Re: identifing free() in tree-ssa

[Roger Sayle <roger at eyesopen dot com>]

Hi Olga,

On Tue, 2 Jan 2007, Olga Golovanevsky wrote:
> I wonder what is it a correct (and intelligent) way to identify free (p)
> function in tree-ssa.  I have been looking for BUILT_IN_FREE or
> something similar in builtins.def, but did not find it.

I think recognizing "free" as a built-in (without an intrinsic) is the
correct way to go.  In theory, all of the functions listed in
cp/cfns.gperf should be defined via builtins.def, but unfortunately
the compile-time (and memory) overhead of constructing a large number of
builtins at run-time is already noticeable.  Hence, we only define
those that are most useful [even though I'd like to optimize away calls
to qsort where n is a compile-time constant zero or one! :-)]

If anyone has any ideas on how best these builtins can be constructed
statically and/or lazily, conveniently for those front-ends that can
benefit from them, I'd be very interested in suggestions.  Iant's recent
tweak at http://gcc.gnu.org/ml/gcc-patches/2006-12/msg01774.html was a
clever step in the right direction.

Roger
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