On Tue, 20 Dec 2022 21:11:18 GMT, Claes Redestad <redes...@openjdk.org> wrote:
>>> How far off is this ...? >> >> Back then it looked way too constrained (tight constraints on code shapes). >> But I considered it as a generally applicable optimization. >> >>> ... do you think it'll be able to match the efficiency we see here with a >>> memoized coefficient table etc? >> >> Yes, it is able to build the constant table at runtime when folding >> multiplications of constant coefficients produced during loop unrolling and >> then packing scalars into a constant vector. >> >> Moreover, briefly looking at the code shape, the vectorizer would produce a >> more optimal loop shape (pre-loop would align vector accesses and would use >> 512-bit vectors when available; vector post-loop could help as well). > > Passing the constant node through as an input as suggested by @iwanowww and > @sviswa7 meant we could eliminate most of the `instruct` blocks, removing a > significant chunk of code and a little bit of complexity from the proposed > patch. @cl4es Thanks for passing the constant node through, the code looks much cleaner now. The attached patch should handle the signed bytes/shorts as well. Please take a look. [signed.patch](https://github.com/openjdk/jdk/files/10273480/signed.patch) ------------- PR: https://git.openjdk.org/jdk/pull/10847
