[Darwin, PPC] Fix PR71496 by marking pic base loads as non-copyable.

[Darwin, PPC] Fix PR71496 by marking pic base loads as non-copyable.

The Darwin pic base loads (and reloads for non-local-gotos) are not
validly copied (since the pic base label would be duplicated).  Thus,
mark the pic base {re-}loads as non-copyable.

gcc/

2016-12-11  Iain Sandoe  <iain@codesourcery.com>

	PR rtl-optimization/71496
	* config/rs6000/darwin.md (load_macho_picbase_si): Mark as non-
	copyable.  (load_macho_picbase_di, reload_macho_picbase_si,
	reload_macho_picbase_di): Likewise.

From-SVN: r243532