RFR: 8340241: RISC-V: Returns mispredicted [v8]

[Robbin Ehn]

On Mon, 14 Oct 2024 13:16:07 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> Robbin Ehn 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 eight additional commits since the last revision:
>> 
>>  - Merge branch 'master' into remove_t0
>>  - Another one removing explicit use of default t1
>>  - Updated assert
>>  - Updated asserts
>>  - Use x9, comment update
>>  - No need for explicit use of default t1
>>  - Fixed return should be done with RA by using RET mnemonic
>>  - Draft
>
> src/hotspot/cpu/riscv/sharedRuntime_riscv.cpp line 1475:
> 
>> 1473:     Label L_skip_barrier;
>> 1474:     __ mov_metadata(t0, method->method_holder()); // InstanceKlass*
>> 1475:     __ clinit_barrier(t0, t1, &L_skip_barrier);
> 
> What is this change for?

Some clinit_barrier used "t0, t1" and some "t1,t0" I was just annoyed that they were different.

> src/hotspot/cpu/riscv/templateTable_riscv.cpp line 3675:
> 
>> 3673:   __ push_reg(x13);
>> 3674:   // object is at TOS
>> 3675:   __ j(Interpreter::_throw_ClassCastException_entry, t1);
> 
> Use default param.

Not sure why my language server didn't show me this one... fixing

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PR Review Comment: https://git.openjdk.org/jdk/pull/21406#discussion_r1799507326
PR Review Comment: https://git.openjdk.org/jdk/pull/21406#discussion_r1799506620