Add TARGET_ADDR_SPACE_ZERO_ADDRESS_VALID
* gimple.c (check_loadstore): Return false when 0 is a valid address.
* fold-const.c (const_unop) [ADDR_SPACE_CONVERT_EXPR]: Do not fold
null when 0 is valid in the source address space.
* target.def (TARGET_ADDR_SPACE_ZERO_ADDRESS_VALID): New.
* targhooks.c (default_addr_space_zero_address_valid): New.
* targhooks.h (default_addr_space_zero_address_valid): Declare.
* doc/tm.texi.in (TARGET_ADDR_SPACE_ZERO_ADDRESS_VALID): Mark it.
* doc/tm.texi: Rebuild.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@229999
138bc75d-0d04-0410-961f-
82ee72b054a4