re PR tree-optimization/69196 (code size regression with jump threading at -O2)

re PR tree-optimization/69196 (code size regression with jump threading at -O2)

	PR tree-optimization/69196
	* tree-ssa-threadbackward.c (fsm_find_control_statement_thread_paths):
	Do count some PHIs in the thread path against the insn count.  Decrease
	final statement count by one as the control statement in the last
	block will get removed.  Remove special cased code for handling PHIs		in the last block.

	PR tree-optimization/69196
	* gcc.dg/tree-ssa/vrp46.c: Twiddle threading params to keep it from
	duplicating code and spoiling the expected output.

From-SVN: r233866