rmuir commented on a change in pull request #69: URL: https://github.com/apache/lucene/pull/69#discussion_r609222121
########## File path: lucene/core/src/java/org/apache/lucene/codecs/lucene90/PForUtil.java ########## @@ -121,4 +167,146 @@ void skip(DataInput in) throws IOException { in.skipBytes(forUtil.numBytes(bitsPerValue) + (numExceptions << 1)); } } + + /** + * Fill {@code longs} with the final values for the case of all deltas being 1. Note this assumes + * there are no exceptions to apply. + */ + private static void prefixSumOfOnes(long[] longs, long base) { + System.arraycopy(IDENTITY_PLUS_ONE, 0, longs, 0, ForUtil.BLOCK_SIZE); + // This loop gets auto-vectorized + for (int i = 0; i < ForUtil.BLOCK_SIZE; ++i) { + longs[i] += base; + } + } + + /** + * Fill {@code longs} with the final values for the case of all deltas being {@code val}. Note + * this assumes there are no exceptions to apply. + */ + private static void prefixSumOf(long[] longs, long base, long val) { + for (int i = 0; i < ForUtil.BLOCK_SIZE; i++) { + longs[i] = (i + 1) * val + base; Review comment: > I'm seeing this block, which looks an awful lot like vectorized instructions: yes, the first part looks like ReplL_reg "Replicate long (8 byte) scalar to be vector" from hotspot with avx256 (see the x86.ad file in jdk src). -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org