[Bug c/12245] [4.2/4.3/4.4 regression] Uses lots of memory when compiling large initialized arrays

[rguenther at suse dot de]

------- Comment #41 from rguenther at suse dot de  2009-02-21 12:50 -------
Subject: Re:  [4.2/4.3/4.4 regression] Uses lots of memory when
 compiling large initialized arrays

On Sat, 21 Feb 2009, hubicka at gcc dot gnu dot org wrote:

> ------- Comment #40 from hubicka at gcc dot gnu dot org  2009-02-21 12:40 -------
> I happen to have compiler with statistics around:
> We still need about 400MB, mostly integer constants:
> c-decl.c:473 (bind)                                  125040: 0.0%          0:
> 0.0%          0: 0.0%          0: 0.0%       2605
> tree.c:5905 (build_function_type)                     13000: 0.0%          0:
> 0.0%     113400: 0.1%       5056: 0.0%        632
> stringpool.c:73 (alloc_node)                           6032: 0.0%          0:
> 0.0%     174096: 0.1%      13856: 0.0%       1732
> langhooks.c:543 (add_builtin_function_common)             0: 0.0%          0:
> 0.0%     442224: 0.2%      59760: 0.2%       1494
> c-typeck.c:6472 (output_init_element)                     0: 0.0%  
> 47910400:100.0%   45541112:23.7%   26342936:66.6%         19
> convert.c:752 (convert_to_integer)                117415728:44.6%          0:
> 0.0%          0: 0.0%   13046192:33.0%    1630774
> ggc-common.c:187 (ggc_calloc)                      67094608:25.5%          0:
> 0.0%   67162736:34.9%       1088: 0.0%         58
> tree.c:1004 (build_int_cst_wide)                   78264768:29.8%          0:
> 0.0%   78266496:40.7%          0: 0.0%    3261068
> Total                                             262986355         47910416   
>     192171521         39527780          4905807
> source location                                     Garbage            Freed   
>          Leak         Overhead            Times
> 
> 
> It seems that we produce awful amount of garbage during the initializer
> construction.  Perhaps by forcing ggc_collect there we can get down to 200MB
> that we need to reprezent it at the end?

We need the integer csts in the constructor lists.  I have a patch
somewhere (or is it even attached?) that tries to do index compression
and not use the integer csts for counting.  Didn't work out too much
though.

Richard.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12245