compare-elim.c: Include emit-rtl.h.

compare-elim.c: Include emit-rtl.h.

2017-10-14  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
	    Michael Collison <michael.collison@arm.com>

	* compare-elim.c: Include emit-rtl.h.
	(can_merge_compare_into_arith): New function.
	(try_validate_parallel): Likewise.
	(try_merge_compare): Likewise.
	(try_eliminate_compare): Call the above when no previous clobber
	is available.
	(execute_compare_elim_after_reload): Add DF_UD_CHAIN and DF_DU_CHAIN
	dataflow problems.

2017-10-14  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
	    Michael Collison <michael.collison@arm.com>

	* gcc.target/aarch64/cmpelim_mult_uses_1.c: New test.

Co-Authored-By: Michael Collison <michael.collison@arm.com>
From-SVN: r253764