[PATCH] Allow the frontend to reserve x18 on AArch64

[Tim Northover]

Hi Andrew,

On 20 January 2015 at 09:59, Andrew Turner <andrew at fubar.geek.nz> wrote:
> The attached patch allows the x18 platform register on AArch64 to be
> reserved by users of llvm.

This looks reasonable, modulo one comment on the test:

+; CHECK-RESERVE-X18-NOT: ldr fp
+; CHECK-RESERVE-X18-NOT: ldr x18
+; CHECK-RESERVE-X18: Spill
+; CHECK-RESERVE-X18-NOT: ldr fp
+; CHECK-RESERVE-X18-NOT: ldr x18
+; CHECK-RESERVE-X18: ret

These are identical to the DARWIN checks, aren't they? If so, they
should probably be combined (likely by renaming to CHECK-RESERVE-X18
for both platforms).

Cheers.

Tim.