https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94684
Bug ID: 94684
Summary: OpenACC 'async' clause optimizations
Product: gcc
Version: unknown
Status: UNCONFIRMED
Keywords: openacc
Severity: enhancement
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: tschwinge at gcc dot gnu.org
Target Milestone: ---
In 'gcc/omp-expand.c:expand_omp_target', we have an optimization that for an
OpenACC 'async' clause, we try to "pack the async arg in to the tag's operand"
('i_async' handling).
(... which doesn't seem to have any dedicated testsuite coverage.)
That currently only works for 'INTEGER_CST' literals, but not for 'const int
async = 1', for example. Could it, or is 'expand_omp_target' too early for
such things?
Due to only accepting positive values, this doesn't work for the very common
case of 'async' clause without argument, that is: 'async(acc_async_noval)',
that is: 'async(-1)'.
And, couldn't we also optimize the (unusual) case of 'async(acc_async_sync)',
that is: 'async(-2)' by removing the 'async' clause altogether?
