Dominance information problem

Dominance information problem

[Gary Oblock]

I'm trying to do performance qualification for my structure
reorganization optimization.

I'm doing pretty straightforward stuff and I haven't at this point in
time (qualifying the optimization,) modified the program. So I'm a
little surprised this is failing.  Here is the code that's failing on
the first iteration of the for loops:

  struct cgraph_node *node;
  FOR_EACH_FUNCTION_WITH_GIMPLE_BODY ( node)  {
    struct function *func = DECL_STRUCT_FUNCTION ( node->decl);
    push_cfun ( func);

    class loop *loop;
    FOR_EACH_LOOP_FN ( func, loop, LI_ONLY_INNERMOST )
      {
        size_t num_bbs = loop->num_nodes;
        basic_block *bbs = get_loop_body ( loop); // FAILS HERE!!!
        :
        stuff never reached

How it's failing (in code from dominance.c) I'm guessing tells me the
dominance information is messed up (unlikely) or needs to be
recomputed. If I'm not wrong, how do I go about doing the later????

/* Return TRUE in case BB1 is dominated by BB2.  */
bool
dominated_by_p (enum cdi_direction dir, const_basic_block bb1, const_basic_block bb2)
{
  unsigned int dir_index = dom_convert_dir_to_idx (dir);
  struct et_node *n1 = bb1->dom[dir_index], *n2 = bb2->dom[dir_index];

  gcc_checking_assert (dom_computed[dir_index]); // <=========== BOOM!

  if (dom_computed[dir_index] == DOM_OK)
    return (n1->dfs_num_in >= n2->dfs_num_in
     && n1->dfs_num_out <= n2->dfs_num_out);

  return et_below (n1, n2);
}


Thanks,

Gary Oblock






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Re: Dominance information problem

[Erick Ochoa]

Hi Gary,

I'm not 100% sure this will fix the problem, but in the past I have had 
to call the following function:

   /* If dominator info is not available, we need to calculate it.  */
   if (!dom_info_available_p (CDI_DOMINATORS))
     calculate_dominance_info (CDI_DOMINATORS);

Basically dominance information was not available for cfun.
Also, you might also need to call:

   if (dom_info_available_p (CDI_DOMINATORS))
     free_dominance_info (CDI_DOMINATORS);

Just before your pass is done. These were some calls I needed to make in 
a different pass when I was working with dominators.

On 12/09/2020 09:26, Gary Oblock wrote:
> I'm trying to do performance qualification for my structure
> reorganization optimization.
> 
> I'm doing pretty straightforward stuff and I haven't at this point in
> time (qualifying the optimization,) modified the program. So I'm a
> little surprised this is failing.  Here is the code that's failing on
> the first iteration of the for loops:
> 
>    struct cgraph_node *node;
>    FOR_EACH_FUNCTION_WITH_GIMPLE_BODY ( node)  {
>      struct function *func = DECL_STRUCT_FUNCTION ( node->decl);
>      push_cfun ( func);
> 
>      class loop *loop;
>      FOR_EACH_LOOP_FN ( func, loop, LI_ONLY_INNERMOST )
>        {
>          size_t num_bbs = loop->num_nodes;
>          basic_block *bbs = get_loop_body ( loop); // FAILS HERE!!!
>          :
>          stuff never reached
> 
> How it's failing (in code from dominance.c) I'm guessing tells me the
> dominance information is messed up (unlikely) or needs to be
> recomputed. If I'm not wrong, how do I go about doing the later????
> 
> /* Return TRUE in case BB1 is dominated by BB2.  */
> bool
> dominated_by_p (enum cdi_direction dir, const_basic_block bb1, const_basic_block bb2)
> {
>    unsigned int dir_index = dom_convert_dir_to_idx (dir);
>    struct et_node *n1 = bb1->dom[dir_index], *n2 = bb2->dom[dir_index];
> 
>    gcc_checking_assert (dom_computed[dir_index]); // <=========== BOOM!
> 
>    if (dom_computed[dir_index] == DOM_OK)
>      return (n1->dfs_num_in >= n2->dfs_num_in
>       && n1->dfs_num_out <= n2->dfs_num_out);
> 
>    return et_below (n1, n2);
> }
> 
> 
> Thanks,
> 
> Gary Oblock
> 
> 
> 
> 
> 
> 
> CONFIDENTIALITY NOTICE: This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and contains information that is confidential and proprietary to Ampere Computing or its subsidiaries. It is to be used solely for the purpose of furthering the parties' business relationship. Any unauthorized review, copying, or distribution of this email (or any attachments thereto) is strictly prohibited. If you are not the intended recipient, please contact the sender immediately and permanently delete the original and any copies of this email and any attachments thereto.
> 

Re: Dominance information problem

[Gary Oblock]

Erick,

I assume that this needs to be done on all the functions since
you mention "cfun".

Gary
________________________________
From: Erick Ochoa <erick.ochoa@theobroma-systems.com>
Sent: Monday, September 14, 2020 12:10 AM
To: Gary Oblock <gary@amperecomputing.com>; gcc@gcc.gnu.org <gcc@gcc.gnu.org>
Subject: Re: Dominance information problem

[EXTERNAL EMAIL NOTICE: This email originated from an external sender. Please be mindful of safe email handling and proprietary information protection practices.]


Hi Gary,

I'm not 100% sure this will fix the problem, but in the past I have had
to call the following function:

   /* If dominator info is not available, we need to calculate it.  */
   if (!dom_info_available_p (CDI_DOMINATORS))
     calculate_dominance_info (CDI_DOMINATORS);

Basically dominance information was not available for cfun.
Also, you might also need to call:

   if (dom_info_available_p (CDI_DOMINATORS))
     free_dominance_info (CDI_DOMINATORS);

Just before your pass is done. These were some calls I needed to make in
a different pass when I was working with dominators.

On 12/09/2020 09:26, Gary Oblock wrote:
> I'm trying to do performance qualification for my structure
> reorganization optimization.
>
> I'm doing pretty straightforward stuff and I haven't at this point in
> time (qualifying the optimization,) modified the program. So I'm a
> little surprised this is failing.  Here is the code that's failing on
> the first iteration of the for loops:
>
>    struct cgraph_node *node;
>    FOR_EACH_FUNCTION_WITH_GIMPLE_BODY ( node)  {
>      struct function *func = DECL_STRUCT_FUNCTION ( node->decl);
>      push_cfun ( func);
>
>      class loop *loop;
>      FOR_EACH_LOOP_FN ( func, loop, LI_ONLY_INNERMOST )
>        {
>          size_t num_bbs = loop->num_nodes;
>          basic_block *bbs = get_loop_body ( loop); // FAILS HERE!!!
>          :
>          stuff never reached
>
> How it's failing (in code from dominance.c) I'm guessing tells me the
> dominance information is messed up (unlikely) or needs to be
> recomputed. If I'm not wrong, how do I go about doing the later????
>
> /* Return TRUE in case BB1 is dominated by BB2.  */
> bool
> dominated_by_p (enum cdi_direction dir, const_basic_block bb1, const_basic_block bb2)
> {
>    unsigned int dir_index = dom_convert_dir_to_idx (dir);
>    struct et_node *n1 = bb1->dom[dir_index], *n2 = bb2->dom[dir_index];
>
>    gcc_checking_assert (dom_computed[dir_index]); // <=========== BOOM!
>
>    if (dom_computed[dir_index] == DOM_OK)
>      return (n1->dfs_num_in >= n2->dfs_num_in
>       && n1->dfs_num_out <= n2->dfs_num_out);
>
>    return et_below (n1, n2);
> }
>
>
> Thanks,
>
> Gary Oblock
>
>
>
>
>
>
> CONFIDENTIALITY NOTICE: This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and contains information that is confidential and proprietary to Ampere Computing or its subsidiaries. It is to be used solely for the purpose of furthering the parties' business relationship. Any unauthorized review, copying, or distribution of this email (or any attachments thereto) is strictly prohibited. If you are not the intended recipient, please contact the sender immediately and permanently delete the original and any copies of this email and any attachments thereto.
>