[llvm] r243308 - [AArch64] Remove check for Darwin that was needed to decide if x18 should

[Justin Bogner via llvm-commits]

Eric Christopher <echristo at gmail.com> writes:
> On Fri, Nov 13, 2015 at 2:26 PM Tim Northover <tnorthover at apple.com> wrote:
>>> I think the right thing to do is to default ReserveX18 in the
>>> AArch64Subtarget constructor based on isOSDarwin. i.e.:
>>
>> I think I agree. The triple ought to be enough to give reasonably
>> ABI-compliant code, otherwise why include the OS there in the first place?
>
> Seems reasonable.

I've done this in r253102.

>>> If we do this we can also revert r243310 since it'll become redundant.
>>> WDYT?
>>
>> Probably a good idea too.
>
> Sure.

and this in r253104.

> I think this will mean that it's not currently possible to turn it off, but
> if we need that we can add a -mno- reserve option to clang.

This is easy to do if someone needs it, but I don't know of anyone that
does so I've left it out for now.