PR tree-optimization/93683 - ICE on calloc with unused return value in ao_ref_init_from_ptr_and_size

gcc/testsuite/ChangeLog:

	PR tree-optimization/93683
	* gcc.dg/tree-ssa/ssa-dse-39.c: New test.

gcc/ChangeLog:

	PR tree-optimization/93683
	* tree-ssa-alias.c (stmt_kills_ref_p): Avoid using LHS when not set.