reassoc: Do not bias loop-carried PHIs early

reassoc: Do not bias loop-carried PHIs early

Biasing loop-carried PHIs during the 1st reassociation pass interferes
with reduction chains and does not bring measurable benefits, so do it
only during the 2nd reassociation pass.

gcc/ChangeLog:

	* passes.def (pass_reassoc): Rename parameter to early_p.
	* tree-ssa-reassoc.c (reassoc_bias_loop_carried_phi_ranks_p):
	New variable.
	(phi_rank): Don't bias loop-carried phi ranks
	before vectorization pass.
	(execute_reassoc): Add bias_loop_carried_phi_ranks_p parameter.
	(pass_reassoc::pass_reassoc): Add bias_loop_carried_phi_ranks_p
	initializer.
	(pass_reassoc::set_param): Set bias_loop_carried_phi_ranks_p
	value.
	(pass_reassoc::execute): Pass bias_loop_carried_phi_ranks_p to
	execute_reassoc.
	(pass_reassoc::bias_loop_carried_phi_ranks_p): New member.