On Tue, 21 May 2024 00:16:51 GMT, Chen Liang <li...@openjdk.org> wrote:
>> We can fold the call to `Objects.checkIndex` into the code generated in >> generateTypeSwitchSkeleton instead of doing so by filtering the MH argument. >> This loads 9 less classes (of which 8 generated LFs and Species classes) on >> a minimal test, while being neutral on a throughput sanity test: >> >> >> Name Cnt Base Error Test Error Unit Change >> SwitchSanity.switchSum 15 8,162 ± 0,117 8,152 ± 0,131 ns/op 1,00x (p = >> 0,800 ) >> * = significant >> ``` >> >> A few additional optimizations includes generating the switch method using >> the precise type (to avoid the need for an explicitCast adaptation), and >> moving some seldom used `findStatic` calls to a holder. All in all this >> means a reduction by 33-34M cycles to bootstrap a trivial switch expression >> on my M1. > > src/java.base/share/classes/java/lang/runtime/SwitchBootstraps.java line 630: > >> 628: .withMethodBody("typeSwitch", >> 629: >> MethodTypeDescImpl.ofValidated(ConstantDescs.CD_int, >> 630: >> ClassDesc.ofDescriptor(selectorType.descriptorString()), > > `selectorType` can be primitive, therefore verification errors arise at > `aload` in the generated code. This is why tests fail on GitHub actions. Dang. I had focused on making the `java/lang/runtime` tests pass locally, thinking that'd be sufficient. Luckily bf68b1d had only a minor benefit. Backing it out and tidying up a bit gives me these numbers: Wall clock: 65.0 ms/op .taskclock: 75.0 ms/op .cycles: 255323158 average cycles elapsed .instructions: 626086160 average instructions retired ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/19307#discussion_r1607874407