RFR: 8073093: AARCH64: C2 generates poor code for ByteBuffer accesses

Christos Zoulas christos at zoulas.com
Fri Feb 13 23:04:16 UTC 2015


On Feb 13,  2:52pm, dean.long at oracle.com (Dean Long) wrote:
-- Subject: Re: RFR: 8073093: AARCH64: C2 generates poor code for ByteBuffer 

| My understanding is that whether or not aarch64 allows unaligned=20
| accesses is based on a
| system setting, so this change is too simplistic.  I would prefer that=20
| this was controlled with
| something more flexible, like "sun.cpu.unaligned".

So does x86_64 and you can ask the CPU if it is enabled... I am not sure
if a variable setting makes sense because if alignment is required you
get a signal (BUS error -- hi linux, SEGV), or incorrect results.

christos



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