compiler: reject incorrect unsafe.Offsetof expressions.

The x.Field argument to Offsetof may not involve hidden
dereferences of embedded pointer fields.

Also correct uninitialized implicit_ field.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@200221 138bc75d-0d04-0410-961f-82ee72b054a4
2013-06-19  Wei Mi  <wmi@google.com>

	PR rtl-optimization/57518
	* ira.c (set_paradoxical_subreg): Set pdx_subregs[regno]
	if regno is used in paradoxical subreg.
	(update_equiv_regs): Check pdx_subregs[regno] before
	set a reg to be equivalent with a mem.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@200224 138bc75d-0d04-0410-961f-82ee72b054a4