RFR: 8278947: Support for array constants in constant table [v2]

[Jie Fu]

On Tue, 4 Jan 2022 08:47:52 GMT, Quan Anh Mai <duke at openjdk.java.net> wrote:

>> Hi,
>> 
>> This patch adds support for arrays in compiled code constant tables and uses it for various vector replicate operations on x86.
>> 
>> Test: GHA, linux x64 tier 1-3
>> 
>> Thank you very much.
>
> Quan Anh Mai 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 10 additional commits since the last revision:
> 
>  - Merge branch 'master' into constantVectorUpdate
>  - update copyright
>  - missing type in array_constant
>  - Merge branch 'master' into constantVector
>  - use constant table for remaining types
>  - Merge branch 'master' into constantVector
>  - refactor
>  - replicate using constant
>  - Merge branch 'master' into constantVector
>  - initial commit

src/hotspot/share/opto/constantTable.cpp line 44:

> 42:   switch (type()) {
> 43:   case T_INT:     return (_v._value.i == other._v._value.i);
> 44:   case T_FLOAT:   return jint_cast(_v._value.f) == jint_cast(other._v._value.f);

Why did you add `jint_cast`?

Does it mean the original impl for `T_FLOAD` wouldn't work as expected?

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PR: https://git.openjdk.java.net/jdk/pull/6908