PR ipa/63909

        * gimple-iterator.h (gsi_start_bb_nondebug): New function.
	* ipa-icf-gimple.c (func_checker::compare_bb): Correct iteration
	replaces loop based on precomputed number of non-debug statements.
	* gcc.dg/ipa/pr63909.c: New test.

From-SVN: r218578