re PR rtl-optimization/44404 (auto-inc-dec generates an invalid assembly instruction)

gcc/
	PR rtl-optimization/44404
	* auto-inc-dec.c (find_inc): Use reg_overlap_mentioned_p instead
	of count_occurrences to see if it's safe to modify mem_insn.insn.
	gcc/testsuite/

gcc/testsuite/
	PR rtl-optimization/44404
	* gcc.dg/pr44404.c: New.

From-SVN: r160374