RFR: 8296545: C2 Blackholes should allow load optimizations [v3]

[Aleksey Shipilev]

On Mon, 14 Nov 2022 21:14:38 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:
>> 
>>  - Blackhole as CFG node
>>  - Merge branch 'master' into JDK-8296545-blackhole-effects
>>  - Blackhole should be AliasIdxTop
>>  - Do not touch memory at all
>>  - Fix
>
> src/hotspot/share/opto/cfgnode.hpp line 610:
> 
>> 608: // Blackhole all arguments. This node would survive through the compiler
>> 609: // the effects on its arguments, and would be finally matched to nothing.
>> 610: class BlackholeNode : public MultiNode {
> 
> Also update comment at [cfgnode.hpp#L43](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/opto/cfgnode.hpp#L43)

Done so!

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PR: https://git.openjdk.org/jdk/pull/11041