On Thu, 3 Mar 2022 12:45:51 GMT, Claes Redestad <redes...@openjdk.org> wrote:
>>> * There are a few minor regressions (~5%) in the x86 implementation on >>> `encode-/decodeLatin1Short`. Those regressions disappear when mixing >>> inputs, for example `encode-/decodeShortMixed` even see a minor >>> improvement, which makes me consider those corner case regressions with >>> little real world implications (if you have latin1 Strings, you're likely >>> to also have ASCII-only strings in your mix). >> >> I'm not sure that we can disregard such cases. You're probably right, but >> it'd be interesting to know the actual cause of the problem, perhaps with >> perfasm. Or do you know already? > >> > ``` >> > * There are a few minor regressions (~5%) in the x86 implementation on >> > `encode-/decodeLatin1Short`. Those regressions disappear when mixing >> > inputs, for example `encode-/decodeShortMixed` even see a minor >> > improvement, which makes me consider those corner case regressions with >> > little real world implications (if you have latin1 Strings, you're likely >> > to also have ASCII-only strings in your mix). >> > ``` >> >> I'm not sure that we can disregard such cases. You're probably right, but >> it'd be interesting to know the actual cause of the problem, perhaps with >> perfasm. Or do you know already? > > Still looking into it in detail, but the shape of the code at the bytecode > level is different, so generated code looks quite different, which means the > logical branches can be laid out differently, or just placed in a different > order. The 5% in this particular test could easily be due to getting a > different order of the tests for determining if a byte is ascii or latin1. > > I'm also in the process of measuring in detail after narrowing down the > `bottom_type()` of the intrinsic and a few other recent fixes that could > affect code generation in C2. Will also benchmark on aarch64 and report back. > > @cl4es Looks like you forgot to remove the "@IntrinsicCandidate" annotation > > for has_negatives. > > I was going back and forth ... Well, it just didn't build. With the annotation being present, you also need an intrinsic implementation. That's what the error message is saying... ------------- PR: https://git.openjdk.java.net/jdk/pull/7231
