RFR: 8327661: C1: Make RBP allocatable on x64 when PreserveFramePointer is disabled [v2]

[Denghui Dong]

On Mon, 11 Mar 2024 19:19:32 GMT, Dean Long <dlong at openjdk.org> wrote:

>> Denghui Dong has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   fix: rbp should be callee saved
>
> src/hotspot/cpu/x86/c1_Defs_x86.hpp line 47:
> 
>> 45: 
>> 46: #ifdef _LP64
>> 47:   #define UNALLOCATED 3    // rsp, r15, r10
> 
> This affects pd_nof_caller_save_cpu_regs_frame_map below, but RBP is callee-saved, not caller-saved.

Yes. I updated the patch.

I want to confirm, if we treat RBP as caller saved, is there any correctness problem?

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PR Review Comment: https://git.openjdk.org/jdk/pull/18167#discussion_r1522399378