RFR(M): 8154826: AArch64: take better advantage of base + shifted offset addressing mode

Dean Long dean.long at oracle.com
Thu Apr 21 22:09:31 UTC 2016

Hi Roland.  This sounds like it has a lot of overlap with JDK-6217251.  
If so, could you update JDK-6217251 explaining what more, if anything, 
needs to be done?



On 4/21/2016 1:23 AM, Roland Westrelin wrote:
> http://cr.openjdk.java.net/~roland/8154826/webrev.00/
> The aarch64 port implicitly transforms:
> (AddP base (AddP base address (LShiftL index con)) offset)
> into:
> (AddP base (AddP base offset) (LShiftL index con))
> in the ad file to embed the shift (and possibly and i2l conversion) into
> the addressing mode of a memory operation. Exposing that transformation
> in the ideal graph allows:
> - (AddP base offset) to be scheduled (for instance outside a loop)
> - multiple identical (AddP base offset) to be commoned
> - (LShiftL index con) to be cloned during matching so that each memory
> access has its own
> Roland.

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