gdb

gdb
	* dwarf2loc.c (read_pieced_value): Exit loop when result is full.
	<DWARF_VALUE_OPTIMIZED_OUT>: New case.
	* dwarf2expr.h (enum dwarf_value_location)
	<DWARF_VALUE_OPTIMIZED_OUT>: New constant.
	* dwarf2expr.c (dwarf_expr_stack_empty_p): New function.
	(add_piece): Handle empty piece.
	(execute_stack_op) <DW_OP_piece>: Handle
	DWARF_VALUE_OPTIMIZED_OUT.
gdb/testsuite
	* gdb.dwarf2/pieces.exp (pieces_test_f6): New proc.
	Call it.
	* gdb.dwarf2/pieces.c (struct C): New.
	(f6): New function.
	* gdb.dwarf2/pieces.S: Replace.