On Fri, 19 Apr 2024 23:56:00 GMT, ExE Boss <d...@openjdk.org> wrote:
>> We can reduce overhead of first use of a switch bootstrap by moving
>> `typePairToName` into `TypePairs` and by explicitly overriding `hashCode`
>> and `equals`. The first change avoids loading and initializing the
>> `TypePairs` class in actual cases, the second remove some excess code
>> generation from happening on first use.
>
> src/java.base/share/classes/java/lang/runtime/SwitchBootstraps.java line 699:
>
>> 697:
>> 698: public boolean equals(Object other) {
>> 699: if (other instanceof TypePairs otherPair) {
>
> To match the behaviour of the `equals` method body generated by
> `java.lang.runtime.ObjectMethods::bootstrap`, this should include a fast
> path check for `this == other`:
> Suggestion:
>
> if (this == other) {
> return true;
> }
> if (other instanceof TypePairs otherPair) {
No, see https://www.youtube.com/watch?v=kuzjX_efuDs; this fast path is faster
for == matching case but significantly slows down all other branches.
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PR Review Comment: https://git.openjdk.org/jdk/pull/18865#discussion_r1573146432
