OpenACC middle end changes

[Cesar Philippidis]

I'll try to respond to the reduction stuff. It's been a while since I
started working on it, so I may have lost some state.

On 11/13/2014 10:09 AM, Jakub Jelinek wrote:

>> @@ -233,6 +242,90 @@ static tree scan_omp_1_op (tree *, int *, void *);
>>        *handled_ops_p = false; \
>>        break;
>>  
>> +/* Helper function to get the reduction array name */
>> +static const char *
>> +omp_get_id (tree node)
> 
> Be more specific in the function name what it is for?

It's the name of the array containing the partial reductions for
original reduction variable.

>> +{
>> +  const char *id = IDENTIFIER_POINTER (DECL_NAME (node));
>> +  int len = strlen ("omp$") + strlen (id);
>> +  char *temp_name = (char *)alloca (len+1);
>> +  snprintf (temp_name, len+1, "gfc$%s", id);
> 
> gfc$ ?

It's just a semi-random prefix I used to make the partial reduction
array identifier unique to aid with debugging. I was working on the
fortran front end at the time. Maybe s/gfc/oacc/?

> Use
>   char *temp_name = XALLOCAVEC (char, len + 1);
> instead?
> 
>> +  return IDENTIFIER_POINTER(get_identifier (temp_name));
> 
> Formatting (missing space before ( ).
> 
>> @@ -868,6 +981,25 @@ maybe_lookup_field (tree var, omp_context *ctx)
>>    return n ? (tree) n->value : NULL_TREE;
>>  }
>>  
>> +static inline tree
>> +lookup_reduction (const char *id, omp_context *ctx)
> 
> Can't you use oacc_ in the name of OpenACC specific functions?

Sure.

[snip]

>> @@ -8834,6 +9492,397 @@ make_pass_expand_omp (gcc::context *ctxt)
>>
>>  /* Routines to lower OpenMP directives into OMP-GIMPLE.  */
>>  
>> +/* Helper function to preform, potentially COMPLEX_TYPE, operation and
>> +   convert it to gimple.  */
>> +static void
>> +omp_gimple_assign_with_ops (tree_code op, tree dest, tree src, gimple_seq *seq)
> 
> Makes me wonder why don't you put the reduction code earlier into reduction
> clause GENERIC and then lower into clauses' GIMPLE seq.
> If there is some reason, please name it oacc at least.

I probably was trying to reuse as much of the existing code as possible.
I've swapped out too much state on this. This can be renamed too.

>> +static void
>> +initialize_reduction_data (tree clauses, tree nthreads, gimple_seq *stmt_seqp,
>> +			   omp_context *ctx)
> 
> Likewise.
> 
>> +/* Helper function to process the array of partial reductions.  Nthreads
>> +   indicates the number of threads.  Unfortunately, GOACC_GET_NUM_THREADS
>> +   cannot be used here, because nthreads on the host may be different than
>> +   on the accelerator. */
>> +
>> +static void
>> +finalize_reduction_data (tree clauses, tree nthreads, gimple_seq *stmt_seqp,
>> +			 omp_context *ctx)
> 
> Likewise.
> 
>> +/* Scan through all of the gimple stmts searching for an OMP_FOR_EXPR, and
>> +   scan that for reductions.  */
>> +
>> +static void
>> +process_reduction_data (gimple_seq *body, gimple_seq *in_stmt_seqp,
>> +			gimple_seq *out_stmt_seqp, omp_context *ctx)
> 
> Likewise.

Thomas, would you like me to handle the renaming, or will you? I could
make those changes to gomp-4_0-branch if you like.

Cesar