PR debug/49676
	* dwarf2out.c (int_shift_loc_descriptor): New function.
	(int_loc_descriptor): If shorter, emit i as
	(i >> shift), shift, DW_OP_shl for suitable shift value.
	Similarly, try to optimize large negative values using
	DW_OP_neg of a positive value if shorter.
	(size_of_int_shift_loc_descriptor): New function.
	(size_of_int_loc_descriptor): Adjust to match int_loc_descriptor
	changes.
	(mem_loc_descriptor) <case CONST_INT>: Emit zero-extended constants
	that fit into DWARF2_ADDR_SIZE bytes as int_loc_descriptor +
	DW_OP_GNU_convert instead of DW_OP_GNU_const_type if the former
	is shorter.
	(resolve_addr_in_expr): Optimize DW_OP_plus_uconst with a large
	addend as added DW_OP_plus if it is shorter.

	* gcc.dg/guality/csttest.c: New test.

From-SVN: r176167