[nvptx, PR83589] Workaround for branch-around-nothing JIT bug

[nvptx, PR83589] Workaround for branch-around-nothing JIT bug

2018-01-24  Tom de Vries  <tom@codesourcery.com>

	PR target/83589
	* config/nvptx/nvptx.c (WORKAROUND_PTXJIT_BUG_2): Define to 1.
	(nvptx_pc_set, nvptx_condjump_label): New function. Copy from jump.c.
	Add strict parameter.
	(prevent_branch_around_nothing): Insert dummy insn between branch to
	label and label with no ptx insn inbetween.
	* config/nvptx/nvptx.md (define_insn "fake_nop"): New insn.

	* testsuite/libgomp.oacc-c-c++-common/pr83589.c: New test.

From-SVN: r257016