RFR: 8370438: Offer link time optimization support on library level [v10]

[Matthias Baesken]

On Fri, 21 Nov 2025 06:15:09 GMT, Julian Waters <jwaters at openjdk.org> wrote:

>> Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Add lto to EXTRA_FLAGS, not to OPT
>
> make/autoconf/flags-cflags.m4 line 327:
> 
>> 325:     C_O_FLAG_NONE="-Od"
>> 326:     C_O_FLAG_SIZE="-O1"
>> 327:     C_O_FLAG_LTO="-GL"
> 
> There is sometimes warning spam during linking if -Gy is not set alongside -GL last I remember. This probably won't break LTO builds, but it could possibly be annoying. Whether you want to add the flag is up to you, however.

We build with VS2022 and I cannot see issues/spam .  What would it look like?
Is it something we only see with older VS versions ?

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PR Review Comment: https://git.openjdk.org/jdk/pull/27976#discussion_r2549614850