openacc: Move pass_oacc_device_lower after pass_graphite

openacc: Move pass_oacc_device_lower after pass_graphite

The OpenACC device lowering pass must run after the Graphite pass to
allow for the use of Graphite for automatic parallelization of kernels
regions in the future. Experimentation has shown that it is best,
performancewise, to run pass_oacc_device_lower together with the
related passes pass_oacc_loop_designation and pass_oacc_gimple_workers
early after pass_graphite in pass_tree_loop, at least if the other
tree loop passes are not adjusted. In particular, to enable
vectorization which is crucial for GCN offloading, device lowering
should happen before pass_vectorize. To bring the loops contained in
the offloading functions into the shape expected by the loop
vectorizer, we have to make sure that some passes that previously were
executed only once before pass_tree_loop are also executed on the
offloading functions.  To ensure the execution of
pass_oacc_device_lower if pass_tree_loop does not execute (no loops,
no optimizations), we introduce two further copies of the pass to the
pipeline that run if there are no loops or if no optimization is
performed.

gcc/ChangeLog:

	* omp-general.cc (oacc_get_fn_dim_size): Return 0 on
	missing	"dims".
	* omp-offload.cc (pass_oacc_loop_designation::clone): New
	member function.
	(pass_oacc_gimple_workers::clone): Likewise.
	(pass_oacc_gimple_device_lower::clone): Likewise.
	* passes.cc (pass_data_no_loop_optimizations): New pass_data.
	(class pass_no_loop_optimizations): New pass.
	(make_pass_no_loop_optimizations): New function.
	* passes.def: Move pass_oacc_{loop_designation,
	gimple_workers,	device_lower} into tree_loop, and add
	copies to pass_tree_no_loop and to new
	pass_no_loop_optimizations.  Add copies of passes pass_ccp,
	pass_ipa_warn, pass_complete_unrolli, pass_backprop,
	pass_phiprop, pass_fix_loops after the OpenACC passes
	in pass_tree_loop.
	* tree-ssa-loop-ivcanon.cc (pass_complete_unroll::clone):
	New member function.
	(pass_complete_unrolli::clone): Likewise.
	* tree-ssa-loop.cc (pass_fix_loops::clone): Likewise.
	(pass_tree_loop_init::clone): Likewise.
	(pass_tree_loop_done::clone): Likewise.
	* tree-ssa-phiprop.cc (pass_phiprop::clone): Likewise.

libgomp/ChangeLog:

	* testsuite/libgomp.oacc-c-c++-common/pr85486-2.c: Adjust
	expected output	to pass name changes due to the pass
	reordering and cloning.
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-1.c: Likewise.
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-2.c: Likewise.
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-3.c: Likewise.
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-4.c: Likewise.
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-5.c: Likewise.
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-6.c: Likewise
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-7.c: Likewise.

gcc/testsuite/ChangeLog:

	* gcc.dg/goacc/loop-processing-1.c: Adjust expected output
	to pass name changes due to the pass reordering and cloning.
	* c-c++-common/goacc/classify-kernels-unparallelized.c: Likewise.
	* c-c++-common/goacc/classify-kernels.c: Likewise.
	* c-c++-common/goacc/classify-parallel.c: Likewise.
	* c-c++-common/goacc/classify-routine.c: Likewise.
	* c-c++-common/goacc/routine-nohost-1.c: Likewise.
	* c-c++-common/unroll-1.c: Likewise.
	* c-c++-common/unroll-4.c: Likewise.
	* gcc.dg/goacc/loop-processing-1.c: Likewise.
	* gcc.dg/tree-ssa/backprop-1.c: Likewise.
	* gcc.dg/tree-ssa/backprop-2.c: Likewise.
	* gcc.dg/tree-ssa/backprop-3.c: Likewise.
	* gcc.dg/tree-ssa/backprop-4.c: Likewise.
	* gcc.dg/tree-ssa/backprop-5.c: Likewise.
	* gcc.dg/tree-ssa/backprop-6.c: Likewise.
	* gcc.dg/tree-ssa/cunroll-1.c: Likewise.
	* gcc.dg/tree-ssa/cunroll-3.c: Likewise.
	* gcc.dg/tree-ssa/cunroll-9.c: Likewise.
	* gcc.dg/tree-ssa/ldist-17.c: Likewise.
	* gcc.dg/tree-ssa/loop-38.c: Likewise.
	* gcc.dg/tree-ssa/pr21463.c: Likewise.
	* gcc.dg/tree-ssa/pr45427.c: Likewise.
	* gcc.dg/tree-ssa/pr61743-1.c: Likewise.
	* gcc.dg/unroll-2.c: Likewise.
	* gcc.dg/unroll-3.c: Likewise.
	* gcc.dg/unroll-4.c: Likewise.
	* gcc.dg/unroll-5.c: Likewise.
	* gcc.dg/vect/vect-profile-1.c: Likewise.
	* c-c++-common/goacc/device-lowering-debug-optimization.c: New test.
	* c-c++-common/goacc/device-lowering-no-loops.c: New test.
	* c-c++-common/goacc/device-lowering-no-optimization.c: New test.

Co-Authored-By: Thomas Schwinge <thomas@codesourcery.com>