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Re: Trivial speedup to aliasing
- From: Daniel Berlin <dberlin at dberlin dot org>
- To: Jan Hubicka <jh at suse dot cz>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Sun, 11 Jan 2004 20:23:50 -0500
- Subject: Re: Trivial speedup to aliasing
- References: <20040112002125.GQ1964@kam.mff.cuni.cz>
On Jan 11, 2004, at 7:21 PM, Jan Hubicka wrote:
Hi,
about 3% of Gerald's application compile time is consumed by splay
tree walking
that comes from aliasing. It seems to me that it is safe to replace
this by
trivial varray as alias sets are always allocated consetuctively.
With this
patch I can save almost all the overhead and get the lookup off the
profiles.
I also measured 2 seconds out of 2 minutes GCC component compile time
but it
may be noise.
I noticed that varray.c requires GENERIC_PTR to be in GGC memory.
This looks
wrong to me that when we do GGC we need to know the type anyway.
This is what GTY ((param_is ("<typename>"))) is for.
There are VARRAY_GENERIC arrays with ggc'd things in them that need to
be marked, so don't do this.
We added a noggc counterpart on the tree-ssa branch.
Personally, I don't like that generic_ptr is ggc_alloc'd either, but
unless you fix all the GTY'd generic varrays that need to be marked,
you can't do this.