On 15-11-14 18:19, Tom de Vries wrote:
> On 15-11-14 13:14, Tom de Vries wrote:
>> Hi,
>>
>> I'm submitting a patch series with initial support for the oacc kernels
>> directive.
>>
>> The patch series uses pass_parallelize_loops to implement parallelization of
>> loops in the oacc kernels region.
>>
>> The patch series consists of these 8 patches:
>> ...
>>      1  Expand oacc kernels after pass_build_ealias
>>      2  Add pass_oacc_kernels
>>      3  Add pass_ch_oacc_kernels to pass_oacc_kernels
>>      4  Add pass_tree_loop_{init,done} to pass_oacc_kernels
>>      5  Add pass_loop_im to pass_oacc_kernels
>>      6  Add pass_ccp to pass_oacc_kernels
>>      7  Add pass_parloops_oacc_kernels to pass_oacc_kernels
>>      8  Do simple omp lowering for no address taken var
>> ...
>
> This patch moves omp expansion of the oacc kernels directive to after
> pass_build_ealias.
>
> The rationale is that in order to use pass_parallelize_loops for analysis and
> transformation of an oacc kernels region, we postpone omp expansion of that
> region until the earliest point in the pass list where enough information is
> availabe to run pass_parallelize_loops, in other words, after pass_build_ealias.
>
> The patch postpones expansion in expand_omp, and ensures expansion by adding
> pass_expand_omp_ssa:
> - after pass_build_ealias, and
> - after pass_all_early_optimizations for the case we're not optimizing.
>
> In order to make sure the oacc kernels region arrives at pass_expand_omp_ssa,
> the way it left expand_omp, the patch makes pass_ccp and pass_forwprop aware of
> lowered omp code, to handle it conservatively.
>
> The patch contains changes in expand_omp_target to deal with ssa-code, similar
> to what is already present in expand_omp_taskreg.
>
> Furthermore, the patch forces the .omp_data_sizes and .omp_data_kinds to not be
> static for oacc kernels. It does this to get some references to .omp_data_sizes
> and .omp_data_kinds in the ssa code.  Without these references, the definitions
> will be removed. The reference of the variables in GIMPLE_OACC_KERNELS is not
> enough to have them not removed. [ In vries/oacc-kernels, I used a BUILT_IN_USE
> kludge for this purpose ].
>
> Finally, at the end of pass_expand_omp_ssa we're left with SSA_NAMEs in the
> original function of which the definition has been removed (as in moved to the
> split off function). TODO_remove_unused_locals takes care of some of them, but
> not the anonymous ones. So the patch iterates over all SSA_NAMEs to find these
> dangling SSA_NAMEs and releases them.
>

Reposting with small update: I've replaced the use of the rather generic 
gimple_stmt_omp_lowering_p with the more specific gimple_stmt_omp_data_i_init_p.

Bootstrapped and reg-tested in the same way as before.

> OK for trunk?
>
> Thanks,
> - Tom