guix: disable LTO in GCC #35261

pull fanquake wants to merge 5 commits into bitcoin:master from fanquake:guix_gcc_disable_lto changing 1 files +28 −21

fanquake commented at 3:19 PM on May 11, 2026: member

We don't use LTO in release builds, and neither do any of our dependencies, so disable support in GCC. This reduces what needs to be compiled when building the Guix toolchain. It would also make it clear if something started using it.

Also disable Native Language Support as this is also not needed:

The --enable-nls option enables Native Language Support (NLS), which lets GCC output diagnostics in languages other than American English. Native Language Support is enabled by default if not doing a canadian cross build.

See https://gcc.gnu.org/install/configure.html.
DrahtBot added the label Build system on May 11, 2026
DrahtBot commented at 3:19 PM on May 11, 2026: contributor


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For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35261.



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Conflicts

Reviewers, this pull request conflicts with the following ones:
- #25573 (guix: produce a -static-pie bitcoind by fanquake)
If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.
fanquake marked this as ready for review on May 11, 2026
winterrdog commented at 8:14 PM on May 16, 2026: none

in the PR description:

saves some compilation

i'd like to assume you meant 'saves some compilation time' rather than 'saves some compilation' - is that right ?
fanquake force-pushed on May 20, 2026
fanquake commented at 3:52 PM on May 20, 2026: member

i'd like to assume you meant 'saves some compilation time' rather than 'saves some compilation' - is that right ?

Maybe both? Skipping LTO means compiling less stuff (albeit not much) in Guix, when building the toolchain, which ultimately saves some time (across 6 toolchains).
winterrdog commented at 6:03 PM on May 20, 2026: none

Skipping LTO means compiling less stuff (albeit not much) in Guix, when building the toolchain, which ultimately saves some time (across 6 toolchains).

correct!

how about updating it to something like: 'This reduces what needs to be compiled and saves some compilation time when building the toolchain'? that way it captures both aspects you mentioned in turn making the description clearer

(just a suggestion though, no worries either way!)
fanquake force-pushed on May 28, 2026
guix: modernise style in *-base-gcc 66e52d110c
guix: disable-lto in *-base-gcc 579f987e96
guix: disable-nls in *-base-gcc 4623e96872
guix: mirror some arguments from linux-gcc to mingw-w64-gcc ec1e8fc2b2

guix: pass --disable-tm-clone-registry to base GCC

We don't need support for transactional memory.

> Disable TM clone registry in libgcc. It is enabled in libgcc by default.
> This option helps to reduce code size for embedded targets which do
> not use transactional memory.

https://gcc.gnu.org/install/configure.html

741de57f06

fanquake force-pushed on Jun 2, 2026

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guix: disable LTO in GCC #35261

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