[aarch64-port-dev ] RFR: 8172881: AArch64: assertion failure: the int pressure is incorrect

[Andrew Haley]

On 23/01/17 10:41, Ningsheng Jian wrote:
> On 23 January 2017 at 18:13, Andrew Haley <aph at redhat.com> wrote:
>> On 23/01/17 09:02, Ningsheng Jian wrote:
>>
>> I think it would be safest at this stage to change both arguments to
>> iRegLNoSp.  Please try that.  It doesn't make any sense for either
>> argument to be in a special-purpose register.
> 
> The newv is not a def. I think the node which defines it should have
> already taken care of it.

True.  I looked at the code, and I get it now.  It's all rather
confusing: I've just had a look at the way atomic_xchg is defined, and
I see that it uses rscratch2 if prev and newv are allocated the same
register.  It's all rather ugly, but it's OK.

> But yes, both regs should be non-special
> registers. I agree it would be safer to mark them both as non special
> purpose registers.

I don't think it matters.  I'm happy to go with your original patch
if you prefer.

Andrew.