RFR: 8129426: aarch64: add support for PopCount in C2

Edward Nevill edward.nevill at gmail.com
Mon Jun 22 13:23:21 UTC 2015


Aarch64 currently does not support the PopCountI and PopCountL nodes in aarch64.ad

The following webrev adds support for these using the SIMD instructions 'cnt' and 'addv'


This patch was contributed by alexander.alexeev at caviumnetworks.com

The patch only modifies aarch64 specific files.

I have merged the patch in and tested it with JTreg / hotspot with the following results.

Original: Test results: passed: 847; failed: 13; error: 6
Revised: Test results: passed: 848; failed: 12; error: 6

The single additional failure in the original is the test

FAILED: compiler/intrinsics/squaretolen/TestSquareToLen.java

which is an intermittent failure in the original.

I have benchmarked the patch on four different partner platforms. The average improvement was 2.6X for PopCountI and 2.5X for PopCountL.

Please review and if OK I will push,


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