[Bug c++/13776] [tree-ssa] Many C++ compile-time regression in 3.5-tree-ssa 040120

["rguenth at tat dot physik dot uni-tuebingen dot de" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From rguenth at tat dot physik dot uni-tuebingen dot de  2004-03-31 20:01 -------
Subject: Re:  [tree-ssa] Many C++ compile-time regression in
 3.5-tree-ssa 040120

zack at codesourcery dot com wrote:
> ------- Additional Comments From zack at codesourcery dot com  2004-03-31 19:53 -------
> Subject: Re:  [tree-ssa] Many C++ compile-time regression in
>  3.5-tree-ssa 040120
> 
> "rguenth at tat dot physik dot uni-tuebingen dot de" <gcc-bugzilla@gcc.gnu.org> writes:
> 
> 
>>We have a lot of pointer hashing in gcc now and I see the above, too. 
>>We can possibly micro-optimize the pointer hashing by introducing a 
>>"specialization" of the libiberty hashfn for pointers where we can 
>>inline both the hashing function and the comparison function.  It will 
>>introduce some code duplication, though (if this only was using C++ and 
>>templates...).
> 
> 
> Something I've wanted to do for a long time is do poor-man's templates
> on hashtab.[ch] with macros.  But I never seem to get sufficient round
> tuits.

I think it would pay for pointer hashing only, as this is the main use. 
  I did some experiments some time ago with a stripped down pointer-only 
hash just replacing the walk_tree hashtab and it still was #1 in the 
profile with little change in time (but I didn't measure overall 
performance change).

Richard.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13776