[15] RFR (M): 8238690: C2: Handle vector shifts by constant and non-constant scalar uniformly

Viswanathan, Sandhya sandhya.viswanathan at intel.com
Fri Feb 7 18:15:49 UTC 2020


Hi Vladimir,

Your patch looks good to me.

Best Regards,
Sandhya

-----Original Message-----
From: Vladimir Ivanov <vladimir.x.ivanov at oracle.com> 
Sent: Friday, February 07, 2020 6:49 AM
To: hotspot compiler <hotspot-compiler-dev at openjdk.java.net>
Cc: Viswanathan, Sandhya <sandhya.viswanathan at intel.com>; Bhateja, Jatin <jatin.bhateja at intel.com>
Subject: [15] RFR (M): 8238690: C2: Handle vector shifts by constant and non-constant scalar uniformly

http://cr.openjdk.java.net/~vlivanov/8238690/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8238690

Unify IR shape for vector shifts by scalar and always use:
    ShiftV src (ShiftCntV shift)

Right now, constant case has a special representation:
    ShiftV src ConI

It allows to simplify generic vector logic a bit and get rid of auxilliary chain rule on x86 (vshiftcntimm).

Testing: tier1-4

Best regards,
Vladimir Ivanov


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