RFR: 8332603: [PPC64] Improve itable_stub [v2]

[Martin Doerr]

On Sat, 15 Jun 2024 14:37:37 GMT, Amit Kumar <amitkumar at openjdk.org> wrote:

>> PPC Port similar to [JDK-8305959 (x86)](https://bugs.openjdk.org/browse/JDK-8305959) and [JDK-8307352(aarch64)](https://bugs.openjdk.org/browse/JDK-8307352)
>
> Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:
> 
>   consistency

I'll take a closer look when I find more time.
@varada1110: Do you still have the hs_err file for the error you reported? It would be helpful to see which instruction is getting the value which is too large.
Note that we have `add_const_optmized` available on PPC64 for large offsets if it's an addi instruction.

src/hotspot/cpu/ppc/macroAssembler_ppc.cpp line 1976:

> 1974:   bne(CCR0, L_loop_search_resolved);
> 1975: 
> 1976:   mr_if_needed(holder_offset, scan_temp);

I prefer using `mr` without "_if_needed" after you asserted that the registers are different.

src/hotspot/cpu/ppc/macroAssembler_ppc.cpp line 1983:

> 1981:   cmpdi(CCR0, holder_offset, 0);
> 1982:   beq(CCR0, L_search_holder);
> 1983:   mr_if_needed(scan_temp, holder_offset);

Same, here.

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PR Review: https://git.openjdk.org/jdk/pull/19733#pullrequestreview-2123057335
PR Review Comment: https://git.openjdk.org/jdk/pull/19733#discussion_r1642902552
PR Review Comment: https://git.openjdk.org/jdk/pull/19733#discussion_r1642902887