[PATCH] D24661: More processors support under AARch64 state for auto detection.

[Renato Golin via llvm-commits]

On 21 September 2016 at 15:49, James Greenhalgh
<james.greenhalgh at arm.com> wrote:
> The X-Gene-1 machines I have access to do not have the CRC feature (also
> optional as per ARMv8-A specs). I believe X-Gene 2 is the first generation
> of X-Gene processors to support the CRC extension.

Indeed.

I have access to revisions 0 and 1 of X-Gene-1 and none of them have CRC.

Not only the "features" string doesn't show them, but CRC32 traps with SIGILL.


> I would find it surprising if passing -mcpu=xgene1 to Clang enabled
> generation of instructions from the CRC extension, as these would cause a
> SIGILL on my (and as far as I am aware, all) X-Gene 1 machines.

That would be completely wrong, yes.

--renato