On Thu, 30 Oct 2025 13:22:12 GMT, Erik Joelsson <[email protected]> wrote:
> > However it might not work for all versions of these compilers.
>
> When introducing new compiler flags, you need to do one of:
>
> 1. Verify that the flags are supported on all versions of the compiler we
> support. There is a minimum version defined for each. Reading the
> documentation to find out when the compiler feature was introduced is enough,
> you don't need to actually test every version yourself.
> 2. If 1 couldn't be proved, then only add the flag conditionally with a check
> in configure.
The compiler flags are not really 'new' but borrowed from Hotspot LTO.
`MSVC ( -GL -LTCG:INCREMENTAL ): ` available for a long time (~20 years), all
our supported compilers
`AIX :` we only support XLC 14.X, there it is available
`gcc :` -flto=auto -fuse-linker-plugin -fno-strict-aliasing
-fno-fat-lto-objects
since 4.8 (-flto=auto is documented since gcc-10 but older compilers
seem to understand it too)
`clang:` I can find -flto in the clang13 manual
(https://releases.llvm.org/13.0.0/tools/clang/docs/UsersManual.html) but cannot
find -flto=auto , so maybe we should just just -flto in the link flags for
clang ?
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PR Comment: https://git.openjdk.org/jdk/pull/27976#issuecomment-3468699988
