gcc/
	PR rtl-optimization/84878
	* ddg.c (add_cross_iteration_register_deps): Use DF_REF_BB to determine
	the basic block.  Assert the use reference is not artificial and that
	it has an associated insn.

gcc/testsuite/
	PR rtl-optimization/84878
	* gcc.target/powerpc/pr84878.c: New test.

From-SVN: r259085