[Patch, MIPS] Modify PTR_* macros for mips32r6/mips64r6

[Joseph Myers]

On Fri, 19 Dec 2014, Steve Ellcey  wrote:

> This patch modifies some PTR_* macro definitions for mips32r6 and mips64r6.
> It uses addu/subu instructions for pointer arithmetic as these operations do
> not trap on mips32r6/mips64r6 whereas the add/sub instructions do trap.
> 
> Tested with the mips32r6/mips64r6 GCC, binutils and qemu simulator.
> 
> OK to checkin?

OK.

-- 
Joseph S. Myers
joseph@codesourcery.com