise on whether this is acceptable, and also
>> > where I should initialise the obstack once, and avoid checking if it's NULL
>> > in every use.
>> >
>> > Minor speed gains (couple of ms), tested with pre-C++ conversion snapshot,
>> > I'll retest soon and post update.
> Either an obstack per graph or the ability to specify an obstack for allocation.
> A global obstack with global lifetime is bad IMHO.
Dimitrios's patch has a per-file obstack with per-pass lifetime, which I
think is the right solution---but putting graph_obstack as a static
variable in graphds.h is uuuugly. You can just move the declaration to
each file separately, and give it a better name perhaps (e.g.
loop_graph_obstack).
Paolo