[Bug tree-optimization/26854] Inordinate compile times on large routines

["zadeck at naturalbridge dot com" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #45 from zadeck at naturalbridge dot com  2007-12-20 15:31 -------
Subject: Re:  Inordinate compile times on large
 routines

stevenb dot gcc at gmail dot com wrote:
> ------- Comment #44 from stevenb dot gcc at gmail dot com  2007-12-20 15:08 -------
> Subject: Re:  Inordinate compile times on large routines
>
> On 20 Dec 2007 14:49:12 -0000, zadeck at naturalbridge dot com
> <gcc-bugzilla@gcc.gnu.org> wrote:
>   
>> ------- Comment #43 from zadeck at naturalbridge dot com  2007-12-20 14:49 -------
>> Subject: Re:  Inordinate compile times on large
>>  routines
>>
>> lucier at math dot purdue dot edu wrote:
>>     
>>> ------- Comment #42 from lucier at math dot purdue dot edu  2007-12-20 03:52 -------
>>> Created an attachment (id=14799)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14799&action=view)
>>>       
>  --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14799&action=view)
>   
>>  --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14799&action=view)
>>     
>>>  --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14799&action=view)
>>> memory details for an unpatched mainline
>>>
>>> Here is the same information without Steven's two patches for mainline.
>>>
>>>
>>>
>>>       
>> Could you add the attached patch in and rerun your example?
>>
>> It will add 4 lines to indicate what kinds of def-use and use-def chains
>> are being created.
>> A lot of the space is being used by these chains and I want to find out
>> how many of those chains are for artificial uses and defs.
>>
>> thanks
>>
>> kenny
>>  struct df_link *
>>  df_chain_create (struct df_ref *src, struct df_ref *dst)
>>  {
>>    struct df_link *head = DF_REF_CHAIN (src);
>> -  struct df_link *link = pool_alloc (df_chain->block_pool);;
>> +  struct df_link *link = pool_alloc (df_chain->block_pool);
>> +  int index = 0;
>> +
>> +  if (!src->insn)
>> +    index += (src->type == DF_REF_REG_DEF) ? 2 : 1;
>> +  if (!dst->insn)
>> +    index += (src->type == DF_REF_REG_DEF) ? 2 : 1;
>> +
>> +  df_chain_counters[index]++;
>>     
>
> Watch for segfaults. Index will be 1, 2, 3, or 4.
> df_chain_counters[4] does not exist.
>
>
>   
indexes will be 0, 1, 2, 3.

there are no def-def chains, and in particular there are no artificial
def to artificial def chains.  those increments only happen for
artificial defs or uses. Regular uses or defs have an insn.   a normal
def-use chain will have index 0.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26854