On Mon, 14 Oct 2024 15:04:54 GMT, Jasmine Karthikeyan <jkarthike...@openjdk.org> wrote:
> For the record I think in this PR we could simply match the IR patterns in > the ad file, since (from my understanding) the patterns we are matching could > be supported there. We should do platform-specific lowering in a separate > patch because it is pretty nuanced, and we could potentially move it to the > new system afterwards. Hi @jaskarth , Bigger pattern matching is sensitive to [IR level node sharing](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/opto/matcher.cpp#L1724), thus it may not full proof for above 4 patterns. Current patch takes care of this limitation. > @jatin-bhateja That is machine-independent lowering, we are talking about > machine-dependent lowering to which `MacroLogicV` transformation belongs. You > can have `phaselowering_x86` and not have to add another method to `Matcher` > as well as add default implementations to various architecture files. You can > reuse `MulVL` node for that but I believe these transformations should be > done as late as possible. Hi @merykitty, I see some scope of refactoring and carving out a separate target specific lowering pass going forward, I have brough this up in past too. Existing optimizations are in line with current infrastructure and guards target specific optimizations with target specific match_rule_supported checks e.g. https://github.com/openjdk/jdk/blob/master/src/hotspot/share/opto/compile.cpp#L2898. As @jaskarth suggests we can pick this up going forward. ------------- PR Comment: https://git.openjdk.org/jdk/pull/21244#issuecomment-2411884206
