On Tue, 26 Nov 2024 18:15:47 GMT, Quan Anh Mai <qa...@openjdk.org> wrote:
>> src/jdk.incubator.vector/share/classes/jdk/incubator/vector/AbstractVector.java >> line 228: >> >>> 226: } >>> 227: >>> 228: AbstractVector<?> iota = vspecies().asIntegral().iota(); >> >> I suspect the non-power of two code is more efficient. (Even better if the >> MUL could be transformed to a shift for power of two values.) >> >> Separately, it makes me wonder if we should revisit the shuffle factories if >> it is now much more efficient to construct a shuffle from a vector. > > `shuffleFromOp` is a slow path op so I don't think it is. Additionally, our > vector multiplication is against a scalar, too. So we can optimize it if > `step` is a constant. I incorrectly read `!=` as `==` :-) as that is the more common pattern used in the code base, so i was thinking the power of two code path was using `shuffleFromOp`. Could you invert the check to be more consistent? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/21042#discussion_r1872048156
