Add transform_to_exit_first_loop_alt

Add transform_to_exit_first_loop_alt

2015-06-05  Tom de Vries  <tom@codesourcery.com>

	merge from gomp4 branch:
	2015-05-28  Tom de Vries  <tom@codesourcery.com>

	PR tree-optimization/65443
	* tree-parloops.c (replace_imm_uses, replace_uses_in_bb_by)
	(replace_uses_in_bbs_by, transform_to_exit_first_loop_alt)
	(try_transform_to_exit_first_loop_alt): New function.
	(transform_to_exit_first_loop): Use
	try_transform_to_exit_first_loop_alt.

	* gcc.dg/parloops-exit-first-loop-alt-2.c: New test.
	* gcc.dg/parloops-exit-first-loop-alt-3.c: New test.
	* gcc.dg/parloops-exit-first-loop-alt.c: New test.

	* testsuite/libgomp.c/parloops-exit-first-loop-alt-2.c: New test.
	* testsuite/libgomp.c/parloops-exit-first-loop-alt-3.c: New test.
	* testsuite/libgomp.c/parloops-exit-first-loop-alt.c: New test.

From-SVN: r224154