RFR: 8173472: AArch64: C1 comparisons with null only use 32-bit instructions

[Roland Westrelin]

>> I must be missing something. What's wrong with:
>>
>> if (type2aelembytes(opr1->type()) <= 4)
>>
>> ?
> 
> When compressed OOPs are in use, the type in memory is four bytes,
> but we're comparing in registers.

So opr2->type() is T_OBJECT and opr1->type() is T_NARROWOOP?

Roland.