Change the arrch64 abi ...(Custom /Specific change)

[Jim Wilson]

On Tue, Apr 5, 2016 at 2:45 AM, Umesh Kalappa <umesh.kalappa0@gmail.com> wrote:
> I need to ,make the  changes only to the  function args(varargs),hence
> making the changes in TARGET_PROMOTE_FUNCTION_MODE will do ?.

If TARGET_PROMOTE_FUNCTION_MODE disagrees with PROMOTE_MODE, it is
possible that the middle end may generate incorrect RTL.  This was
seen with the arm target when it was using different sign extension
for args and locals.  It may or may not be a problem for SImode
extension versus DImode extension.  If you run into optimizer
problems, you may need to change PROMOTE_MODE also to solve them.

> one more question ,i do have defined the TARGET_PROMOTE_FUNCTION_MODE
> (arm.c) and cross compilling for aarch64 ,but still gcc calls
> default_promote_function_node i.e

Add it to aarch64.c instead of arm.c.  arm.c is for 32-bit arm code.
aarch64.c is for 64-bit arm code.

Jim