[nvptx] Verify dimension limits after applying defaults

[nvptx] Verify dimension limits after applying defaults

There's a problem in oacc_validate_dims that when f.i. the worker dimension
is set using -fopenacc-dim=:32, and the vector_length is set using a
"vector_length (128)" clause, the compiler combines, accepts and emits the
values, while the combination of the two is invalid.

The reason for this is that while oacc_validate_dims validates the dimensions
using targetm.goacc.validate_dims before applying default or minimum values,
it does not do so afterwards.

Work around this in the nvptx port by applying the defaults from
oacc_default_dims at the end of nvptx_goacc_validate_dims_1, as
oacc_validate_dims would do it, and then apply the dimensions limits.

2019-01-12  Tom de Vries  <tdevries@suse.de>

	PR middle-end/88703
	* config/nvptx/nvptx.c (nvptx_goacc_validate_dims_1): Apply defaults
	from oacc_default_dims, as oacc_validate_dims would do it, and apply
	dimensions limits.

From-SVN: r267877